Chemically functionalized SiO2 to improve mechanical properties of oil-impregnated monomer casting nylon

ABSTRACT: Toluene-2,4-diisocyanate and dodecanol were used to chemically functionalize nanosilica (TDID-SiO₂). Composites of TDID-SiO₂ and oil-impregnated monomer casting nylon (OMC nylon) were prepared by an in situ anionic ring-opening polymerization. The dispersion of the TDID-SiO₂ in oil was studied along with the mechanical and friction properties of the composites. The results show that the dispersion of the TDID-SiO₂ in oil was significantly enhanced. Specifically, some TDID-SiO₂ was wrapped in oil droplets, and the size of the oil droplets increased from 2.3 to 3.3 μm for 0–0.125 wt % of the TDID-SiO₂ nanoparticles, which was confirmed by scanning electron microscopy. The composites exhibited excellent mechanical properties when 0.10 wt % TDID-SiO₂ was integrated into OMC nylon. The tensile strength, elastic modulus, notched impact strength, flexural strength, and flexural modulus increased by 6.9%, 7.1%, 33.2%, 15%, and 77.5%, respectively, compared to OMC nylon without TDID-SiO₂ nanoparticles. The friction coefficient was effectively controlled and the abrasion quantity was reduced. Thermogravimetric analysis showed that the thermal decomposition temperature was also improved. The improved mechanical and frictional properties of TDID-SiO₂/OMC nylon composite will enhance its application in wear-resistant products in heavy industry. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46994.     

Effect of modified Mg2B2O5w on mechanical and friction properties of oil-containing monomer casting nylon

The Mg₂B₂O₅w modified by toluene-2, 4-diisocyanate (TDI) and fatty amine (n-dodecylamine(D) or n-octadecylamine (O)) was used in oil-containing monomer casting (OMC) nylon, and the effect of modified Mg₂B₂O₅w on mechanical and friction properties of OMC nylon composites was investigated. The significant improvement of the mechanical and friction properties of composites was observed. The addition of 0.15 wt% TDI-D-Mg₂B₂O₅w or TDI-O-Mg₂B₂O₅w resulted in 21 and 20% growth in the tensile strength, 53 and 52% increase in the flexural strength, respectively. Additionally, nearly 60 and 58% reduction in the friction coefficient, about 84 and 80% decrease in the abrasion quantity. Furthermore, the worn surface of composites exhibited smooth, which confirmed the antiwear effect of Mg₂B₂O₅w. The improvement was attributed to the interfacial adhesion between whiskers and matrix by hydrogen bonds. This work provided a facile approach to the design of wear-resistant polymer composites that hold significant potential in construction machinery industry. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48856.     

Anionic nylon 6/TiO2 composite materials: Effects of TiO2 filler on the thermal and mechanical behavior of the composites

The nylon 6‐based composite materials containing untreated and surface‐treated TiO₂ particles with 3‐aminopropyltriethoxysilane (APTEOS), as coupling agent were prepared by in situ anionic polymerization of ε‐caprolactam in the presence TiO₂ as a filler using the rotational molding technique. The thermal behavior and mechanical properties of the neat nylon 6 and its composites were investigated using various techniques such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), a tensile and flexural test and impact strength. Experimental results revealed that both untreated and surface‐modified TiO₂ had distinct influence on the melting temperature (T_m), crystallization temperature (T_c), and degree of crystallinity (α_DSC), thermal stability, storage modulus (E′), and loss factor (tan δ), and mechanical properties of nylon 6 matrix. Dynamical mechanical analysis indicated that addition of TiO₂ particles into nylon 6 matrix increased both the storage modulus and the glass transition temperature. The corresponding values of nylon 6 composites with modified filler were higher than that of nylon 6 composite with untreated TiO₂ particles. Tensile and flexural characteristics of the nylon 6 composites were found to increase while the elongation at break and impact strength with increase in TiO₂ concentration relative to neat nylon 6. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Microstructural characterization of short glass fiber and PAN based carbon fiber reinforced nylon 6 polymer composites

