Search

The impact of bacterial diseases and the development of effective antimicrobial agents have drawn much consideration as a main healthcare challenge. The effects of montmorillonite/silver nanocomposites (MMT/Ag NCs) as a nanofiller on mechanical and thermal properties of linear low-density polyethylene/ethylene–vinyl acetate copolymers blend (LLDPE/EVA) had been investigated. The antimicrobial potential of the synthesized samples had been studied. The developed LLDPE/EVA/MMT/Ag nanocomposites films (NCFs) had been characterized by UV–Vis. spectroscopy, FTIR and XRD analysis. The mechanical, and thermal properties of LLDPE/EVA/MMT/Ag NCFs had been investigated. The results showed that incorporating the MMT/Ag NCs at lower phr (part per hundred resins) content resulted in both improvement in the mechanical properties and the thermal stability. The antimicrobial results demonstrated that LLDPE/EVA blend with 5 phr MMT/Ag NCs possesses the most powerful impact on the tested microbes. The SEM analysis of the treated cells showed, noticeable morphological abnormalities (the complete lysis of the outer surface followed by deformations of cells). Accordingly, the synthesized nanocomposites open the area of interest for possible application in a broad range of purposes like environmental and biomedical applications.

1-Hexene is one of the comonomers used to produce mainly low linear density polyethylene (LLDPE) and high-density polyethylene (HDPE). The production of 1-hexene by ethylene trimerization method gained much interest in petrochemical industry due to its high selectivity towards 1-hexene in comparison to traditional ethylene oligomerization method. In literature, many catalyst systems are reported for ethylene trimerization reaction, but only few of them qualify for the commercial applications. In the present review, activity and selectivity of commercially viable catalyst systems and amount of polyethylene formed as a by-product on using these catalyst systems were discussed. Special attention is given to Chevron Phillips ethylene trimerization technology which is one of the dominant technologies in the production of 1-hexene. The challenges such as fouling issues at commercial plant due to polyethylene by-product formation were discussed and the progress made to overcome the challenges were also discussed. New generation nontoxic titanium catalysts look promising and challenges involved in commercializing these catalysts were presented in the review. Graphic abstract

Recycling post-consumer packaging of high and linear/low-density polyethylene (HDPE, LDPE/LLDPE) and polypropylene (PP) (most representative in any plastic waste stream) is a viable alternative. However, these packages must be washed first, especially those with a high content of contaminants (such as yogurt—HDPE and margarine—PP). Therefore, this study aimed to develop a complete pre-treatment of polymeric wastes (HDPE, LDPE/LLDPE, PP) involving the steps of quantification, characterization, washing (pre-wash/ washing/rinsing), treatment of the generated effluent and the reuse of treated water in a closed circuit. Afterward, the qualification of recyclable material selectors was performed with associations/cooperatives of recyclable material in the Rio Grande do Sul, South region of Brazil. The results indicated that the subdivision in prewash/washing/rinsing utilizing sulfonic acid (1.16% v/v), lauryl (sodium lauryl ether sulfate) (0.53% v/v) and soda (0.31% v/v) was suitable for obtaining clean polymeric waste. Treatment of effluent using aluminum sulfate (4 g L−1) as a coagulant, followed by filtration, was efficient with removal values greater than 90%. These characteristics of treated water allowed its reutilization water of a safe way in closed circuit in the process of washing of the polymeric wastes. Finally, a total of sixty-four selectors of recyclable materials were trained and the theoretical–practical training was quite satisfactory for more than 95% of selectors. Therefore, it can be concluded that the great importance to transmitting the knowledge to society generated in this studies and thus provides best conditions for the development of these selectors of recyclable materials.

A simple and fast method to prepare high-performance graphene to improve polyolefin performance is highly desirable to fulfil the technical requirements of modern society. In this paper, flake graphite was the main raw material used to prepare thick sheet graphene (TSG). (NH4)2PtCl6, H3PO4 and H2SO4 were added to flake graphite to prepare TSG by a hydrothermal method and a high-temperature expansion method. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) results show that the TSG adopted a worm-like structure with large open voids and significantly increased layer spacing, specifically a lamellar structure. TSG/polyolefin composites were prepared by the melt blending method. The XRD results show that melt intercalation of TSG in polyolefin was realized under the action of shear force. When the TSG content was 0.1%, the tensile strength (17.1 MPa), impact strength (58.0 kJ·m−2) and bending modulus (144.3 MPa) of linear low-density polyethylene (LLDPE) increased by 10.4%, 21.0% and 6.6%, respectively. When the TSG content was 0.1%, the tensile strength (19.9 MPa) and bending modulus (278.9 MPa) of polypropylene random copolymer (PPR) increased by 7.7% and 16.7%, respectively. Differential scanning calorimetry (DSC) test results show that the addition of TSG can effectively increase the crystallinity of polyolefin, and the crystallinity of LLDPE and PPR reached 31.5% and 50.4%, respectively. At the same time, the SEM test results show that the addition of TSG can effectively improve the polyolefin profile.

Rotational molding is a technique used to process plastic materials that provide the advantage of obtaining a stress-free end product. While linear low-density polyethylene (LLDPE) is largely preferred for this method, LLDPE is mixed with different additives in order to obtain adequate strength for some critical applications. In contemplation to obtain a sound product, proper mixing of base resin and additives while sustaining rotomoldability is desirable. In the present study, processibility analysis of LLDPE/glass fiber is investigated. Researchers are familiar with the use of glass fibers as an additive in such criteria. However, the rotational molding process has yet to be studied using its industrially processed dust. In particular, the residue of industrially obtained glass fiber (GF) as a waste is mixed with LLDPE in the different weight ratio of 10% to 50%, with 5% increase subsequently. Fourier transform infrared spectroscopy is a technique performed to obtain the optimum percentage range where the result infer the dominant peaks of LLDPE and glass fiber assuring the needed blending. Melt flow index test was carried out to assess the rotomoldability of LLDPE/GF fiber in terms of fluidity. Furthermore, the current research examines the effects on the shear modulus and crystallinity of LLDPE/GF blends based on the rheological and DSC analysis, respectively. In conclusion, the experimental results suggest that 20% LLDPE/GF blend is an optimal percentage for the rotational molding process to achieve requisite processibility.

In this work, the effect of the linear low-density polyethylene (LLDPE) containing 1-butene or 1-hexene α-olefin short-chain branching (SCB) and low-density polyethylene (LDPE) containing long-chain branching (LCB) on the rheological properties of high-density polyethylene (HDPE)/LLDPE and HDPE/LDPE blends was investigated. The neat polymers and the blends were characterized by torque rheometry and rheological measurements under dynamic oscillatory shear flow. From torque rheometry analysis, an increase in the viscosity of HDPE/LLDPE blends with the increase in LLDPE content was observed. The inverse was observed for HDPE/LDPE blend, where the viscosity decreased with the increase in the LDPE content. Rheological measurements showed an increase in the complex viscosity of the HDPE/LLDPE and HDPE/LDPE blends with the increase in the LLDPE or LDPE content. HDPE/LDPE blends showed a strong shear-thinning behavior due to the presence of LCB in LDPE. Similar rheological behavior was observed for HDPE/LLDPE blends containing 1-butene and 1-hexene SCB. Cole–Cole, Han plots, and van Gurp–Palmen plots indicated miscibility between HDPE and LLDPE and immiscibility between HDPE and LDPE.

