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Epoxy syntactic foams (SF) filled with hollow glass microspheres (HGM) were prepared by simple resin casting method and characterization in this study. The effect of varying the amount of HGM on the specific mechanical and water absorption properties of SF composites were investigated. Five different composition of SF (SFT60-0.5 to SFT60-2.5) were compared with the neat epoxy matrix. The wall thickness of the microballoons differ because of its different percentile size distribution (10th, 50th and 90th), which reflects in its density variation. The results show that the specific tensile and flexural strength increases with an increasing filler (HGM) content. The density of SF filled with HGM reduces with increasing volume fraction of filler content. Scanning electron microscopy was done on the failed samples to examine the fractured surfaces. The water absorption capacity of the SF was also investigated as it relates to the HGM volume fraction variation. All the syntactic foam composition shows a better diffusion coefficient capacity than the neat epoxy resin. This makes it applicable in structural purposes and several marine application products such as Autonomous Ultimately Vehicle (AUV).

This paper explores the effect of nanoclay as improvement to the interfacial properties of starch bioplastic material filled with cellulose-nanoparticles (CNPs). At the initial, cornstarch bioplastics filled with CNPs were prepared. The CNPs were prepared through acid-hydrolysis process by using acid concentration to break the amorphous region of chopped fiber to produce nano-cellulose. Various CNPs concentration (0.5–2.5 wt.%) were dispersed in cornstarch biopolymer matrix. Cornstarch bioplastic reinforced with 1.5 wt.% of CNPs showed optimum improvement in thermal and mechanical properties. Furthermore, nanoclay (NC) of varying weight percentage (0.1–0.5 wt. %) were added to the optimum improved 1.5 wt.% CNP/cornstarch biopolymer material solution. Hence, cellulose-nanoparticles/nanoclay (CNPs/NC) reinforced cornstarch bioplastic films were formed by solution casting method.

The objective of this work is to improve the structural characteristics of hollow glass microsphere (HGM) filled epoxy syntactic foam composites with little voids content and improved HGM dispersion in the composite. A modified degassing technique has been introduced during resin casting process of the HGM filled syntactic foam composites. The effect of HGM content volume fractions (5–25%) on the degassing techniques was examined. The syntactic foam composites were characterized by analysing structural morphology using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy(TEM), and density measurements (theoretical and experimental). Less than 5% void content has been achieved in this study. This resulted in improved tensile and dynamic mechanical properties (DMA).

Crystal structure analysis of N-[2-(4-fluoro-3-phen­oxy­benzo­yl)hydrazinecarbo­thio­yl]benzamide and its 4-meth­oxy derivative highlights the significance of strong and weak hydrogen bonds. The difference in the contributions of atom–atom contacts obtained from Hirshfeld surface analysis and fingerprint plots helps in distinguishing the variations in the crystal packing of the two compounds., The compound N-[2-(4-fluoro-3-phen­oxy­benzo­yl)hydrazinecarbo­thio­yl]benzamide, C21H16FN3O3S, crystallizes in the monoclinic centrosymmetric space group P21/c and its mol­ecular conformation is stabilized via an intra­molecular N—H⋯O hydrogen bond. The corresponding para-meth­oxy derivative, namely, N-[2-(4-fluoro-3-phen­oxy­benzo­yl)hydrazinecarbo­thio­yl]-4-meth­oxy­benzamide, C22H18FN3O4S, crystallizes in the monoclinic centrosymmetric space group C2/c. The supra­molecular network mainly comprises N—H⋯O, N—H⋯S and C—H⋯O hydrogen bonds, which contribute towards the formation of the crystal structures for the two mol­ecules. The different inter­molecular inter­actions have been further analysed using Hirshfeld surface analysis and fingerprint plots.

