On adhesion mechanisms and interfacial strength in acrylonitrile–butadiene–styrene/wood sawdust composites

Adhesion mechanisms and interfacial strengths of acrylonitrile–butadiene–styrene (ABS) copolymer/wood sawdust composites containing two different silane coupling agents [3-Methacryloxypropyl trimethoxysilane (KBM503) and N-2(aminoethyl)3-aminopropyl trimethoxysilane (KBM603)] were studied using the Fourier Transform Infrared (FTIR) technique and mechanical testing. The results suggested that increasing wood sawdust content tended to increase the modulus of the composites, but decreased the strength of the composites. Concentrations of 1.0 wt% KBM503 and 0.5 wt% KBM603 were recommended for the optimization of the mechanical properties of the composites, respectively. Up to the recommended dosages, KBM603 was more effective in terms of the improved interfacial strength of the composites. The adhesion mechanism performed by KBM503 involved dipole–dipole interaction at the ABS/sawdust interface, whereas that by KBM603 was associated with covalent chemical bonds at the interface. The improved interfacial strength of the composites was reduced by the increased amounts of wood sawdust particles.     

Mica reinforced nylon‐6: Effect of coupling agents on mechanical,thermal, and dielectric properties

The effects of applying titanate (TYZOR® TPT) and silane (DYNASYLAN VTMO) coupling agents to wet ground muscovite mica in nylon‐6 composites are described. Nylon‐6 composites of 5–40 wt % filler loadings were compounded using an APV Baker twin‐screw extruder. Mica (25 wt %) brought about an increase in the Young's modulus, flexural strength, and flexural modulus but did not produce significant variations in tensile and impact strength. Hence different coupling agents were employed. It was observed that titanate coupling agent improved the tensile strength and the Young's modulus of the composites much while the impact properties were enhanced by the silane coupling agent. An attempt was made to use ?‐caprolactum in improving the interfacial adhesion of the filler and the matrix. It was observed that ?‐caprolactum improved the flexural modulus of the composites most. The effect of coupling agents on the dielectric strength, heat distortion temperature, and morphology were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4074–4081, 2006     

Effects of silane and MAPE coupling agents on the properties and interfacial adhesion of wood-filled PVC/LDPE blend

Composite samples were prepared from Poly(vinyl chloride)/low-density polyethylene (PVC/LDPE) blend, compatibilized by PA20 (methyl methacrylate-co-butyl acrylate copolymer), and reinforced by different levels of rubber-wood sawdust. To improve the mechanical properties of the composites, Silane A-137 (Octyltriethoxy silane), Silane A-1100 (γ-aminopropyltriethoxy silane), or MAPE (maleic anhydride-grafted-polyethylene) were introduced. It was found that the additions of Silane A-137, Silane A-1100, and MAPE could improve tensile and impact properties of the composites, regardless of the sawdust contents. Physical or chemical interactions for all coupling agents with the wood-PVC/LDPE composites used were proposed in this work. Silane A-137 or MAPE tended to give better improvement in the mechanical properties of the composites than Silane A-1100, because of the presence of the nonpolar chain ends of Silane A-137 or MAPE molecules. Besides, the addition of either Silane A-137 and MAPE or Silane A-1100 and MAPE at different ratios into the wood-PVC/LDPE composites was also studied. The experimental results suggested that the optimum mechanical properties could be obtained using Silane A-137 : MAPE of 1% : 2% wt sawdust. The morphological and thermal properties of the composites were also examined using SEM and DMA techniques, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of sawdust surface treatment and compatibilizer addition on mechanical behavior,morphology, and moisture uptake of polypropylene/sawdust composites