Linear low-density polyethylene (LLDPE) cast stretch films were fabricated at broad range of line speeds (200–1000 m/min) to investigate the relationship between tensile properties of films and line speed of cast extrusion process, particularly high line speeds as a matter of scientific and economic interest. In addition, tensile experiments were carried out at low and high drawing speeds as well as in both machine and transverse directions (MD and TD). The results illustrated an enhancement of MD modulus (more than 100%) and strength (about 22%) with increasing the line speed from 200 to 1000 m/min, indicating a more pronounced increase for modulus values. Changing the drawing speed, generally, affected the high strain behavior of films. Nevertheless, at the lower strains, the drawing speed influences particularly the modulus of lower line speed films. It was observed that increasing the line speed in the cast film line has stronger effects on the film elongation behavior than the drawing speed in tensile tests. The tensile properties along TD showed greater deviations from MD tensile behaviors as line speed increased. The variations of tensile properties by line speed were due to chain orientation and extension especially in the amorphous phase. Furthermore, the surface morphology of the LLDPE films were also observed, and it was found that increasing the line speed leads to reduction of surface roughness.

Polyethylene is widely used due to its excellent properties. However, the growing demand and higher production of polyethylene have also brought new types of hazards. It is essential to study the pyrolysis of polyethylene for the polyethylene process conditions and the prevention of polyethylene dust explosion. In this paper, the pyrolysis of linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE) under different heating rates in N2 and different ethylene concentration was studied by the TG-DSC method. The pyrolysis kinetics of polyethylene was analyzed by using Li Chung-Hsiung thermal analysis method, and the pyrolysis characteristic and reaction kinetics parameters of LLDPE and HDPE were found. The research results show that the increase in the heating rate is beneficial to polyethylene pyrolysis in nitrogen. The temperature at the highest rate increases linearly with the heating rate. The rise of ethylene concentration has some inhibitory effect on the pyrolysis reaction of polyethylene, and ethylene has a significant impact on the polyethylene pyrolysis rate. We also found the most suitable mechanism function of polyethylene pyrolysis from the 12 considered mechanism functions. HDPE pyrolysis stability is higher than LLDPE in nitrogen, while LLDPE pyrolysis stability is higher than HDPE in ethylene.

Polyethylene (PE)/silica polymer nanocomposites (PNCs) were investigated mainly using rheological measurements. Various PEs [linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and low-density polyethylene (LDPE)] were selected as polymer matrices, and two comparable particulate silicas were utilized as favorable (hydrophobic, R202) or unfavorable (hydrophilic, A90) fillers. Small amplitude oscillatory shear (SAOS), large amplitude oscillatory shear (LAOS), elongational rheometry, tensile tests, and TEM were adopted to characterize PE/silica PNCs. LDPE/silica nanocomposites showed the best filler dispersion in TEM images but were the poorest in terms of rheological property enhancement. Linear viscoelasticity as determined by SAOS testing was discordant with their morphology. However, nonlinear viscoelasticity as determined by FT-rheology in LAOS testing adequately determined dispersion states. Elongational viscosity revealed LDPE/silica PNCs show strain-hardening behavior, which resulted in intense mixing conditions and best compatibilization on LDPE/silica PNCs. To quantify the strain-hardening effect, strain hardening coefficients (SHCs) were calculated for LDPE/silica PNCs and found to decrease with increasing silica concentration. In addition, tensile testing showed mechanical properties deteriorated with silica content.

A study was undertaken to assess the effectiveness of plastic laminated collapsible tube as a packaging material for honey. Honey was packed in 100 ml capacity laminated tubes having a structure of linear low density polyethylene/aluminum foil/linear low density polyethylene and were exposed to 27 ± 2 °C and 65 ± 2% RH for a period of 12 months. The filled packages were withdrawn at regular intervals from the climatic chamber and product was analyzed in the laboratory. The physico-chemical parameters like moisture content, TSS, pH, etc., were found to be within the permissible limits. The moisture content ranged between 15.22 and 22.53% and TSS was 75.05 and 77.10°Bx. The pH (4.05–4.47) of honey remained unaffected during the entire period of storage and barrier properties of the laminated tubes showed synergistic interaction which inhibited the microbial growth. The honey samples showed overall higher sensory score and no changes in the packaging material in terms of softening, cracking, bulging or delamination were observed. So, it could be concluded that the barrier properties of the plastic laminated collapsible tube can maintain the keeping quality of honey for 370 days at normal storage conditions.

Composite substrates of linear low-density polyethylene with thermotropic liquid crystals as inclusions with three different weight fractions were synthesized. The dielectric characterizations of the composites in X band frequencies were studied to assess their applicability as substrates for microwave devices. Thermotropic liquid crystals, NN-(terephthalylidene)bis(4-n-butylaniline), NN-(terephthalylidene)bis(4-n-hexylaniline) and NN-(terephthalylidene)bis(4-n-decylbenzamine) were synthesized in the laboratory at room temperature. Structural characterization for synthesized thermotropic liquid crystals was done using nuclear magnetic resonance and Fourier transform infrared spectroscopy. To confirm the distribution of liquid crystal inclusions in the polymer matrix, scanning electron microscope images were used. Water absorbance test was carried out following Archimedes’ principle. The real part of complex permittivity and the dielectric loss tangent at X band frequencies for all the weight fractions of the composite were found to be ~ 2.1–2.4 and ~ 10−2–10−4 respectively. The magnetic loss tangent was also measured for the substrates and showed values within the range of 10−1–10−2. To establish the suitability of the fabricated substrates for use in antennas, the return losses were calculated using the complex permittivity and permeability values.

The principal objective of this study was to assess the capability of waste rice husk fibers as reinforcement for recycled plastics. The fabrication of Wood-plastic composites (WPCs) based on rice husk (RH) fibers and recycled linear low polyethylene in the presence of maleic anhydride grafted polyethylene (3 phc) were made by melt blending method. The impact of nanosilica and nanocaly, at different concentrations (2, 4, and 6 phc) on morphological, physical–mechanical and thermal properties of the prepared WPCs were studied to distinguish the most efficient nanoparticle. The highest improvement of mechanical properties was achieved at 6phc nanosilica loading and 4phc nanoclay. At a high level of nanoclay loading (6phc), increased population of clay pellets leads to agglomeration, and stress transfer gets blocked. Izod impact strength was decreased by the incorporation of different nanoparticles in contrast with the hardness. The addition of different nanoparticles decreased the water absorption and thickness swelling of composites. The interaction of the rice husk fibers with the polymer matrix as well as the impact of nanosilica and nanoclay in the improvement of the adhesion was shown by scanning electron microscopy (SEM). In addition, the thermal stability showed slightly improved by the addition of nanoparticles, but there are no perceptible changes in the values of melting temperature by increasing the nanosilica and nanoclay content. The degree of crystallinity (Xc) of the composites decreased with the incorporation of RH fibers and increased with the addition of nanoparticles. The finding demonstrated that WPCs treated by nanosilica had the most elevated properties than nanoclay.

