SEBS-g-MAH和原位接枝MAH对木粉/废旧塑料混合物复合材料力学性能的影响研究

由聚丙烯（PP）、高密度聚乙烯（HDPE）和聚苯乙烯（PS）组成的混合废旧塑料与木粉经高速混合机混合后,采用双螺杆/单螺杆串联挤出机组制备了木粉/混合废旧塑料复合材料。探讨了马来酸酐接枝苯乙烯-乙烯/丁烯-苯乙烯嵌段共聚物（SEBS-g-MAH）和原位接枝马来酸酐（MAH）对木粉/混合废旧塑料复合材料力学性能的影响。结果表明,与使用MAH和DCP的原位反应共混相比,SEBS-g-MAH显著提高了复合材料的抗冲击性能,但对拉伸和弯曲性能的改善不如原位反应共混显著。总的来说,混合废旧塑料制备的复合材料的力学性能要低于纯塑料混合物制备的复合材料,尤其是拉伸断裂伸长率。微观形态研究表明,添加SEBS-g-MAH和原位接枝MAH均可提高木粉与塑料混合物之间的界面相容性,但与添加SEBS-g-MAH相比,原位接枝MAH能更好的改善PP、HDPE、PS与木粉之间的界面结合。原位接枝MAH可被看作是一种改善木粉与塑料混合物间界面相容性的有效途径。此外,采用动态力学分析（DMA）进一步表征了复合材料的储能模量和阻尼因子。     

三种塑料与木纤维复合性能的研究

选用线性低密度聚乙烯(LLDPE)、聚丙烯(PP)、聚苯乙烯(PS)为原料,以2种比率与木纤维复合,用热压法制备了3种木塑复合材料,分析了塑料种类对复合材料的物理力学性能的影响.结果表明,LLDPE与木纤维的复合性能最好,其复合材料的抗冲击性好,但弯曲强度和弹性模量最低;PS与木纤维的复合性最差,其复合材料抗冲击性很差,但弯曲强度和弯曲弹性模量高;木纤维与PP复合材料的综合性能最佳.由此提出用LLDPE与PS共混改性制造木/塑复合材料的设想.     

桐马酸酐甲酯改性杨木纤维增强环氧树脂复合材料性能研究

以桐马酸酐甲酯改性杨木纤维(MEMA-PWF)为增强体、双酚A缩水甘油醚型环氧树脂(E51)/甲基四氢邻苯二甲酸酐(MeTHPA)为基体树脂,经热压成型制备杨木纤维增强环氧树脂复合材料.通过接触角测量、扫描电镜(SEM)分析表征了复合材料表面及断裂面结构形貌,并测试了复合材料的冲击强度、弯曲强度.实验结果表明,改性后的杨木纤维表面疏水性及其与环氧树脂基体界面相容性得到明显提高;以MEMA-PWF/环氧树脂体系制备的复合材料力学性能提高,冲击强度、弯曲强度分别达到7.95 kJ/m2、55.42 MPa,并具有较好的疏水性.     

芦苇纤维用量对芦苇纤维/聚乙烯(PE)复合材料力学性能的影响

以芦苇纤维作为增强体，以高密度聚乙烯(HDPE)和线性低密度聚乙烯(LLDPE)共混物作为基体，制备芦苇纤维/聚乙烯(PE)复合材料。探讨了芦苇纤维用量对复合材料力学性能以及微观结构的影响。结果表明：当LLDPE和HDPE的质量比为30∶70、芦苇纤维用量为30%时，所得复合材料的综合性能较好；静曲强度达到最高值25.9 MPa,较PE共混材料提升了12.1%;拉伸强度达到最高值22.3 MPa,较PE共混材料提升了14.4%;冲击强度为6.7 KJ·m^-2。     

增容处理对废PE木塑复合材料性能和结构的影响

采用熔融共混法制备二次植物纤维／废渣粒子混杂增强废地膜木塑复合材料,考察了增容剂马来酸酐接枝聚乙烯（PE—g—MA）对废地膜混杂木塑复合材料性能和结构的影响。研究表明,PE—g-MA是共混体系的良增容剂,PE—g—MA的加入显著提高了共混体系的力学性能。ATR和DSC分析表明,PE—g—MA的加入有效改善了混杂共混物的界面粘着力,提高了基体的结晶程度。     