Polypropylene/sawdust composites were investigated to assess the effect of sawdust surface treatment and compatibilizer addition on polymer/fiber adhesion. Two silane coupling agents were used for sawdust surface treatment: vinyl‐tris (2‐methoxyethoxy) silane and (3‐aminopropyl)triethoxysilane. Maleic anhydride grafted polypropylene was used as compatibilizer. Composites were prepared in a corotating twin‐screw extruder coupled to a Haake torque rheometer and submitted to tensile and bending tests as well as scanning electron microscopy (SEM). Moisture uptake tests were also performed. Results showed that incorporation of untreated sawdust to polypropylene (PP) caused reduction in composite tensile strength and increase in stiffness. When the only treatment used was surface modification with silane coupling agents, no significant changes were observed in mechanical properties. However, when compatibilizer was added to the composites, tensile strength was increased, and % elongation at break reduced, indicating improved system compatibility. The composite presenting the highest increase in tensile strength was that containing sawdust treated with amino silane in addition to the compatibilizer. SEM analyses corroborated the mechanical property results. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Effect of wood sawdust content on rheological and structural changes,and thermo‐mechanical properties of PVC/sawdust composites

The use of untreated sawdust as a filler in poly(vinyl chloride) (PVC) was examined—the effects of sawdust content on structural and thermal changes, and rheological and mechanical properties being of main interest. The results revealed that the torque and die entrance pressure drop values during mixing were independent of sawdust particles up to 23.1 wt%. The extrudate swell monotonically decreased up to 33.3 wt% sawdust content. Smooth wood‐like texture with controllable size of the extrudate could be obtained at a sawdust content greater than 33.3 wt%. Tensile, impact, flexural and hardness properties of the PVC/sawdust composites considerably decreased with up to 16.7 wt% sawdust content before leveling off for higher sawdust loadings. The composites having sawdust higher than 16.7 wt% showed a benefit of cost savings. The decreases in the mechanical properties of PVC with sawdust are explained in association with the presence of moisture, interfacial defects between fibre and polymer, and fibre dispersions in the PVC matrix. Thermal degradations of PVC in PVC/sawdust composites were evidenced by a decrease in decomposition temperature and an increase in polyene sequences, which were caused by Cl cleavage due to strong hydrogen bonds of fibre–PVC molecules. The maximum of tanδ transition and the glass transition temperature were found to improve with sawdust content as a result of re‐formation of hydrogen bonds between the macromolecules of the fibre and the polymer. The overall results in this work suggest that the properties of PVC/sawdust composites were strongly influenced by sawdust content up to 16.7 wt%. Beyond this value the effect of sawdust content on the properties was comparatively small. Copyright © 2003 Society of Chemical Industry     

Physicochemical characterization of the filler–matrix interface in elastomer‐encapsulated fly ash/polyester particulate composites

An attempt was made to improve the toughness of fly ash (FA)/general‐purpose unsaturated polyester resin (GPR) composites. Elastomer [styrene–butadiene rubber (SBR) or acrylic copolymer (AC)]‐encapsulated fillers (FA or CaCO₃) were made through the coagulation of the emulsified elastomer containing the filler with constant stirring. The elastomer‐encapsulated fillers were added to GPR at concentrations as high as 15 wt % to make FA/SBR or AC/GPR composites. The mechanical properties (i.e., the tensile strength, tensile modulus, tensile elongation, flexural strength, flexural modulus, impact strength, and hardness) of FA/GPR, FA/SBR/GPR, and FA/AC/GPR composites were studied. The tensile‐fractured surfaces of all the composites were studied with scanning electron microscopy. The thermal stability was studied with thermogravimetric analysis. An analysis of the results indicate that this modification technique is rather easy and more economical than the chemical modification of filler surfaces with functional silane coupling agents. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 171–184, 2005     

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。     

改性木纤维/PVC复合材料界面及性能的研究

比较了硅烷偶联剂处理、氢氧化钠溶液浸泡与硅烷偶联剂双重处理,接枝改性等3种木纤维表面处理方法对木纤维/PVC复合材料界面及性能的影响,通过扫描电镜照片发现接枝改性木纤维在PVC基体中分散更均匀,与PVC界面相容性好.接枝改性木纤维/PVC复合材料的拉伸强度、冲击强度、断裂伸长率等力学性能有明显提高.最后分析了木纤维接枝改性处理时引发剂用量对复合材料力学性能的影响.     

