Enhancing the mechanical properties of 3D printed polylactic acid using nanocellulose

We report here a systematic investigation of the mechanical properties of polylactic acid (PLA) processed by fused filament fabrication (FFF) 3D printing vs PLA processed by compression molding. Our results show that the tensile strength and modulus of FFF-PLA is 49% and 41% lower, respectively, than compression molded samples of PLA. We also demonstrate here an approach to augment the mechanical properties of 3D printed PLA using nanocellulose. Incorporation of a small quantity (1 wt%) of cellulose nanofibers (CNF) was found to enhance the tensile strength and modulus of 3D printed PLA by 84% and 63%, respectively. X-ray microtomography was used to probe the morphology of 3D printed PLA and PLA/CNF composites. 3D printed PLA/CNF composites had significantly lesser voids as compared to neat 3D printed PLA. Differential scanning calorimetry study revealed that CNF can accelerate the nucleation and crystallization of 3D printed PLA leading to enhanced crystallinity. The thermal stability of 3D printed PLA/CNF composites was not compromised by the addition of CNF. The enhanced mechanical properties of 3D printed PLA/CNF composites can be ascribed to higher crystallinity and lesser defects.     

Special morphology and its role in mechanical enhancement of linear low‐density polyethylene/multiwalled carbon nanotubes composites

In this work, multiwalled carbon nanotubes (MWCNTs), as reinforcing agent, were blended with linear low‐density polyethylene (LLDPE), then molded by hot compression molding to prepare LLDPE/MWCNTs composites. Tensile tests indicate that the strength, Young's modulus, and toughness are all improved for LLDPE/MWCNTs composites containing 1 and 3 wt % MWCNTs. Compared with LLDPE, the Young's modulus of LLDPE/MWCNTs composites rises from 144.8 to 270.8 MPa at 1 wt % MWCNTs content. At the same time, increases of 18.5% in tensile strength and 16.6% in yield strength are achieved. Additionally, its toughness is enhanced by 26.7% than that of LLDPE. Microstructure characterizations, including differential scanning calorimetry, X‐ray diffraction, and scanning electron microscopy were performed to investigate the variations of microstructure and further to establish the relationship between microstructure and mechanical properties. Homogeneous dispersion of MWCNTs, network formation, and development of an oriented nanohybrid shish‐kebab structure contribute to the enhanced strength and toughness. The increased crystallinity is beneficial to the reinforcement and increased modulus. Additionally, the thermal stability of the LLDPE/MWCNTs composites is enhanced as well. This work suggests a promising routine to optimize polymer/MWCNTs composites by tailoring the structural development. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45525.     

Effect of alkali treatment on properties of unidirectional isora fibre reinforced epoxy composites

Abstract

Unidirectional isora fibre reinforced epoxy composites were prepared by compression moulding. Isora is a natural bast fibre separated from Helicteres isora plant by retting process. The effect of alkali treatment on the properties of the fibre was studied by scanning electron microscopy (SEM), IR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mechanical properties such as tensile strength, Young's modulus, flexural strength, flexural modulus and impact strength of the composites containing untreated and alkali treated fibres have been studied as a function of fibre loading. The optimum fibre loading for tensile properties of the untreated fibre composite was found to be 49% by volume and for flexural properties the loading was optimised at ～45%. Impact strength of the composite increased with increase in fibre loading and remained constant at a fibre loading of 54·5%. Alkali treated fibre composite showed improved thermal and mechanical properties compared to untreated fibre composite. From dynamic mechanical analysis (DMA) studies it was observed that the alkali treated fibre composites have higher E' and low tan δ maximum values compared to untreated fibre composites. From swelling studies in methyl ethyl ketone it was observed that the mole percentage of uptake of the solvent by the treated fibre composites is less than that by the untreated fibre composites. From these results it can be concluded that in composites containing alkalised fibres there is enhanced interfacial adhesion between the fibre and the matrix leading to better properties, compared to untreated fibre composites.     

