热致液晶共聚酯/PA6/RSMA原位复合材料2.力学性质与破坏行为

选用Vectra A950热致液晶共聚酯（LCP）制备热致液晶共聚酯（LCP）/聚酰胺6（PA6）/苯乙烯-马来酸酐无规共聚物（RSMA）三元共混物。并注射成型制得复合板材。研究三元LCP/PA6/RSMA原位复合材料的形态结构、力学性质和破坏行为。结果表明,PSMA是LCP/PA6复合材料的有效增容剂。RSMA的加入有利于LCP在PA6基体中原位成纤,增强了两相之间的界面粘接。加入RSMA后,LCP/PA6原位复合材料的杨氏模量、抗拉强度和抗冲击强度明显提高。RSMA能延长LCP/PA6复合材料的裂纹引发时间、增加裂纹引发能和总冲击能。对LCP/PA6原位复合材料有增韧作用。RSMA的加入量存在一临界值。     

动态硫化制备多壁碳纳米管/热塑性硫化胶复合材料的相态结构及热电效应

采用动态硫化方法制备了多壁碳纳米管/热塑性硫化胶(MWCNTs/TPV)复合材料,研究了三种动态硫化工艺和MWCNTs用量对MWC-NTs/TPV复合材料的相态结构、介电、导热和物理性能的影响.MWCNTs/TPV复合材料呈现"海岛"结构,IIR橡胶相以微米级交联颗粒分散在PP相中.动态硫化工艺主要影响MWCNTs的分布,MWCNTs在两相中均匀分布的MWCNTs/TPV复合材料具有较高的热电性能.当MWC-NTs含量达到渗流阈值(3％(质量分数,下同))时,形成MWCNTs网络结构,MWCNTs/TPV复合材料的交流电导率、介电常数和热导率急剧增加.随着MWCNTs含量的增加,MWCNTs/TPV复合材料的弹性模量逐渐增大,拉伸强度先增大后减小;MWCNTs能够提高TPV基体的界面结合力,与纯TPV相比,当MWCNTs的含量为3％时,MWCNTs/TPV复合材料的拉伸强度提高39％.基于MWCNTs/TPV复合材料的相态结构以及MWCNTs的渗流阈值提出MWCNTs网络结构,分散在PP基体中和两相界面处的MWCNTs相互搭接形成MWCNTs网络结构.     

MA-SEBS增容PP/SiO_2纳米复合材料的力学性能与结晶行为

聚丙烯/二氧化硅(PP/SiO2)纳米复合材料具有优异的加工、力学、热稳定等性能。如何实现SiO2在PP基体中的均匀分散及提高两相的界面相容性是制备PP/SiO2复合材料的关键。文中利用马来酸酐接枝的氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(MA-SEBS)作增容剂,采用熔融共混和注塑成型的方法制备了PP/SiO2纳米复合材料;研究了MASEBS对PP/SiO2复合材料的力学性能、断面形貌及结晶行为的影响。结果表明:添加MA-SEBS显著提高了PP/SiO2复合材料的冲击强度,使SiO2在PP结晶过程中能更好地起到异相成核作用,提高了复合材料中PP相的结晶温度、降低了PP的球晶尺寸。     

固相剪切碾磨制备聚丙烯/废旧橡胶/聚烯烃弹性体复合材料

利用固相剪切碾磨技术在常温下制备了聚丙烯(PP)/废旧轮胎橡胶(GTR)/聚烯烃弹性体(POE)复合材料。采用力学性能测试、差热分析(DSC)和扫描电镜(SEM)对固相剪切碾磨制备的GTR/POE复合粉体和相应PP/GTR/POE复合材料进行表征和分析,研究了碾磨次数和GTR/POE含量对PP/GTR/POE复合材料结构与性能的影响。结果表明,对固相剪切碾磨方法制备的PP/GTR/POE复合材料,GTR和POE被有效粉碎和均匀分散,其冲击强度和断裂伸长率比常规熔融共混方法制备的复合材料高;增加GTR/POE共碾磨复合粉体的含量或增加碾磨次数均可提高冲击强度和断裂伸长率。     

