Nano-CaCO_3填充PP复合材料断口形貌的分形特征及对冲击强度的影响

用熔融共混法将改性纳米碳酸钙(nano-CaCO_3)填充到聚丙烯(PP)树脂中制备PP/nano-CaCO_3复合材料。通过冲击试验测定了纳米复合材料的冲击强度,采用扫描电镜观测了材料的断口形貌,运用图像处理软件IPP提取了纳米复合材料的断口形貌的轮廓曲线;应用结构函数法测算了断口形貌轮廓曲线的分形维数(D_l),探讨了D_l与复合材料冲击强度(σ_Ⅳ)的关系。结果表明:PP及其PP/CaCO_3纳米复合材料的断口形貌具有显著的分形特征,其D_l值介于1.6375至1.8952之间。在所考察的体积填充分数(φ_f)范围内,D_l值总体上随φ_f的增加而增大,纳米复合材料的σ_Ⅳ值随φ_f的增加而增大;在相同的φ_f下,钛酸酯偶联剂改性CaCO_3填充的PP纳米复合材料(SII)较脂肪酸改性CaCO_3填充的PP纳米复合材料(SI)有更高的D_l值和σ_Ⅳ值,且其σ_Ⅳ与D_l呈正相关关系。     

PP/改性纳米CaCO3复合材料力学性能与断裂形态研究

制备了反应性单体改性纳米CaCO3填充PP复合材料，研究了反应性单体丙烯酸(AA)和苯乙烯(St)在有、无过氧化二异丙苯(DCP)存在下改性纳米CaCO3填充PP复合材料的力学性能，并用扫描电子显微镜(SEM)研究了复合材料弯曲断面的形态。结果表明，PP／改性纳米CaCO3的力学性能优于PP／微米CaCO3的力学性能；在DCP存在下，AA、AA与St混合改性可使PP／纳米CaCO3的拉伸性能和弯曲性能提高，减小拉伸强度随CaCO3含量增加而下降的趋势；并可有效提高纳米CaCO3在基体中的分散性和界面粘结性。     

无机填料/PP复合材料的力学性能和加工性能

研究无机填料(碳酸钙(CaCO3)、玻璃微珠(GB)和硫酸钙晶须(CSW))对聚丙烯(PP)力学性能和加工性能的影响.SEM观察PP复合材料冲击缺口的断面微观形貌和无机填料在PP基体中的分散情况.结果表明:当CSW舍量为6份时,PP/CSW复合材料的缺口冲击强度达到最大值5.9 kJ/m2.当无机填料含量为6份时,PP/CaCO3、PP/GB和PP/CSW复合材料的拉伸强度达到最大值.随着CaCO3、GB和CSW含量的增加,PP复合材料的加工平衡扭矩逐渐下降.     

玻璃微珠填充聚丙烯复合材料的力学性能研究

用硅烷偶联剂对玻璃微珠(GB)进行表面改性,采用熔融共混法制备了GB填充聚丙烯(PP)复合材料,考察了PP/GB复合材料的力学性能。结果表明:随着GB用量的增加,复合材料的断裂伸长率降低;拉伸弹性模量呈非线性形式增加;拉伸强度开始下降速率较快,然后趋于平缓;复合材料的冲击强度先随GB用量的增加而增加然,后降低;偶联剂处理GB有利于复合材料力学性能的改善。     

硫酸钡/聚丙烯复合材料的力学性能及形态结构

采用铝酸酯和钛酸酯偶联剂对BaSO4进行表面处理,通过熔融共混制备了聚丙烯(PP)/BaSO4复合材料。研究了BaSO4粒径和填充量、偶联剂种类及用量对PP/BaSO4复合材料力学性能、流动性能的影响。结果表明:BaSO4粒径越小,在基体树脂中的分散性越好,复合材料的韧性改善越明显;采用偶联剂处理的BaSO4对PP进行填充改性,可有效提高复合材料的冲击韧性和断裂伸长率,使用铝酸酯偶联剂处理的改性效果明显优于钛酸酯偶联剂;在PP/BaSO4复合材料试样的冲击断面上存在许多粒子抽出后留下的孔穴,而孔穴的形成使复合材料的韧性得到提高。     