Effect of clay type and polymer matrix on microstructure and tensile properties of PLA/LLDPE/clay nanocomposites

Polylactide (PLA)/linear low‐density polyethylene (LLDPE), (PLA/LLDPE), blends and nanocomposites were prepared by melt mixing process with a view to fine tune the properties. Two different commercial‐grade nanoclays, Cloisite® 30B (30B) and Cloisite® 15A (15A) were used. A terpolymer of ethylene, butylacrylate (BA) and glycidylmethacrylate (GMA) was used as a reactive compatibilizer. The influence of type of clay on the morphology and mechanical properties of two PLA‐rich and LLDPE‐rich blend systems was studied. Morphological analysis using X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy revealed that the organoclay layers were dispersed largely at the interface of PLA/LLDPE. Decreasing the PLA content changed the morphology from droplet‐in matrix to coarse co‐continuous. In comparison with 30B, due to less affinity of 15A towards compatibilizer and PLA phase, the reduction of the size of dispersed phase was less than that of the equivalent 30B composites. The mechanical results demonstrated that the composites containing both types of organoclay exhibited higher modulus but lower elongation and tensile strength as compared to the neat blends. The injection molded nanocomposites were shown to have the sequential fracture behavior during tensile test. The tensile testing results on the neat blends and nanocomposites showed significant increase in elongation at break and decrease in the modulus as compared with the neat PLA. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 749‐758, 2013     

聚己内酯3D打印成型工艺研究及力学性能分析

以聚己内酯（PCL）为材料,采用实验方法,研究了成型温度和打印层高对PCL制品翘曲变形的影响。通过三维（3D）打印制备PCL样条,表征了3D打印PCL的力学性能,并与注射成型进行对比。结果表明,随着成型温度的升高和打印层高的增加,PCL制品的翘曲变形量呈现出先增加后减小的趋势;PCL 的3D打印制品的拉伸强度、弯曲强度和断裂伸长率均高于传统注射成型工艺。     

Effect of zircon and anatase titanium dioxide nanoparticles on glass fibre reinforced epoxy with mechanical and morphological studies

In recent years, researchers have been interested in incorporating inorganic nanoparticles into thermosetting epoxy composites to improve their mechanical properties. This research explores the diffusion of ball milled zircon (ZrSiO₄) and anatase TiO₂ nanoparticles with glass fibre reinforced epoxy polymer (GFRP) composites at the same weight percentages (0:0, 2.5:2.5, 5:5, and 7.5:7.5) to improve mechanical properties. The ZrSiO₄ and TiO₂ nanoparticles were prepared by an ultrasonic liquid processor, and composites were fabricated using the compression molding technique. The void percentage was calculated from the theoretical and measured densities of composites. Mechanical tests were conducted in accordance with ASTM standards. The particle sizes of zircon and titanium dioxide were calculated as 70.5 nm and 64.5 nm, respectively, using field emission scanning electron microscopy (FESEM), which reveals the fibre pullout, damaged interfaces, filler dispersion, and voids in specimens. The chemical composition, crystalline structure, and size were determined using X-ray diffraction (XRD). It was found that the GFRP composite with Zircon and TiO₂ incorporated at a concentration of 5:5 wt% has a greater tensile strength of 74.34%, a tensile modulus of 18.14%, a flexural strength of 33.55%, a flexural modulus of 33.61%, a shore "D" hardness of 4.66%, and a capacity to absorb energy of 61.14% in notched specimens with neat GFRP. With filler addition, the percentage of elongation at failure in the 5:5 wt percent for the tensile test is 44.36%, and the flexural test is 24.38% higher than the neat sample. Hence, this work improves the GFRP composites' mechanical and structural properties.     

Fibre-reinforced lightweight engineered cementitious composites for 3D concrete printing

While the 3D printing technology for cementitious composites has developed rapidly, a combination of 3DP technology and lightweight engineered cementitious composites (LWECCs) could improve many aspects of the construction industry. In this study, a fibre-reinforced high-performance LWECC for extrusion-based printing was proposed. First, six LWECCs were prepared, incorporating two kinds of hollow glass microspheres (HGMs) in varying replacement ratios of fly ash (FA) at 60 wt%, 80 wt%, and 100 wt%. In addition, polyvinyl alcohol (PVA) fibre was introduced given its shrinkage resistance and improvement in printability performance. Thereafter, fresh property (slump loss and setting time), unconfined compression strength (UCS), and flexural strength experiments thoroughly investigated the optimised LWECC design, which was later calibrated for the printing procedure via a printability assessment, including extrudability and buildability. The UCS, flexural strength, and densities of the printed and cast specimens were compared. Lastly, a microstructural investigation using a scanning electron microscope described the reinforcement mechanism of PVA fibre upon the performance of the printed structures and HGMs. The addition of HGMs significantly improve the lightweight property that reaches a value at 1384 kg/m³ but inevitably negates mechanical properties. The printed LWECC obtains 33.6 MPa for UCS and 9.29 MPa for flexural strength. When the printed filament was perpendicular to loading direction, superior toughness was observed, creating a 63% and 40% increase for UCS and flexural strength, respectively.     