This work focused on studying the behaviour of thermo-mechanical properties of kenaf fibre-reinforced polylactic acid (PLA) biocomposites infused with clay nanoparticles. Kenaf/PLA biocomposites infused with different nanoclay contents of 0, 3, 5 and 7%wt with respect to PLA were fabricated using resin casting method. Thermo-mechanical properties were investigated using thermogravimetric analyser (TGA) and dynamic mechanical analysis (DMA). TGA results showed an improvement in the thermal stability of the biocomposites as nanoclay content was increased due to thermal barrier effects of nanoclays. DMA results showed that storage and loss moduli increased with increase in nanoclay content up to 5%wt nanoclay loading after which a reduction was observed, whilst tandelta gradually decreased with increase in nanoclay content. The glass transition temperature (Tg) of the biocomposites reduced with increase in nanoclay content. This was due to nanoclays which infused themselves into the biocomposite phase structure improving crystallinity. Tg also reduced due to agglomeration effects at high nanoclay loading. Consequently, the infusion of clay nanoparticles into kenaf/PLA biocomposites improved the thermo-mechanical properties of the biocomposites. Optimum improvements were achieved with 5%wt nanoclay loading.

In this study, the possibility of producing layered silicate-reinforced acrylonitrile butadiene styrene (ABS) using additive manufacturing procedures was investigated. In particular, this investigation presents novel methods for making nanoclay-infused acrylonitrile butadiene styrene composite spur gear. The gear was developed by introducing different weight percentages of nanoclay (0–5 wt%), on each acrylonitrile butadiene styrene layer. A square panel of 6 layers with varying proportions of nanoclay was fabricated using a 3D printer. The effect of nanoclay loading on the mechanical properties such as impact, tensile, flexural, and DMA of spur gears created using pure acrylonitrile butadiene styrene and nanoclay-infused nanocomposite was investigated and compared. The strength of the developed spur gear varies with different loading of nanoclay. The results that the spur gear, with 2 wt% nanoclay, offered superior properties. The micrographs showed the dispersion of nanoclay strongly bonded with the matrix, resulting in improved strength and stiffness. The improvement in mechanical properties depicts the effectiveness of additive manufacturing procedure with an enormous benefit for the mass production of gears of different types.

A comprehensive inspection of crystal packing of a series of four (5-chloro-2-((3-phenyl-1,2,4-oxadiazol-5-yl)methoxy)phenyl)methanone derivatives, containing biologically active 1,2,4-oxadiazol moiety, have been performed to investigate the functional role of non-covalent interactions in their supramolecular architectures. The compounds of interest are (5-chloro-2-((3-(4-iodophenyl)-1,2,4-oxadiazol-5-yl)methoxy)phenyl)(phenyl)methanone, C22H15O3N2ICl, OX-1, (5-chloro-2-((3-(3-chloro-4-fluorophenyl)-1,2,4-oxadiazol-5-yl)methoxy)phenyl)(phenyl)methanone, C22H14O3N2Cl2F, OX-2, (5-chloro-2-((3-(4-isopropylphenyl)-1,2,4-oxadiazol-5-yl)methoxy)phenyl)(phenyl)methanone, C25H21O3N2Cl, OX-3, (5-chloro-2-((3-(4-ethoxyphenyl)-1,2,4-oxadiazol-5-yl)methoxy)phenyl)(phenyl)methanone, C24H20O4N2Cl, OX-4. Title compounds were synthesized and subsequently characterised using the single crystal X-ray diffraction technique. In the crystal environment, the molecular conformations of all the four derivatives have been found to be stabilized via O⋯C [lone pair (lp)-π interaction] contacts. Detailed supramolecular structural analysis depicts an important role of lp-π interactions and halogen bonds in the crystal packing of all four derivatives in addition to the presence of favourable C-H⋯O, C-H⋯N, C-H⋯F and C-H⋯Cl hydrogen bonds. Furthermore, the electrostatic potential map provides a deeper insight to the nature of lp-π and halogen bonding interaction. The fingerprints plots associated with Hirshfeld surface were also analysed to evaluate the quantitative contribution of atom-atom contacts toward the formation of solid-state architectures. The quantitative analysis of the interaction energies associated with the molecular pairs involving lp-π and halogen bonding interactions has also been performed to get a deeper insight into the role of such interactions towards the overall stabilization of the crystal lattice.