聚己内酯/聚乳酸/竹纤维复合材料制备及性能

以聚己内酯（PCL）和聚乳酸（PLA）共混物为基材,竹纤维（BF）作为增强材料,硅烷偶联剂为改性剂,通过模压成型制备了PCL/PLA/BF复合材料。研究了PCL和PLA质量比、BF质量分数、硅烷偶联剂用量以及模压温度对复合材料性能影响。结果表明,适宜的PCL/PLA质量比为1∶1,BF质量分数为40 %时BF/PCL/PLA复合材料的冲击强度、拉伸强度和断裂伸长率分别达到最大值11.26 kJ/m2,12.68 MPa和5.2 %;硅烷偶联剂用量为1 %时复合材料的冲击强度、拉伸强度和断裂伸长率分别达到最大值15.11 kJ/m2、13.15 MPa和5.8 %;模压温度为150 ℃时,复合材料的冲击强度、拉伸强度和断裂伸长率分别达到最大值14.51 kJ/m2、13.75 MPa和5.8 %。     

Effect of moisture content on mechanical properties,thermal and structural stability and extrudate texture of poly(vinyl chloride)/wood sawdust composites

Mechanical properties and thermal and structural changes of poly(vinyl chloride) (PVC)/wood sawdust composites were assessed with respect to the effect of moisture content, varying from 0.33 to 3.00 % by weight in the composite, for three different wood sawdust contents. The swell ratio and texture characteristics of the composite extrudates were also evaluated. Unique explanations were given to describe changes in the composite properties in terms of molecular interactions between PVC, cellulosic sawdust and moisture, such as dipole–dipole interactions, interfacial defects and bonding, fibre swelling, and moisture evaporation. The results suggest that at low moisture content the tensile modulus decreased and elongation at break of the composites increased with moisture content, the effect being reversed for high moisture content. Tensile strength decreased with increasing moisture content up to 1–2 %, and then unexpectedly increased at higher moisture contents. The effect of moisture content on flexural properties of the composite was similar to that on tensile properties. Impact strength of the composites was considerably improved with moisture content at low sawdust contents (16.7 wt%), and was independent of the moisture content at higher sawdust contents (28.6 and 37.5 wt%). A decrease in decomposition temperature with an increase in polyene content was evidenced with increasing moisture content, while the glass transition temperature did not change with varying moisture content. The extrudate swell ratio increased with the shear rate but remained unaffected by moisture content. The bubbling and peeling‐off in the composite extrudate occurred as a result of the evaporation of water molecules and the application of a high shear rate. Copyright © 2004 Society of Chemical Industry     

Effects of acrylic‐based processing aids on processibility,rheology, thermal and structural stability,and mechanical properties of PVC/wood–sawdust composites

Methyl methacrylate and ethylacrylate (MMA‐co‐EA) and methyl methacrylate and butylacrylate (MMA‐co‐BA) copolymeric processing aids were introduced into poly(vinyl chloride) (PVC)/33.3 wt % wood–sawdust composites containing 0.6 and 2.4 phr of calcium stearate lubricant. The properties of the composites were monitored in terms of processibility, rheology, thermal and structural stability, and mechanical properties. It was found that the mixing torque, wall shear stress, and extrudate swell ratio increased with increasing processing aid content because of increased PVC entanglement. MMA‐co‐BA (PA20) was found to be more effective than MMA‐co‐EA (K120 and K130), this being associated with the flexibility of the processing aids, and the dipole–dipole interactions between sawdust particles and polymeric processing aids. The sharkskin characteristic of the composite extrudate at high extrusion rate was moderated by the presence of processing aids. Adding the acrylic‐based processing aids and lubricant into PVC/sawdust composites improved the thermal and structural stability of the composites, which were evidenced by an increase in glass transition and decomposition temperatures and a decrease in polyene sequences, respectively. The changes in the mechanical properties of the composites involved a composite homogeneity, which was varied by degree of entanglement and the presence of wood sawdust, and un‐reacted processing aids left in the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 782–790, 2004     

Effects of compatibilizer type and rubber‐wood sawdust content on the mechanical,morphological, and thermal properties of PVC/LDPE blend