Microstructural characterization of nylon 6/short glass fiber (SGF) and nylon 6/polyacrolonitrile based carbon fibers (PAN‐CFs) of 10 to 40 wt% has been performed by positron lifetime technique (PLT). The positron lifetime parameters viz., o‐Ps lifetime (τ₃), o‐Ps intensity (I₃), and fractional free volume (F_v) of nylon 6/SGF and nylon 6/PAN‐CF composites are correlated with the mechanical properties viz., tensile strength and Young's modulus. The F_v shows negative deviation with the reinforcement of 10 to 40 wt% of PAN‐CF and show positive deviation in nylon 6/SGF from the linear additivity relation. The negative deviation in nylon 6/PAN‐CF composite suggests the induced molecular packing due to the chemical interaction between the polymeric chains of nylon 6 and PAN‐CF. The positive deviation in nylon 6/SGF composite indicates the formation of interface between the polymeric chains of nylon 6 and SGF. The increased crystallinity of nylon 6/SGF and nylon 6/PAN‐CF composites shows the improved mechanical properties of the composites. The hydrodynamic interaction parameter (h), which shows more negative values in nylon 6/SGF than nylon 6/PAN‐CF composites. However, the extent of chemical interaction in nylon 6/SGF is less compare to nylon 6/PAN‐CF composites. This is evident from Fourier transform infrared spectrometry studies. POLYM. ENG. SCI., 58:1428–1437, 2018. © 2017 Society of Plastics Engineers     

Synthesis and properties of fluorinated graphene oxide bisphenol a epoxy nanocomposites

This study thoroughly studied the implements of fluorosilane modified graphene oxide (GO) on the mechanical, thermal, and water absorption properties of the epoxy composites built up by specific content of modified GO. Fluorosilane graphene oxide (GOSiF) was analyzed using Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, X‐ray photoelectron spectroscopy, and X‐ray diffractometer. The epoxy composites tensile and bending modulus were increased by 11.46% and 62.25% with 0.1 and 0.5 wt% GOSiF loading, respectively. The good interfacial interaction was observed between epoxy matrix and GOSiF nanosheets under scanning electron microscopy. The thermal stability increases with GOSiF loading. Epoxy composite with 0.3 wt% GOSiF shows 5 °C increases in the T_10%. The residual weight raised by 58.67% with 0.3 wt% GOSiF content. The water absorption study revealed small water uptake was obtained for all GOSiF composites. With 0.3 wt% loading of GOSiF, the maximum water content drops from 4.97% for neat epoxy to 1.98%. POLYM. ENG. SCI., 59:1250–1257 2019. © 2019 Society of Plastics Engineers     

Preparation of X‐ray developable LDPE/SA‐BaSO4 composites and their thermal and mechanical properties

Low‐density polyethylene (LDPE)/barium sulfate (BaSO₄) composites with different contents of BaSO₄ nanoparticles after modification by stearic acid (SA) were prepared. Characterizations of morphology, thermal, and mechanical properties of the LDPE/SA‐BaSO₄ composites were systematically performed by scanning electron microscope, thermal gravimetric analysis, tensile and flexural tests. Specially, the X‐ray radiographic and developable properties were examined by the X‐ray fluoroscopy test and the ageing resistant properties were analyzed by the simplified protocol of accelerated aging. It was found that the Young's modulus and tensile strength of the composites were increased by 24.6 and 11.0% while flexural modulus and flexural strength were increased by 10.8 and 14.0%, respectively, together with the elongation at break of 455.1% ± 26.3% which was 74.4% of LDPE when the SA‐BaSO₄ content reached 25 wt%. By contrast, when accelerated ageing for 5 years, the retention ratios of Young's modulus, tensile strength and elongation remained at 89.3, 69.5, and 69.6%, respectively. In addition, X‐ray radiographic and developable properties of the composites were also improved by the addition of SA‐BaSO₄, making it possible to achieve some applications in medical devices such as intrauterine devices and body brackets which could be easily implanted into human bodies and enable accurate external monitoring using an X‐ray medical diagnostic machine. POLYM. COMPOS., 37:1396–1406, 2016. © 2014 Society of Plastics Engineers     