针状木纤维/HDPE复合材料的力学性能

采用一步法连续挤出技术将杨木针状纤维与高密度聚乙烯(HDPE)进行熔融复合制备木塑复合材料(NF-WPC).用正交试验法分析纤维尺寸、纤维添加量、偶联剂含量和润滑剂含量4个因子对NF-WPC力学性能影响的显著性;用扫描电子显微镜观察分析NF-WPC中木纤维与HDPE的界面结合状况;提出优化的工艺配方并与相同木材含量的木粉/HDPE复合材料进行对比研究.结果表明:针状木纤维的含量对NF_WPC冲击强度影响显著,对弯曲性能和拉伸性能的影响高度显著;偶联剂马来酸酐接枝聚乙烯(MAPE)的添加量对NF_WPC的拉伸强度、断裂伸长率和冲击强度影响显著;在本文的试验范围内,木纤维尺寸和润滑剂石蜡的含量对NF-WPC力学性能的影响不显著.确定的优化工艺配方为:木纤维长度为3～4mm、长径比为8～11,木纤维含量60%,MAPE含量4%,石蜡含量0.3%;采用优化工艺制备的NF_WPC的弯曲强度、弯曲模量、拉伸强度、拉伸模量和冲击强度分别为58.7 MPa、3.0 GPa、39.6 MPa、4.0 GPa和12.7 kJ·m-2.除冲击韧性略低外,用优化工艺配方制备的NF_WPC其他力学性能均高于用同比例木粉制备的木塑复合材料.     

改性木质素增强木塑复合材料及其性能

以碱木质素为研究对象,通过对其进行羟甲基化改性,再将改性后的碱木质素、桉木粉、高密度聚乙烯以及助剂,通过熔融混炼、挤出造粒、热压成型的方法制备木塑复合材料(WPC)。利用红外光谱研究了木质素改性前后化学基团的变化,并对改性木质素制备的木塑复合材料力学性能、吸水性能、动态热机械性能进行测定分析。结果表明:羟甲基化改性能够使羟甲基接入到苯环酚羟基的邻位或对位上,改性木质素制备的木塑复合材料试件的静曲强度、拉伸强度、冲击强度都得到了明显的提高,最高静曲强度提高了37.68%,拉伸强度提高了51.50%,冲击强度提高了40.04%。热分析表明含木质素的木塑复合材料体系各组分之间具有较好的相容性,能够形成均一的体系。通过断面微观形貌的观察可知,改性木质素制备的木塑复合材料断面更为密实均匀。腐朽试验证明,改性木质素制备的木塑复合材料体现出了更好的耐腐性。综合考虑多项指标,在反应温度为90℃、木质素与甲醛质量比为3∶1和6∶1的改性条件下,改性木质素制备的木塑复合材料性能较佳。     

纳米Al_2O_3/PP/木纤维复合材料力学性能研究

通过偶联剂KH550改性纳米Al_2O_3后加入到木纤维中,再与PP进行混炼,热压成型,制得复合材料。测试其力学性能并利用红外、扫描电镜进行表征。分析表明KH550能够很好地改性纳米Al_2O_3,添加纳米Al_2O_3改善了PP和木纤维之间的界面相容性,宏观上表现为力学性能提高。当纳米Al_2O_3添加质量分数为5%时,复合材料的力学性能提升最大,其弯曲强度、弯曲模量、冲击强度分别是43.79 MPa,3817 MPa,7.515 KJ·M2,对比未添加纳米粒子的复合材料分别提升55%、34%、21%。     

玉米秸秆/聚乳酸复合材料的制备及性能测试

近年来,在资源短缺和环境污染的压力下,生物可降解材料的开发与利用成为学者研究的热点之一。采用熔融共混的方法制备了一种玉米秸秆/聚乳酸生物可降解复合材料,并通过向复合材料中添加3种不同的改性剂对复合材料进行改性处理,旨在提高农林废弃物的附加值及改善复合体系的各项性能。采用X射线衍射、电镜扫描、接触角、力学性能测试等分析手段对复合材料的各项性能进行分析表征,对3种改性剂马来酸酐接枝聚乳酸(MAH-g-PLA)、马来酸酐(MAH)和硅烷偶联剂(KH-550)对复合材料的改性效果进行对比研究。X射线衍射分析的结果表明,MAH-g-PLA改性复合材料的结晶度变化不大,MAH改性复合材料的结晶度显著增加,而经过KH-550改性的复合材料的结晶度较未改性的复合材料有所下降。接触角分析结果表明经过改性之后的复合材料的表面接触角均有所增加,表明复合材料在改性之后的疏水性有所增加。其中MAHg-PLA改性的复合材料的接触角增加最多,表明MAH-g-PLA能够更好地改善复合材料的亲水性。扫描电镜的断面分析结果表明,MAH和KH-550均有效改善了复合材料的界面相容性,且KH-550改性的复合材料的界面相容性更佳并具有较高的力学强度。力学测试结果表明,KH-550改性的复合材料的拉伸强度提高了5.47%,弯曲强度提高了2.50%。     

