Fabrication and mechanical properties of glass fiber‐reinforced wood plastic hybrid composites

To fully utilize the resource in the municipal solid waste (MSW) and improve the strength and toughness of wood plastic composites, glass fiber (GF)‐reinforced wood plastic hybrid composites (GWPCs) were prepared through compounding of recycled high‐density polyethylene (HDPE) from MSW, waste wood fibers, and chopped GF. Mechanical tests of GWPCs specimens with varying amounts of GF content were carried out and the impact fractured surface of GWPCs was observed through scanning electron microscope (SEM). The tensile strength of GWPCs and the efficiency coefficient values were predicted by Kelly‐Tyson method. The results indicated that the tensile strength and impact strength of GWPCs could be improved simultaneously by adding type L chopped GF (L‐GF), and would be dropped down when type S chopped GF (S‐GF) was included. The tensile strength of GWPCs was well accordant with the experimental result. The efficiency coefficient values of S‐GF and L‐GF are ?0.19 and 0.63, respectively. Inspection of SEM micrographs indicated that L‐GF had achieved full adhesion with the plastic matrix through addition of maleic anhydride‐g‐polyethylene. The main fracture modes of GWPCs included pullout of GF, broken of matrix, and interfacial debonding. Because of the synergistic effects between hybrid components in GF/wood fiber/HDPE hybrid system, a special 3D network microstructure was formed, which was the main contribution to the significant improvement in the tensile strength and impact strength of L‐GF‐reinforced hybrid composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

PVC／木粉复合材料抗冲改性研究

用甲基丙烯酸、丙烯酸丁酯、甲基丙烯酸甲酯三元共聚物P（MAA—BA—MMA）对木粉进行预处理,再利用CPE、ACR和nano—CaCO3对PVC／木粉复合材料进行增韧改性。结果表明,木粉经P（MAA—BA—MMA）预处理后,使用ACR增韧时效果最好,其拉伸强度、弯曲强度、冲击强度和断裂伸长率分别提高了7．97％、5．26％、68．85％和571．26％。SEM结果表明,木粉预处理后再增韧,复合材料界面模糊,断面呈一定的韧性断裂特征。     

Novel coupling agents for PVC/wood‐flour composites *

Effective interfacial adhesion between wood fibers and plastics is crucial for both the processing and ultimate performance of wood–plastic composites. Coupling agents are added to wood–plastic composites to promote adhesion between the hydrophilic wood surface and hydrophobic polymer matrix, but to date no coupling agent has been reported for PVC/wood‐fiber composites that significantly improved their performance and was also cost‐effective. This article presents the results of a study using chitin and chitosan, two natural polymers, as novel coupling agents for PVC/wood‐flour composites. Addition of chitin and chitosan coupling agents to PVC/wood‐flour composites increased their flexural strength by ～20%, their flexural modulus by ～16%, and their storage modulus by ～33–74% compared to PVC/wood‐flour composite without the coupling agent. Significant improvement in composite performance was attained with 0.5 wt% of chitosan and when 6.67 wt% of chitin was used. J. VINYL ADDIT. TECHNOL., 11:160–165, 2005. © 2005 Society of Plastics Engineers     

Effects of impact modifiers on the properties of rigid PVC/wood‐fiber composites

This study examined the effects of impact modifier types and addition levels on the mechanical properties of rigid PVC/wood‐fiber composites. The impact resistance of rigid PVC/wood‐fiber composites depends strongly on the type and content of impact modifier. With the proper choice of modifier type and concentration, the impact strength of rigid PVC/wood‐fiber composites can be significantly improved without degrading the tensile properties. Methacrylate‐butadiene‐styrene and all‐acrylic modifiers performed in a similar manner and were more effective and efficient in improving the impact resistance of rigid PVC/wood‐fiber composites than the chlorinated polyethylene modifier.     

Effects of copper amine treatment on mechanical properties of PVC/wood‐flour composites

Copper amine–treated wood flour was added to PVC [poly(vinyl chloride)] matrix in order to manufacture PVC/wood‐flour composites. Effects of copper treatments on the mechanical properties of PVC‐wood composites were evaluated. Unnotched impact strength, flexural strength, and flexural toughness of the composites were significantly improved by the wood‐flour copper treatment. The optimum copper concentration range was 0.2 to 0.6 wt% of wood flour. Fractured surfaces were examined by using scanning electron microscopy (SEM) combined with energy‐dispersive spectroscopy (EDS). PVC/wood interfacial debonding was the main fracture mode of untreated wood‐flour composites, whereas wood‐particle pullout and breakage dominating the fractured surfaces of copper‐treated wood‐flour composites. On the fractured surfaces, more PVC could be found on the exposed copper‐treated wood particles than on untreated wood, a result suggesting improved PVC‐wood interfacial adhesion after copper treatments. J. Vinyl Addit. Technol. 10:70–78, 2004. © 2004 Society of Plastics Engineers.     