Natural fiber blend—nylon 6 composites

In this study, engineering thermoplastic composites were prepared from natural fiber blend–filled nylon 6. Natural fiber blend from a mixture of kenaf, flax, and hemp fibers were added to nylon 6 using melt mixing to produce compounded pellets. The natural fibers/ nylon6 composites with varying concentrations of natural fibers (from 5 to 20 wt%) were prepared by injection molding. The tensile and flexural properties of the nylon 6 composites were increased significantly with the addition of the natural fiber blend. The maximum strength and modulus of elasticity for the nylon 6 composites were achieved at a natural fiber blend weight fraction of 20%. The Izod impact strength of composites decreased with the incorporation of natural fibers without any surface treatments and coupling agent. The melt flow index (MFI) also decreased with increasing natural fiber blend loading. The results of tensile and flexural modulus of elasticity (FMOE) are in accordance with the rheological data from the MFI measurements. The increase in the tensile and flexural properties indicated that efficient bonding occurred between the natural fibers and nylon 6. No fiber pullout was observed during the scanning electron microscopic analysis of the fracture surfaces. The higher mechanical results with lower density demonstrate that a natural fiber blend can be used as a sufficient reinforcing material for low‐cost, eco‐friendly composites in the automotive industry and in other applications such as the building and construction industries, packaging, consumer products, etc.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Evaluation of mechanical and thermal properties of tamarind seed filler reinforced vinyl ester composites

This article deals with the usage of tamarind seed filler (TSF) as reinforcement in vinyl ester (VE) composites. The composite plates have been fabricated by compression molding machine with TSFs of varying wt% from 5 to 50 as reinforcement material, and their properties such as tensile, flexural, impact, hardness, water absorption, heat deflection tests, and thermogravimetric analysis are studied. The mechanical properties of TSF reinforced VE composites are optimum at 15 wt% filler. The tensile strength and flexural strength of TSF‐VE composites are estimated to be around 34.1 and 121 MPa, respectively. The better impact strength of TSF‐VE composites is found to be 14.02 kJ/m², and barcol hardness can hold a value up to 42.33. Thermo gravimetric analysis and heat deflection test of TSF reinforced VE composite have improved the thermal stability. The fiber matrix interaction of the fractured mechanical testing specimen has been analyzed by scanning electron microscope. The TSF‐VE composites are used to fabricate the wheel hubcap of heavy‐duty buses, bus seat backrest cover, and silencer guard of the motorcycle. J. VINYL ADDIT. TECHNOL., 25:E114–E128, 2019. © 2019 Society of Plastics Engineers     

Evaluating the mechanical performance of supercritical CO2 fabricated polymide 6,6/PMMA,fiber reinforced composites

Recent advancements in SC CO₂ mediated synthesis and material processing have led to polymer‐polymer blends and composite materials with complex morphologies, exhibiting long‐range order and orientation on multiple length‐scales from the nanometer to the centimeter scale. The material under consideration in this work is a polyamide 6,6 (nylon)/poly (methyl methacrylate) (PMMA) fiber‐reinforced composite that was fabricated in a unique SC CO₂ assisted process. The tensile and flexural properties of these unique composites are studied and the evolution of damage and energy dissipation are monitored through cyclic loading and microscopic analysis of post‐stressed composite cross sections. It is shown that this morphology leads to improved flexural modulus and increased ultimate strength with only a small decrease in tensile modulus. These composites also exhibited significant improvements in stress distribution and load transfer without the use of fiber sizing agents for fiber/matrix compatibilization.     

