Search

Nowadays, the post-consumer polyethylene terephthalate (PET) waste from the packaging industry is one of the largest plastic waste streams worldwide. While clear PET waste is commonly recycled and is reused for textile and packaging applications (even with food contact), coloured PET waste's degraded state limits its reusing potential. This highlights the urgent need to upgrade low-value PET waste. This study focuses on enhancing coloured recycled PET (rPET) quality by introducing an epoxide chain extender (CE) from 0 to 1 wt%, to improve rheological behaviour. Simultaneously, upcycling opportunities are explored by incorporating an eco-friendly phosphorous-based flame retardant (FR) from 0 to 10 wt%, to reduce flammability and thus enabling electrical and electronic applications, among others. The impact of each additive, as well as their combination, is evaluated on the chemical structure, thermal, rheological and burning behaviour of undervalued rPET. The optimal CE content is determined at 0.8 wt%, promoting branched and higher molecular weight polymer chains. Regarding FR, 6, 8 and 10 wt% highly enhance the fire resistance. Furthermore, the combination CE/FR enables a synergistic effect, notably improving burning behaviour. Additionally, the foaming potential of the resulting high-value rPET is assessed for the first time through one-step batch foaming using supercritical CO2 as foaming agent, aiming to develop lightweight materials endowed with superior burning behaviour. The material containing 0.8 wt% CE reaches the lowest density (200 kg/m3) and a closed cellular structure with smaller cell diameters (8 ± 3 μm). Meanwhile, the combination of 0.8 wt% CE and 6 wt% FR gives rise to a foamed material with density of 659 kg/m3 and cell diameter of 7 μm. Thus, this batch procedure in one-step enables the formation of microcellular foams based on coloured rPET (cell size below 10 μm). [ABSTRACT FROM AUTHOR]

The consumption of poly(ethylene terephthalate) (PET) has experienced a surge in recent times, owing to the widespread use of single-use plastic bottles, particularly in the context of beverages and drinking water. PET, a thermoplastic polymer, is known for its recyclability, and the recycled variant is referred to as rPET. The incorporation of rPET in fiber manufacturing is favored due to its cost-effectiveness, and the functionalized rPET fibers present an innovative product that can be used in a variety of applications. This study aimed to functionalize rPET fibers using the spun-bond technique, imparting antibacterial and flame-retardant properties, which are commonly employed in thermal insulator products. Nano zinc oxide (nano-ZnO) was used to confer antibacterial functionality, while phosphorus flame retardant (PFR) was used to impart flame-retardant properties. The core-sheath bicomponent fiber structure was employed to achieve the desired outcomes. The extrusion process was used to incorporate PFR and ZnO as the core and sheath components, respectively, at various ratios. The presence of nano-ZnO on the fiber shell was confirmed by the EDX data. The flame retardant study was utilized to observe the level of burning damage. The findings of the study demonstrated that increasing the percentage of PFR (maximum 8%) resulted in a significant decrease in the damage distance of the nonwoven material, with reductions of up to 60% was observed. Furthermore, the results of the antibacterial test indicated that the inclusion of an additional 3 wt% of ZnO resulted in a considerable reduction of the bacteria S. aureus and K. pneumoniae by about 99.96 and 98.79%, respectively. Based on the results obtained, it was determined that the most effective functionalized fiber was synthesized by including 3 wt% of ZnO and 5 wt% of PFR. Moreover, the incorporation of varying proportions of additives resulted in modifications to the mechanical and thermal characteristics of the fibers. This work highlights the potential of functionalized rPET bicomponent fibers as viable candidates for thermal insulator products. The utilization of functionalized rPET bicomponent fibers as a sustainable alternative for thermal insulator products showcases the commitment to environmentally friendly solutions, contributing to the overall goal of sustainability in the manufacturing industry. [ABSTRACT FROM AUTHOR]

