几种木质纤维在PE基木塑复合材料中的对比研究

PE基木塑复合材料是目前国内生产的木塑复合材料的主要品种之一,该类材料目前所采用的主要木质纤维是稻糠和木粉.文章对比了稻糠、松木粉、竹粉、麦秸纤维、稻草纤维等几种木质纤维的干燥特性及其在PE基木塑复合材料中的应用效果.研究表明,由5种不同的木质纤维制备的PE基木塑复合材料的物理机械性能十分接近,这为进一步提高我国废弃植物纤维的综合利用水平、丰富PE基木塑复合材料的品种提供了参考依据.     

木质纤维填料对PE–HD基木塑复合材料热性能的影响

分别以木粉、竹粉、稻壳粉三种木质纤维为填料,高密度聚乙烯(PE–HD)为基体,采用模压成型法制备木塑复合材料,对复合材料的热膨胀性能和热失重特性进行了研究。结果表明,三种木质纤维填充PE–HD复合材料的线性热膨胀系数顺序为:PE–HD/木粉复合材料PE–HD/竹粉复合材料PE–HD/稻壳粉复合材料;PE–HD/木粉复合材料的线性热膨胀系数随着木粉含量的增加和木粉粒径的减小而减小,木粉质量分数为65%、粒径为150μm时,复合材料的线性热膨胀系数最小。PE–HD基木塑复合材料的热分解过程分为两个阶段,第一阶段主要为木质纤维分解阶段,第二阶段主要是PE–HD分解阶段;PE–HD/木粉复合材料起始失重温度高于竹粉和稻壳粉填充的复合材料;且PE–HD/木粉复合材料中木粉含量越高,第一阶段分解速率及失重量越大;木粉粒径越小,复合材料起始分解温度越低。     

不同变量因子对木塑复合材料的力学性能研究

以木质纤维为原料,聚丙烯(PP)树脂和聚乙烯(PE)树脂为基体,采用人造板"热进冷出"平压工艺,制备出多种木塑复合材料,并对该材料进行物理力学性能分析,旨在寻求最佳组分配比。研究表明:在35%~40%的范围内,随着木纤维含量的增加,静曲强度、弹性模量上升,在40%~50%内下降,PP基木塑复合材料在木纤维含量在35%~40%内,冲击强度上升,在40%~50%内下降,而PE基木塑复合材料在木纤维含量在35%~50%内缓慢递减。结果表示木塑比为40:60,基体为PE,偶联剂是KH560时,木塑复合材料的综合性能最好。     

木塑复合材料无卤阻燃的研究进展

木塑复合材料是由热塑性高分子材料与木质纤维复合制备而成的新型环保材料。综述了其阻燃的机制,介绍了PE、PP、PVC基等木塑复合材料中不同阻燃剂体系的无卤阻燃现状,并展望了木塑复合材料无卤阻燃的发展趋势。     

HDPE/稻糠复合材料性能研究

研究了稻糠表面处理方法、稻糠含量、HDPE回收料用量等对HDPE／稻糠复合材料物理性能的影响规律。结果表明,采用常规偶联剂处理稻糠时,对HDPE／稻糠复合材料的改性效果较差;在制备HDPE木塑复合材料时,稻糠与松木粉的应用效果相近;同时,应根据材料的使用性能要求,严格控制稻糠用量和HDPE回收料的用量。     

基于木塑复合材料的现代家居造型设计与工艺分析

研究了聚乙烯基木塑复合材料的吸水性、热工性能和力学性能。结果表明,相较于木质材料,木塑复合材料的吸水性极低(15%),失重的温度区间大、热稳定性能好和其抗变形能力可控,硬度大,具有良好的抗磨性能和强冲击性能。因此,木塑复合材料能够满足现代家居设计的要求。     