Hybrid effect on mechanical properties of M40‐T300 carbon fiber reinforced Bisphenol A Dicyanate ester composites

Interply and intraply hybrid composites based on Bisphenol A Dicyanate ester (BADCy), high strength carbon fibers T300, and high modulus carbon fibers M40 were prepared by monofilament dip‐winding and press molding technique. The tensile, flexural, interlaminar shear properties and SEM analysis of the hybrid composites with different fiber content and fiber arrangement were investigated. The results indicated that the mechanical properties of intraply hybrid composites were mainly determined by fiber volume contents. When the ratio of fiber volume content was close to 1:1, the intraply hybrid composites possessed lowest tensile and flexural strength. The mechanical properties of interply hybrid composite mainly depended on the fiber arrangement, instead of the fiber volume contents. The hybrid composites using T300 fiber layout as outside layer possessed high flexural strength and low flexural modulus, which was close to that of T300/BADCy composites. The hybrid composites ([(M40)_x/(T300)_y]_S) using M40 fiber layout as outside layer and T300 fibers in the mid‐plane had high flexural modulus and interlaminar shear strength. POLYM. COMPOS., 2010. © 2010 Society of Plastics Engineers     

Physico-chemical,thermal, and mechanical properties of PLA-nHA nanocomposites: Effect of glass fiber reinforcement

In this study, tri-layered composites were prepared by reinforcing poly-lactic acid (PLA) nano-hydroxyapatite (n-HA) (1 and 5 wt%) and 20 mol% continuous phosphate glass fibers (PGF). Initially, the effect of addition of 1 and 5% n-HA on the structural, thermal, mechanical, and thermo-mechanical properties of 100% PLA was investigated. With 5 wt% n-HA addition the tensile modulus (TM), flexural modulus (FM), tensile strength (TS), and flexural strength (FS) of 100% PLA was improve by 14.9, 47.4, 6, and 32.9%, respectively. Whereas, the un-notched impact strength of the nanocomposites suffer 2% deterioration. However, T _g decreased by 0.3°C and T _c increased by 10°C as 5 wt% n-HA was added to 100% PLA. Afterwards, the 5% n-HA/PLA composite were reinforced with 20 mol% continuous PGF and the TM, FM, TS, and FS of the tri-layered composites were 162.6, 412.5, 28.4, and 157.4% higher as compared to 100%PLA. Furthermore, the storage modulus of the 1% n-HA-filled composites was 500 MPa lower than 100%PLA, while 5 wt% n-HA-filled composites showed similar storage modulus as 100% PLA. 5 wt% n-HA-filled composite showed the highest peak of loss modulus which may be attribute to the chain segment of PLA matrix after the incorporation of HA. Thus, n-HA and PGF reinforcement resulted in improved mechanical properties of the composites and have great potential as biodegradable bone fixation device with enhanced load-bearing ability.     

Relevance of graphene oxide as nanofiller for geometrical variation in unidirectional carbon fiber/epoxy composite

Curved geometry in unidirectional CFRP (UD-CFRP) demands ideal shape optimization to attain superior performance while maintaining the desired high strength to weight ratio. Herein, the effect of graphene oxide (GO) as the potential filler to improve the mechanical and thermal properties of flat and curved specimens of UD-CFRP was investigated. The GO was synthesized using Hummer's method and introduced in the epoxy resin by wet transfer technique. Three-point and four-point bending analysis of UD-CFRP showed maximum flexural strength and modulus at 0.3 wt% GO addition in UD-CFRP. The improved interfacial adhesion of 0.3 wt% GO incorporated UD-CFRP was realized by calculating storage modulus, reinforcement efficiency factor (r), C-factor, adhesion factor, cross-linking density, and glass transition temperature (T_g) from dynamic mechanical analyzer. Fracture analysis by scanning electron microscope showed the superior interlocking in carbon fiber, and epoxy polymer at 0.3 wt% GO addition.     