In this study, graphene‐loaded electrospun recycled poly(ethylene terephthalate) (rPET) nanofibrous mats were produced and characterized morphologically, spectrally, mechanically and thermally. Particularly, the effects of graphene nanoplatelets (GNP) and multilayer graphene (GML) in improving the thermal conductivity and heat dissipation abilities of rPET‐based composite nanofibers were investigated. The morphological analyzes pointed out that 1% graphene loading led to smooth nanofibers while 5 and 10% of GNP‐loading resulted in coarser nanofibers with rougher surfaces and agglomerations. The differential scanning calorimetry results pointed out that the crystallization temperature increased with increasing graphene content as a result of the pronounced nucleation effect. The thermogravimetric analysis demonstrated an improvement in the thermal stability of the composite nanofibers. The thermal conductivity coefficients increased to 25.422 W/mK‐35.842 W/mK for rPET/GNP nanofibers and up to 62.669 W/mK for rPET/GML nanofibers, compared to that of 12.753 W/mK for neat rPET nanofibers which correspond to an increase between 99 and 391%. Heat dissipation capability of the graphene‐loaded composite nanofibers was illustrated with infrared thermography data, displaying an increase in the average surface temperature of the nanofibrous mats between 2 and 19°C at 30 s of heating. The results suggest the use of the graphene‐loaded rPET composite nanofibers as textile materials for thermoregulating applications. Highlights: Recycled poly(ethylene terephthalate)/graphene composite nanofibers are electrospun.Thermal conductivity of graphene‐loaded nanofibers increases by up to 391%.Graphene loading in nanofibers leads to faster and more uniform heat dissipation.Mechanical properties of composite nanofibers improve.Value‐added recycled polyester materials for thermal management are foreseen. [ABSTRACT FROM AUTHOR]

Antistatic packagings are very important for proper transportation and storage of electronic components since these components can be damaged with electric overloads generated through rubbing. Therefore, the purpose of this study was to develop an innovative material for antistatic packaging with a sustainable character. For this, a blend of recycled poly(ethylene terephthalate) (PET), polycarbonate (PC), and polyaniline (PAni) was prepared by melt extrusion. Samples have a final content of 68 wt% of PET, 29 wt% of PC, and 3 wt% of PAni doped with cobalt (PAni-Co). The properties were determined by differential scanning calorimetry, thermogravimetric analysis, tensile testing, electrical resistivity analysis, and Fourier transform infrared spectroscopy. To the best of our knowledge, no previous work studied the incorporation of PAni-Co in PET/PC blend. [ABSTRACT FROM AUTHOR]

Recently the synthesis and application of bio-based composite materials, which contain polymeric and inorganic units such as TiO 2 , has gained much attention in the field of water/wastewater treatment, due to their better (and more practical) performance parameters. In the present study, recycled poly(ethylene terephthalate) (PET) has been used and evaluated as supporting polymer for Aeroxide P25 TiO 2 immobilization. PET-TiO 2 composite films were synthesized at different TiO 2 content (10%, 30% and 47% TiO 2) and characterized with different techniques such as X-ray Powder Diffraction (XRD), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Scanning electron microscopy (SEM), etc. The photocatalytic activity of the new (synthesized) bio-based TiO 2 composite films was investigated under simulated solar irradiation for the degradation of a mixture of antibiotic pharmaceuticals (Isoniazid, Metronizadole, Sulfadiazine, Sulfamethoxazole, Trimethoprim, Norfloxacin, Moxifloxacin and Lincomycin). The immobilization of TiO 2 was successful in all cases and by increasing the photocatalyst concentration results in higher photocatalytic efficiencies. The new composite films were tested two times to assess their reusability, which found to be better for PET-10%-TiO 2 composite films; therefore the latter has been used for further investigation thus exhibiting good stability even after five cycles. The results showed that PET-10%-TiO 2 was efficient in degrading the antibiotic mixture in water and in wastewater matrix. • The photocatalytic activity of novel biobased-PET-TiO 2 composite films was tested. • XRD, TGA, DSC, SEM characterizations were performed. • At higher TiO 2 loading, reusability of the photocatalysts decreased. • PET-10% wt TiO 2 exhibited high performance even after 5 cycles. • Antibiotics degradation was achieved in water and wastewater matrix. [ABSTRACT FROM AUTHOR]