MA-SEBS对木纤维/聚丙烯复合材料冲击断裂行为的影响(英文)

马来酸酐接枝苯乙烯-乙烯-丁烯-苯乙烯(MA-SEBS)用作聚丙烯/木纤维复合体系的界面相容剂及冲击改性剂,来提高其界面粘接及冲击强度。研究了MA-SEBS含量对PP/WF复合材料冲击断裂行为的影响,当MA-SEBS含量达到8%时,冲击性能达到了最大值,进一步增加到10%并未提高其断裂韧性,但动态热机械分析(DMA)表明复合材料刚性的提高,这归因于PP/WF界面的改善,当MA-SEBS超过8%,聚丙烯与木纤维分子间的相互作用增强。扫描电子显微镜(SEM)分析了样品的断裂表面,表明木纤维与聚丙烯表面强烈的界面粘结。图5表1参11。     

木纤维PP/PE共混物复合材料的流变和力学性能(英文)

For evaluation of the rheological and mechanical properties of highly filled wood plastic composites （WPCs）, polypropylene/polyethylene （PP/PE） blends were grafted with maleic anhydride （MAH） to enhance the interfacial adhesion between wood fiber and matrix. WPCs were prepared from wood fiber up to 60 wt.% and modified PP/PE was blended by extrusion. The rheological properties were studied by using dynamic measurement. According to the strain sweep test, the linear viscoelastic region of composites in the melt was determined. The result showed that the storage modulus was independent of the strain at low strain region （〈0.1%）. The frequency sweep resuits indicated that all composites exhibited shear thinning behavior, and both the storage modulus and complex viscosity of MAH modified composites were decreased comparing to those unmodified. Flexural properties and impact strength of the prepared WPCs were measured according to the relevant standard specifications. The flexural and impact strength of the manufactured composites significantly increased and reached a maximum when MAH dosage was 1.0 wt%, whereas the flexural modulus after an initial decreased, also increased with MAH dosage. The increase in mechanical properties indicated that the presence of anhydride groups enhanced the interracial adhesion between wood fiber and PP/PE blends.     

Dynamic-mechanical analysis and SEM morphology of wood flour/polypropylene composites

Introduction It is well known that over the past few decades, polymers have replaced many conventional materials, such as metal and wood in many applications. This is due to the advantages of polymers over conventional materials (Maurizio et al. 1998; Adr…     

新型木塑复合材料成型工艺的研究

木塑复合材料是以木材或各种木质纤维素纤维材料为基体 ,通过与塑料以不同复合途径形成的一种新型材料。文章介绍了平压法木塑复合材料成型工艺 ,研究了成型过程中板坯的流动性和粘结性 ,探讨了塑料与木质碎料的混合比对木塑复合材料力学性能的影响。结果表明将塑料先加入一定量的木粉或将木质材料与混炼后的塑料混合后压制成型 ,材料可以具有良好的力学性能     

聚丙烯比例对木塑复合材料性能的影响

通过正交试验,以木材纤维和废旧聚丙烯塑料为原料,异氰酸酯或马来酸酐作偶联剂,压制木材纤维/聚丙烯复合材料,研究聚丙烯(简称PP)用量对木塑复合材料性能的影响。结果表明,聚丙烯比例对复合材料的内结合强度、吸水厚度膨胀率、静曲强度和弹性模量有不同的影响。在热压时间、热压温度、复合材料密度相同的条件下,用异氰酸酯(简称MDI)作偶联剂,聚丙烯用量40%时复合材料的性能最佳;而用马来酸酐(简称MA)作偶联剂,聚丙烯用量50%时复合材料的性能最佳。     

Improvement in compatibility and mechanical properties of modified wood fiber/polypropylene composites