This article aimed to investigate the mechanical, morphological and thermal properties of PVC/LDPE blend with and without the addition of compatibilizers. The effects of LDPE content, compatibilizer type and rubber‐wood sawdust loading on the properties of the blend were evaluated. The experimental results suggested that as the LDPE content was increased the mechanical properties of PVC‐LDPE blend progressively decreased due to poor interfacial adhesion. The continuity and compatibility between PVC and LDPE phases could be improved through three different types of compatibilizers which included chlorinated polyethylene (CPE) poly(methyl‐methacrylate‐co‐butyl acrylate) (PA20) and poly(ethylene‐co‐methacrylate) (Elvaloy). The PA20 was found to be the most suitable compatibilizer for the blend. A radical transfer reaction was proposed in this work to explain the structure and thermal changes of the PVC in PVC‐LDPE blend. The decomposition temperature of PVC in the blend decreased with the loading of the PA20 and the wood sawdust. As the sawdust content was increased the tensile and flexural moduli increased with considerable decreased in the tensile, flexural and impact strength, a slight improvement being achieved if the PA20 was incorporated in the composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 598–606, 2006     

偶联剂对聚乳酸/蔗渣纤维复合材料力学性能的影响

采用了4种硅烷偶联剂处理甘蔗渣,研究了偶联剂品种和含量对聚乳酸/甘蔗渣复合材料力学性能的影响,并运用扫描电子显微镜对复合材料的冲击断面进行了观察。结果表明,甘蔗渣经过硅烷偶联剂表面处理后,聚乳酸/甘蔗渣复合材料的力学性能较未处理体系有不同程度的提升,其中Z-6032的处理效果最佳。聚乳酸/甘蔗渣复合材料的力学强度受甘蔗渣粒径和含量的影响;甘蔗渣的粒径越小,复合材料的冲击强度越大;随着甘蔗渣含量的增大,复合材料的冲击强度和拉伸强度均呈下降趋势。     

空心玻璃微球填充改性PVC的研究

采用共混法合成了空心玻璃微球／聚氯乙烯（PVC）复合材料,空心玻璃微球使用前先用硅烷偶联剂KH-550进行了表面改性。通过高倍光学显微镜、红外分析仪、电子拉力机、邵氏硬度检测仪等手段研究了空心玻璃微球的含量对PVC抗拉强度,冲击强度和硬度等性能影响。结果表明：随着玻璃微球含量的逐渐增加,PVC复合材料的拉伸强度先增加后...     

Effect of surface coverage of silane treated CaCO3 on the tensile properties of polypropylene composites

Polypropylene (PP) composites were prepared with a constant volume fraction of a CaCO₃ filler, which was treated with eight trialkoxy functional silane coupling agents and the routinely used stearic acid, as comparison, The tensile properties of the composites were determined as a function of surface coverage and the chemical composition of the coupling agent. Significant differences were detected in the effect of the silane coupling agents on the tensile properties of the composites studied. They could be classified into groups of reactive, nonreactive and inactive compounds, in accordance with an earlier study. Moreover, tensile properties proved to be very sensitive to surface treatment. Reactive coupling leads to a maximum in tensile strength, while the use of nonreactive agents decreases strength rapidly with increasing surface coverage. The rate of strength decrease slows down above the concentration necessary for the formation of a monolayer coverage. Treatment influences deformability accordingly, it decreases on reactive coupling, while agents with a surfactant effect increase elongation. Amino functional silanes show a strong reactive coupling effect. A trialkoxy derivative of stearic acid, (3-stearyloxy-propyl-triethoxy-silane), synthesized the first time in our laboratory, has an outstanding surfactant effect; its use increases both the elongation and the tensile strength of the composites. Both characteristics exceed the corresponding properties of the reference composite containing the filler treated with stearic acid.     