Recycled poly(ethylene terephthalate) (R-PET)/high-density polyethylene (HDPE)/glycidyl methacrylate grafted poly(ethylene-octene) (mPOE) blends, in which the binary (HDPE/mPOE) dispersed phase was of a HDPE core-mPOE shell structure, were prepared. For this purpose, HDPE-g-mPOE graft copolymers were prepared in HDPE/mPOE blends via reactive extrusion with the presence of the free radical initiator dicumyl peroxide (DCP). Then, R-PET was blended with the HDPE/mPOE blends by melt extrusion. The effect of the DCP and mPOE content in the HDPE/mPOE blends on the phase morphology and mechanical properties of the R-PET/HDPE/mPOE blends were studied systematically. It was found that the blends containing reactive compatibilizer exhibited the encapsulation of the HDPE by the mPOE, forming core–shell particles dispersed phase morphology. The graft chains of HDPE-g-mPOE-g-PET formed by the in situ reaction between R-PET and mPOE phases reduced the interfacial tension. Consequently, the dispersed phase morphology was observed to form smaller diameter core–shell particles. The resultant blends exhibited an effect on both the thermal and mechanical properties. Differential scanning calorimetric analysis showed the dispersed phase particles could act as a nucleating agent in the R-PET matrix to improve the crystallization temperature, while the graft copolymers formed in the compatibilized R-PET/HDPE/mPOE blend decreased the nucleation activity. Notched Charpy impact strength and elongation at break of the R-PET were improved by forming the core–shell particles dispersed phase morphology. [ABSTRACT FROM AUTHOR]

The glycolysis of poly(ethylene terephthalate) (PET) by diethyleneglycol (DEG) in the presence of acetate catalyst usually produces a dark color product. Various catalysts have been used, but only ZnSO4·7H2O gives a bright yellowish liquid material. In addition, after the reaction the catalyst ZnSO4·7H2O can be separated easily and reused. Under microwave irradiation, the PET glycolysis is more efficient in time, conversion, and color improvement. The reaction mixture was purified by treatment with 20% sodium chloride solution. The structure of the isolated products was confirmed by FTIR, NMR, and HPLC-MS. Condensate of the volatile material from the glycolysis reaction was also isolated and analyzed by GC-MS. The mechanisms of PET degradation by DEG and side product formation were proposed. The transesterification of PET with excess DEG was strongly competed by the degradation of DEG to form dioxane and acetaldehyde as main volatile side products and by ether formation; therefore, the using of excessive DEG was unfavorable for the PET glycolysis. [ABSTRACT FROM AUTHOR]

The mechanical and interfacial properties were evaluated for carbon fiber reinforced composites (CFRC) manufactured using thermally recycled waste carbon fiber and recycled polyethylene terephthalate (PET). The mechanical properties of the recycled fiber were determined and compared to those of neat fibers using the single-fiber tensile test. The surfaces of the recycled and neat carbon fiber were examined and compared using FE-SEM and dynamic contact angle measurements. A goal of the study was to determine the applicability of industrial use of recycled CF and/or recycled PET in CFRC. Mechanical properties were measured using short beam and tensile tests. These properties were observed to be correlated with crystallinity. The interfacial properties between the recycled carbon fibers and recycled PET were evaluated using the microdroplet test. At low temperature residual resin remained on the recycled CFs surface resulting relatively the low interfacial properties. At excessively high temperatures, oxidation occurred, on the CFs surface, which also resulting in relatively poor low mechanical properties. The optimal treatment condition was 500 °C, where the surface was relatively clean and the reduction in mechanical properties was minimized. [ABSTRACT FROM AUTHOR]