几种加工助剂在聚丙烯基木塑复合材料中的应用对比

研究了3种加工助剂对聚丙烯(PP)基木塑复合材料物理力学性能和加工性能的影响,并利用扫描电子显微镜对复合材料的冲击断面进行了分析。结果表明,在一定用量范围内,芳香族碳氢化合物(S-105)和改性烷基酚醛树脂(TKM-M80)能够提高木粉在PP基体中的分散性,改善基体与木粉之间的相容性,从而提高PP基木塑复合材料的拉伸强度、冲击强度、弯曲强度、弯曲弹性模量和加工性能;脂肪醇和脂肪酸酯的混合物(Deoflow A)能够明显提高木粉在PP基体中的分散性和复合材料的加工性能,但用量较大时对复合材料的拉伸强度、弯曲强度和弯曲弹性模量有不利影响。     

PP/针形纳米CaCO3复合材料的力学性能

用硬脂酸皂化改性针形纳米CaCO3表面后,将其与聚丙烯(PP)共混、挤出和注塑,制成PP／CaCO3纳米复合材料。与纯PP相比,填充针形纳米CaCO3的体积分数为4.21％时,PP体系的冲击强度和断裂伸长率分别提高了49％,339％,拉伸强度下降2．7％。改性后的纳米CaCO3与PP之间的界面作用与改性前相比有所减弱,冲击断面扫描电子显微镜照片显示,针形纳米CaCO3均匀地分散在PP基体中。偏光显微照片显示,针形纳米CaCO3对PP有明显的异相成核作用。     

超细重质碳酸钙填充聚丙烯的研究

利用双螺杆挤出机制备了超细重质CaCO3填充聚丙烯(PP)复合材料。测得了PP/超细重质CaCO3复合材料的力学性能。采用SEM、XRD、DSC对PP/超细重质CaCO3复合材料进行了研究。结果表明:超细重质碳酸钙在基体中基本实现了良好分散;在一定填充范围内,超细重质CaCO3的加入可以极大的提高复合材料的冲击强度;复合材料的结晶度随超细重质碳酸钙填充量的增加而有所降低,但复合材料的熔点变化不大。     

矿物填充改性聚丙烯熔接痕强度研究

研究了聚丙烯(PP)基体的熔体质量流动速率、矿物填充剂填充量、矿物填充剂类型等因素对填充改性聚丙烯复合材料熔接痕强度的影响。结果表明,矿物填充剂的形态结构和填充量是影响矿物填充改性聚丙烯复合材料熔接痕强度的关键因数。颗粒状矿物填充PP复合材料的熔接痕强度保持率最好,片层结构的矿物填充剂会显著降低矿物填充PP复合材料的熔接痕强度。     

HDPE对共聚PP/CaCO3高填充复合材料的增韧

以双螺杆挤出机制备了高密度聚乙烯(HDPE)增韧共聚聚丙烯(PP)/CaCO3(质量比50.0/50.0)高填充复合材料,并对其增韧机制进行了探讨.结果表明:在共聚PP/CaCO3高填充复合材料中添加1.5份的HDPE,可使其缺口冲击强度提高46%;共聚PP与HDPE之间的良好浸润性使界面处大分子的相互渗透得以增强;在外力作用下,共聚PP/CaCO3/HDPE高填充复合材料中的HDPE颗粒与共聚PP基体之间发生脱黏并诱发周围基体发生强烈塑性形变,使断面撕裂带细化并吸收更多冲击能量.     

Mechanical properties and morphologies of polypropylene with different sizes of glass bead particles

A commercial grade of isotactic polypropylene (PP) was used to study the mechanical properties and morphologies of the PP composites filled with four sizes of glass bead particles. The glass bead particles used were with average particle sizes of 15 μm (GB15), 10 μm (GB10), 5 μm (GB5), and 2.5 μm (GB2.5), respectively. It was clear that the glass bead size was an important factor on the determination of mechanical properties of the composites. As a whole, in view of the scatter in the data, under the condition of same filler content, the yield strength and impact strength of the composites filled with smaller glass bead particles was higher than those of the composites filled with bigger ones. And the flexural strength and modulus of the composites filled with GB10, GB5, or GB2.5 particles could be regarded as the same. The flexural strength and modulus of the composites filled with GB15 particles were higher than those of the composites filled with other three sizes of particles. Among four sizes of glass bead particles, GB2.5 had the best toughening effect to improve the impact strength of PP matrix. And the major toughening mechanism of the PP/GB2.5 composites was the pinning effect introduced by GB2.5. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