Flame retardancy,antifungal efficacies,and physical–mechanical properties for wood/polymer composites containing zinc borate

This work aimed to examine flame retardancy, antifungal performance and physical–mechanical properties for silane‐treated wood–polymer composites (WPCs) containing zinc borate (ZnB). ZnB with content from 0.0 to 7.0 wt% was added to WPCs, and silane‐treated wood contents were varied. The polymers used were poly(vinyl chloride) (PVC) and high‐density polyethylene (HDPE). The decay test was performed according to the European standard EN 113. Loweporus sp., a white‐rot fungus, was used for antifungal performance evaluation. Antifungal performance was observed to decrease with wood content. Incorporation of ZnB at 1.0 wt% significantly increased the antifungal performance of WPCs. ZnB content of greater than 1.0 wt% lowered the antifungal properties of WPCs. The results suggested that the wood/PVC composite exhibited better antifungal performance than the wood/HDPE composite. The addition of wood flour to PVC and HDPE decreased flame retardancy, whereas the incorporation of ZnB retained the flame retardancy. ZnB was found to be more appropriate for wood/PVC than wood/HDPE as a result of hydrogen chloride generated from the dehydrochlorination reaction of PVC. The results indicated that the addition of ZnB did not affect the physical‐mechanical properties of neat polymers and the composites. Copyright © 2016 John Wiley & Sons, Ltd.     

PVC／蒙脱土复合材料的制备与结构研究

采用钠基蒙脱土及经有机化处理后的蒙脱土分别通过纳米粒子直接填充分散法和熔融插层法与PVC混合制备PVC/蒙脱土纳米复合材料。对有机蒙脱土的结构进行了表征；对上述两类纳米复合材料的结构及力学性能进行了研究。此外，考察了采用硅烷偶联剂KH570处理钠基蒙脱土后与PVC熔融混合制备的纳米复合材料的力学性能。结果表明，经硅烷偶联剂处理后，纳米复合材料的拉伸强度和冲击强度均有明显的提高。     

不饱和聚酯树脂/大麻纤维复合材料性能的研究

采用模压工艺制备了不饱和聚酯(UP)树脂/大麻纤维复合材料,研究了大麻纤维加入量及纤维的碱处理、乙酰化处理及偶联剂处理对复合材料力学性能的影响;采用傅立叶变换红外光谱仪对复合材料的结构进行了表征和分析。结果表明,随着大麻纤维含量的增加,UP树脂/大麻纤维复合材料的拉伸弹性模量逐渐增加,拉伸强度、弯曲强度、弯曲弹性模量及冲击强度等均先降低而后逐渐增大;偶联剂处理对复合材料力学性能的改善效果最好;偶联剂与纤维之间发生了酯化反应。     

Mechanical properties of wood flake–polyethylene composites. II. Interface modification

This article discusses the methods of interface modification of composites based on raw wood flakes and high‐density polyethylene (HDPE) and the effects of these modifications on composite properties. An HDPE matrix was modified by a reaction with maleic anhydride (MA) in a twin‐screw extruder and then compounded with wood flakes to produce wood–polyethylene composites. Wood flakes were modified by a reaction with a silane coupling agent in an aqueous medium before being compounded with HDPE to produce silane‐modified WPCs. Differential scanning calorimetry and Fourier transform infrared spectroscopy data provide evidence for the existence of a polyethylene (PE)–silane‐grafted wood structure, which acts as a compatibilizer for wood flakes and PE. The results of MA‐modified composites indicate that some maleated HDPE is reacting with wood through esterification to form a compatibilizer for wood flakes and HDPE. Significant improvements in tensile strength, ductility, and Izod impact strength were obtained. Scanning electron micrographs provide evidence for strong interactions between the wood flakes and the matrix agent. The results indicate that 1–2 wt % MA modification on HDPE and 1–3 wt % silane treatment on wood flakes provide WPCs with the optimum properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2505–2521, 2002     

聚氯乙烯/纳米氧化铝复合材料的制备与性能

利用硅烷偶联剂（KH 550）对纳米氧化铝进行有机化处理,并通过熔融共混制备了聚氯乙烯/纳米氧化铝复合材料。通过红外分析对纳米氧化铝进行了表征,采用扫描电子显微镜观察了纳米氧化铝在聚氯乙烯树脂中的分散状况,并对复合材料的热性能和力学性能进行了研究。结果表明,经过表面改性的纳米氧化铝粒子在PVC基体中分布均匀;加入纳米氧化铝改善了复合材料的热性能和力学性能;当纳米氧化铝含量为3.0 %（质量分数,下同）时,复合材料的拉伸强度和冲击强度相对于纯聚氯乙烯材料分别提高了16.25 %和20.27 %。