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This research aims to enhance natural rubber (NR) properties by incorporating spent coffee grounds (SCGs). Scanning electron microscope (SEM) reveals well‐dispersed SCG particles in the NR matrix without interaction. Shore A hardness notably increases by up to 49.90 (19% higher than unmodified), but tensile and tear strength decline with higher SCG levels. Optimal tear strength occurs at 10 phr of SCG due to uniform dispersion. The 300% modulus remains unchanged. The odor of composites (CO2 absorption) sees a 69.2% increase at 25 phr, while odor absorption efficiency peaks at 2%. Additionally, unmodified SCG affects scorch time (2.12%–23.40% increase from 1 to 20 phr) and cure time (3.12% to 76.82% improvement from 1 to 20 phr). These findings showcase improved hardness, enhanced CO2 absorption capacity, and effective odor control. Additionally, this study sheds light on the influence of SCG on processing times, contributing valuable insights for eco‐friendly applications. [ABSTRACT FROM AUTHOR]

The tensile behavior of a flexible epoxy resin reinforced with knitted reinforcements from various fiber materials was comprehensively studied in the wale and course direction. By measuring dry yarns, temperature‐treated yarns, dry knitted fabrics and flexible composites, the effect of the fiber material and the knitted fabric on the tensile properties was analyzed. The interlock knit structure strongly affected the deformation behavior of the flexible composites which differed significantly from the dry knitted fabrics. The deformation behavior of the flexible composites was monitored using digital image correlation which revealed the formation of cracks and high local strain differences in the course direction for all fiber materials. This was linked to fiber‐matrix debonding by scanning electron microscope observations. In the wale direction, the deformation of the knitted structure under tensile load led to plastic deformation of the matrix material. Overall, with yarns from recycled thermoplastic fibers, a higher maximum stress and strain at break was achieved compared to bio‐based fibers. However, irreversible damage occurred for all fiber materials at similar strain values. Highlights: Tensile tests on yarns, knitted fabrics and flexible composites.Investigation of the effect of fiber material on mechanical properties.High local strain differences in composites due to knitted structure.Fiber‐matrix debonding in course direction.Plastic deformation of the matrix material in the wale direction. [ABSTRACT FROM AUTHOR]

For commercial civil applications of laminated composite material, characterizations to forecast the interlaminar shear behavior and viscoelastic response across a wide temperature range are essential. In this study, the interlaminar shear strength (ILSS) of glass/epoxy (GE) composites dispersed with binary nanofillers nanosilica‐multilayer graphene (NS‐MLG) and nanosilica‐nanoclay (NS‐NC) was analyzed at an in‐situ testing temperature of 20, 70, and 110°C. Further, the viscoelastic property of the composites was studied using a dynamic mechanical thermal analyzer (DMTA) in the temperature range of 35–165°C. An increase in the ILSS value of around 9% and 10% was observed at room temperature for GE/MLG‐NS and GE/NC‐NS, respectively, compared to control GE composites. In contrast, the trend was seen to change at higher temperatures. There was a slight decrement in the storage modulus (E′) of GE/MLG‐NS and GE/NC‐NS composites in the glassy region compared to control GE composites. The mean Tg of the GE composite (control) was nearly 107.3°C when the E′ decline onset temperature was taken into account, but after the addition of MLG‐NS, it was 10.1°C below. The mean Tg of GE/NC‐NS was determined to be 106.3°C, and in the glass transition as well as rubbery regions, it was observed to compete with the E′ value of the control GE composites. Fractography was done using micrographs obtained from environmental scanning electron microscope (ESEM). Traces of polymeric material found at the fiber surface certified the improved interfacial adhesion between glass fiber and polymer in the matrix‐modified composite samples. [ABSTRACT FROM AUTHOR]