Compatibilizer plays very important roles in preparing high performance polymer composites, not only for the ternary immiscible polymer blends, but also for the recycled and reused of waste plastics mixture. Generally, the compatibilizers can be used as the toughening agent in blending polymer materials. In the present work, the poly(styrene- b-(ethylene- co-butylene)- b-styrene) (SEBS) or maleic anhydride-grafted poly(styrene- b-(ethylene- co-butylene)- b-styrene) (SEBS- g-MA) acts as the compatibilizer and toughening agent for the preparation of R-PET/LDPE/SEBS (70/20/10) ternary blends. It must be pointed that the ternary blends are costlessly and conveniently prepared from the recycled poly(ethylene terephthalate) (R-PET) and linear low density polyethylene (LLDPE) through a melt blending in a co-rotating twin-screw extruder and injection moulded. The morphologies of the ternary blends are characterized by scanning electron microscopy (SEM). It was found that the blends contains reactive or non-reactive compatibilizer, the morphology originates from the LLDPE particles encapsulated by both SEBS and SEBS- g-MA. So, it results to the reduced interfacial tension between of the R-PET and SEBS- g-MA, in which the grafted chains of PET- g-SEBS- g-MA formed through in situ reaction between R-PET and SEBS- g-MA phases. Therefore, core-shell particles with smaller diameter disperse uniformly in the blends. Moreover, the good compatibilization and corresponding morphologies induce in balanced mechanical and thermal properties. DSC analysis show the dispersed phase particles could act as nucleating agent in the R-PET matrix, which results the improvement of the crystallization temperature. And it was also observed the decreased nucleation activity in graft copolymers in the R-PET/LLDPE/SEBS- g-MA blends. Notched Charpy impact strength and elongation at break are improved by the addition of compatibilizer. [ABSTRACT FROM AUTHOR]

Recycled poly(ethylene terephthalate) (R-PET) was partially replaced with halloysite nanotubes (HNTs) as fillers in natural rubber (NR) composites. The composites were prepared by incorporating hybrid filler into NR using a laboratory size two-roll mill. The total amount of hybrid filler in each formulation was kept constant at 20 phr. Results revealed that scorch time, cure time, maximum torque, cross-link density and thermal stability increased with the replacement of R-PET by HNTs. Due to its reinforcing effect and ductility of the HNTs, the moduli, tensile strength, elongation at break and fatigue life were found to increase consecutively with increasing HNTs content. Morphological study of the tensile fracture surfaces of the composites exhibited that HNTs has better adhesion and is well-dispersed in NR matrix as compared to R-PET particles. However, R-PET exhibited positive effect by reducing the curing time of the hybrid NR composites. [ABSTRACT FROM AUTHOR]

Recycled poly(ethylene terephthalate) (R-PET) and virgin polyamide 6 (PA6) blends compatibilized with glycidyl methacrylate grafted poly(ethylene-octene) (POE-g-GMA) were melt blended. The morphological, rheological and mechanical properties of the prepared blends were investigated by scanning electron microscopy, rheology, and an electromechanical testing instrument, respectively. All of the blends showed a droplet dispersion type morphology, and the PA6 particle size decreased with increase in the POE-g-GMA concentration. The storage modulus (G′), loss modulus (G′′), and complex viscosity (η*) of the blends significantly increased at low frequency with the addition of POE-g-GMA. In addition, ‘‘Cole-Cole’’ plots showed that the elasticity of the blends was also increased by raising the compatibilizer dosage. It was also found that 10 wt% of POE-g-GMA caused 88.46 and 171.05% increments in Charpy impact strength and elongation at break with only a 21.66% decrement in tensile strength. [ABSTRACT FROM AUTHOR]

This study presents the mechanical and thermal properties of environment-friendly composites made from recycled newspaper fibers reinforced recycled poly(ethylene terephthalate) (rPET) resin with the addition of styrene-ethylene-butylene-styrene grafted maleic anhydride (SEBS-g-MA) as compatibilizer. The effect of SEBS-g-MA addition (i.e., 10 phr) by using a twin-screw extruder to the rPET resin, followed by different fiber content (5, 10 and 15 wt.%) on the tensile, flexural and impact properties of the composites were determined. Stiffness of composites increased significantly compared to those of rPET/SEBS-g-MA blend. Fiber addition resulted in moderate increases in both tensile and flexural strength of the composites. Scanning electron microscope (SEM) photomicrographs of the impact fracture surfaces demonstrate good adhesion at 5 and 10 % fiber content. Differential scanning calorimetry (DSC) showed that the presence of newspaper fibers enhanced the nonisothermal crystallization kinetics and crystallinity. Thermal stability of the composites was improved as indicated by thermogravimetric analysis (TGA). [ABSTRACT FROM AUTHOR]