超分散剂对剑麻纤维/长玻纤/聚丙烯复合材料性能的影响

以自制超支化分散剂(HBD)为改性剂,制备剑麻纤维(SF)/长玻纤(LGF)/聚丙烯(PP)复合材料,探讨超分散剂对SF/LGF/PP复合材料的力学性能、热性能、结晶性能的影响。采用扫描电镜(SEM)观察SF/LGF/PP复合材料的冲击断面形貌,分析纤维与聚丙烯树脂的界面相容性。实验结果表明,经HBD改性后的SF/LGF/PP复合材料的冲击强度、弯曲强度分别比未经分散剂改性的复合材料提高了35.2%和6%,复合材料的热稳定性、聚丙烯相的结晶速率和结晶度有所提高,HBD的加入使得复合材料的储能模量提高,损耗系数降低。     

聚丙烯/木粉复合材料的增容改性及其机理

为进一步改善聚丙烯(PP)/木纤维(WF)复合材料的力学性能,采用几种不同类型的马来酸酐接枝型相容剂对PP/WF复合材料进行增容改性,并通过红外光谱和扫描电镜,分析和研究其增容机理。结果表明,PP-g-MAH的改性效果最为明显,当其添加量为m(PP-g-MAH)/m(WF)=10/100时,PP/WF复合材料的拉伸强度提高40.9%,弯曲强度提高47.3%,弯曲模量提高35.3%。PP-g-MAH使PP与木粉产生良好的增容效果,木粉颗粒被PP包裹,材料抵抗外应力以及材料破坏由发生在两相界面变成发生在材料整体,从而有效提高了复合材料的力学性能。     

固相剪切碾磨制备聚丙烯/层状双金属氢氧化物纳米复合材料的力学性能及热稳定性

采用湿法固相剪切碾磨法(S<'3>M)制备了部分剥离型聚丙烯(PP)/层状双金属氢氧化物(LDHs)纳米复合材料,研究了PP/LDHs纳米复合材料的力学性能和热稳定性.结果表明,相对于聚丙烯,固相剪切碾磨制备的PP/LDHs纳米复合材料可在拉伸强度保持不变的情况下,明显提高其断裂伸长率和冲击强度.如当LDHs质量分数为...     

竹纤维组合形态对竹纤维/聚丙烯复合材料性能的影响

以聚丙烯（PP）为基体,单根竹纤维（SBF）和竹纤维束（BFS）两种形态竹纤维为增强体,采用无纺气流铺装-模压工艺制备了SBF-BFS/PP复合材料。通过力学试验机、SEM、TGA、DSC等对SBF-BFS/PP复合材料的力学性能、微观形貌、热性能等进行表征,研究竹纤维形态配比变化对SBF-BFS/PP复合材料综合性能的影响。结果表明,在纤维总含量不变情况下,SBF在两种形态竹纤维中的含量逐步增加时,SBF-BFS/PP复合材料冲击强度和弹性模量逐步增加; SBF在两种形态竹纤维中质量分数为90wt%时,SBF-BFS/PP复合材料冲击强度和弹性模量比SBF质量分数为10wt%时分别提高了26.46%和38.39%; SEM结果表明,竹纤维与PP基体存在较差界面相容性,竹纤维出现断裂和拔出等现象;热失重结果表明,随着SBF含量的增加,SBF-BFS/PP复合材料的耐热性能并没有明显变化。此外,对SBF-BFS/PP复合材料的耐水性能测试结果表明,由于SBF比表面积大,随SBF含量的增加,SBF-BFS/PP复合材料中易吸水组分增加,从而导致其耐水性能下降。      