Date pit/ glass fiber reinforced LLDPE hybrid composites were compounded by single screw extruder and injection molded into dumbbell specimens. The composites were subjected to thermal gravimetric analysis (TGA), tensile testing, flexural study and water absorption analysis. TGA study confirmed the positive hybrid effects of reinforcements on the thermal stability of LLDPE composites. The decrease in weight loss percentage with the addition of glass fiber authenticated the increase in thermal stability. The maximum tensile strength 20.2 ± 0.8 MPa was obtained with 10% date pit and 20% glass fiber. The water-resistant property of hybrid composites reinforced with high percentage of glass fiber was found to be improved in comparison with virgin. The resulting composites were also exposed to different gamma doses (75 and 150 kGy) and the effect is characterized in terms of thermal and mechanical properties. Irradiation of gamma rays under 75 kGy improved the thermal stability and tensile strength than unirradiated and irradiated samples at higher dose (150 kGy).

The production of composite materials from post-consumer polypropylene car bumper waste (PP-CBW) and short glass fibers (SGF) by melt processing was investigated during this study. To improve the interfacial adhesion between the fibers and the matrix, two coupling agents maleic anhydride-grafted linear low-density polyethylene (LLDPE-g-MA) and Retain were introduced during the compounding process. The effect of various SGF loadings, types of coupling agents, SGF to coupling agent ratio and short glass fiber length on thermal, physical and mechanical properties were thoroughly investigated during this study. Differential scanning calorimetry (DSC) analysis indicated significant changes in the crystallization temperature (Tc) and percentage crystallinity (Xc) when the SGF content and length were modified. It was deduced also from thermal analysis that using LLDPE-g-MA as a coupling agent increases the nucleating role of the SGF by effectively distributing the fibers inside the matrix. The average length (Lave) was found to decrease with increasing the SGF loading. On the other hand, Lave values increased with the original glass fiber length and when a SGF/LLDPE-g-Ma ratio of 5:1 was used compared to the ratio 3:1. The incorporation of SGF improved drastically the flexural and the tensile properties but decreased the impact properties. The impact properties improved when a ratio of SGF/LLDPE-g-MA of 3:1 was used. However, the flexural modulus was reduced and no significant effect was observed on the tensile and flexural strength. Mechanical results showed also that the LLDPE-g-MA is a better compatibilizer than Retain for stiffness and strength, whereas Retain composites resulted in higher impact properties than LLDPE-g-MA composites. Stiffness decreased when fiber length increased from 6 to 12 mm and the same tendency was observed for tensile and flexural strength denoting that poor fiber dispersion and distribution was achieved for high fiber length. The scanning electron microscopy (SEM) results revealed that SGFs are evenly distributed in PP-CBW matrices, and no distinct voids appear between these two materials, indicating a good interfacial adhesion.

Lignins are promising alternative raw materials for biocomposites due to their renewability, low cost and abundance. In this work, the use of (softwood and hardwood) Kraft lignins in the development of LLDPE/lignin films for agricultural mulch applications is studied. Processable blends were obtained from unmodified softwood lignin (SW) and from hardwood lignin modified by esterification (HWE). LLDPE was pelletized with (2.5%, 5% and 10%) lignin with particle size between 38 and 75 μm and flexible films were blown extruded. Processable extrusion blends showed temperature differences lower than 20 °C between the Tg of lignin and the melting temperature of LLPDE. Films from neat LLPDE and with 2.5% of HWE and up to 5% SW exhibited statistically comparable (≅ 349%) values of ductility. Ester groups present in lignin improve weight loss of lignin-based blends after soil buried test.

This paper is dealing with the polyisobutylene (PIB) migration phenomenon through the post-consumer agricultural waste multilayer films based on four linear low-density polyethylene (LLDPE) matrices. Through this work, a bridge between shear, elongational rheology, and tack surface properties was revealed on both model and recycled blends. Hereto, effects of aging time and temperature were investigated and rationalized depending on the short- and long-chain branching in LLDPE matrices as well their polyethylene (PE) crystallization. The linear viscoelastic properties were influenced despite the small PIB amounts. This migration influenced also the slippage in steady flow regime. It was also demonstrated that transient uniaxial extensional properties are very sensitive in the presence of PIB, which seems to hold back the PE strain hardening properties. Therefore, the axial force and the surface friction coefficient were determined and discussed in correlation with bulk rheological findings. Hence, the obtained results contributed to unveiling new insights on the physical mechanisms governing the PIB migration with or without fillers to inhibit its migration in their recycled films.

We investigated the rheological behavior of linear low-density polyethylene (LLDPE)/polylactic acid (PLA) blends in the presence of modified and non-modified silica nanoparticles in extensional flow. Characterization methods were used as Fourier transform infrared spectroscopy, scanning electron microscopy, and rheometric measurements under shear and uniaxial extensional flows. The rheology behavior of LLDPE significantly was changed by the addition of PLA and silica nanoparticles. Extensional results showed that the elongational viscosity of the blends intensified by the incorporation of silica nanoparticles. Strain hardening was observed for LLDPE containing 2 wt.% of the unmodified silica nanoparticles, which disappeared by enhancement of the unmodified silica from 2 to 8 wt.%. Furthermore, elongation thinning was observed for the filled blends at high loading, which was more sensitive to the strain rate by increasing of PLA. Surface modification of silica was demonstrated in different elongational behavior. Indeed, a fracture took place by loading the modified silica nanoparticles in LLDPE; however, the intensity of this behavior dramatically increased for filled blends with a high loading of modified silica.

The structural evolutions of LLDPE-LMW/HMW blend during uniaxial deformation at temperatures of 80 and 120 °C were investigated by the in situ synchrotron radiation small- and wide-angle X-ray scattering (SR-SAXS/WAXS). The magic sandwich echo (MSE) sequence was used to detect a virtually dead-time-free induction decay (FID) for solid-state NMR analysis. The thermal property of the blend was first checked by DSC, and the temperature dependence of the overall crystallinity was obtained by MSE-FID. The onset melting temperature is determined to be 116 °C (DSD), and the enhanced π-flip motions in the crystalline domains are clearly observed at T > 60 °C by MSE-FID. For deformation at 80 °C, the lamellae become staggered in the strain-softening region as shown by the four-point SAXS pattern, whereas further deformation leads to the melting-recrystallization in the strain-hardening region. For deformation at 120 °C, the six-point SR-SAXS signal appears just after the four-point SR-SAXS signal, which indicates the formation of new lamellae along deformation direction. In addition, no phase transition occurs in the whole deformation process at both temperatures. Current work shows the detailed temperature dependence microstructural evolution of LLDPE-LMW/HMW blend. This is expected to provide more structural information for correlating microscopic structure with macroscopic mechanical performance.