Studies on mechanical characterization and water resistance of glass fiber/thermoplastic polymer bionanocomposites

This experimental work is aimed at studying the performance of rice husk flour/glass fiber reinforced high density polyethylene hybrid nanocomposites. To meet this objective, the nanoclay was compounded with high density polyethylene (HDPE), rice husk flour (RF), glass fiber, and coupling agent in an internal mixer; then, the samples were fabricated by injection molding. The concentration was varied from 0 to 6 per hundred compounds for nanoclay and from 0 to 15% for glass fiber, individually. The amount of coupling agent was fixed at 2% for all formulations. The morphology, water absorption, thickness swelling, and mechanical properties of nanocomposites were evaluated as a function of nanoclay and glass fiber contents. The results indicated that both modulus and strength were improved when glass fibers were added to the composites system but impact strength and moisture absorption further decreased with the increase of glass fiber content. The morphology of the nanocomposites has been examined by using X‐ray diffraction. The morphological findings revealed that the nanocomposites formed were intercalated. The mechanical analysis showed that the biggest improvement of the tensile and flexural modulus and strengths can be achieved for the nanoclay loading at 4 per hundred compounds. However, further increasing of the loading of nanoclay resulted in a decrease of impact strength. Finally, it was found that addition of nanoclay reduced the water absorption and thickness swelling of the composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Development of poly(vinyl chloride)/wood composites. A literature review

Poly(vinyl chloride)/wood fiber (flour) composites are currently experiencing a dramatic increase in use. Most of them are used to produce window/door profiles, decking, railing, and siding by using conical counterrotating intermeshing twin‐screw extruders. Heat stabilizers, processing aids, impact modifiers, lubricants, and pigments are still important for PVC/wood composite formulations. Poly[methylene(polyphenyl isocyanate)] (PMPPIC), γ‐aminopropyltriethoxysilane, maleated polypropylene (MAPP), and copper metallic complex have proved to be effective coupling agents for this composite system. Mechanical properties of PVC/wood composites can be enhanced by combining wood with mica or glass fibers to form hybrid reinforcements. Ultraviolet light resistance and weathering dimensional stabilities of PVC/wood composites are superior to those of natural wood. Density reduction can be achieved through the microcellular foaming technique by using chemical blowing agents, such as azodicarbonamide and sodium bicarbonate, or physical blowing agents, such as carbon dioxide. J. Vinyl Addit. Technol. 10:59–69, 2004. © 2004 Society of Plastics Engineers.     

Injection‐molded short hemp fiber/glass fiber‐reinforced polypropylene hybrid composites—Mechanical,water absorption and thermal properties

Natural fiber‐based thermoplastic composites are generally lower in strength performance compared to thermoset composites. However, they have the advantage of design flexibility and recycling possibilities. Hybridization with small amounts of synthetic fibers makes these natural fiber composites more suitable for technical applications such as automotive interior parts. Hemp fiber is one of the important lignocellulosic bast fiber and has been used as reinforcement for industrial applications. This study focused on the performance of injection‐molded short hemp fiber and hemp/glass fiber hybrid polypropylene composites. Results showed that hybridization with glass fiber enhanced the performance properties. A value of 101 MPa for flexural strength and 5.5 GPa for the flexural modulus is achieved from a hybrid composite containing 25 wt % of hemp and 15 wt % of glass. Notched Izod impact strength of the hybrid composites exhibited great enhancement (34%). Analysis of fiber length distribution in the composite and fracture surface was performed to study the fiber breakage and fracture mechanism. Thermal properties and resistance to water absorption properties of the hemp fiber composites were improved by hybridization with glass fibers. Overall studies indicated that the short hemp/glass fiber hybrid polypropylene composites are promising candidates for structural applications where high stiffness and thermal resistance is required. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2432–2441, 2007     

Study on PVC composites containing Eugenia jambolana wood flour

This article describes the properties of composites using unplasticized PVC matrix and wood flour (obtained by crushing the bark of Eugenia jambolana) as filler. Composites were prepared by mixing PVC with varying amounts of wood flour (ranging from 10–40 phr; having particle sizes of 100–150 μm and <50μm) using two‐roll mill followed by compression molding. The effect of wood flour content and its particle size on the properties, i.e., mechanical, dynamic mechanical, and thermal was evaluated. Tensile strength, impact strength, and % elongation at break decreased with increasing amounts of wood flour. Stiffness of the composites (as determined by storage modulus) increased with increasing amounts of the filler. Modulus increased significantly when wood flour having particle size <50 μm was used. Morphological characterization (SEM) showed a uniform distribution of wood flour in the composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Biopolyamide hybrid composites for high performance applications