To improve the interfacial compatibility between wood fibers and polypropylene and the toughness of wood-fiber/polypropylene composites, maleic anhydride grafted polypropylene (PP-g-MAH) and maleic anhydride grafted styrene-ethylene-butadiene-styrene copolymers (SEBS-g-MAH) were used as modifiers. Mechanical properties of wood-fiber/polypropylene (WF/PP) composites were improved when PP-g-MAH or SEBS-g-MAH was added. When either of these copolymers was added, the composites had better interfacial compatibility than the unmodified composite. This was verified by scanning electron microscope (SEM) observations and dynamic mechanical analysis (DMA). The mechanical properties of the composites were significantly improved because of the good interfacial bonding between wood fibers and polypropylene when PP-g-MAH and SEBS-g-MAH were added. __________ Translated from Journal of Beijing Forestry University, 2007, 29(2): 133–137 [译自: 北京林业大学学报]     

HDPE含量对木塑复合材料力学性能的影响

通过改变高密度聚乙烯(HDPE)和聚苯乙烯(PS)的混合比例,设计了7种制作木塑复合材料的方案,HDPE∶PS分别为0∶10、1∶9、2∶8、3∶7、4∶6、5∶5、10∶0。按照不同设计方案,选用相应的挤出工艺参数制作木塑复合材料型材,按照塑料检测标准对其进行力学性能检测以及扫描电镜观察,找出最优的配方工艺。     

植物纤维/塑料复合材作地板基材的研究

Three kinds of composites （fiber/Polypropylene, fiber/Polyethelene, and fiber/Polystyrene） were made by using hot pressing process for substrate of floorboard and the properties of each kind of composites were tested. MORs of PP/wood fiber, PS/fiber, and PE/fiber composites with coupling agent added were raised by 18.4%, 37.1%, and 42%. respectively, compared to those without coupling agent. Among the three kinds of fiber/plastic composites, fiber/PP composite has best mechanical properties, and it can meet quality standard of eligible grade product and come up to the excellent grade products of China when the coupling agent is added. The performance of composite made of PE/fiber or PS/fiber can exceed qualified product grade only with coupling agent added.     

Fundamental studies on wood/cellulose-plastic composites: effects of composition and cellulose dimension on the properties of cellulose/PP composite

Although wood/cellulose-plastic composites (WPC) of low wood/cellulose content have been more accepted worldwide and are promoted as low-maintenance, high-durability building products, composites containing high wood/cellulose content are not yet developed on an industrial scale. In this study, flow properties, mechanical properties, and water absorption properties of the compounds of cellulose microfiber/polypropylene (PP) and maleic anhydride-grafted polypropylene (MAPP) were investigated to understand effects of the high cellulose content and the dimensions of the cellulose microfiber. The molding processes studied included compression, injection, and extrusion. It was found that fluidity is not only dependent on resin content but also on the dimension of the filler; fluidity of the compound declined with increased fiber length with the same resin content. Dispersion of the composite was monitored by charge-coupled device (CCD) microscope. Increasing the plastic content in the cellulose-plastic formulation improved the strength of mold in addition to the bond development between resin and filler, and the tangle of fibers. The processing mode affected the physicomechanical properties of the cellulosic plastic. Compression-molded samples exhibited the lowest modulus of rupture (MOR) and modulus of elasticity (MOE) and the highest water absorption, while samples that were injection-molded exhibited the highest MOR (70 MPa) and MOE (7 GPa) and low water absorption (2%).     

Hygroscopic thickness swelling rate of composites from sawdust and recycled plastics

The thickness swelling rates of compression molded wood plastic composites (WPCs) prepared from 50% by weight sawdust and 50% by weight virgin and/or recycled plastics (HDPE and PP) were studied. Thickness swelling rates of the manufactured WPCs were evaluated by immersing them in water at room temperature and monitoring thickness changes for several weeks. A swelling model developed by Shi and Gardner (Composites Part A, 37:1276–1285, 2006) was used to study the thickness swelling process of WPCs. The parameter K _SR of the model can be used to quantify the swelling rate. The results indicated that composites containing PP had lower equilibrium thickness swelling and also shorter equilibrium time (time to reach equilibrium thickness swelling). The swelling model developed was a good predictor of the hygroscopic swelling process of wood plastic composites. Composites containing PP (virgin and recycled) had higher K _SR than those containing HDPE. The minimum and maximum K _SR values were observed in composites made of virgin HDPE and a mixture of recycled plastics, respectively. With increasing recycled plastic content K _SR linearly decreased.