Atmospheric plasma was utilized to modify linear low-density polyethylene (LLDPE) film. On that basis, formaldehyde emission (FE)-free plywood was prepared using plasma-treated LLDPE film as the adhesive. Obtained results suggested that atmospheric plasma treatment leads to grafting of multiple oxygen-containing groups, thus evidently elevating the surficial polarity of LLDPE. Enhanced interaction between polar groups contributed to improve interfacial compatibility and interfacial adhesion between LLDPE and poplar veneer. Prepared by plasma treatment on both LLDPE and veneer, LLDPE/poplar plywood exhibited fine shear strength (around 0.87 MPa) and dynamic mechanical properties. Furthermore, the mechanical properties of plasma-treated LLDPE/poplar plywood were similar to those prepared by coupling agent treatment. It is believed that plasma treatment is a promising way to overcome the inherent hydrophobic surface of LLDPE and therefore improve the interfacial adhesion between LLDPE and wood. LLDPE/poplar plywood can be effectively manufactured using plasma treatment with reduced chemical consumption and total cost. The FE of prepared LLDPE/poplar plywood was remarkably low, indicating its suitability for indoor applications.

Hydrostatic cyclic expansion extrusion (HCEE) process at elevated temperatures is proposed as a method for processing less deformable materials such as magnesium and for producing long ultrafine-grained rods. In the HCEE process at elevated temperatures, high-pressure molten linear low-density polyethylene (LLDPE) was used as a fluid to eliminate frictional forces. To study the capability of the process, AM60 magnesium rods were processed and the properties were investigated. The mechanical properties were found to improve significantly after the HCEE process. The yield and ultimate strengths increased from initial values of 138 and 221 MPa to 212 and 317 MPa, respectively. Moreover, the elongation was enhanced due to the refined grains and the existence of high hydrostatic pressure. Furthermore, the microhardness was increased from HV 55.0 to HV 72.5. The microstructural analysis revealed that ultrafine-grained structure could be produced by the HCEE process. Moreover, the size of the particles decreased, and these particles thoroughly scattered between the grains. Finite element analysis showed that the HCEE was independent of the length of the sample, which makes the process suitable for industrial applications.

The synthesis and olefin polymerization behavior of a new TADDOL-based Ti(IV) complex, (4R,5R)-2,2-dimethyl-α,α,α′,α′-tetrakis[bis-(3,5-trifluoromethyl)phenyl]-1,3-dioxolane-4,5-dimethanolato-titanium(IV) dichloride, are described. Upon activation with MAO, this complex polymerized ethylene, producing ultra-high molecular weight linear polyethylene (UHMWPE) with activities up to 4500 kg mol (Ti)−1 [C2H4]−1 h−1 atm−1 and molecular weights up to 3.25 × 106. The optimal temperature for UHMWPE synthesis was 50 °C. This complex is also capable of copolymerizing ethylene with 1-hexene and 1-octene, giving high molecular weight copolymers with α-olefin incorporation up to 7.8%. The copolymers, obtained with a different ratio of comonomers, are statistical, according to the analysis of the 13C NMR spectra. The reaction parameters that influenced the copolymerization behavior, such as comonomer concentration, reaction temperature and [Al]/[Ti] molar ratio, are examined in detail. Furthermore, high catalytic activities up to 12,531 kg mol(Ti)−1 [C2H4]−1 h−1 atm−1 were observed in copolymerization of ethylene and 1-hexene or 1-octene with the 2/MAO catalytic system. The obtained copolymers possess high molecular weights (Mw = 1.4 × 106—ethylene/1-hexene and 1.86 × 106—ethylene/1-octene) with broad MWD (Mw/Mn = 3.04–8.23) and high comonomer incorporation degrees (up to 6.2 mol% of 1-hexene and 7.8 mol% of 1-octene). Depending on the synthesis conditions, it is possible to form both a statistical copolymer and a block copolymer.

Rotational molding or rotomolding is a powder processing technique used for the manufacturing of hollow plastic products. The present work investigates the moldability of long bamboo fiber as the reinforcement for linear low-density polyethylene (LLDPE) matrix. The temperature of the mold, oven and internal air temperature of the mold has been recorded to study the heat transfer rate while processing composites with different weight percentage. Mechanical properties were found to be improved by 5% fiber addition, and beyond that, the properties were reverted. Morphological characterization was done to analyze the interfacial properties of fiber and matrix. The present work successfully incorporated long bamboo fibers with LLDPE powders and uniformly distributed these fibers along the sides of the mold without applying any external pressure. Thus, it is concluded that fiber incorporation is possible in the rotomolding process and homogenous randomly oriented fiber dispersion can also be achieved by the rotational molding process.

To extend the period of decomposition and property degradation of polybutylene adipate terephthalate (PBAT) mulching film for long-term use, PBAT was compounded with polyethylene mixture (LDPE: LLDPE = 15:85), calcium carbonate, and illite. PBAT mulching films were prepared using a blown film extrusion process with 80 mm diameter blowing die. To improve mechanical properties and processability of the film, crosslinking agent di-(t-butylperoxy isopropyl) benzene (BIBP) was added to PBAT compound and the effect of BIBP content on compatibility enhancement of PBAT and PE was investigated. Rheological measurements through dynamic oscillatory frequency sweep showed that the storage modulus of PBAT compound increased with the addition of BIBP and the slope of it decreased in the low frequency region because of crosslinking increase of PBAT and PE. Melt flow index of PBAT compounds decreased with increasing BIBP content. In the blown film extrusion process, the temperature of the heating zones in the extruder increased and the flow rate of the cooling air decreased with increasing content of BIBP. The highest output rate and a uniform surface morphology of mulching film were obtained because of a stable bubble with a tubular shape even at high extrusion speed with 800 ppm of BIBP. In addition, tensile strengths of both machine and transverse directions were the highest among all PBAT compounds. When the content of BIBP was higher than 800 ppm, the surface inhomogeneity of the film increased, resulting in decrease of the tensile strength in machine and transverse directions due to increased chemical cross-linking of PE and PBAT.

Rotational molding is an idiosyncratic plastic manufacturing technique that provides a comparatively stress free end product. The base resin extensively preferred for rotomolding is Linear Low Density Polyethylene (LLDPE). However, when compared to common engineering materials, pure LLDPE embarks poor mechanical properties targeting few critical applications. Usage of glass fibres as an additive is well known to the researchers in such criteria. But its industrially processed dust is yet to be investigated for rotational molding process. Thus, in the current context, rotationally molded LLDPE based products are investigated wherein glass fibres dust (GFD) are embedded into thermoplastic resin to examine the variation in strength and stiffness of end product. According to preliminary processing tests conducted, approximately 20% and below of LLPDE/GFD composites was observed to provide better fluidity as a prerequisite for rotomoldability. Hence, an experimental study was performed to benchmark the presence of 10%, 15%, 20% and 25% GFD when mixed with LLDPE for rotomolded product. When treating LLDPE/GFD at distinct weight ratio, the rate of heat transfer was also evaluated using the mold, oven, and internal air temperature. The composite's crystallinity was investigated using DSC analysis to assess the concentration of GFD incorporated in LLDPE. Scanning electron microscopy was furthermore utilized to display the underlying mechanisms of LLDPE/GFD ratios. The present work successfully signifies an increase in an overall performance due to the impact of GFD over unreinforced LLDPE. Therefore, it is hypothesized that till 20% GFD addition in the LLDPE matrix is expected to lead a rise in mechanical properties, thus potentially approaching towards retaining the requisite degree of design freedom of rotational molding process.