两种不同基体木塑复合材料的制备及性能研究

以稻糠代替木粉,分别制备了高密度聚乙烯(HDPE)基体和聚甲醛(POM)基体木塑复合材料。结果表明稻糠含量小于50%时,这两种木塑复合材料均具有良好的加工流动性;稻糠含量从0增加到50%,拉伸强度和冲击强度下降,热变形温度提高;稻糠含量40%时,木塑复合材料韧性相对于单纯树脂下降最小;稻糠含量在40%时,耐热性能改善效果最为明显。综合各因素对木塑复合材料性能的影响,稻糠填充量选在40%较合适。POM基体木塑复合材料在拉伸性能、弯曲性能和耐热性能方面优于HDPE基体木塑复合材料,但在无缺口冲击性能方面HDPE基体木塑复合材料优于POM基体木塑复合材料。     

建筑模板用聚乙烯基木塑复合材料的制备及其性能

以聚乙烯为基体,分别与木片、木质纤维、木质纤维粉制备了聚乙烯基木塑复合材料。分别利用液体石蜡、甲基丙烯酸甲酯、NaOH乙醇溶液、邻苯二甲酸酐乙醇溶液、H2O2乙醇溶液对木片、木质纤维、木质纤维粉进行预处理,并考察了相应木塑复合材料的拉伸强度和胶合强度。结果表明:邻苯二甲酸酐乙醇溶液和H2O2乙醇溶液对木材表面改性处理效果较为明显,相应的木塑复合材料的拉伸强度和胶合强度也更高;与木质纤维粉和木片相比,木质纤维与聚乙烯具有更好的相容性;当木质纤维质量分数为30%时,采用H2O2乙醇溶液预处理后,木塑复合材料的拉伸强度为28.2 MPa,胶合强度为8.68 MPa;利用邻苯二甲酸酐乙醇溶液预处理后,木塑复合材料的拉伸强度为26.7 MPa,胶合强度为7.92 MPa。     

PE基木塑复合材料动态弹性模量优势因素分析

以聚乙烯（PE）基木塑复合材料为研究对象,利用弯曲振动法和纵向振动法对PE基木塑复合材料进行了动态弹性模量的检测。研究了木塑比与偶联剂等主要因素对动态弹性模量的影响规律。对比了加工因素对密度和动态弹性模量影响的关系曲线,并进行了加工因素和密度对动态弹性模量的相关性分析。结果表明,木塑比是影响动态弹性模量的首要因素;在木塑比55：45~70：30的范围内,PE基木塑复合材料的动态弹性模量与木塑比成正比关系;偶联剂含量为2 %~5 %时,随着偶联剂含量的增加,PE基木塑复合材料的动态弹性模量也随之升高;利用成型温度、偶联剂含量和密度对PE基木塑复合材料的动态弹性模量进行预测是可行的。     

不同树脂基木塑复合材料的性能对比

由于木塑复合材料中所用的木质纤维填料一般只能承受200℃加工温度,因此,木塑复合材料一般采用聚乙烯、聚丙烯、聚氯乙烯等加工温度较低的热塑性树脂。基体树脂类型不同时,木塑复合材料的性能差异较大。本文初步研究了基体树脂类型及木质纤维类型对木塑复合材料制品性能的影响规律,这对人们根据制品的应用领域舍理地选择基体树脂和木质纤维具有一定的参考价值。     

Mechanical properties of composites from sawdust and recycled plastics

Mechanical properties of wood plastic composites (WPCs) manufactured from sawdust and virgin and/or recycled plastics, namely high density polyethylene (HDPE) and polypropylene (PP), were studied. Sawdust was prepared from beech industrial sawdust by screening to the desired particle size and was mixed with different virgin or recycled plastics at 50% by weight fiber loading. The mixed materials were then compression molded into panels. Flexural and tensile properties and impact strength of the manufactured WPCs were determined according to the relevant standard specifications. Although composites containing PP (virgin and recycled) exhibited higher stiffness and strength than those made from HDPE (virgin and recycled), they had lower unnotched impact strengths. Mechanical properties of specimens containing recycled plastics (HDPE and PP) were statistically similar and comparable to those of composites made from virgin plastics. This was considered as a possibility to expand the use of recycled plastics in the manufacture of WPCs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3641–3645, 2006     