玻璃微珠改性PP和LLDPE力学性能的比较研究

采用玻璃微珠(GB)改性聚丙烯(PP)和线性低密度聚乙烯(LLDPE)，对玻璃微珠的用量、粒径和复合材料加工方法对材料的力学性能的影响进行了比较研究。结果表明：随着GB用量的增加，单、双螺杆挤出GB／PP复合材料的拉伸模量、弯曲强度和弯曲模量均呈线性增长的趋势，而屈服强度则有小幅下降；断裂应变在低含量时有所提高，然后迅速下降；单双螺杆挤出材料的冲击强度均有所提高，并在一定范围内随GB用量的提高而增大，且单螺杆挤出材料的冲击强度略高于双螺杆挤出材料。而GB／LLDPE中，随着GB用量的增加，单螺杆挤出复合材料的拉伸模量、弯曲模量均呈线性增长趋势，而屈服强度和弯曲强度在含量较高时略有上升；双螺杆挤出复合材料的拉伸模量、屈服应力、弯曲强度和弯曲模量均呈线性增长的趋势，两者的断裂应变都有所降低，但没有严重劣化LLDPE复合材料的冲击特性。GB的粒径对两种复合材料的力学性能影响不大，但对GB／PP复合材料的韧性有较大影响。单、双螺杆挤出GB／PP复合材料的冲击强度在一定范围内较纯料有一定提高；同样的，双螺杆挤出复合材料的冲击强度低于单螺杆挤出材料。     

动态固化聚丙烯／马来酸酐接枝聚丙烯／滑石粉／环氧树脂复合材料研究

将动态硫化技术应用于热塑性树脂／填料／热固性树脂复合体系，制备了动态固化聚丙烯(PP)／马来酸酐接枝PP(PP-g-MAH)/滑石粉(Talc)／环氧树脂(EP)复合材料。研究了动态固化PP／PP-g-MAH/Talc／EP复合材料的界面作用、形态结构、力学性能以及热稳定性。实验结果表明：PP／PP-g—MAH的加入，可明显增加PP/Talc复合材料的界面作用。在动态固化PP／PP-g-MAH/Talc／EP复合材料中，PP和Talc两相界面更加模糊，动态固化EP进一步增加了PP和Talc间的界面作用。当EP的用量超过5份时，部分EP呈颗粒状分布在PP基体中。与PP／PP-g-MAH/Talc／EP和PP／PP-MAH-Talc／EP复合材料相比，动态固化PP／PP-g-MAH/Talc／EP复合材料的冲击强度、拉伸强度和弯曲模量均有明显提高。当EP用量超过5份时，复合材料的冲击强度和断裂伸长率明显降低，但拉伸强度和弯曲模量继续增加。热分析表明动态固化PP／PP-g-MAH/Talc／EP复合材料具有较高的热稳定性。     

Mechanical properties of wood-fiber/toughened isotactic polypropylene composites

This study investigates the mechanical properties of wood-fiber/toughened PP composite modified by physical blending with an EPDM rubber to improve impact toughness. Wood-fiber thermoplastic composites were prepared with a modified PP matrix resin, employing high shear thermokinetic compounding aided with maleated PP for the fiber dispersion. The addition of EPDM improved the impact toughness, while it reduced stiffness and strength properties. To compensate the non-plane strain fracture toughness, the specimen strength ratio (R_sb) was adopted as a comparative measure of fracture toughness. The strength ratio increased with the addition of EPDM, while it decreased with increasing wood-fiber concentration. The work of fracture increased with EPDM level except at large wood-fiber concentration. The effectiveness of the impact modification was assessed with the balance between tensile modulus and unnotched impact energy as a function of wood-fiber concentration. EPDM rubber modification was moderately effective for wood-fiber PP composites. The examination of fracture surfaces showed twisted fibers, fiber breakage, and fiber pull-out from the matrix resin.     