The objective of this work was to prepare a natural fiber reinforced composite product by using nanoparticle technique method. Nanoclay particles were infused into the banana fiber and these modified banana fibers were then reinforced in epoxy polymer composites. A short banana fiber reinforced epoxy polymer composite cylinder was prepared by resin impregnation method, and the compressive, tensile, interfacial and energy absorption characteristics were studied. The properties of nanoclay infused banana fiber reinforced composites were compared with alkaline (NaOH) treated and untreated banana fiber reinforced epoxy composites. It was observed that the nanoclay infused banana fiber composites has resulted in 17%, ∼2 times and 43% improved compressive yield stress, modulus and strength when compared with untreated banana fiber reinforced epoxy composite cylinder. However, nanoclay infusion induces brittleness into the fiber affecting the elongational properties. Tensile, flexural and short beam properties show that the reinforcement effect of nanoclay was higher in flexural and short-beam modes when compared with tensile mode, due to higher level of surface interaction of nanoclay particles in flexural and short-beam modes. About 2 times improved energy absorption properties were obtained in nanoclay infused banana fiber reinforced epoxy composites when compared with untreated banana fiber reinforced epoxy composites. Microscopy examination revealed that the nanoclay infusion in fiber improved fiber-matrix interfacial and load transfer characteristics leading to the higher level of property improvement in nanoclay infused banana fiber reinforced epoxy composites. The outcome of the result suggest that the nano-technique is very much useful and can be simply applied onto the natural fibers to realize the potential application of these materials.

Carbon black (CB)-filled polylactic acid (PLA) composites attract a significant interest due to their superior structural and functional performances. Properties of CB-filled PLA composites depend on physical and chemical interactions in them. In this study, interactions within CB (N220)-filled PLA composites as a function of processing method, filler concentration, and their effect on mechanical properties are investigated via mechanical tests. Strong interface interaction at intermediate concentration of 2.5 wt.% CB with PLA was confirmed through mechanical tests. Moreover, a 2.5 wt.% of CB-formed networks within PLA composites, which added the fracture resistance in the weaker phase, thereby improving their mechanical properties. Beyond 2.5 wt.%, a linked skeletal grid was formed, enhancing the fracture path in a weaker phase and deteriorating the mechanical properties. Experimental results on density and elastic modulus were compared with the theoretical model predictions. This study gives an insight on interactions controlling physical and mechanical properties related to various processing techniques and weight percent of CB in PLA composites.

This research focuses on the mechanical and effect of oil absorption on the tribological properties of carbon-based brake pad material (CBP). Carbon-based materials, including those at a nanosize, are combined for developed brake pad material. The mechanical properties related to wear properties such as compression strength, stiffness, hardness, and absorption properties were determined. The effect of oil absorption on the tribological properties of carbon-based materials was investigated. The obtained properties are compared with that of a ceramic-made brake pad (commercial). The experimental results show that the mechanical and absorption properties of the developed brake pad material varied with the combination and quantity of additives used to develop each brake pad material. CBP material offered higher performance than ceramic-made brake pads. The CBP material showed a higher shear strength of about 110%, 51% enhanced compressive strength, 35% greater modulus, comparative statistical hardness, 98% lesser water intake, and 97% oil absorption rate than ceramic made brake pad. The tribological properties of friction material after soaked in oil proved that absorption properties affect tribological properties of brake pads, which can be attributed to the oil content in the material system. The effect of oil uptakes on wear rate and friction of the commercial brake pad was higher than CBP materials, implying that the loading of carbon-based materials is a viable way to reduce absorption rate, which helps in increasing brake pad performance. The improved properties are suggestive of materials combinations that may be used to develop brake pad materials.

This chapter reviews the recent progress in tribological properties of 3D printed polymer nanocomposites and their applications. The printing of thermoplastic composite infused with different sizes of particles was reviewed. The processing of creating a 3D printed nanoparticle reinforced nanocomposite and their structure-property relations were discussed—valid information on several abrasion apparatus for tribological investigation was also provided. The influence of loading particles on the wear resistance and frictional behaviors of 3D printed nanoparticle reinforced nanocomposites were review. Similarly, the effect of applied load, speed (RPM), and sliding distance on the wear resistance and frictional behaviors of pure thermoplastic, including particle-filled composite, were also evaluated. The tribological properties concerning wear and friction were evaluated. The current application of 3D printed nanoparticle reinforced nanocomposites, and their revolutionary scope was also discussed.