Effect of Coupling Agent Concentration,Fiber Content,and Size on Mechanical Properties of Wood/HDPE Composites

In this study, the influence of coupling agent concentration (0 and 3 wt%), wood fiber content (50, 60, 70, and 80 wt%), and size (40–60, 80–100, and 160–180 mesh) on the mechanical properties of wood/high-density-polyethylene (HDPE) composites (WPCs) was investigated. WPC samples were prepared with poplar wood-flour, HDPE, and polyethylene maleic anhydride copolymer (MAPE) as coupling agent. It was found that the tensile properties and the flexural properties of the composites were improved by the addition of 3 wt% MAPE, and the improved interfacial adhesion was well confirmed by SEM micrographs. It was also observed that the best mechanical properties of wood/HDPE composites can be reached with larger particle size in the range studied, while too-small particle size was adverse for the mechanical properties of wood/HDPE composites. Moreover, the tensile modulus, tensile strength, and flexural strength of WPCs decreased with the increase in fiber content from 50 to 80 wt%; the flexural modulus of WPCs increased with the increase in fiber content from 50 to 70 wt% and then decreased as the fiber content reached 80 wt%. The variances in property performance are helpful for the end-user to choose an appropriate coupling agent (MAPE) concentration, wood fiber content, and particle size based on performance needs and cost considerations.     

短纤维增强HDPE泡沫复合材料的研究

报道了以尼龙－６短纤维增强ＨＤＰＥ结构泡沫材料以及木粉填充ＨＤＰＥ结构泡沫材料的力学性能，探讨了粘合剂对尼龙－６短纤维和ＨＤＰＥ泡沫基材的粘合使用，并分析了不同加工助剂对木粉填充ＨＤＰＥ发泡体系加工性能和外观的影响。     

Preparation and characterization of LDPE and PP—Wood fiber composites

Natural fiber reinforced composites is an emerging area in polymer science. These natural fibers are low cost fibers with low density and high specific properties. These are biodegradable and nonabrasive. The natural fiber composites offer specific properties comparable to those of conventional fiber composites. However, in development of these composites, the incompatibility of the fibers and poor resistance to moisture often reduce the potential of natural fibers, and these draw backs become critical issue. Wood‐plastic composites (WPC) are a relatively new class of materials and one of the fastest growing sectors in the wood composites industry. Composites of wood in a thermoplastic matrix (wood–plastic composites) are considered a low maintenance solution to using wood in outdoor applications. WPCs are normally made from a mixture of wood fiber, thermoplastic, and small amounts of process and property modifiers through an extrusion process. In this study, Wood–plastic composites (WPC) are produce by adding a maleic anhydride modified low density polyethylene coupling agent to improve interfacial adhesion between the wood fiber and the plastic. Mixing is done with twin screw extruder. Subsequently, tensile strength, the modulus of elasticity, % elongation, hardness, Izod impact strength, melt flow index (MFI), and heat deflection temperature (HDT) are determined. Thermal transition temperatures and microstructure are determined with DSC and SEM, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of straw/magnesium cement composites with high-strength and fire-retardant

To fully exploit the abundant bioresource crop straw, a straw-based composite with excellent fire retardant, high strength and dimensional stability was successfully prepared for use in building applications. The subject composite was composed of rice straw/magnesium cement (SMC) adhesive, with glass fiber as a reinforcement agent. The mechanical strength, dimensional stability, flame retardant, smoke suppression, and thermal stability of the material were used to evaluate its performance as a potential construction material. The effect of the addition of glass fiber and the pavement structure of straw and glass fiber were also characterized. The experimental results showed that the mechanical strength and rigidity of SMC composite were increased by the addition of 9% glass fiber to the total mass of the filler. Glass fibers reinforced and reduced the volume of the filler, while increasing the dimensional stability of the composites. The strength of the mixed structural composites was higher than layered structural composites, which is benefits the preparation of the composites. Compared to other straw/cement composites, glass-fiber reinforced SMC composites exhibited better strength, dimensional stability, flame retardant, smoke suppression and thermal stability. These superb properties make these novel composites an ideal candidate for use in the field of interior decoration, particularly in public venues.     