The partial replacement of recycled poly(ethylene terephthalate) (R-PET) powder by the commercial fillers namely carbon black (N550), halloysite nanotubes (HNTs) and silica in natural rubber composites were carried out. The fatigue life, thermogravimetric analysis, and morphology of natural rubber composites were investigated. Results indicated that the replacement of R-PET by commercial fillers increased the fatigue life of the composites where NR/R-PET/N550 composites showed superior fatigue life followed by NR/R-PET/HNTs and NR/RPET/ Silica composites. Replacement of R-PET with commercial fillers improved the thermal stability of the natural rubber composites where NR/R-PET/HNTs system exhibits higher decomposition temperature than those of NR/R-PET/ N550 and NR/R-PET/HNTs composites respectively. SEM micrographs of the composites are in good agreement with the fatigue life observed whereby more roughness and matrix tearing lines indicating higher energy is required to cause a failure of the composites. [ABSTRACT FROM AUTHOR]

Abstract: In petroleum wells, the granular sand control agents commonly employed are basically inorganic compounds, which are used in operations to prevent the production of sand, from unconsolidated sandstone formations, that contaminates the produced hydrocarbons. In this work the viability of applying recycled poly(ethylene terephthalate) (PETrec) as sand control agent, in an environment that simulated the conditions of the wells, was evaluated. Virgin PET (PETvir) was tested as a standard for comparison means. Pellets of each polymer (PETrec and PETvir) were confined into metallic cells filled with sea water or petroleum, under conditions observed in some sandstone formations that are normally subjected to sand control, in Campos Basin (Rio de Janeiro, Brazil). The cells systems were submitted to a controlled temperature of 70 °C and pressure of 24.1 MPa, and rolled during the experiment period. The total exposure time was approximately six months (172 days), with scheduled sampling periods. Thermal, mechanical and granulometric properties of the pellets before and after the exposition were evaluated. The samples were characterized by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TG). Mechanical experiments were performed, in order to determine the grain pack permeability, by the end of the exposition period, according to API RP 58 and API RP 61 standard methods. Particle size of the grains, before and after the exposure process, was compared. Test results showed that PETrec and PETvir samples did not present significant physical changes or evidences of degradation, nor in water neither in petrol, suggesting that the use of recycled PET as sand control agent seemed to be viable within the experiment conditions. [Copyright &y& Elsevier]

Recycled poly(ethylene terephthalate) (R-PET) was blended with 15-30 wt% of styrene-ethylene/butylenes-styrene (SEBS) block copolymer and maleic anhydride grafted SEBS (SEBS-g-MA). Effects of nucleation and toughening of the elastomers were evaluated systematically by study of morphology, crystallization, thermal and mechanical properties of the blend. The addition of 30 wt% SEBS promoted the formation of co-continuous structure of the blend and caused the fracture mechanism to change from strain softening to strain hardening. Addition of SEBS-g-MA resulted in significant modification of phase morphology and obviously improved the impact strength. The compatibilization reaction of PET with SEBS-g-MA accelerated the crystallization of PET and increased the crystallinity. The shifts in glass transition temperature of PET towards that of SEBS-g-MA and the higher modulus for R-PET/SEBS-g-MA (70/30) blend found by DMA are also indications of better interactions under the conditions of compatibilization and interpenetrating structure. [ABSTRACT FROM AUTHOR]

High toughness recycled poly(ethylene terephthalate) (R-PET)/poly(ethylene-octene) (POE) blends were prepa scanning electron microscopy red by adding glycidyl methacrylate grafted poly(ethylene-octene) (mPOE) as reactive compatibilizer. Evidence for reaction between the carboxyl or hydroxyl end groups of R-PET and the epoxy groups of mPOE under the conditions of processing to form graft copolymers (PET-g-mPOE) is presented. Effects of compatibilizer on morphology and mechanical and thermal properties of the blends were evaluated systematically. The results showed that dispersed phase particle size decreased with increasing mPOE content until the critical compatibilizer concentration (5 wt%) was reached. Notched Charpy impact strength and elongation at break were improved greatly by the addition of compatibilizer. Differential scanning calorimetry (DSC) analysis showed POE could act as a nucleating agent in the R-PET matrix to improve the crystallization temperature, while the graft copolymers formed in compatibilized R-PET/POE blends decreased the nucleation activity. [ABSTRACT FROM AUTHOR]

Abstract: Polymeric methylene diphenyl diisocyanate (PMDI) was added as chain extender to a blend of recycled poly(ethylene terephthalate) (R-PET) and linear low density polyethylene (LLDPE) with compatibilizer of maleic anhydride-grafted poly(styrene–ethylene/butadiene–styrene) (SEBS-g-MA). Hydroxyl end groups of PET can react with both isocyanate groups of PMDI and maleic anhydride groups of SEBS-g-MA, which are competing reactions during reactive extrusion. The compatibility and properties of the blends with various contents of PMDI were systemically evaluated and investigated. WAXD results and SEM observations indicated that chain extension inhibits the reaction between PET and SEBS-g-MA. As the PMDI content increased, the morphology of dispersed phase changed from droplet dispersion to rodlike shape and then to an irregular structure. The DSC results showed that the crystallinity of PET decreased in the presence of PMDI, and the glass transition temperature (T g) of PET increased with addition of 0–0.7w% PMDI. The impact strength of the blend with 1.1w% PMDI increased by 120% with respect to the blend without PMDI, accompanied by only an 8% tensile strength decrease. It was demonstrated that the chain extension of PET with PMDI in R-PET/LLDPE/SEBS-g-MA blends not only decreased the compatibilization effect of SEBS-g-MA but also hindered the crystallization of PET. [Copyright &y& Elsevier]

Abstract: This paper reports on a study of composites of recycled poly(ethylene terephthalate) (PETr) and sugarcane bagasse fiber with and without compatibilizing agents. The interfacial behavior of these composites was investigated by torque rheometry, tensile tests, dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). A comparison of the torque values resulting from the use of ethylene/n-butyl acrylate/glycidyl methacrylate (EBGMA) and ethylene–methyl acrylate (EMA) copolymer compatibilizing agents indicated that EBGMA increased the interaction between the constituents more effectively than EMA. The addition of bagasse sugarcane fiber did not affect the tensile modulus and reduced the tensile strength and elongation of PETr, as is normally observed in these types of composites. Consistent with the results of torque rheometry and DMA, the SEM analyses indicated that EBGMA improved adhesion between the constituents. All the composites showed promise as good alternatives for the production of environmentally friendly products. [Copyright &y& Elsevier]

Recycled poly(ethylene terephthalate) (r-PET) was blended with poly(ethylene octene) (POE) and glycidyl methacrylate grafted poly(ethylene octene) (mPOE). The nonisothermal crystallization behavior of r-PET, r-PET/POE, and r-PET/mPOE blends was investigated using differential scanning calorimetry (DSC). The crystallization peak temperatures (Tp) of the r-PET/POE and r-PET/mPOE blends were higher than that of r-PET at various cooling rates. Furthermore, the half-time for crystallization (t1/2) decreased in the r-PET/POE and r-PET/mPOE blends, implying the nucleating role of POE and mPOE. The mPOE had lower nucleation activity than POE because the in situ formed copolymer PET-g-POE in the PET/mPOE blend restricted the movement of PET chains. Non-isothermal crystallization kinetics analysis was carried out based on the modified Avrami equation, the Ozawa equation, and the Mo method. It was found that the Mo method provided a better fit for the experimental data for all samples. The effective energy barriers for nonisothermal crystallization of r-PET and its blends were determined by the Kissinger method. [ABSTRACT FROM AUTHOR]