This study focuses on the performance characteristics of wood/short carbon fiber hybrid biopolyamide11 (PA11) composites. The composites were produced by melt‐compounding of the fibers with the polyamide via extrusion and injection molding. The results showed that mechanical properties, such as tensile and flexural strength and modulus of the wood fiber composites were significantly higher than the PA11 and hybridization with carbon fiber further enhanced the performance properties, as well as the thermal resistance of the composites. Compared to wood fiber composites (30% wood fiber), hybridization with carbon fiber (10% wood fiber and 20% carbon fiber) increased the tensile and flexural modulus by 168% and 142%, respectively. Izod impact strength of the hybrid composites exhibited a good improvement compared to wood fiber composites. Thermal properties and resistance to water absorption of the composites were improved by hybridization with carbon fiber. In overall, the study indicated that the developed hybrid composites are promising candidates for high performance applications, where high stiffness and thermal resistance are required. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43595.     

PP-g-MAH增容改性木粉/PP复合材料的性能研究

以马来酸酐接枝聚丙烯 (PP-g-MAH) 为相容剂,聚丙烯 (PP) 为基体,通过熔融共混法制备了木粉/PP复合材料。研究了 PP-g-MAH 用量对复合材料力学性能及吸水性能的影响; 采用扫描电镜 (SEM) 观察了复合体系的冲击断面形貌。结果表明: 当 PP-g-MAH 的质量分数为 4%时,可以提高添加 35 份木粉复合材料体系的拉伸强度及弯曲强度,比未添加相容剂的分别提高了 49.4%和 16%,而缺口冲击强度仅下降了 9%。SEM 观察证实: PP-g-MAH 的加入有利于提高木粉与 PP 基体的界面相互作用。从吸水率来看,木粉/PP 复合材料的吸水率保持在 0.22% 以下,远低于纯木材。     

改性椰壳粉／PVC复合材料结构和性能的研究

研究了偶联剂改性椰壳粉的种类及用量、椰壳粉的质量分数对椰壳粉／PVC复合材料性能的影响,并用扫描电镜（SEM）观察了拉伸断面。结果表明：硅烷偶联剂KH-550质量分数为2％时效果较好,拉伸强度提高了12．6％,冲击强度提高了30．6％;经过硅烷偶联剂KH-550改性,能增大椰壳粉填充质量分数,提高复合材料的维卡软化点温度,改善了椰壳粉纤维在PVC基体中分散性和相容性。     

Influence of various wood modifications on the properties of polyvinyl chloride/wood flour composites

Aminosilane, melamine and acetic anhydride treated wood flour were added to polyvinyl chloride (PVC) in order to process improved PVC/wood flour composites. The influence of wood treatment on water absorption and mechanical properties were evaluated. Treatments with amino-alkyl functional oligomeric siloxane and melamine in suitable concentration as well as acetylated wood flour composites showed decreased equilibrium moisture content and reduced speed of water absorption. Tensile strength, elongation at break and unnotched impact strength were considerably improved by the aminosilane treatments. The increase in strength and elongation was mainly influenced by the chemical structure and concentration of the used aminosilanes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

玻纤增强聚酰胺6/蒙脱土复合材料的制备及其力学性能研究

通过螺杆挤出法制备了玻璃纤维增强聚酰胺6/蒙脱土复合材料,利用电子万能试验机对复合材料的力学性能进行了测量,并对实验结果进行了分析。结果表明,随着玻璃纤维含量的增加,聚酰胺6/蒙脱土/玻璃纤维复合材料的拉伸强度和冲击强度相应地增大,且长度为12mm的玻璃纤维增强的复合材料比6mm玻璃纤维增强的复合材料高;当玻璃纤维含量为10%(质量分数,下同)时,12mm玻璃纤维增强的复合材料的拉伸强度和冲击强度分别比聚酰胺6/蒙脱土复合材料提高了17.4%和84.1%。     

Mechanical properties of extrusion‐foamed rigid PVC/wood‐flour composites

This study was conducted to characterize the mechanical properties of extrusion‐foamed neat rigid PVC and rigid PVC/wood‐flour composites by using endothermic and exothermic chemical foaming agents (CFAs). The specific elongation at break (ductility) of the samples was improved by foaming, while the opposite trend was observed for the tensile strength and modulus of the samples, regardless of the chemical foaming agent type. In addition, experimental results indicated that foaming reduced the Izod impact resistance of both neat rigid PVC and rigid PVC/wood‐flour composites but that this reduction was not statistically significant for the composites. A comparison between batch microcellular processing and extrusion foam processing was made, which demonstrated that foams with very fine cells (microcellular processed) exhibit better impact strength than foams with larger cells (extrusion processed with CFAs).     