The objective of this chapter is to review the recent progress on the tribological properties of natural fiber reinforced composites (NFRC). Specific emphasis is given to plant based fibers as they are abundantly available and share major portion of natural fibers than other natural fibers extracted from animal and mineral sources. The various factors affecting the friction and wear properties under dry and wet medium conditions of NFRC materials are discussed. An outline of the tribological test in NFRC materials are discussed with emphasis on test methods, NFRC materials and types of fibers. A general trend on the tribological properties with influencing parameters is represented in graphical format for readers to understand the interplay of various effects. The wear mechanism of NFRC and nanoparticle treated (such as nanocellulose and nanoclays) materials with respect to transfer film forming capabilities and measurement techniques were discussed. Commonly used theoretical analysis such as artificial neural networks (ANN) models for predicting frictional properties of NFRC were discussed. Overall, this chapter provides the reader a conscience and succinct information about friction and wear properties of NFRC materials that are studied in last two decades.

This work involves the study of the thermal, mechanical and physical properties of epoxy filled with nanoegg shell particles. Nanoegg shell particles of near uniform size and shape were prepared by high-speed ball milling technique. The influence of nanoegg shell particle concentration (1 to 5 wt.%) on epoxy curing rate, thermal stability, dynamic mechanical properties and the tensile, hardness, impact and water uptake properties was evaluated. The result showed improvement in most of these properties except for storage modulus in the rubbery phase. Microscopic examination revealed strong particle–matrix adhesion strength, with optimum improvement of all properties at 2 wt.% nanoegg shell filler concentration.

In the present study, we have synthesized and structurally characterized two biologically active derivatives of 1,2,4 triazoles, namely 3-(4-fluoro-3-phenoxyphenyl)-1-(piperidin-1-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione (TR) and 1-((3-(4-fluoro-3-phenoxyphenyl)-5-(methylthio)-1H-1,2,4-triazol-1-yl)methyl)piperidine (TR1) via single crystal X-ray diffraction. Both the structures show the presence of various intermolecular interactions in the crystalline solid such as C H…F, C H…S, C H…N, C H…O, C H … π, and π … π intermolecular interactions. The role of these interactions in molecular packing was analyzed, and the nature of these interactions was evaluated through computational procedures using PIXEL. Hirshfeld analysis further reveals that the contribution of H…F interactions was more prominent towards packing as compared to H…N/O intermolecular interactions.

The present research work deals with the development of a novel polymer composite for brake pad applications. The composite that was used consists of epoxy resin, carbon fibre and carbon nanotubes in varying weight percentage. The tribological performance of three different samples was tested using a pin-on-disc under dry contact condition. The results indicated that the sample filled with short carbon fibres (SCF), and multi-walled carbon nanotube (MWCNT) had superior performance. Reduction in wear rate was observed due to synergism between SCF and MWCNT as compared to SCF only. Scanning electron microscopy was subsequently performed on all samples. The micrographs show changes in the structural formation after the incorporation of SCFs and MWCNT. This increased composite structural strength and explains why SCF and MWCNT’s hybrid-filled composite material has better tribological properties.

Filler materials are commonly added to the polymer in the form of particles for various purposes, such as improving properties, to control processing and for economic benefits of the resulting polymer composite material. During the past five decades, much attention was given on synthetic fillers, such as CaCO3, TiO2, Al2O3, CNT and SiC. However, due to the concerns of environmental and depleting natural resources, researchers were started considering alternative fillers to the polymeric materials. They are moving towards green fillers and much advancement occurred in the past two decades. In this report, we focus on the review on the outline of various types of green nanofillers and their effect on the polymeric system. Green nanofillers are categorized based on their source, namely animal, plant and natural source. The latest progress on green nanofillers was also discussed. Their processing methods were discussed, and their effect on thermo-mechanical and physical properties was evaluated. The latest application of these green fillers was also studied.