Thermal and mechanical properties of polyamide 12/graphene nanoplatelets nanocomposites and parts fabricated by fused deposition modeling

The printable polyamide 12 (PA12) nanocomposite filaments with 6 wt % graphene nanoplatelets (GNPs) for fused deposition modeling (FDM) were prepared by melting compounding and smoothly printed via a commercial FDM three‐dimensional (3D) printer. The thermal conductivity (λ) and elastic modulus (E) of 3D printed PA12/GNPs parts along to the printing direction had an increase by 51.4% and 7% than that of compression molded parts, which is due to the GNPs preferentially aligning along to the printing direction. Along with these improved properties, ultimate tensile strength of 3D printed PA12/GNPs parts was well maintained. These results indicate that FDM is a new way to achieve PA12/GNPs parts with enhanced λ over compression moulding, which could contribute to realize efficient and flexible heat management for a wide range of applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45332.     

Reactive compatibilization and performance evaluation of miscanthus biofiber reinforced poly(hydroxybutyrate‐co‐hydroxyvalerate) biocomposites

Dicumyl peroxide (DCP) initiated reactive compatibilization of poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV)/miscanthus fibers (70/30 wt %) based biocomposite was prepared in a twin screw extruder followed by injection molding. In the presence of DCP, both the flexural and the tensile strength of the PHBV/miscanthus composites were appreciably higher compared with PHBV/miscanthus composite without DCP as well as neat PHBV. The maximum tensile strength (29 MPa) and flexural strength (51 MPa) were observed in the PHBV/miscanthus composite with 0.7 phr DCP. The enhanced flexural and tensile strength of the PHBV/miscanthus/DCP composites are attributed to the improved interfacial adhesion by free radical initiator. Unlike flexural and tensile strength, the modulus of the PHBV/miscanthus/DCP composites was found to slightly lower than the PHBV/miscanthus composite. The modulus difference in the PHBV/miscanthus composite with and without DCP has good agreement with the observed crystallinity. However, the flexural and tensile modulus of all the prepared biocomposites was at least two fold higher than the neat PHBV. The storage modulus value of the PHBV/miscanthus and PHBV/miscanthus/DCP biocomposites follows similar trend like tensile and flexural modulus. The melting temperature and crystallization temperature of PHBV/DCP and PHBV/miscanthus/DCP samples were considerably lower compared with the neat PHBV and PHBV/miscanthus composites. The surface morphology revealed that the PHBV/miscanthus/DCP composites have good interface with less fiber pull‐outs compared with the corresponding counterpart without DCP. This suggests that the compatibility between the matrix and the fibers is enhanced after the addition of peroxide initiator. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44860.     

Sunflower seed cake as reinforcing filler in thermoplastic composites

Dimensional stability, mechanical properties, and melting and crystallization behavior of polypropylene composites filled with sunflower seed cake (SSC) were investigated. Injection molded composites were prepared from the SSC flour and polypropylene with and without maleic anhydride‐grafted polypropylene (MAPP) at 30, 40, 50, and 60 wt % contents of the SSC flour. Twenty‐eight days thickness swelling and water absorption values of the specimens increased by 43 and 56% as the filler content increased from 30 to 60 wt %, respectively. The flexural modulus of the polypropylene composites increased from 3157 to 4363 MPa as the SSC flour increased from 30 to 60 wt %. The maximum flexural strength 38.4 MPa was observed for 40 wt % SSC flour filled specimens. However, further increment in the SCC flour decreased the flexural strength to 31.4 MPa. The tensile strength of the specimens decreased from 22.5 to 14 MPa while the tensile modulus increased from 3023 to 3677 MPa as the SSC flour increased from 30 to 60 wt %. The dimensional stability and mechanical properties of the composites were significantly improved by the incorporation of the coupling agent (MAPP). The effect of the MAPP addition was more pronounced for the strength than for the modulus. The melting temperature and degree of crystallinity of the neat polypropylene decreased with increasing content of the SSC flour. The degree of crystallinity of filled composites considerably increased with the incorporation of the MAPP. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Measurement of the mechanical and dynamic properties of 3D printed polylactic acid reinforced with graphene