剑麻纤维与玻纤混杂增强PVC复合材料的性能研究

本文介绍采用短麻纤维(SF)和短玻纤(GF)混杂增强PVC基体,测定了复合材料的弯曲强度、弯曲模量、无缺口冲击强度以及耐水浸泡性能,并探讨了这一复合材料在水浸泡前后的力学性能及其界面行为.结果表明,此种复合材料在弯曲模量和无缺口冲击强度上存在正的混杂效应,而弯曲强度存在负的混杂效应;经水浸泡后,复合材料的弯曲强度、弯曲摸量和冲击强度都有不同程度的下降,而对于纯PVC基体,水浸泡后的弯曲强度和弯曲模量反而有所提高,因此可以认为,水浸泡对纯PVC基体在弯曲性能方面无不良影响,水分主要对纤维与基体的界面产生不良作用,导致复合材料性能下降.     

聚丙烯/木粉复合材料的制备及其力学性能的研究

以聚丙烯为基体,木粉为填料,采用机械共混、二次挤出共混和注塑成型方法制备不同木粉含量的PP/木粉复合材料,并且测定了PP/木粉复合材料的力学性能。实验结果表明:随着木粉用量的增加,复合材料拉伸强度逐渐增大;木粉用量为60%时,复合材料拉伸强度达到最大值36.04 MPa;木粉用量为80%时,复合材料拉伸强度降低到34.60 MPa。木粉的含量由20%增加到80%,复合材料弹性模量由579.12 MPa增加到869.80MPa,断裂伸长率从18.92%降低到7.39%,冲击强度由9.33 kJ/m2降低到7.76 kJ/m2。这是因为PP/木粉复合材料体系中随着木粉含量的增加,木粉起到了应力集中的作用,使材料变脆,冲击强度降低。     

木粉对PVC木塑复合材料力学性能影响

采用电镜扫描观察了3种木粉的纤维细胞尺寸及其木粉微观形态。研究了木粉粒度、微观特性以及木粉添加量对了聚氯乙烯（PVC）木塑复合材料力学性能的影响。结果表明，木粉表面裸露的微细纤维增加和粒度减小，有助于提高木塑复合材料力学强度；加入少量木粉使木塑复合材料力学性能降低，但随着木粉添加量的增大，木塑复合材料的抗弯性能和拉伸强度上升；木塑复合材料的冲击强度随木粉含量增加而下降。     

Assessment of Glass/Drumstick Fruit Fiber (Moringa oleifera) Reinforced Epoxy Hybrid Composites

Glass fibers/drumstick fruit fibers (GF/DFF) reinforced with epoxy hybrid composites were fabricated using the rule of hybrid mixtures. Properties like impact strength, frictional coefficient, dielectric strength, and chemical resistance were studied. Treated and untreated DFF were reinforced along with GF to assess two different epoxy hybrid composites. The effect of alkali treatment on the above-mentioned properties was also studied. It is observed that the impact strength and frictional coefficient properties of the hybrid composites increased with increase in glass fiber content. Performance was elevated for alkali-treated DFF hybrid composites when compared with untreated DFF. Chemical resistance was significantly increased for all chemicals except carbon tetrachloride due to attack of chloride hydrocarbons on the cross-linking of the epoxy. Elimination of amorphous hemi-cellulose by alkali treatment improved the properties. Fiber-polymer interactions were studied by scanning electron microscopy on the cross-sections of fractured surfaces.     

Effect of macromolecular coupling agent on the property of PP/GF composites

Silane‐grafted polypropylene manufactured by a reactive grafting process was used as the coupling agent in polypropylene/glass‐fiber composites to improve the interaction of the interfacial regions. Polypropylene reinforced with 30% by weight of short glass fibers was injection‐molded and the mechanical behaviors were investigated. The results indicate that the mechanical properties (tensile strength, tensile modulus, flexural strength, flexural modulus, and Izod impact strength) of the composite increased remarkably as compared with the noncoupled glass fiber/polypropylene. SEM of the fracture surfaces of the coupled composites shows a good adhesion at the fiber/matrix interface: The fibers are coated with matrix polymer, and a matrix transition region exists near the fibers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1537–1542, 1999