凹凸棒石/弹性体协同改性聚丙烯

通过熔融共混法,制得了聚丙烯(PP)/硅烷偶联剂改性的天然凹凸棒石(OATT)/聚烯烃弹性体(POE)三元复合材料和PP/OATT、PP/凹凸棒石(ATT)二元复合材料,研究了复合材料的力学性能、流变性能和热性能。力学性能研究结果表明:在二元体系中,复合材料的拉伸强度随着ATT和OATT含量提高而提高,但是在相同凹凸棒石含量下,PP/OATT复合材料的拉伸强度提高更显著;PP/ATT复合材料的冲击强度与纯PP比较没有提高反而下降,而PP/OATT的冲击强度则随着OATT含量提高先增后降,并在OATT含量为1%时达到最大值。在PP/OATT/POE三元体系中,当固定PP/OATT比例为100/5时,POE含量达到5%,复合材料冲击强度为8.91KJ/m2,与未加POE体系相比提高了21.10%;当POE含量增加到15%时,复合材料冲击强度提高了44.80%,并且其拉伸强度基本得到保持,说明POE和OATT对PP具有明显的协同增韧增强效果。流变曲线分析表明,在低的剪切速率下,改性的凹凸棒石对PP复合材料的流动性能有较好改善。DSC分析结果表明,POE和OATT均能有效地促进PP结晶,并且OATT/POE二元组分对...     

三聚氰胺聚磷酸盐对竹纤维/聚丙烯复合材料力学及阻燃性能的影响

采用三聚氰胺聚磷酸盐（MPP）作为阻燃剂,加入到竹纤维/聚丙烯（BF/PP）复合毡中,制备MPP-BF/PP复合材料。采用力学测试和SEM研究MPP对MPP-BF/PP复合材料力学性能和微观形貌的影响;采用极限氧指数（LOI）、热失重（TG）和吸水率为指标研究MPP对MPP-BF/PP复合材料阻燃性、热稳定性和耐水性的影响。测试表明:MPP的质量分数小于30wt%时,MPP-BF/PP复合材料弯曲强度和冲击强度随MPP质量分数的增加先增大后减小,当MPP质量分数达到5wt%时,MPP-BF/PP复合材料呈现出最佳的弯曲强度和冲击强度;MPP在MPP-BF/PP复合材料内部均匀分布,而随着MPP质量分数的增加,MPP-BF/PP复合材料断裂面的粗糙度明显提高,即MPP与PP界面相容性变差,使其力学性能降低。LOI测试结果表明,MPP可以有效提高MPP-BF/PP复合材料的阻燃性能,当MPP质量分数为30wt%时,MPP-BF/PP复合材料LOI达到24.3%。热失重测试表明,MPP的加入可提高MPP-BF/PP复合材料的热分解温度,促进其残炭率明显增大,有利于提高MPP-BF/PP复合材料阻燃性能。耐水性能测试结果表明,MPP质量分数小于20wt%时,MPP对MPP-BF/PP复合材料的耐水性能没有明显影响。采用模糊综合评价法分析表明,MPP质量分数为10wt%时,MPP-BF/PP复合材料性能最优。      

Structure and mechanical properties of the extruded blends of a liquid crystalline polymer with polypropylene

Blends of a thermoplastic, isotatic polypropylene (PP) and a liquid-crystalline polymer (LCP) based on a copolyester of hydroxynapthoic acid and hydroxybenzoic acid, were extruded. The LCP exhibited a higher viscosity than that of the PP under the extrusion conditions. Calorimetric, microscopic, static and dynamic mechanical tests were performed on these blends. Differential scanning calorimetry thermograms indicated that the crystallization temperature of PP increases slightly with increasing LCP content. Scanning electron microscopy examinations revealed that the LCP phase was elongated into microfibrils in the blends investigated. However, some undeformed spherical droplets were dispersed in the PP matrix in addition to microfibrils for the blends containing high LCP concentrations. Static tensile tests showed that the addition of LCP to PP results in an increase of the modulus of elasticity but a decrease in tensile strength. The storage modulus of the extruded blends was found to increase with the addition of LCP.     