The objective of this work is to study the tribological properties of natural fiber based composites using nanotechnology. The naturally available banana plant fibers were treated with nanoclay particles, and these treated fibers were then reinforced in an epoxy polymer to form composites. The friction and wear properties of nanoclay-treated banana fiber (NC-BF) reinforced composites were compared with untreated banana fiber (UT-BF) reinforced composites. Short NC-BF- and UT-BF-reinforced composites with fiber concentration ranging from 20 wt % to 60 wt % were prepared by the vacuum resin infusion processing method. The result indicates that the NC-BF-reinforced composites have shown improved friction and wear properties. Microscopy examination revealed that NC-BF-reinforced composites were able to form a transfer layer between the wear test specimen wear surface and counter face, resulting in improved wear properties. The nanoclay particles also induce increased hardness and friction to the composites and improve braking properties.

The objective of this work is to study the effect of nanoclay fillers on the biodegradation and barrier properties of corn starch polymer-based biofilm. Starch derived from corn plant source was used to prepare a biofilm by plasticization method. The barrier properties, namely, water absorption, moisture permeation, oxygen permeation and swelling of unfilled and nanoclay-filled corn starch biofilms were examined. The results indicate: ∼22% reduced water absorption, 40% reduced moisture uptake, 30% reduced oxygen permeation and 31% reduced swelling for 2–3 wt.% nanoclay-filled biofilm, when compared with unfilled biopolymer. The biodegradation result of unfilled and nanoclay-filled film series indicates that the nanoclay addition delays the biodegradation and is a function of nanoclay content in the film. The tensile, dynamic mechanical analysis and biodegradable studies were conducted on the biopolymers before and after water absorption, and the result shows that the nanoclay-filled biopolymer increased these properties when compared with unfilled biopolymer even after water absorption and is dependent on the nanocomposite structure and morphology as examined by X-ray diffraction and transmission electron microscopy analysis.

In this work, the tribological properties of a new class of hybrid composite material were examined. The hybrid composite consisting of glass fiber–reinforced epoxy polymer filled with nanoclay particles was prepared by vacuum-assisted resin infusion molding (VARIM). The effect of fiber content, fiber orientation, and nanoclay concentration on wear properties was examined. The results indicate that at higher fiber content (75 wt%), nanoclay addition in composites has less effect on the wear rate, whereas a significant positive effect was observed when nanoclay was filled in lower fiber content (25 and 50 wt%) composites. Microscopy examination reveals that nanoclay addition improves the wear properties of a matrix-rich phase at low fiber content with improved fiber matrix adhesion, whereas this effect was negligible in higher fiber content composites due to the reduced matrix concentration. The result also shows that the friction and wear of hybrids is a function of fiber orientation and epoxy–cla...

This study focuses on the thermoformability of biopolymer films derived from corn starch and filled with montmorillonite-based nanoclay fillers. Biopolymer films with nanoclay concentrations from 0 to 5 wt% were prepared by solution casting and followed by thermoforming. The result shows that nanoclay addition improves the formability (dimensional stability and plugging property) of thermoformed specimen and also depends on the nanocomposite structure and clay concentration. Improved product stability with optimized properties was observed at 2–3 wt% nanoclay concentration due to exfoliated structure and better nanoclay particle dispersion in the polymeric matrix. Thermogravimetric analysis and dynamic mechanical analysis show maximum of 27℃ increased decomposition temperature, 12% increased storage modulus and 4℃ increased Tg at 5 wt% nanoclay-filled biopolymer film. Tensile result shows 13% increased strength, two-fold increased modulus and 29% reduced elongation for 3 wt% nanoclay-filled biopolymer series.

The objective of this work is to infuse nanoclay particles into the banana fiber and study the morphological and structural characteristics. Nanoclays were infused into the fibers by shear induced force with the aid of alkaline (NaOH) chemical treatment. About 6 wt.% of nanoclays were infused into the banana fibers by this method. The short banana fiber reinforced epoxy composites were prepared by resin casting method in which the critical length ( lc) and critical volume fraction ( Vfc) of the fibers were determined. The nanoclay infused fibers were compared with untreated and alkaline treated fibers. The result suggests a positive effect on tensile, interfacial, and thermal properties of fibers due to nanoclay infusion. The tensile, shear, and dynamic mechanical analysis (DMA) of composites were studied, and the result shows superior improvement of these properties in nanoclay infused fiber composites.