In this paper, three-dimensional (3D) printing system based on fused deposition modeling (FDM) is used for the fabrication of polylactic acid (PLA) specimens with and without graphene and to measure their dynamic mechanical properties. In particular, 3D printed PLA/graphene nanocomposites containing 10wt% graphene in PLA matrix were characterized by compression tests, cyclic compression tests, nanoindentation and modal tests. The results of the mechanical tests reveal that the incorporation of multifunctional graphene has improved the modulus, the strength and the hardness of the 3D printed nanocomposites. The damping as calculated by cyclic compression and modal tests was substantially increased compared to neat PLA samples.     

Composites of poly(lactic acid)/poly(butylene adipate-co-terephthalate) blend with wood fiber and wollastonite: Physical properties,morphology, and biodegradability

Poly(lactic acid) (PLA) was first melt blended with five weight percentages (10–50 wt %) of poly(butylene adipate-co-terephthalate) (PBAT) on a twin-screw extruder and then injection molded. The blend at 30 wt % PBAT exhibited the highest impact strength and elongation-at-break without phase inversion. The 70/30 (w/w) PLA/PBAT blend with high toughness improvement was selected for preparing both single and hybrid composites using an organic filler, wood fiber (WF) and inorganic filler, wollastonite (WT) with a fix total loading at 30 parts per hundred of resin (phr) throughout the experiment. Five WF/WT (phr/phr) ratios for the composites were 30/0, 10/20, 15/15, 20/10, and 0/30. The prepared composites were investigated for the mechanical and thermal properties, melt flow index (MFI), morphology, flammability, water uptake, and biodegradability as a function of composition. All the composites showed a filler-dose-dependent decrease in the impact strength, elongation-at-break, MFI, and thermal stability, but an increase in the tensile and flexural modulus, tensile and flexural strength, antidripping ability, and water uptake compared with the neat blend. The addition of WF and WT was also found to promote the biodegradability of the PLA/PBAT blend. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47543.     

Modification of polymers using multilayered “smart pellet” additives: Part II

A magnesium-based inorganic whisker was compounded with polypropylene and with polysulfone (FP/PP and FPSF/PP^*, respectively) and then multilayered into alternating structures with unfilled polypropylene (PP). These multilayered materials were cut into FP/PP and FPSF/PP^* “smart pellets”, which were then added to polypropylene matrix polymer as masterbatches to deliver potential reinforcement to injection molded parts. The morphologies of both the smart pellets and the composites produced with them were studied by scanning electron microscopy (SEM). The inorganic whiskers were found to be aligned in the machine direction in the smart pellets. Mechanical properties of the composites were investigated by performing tensile, flexural, and impact strength tests. Inorganic whiskers combined with PSF offered higher flexural modulus in comparison to those via conventional blending; no significant improvement was observed in tensile modulus or impact strength of these composites.     

Preparation and properties of successive alkali treated completely biodegradable short jute fiber reinforced PLA composites

The natural fiber reinforced biodegradable polymer composites were prepared with short jute fiber as reinforcement in PLA (Poly lactic acid) matrix. The short jute fiber is successively treated with NaOH at various concentrations (5%, 10%, and 15%) and H₂O₂. The composites were prepared with untreated and treated short jute fibers at different weight proportions (up to 25%) in PLA and investigated for mechanical properties. The results showed that the composite with successive alkali treated jute fiber at 10% NaOH and H₂O₂ with 20% fiber loading has shown 18% higher flexural strength than neat PLA and untreated jute/PLA composite. The flexural modulus of the composite at 25% fiber loading was 125% and 110% higher than that of composites with untreated fibers and neat PLA, respectively. The impact strength of composite with untreated fibers at higher fiber weight fraction was 23% high as compared to neat PLA and 26% high compared to composite with treated fibers. The water absorption was more for untreated jute/PLA composite at 25% fiber loading than all other composites. The composite with untreated fibers has high thermal degradation compared with treated fibers but lower than that of pure PLA matrix. The enzymatic environment has increased the rate of degradation of composites as compared to soil burial. Surface morphology of biodegraded surfaces of the composites were studied using SEM method. POLYM. COMPOS., 37:2160–2170, 2016. © 2015 Society of Plastics Engineers     