A secondary master batch process had been applied to design a polyolefin encapsulant material for photovoltaic modules, in which the polymer blend was composed of polyolefin elastomer (POE) and linear low-density polyethylene (LLDPE) with the addition of the cross-linking agent of tert-butylperoxy 2-ethylhexyl carbonate (TBEC) and silane coupling agent of γ-methacryloxypropyl trimethoxy silane (KH570). The rheological property from Haake torque rheometer illuminated that the chemical cross-linking reaction could take place between the POE and TBEC. The LLDPE was added for further increasing the cohesion of polymer blend by obtaining much more physical cross-linking points from the physical entanglement between the flexible chains of LLDPE and the amorphous zone of POE. However, the transmittance of polymer blend ran down with the rise of LLDPE content within the polymer blend. The number and site of melting points of polymer blend by the DSC analysis show that there was compatibility between the POE and LLDPE within the polymer blend; meanwhile, the resultant molecular structures of the polymer blend also had been explained by the FTIR spectra. These results unanimously illuminated that it was a feasible solution for fabricating the polyolefin encapsulant material for photovoltaic modules.

Polyamide 6 (PA6) is a polymer largely applied in the packing industry; however, it has limitations like high water absorption, notch-sensitive impact and high electrical resistance. Some strategies have been developed aiming to improve these drawbacks, as blending PA6 with other polymers, like linear low-density polyethylene (LLDPE) which is also an electrical insulator. In this work, antistatic packages for the transportation and storage of electronic devices were prepared by mixing PA6 and LLDPE with the addition of carbon black as an antistatic agent to reduce the electrical resistivity of polymers. PA6/LLDPE (50/50) blend-based carbon black composites with different contents of carbon black (5, 10 and 15 wt%) were prepared in a twin screw extruder, and their mechanical, rheological, electrical and permeation properties were studied. Thereby, the effects of the addition of maleic anhydride-grafted LLDPE (LLDPE-g-MA) in the composites were also studied. The addition of LLDPE-g-MA and 5 wt% and 10 wt% of carbon black in the PA6/LLDPE blend resulted in a 130 and 150% increase in impact strength, respectively. Adding 10 wt% of carbon black in the PA6/LLDPE/LLDPE-g-MA blend increased the elastic modulus, reduced the electrical resistivity by 14 decades and also reduced the water vapor permeability, allowing this material to be eligible for use as antistatic packaging.

Waste eggshells were used to decorate functionalized carbon nanotubes (CNT) and graphene oxide (GO) by hydroxyapatite (HAP) using in situ synthesis. The HAP decorated CNT and GO were characterized by X-ray diffraction, SEM, and IR spectroscopic techniques. CNT-HAP and GO-HAP were further used to prepare polymer nanocomposites by addition of different percentages of synthesized CNT-HAP and GO-HAP as fillers into linear low density polyethylene (LLDPE). The prepared nanocomposites specimens were utilized for physical and thermo-mechanical analysis. Mechanical properties of the LLDPE nanocomposites were improved with increasing the percentage of CNT-HAP and GO-HAP fillers compared to the pristine LLDPE. Hardness of hybrid-CNT-HAP/LLDPE composite was increased as compared to the GO-HAP/LLDPE, where as tensile strength of the GO-HAP/LLDPE was higher than that of the CNT-HAP/LLDPE composite. Flammability of CNT-HAP and GO-HAP composites was decreased by 32% as compared to the pristine LLDPE.

A silane moisture-cured polyolefin elastomer/linear low-density polyethylene (LLDPE) blend was prepared through a two-step silane-grafting method (Sioplas Process) in an industrial scale twin-screw extruder. The silane-grafted compound was used to make wire and cable coatings. In this work, the effect of some interactive parameters on quality of the products prepared by the above method has been studied, while so far, there have been less experimental investigations. The volume resistivity of cross-linked compound was changed from 2.96 × 1014 to 7.41 × 1014 Ω cm with increasing LLDPE component by maximum 10 wt%. Surface morphology of the product was corrected with reduction in benzoyl peroxide (BPO) concentration from 0.2 wt% to 0.13 wt%. BPO at this level acted as an initiator in grafting reaction of vinyl trimethoxysilane. The curing condition and specimen preparation method by injection molding and/or extrusion were factors which influenced the hot-set test results at 200 °C. The results of tensile and elongation studies showed a maximum value of 9 MPa and 397% for the tests, after 6 h curing. With increases in curing time at a specified temperature, the gel content of the cross-linked compound was increased and reached its maximum value. The maximum gel content values were found to be approximately 60%, 80%, and 82% at temperatures of 25, 60, and 85 °C, respectively. The hardness, density, and tear strength of the samples did not vary significantly with the curing temperature.

Iron poly(acrylic acid-co-acrylamide) (FeAA) and melamine polyphosphate (MPP) were synthesized, characterized by FTIR and blended with linear low-density polyethylene (LLDPE). The thermogravimetric analysis results exhibited that MPP, FeAA and MPP/FeAA increased the char residue of LLDPE at 750 °C. Cone calorimeter data demonstrated that MPP, FeAA and MPP/FeAA decreased the peak of heat release rate (pHRR) and total heat release of LLDPE. Digital photographs, SEM images, EDXS and FTIR analyses of char formed after cone test indicated that the presence of FeAA did not support formation of coherent char during combustion process of LLDPE. In contrast, LLDPE/MPP composite formed high-quality char layer on polymer surface. Moreover, addition of MPP to LLDPE/FeAA composites assisted in formation of char containing iron polyphosphate and polyaromatic structure. The mechanical properties, namely tensile strength, Young’s modulus, elongation at break and hardness of LLDPE composites, were measured.

In this study, the properties of virgin linear low-density polyethylene (LLDPE) and its blends with reclaimed plastic solid waste (PSW) are investigated by thermogravimetry, differential scanning calorimetry (DSC), infrared spectroscopy and scanning electron microscopy (SEM). The PSW constituted polyolefin (PO) polymers recycled mechanically via extrusion/blown-film and exposed to accelerated weathering tests to determine the change in their degradation behaviour. The oxidation products determined using the FTIR analysis and thermal stability studies points toward the blend constituting 25% of waste by weight as the most stable. Changes in crystallinity of the polymers were attributed to the crystal size change as a consequence of the weathering mechanism. The DSC results revealed that both oxidation induction temperature (OIT) and crystallinity were affected by the PO waste content. This points towards the impact of polymers immiscibility and polydispersity within the matrix of the blends due to chain scission reaction and oxidation with the UV exposure.