The objective of this work was to find a possible engineering application for polypropylene (PP) by preparing fibers filled with nanoclay particles. Unfilled and nanoclay filled (0–5 wt%) PP fibers were continuously drawn and examined. The surface morphology and topographic studies of fibers were carried out using a scanning electron microscope (SEM). It was observed that unfilled PP fibers possess poor density distribution with the nonuniform diameter across the fiber length affecting structural integrity. However, PP fibers filled with ≥2 wt% nanoclay had shown improvement in structural integrity. The structure and morphology of fibers were examined by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis, and the result indicated good dispersion of nanolayers of clay in PP matrix with exfoliated nanocomposite structure up to 2 wt% nanoclay and above 2 wt% showing intercalated nanocomposite structure. Improved tensile, thermal and water barrier properties of nanoclay filled PP were also observed.

A comprehensive analysis of the crystal packing and the energetic features of a series of four biologically active molecules belonging to the family of substituted 4-(benzylideneamino)-3-(4-fluoro-3-phenoxyphenyl)-1H-1,2,4-triazole-5-(4H)-thione derivatives have been performed based on the molecular conformation and the supramolecular packing. This involves the formation of a short centrosymmetric R22(8) N–H···S supramolecular synthon in the solid state, including the presence of C–H···S, C–H···O, C–H···N, C–H···F, C–H···Cl, C–F···F–C, C–Cl···Cl–C, and C–H···π intermolecular interactions along with π–π stacking to evaluate the role of noncovalent interactions in the crystal. The presence of such synthons has a substantial contribution toward the interaction energy (−18 to −20 kcal/mol) as obtained from the PIXEL calculation, wherein the Coulombic and polarization contribution are more significant than the dispersion contribution. The geometrical characteristics of such synthons favor short distance, and t...

In the present study, we have prepared and structurally characterized a derivative of 1,2,4 triazoles, namely 3-(4-fluoro-3-phenoxyphenyl)-1-((4-methylpiperazin-1-yl)methyl)-1H-1,2,4-triazole-5-thiol (T-1) via single crystal X-ray diffraction. The crystal structure was observed to be stabilized by the presence of various intermolecular interactions in the crystalline solid such as O-H ⋯S, C-H ⋯F, C-H ⋯S, C-H ⋯N, C-H ⋯O, C-H ⋯π, lp⋯π and π⋯π intermolecular interactions. The interaction energy of these interactions was evaluated through PIXEL method with decomposition of the total energy into the coulombic, polarization, dispersion and repulsion contribution. The study of the nature of H-bonds with sulfur reveals that stabilization due to contribution from polarization plays a significant role. It is noteworthy that the presence of the solvent molecules in the crystal structure were observed to provide stabilization to an otherwise destabilized molecular pair (comprising of two molecules of 1,2,4 triazoles in the asymmetric unit).

This paper examines the influence of nanoclay on the structure, thermal and mechanical and gas barrier properties of a polyethylene terephthalate (PET)-based copolyester using a new modified formula. The copolyester considered in this work consists of partially replaced acid and diol monomers in main chain PET polymers, namely, polyethylene glycol (PEG) and isophthalic acid monomers, i.e., PET-IP. Nanoclays were filled from 0–3 wt% in PET-IP using the melt mixing method. The structural examination of composites tested by X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the distribution of nanolayers of clay particles in polymeric matrix. Up to 1 wt% nanoclay in PET-IP, an exfoliated structure resulted and above 1 wt% nanoclay an intercalated structure resulted. It was observed that 0.5 wt% nanoclay filled PET-IP resulted in improved nucleation characteristics and above 0.5 wt% nanoclay dramatically increased the gas transport (CO2, O2, N2 and water vapor), thermal and mechanical properties. The results also showed that the distribution of nanoclays affected the gas barrier properties of the polymer and can be controlled by processing parameters.