Injection‐molded high‐density polyethylene–hydroxyapatite–aluminum oxide hybrid composites for hard‐tissue replacement: Mechanical,biological, and protein adsorption behavior

In this article, we report the mechanical and biocompatibility properties of injection‐molded high‐density polyethylene (HDPE) composites reinforced with 40 wt % ceramic filler [hydroxyapatite (HA) and/or Al₂O₃] and 2 wt % titanate as a coupling agent. The mechanical property measurements revealed that a combination of a maximum tensile strength of 18.7 MPa and a maximum tensile modulus of about 855 MPa could be achieved with the injection‐molded HDPE–20 wt % HA–20 wt % Al₂O₃ composites. For the same composite composition, the maximum compression strength was determined to be 71.6 MPa and the compression modulus was about 660 MPa. The fractrography study revealed the uniform distribution of ceramic fillers in the semicrystalline HDPE matrix. The cytocompatibility study with osteoblast‐like SaOS2 cells confirmed extensive cell adhesion and proliferation on the injection‐molded HDPE–20 wt % HA–20 wt % Al₂O₃ composites. The cell viability analysis with the 3(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay revealed a statistically significant difference between the injection‐molded HDPE–20 wt % HA–20 wt % Al₂O₃ composites and sintered HA for various culture durations of upto 7 days. The difference in cytocompatibility properties among the biocomposites is explained in terms of the difference in the protein absorption behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

High density polyethylene/micro calcium carbonate composites: A study of the morphological,thermal, and viscoelastic properties

High density polyethylene (HDPE) with micro calcium carbonate (CaCO₃) masterbatch was pelletized by using a twin screw extruder and different ASTM specimens were molded by an injection molding machine. The morphology of the composites was characterized by scanning electron microscopy (SEM) and Image Analysis software. The dispersion and interfacial interaction between CaCO₃ and the polymer matrix were also investigated by SEM. The thermal properties of HDPE and its composites were investigated by differential scanning calorimetry (DSC). The crystallization process of the composites samples was found to be slightly different than that of the neat HDPE. Otherwise, the presence of CaCO₃ did not have a considerable effect on the melting behavior of the composites. Thermogravimetric analysis (TGA) revealed that the composites had better thermal stability than the neat HDPE resin as indicated by a higher temperature of 50% weight loss (T_50%) for the composites as compared to that of the neat resin. The viscoelastic properties of the composites and HDPE were also investigated via torsional and rotational techniques. The presence of CaCO₃ increased the shear modulus at low frequency of the composites at 80°C over that of the neat resin. However, at higher frequencies, the difference between the neat resin and the composites' shear modulus was less than that at low frequencies. The complex viscosity of the composite increased upon the addition of CaCO₃. However, the shear sensitivities of the neat resin and the microcomposite were similar. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Water-Blown Rigid Biofoams from Soy-Based Biopolyurethane and Microcrystalline Cellulose

A novel soy-based polyurethane biofoam (BioPU) from two polyols (soybean oil-derived polyols SOPEP and petrochemical polyol Jeffol A-630?=?1:1 in weight) and poly (diphenylmethane diisocyanate) (pMDI) has been prepared by using a free-rise method with water as a blowing agent, and microcrystalline cellulose (MCC) as a reinforcement. The photographs of the samples show that the biofoams have similar appearances, and the cell morphology of the resulting biofoams was examined by scanning electron microscope. Density of the composites decreased as a result of increase in MCC content. FTIR study exhibited characteristic peaks for MCC and BioPU. Mechanical properties such as compressive strength, compressive modulus, flexural strength and flexural modulus of the samples were substantially improved with the increase in MCC content. Similarly, improvements in glass transition temperature (T _g) and storage modulus around and after T _g of the neat biofoam were also observed with the composites. Dynamic mechanical analysis results showed an improvement in mechanical properties as well as better thermal stability of the composites over the neat biofoam. Thermogravimetric analysis showed improved thermal stability of the biofoams reinforced with MCC. This research has provided a simple method for preparing the biofoam, while exploring the potential of substituting up to 50?% of the petroleum-based polyol in biofoam applications.     