In this study, the PLA (v) and PLA-Corn starch based biodegradable films (90:10, 80:20) along with reagents BPO (benzyl peroxide) and GMA (Glycidylmethacrylate) was developed using commercial extrusion blown molding method. The haze %, tensile strength, OTR, WVTR parameters of the developed films varied from 16.38–94.73%, 56.49–24.18 MPa, 318.25–171.01 cc/m2/day and 175–101.47 (gm/m2/day), respectively for the developed films. The addition of corn starch decreased Tg from 65.26 to 59.712 °C, Tm from 146.81–150.56oC with a slight increase in Tc from 106.45 to 107.7 °C. The suitability of capsicum in modified atmospheric packaging was studied using the developed biodegradable films. Capsicum was stored under MA in the developed films namely, virgin PLA, PLA-corn (10%), PLA-corn (20%) of size 28 cm × 16 cm having packaging area for the transmission of gas of 0.0896 m2 with a fill weight of 0.35 kg. Polymeric film made up of LDPE+LLDPE of 60 µm was used for comparison. The MA packages maintained ≤ 5% PLW and higher firmness of samples as compared to the unpackaged capsicum. MA packages maintained the quality of capsicum up to 12 and 24 days at 25 and 8 °C, respectively as compared to unpackaged capsicum having shelf life of 4 and 9 days at 25 and 8 °C, respectively.

Doing experiments in order to determine mechanical properties of nanocomposites costs a lot. Therefore, finding the ways by which the properties of the nanocomposites can be predicted without any empirical or few number of empirical experiments seems to be useful. In the present study, efforts have been made to create a relation between mathematical model based on dimensionless number (Ch) and mechanical properties of low-density polyethylene/linear low-density polyethylene/styrene ethylene butadiene styrene (LDPE/LLDPE/SEBS) nanocomposite reinforced by nanoparticles of calcium carbonate. The proposed model is able to predict mechanical properties of nanocomposites based on their composition. This model is capable to predict elongation at break in terms of Young’s modulus and fracture toughness, and to predict fracture toughness in terms of Young’s modulus and elongation at break. The results showed prediction of the dimensionless number Ch model, and the experimental results are consistent.

This study investigates the influence of two functionalized polyethylene-1-octene elastomers (POEs), POE grafted itaconic acid (POE-g-IA) and POE grafted maleic anhydride (POE-g-MA), on mechanical and barrier properties of a novel nanocomposite. The composition was prepared from linear low-density polyethylene (LLDPE), thermoplastic starch (TPS), and organo-modified clay using the melt blending method. Characterization of the functionalized POEs and nanocomposites was performed using attenuated total reflection- Fourier transform infrared (ATR-FTIR) spectrophotometer, X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), mechanical, and barrier analysis. The ATR-FTIR spectrums confirmed the grafting of POE with itaconic acid and maleic anhydride. It was observed that the adding of compatibilizers have different effects on morphological, mechanical, and barrier properties of the nanocomposite. The d-spacing of the clay platelets was increased by 20 % and 15 % with POE-g-IA and POE-g-MA incorporation, respectively. The functionalized POEs improved the interfacial adhesion between starch and LLDPE. However, POE-g-IA showed better performance compared to POE-g-MA. Better dispersion of clay particles with POE-g-IA and profitable interaction of starch and LLDPE matrix improves mechanical properties. Besides, the oxygen gas permeability and diffusion coefficient from POE-g-IA contained nanocomposite decreased by 14 % and 22 %, respectively, compared with the other functionalized POE, due to the better dispersion of nanoclay.

Polymer waste was subjected to biodegradation evaluation after compounding specimens with an oxo-prodegradant chemical (PDQ-M) and thermoplastic starch, to determine its susceptibility to degrade with time in contact with soil simulating an arid environment. The ASTM D 5988–18 test method was followed to evaluate the biodegradation extent of the materials under investigation, whilst using linear low density polyethylene (LLDPE), polycaprolactone (PCL) and TPS alongside the starch (positive control) as reference materials. The samples were also subjected to thermal characterisation using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), in addition to studying their infrared spectra (IR). It was noted that the LLPDE and the oxo-prodegradant induced polymer waste had a similar degradation extent evaluated after rigorous testing and monitoring, which was 23% after 180 days of experimental time. Furthermore, a plateau was reached for the biodegradation (%) as a function of time after some 50 days, which indicate that the additives in the samples act as a source of nutrient to sustain the biodegradation by enriching the microorganisms in the soil to produce carbon. The work in this study points towards a new method for treating polymer waste using physical blending with additives to biodegrade it with time as promising alternative for plastic waste accumulation.

Rotational Molding is a unique polymer processing technique that gives an advantage of having stress free end product. Majorly, Linear Low Density Polyethylene (LLDPE) is preferred as a base resin for rotomolding. However, incorporation of additives becomes necessary to improve mechanical properties and viscoelasticity as incumbent for few applications. The present research makes an attempt to investigate the effect of coir fiber on rotationally moldable LLDPE. Based on preliminary processing experiments, 10% or less Coir in its powder form when mixed with LLDPE was found to account a better flow ability as a prerequisite for roto moldability. Hence, the effect of 3%, 5%, 7% and 10% Coir mixed with LLDPE was experimented for the roto molded product to determine the mechanical properties, viz. tensile, flexural, hardness and impact strength. Also, the rate of heat transfer was evaluated subjected to the data recorded for mold, oven and internal air temperature when processing LLDPE/Coir considering different weight percentages. Crystallinity of the blend was examined based on DSC analysis for the distinguished percentage of coir incorporated in LLDPE. The experimental results depicted an improvised mechanical properties by 7% or less fiber addition, and beyond that, the properties were found to be regressed. The present work successfully engulfed Coir with LLDPE, producing a uniform distribution along the sides of the mold without applying any external pressure. Therefore, fiber integration in the rotomolding process is believed to be possible thus preserving homogeneous randomly distributed fiber dispersion.

To prepare high-density polyethylene (HDPE) films with excellent mechanical properties and lower haze, HDPE was modified by using linear low-density polyethylene (LLDPE) and polypropylene (PP), and their characterizations were performed by melt index, light transmittance/haze, dart impact and elongation at break, infrared (IR) spectra, scanning electron microscopy image and IR image analyses. The results showed that the modifying effect of the 10% PP/30% LLDPE/60% HDPE composition was the best; the haze was reduced 6% and the translucency, dart impact strength, elongation at break and tensile strength were increased 1, 27.3, 29.4 and 1.0%, respectively. The blend of 10% PP/30% LLDPE/60% HDPE had good compatibility, and PP, LLDPE and HDPE were only the physical entanglement, and no chemical reaction, the modified HDPE films can partly replace polyvinyl chloride and LLDPE films.

A mechanical tough polylactic acid (PLA) that substantially retains its stiffness and transparency was created through reaction with a polyrotaxane derivative. A graft polyrotaxane (GPR), composed of a linear Polyethylene glycol backbone threaded with cyclodextrins bearing grafted poly(e-caprolactone), was bonded to the hydroxyl end-groups of PLA with hexamethylene diisocyanate (HDI), which then solidified to form a PLA-bonded GPR that was distributed throughout the PLA matrix. The addition of 5 wt% GPR resulted in a seven-fold increase in Izod impact strength and a three-fold increase in fracture elongation, with only an 11% loss of stiffness; the transparency was comparable to neat PLA. Electron microscopy revealed that HDI facilitated the dispersal of GPR in the PLA matrix and avoided the sea-island phase-separated structure observed in the PLA/GPR blend devoid of HDI, and that the homogenized structure led to ductile deformation. A GPR content of only 5 wt% efficiently increased PLA-matrix-chain flexibility.