Incorporation of silicon dioxide nanoparticles at the carbon fiber‐epoxy matrix interphase and its effect on composite mechanical properties

Functionalized silicon dioxide nanoparticles (nano‐fSiO₂) were uniformly deposited on the surface of carbon fibers (CFs) using a coating process which consisted of immersing the fibers directly in a suspension of nano‐fSiO₂ particles and epoxy monomers in 1‐methyl‐2‐pyrrolidinone (NMP). The 0° flexural properties, 90° flexural properties, and Interlaminar shear strength (ILSS) mechanical properties of unidirectional epoxy composites made with nano‐fSiO₂+epoxy sized carbon fibers, with control fibers, and with epoxy‐only sized fibers were measured and compared. An obvious increase of the fiber/matrix adherence strength was obtained with the nano‐fSiO₂+epoxy coating. The nano‐fSiO₂+epoxy sized CF/epoxy composites showed a relative increase of 15%, 50%, and 22% in comparison to control fibers, for the Interlaminar shear strength, the 90^° flexural strength and the 90° flexural modulus, respectively, but little e difference was measured between the different systems for the 0° flexural properties. The observation of the fracture surfaces by scanning electron microscopy of composite fracture confirmed the improvement of the interfacially dependent mechanical properties. POLYM. COMPOS., 38:1474–1482, 2017. © 2015 Society of Plastics Engineers     

Grafting multi-elements hybrid polymer brushes on graphene oxide for epoxy composite with excellent flame retardancy

In this paper, a silicon-oxygen coupling agent (MPS) with a double bond is hydrolyzed with graphene oxide (GO) to obtain MPS-GO. The polymerization of MPS-GO with the phosphorus-containing monomer (HEPO) is initiated with 2,2′-Azobis(2-methylpropionitrile) (AIBN) to obtain multi-elements hybrid polymer brushes grafting graphene oxide (HM-GO). As a flame retardant, different amounts of HM-GO are added to obtain EP composites. In this system, the properties of composite flame retardant obviously increase with the increasing of HM-GO. The limiting oxygen index (LOI) value of composites with 4 wt% addition of HM-GO is 31.0%, while the LOI value of EP-0 is only 23.9%. And the peak heat release rate (PHRR) value is reduced from 515.8 W g⁻¹ of pure epoxy resin to 376.9 W g⁻¹. In addition, with the increase of HM-GO addition, the T_g value, flexural strength and flexural modulus of EP composites are improved. Through calculation, it is proved that the rising of T_g was due to the increase of crosslink density of the system. The flame retardant performance and mechanical properties of the composite materials are steadily improved, indicating that such flame retardants are dispersed well in the epoxy resin. HM-GO is an efficient macromolecular modified graphene oxide halogen-free flame retardant, which can improve both flame retardant properties and mechanical properties.     

Mechanical properties of talc‐ and (calcium carbonate)‐filled poly(vinyl chloride) hybrid composites

The main objective of this study was to investigate and compare the mechanical properties of poly(vinyl chloride) (PVC) composites filled with calcium carbonate (CaCO₃), talc, and talc/CaCO₃. Talc and CaCO₃ with different grades were incorporated into the PVC matrix. To produce the composites, the PVC resin, fillers, and other additives were first dry‐blended by using a laboratory mixer before being milled into sheets in a two‐roll mill. Test specimens were prepared by compression molding, after which the mechanical properties of the composites were determined. Single and hybrid filler loadings used were fixed at 30 phr (parts per hundred parts of resin). Talc‐filled composite showed the highest flexural modulus and the lowest impact strength, whereas uncoated, ground, 1‐μm CaCO₃ (SM 90) showed optimum properties in terms of impact strength and flexural modulus among all grades of CaCO₃. It was selected to combine with talc at different ratios in the hybrid composites. The impact strength of the hybrid composites gradually increased with increasing SM 90 content, but the flexural and tensile properties showed an opposite behavior. Hybrid (10 phr talc):(20 phr SM 90)‐filled PVC composite reached a synergistic hybridization with balanced properties in impact strength, as well as flexural and tensile properties. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