Abstract: Blends of recycled poly(ethylene terephthalate) (R-PET) and linear low density polyethylene (LLDPE) were compatibilized with poly(styrene-ethylene/butyldiene-styrene) (SEBS) and maleic anhydride-grafted poly(styrene-ethylene/butyldiene-styrene) (SEBS-g-MA). Effects of compatilizer were evaluated systematically by study of mechanical, thermal and morphology properties together with crystallization behavior of PET. Tensile properties of the blends were improved effectively by the addition of 10wt% SEBS-g-MA, elongation at break and charpy impact strength were increased with the increasing content of compatilizer. SEBS-g-MA is more effectual on mechanical properties of R-PET/LLDPE blends than SEBS. DSC analysis illustrates crystallinities of PET and LLDPE were increased by compatilizer at annealing condition. WAXD and FT-IR spectra show that annealing influences crystallization behavior of PET. Different compatilizer content results in different morphology structure, in particular, higher SEBS-g-MA content can induce the formation of a salami microstructure. [Copyright &y& Elsevier]

Calcium terephthalate anhydrous salts (CATAS), synthetized by reaction of terephthalic acid with metal (Ca) oxide were incorporated at different weight contents (0–30 wt. %) in recycled Poly(ethylene terephthalate) (rPET) by melt processing. Their structure, morphology, thermal and mechanical properties (tensile and flexural behavior) were investigated. Results of tensile strength of the different formulations showed that when the CATAS content increased from 0.1 to 0.4 wt. %, tangible changes were observed (variation of tensile strength from 65.5 to 69.4 MPa, increasing value for E from 2887 up to 3131 MPa, respectively for neat rPET and rPET_0.4CATAS). A threshold weight amount (0.4 wt. %) of CATAS was also found, by formation at low loading, of a rigid amorphous fraction at the rPET/CATAS interface, due to the aromatic interactions (π−π conjugation) between the matrix and the filler. Above the threshold, a restriction of rPET/CATAS molecular chains mobility was detected, due to the formation of hybrid mechanical percolation networks. Additionally, enhanced thermal stability of CATAS filled rPET was registered at high content (Tmax shift from 426 to 441 °C, respectively, for rPET and rPET_30CATAS), essentially due to chemical compatibility between terephthalate salts and polymer molecules, rich in stable aromatic rings. The singularity of a cold crystallization event, identified at the same loading level, confirmed the presence of an equilibrium state between nucleation and blocking effect of amorphous phase, basically related to the characteristic common terephthalate structure of synthetized Ca–Metal Organic Framework and the rPET matrix. [ABSTRACT FROM AUTHOR]

The present research aims at imparting an improved wicking ability to the recycled multifilament yarns by wrapping composite nanofibers to attain an efficient material for filtration purposes. Therefore, polyacrylonitrile nanofibers containing dimethyl 5‐sodium sulfoisophthalate nanoparticles were wrapped around the recycled poly(ethylene terephthalate) yarn by means of a novel electrospinning technique. Several tests were performed to investigate the parameters affecting wicking rise and moisture regain of the samples. Taguchi method was used in two separate designs (with or without nanoparticles). Some factors such as polymer solution concentration, mass ratio of nanoparticles, take‐up rate, and number of filaments were considered as the variable factors while yarn wicking rate and moisture regain were the response factors. It was found that the hydrophilic nature of nanoparticles together with the ultrafine structure of nanofibers provide yarns with enhanced wicking properties. Although solution concentration is the predominant factor in wicking rate of the yarns containing nanoparticles, the most effective factor in wicking rise and moisture regain for other cases is the number of filaments. The mechanism of nanoparticle effect on fluidic jet during electrospinning process is explained by theory of nanofluids stability which has never been validated experimentally in previous research studies. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48185. [ABSTRACT FROM AUTHOR]

Recycled poly(ethylene terephthalate) (PET), subjected to the treatment with the flame retardant first, was used to reinforce the rigid polyurethane foams (RPUFs). Different loadings of PET fibers (3–12 wt %) of different lengths (5, 10, 15, and 20 mm) were added into RPUF. The mechanical properties of composites were studied by compressive strength test and shear stress test. The flame‐retardant properties were evaluated by cone calorimeter and limited oxygen index test. The results showed that the proper addition of PET fibers could improve the mechanical and flame‐retardant properties of the material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47758. Compressive strength of RPUF containing various fibers. [ABSTRACT FROM AUTHOR]