Extrusion film casting (EFC) is an industrially important process which produces thousands of tons of polymer films, sheets, and coating used for various industrial as well as household applications. In this paper, we focus on an instability which occurs during certain polymer processing operations operating under predominantly elongational flow, such as extrusion film casting and fiber spinning. This instability, called the draw resonance, occurs in the form of sustained periodic fluctuations in the film dimensions. It appears when the process goes beyond the critical line speed of the EFC process. In this work, a conventional linear stability analysis is carried out for nonisothermal EFC process to determine the onset of the draw resonance. The polymer rheology is modeled by the Phan-Thien Tanner (PTT) multi-mode constitutive equation. For the implementation, a conventional shooting method approach is used. Extrusion film casting experiments were also carried out using a conventional linear low-density polyethylene (LLDPE) by varying process parameters such as draw ratio and aspect ratio, to observe the effect on the stability of the process. Linear stability analysis results under non-isothermal conditions are compared and validated with existing results from literature and with our own experimental data. This work displays the effect of multiple relaxation modes as well as the temperature influence on the stability of EFC process. Finally, results also indicate that the temperature highly affects the stability of the EFC process and cannot be ignored from modeling of EFC process.

Foamy phase-change materials (FPCMs) based on linear low-density polyethylene (LLDPE) blended with 30 wt.% of paraffin wax (W) were successfully prepared for the first time. The advantage of these materials is their double functionality. First, they serve as standard thermal insulators, and second, the paraffin wax acts as a phase change component that absorbs thermal energy (the latent heat) during melting if the temperature increases above its melting point, which ensures better heat protection of buildings, for instance, against overheating. The density of the porous fabricated FPCM was 0.2898 g/cm3 with pore content 69 vol.% and gel portion achieved 27.5 wt.%. The thermal conductivity of the LLDPE/W foam was 0.09 W/m.K, whereas the thermal conductivity of the neat LLDPE foam prepared under the same conditions was 0.06 W/m.K, which caused a higher porosity of approximately 92 vol.%. The FPCM absorbed or released approximately 22–23 J/g during melting or cooling, respectively, and the material was stable under thermal and mechanical cycling.

In the current study, huntite and hydromagnesite (HH) was used as flame-retardant additive in linear low-density polyethylene (LLDPE). The effect of HH amount on the flame-retardant and mechanical properties of the composites was investigated. The compatibilizer (ethylene butyl acrylate) use and the surface modifications with stearic acid and silane coupling agent were used in order to improve the mechanical properties of the composites. The mechanical properties of the composites were studied using tensile test and dynamic mechanical analysis. The fire-retardant properties of the composites were investigated using limiting oxygen index (LOI), mass loss calorimeter, vertical (UL 94 V) and horizontal (UL 94 HB) burning tests. According to the flammability test results, LOI value increased, horizontal burning rate reduced as the added amount of HH increased, whereas UL 94 V rating remained burn to clamp. According to the mechanical test results, the addition of HH reduced the tensile strength and elongation at break values and increased the elastic modulus and the β transition temperature of the LLDPE as the added amount increased. Only the compatibilizer use improved the flammability properties of the composites with improved tensile strength. Both stearic acid and silane modification merely increased the toughness of the composites.

Potato peel (POPL), an agricultural waste material, obtained from food industry has been used as filler in the powdered form in linear low-density polyethylene (LLDPE) matrix up to 40% (w/w) to prepare biocomposites. The effect of addition of functional polyolefin compatibilizers—maleic anhydride-grafted polypropylene (MA-g-PP) and maleic anhydride-grafted polyethylene (MA-g-LLDPE), up to 5% (w/w) in POPL/LLDPE biocomposites were also studied. Scanning electron microscope was used for morphological characterization and X-ray diffraction for crystallization studies. Tensile strength of LLDPE biocomposites with MA-g-LLDPE compatibilizer reduced only in the range of 12.0–13.4 MPa compared to 14.6 MPa in neat LLDPE, however, reduced up to 40% in LLDPE biocomposites with 40% POPL content. Remarkable improvement in tensile modulus from 75.7 to maximum 703 MPa was achieved among the biocomposites. Mechanical properties of LLDPE biocomposites with 10% (w/w) POPL filler were comparable to neat LLDPE. Addition of maleic anhydride-grafted polyolefins has enhanced flexural strength and flexural modulus of biocomposites with compatibilizers’ up to 128 and 188%, respectively, compared to neat LLDPE. Low values of water absorption were observed for the biocomposites. The study showed that potato peel powder as inexpensive and potentially sustainable filler in the preparation of LLDPE biocomposites which could be biodegradable and environmentally friendly.

A study was conducted to determine the appropriate surface treatment for rice husks (RH) in polymer composite film to improve the physical properties relative to those of untreated RH/linear low-density polyethylene (LLDPE) film. Pulverized RH was treated with NaOH (RH-m) and acetic acid (RH-ac) to prepare composite films with LLDPE resin. The treated RH showed typical mercerization and acetylation, as confirmed by spectroscopic and thermal analysis methods. The RH-m sample was mercerized, allowing decomposition of hemicellulose and partially amorphous cellulose. The RH-ac sample was processed via acetylation inducing partial lignin decomposition. Field-emission scanning electron microscopy showed smaller gaps at the RH/LLDPE interface for RH-m and RH-ac compared to that with untreated RH, implying increased composite compatibility. RH-m in particular showed superior tensile strength (15.85 N/mm2), elongation (884%), Young’s modulus (60.01 N/mm2), and tear strength (7.71N/mm2) compared to untreated RH and RH-ac.

Digital image analysis (DIA) was used to achieve some information related to aspect ratio of the bubbles, bed expansion fluctuations and the emulsion area at different gas velocities and different bed heights. All experiments were done in a pseudo-2D gas-solid fluidized bed. Variations of the bubble fraction at different gas velocities and different bed heights were investigated. It was found that when the excess gas velocity increases, the dimensionless bed height increases linearly with slope of about 0.4 for LLDPE particles. To validate the analysis, the bubble diameter achieved by DIA results in this work was compared with the bubble diameter correlation presented by Shen et al. Bubble aspect ratio in different heights of the bed was extracted through image analysis, and it was observed that the bubble aspect ratio first increases with the bed height and near the freeboard becomes flattened. Results of the experiments show that the emulsion phase becomes more expanded at higher excess gas velocities. As demonstrated by the analysis results, by increasing the bed height, bubble fraction parameter is decreased.