Synthesis and mechanical properties of unsaturated polyester based nanocomposites

Two classes of nanocomposites were synthesized using an unsaturated polyester resin as the matrix and sodium montmorillonite as well as an organically modified montmorillonite as the reinforcing agents. X‐ray diffraction pattern of the composites showed that the interlayer spacing of the modified montmorillonite expanded from 1.25 nm to 4.5 nm, indicating intercalation. Glass transition values of these composites increased from 72°C, in the unfilled unsaturated polyester, to 86°C in the composite with 10% organically modified montmorillonite. From Scanning Electron Microscopy, it is seen that the degree of intercalation/exfoliation of the modified montmorillonite is higher than in the unmodified one. The mechanical properties also supported these findings, since in general, the tensile modulus, tensile strength, flexural modulus, flexural strength and impact strength of the composites with modified montmorillonite were higher than the corresponding properties of the composites with unmodified montmorillonite. The tensile modulus, tensile strength, flexural modulus and flexural strength values showed a maximum, whereas the impact strength exhibited a minimum at approximately 3–5 wt% modified montmorillonite content. These results imply that the level of exfoliation may also exhibit a maximum with respect to the modified montmorillonite content. The level of improvement in the mechanical properties was substantial. Adding only 3 wt% organically modified clay improved the flexural modulus of unsaturated polyester by 35%. The tensile modulus of unsaturated polyester was also improved by 17% at 5 wt% of organically modified clay loading.     

Effect of in situ surface‐modified nano‐SiO2 on the thermal and mechanical properties and crystallization behavior of nylon 1010

Nylon 1010 composites filled with two types of surface‐modified SiO₂ nanoparticles (RNS and DNS) were prepared by melt blending. The mechanical properties of the composites were evaluated. The influences of the surface‐modified nano‐SiO₂ on the thermal stability, crystallization behavior, and microstructure of nylon 1010 were investigated by thermogravimetric analysis, differential scanning calorimetry (DSC), X‐ray diffraction, and transmission electron microscopy. And the interfacial interactions between the fillers and polymer matrix were examined using a Fourier transformation infrared spectrometer. It was found that the addition of the surface‐modified nano‐SiO₂ had distinct influences on the thermal stability, mechanical properties, and crystallization behavior of nylon 1010. RNS and DNS as the fillers had different effects on the mechanical properties of nylon 1010. The composites filled with RNS at a mass fraction of 1–5% showed increased break elongation, Young's modulus, and impact strength but almost unchanged or even slightly lowered tensile strength than the unfilled matrix. The DNS‐filled nylon 1010 composites had obviously decreased tensile strength, whereas the incorporation of DNS also contributed to the increase in the Young's modulus of nylon 1010, but less effective than RNS. Moreover, the nylon 1010 composites had better thermal stability than the neat polymer matrix, and the composites filled with RNS were more thermally stable than those filled with DNS. The difference in the crystallinity of neat nylon 1010 and its composites filled with RNS and DNS was subtle, although the surface‐modified nano‐SiO₂ could induce or/and stabilize the γ‐crystalline formation of nylon 1010. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A comparative analysis of woven jute/glass hybrid polymer composite with and without reinforcing of fly ash particles

The objective of this research article is to compare the mechanical and tribological properties of jute‐glass‐fiber‐reinforced epoxy (J‐G‐E) hybrid composites with and without fly ash particulate filler. A dry hand lay‐up technique is used to fabricate all the laminates. The properties including flexural strength, tensile strength, flexural modulus, and erosion behavior of all the composites are evaluated as per American Society for Testing and Materials (ASTM) standards. The fly ash particulate‐filled hybrid composite shows a better mechanical and tribological property. The maximum flexural strength and flexural modulus are obtained for GJGJ+ 5 wt% fly ash filler epoxy composites. Whereas the maximum tensile strength is obtained for GJJG+ 10 wt% fly ash filler epoxy composites. Scanning Electron Microscopy (SEM) analysis also has been carried out to categorize mechanical and tribological behavior of composites. POLYM. COMPOS. 37:658–665, 2016. © 2014 Society of Plastics Engineers     