The present work is an attempt to study the effect of different surface treatments of flax fiber on the mechanical properties of the natural fiber reinforced natural rubber (NR) composites. In this study, flax fiber was chopped to 1, 1.25, and 1.5 cm in length and mixed with NR in two roll mill. The composite of 20%, 30%, 40%, and 50% fiber loading was prepared from each fiber length. Tensile analysis showed that a 1.25 cm fiber length composite of volume 40% has higher tensile strength compared to others. Hence, this optimized the fiber length and loading has opted for further study. Flax fiber was treated with NaOH and laccase and reinforced into an NR matrix. Properties like tensile strength, hardness, relative density, water diffusion, scanning electron microscope (SEM) and Fourier‐transform infrared spectroscopy (FTIR) for surface treated and untreated natural fiber‐reinforced NR composites have been investigated and compared. The reduction in the hydrophilic characteristics of the NaOH and laccase treated fiber was evident from FTIR analysis and increase in the crystallinity index of the fiber depicted by X‐ray diffraction (XRD) results. SEM analysis showed the enhanced interfacial interaction of treated flax fiber NR composite compared to untreated composite due to the removal of non‐cellulosic contents in fiber and an increase in the surface roughness after treatments. Further, an increase of 9% and 27.4% in tensile and tear strength was found in NaOH treated flax fiber reinforced NR composite. [ABSTRACT FROM AUTHOR]

In this work, a chemical precipitation procedure for decorating graphene oxide (GO) with Fe2O3 nanoparticles was described. Iron(III) chloride (FeCl3) was employed to generate the nano‐Fe2O3 particles onto the GO surface in the presence of sodium hydroxide. The Fe2O3@GO hybrid was characterized by various techniques of X‐ray diffraction, Fourier transform infrared spectroscopy, Field‐emission scanning electron microscope, Raman spectra, and Atomic‐force microscopy. The epoxy (EP)‐matrix nanocomposites containing various Fe2O3@GO loadings (0–0.8 wt% at a step of 0.2) were prepared by mechanical stirring and ultrasonic treatment. Mechanical properties of these composites were explored using the three‐point bending and dry‐sliding wear tests. The results revealed that the best flexural and wear behaviors were related to the specimens containing 0.2 and 0.6 wt% Fe2O3@GO hybrid, respectively. The incorporation of 0.2 wt% Fe2O3@GO was found to increase the flexural strength and modulus by 24% and 29%, respectively. Additionally, mass reduction and friction coefficient were decreased by 97% and 66% respectively, due to the addition of 0.6 wt% Fe2O3@GO. Most importantly, in comparison with the untreated‐GO/EP composite, the specimens containing Fe2O3@GO have attained higher improvements in flexural and wear properties. Finally, morphology of the fractured and worn surfaces was also evaluated. [ABSTRACT FROM AUTHOR]

The current research article assesses the feasibility of recycled CFRP (Carbon‐Fiber‐ Reinforced‐Polymer) fibers in high‐strength concrete. Different dosages of recycled CFRP fibers (0.2%, 0.4%, 0.6%, 0.8%, and 1%) as well as different aspect ratios of CFRP fibers with 10 and 20 mm fiber lengths is assessed for hardened state characteristics of reinforced high‐strength concrete. Furthermore, ultrasonic pulse velocity test, compression test, flexure test, and impact resistance test are performed to understand the hardened properties of specimens. The chemical composition of various elements present in the various kinds of concrete samples is qualitatively and quantitatively found with the help of energy‐dispersive X‐ray spectroscopy (EDX) equipment. To understand the surface morphology of carbon fibers incorporated in concrete samples, Scanning electron microscope (SEM) photographs are obtained to examine the prepared samples thoroughly. Linear regression analysis, an analytical analysis technique, is incorporated to linearly correlate the different hardened mechanical characteristics of specimens taking into account varying lengths and different dosages of recycled CFRP fiber. The findings reveal that increasing the CFRP fiber dosage and the aspect ratio of recycled CFRP fiber improves the reinforced mix composition's mechanical characteristics. [ABSTRACT FROM AUTHOR]

In this study, S‐doped graphene (SG) powders were produced in one‐step green and environmental‐friendly, quick, and cheap route of Yucel's method. Different sulfur functional groups were formed on graphene surfaces by changing the anodic potential range and were first used to prepare SG/polylactide (PLA) nanocomposites. The influence of applied potential on the structural properties of SG powders was explored through cyclic voltammetry (CV), X‐ray photoelectron spectroscopy (XPS), X‐ray diffractometry (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and BET surface area analysis. S‐doped graphenes were subsequently melt mixed with polylactide at low contents of 0.1 and 0.5 wt% using a twin‐screw extruder. The interaction of SGs functional groups with PLA and its effect on the nanocomposites' final morphological, thermomechanical, and tensile properties was then studied. It was revealed that the tensile strength and modulus of the nanocomposites were noticeably increased with the addition of such low SGs contents. The applied potential and hence the structural properties of SGs differently influenced the final tensile properties of the nanocomposites. A maximum enhancement of around 100% in tensile strength was observed using only 0.1 wt% SG produced at the potential range of −1.5 and 2.3 V. [ABSTRACT FROM AUTHOR]

The mechanical and thermal characterization of Moringa oleifera fiber and red mud (RM) reinforced chitosan (CS) based hybrid composite is the subject of this research. By varying the percentages of M. oleifera fiber and RM in the hand lay‐up process, seven types of composite samples were developed. Tensile, flexural, compression, and impact testing were performed in accordance with ASTM standards. A scanning electron microscope was used to examine the cracked surfaces of the tested specimens. Hybridization with M. oleifera fiber and RM increased the characteristics of CS composites, according to the findings. Increase in the percentage composition of RM resulted in better mechanical characteristics of fiber‐reinforced composites. C6 type composite revealed maximum tensile strength of 65.59 MPa and impact strength of 24.86 kJ/m2. It also had better dynamic mechanical qualities, while C6 composite had the best static and dynamic mechanical properties. Overall it may be concluded that composites can be utilized in light weight structural applications. [ABSTRACT FROM AUTHOR]

Delamination is always considered as a threat to the resin matrix composite laminates due to the nonvisibility from the outside. Much effort on the interleaving toughening has been made to improve the interlaminar fracture toughness. The synergistic toughening effect of thermoplastic resin and carbon nanotubes (CNTs) has been the topic in the interleaving toughening. In this study, the influence of the hybrid structure between thermoplastic polyetherketone‐cardo (PEK‐C) and CNTs on the toughening efficiency was investigated. The mode II interlaminar fracture toughness was tested and the fracture surface was examined by scanning electron microscope. The results showed that the interlaminar structure was closely related with the interlayer structure and the synergistic toughening effect depended greatly on the hybrid structure. [ABSTRACT FROM AUTHOR]

This study compares the mechanical properties of rice husk (RH) and rice husk ash (RHA) filled polypropylene (PP) composites and the effects of ethylene‐acrylic‐ester‐maleic anhydride (E‐AE‐MA) and PP‐g‐maleic anhydride (MAPP) as compatibilizer. In this study, PP/RH and PP/RHA composites were blended at the ratios of 85/15 wt% and compatibilizers at four parts per hundred each, via melt extrusion in a twin‐screw extruder prior to injection molding. Mechanical tests were tensile, flexural and impact tests. A morphological study was conducted by scanning electron microscope (SEM). Results show that PP/RHA composite exhibited a 4% significant increase in tensile strength compared to PP/RH composite (р ˂ 0.05) while, PP‐RH composite increased significantly by 5 and 3% in flexural and impact strength compared to PP‐RHA composite (р ˂ 0.05). MAPP increased significantly the flexural strength of PP‐RH and PP‐RHA composites by 23 and 21% (р ˂ 0.05) compared to E‐AE‐MA. PP‐RHA‐MAPP composite increased significantly the impact strength by 18% compared to PP/RHA/E‐AE‐MA composite (р ˂ 0.05). There was no significant difference in impact strength between PP/RH/MAPP and PP/RH/E‐AE‐MA composites (р ≥ 0.05). Overall results indicate that RH imparts better reinforcing effect in PP composite than RHA, while MAPP is a better compatibilizer. SEM study indicates that both compatibilizers improved the filler‐matrix interfacial adhesion. [ABSTRACT FROM AUTHOR]

Kota stone dust (KSD) and fly ash (FA) are the wastes generated from the construction industry and thermal power plant, respectively. In the present work, a novel hybrid composite is developed to utilize KSD and FA as reinforcing phases in the epoxy matrix. The hand lay‐up method is adopted for the fabrication of 12 sets of samples. Four sets are prepared with single filler KSD and eight samples are prepared with a hybrid combination of KSD and FA. The prepared samples are undergone physical and mechanical tests. To understand the compatibility between filler‐matrix and visualize the dispersion of fillers in epoxy, micrographs are taken using the scanning electron microscope. The density and void contents of the material increases with an increase in filler content. The maximum water absorption measured is 0.96% for the combination of epoxy with 40 wt% KSD and 10 wt% FA. From mechanical testing, maximum tensile strength and flexural strength obtained is 34.4 MPa and 65.4 MPa, respectively, for a combination of epoxy with 20 wt% KSD and 5 wt% FA. Compressive strength and hardness increase with either of the content of the filler and reaches 116.28 MPa and 104 Shore D number, respectively, with 40 wt% KSD and 10 wt% FA. From experimentation, it was found that mechanical properties of the hybrid composites are better as compared to that of single filler composites though physical properties are slightly compromised by hybridization of fillers. [ABSTRACT FROM AUTHOR]

Nanoparticles have been widely used in the improvement of the mechanical and thermal properties of the epoxy matrix. In this study, the room temperature curing agent composed of acrylic acid and 2,4,6‐trimethyl‐m‐phenylenediamine was mixed with different concentrations of CeO2 nanoparticles into the epoxy resin (E51) to obtain a nanocomposite that can be rapidly molded and cured. Fourier transform infrared spectroscopy and differential scanning calorimetry were used to study the curing behavior of nanocomposites and E51 with the synthesized hardener. Through tensile, flexural, and impact tests, the influence of the nanoparticles content on the mechanical and thermal properties of the prepared composites was discussed. The results showed that the curing process was completed in 4 h. An increase of 78.4% in tensile strength, 81.7% in flexural strength, and 122.0% in elongation were obtained for the cured nanocomposite having 5 wt% CeO2 loading compared to the neat resin. Thermogravimetric analysis result showed that the thermal stability increased with increasing of CeO2 nanofillers content. Finally, the scanning electron microscope revealed the fracture surface morphology of the composites. [ABSTRACT FROM AUTHOR]

A 3D architecture carbon fiber preform, specifically fine‐woven cloth and punctured felt preform, is used to manufacture a novel advanced Cf/C‐SiC‐ZrC composite. The composite matrix is produced by chemical vapor infiltration (CVI) plus precursor infiltration and pyrolysis (PIP) process and finalized by using a chemical vapor deposition (CVD) of SiC coating to make the final density of the material reach 1.95 g/cm3. The organic precursors of SiC and ZrC have a weight ratio of 4:1 in a xylene solute. The composite mechanical properties, such as tensile, compression, bending, shear, and Z‐direction load bearing, are introduced under analysis to find possible applications for the composite. What is more, scanning electron microscope (SEM) images are employed to illustrate the failure behavior of the ceramic composite. The results showed that the punctured filament tows will be beneficial, not only for the composite to withstand compression force up to 308.6 MPa and shear strength to 18.14 MPa but also for the alternatively stacked weave piles and short fiber layers to support the punctured bundles, as well as to hold the composite structure under mechanical forces from different orientations, which is believed to reinforce the ceramic matrix for some high pressure and severe ablation applications. [ABSTRACT FROM AUTHOR]

Polysulfone (PSU) is a widely used polymer in water purification membranes. However, its hydrophobicity hinders its practical application. Herein, the wettability of PSU has been improved by producing a coelectrospun fibrous composite membrane using a hydrophilic component, chitosan‐polyvinyl alcohol (CS‐PVA). First, different proportions of PVA and CS solutions were mixed and electrospun to prepare CS‐PVA blend fibers. Scanning electron microscope (SEM) observations revealed that CS‐PVA blend fibers with maximum CS content can be obtained in 30:70 CS:PVA weight ratio. The optimum CS‐PVA solution was subsequently used alongside PSU solution and were fed into two distinct syringes, which were then electrospun simultaneously at a constant voltage and distance of 15 kV and 15 cm, respectively. Different composite compositions of PSU/CS‐PVA were achieved using different feeding rates for each solution. Based on SEM images, the prepared composite fibers were beadless. The ultimate strength of the composite mats decreased by increasing the amount of CS‐PVA due to the significant difference in the fiber diameter of each component and the resulting stress concentration. However, the thermal stability of composite membranes remained almost the same as pure PSU fibers. Moreover, samples with higher CS‐PVA content showed better wettability and higher water flux. [ABSTRACT FROM AUTHOR]

In this study, cryptocrystalline graphite (CG) was investigated as a novel functional filler for acrylonitrile‐butadiene rubber (NBR)/carbon black (CB) composites. NBR/CB/CG composites are characterized by X‐ray diffraction (XRD), scanning electron microscope (SEM) as well as differential scanning calorimetry (DSC). The results showed that NBR/CB/CG‐10 increased by 18.2%, 11.0%, and 10.0% in tensile strength, 300% tensile modulus and tear strength, respectively compared with NBR/CB. Uniform filler dispersion and stronger interfacial interaction contributed to enhancing the mechanical property of NBR/CB/CG composites. It was revealed that the small particle size, rough surface, and defective structure of CG facilitated its exfoliation and intercalation. In addition, the tribological performance of NBR/CB/CG composites was tested on a ring‐on‐block wear tester under dry sliding conditions. The friction coefficient and specific wear rate of NBR/CB/CG‐5 reduced by 50.3% and 51.4%, respectively through the formation of fine lubrication and transfer films. CG enhanced the thermal stability, mechanical, and tribological performance of NBR composites simultaneously and the results of this work proved that CG would be a cost‐effective and resource‐available functional filler especially suitable for rubber seal application. [ABSTRACT FROM AUTHOR]

Oleylamine (OA) modified silica (SiO2‐g‐OA) was prepared using γ‐(2,3‐epoxypropoxy) propytrimethoxysilane (KH560) and OA, silica/natural rubber (NR) and SiO2‐g‐OA/NR composites were prepared by mechanical blending in an internal mixer, and SiO2‐g‐OA was characterized by Fourier transform infrared spectroscopy, thermal gravimetric analyzer, and contact angle analyzer. The mechanical properties, abrasion resistance, curing characteristics, Payne effect, and morphology of silica/NR and SiO2‐g‐OA /NR composites were investigated using universal testing machine, Akron abrasion tester, rubber processing analyzer, and scanning electron microscope, respectively. The results showed that SiO2‐g‐OA became more hydrophobic and had better compatibility with NR. Moreover, SiO2‐g‐OA/NR had weaker Payne effect, better vulcanization performance, and more excellent mechanical properties. As the content of filler was more than 30 phr, SiO2‐g‐OA/NR had lower rolling resistance and higher wet skid resistance. Compared with silica modified by other coupling agents, SiO2‐g‐OA had the best reinforcement effect on NR. [ABSTRACT FROM AUTHOR]

ZnS‐reinforced ZnS/ZnSe composites are prepared by chemical vapor deposition. Scanning electron microscope, transmittance, and bending strength are used to characterize the samples. The schematic diagram of the transmittance model of the double‐layer composite window is used to calculate the theoretical transmittance, and the measured value of the transmittance of ZnS/ZnSe composite material is in good agreement with the calculated value. The effects of interface layer on the optical and mechanical properties of materials are studied in detail. It is found that the interface can affect the transmittance of the composites, but it still maintains a high transmittance, and the influence of interface layer on the transmittance of visible band is more serious than that of infrared band. Moreover, the mechanical properties of the new composite material are significantly improved (35%). [ABSTRACT FROM AUTHOR]

A silicon oxide (SiO2) nanoparticles‐decorated short carbon fiber (SCF) hybrid (SCF‐SiO2) was designed to improve the weak interfacial bonding between fibers and matrix. Nano‐SiO2 was grafted onto carbon fibers by introducing amino group and epoxy group on the surface of carbon fibers and SiO2, respectively. The chemical composition of SCF‐SiO2 was analyzed by Fourier transform infrared spectrometer and energy‐dispersive spectrometry, the microstructure of SCF‐SiO2 were investigated by scanning electron microscope, and then the hybrid filler was introduced into Poly(ether ether ketone) (PEEK). Due to the strong interfacial interaction between filler and matrix, the mechanical and tribological properties of SCF‐SiO2/PEEK composites were significantly better than SCF/PEEK composites. In order to further improve the tribological properties of the composites, micrometer‐sized cenosphere (CS) particles were introduced into the aforementioned system to prepare multicomponent composites. The test results of friction and wear indicate that the CS/SCF‐SiO2/PEEK composites have the optimal tribological properties. Compared with pure PEEK, the friction coefficient of CS/SCF‐SiO2/PEEK composites under 200 N load decreases by 56.4% and the specific wear rate decreases by 87.4%. Meanwhile, the thermal decomposition temperature of CS/SCF‐SiO2/PEEK composites is increased by 40 °C compared to pure PEEK. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48749. [ABSTRACT FROM AUTHOR]

Bamboo fiber (BF)‐reinforced starch/polypropylene (PP) composites were prepared by extrusion and injection molding methods. The mechanical and thermal properties and water absorption were evaluated by different methods. Moreover, composite samples were subjected to biodegradation through soil burial test and microbes medium degradation. Different stages of biodegradation were investigated by weight loss, attenuated total reflection Fourier transformed infrared spectroscopy, differential scanning calorimeter, and scanning electron microscope. It was found that contents of BF and starch resin had a significant influence on the properties of the composites. With more content of BF, the composite exhibited a better flexural property and biodegradation. A distinct decrease of weight loss and mechanical properties indicated the degradation caused by the microbes. After biodegradation, thermal stability of the composites decreased while the crystallinity of PP increased. The results prove that the composites more easily tend to be degraded and assimilated by microbes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48694. [ABSTRACT FROM AUTHOR]

In the present study, the reinforcing effect of aluminum silicon carbide (Al‐SiC) nanoparticles and chemically treated nanocellulose fiber on thermomechanical and corrosion characteristics of polymer nanocomposites have been investigated. The experimental design was selected as per response surface methodology (RSM) to optimize the effect of Al‐SiC (1.59 to 18.41 wt%), nanocellulose fiber concentration (1.59 to 18.41 wt%) and sonication time (39.55 to 140.45 minutes). From the analysis of variance (ANOVA) results, it was found that the Al‐SiC, nanocellulose fiber concentration and sonication time played a significant role in the mechanical properties. In order to simultaneously maximize the flexural strength, the optimal values of nanocellulose fiber, Al‐SiC nanoparticles, and sonication time was found to be 5 wt%, 5 wt%, and 120 minutes, respectively. From the normal distribution plot, it is found that there is a good agreement between experimental results and developed RSM model. Addition of Al‐SiC (5 wt%) and nanocellulose fiber (5 wt%) in epoxy polymer improved the physical, mechanical, thermal and corrosion resistance properties. The scanning electron microscope analysis on Al‐SiC and nanocellulose fiber reinforced epoxy nanocomposites revealed uniform dispersion of nanocellulose fiber and Al‐SiC in the polymer matrix, which caused for the improved mechanical, and corrosion resistance characteristics. [ABSTRACT FROM AUTHOR]