Pinecone particles filled polybenzoxazine composites: Thermomechanical and mechanical properties

In the current study, 1 wt%, NaOH treated pine cone (ATPC) particles composites with bisphenol-A aniline based benzoxazine (BA-a) matrix were prepared by isothermal compression method. Ultimate impacts of ATPC reinforcement on the thermomechanical, tensile, flexural, and impact properties of the composites were studied by using a dynamic mechanical analyzer (DMA), a Universal testing machine, and a Tinius-Olsen impact device, respectively. The thermal stability of ATPC particles was remarkably increased, TGA confirmed that particles will not be degraded during the curing. The DMA results of 30 wt% ATPC reinforced composites confirmed that the glass transition temperature, storage modulus, and loss modulus were 22 ° C, 2510, and 250 MPa higher than the neat matrix, respectively. In addition, the impact strength of the 30 wt% ATPC reinforced composites was nearly 3 times higher than the neat matrix, which confirmed that the matrix's brittleness is reduced, similar observation was confirmed by the Brostow and coworkers empirical model. Moreover, a gradual rise in the tensile and flexural properties was also recorded. We can easily conclude from the studied parameters that the ATPC particles can be used as a sustainable agro-waste in polymeric composites.     

The effects of hybrid fillers on thermal,mechanical, physical,and antimicrobial properties of ultrahigh‐molecular‐weight polyethylene‐reinforced composites

The effects of hybrid filler of zinc oxide and chitosan (chitosan–ZnO) on thermal, flexural, antimicrobial, chemical resistance, and hardness properties of ultrahigh‐molecular‐weight polyethylene (UHMWPE) composites with varying concentration of zinc oxide (ZnO) and further hybridized by chitosan (CS) were successfully studied. The composites were prepared using mechanical ball milling and followed by hot compression molding. The addition of ZnO to the UHMWPE matrix had lowered the melting temperature (T _m) of the composite but delayed its degradation temperature. Further investigation of dual filler incorporation was done by the addition of chitosan to the UHMWPE/ZnO composite and resulted in the reduction of UHMWPE crystallization. The flexural strength and modulus had a notably high improvement through ZnO addition up to 25 wt% as compared to neat UHMWPE. However, the addition of chitosan had resulted in lower flexural strength than that of 12 wt% ZnO UHMWPE composite but still higher than that of neat UHMWPE. It was experimentally proven that the incorporation of ZnO and chitosan particles within UHMWPE matrix had further enhanced the antimicrobial properties of neat UHMWPE. Chemical resistance was improved with higher ZnO content with a slight reduction of mass change after the incorporation of chitosan. The hardness value increased with ZnO addition but higher incorporation of chitosan had lowered the hardness value. These findings have significant implications for the commercial application of UHMWPE based products. It appears that these hybrid fillers (chitosan–ZnO)‐reinforced UHMWPE composites exhibit superior overall properties than that of conventional neat UHMWPE. POLYM. COMPOS., 38:1689–1697, 2017. © 2015 Society of Plastics Engineers     

Carbon‐fiber‐reinforced acrylonitrile–styrene–acrylate composites: Mechanical and rheological properties and electrical resistivity

The aim of this study was to improve the mechanical properties of an acrylonitrile–styrene–acrylate copolymer (ASA) with the help of carbon fibers (CFs). Additionally, the effects of the CFs on the morphology, rheological properties, dynamical mechanical properties, electrical resistivity, and heat resistance of the ASA composites were studied with scanning electron microscopy, rotational rheometry, and dynamic thermomechanical analysis (DMA). The mechanical properties of the ASA composites were enhanced largely by the CFs. The maximum tensile strength of the ASA/CF composites reached 107.2 MPa. The flexural strength and flexural modulus also reached 162.7 MPa and 12.4 GPa, respectively. These findings were better than those of neat ASA; this was attributed to the excellent interfacial adhesion between the CFs and ASA resin. Rheological experiments proved that the viscosity and storage modulus (G′) values of the ASA/CF composites did not increase until the CF content reached 20%. The DMA outcomes confirmed that the glass‐transition temperature of the ASA composites was elevated from 120.6 to 125°C. Importantly, the G′ values of the composites with 20 and 30% CFs showed a large increase during heating. In addition, the ASA/CF composites exhibited excellent conductivity and heat resistance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43252.