This work aimed to prepare biodegradable thermoplastic elastomers based on NR/LLDPE/TPS ternary simple blends to achieve some exclusive properties, i.e., good biodegradability in terms of water absorption and weight loss after burial, together with reasonable mechanical and thermal properties. A comparative study on biodegradability and other related properties of NR/LLDPE binary and NR/LLDPE/TPS ternary blends was performed. It was found that increasing the TPS proportion decreased storage modulus and complex viscosity. In addition, the size of dispersed TPS domains in the NR/LLDPE co-continuous matrix increased with TPS proportion, while the mechanical properties in terms of 100% moduli, tensile strength, elongation at break, and hardness decreased. This might be attributed to decreased interfacial adhesion with increasing size of TPS domains. Furthermore, increasing the TPS loading in the blend reduced the temperatures for 5 or 50% mass loss (T5 or T50) and the degradation temperature (T d ). However, the biodegradability improved, in terms of increased water absorption and weight loss after burial in soil, with the loading level of TPS.

Untreated kenaf (KNF) and eco-friendly coupling agent (EFCA)-treated kenaf were used as filler to prepare natural fiber-reinforced polymer composites (NFPCs) using linear low-density polyethylene (LLDPE) and poly(vinyl alcohol) (PVOH) as polymer matrices. The composites containing various loadings of untreated and EFCA-treated KNF (0, 10, 20, and 40 phr) were melt-blended in an internal mixer. The effect of treatment on the behavior of processing torque, mechanical properties, morphology, functional groups, water absorption, and thermal stability of KNF/LLDPE/PVOH composites were investigated. The results revealed that EFCA-treated KNF composites exhibited higher equilibrium torque, indicating that the viscosity of molten composites increased in the presence of EFCA. The tensile strength and tensile modulus of KNF/LLDPE/PVOH composites were improved with the addition of EFCA-treated KNF attributed to the enhancement of the interfacial adhesion between KNF and LLDPE/PVOH matrices, as confirmed by field-emission scanning electron microscopy. Fourier transform infrared spectroscopy indicated the presence of ester bond in EFCA-treated KNF composites. Furthermore, EFCA-treated KNF composites possessed a lower water absorption and greater thermal stability as compared to untreated KNF composites. Therefore, EFCA could be suggested as an effective coupling agent to enhance the performance of KNF/LLDPE/PVOH composites.

Latent heat storage system by phase change materials is an effective method to achieve high density energy storage. A novel composite pellet consisted of a blend of linear low density polyethylene and low density polyethylene (LLDPE/LDPE) with low molecular weight paraffin (a phase change material, at 25 and 50 wt%) has been developed and coated by calcium silicate to prevent paraffin leakage. Three-layer coextruded films containing the paraffin composites as the middle layer have been prepared from each group for application as plastic film cover to control undesirable temperature variations during the storage of agricultural crops. The Melt Flow Index and thermal properties of the pellets as well as the quantity of paraffin leakage were studied. Thermal/morphological and permeation properties of the coextruded films have been investigated. The results showed that the LLDPE/LDPE polymer matrix provided an appropriate structural morphology for low molecular weight paraffin (n

In this work, morphology, rheological and tensile properties of low-density polyethylene/linear low-density polyethylene/thermoplastic oxidized starch (LDPE/LLDPE/TPOS) blends are studied. The blends of LDPE/LLDPE (70/30, w/w) containing 0–20 wt% TPOS in the presence of 3 wt% of PE-grafted maleic anhydride (PE-g-MA) as a compatibilizer are prepared by a twin screw extruder and then converted to appropriate thin films using an extrusion film blowing machine. Scanning electron microscopic images show that there is a relative good dispersion of oxidized starch particles in PE matrices. However, as TPOS content in the blends increases, the starch particle size increases too. The rheological analyses indicate that TPOS can decrease the elasticity and viscosity of the blends. The LDPE/LLDPE/TPOS blends show power-law behavior and as the TPOS content increases the power-law exponent (n) and consistency index (K) decrease. The ultimate tensile strength and elongation at break of the final blend films reduce, when TPOS content increases from 5 to 20 wt%. However, the required mechanical properties for packaging applications are achieved when 10 wt% oxidized starch is added, according to ASTM D4635.

Solid waste accumulation due to synthetic polymer and polymer composites used in packaging is causing a major threat to human and wildlife. Biodegradation of plastics and biocomposites in environment is a viable solution to this problem and yet a complex phenomenon due to diversity and efficiency of microbial communities involved in attacking the various biocomposite materials. The aim of the present work was to evaluate the biodegradability of biocomposites prepared from potato-peel powder together with polypropylene (POPL/PP) or linear low density polyethylene (POPL/LLDPE) plus maleic anhydride grafted polyolefin compatibilizers. To achieve this, biodegradability tests were conducted according to ASTM D 5338 on the specimen samples for 45 days. The specimens were also analysed post-biodegradation using scanning electron microscope (SEM), thermogravimetric analyser (TGA) and direct scanning calorimeter (DSC) techniques to study the changes in morphology and thermal properties. Biocomposites with 40% (w/w) POPL filler in PP without compatibilizer showed maximum degradation upto 10%, while the LLDPE composites showed biodegradation upto 1%. Addition of compatibilizers reduced the biodegradability in the composites. The results were well corroborated by percentage weight loss in the test biocomposite specimens. Biodegradation in the biocomposites was shown to be dependent on POPL content.

In the present study, the thickness of the melt resin and the thickness deviation depending on the line speed and the discharge rate were investigated to derive stable process conditions and determine the tendencies of the extrusion coating. The adhesive strength between the aluminum foil and the cast polypropylene (CPP) film, and the electrolyte resistance depending on the kinds of melt resin, were compared and analyzed to find a melt extrusion resin appropriate for pouch film manufacturing. In the extrusion coating, the line speed and the discharge rate had a significant effect on the coating thickness and deviation, as did the extrusion coating condition. Generally used melt extrusion resins (LDPE, LLDPE, PP, and PP(GMA)) showed similar adhesive strengths. Sufficient electrolyte resistance could not be obtained when only a melt extrusion resin was used. Addition of a functional resin resulted in a satisfactory level of electrolyte resistance. In particular, when FR_C was added as a functional resin, the extrusion coating showed excellent properties, including adhesive strength of 1300 gf/15 mm and good electrolyte resistance, with about 800 gf/ 15mm of adhesive strength at 85°C after seven days.

The interest of this study was to examine various kenaf (KNF) loadings and burial time, and their effects on degradability behavior of linear low-density polyethylene/poly(vinyl alcohol)/kenaf (LLDPE/PVOH/KNF) composites in soil. The LLDPE/PVOH/KNF composites with various KNF loadings were melt-mixed in a Thermo Haake internal mixer. The composites were buried in soil and their extent of degradability was assessed by tensile properties, morphological study, and weight loss and crystallinity measurements of the degraded composites. Fourier transform infrared spectroscopy was utilized to monitor the changes in chemical structure of the composites before and after degradation in soil. The results showed that with increase in KNF loading, the tensile modulus increased; meanwhile, the tensile strength and elongation-at-break of the degraded composites were dropped. Tensile properties of the degraded composites were decreased with prolonging soil burial time. The formation of cracks and pores was observed in field emission scanning electron microscope micrographs. By measuring the weight loss in LLDPE/PVOH/KNF composite samples before and after the soil burial testing and differential scanning calorimetry measurements, it was found that the weight loss and crystallinity of the composites increased with soil burial time. The degradation of the composites was confirmed by the formation of a strong absorption band assigned to carbonyl groups.