ABSTRACT Natural rubber-epoxidized natural rubber-silica composites were prepared by the wet masterbatch technique and the traditional dry mixing method. Performances of the composites based on different preparation methods were investigated with a moving die rheometer, an electronic universal testing machine, a dynamic mechanical analyzer, a nuclear magnetic resonance crosslink density analyzer, a rubber processing analyzer (RPA), a scanning electron microscope (SEM), and a transmission electron microscope (TEM). The RPA, SEM, and TEM analyses indicated that silica has better dispersion, lower filler-filler interaction, and better filler-rubber interaction in compounds based on the wet masterbatch technique, leading to improvements in mechanical strength and the dynamic mechanical and compression properties of the composites. It also indicates that composites prepared by the wet masterbatch technique have shorter scorch time, faster curing velocity, and higher crosslink density. The composites prepared by the wet materbatch technique also have lower rolling resistance, which is an important property for their use as a green material for the tire industry. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43571. [ABSTRACT FROM AUTHOR]

ABSTRACT To investigate the mechanical properties and fracture mechanisms of hydroxyl-terminated polybutadiene (HTPB) propellant at low temperature and high strain rate, uniaxial tensile tests were conducted over the range of temperatures 233 to 298 K and strain rates 0.4 to 14.14 s−1 using an INSTRON testing machine, and scanning electron microscope (SEM) was employed to observe the tensile fracture surfaces. The experimental results indicate that the deformation properties of HTPB propellant are remarkably influenced by temperature and strain rate. The characteristics of stress-strain curves at low temperatures are different from that at room temperature, and the effects of temperature and strain rate on the mechanical properties are closely related to the changes of properties and the fracture mechanisms of HTPB propellant. The dominating fracture mechanism depends much on the temperature and changes from the dewetting and matrix tearing at room temperature to the particle brittle fracture at low temperature, and the effect of strain rate only alters the mechanism in a quantitative manner. Finally, a nonlinear viscoelastic constitutive model incorporating the damage evolution and the effects of temperature and strain rate was developed to describe the stress responses of this propellant under the test conditions. During this process, the Schapery-type constitutive theories were applied and one damage variable was considered to establish the damage evolution function. The overlap between experimental results and predicted results are generally good, which confirms that the developed constitutive model is valid, however, further researches should be done due to some drawbacks in describing the deformation behaviors at very large strain. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42104. [ABSTRACT FROM AUTHOR]

ABSTRACT New synthetic Ni-talc was used as filler in the synthesis of polyurethane (PU) nanocomposites by in situ polymerization and to emphasize the contribution of the new material compared with natural talc. Good dispersion of Ni-talc was supported by homogeneous green coloration observed in the polymer matrix. X-ray diffraction (XRD) analyses indicate the intercalation of polymeric matrix into the filler layers by the increase in d001-spacing value of the Ni-talc for the nanocomposites when compared to the pristine filler. The nanocomposites obtained with synthetic talc showed an improvement in the crystallization temperature and in thermal stability when compared to pure PU and the composite obtained with natural talc. The young modulus of PU/talc materials containing both Ni-talc and natural talc were slight higher than pure PU. As shown by scanning electron microscope (SEM), Ni-talc fillers were well dispersed into the polymeric matrix probably due to the good compatibility of both phases filler/polymer mainly achieved by the filler OH interaction with the urethane group of the polymeric chain. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41854. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, copper (Cu) crystallites were successfully prepared via low temperature molten salt method, and the possible formation mechanisms were proposed. The conductive fillers of multiwalled carbon nanotubes (MWCNTs) and as-prepared Cu particles were designed and introduced into acrylonitrile-butadiene-styrene (ABS) blend to prepare different conductive composites. The dispersion states of conductive fillers and the morphologies of the composites were characterized using a field emission scanning electron microscope. The electrical resistivity of different composites was measured. The results showed that Cu and MWCNTs exhibited a synergistic effect in decreasing the electrical resistivity of the Cu/MWCNTs/ABS composites, because Cu that could locate between MWCNTs chain segments provides a better charge transport in the conductive pathways. Compared with pure ABS, the tensile strength, elastic modulus and thermal stability of the Cu/MWCNTs/ABS composites were significantly improved with the incorporation of Cu and MWCNTs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41738. [ABSTRACT FROM AUTHOR]