The objective of this work is to study the influence of nanoclay addition in PP sheet during infrared (IR) heating assisted thermoforming process. The effect of nanoclay on viscoelastic, friction and dimensional characteristics during sheet forming was examined. The result indicated that the nanoclay addition improves the sagging (sagging depth and sagging disintegration) and plugging (plug depth and friction) properties during sheet forming. The plugging properties of nanoclay filled PP sheet resulted in the improved physical characteristics (minimal change in thickness (Δt) and % dimensional elongation) when compared with unfilled PP sheet. The nanoclay filled formed PP sheet resulted in improved tensile and dynamic mechanical properties when compared with unfilled formed PP sheet.

This paper focuses on the resin flow characteristics of nanoclay filled glass fiber laminates processed by Vacuum Assisted Resin Infusion Molding (VARIM). Laminates with varying quantities of nanoclays (0–5 wt.%) were prepared and the effect of these nanoclays on the epoxy resin flow characteristics was studied. It was found that the flow rate of resin continuously decreased as nanoclay content continuously increased. The reduction in the flow rate was attributed to the rate of change of curing and the subsequent change in viscosity of the nanoclay filled resin. Analysis of infusion process by Darcy’s law show that the permeability of the fiber decreased in the nanoclay filled resin system. Nanoclay filled laminates show improved static and dynamic mechanical properties than that of unfilled resin composites.

We apologize to the authors and readers for these technical lapses made by the journal staff.

In the present study, we have synthesized and characterized two biologically active 1,2,4-triazole derivatives, a fluoro derivative, namely (E)-3-(4-fluoro-3-phenoxyphenyl)-4-((4-fluorobenzylidene)amino)-1-(morpholinomethyl)-1H-1,2,4-triazole-5(4H)-thione (TRZ-1), and a chloro derivative, namely (E)-4-((4-chlorobenzylidene)amino)-3-(4-fluoro-3-phenoxyphenyl)-1-(morpholinomethyl)-1H-1,2,4-triazole-5(4H)-thione (TRZ-2), via single crystal and powder X-ray diffraction. The chloro derivative crystallizes in an anhydrous form (TRZ-2A) and a solvated one (TRZ-2B) due to the presence of a toluene molecule in the crystal. This solvatomorphic behavior has been studied in detail using different thermal techniques, namely DSC and TGA, combined with hot stage microscopy (HSM). All of the three crystal structures show the presence of different intermolecular interactions of the type C–H⋯O, C–H⋯SC, C–H⋯π, C–H⋯X (X = –F, –Cl), π⋯π and lp⋯π interactions. The fingerprints for all these interactions were evaluated using Hirshfeld surfaces. The nature and energetics associated with these interactions were characterized using PIXEL and supported by ab initio quantum mechanical calculations using TURBOMOLE. In addition, the calculations performed on the evaluation of the electrostatic potential provide deeper insights into the nature of lp⋯π interactions.

The objective of this work is to study how the rheological factors of unfilled and nanoclay-filled HDPE–PP blend series influence the structure, morphology, and mixing characteristics. For this study, a series of HDPE–PP blends (0–100 wt % HDPE), with and without nanoclay, was prepared by using melt-mixing method. Nanoclay was varied from 0 to 5 wt % in all the blend and polymer series. The rheological properties were examined by melt viscosity, scanning electron microscopy, and theory of mixing. The result indicated that the viscosity of the blend increased as HDPE and nanoclay content increased, and also affected the structure and morphology of the resulting blend. The thermal properties were examined by using differential scanning calorimetry and suggest improved crystalline and melting characteristics of PP and PP-rich phase of blend. The structure of nanoclay-filled blend was examined by X-ray diffraction and transmission electron microscopy, confirming the formation of nanocomposite with improved tensile properties.

This paper presents the effect of moisture on fatigue properties of untreated and NaOH-clay-treated sisal fiber-reinforced epoxy and polypropylene (PP) composites. Sisal fibers were reinforced in e...