纳米MgO/高密度聚乙烯复合材料的性能

通过熔融共混法制备了纳米MgO/高密度聚乙烯(nano-MgO/HDPE)复合材料, 并对该复合材料的力学性能进行了测试, 用SEM对nano-MgO在nano-MgO/HDPE复合材料中的分散情况进行了观测, 通过紫外可见光谱研究了复合材料的紫外屏蔽性能, 通过TG研究了复合材料的热稳定性, 通过DSC研究了复合材料的结晶性能。结果表明:虽然nano-MgO的引入使HDPE的热分解温度有所降低, 但nano-MgO的引入提高了HDPE的冲击强度、弯曲强度及紫外屏蔽性能。当nano-MgO含量为2wt%时, nano-MgO/HDPE复合材料的冲击强度比纯HDPE高14%。当nano-MgO含量为4wt%时, nano-MgO/HDPE复合材料的弯曲强度比纯HDPE高18%。nano-MgO在nano-MgO/HDPE复合材料中的分散均匀, 且nano-MgO的引入可以促进HDPE的结晶。      

Mechanical properties of injection moulded blends of polypropylene with thermotropic liquid crystalline polymer

Blends of a thermotropic liquid crystalline polymer (LCP) with polypropylene (PP) were injection moulded. The LCP exhibited a higher viscosity than that of PP. Static and dynamic mechanical measurements, Izod impact tests, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) were performed on these blends. The static tensile tests show that the tensile modulus and strength of PP are improved with the addition of LCP. The improvement in mechanical properties is associated with the formation of LCP fibrils as evidenced by SEM observations. Dynamic studies on these blends show an increase in the storage modulus but a decrease in loss factor with the addition of LCP. Furthermore, TGA measurements show that the thermal stability of PP is improved substantially with the addition of LCP.     

Effect of fillers on the structure and mechanical properties of LCP/PP/SiO2 in-situ hybrid nanocomposites

Fibrillation of LCP in a LCP/PP blend was enhanced through the introduction of nanosized silica particles to the PP matrix. LCP/(PP/SiO₂) composites with various silica concentrations were injection moulded into 1 mm plaques and characterized using structural, morphological and mechanical methods. The results revealed the transformation of short LCP fibrils to high aspect ratio fibrous structures upon the addition of the nanofillers. The silica particles have promoted the shear-induced fibrillation of the LCP phase. The wide angle X-ray diffraction results indicated that high orientation was achieved with rising silica content. The injection moulded samples also showed increased mechanical anisotropy with rising filler content. Consequently, both the in-situ fibrillation of LCP and silica reinforcements imparted good tensile strength and modulus to the composites along the flow direction. Such an improvement was achieved from the basis of increasing the matrix viscosity and raising the Capillary number which is a dimensionless factor governing the fibrillation process. This novel approach opens a new insight to the feasibility of producing in-situ hybrid nanocomposites with synergetic reinforcements.     

PP/LCP composites: effects of shear flow,extensional flow and nanofillers

PP/LCP composites moulded under shear flow and extensional flows were prepared in this work. It was observed that the predominating shear flow during injection moulding was unable to induce in-situ reinforcements in the Rodrun LC5000/PP blend. With the introduction of an additional drawing process, fibrous LCP was developed. The fibrillation of the LCP phase was found to increase with the draw speed and the formation of LCP fibrils was manifested as higher strength and stiffness. However, due to the poor adhesion between the pre-generated LCP fibrils and PP matrix, the strength of the extensional PP/LCP composites was lower than that of direct injection moulded LCP/PP blend. In another approach, silica fillers were introduced to the LCP/PP blend and the LCP fibrillation was found to improve. The nanosilica was believed to behave as a viscosity thickening agent and was able to promote the LCP droplet-fibril transition effectively. The nanofiller/LCP/thermoplastic system possessed dual reinforcements which imparted good properties to the composite.     