ABSTRACT Rice husk flour (RHF) biocomposites based on uncompatibilized and compatibilized recycled high density polyethylene/recycled polyethylene terephthalate (rHDPE/rPET) with ethylene-glycidyl methacrylate (E-GMA) copolymer were prepared through a two-step extrusion and hot pressing with fiber loadings of 40, 60, and 80 wt %. Results showed that tensile and flexural properties increased. However, the elongation to break and impact strength decreased as the RHF loading increased. Compatibilizing polymer blend matrices can further enhance the mechanical properties. Water absorption (WA) test were examined in distilled and seawater. It is interesting to note that for composites made from uncompatibilized matrix, the calculated D and KSR were lower in seawater, but for the compatibilized matrix composites, the D and KSR obtained were generally lower in distilled water. However, compatibilization of rHDPE/rPET has been markedly reduced the WA and thickness swelling. Scanning electron microscope analysis of the compatibilized matrix composites confirmed the improved interfacial bonding of matrix-matrix and filler-matrix phases. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41494. [ABSTRACT FROM AUTHOR]

The influences of size and content of silicon dioxide (SiO2) nanoparticles on the morphological, optical, toughness, and thermal properties of polycarbonate (PC) were investigated. The PC nanocomposites were prepared using a twin‐screw extruder followed by injection molding. The scanning electron microscope (SEM) micrographs displayed an adequate level of nano‐SiO2 particle distribution within the PC matrix but still revealed some agglomerated particles. Upon increasing the content of nanoparticles, slightly larger agglomerates formed. These agglomerated particles caused a reduction in material transparency due to light loss via reflection and scattering. However, the incorporation of nano‐SiO2 into the PC matrix greatly improved toughness properties and slightly increased glass‐transition temperature (Tg), in conjunction with filler content (up to 4 vol %). This was particularly in the case with the smaller sized nano‐SiO2, which not only significantly improved toughness but also enhanced optical properties of the PC nanocomposites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47634. [ABSTRACT FROM AUTHOR]

To improve fire retardant behavior of bio‐epoxy resin, composites were prepared with three fire retardants (FRs); ammonium polyphosphate, aluminum trihydrate, and magnesium hydroxide. Fractured surfaces of prepared composites were observed with the scanning electron microscope (SEM). Tensile strength and Charpy toughness were evaluated and analyzed statistically using analysis of variance (ANOVA). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to determine the thermal stability. SEM analysis results revealed fractured surfaces were altered with addition of FRs. Adding FRs can be regarded as a decrease in tensile strength and toughness complemented by improved stiffness. ANOVA analysis showed FR/bio‐resin composites have a statistically significant loss in tensile strength, stiffness, elongation, and Charpy toughness. The DSC results showed the glass transition temperature was not affected significantly by adding FRs and ranged from 66 to 69 °C. TGA showed the initial, midway, and maximum decomposition temperatures for composites and their ability to form improved ash yields compared to pure resin. Aluminum trihydrate and Mg(OH)2 had higher T50 suggesting an increase in thermal stability compared to pure bio‐epoxy. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47398. [ABSTRACT FROM AUTHOR]