This article discusses the reuse of a thermoset-based epoxy polymer. In this method, cured epoxy polymer is ground to powder of particle size ranging from 1 to 30 μm. The ground epoxy is then filled in an epoxy polymer to form an epoxy–epoxy composite system using both room and high temperature processing. The amount of filler material was varied from 1 to 10 wt% in the epoxy matrix. Rheology and tensile properties test were then performed. The result shows that the room temperature-processed epoxy composites (above 5 wt% of powders) resulted in the formation of voids, agglomeration of particles, and reduced degree of cure leading to a decrease in tensile properties. These drawbacks (voids, agglomeration, and low degree of cure) were correspondingly absent in composites processed at high temperature. Results from this work suggest that the thermoset polymer can be reused effectively with minimal changes to the unfilled resin properties. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

In this study the chemical treatment of sisal fiber using the combined alkali (NaOH) and clay is discussed. The purpose of this fiber treatment is to improve the fiber–matrix compatibility, interface strength, mechanical, thermal and water barrier properties. The phase change due to chemical treatment of raw sisal fiber was examined by Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) methods. The result shows the presence of about 20 wt.% clays in NaOH–clay treated sisal fiber with 2.6× reduced water uptake and also with improved mechanical and thermal properties. Subsequently the treated and untreated fibers were reinforced in polypropylene (PP) matrix and the mechanical and thermal properties were examined. The result indicates that the fiber–matrix interface strength, adhesion, glass transition temperature and tensile properties of composites were improved in NaOH–clay treated fiber composites.

This paper discusses the improvement of water uptake property of NR-SBR type rubbers that are nanoclays filled. 1 wt.% to 3 wt.% nanoclays were filled in NR-SBR base rubber and the water uptake properties were examined. Results show that the nanoclay serves as viable filler in rubber polymer to protect them from high moisture absorption. The tensile, wear and dynamic mechanical analysis (DMA) properties were examined in these samples before and after placing them in a water medium. The results indicate that these properties were less affected in the nanoclay filled rubber than the base rubber.

The objective of this article is to study the combined effect of isophthalic acid (IPA) and polyethylene glycol (PEG-400) in PET polymer and film on thermal, mechanical, and gas transport properties. The purpose of developing this material is to reduce the melting point, improve mechanical, thermal, and gas barrier properties. The chosen raw materials, namely, IPA and PEG for copolyester synthesis will replace partially the acid and diol monomers of PET. The molar concentration of comonomers (IPA and PEG-400) were varied from 2 to 50% and the result shows that the gas barrier properties (namely O2, CO2, N2, and water vapor transmission rate), mechanical, and thermal properties were lesser than that of PET polymer. On improving the crystallinity of PET-isophthalate-PEG (PET-IP) copolymer, barrier properties are improved than that of PET polymer. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

This paper is about the study of catalytic effect of nanolayered montmorillonite- (MMT-) based organoclays (OCs) in epoxy polymer by directly monitoring their exothermic temperature versus time during curing. Untreated clays (UCs) of MMT were also filled in the epoxy polymer for comparative study. OCs and UCs were individually filled in epoxy polymer from 0 wt.% to 5 wt.%, and the curing characteristics were examined. The cure behavior of epoxy-OC composites changes as a function of OC concentration. Among the epoxy-OC systems, improved curing reaction was observed at 3 wt.% OC-filled epoxy composites. Addition of OC above 3 wt.% in epoxy reduces its catalytic effect due to presence of two types of cross-linking, namely, intergallery and extragallery cross-linking reactions. The curing behaviours of epoxy-UC composites were almost similar to those of pure epoxy polymer, and hence the results suggest that UC does not act as catalyst in epoxy polymer. The cured composite series was examined by studying their structure and morphology using X-ray diffraction (XRD), transmission electron microscopy (TEM) analysis, and the Fourier transform infrared (FTIR) spectroscopy.

This paper deals with the water mass uptake of nanoclay and sisal fibre reinforced polymer composites. Nanoclays at 1 wt.%, 3 wt.% and 5 wt.% were filled in sisal fibre reinforced epoxy polymer and placed in a water medium. The result shows a dramatic decrease in water mass uptake of nanoclay filled composites. The water transmission rate (WTR) for 5 wt.% nanoclay filled composites reduced by three times when compared to unfilled composites. Hence the role of nanoclay on reducing water uptake is studied and results are compared with microclay filled composites. Tensile, dynamic mechanical analysis (DMA) and wear studies were conducted for these composites before and after placing in the water medium. The properties decreased much for microclay filled and unfilled composites, however they improved significantly for nanoclay filled composites.