表面改性对聚丙烯/微米氢氧化镁复合材料性能的影响

研究了表面处理剂（钛酸酯和硅烷偶联剂）和原位聚合方法对聚丙烯/微米氢氧化镁（MH）复合材料的力学性能及流变性能的影响。采用DSC、SEM和毛细管流变仪对PP/MH（80/20）复合材料的性能进行了研究。结果表明：原位聚合改性后的微米MH与PP基体间的界面黏结力得到了加强,复合材料的冲击强度较填充未改性MH的复合材料提高了26.4 ％。在PP基体中添加聚合物包覆改性微米MH粒子的复合材料熔体流动速率较纯PP上升了64 ％。在相同剪切速率下,填充聚合物包覆改性MH的复合材料熔体表观黏度明显低于填充未改性微米MH的复合材料,表明聚合物包覆改性后的MH降低了其对PP熔体流动的阻碍作用,改善了PP/MH复合材料的流动性能。     

Effect of clinoptilolite filler on the physical and mechanical properties of polypropylene

This study aims to investigate the mechanical and physical properties of polypropylene (PP) filled by natural zeolite. For this purpose, a natural zeolite (at 1–6 wt% filler loadings) with two different particle sizes was used. Two different kinds of silane coupling agents (3‐aminopropyltriethoxysilane, GAPTES and 3‐glycidoxypropyltrimethoxysilane, GPTMS) at three different volume ratios were used to improve the zeolite compatibility with PP and to improve the mechanical properties of composites. Fillers and PP were compounded with a twin screw extruder, and the composites were moulded with injection moulding press. The samples were subjected to mechanical tests (i.e., impact and tensile tests) and physical tests (i.e., hardness, density, and melt flow index, MFI). The physical test results showed that the levels of hardness and density of both unmodified and modified zeolite‐filled PP composites were higher compared with neat PP. The MFI values of composites were decreased by increasing zeolite loading level. Composites including GAPTES modified zeolite showed improved yield strength, impact strength and stiffness compared with composites filled with unmodified zeolite particles. POLYM. COMPOS. 34:1396–1403, 2013. © 2013 Society of Plastics Engineers     

Crystallization behavior and mechanical properties of polypropylene/modified carbon black composites

Carbon black (CB) modified with small organic molecules was filled in polypropylene (PP) matrix. The crystallization behavior and mechanical properties of PP/modified CB (MCB) composites were investigated. Compared with the original CB, MCB could be dispersed uniformly in smaller particle sizes in PP matrix, and MCB could act as a more effective nucleating, toughening, and reinforcing agent when it was filled in PP at low concentrations. Further increasing of MCB particles in PP matrix resulted in the decrease of impact and tensile strength of PP/MCB composites. It was inferred from DSC results that the existence of CB vand MCB in PP matrix could result in the decrease of crystallite size and degree of perfection of PP. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Morphology and mechanical properties of polypropylene/organoclay nanocomposites

Polypropylene (PP) nanocomposites were prepared by melt intercalation in an intermeshing corotating twin‐screw extruder. The effect of molecular weight of PP‐MA (maleic anhydride‐ modified polypropylene) on clay dispersion and mechanical properties of nanocomposites was investigated. After injection molding, the tensile properties and impact strength were measured. The best overall mechanical properties were found for composites containing PP‐MA having the highest molecular weight. The basal spacing of clay in the composites was measured by X‐ray diffraction (XRD). Nanoscale morphology of the samples was observed by transmission electron microscopy (TEM). The crystallization kinetics was measured by differential scanning calorimetry (DSC) and optical microscopy at a fixed crystallization temperature. Increasing the clay content in PP‐ MA330k/clay, a well‐dispersed two‐component system, caused the impact strength to decrease while the crystallization kinetics and the spherulite size remained almost the same. On the other hand, PP/PP‐MA330k/clay, an intercalated three‐component system containing some dispersed clay as well as the clay tactoids, showed a much smaller size of spherulites and a slight increase in impact strength with increasing the clay content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1562–1570, 2002