SiC填料对光伏封装用EVA导热复合胶膜的影响

目的探讨乙烯-醋酸乙烯酯共聚物(EVA)胶膜中加入晶须碳化硅(SiC)无机填料后,对EVA胶膜交联度、力学性能及导热性能的影响。方法通过将晶须SiC无机填料导入EVA,使得在整个体系内呈连续相的有机大分子与呈分散相的无机填料共混成一体,再通过挤出流延成形得到厚度均一的胶膜。结果随着晶须SiC含量的增加,EVA复合胶膜的抗拉强度和断裂伸长率均有所下降。交联度随着SiC含量的增加而略微增大,最终达到平衡,剥离强度先增大后减小。使用不同的偶联剂对SiC表面进行处理,EVA导热复合胶膜导热性能存在差异。使用同一种偶联剂对SiC表面进行处理,SiC粒径尺寸的差异同样对EVA导热复合胶膜导热性能存在差异。结论添加晶须SiC的尺寸规格、添加量、表面处理情况对EVA导热复合胶膜的力学性能、交联度影响较大。     

R-PET短纤维增强PP复合材料的结构与性能

对再生聚对苯二甲酸乙二醇酯(R-PET)短纤堆增强聚丙烯(PP)复合材料进行了研究.通过扫描电镜(SEM)、熔融指数仅、差示扫描量热法(DSC)和万能试验机测定了材料的相结构、加工性能、热学性能和力学性能.采用甲基丙烯酸酸水甘油酯接枝乙烽-辛烯共聚物(POE-g-GMA)作为体系的增容剂.结果表明,POE-g-GMA显...     

聚丙烯/聚苯乙烯共混合金Ⅱ.结晶和性能

用偏光显微镜、DSC、DMA分析法和拉伸试验等方法对PP／PS／PP-g-PS熔融共混合金的结晶行为、形态和拉伸强度进行了研究。结果表明，PP-g-PS减轻了PS相对PP相结晶行为的干扰，合金的拉伸强度明显上升。上述变化均与PP-g-PS在合金中的含量有关。     

滑石粉/聚丙烯复合材料结晶度与相间形态对其力学性能的影响

用偶联剂改性的滑石粉（Talc）与聚丙烯（PP）共混制备Talc／PP复合材料,测试了复合材料的力学性能。用广角X射线衍射仪对聚丙烯的结晶状况进行了表征,计算了复合材料中聚丙烯的结晶度;用扫描电镜观察了样条的断口形貌,讨论了滑石粉填充量对材料结晶性能与相态结构的影响．以及PP相结晶度和体系的微相结构对复合材料的拉伸、弯曲及冲击性能的影响。实验结果表明,滑石粉的加入对复合材料的结晶行为、相态结构和力学性能有影响。在15％的滑石粉填充量时,聚丙烯相的结晶度达到最大值,材料的拉伸强度、弯曲强度也基本上达到最大值,而冲击强度却降到最低。扫描电镜照片显示,PP基体的结晶形态与复合材料的相态结构随滑石粉含量的改变而变化。     

聚丙烯/聚烯烃弹性体/硅灰石复合材料的制备与热学力学性能

采用熔融共混的方法制备聚丙烯(PP)/聚烯烃弹性体(POE)/硅灰石(Wollastonite)复合材料,利用万能材料试验机、悬臂梁冲击机、差热扫描量热仪(DSC)和扫描电镜(SEM)研究了聚烯烃弹性体和硅灰石对聚丙烯的力学性能及热性能的影响。结果表明,POE弹性体对PP有很好的增韧作用,提高了PP的冲击强度,硅灰石在一定程度上有增强的作用,提高了PP/POE的拉伸强度;POE和硅灰石使复合材料的结晶温度有所提高,但使熔点有所降低。当POE占3%(质量分数,下同),硅灰石占3%时,复合材料的热学、力学性能最优,冲击强度比纯PP高出15.4%,拉伸强度高出2.6%,结晶温度高出5℃。