Mechanical and thermal properties of hierarchical composites enhanced by pristine graphene and graphene oxide nanoinclusions

Epoxy resin nanocomposites incorporated with 0.5, 1, 2, and 4 wt % pristine graphene and modified graphene oxide (GO) nanoflakes were produced and used to fabricate carbon fiber‐reinforced and glass fiber‐reinforced composite panels via vacuum‐assisted resin transfer molding process. Mechanical and thermal properties of the composite panels—called hierarchical graphene composites—were determined according to ASTM standards. It was observed that the studied properties were improved consistently by increasing the amount of nanoinclusions. Particularly, in the presence of 4 wt % GO in the resin, tensile modulus, compressive strength, and flexural modulus of carbon fiber (glass fiber) composites were improved 15% (21%), 34% (84%), and 40% (68%), respectively. Likewise, with inclusion of 4 wt % pristine graphene in the resin, tensile modulus, compressive strength, and flexural modulus of carbon fiber (glass fiber) composites were improved 11% (7%), 30% (77%), and 34% (58%), respectively. Also, thermal conductivity of the carbon fiber (glass fiber) composites with 4% GO inclusion was improved 52% (89%). Similarly, thermal conductivity of the carbon fiber (glass fiber) composites with 4% pristine graphene inclusion was improved 45% (80%). The reported results indicate that both pristine graphene and modified GO nanoflakes are excellent options to enhance the mechanical and thermal properties of fiber‐reinforced polymeric composites and to make them viable replacement materials for metallic parts in different industries, such as wind energy, aerospace, marine, and automotive. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40826.     

Short glass fiber reinforced ABS and ABS/PA6 composites: Processing and characterization

In this study acrylonitrile‐butadiene‐styrene (ABS) terpolymer was reinforced with 3‐aminopropyltrimethoxysilane (APS)‐treated short glass fibers (SGFs). The effects of SGF concentration and extrusion process conditions, such as the screw speed and barrel temperature profile, on the mechanical properties of the composites were examined. Increasing the SGF concentration in the ABS matrix from 10 wt% to 30 wt% resulted in improved tensile strength, tensile modulus and flexural modulus, but drastically lowered the strain‐at‐break and the impact strength. The average fiber length decreased when the concentration of glass fibers increased. The increase in screw speed decreased the average fiber length, and therefore the tensile strength, tensile modulus, flexural modulus, and impact strength were affected negatively and the strain‐at‐break was affected positively. The increase in extrusion temperature decreased the fiber length degradation, and therefore the tensile strength, tensile modulus, flexural modulus, and impact strength increased. At higher temperatures the ABS matrix degraded and the mechanical strength of the composites decreased. To obtain a strong interaction at the interface, polyamide‐6 (PA6) at varying concentrations was introduced into the ABS/30 wt% SGF composite. The incorporation and increasing amount of PA6 in the composites broadened the fiber length distribution (FLD) owing to the low melt viscosity of PA6. Tensile strength, tensile modulus, flexural modulus, and impact strength values increased with an increase in the PA6 content of the ABS/PA6/SGF systems due to the improved adhesion at the interface, which was confirmed by the ratio of tensile strength to flexural strength as an adhesion parameter. These results were also supported by scanning electron micrographs of the ABS/PA6/SGF composites, which exhibited an improved adhesion between the SGFs and the ABS/PA6 matrix. POLYM. COMPOS. 26:745–755, 2005. © 2005 Society of Plastics Engineers