Novel regenerated cellulose fibers from rice straw

Regenerated cellulose fibers from rice straws with a diameter of 10 to 25 μm and initial modulus of 11 to 13 GPa were prepared by wet spinning in rice straw/N‐methylmorpholine‐N‐oxide (MMNO) solution. X‐ray diffraction analysis indicates that the rice straw regenerated fibers are classified as cellulose (II). This observation indicates a potential utility of rice straw as an alternative to wood pulp as a cellulose‐based fiber material. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1705–1708, 2001     

Effects of rice straw fiber morphology and content on the mechanical and thermal properties of rice straw fiber‐high density polyethylene composites

Rice straw fiber‐high density polyethylene (HDPE) composites were prepared to investigate the effects of rice straw fiber morphology (rice straw refined fiber, rice straw pellet, rice straw strand), fiber content (20 and 40 wt %), and maleic anhydride polyethylene (MAPE) concentration (5 wt %) on the mechanical and thermal properties of the rice straw fiber‐HDPE composites in this study. Rice straw refined fiber exhibited more variability in length and width, and have a higher aspect ratio of 16.3. Compared to the composites filled of rice straw pellet, the composites made of the refined fiber and strand had a slightly higher tensile strength and lower tensile elongation at break. The tensile and flexural strength of the composites increased slightly with increasing rice straw fiber content up to 40 wt %, while the tensile elongation at break decreased. With addition MAPE, the composites filled with 20 wt % rice straw fiber showed an increase in tensile, flexural and impact strength and a decrease in tensile elongation at break. Differential scanning calorimetry showed that the fiber addition and morphology had no appreciable effect on the crystallization temperature of the composites but decreased the crystallinity. The scanning electron microscopy observation on the fracture surface of the composites indicated that introduction of MAPE to the system resulted in promotion in fiber dispersion, and an increase in interfacial bonding strength. Fiber breakage occurred significantly in the composites filled with refined fiber and strand after extruding and injection processing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of temperature on hygroscopic thickness swelling rate of composites from lignocellolusic fillers and HDPE

Effect of temperature on hygroscopic thickness swelling rate of lignocellolusic fillers/HDPE (high density polyethylene) composites was investigated. The composites were manufactured using a dry blend/hot press method. In this method, powder of plastic and dried powder of lignocellolusic material were mixed in high‐speed mixer and then the mixed powder were pressed at 190°C. Lignocellolusic fillers/HDPE composites panels were made from virgin and recycled HDPE (as plastic) and wood sawdust and flour of rice hull (as filler) at 60% by weight filler loadings. Nominal density and dimensions of the panels were 1 g/cm³ and 35 × 35 × 1 cm³, respectively. Thickness swelling rate of manufactured wood plastic composites (WPCs) were evaluated by immersing them in water at 20, 40, and 60°C for reaching a certain value where no more thickness was swelled. A swelling model developed by Shi and Gardner [Compos. A, 37 , 1276 (2006)] was used to study the thickness swelling process of WPCs, from which the parameter, swelling rate parameter, can be used to quantify the swelling rate. The results indicated that temperature has a significant effect on the swelling rate. The swelling rate increased as the temperature increased. The swelling model provided a good predictor of the hygroscopic swelling process of WPCs immersed in water at various temperatures. From the activation energy values calculated from the Arrhenius plots, the temperature had less effect on the thickness swelling rate for the composites including wood sawdust compared with the rice hull as filler and the composites including recycled compared with the virgin HDPE as plastic. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers