Glass-fiber-reinforced polypropylene/EPDM blend. I. Melt rheological properties

Melt rheological properties of the blend of isotactic polypropylene (PP) and ethylene propylene diene rubber (EPDM) at varying ratios and of the glass fiber (GF) filled PP and PP/EPDM blend by varying both GF loading and blending ratio of the polyblend matrix are studied. Rheological measurements at 220°C in shear rate range 10¹?10⁴s^?1 were made on a capillary rheometer. Scanning electron micrographs of the extrudates are presented to show the morphology and the alignment of the glass fibers with respect to the flow direction. Variations of pseudoplasticity index, melt viscosity, and melt elasticity with EPDM content in PP/EPDM blend, and with varying GF content at any given composition of the matrix in PP/EPDM/GF ternary system, in the studied range are presented and discussed. Resultes on melt viscosity and melt elasticity show (i) reduced effect of GF at high shear rates on these properties and (ii) upward deviation of melt viscosity versus shear rate curve at low shear rates. A change in flow behavior in presence of GF is observed around a critical shear rate 2 × 10³ s^?1 and is attributed to the difference of interaction of GF and the dispersed rubber droplets at high and low shear rates. Elastic recovery showed nonequilibrium behavior at low shear rates.     

Synergetic toughness and morphology of poly(propylene)/nylon 11/maleated ethylene‐propylene diene copolymer blends

Polypropylene (PP)/nylon 11/maleated ethylene‐propylene‐diene rubber (EPDM‐g‐MAH) ternary polymer blends were prepared via melt blending in a corotating twin‐screw extruder. The effect of nylon 11 and EPDM‐g‐MAH on the phase morphology and mechanical properties was investigated. Scanning electron microscopy observation revealed that there was apparent phase separation for PP/EPDM‐g‐MAH binary blends at the level of 10 wt % maleated elastomer. For the PP/nylon 11/EPDM‐g‐MAH ternary blends, the dispersed phase morphology of the maleated elastomer was hardly affected by the addition of nylon 11, whereas the reduced dispersed phase domains of nylon 11 were observed with the increasing maleated elastomer loading. Furthermore, a core‐shell structure, in which nylon 11 as a rigid core was surrounded by a soft EPDM‐g‐MAH shell, was formed in the case of 10 wt % nylon 11 and higher EPDM‐g‐MAH concentration. In general, the results of mechanical property measurement showed that the ternary blends exhibited inferior tensile strength in comparison with the PP matrix, but superior toughness. Especially low‐temperature impact strength was obtained. The toughening mechanism was discussed with reference to the phase morphology. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Interfacial adhesion through maleic anhydride grafting of EPDM in PP/EPDM blend

This paper presents a study of interface modification effect through the use of maleic anhydride (MAH) grafting on one of the component polymers of the binary blend. The system used is binary blend of polypropylene (PP) and the elastomer EPDM (copolymer of ethylene–propylene–diene monomer). Two sets of the blend (i) PP/EPDM binary blend and (ii) PP/EPDM‐g‐MAH binary blend at constant degree of grafting (i.e., EPDM : MAH ratio) and at varying blending ratios were studied and compared for the properties and structure development. Results are discussed to illustrate the effect of interfacial modification due to presence of MAH by comparing the data of mechanical properties and crystallization behavior for the two sets of the binary blend at identical blending ratios, as well as to study the trends of variation of properties with blending ratio for each individual set of the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5528–5532, 2006     

Largely improved toughness of PP/EPDM blends by adding nano-SiO2 particles

As a part of long-term project aimed at super polyolefin blends, in this work, we report the toughness and phase morphology of polypropylene (PP)/EPDM/SiO₂ ternary composites. Two processing methods were employed to prepare PP/elastomer/filler ternary composites. One was called one-step processing method, in which the elastomer and the filler directly melt blended with PP matrix. Another one was called two-step processing method, in which the elastomer and the filler were mixed first, and then melt blended with pure PP. Two kinds of PP (grafted without or with maleic anhydride (PP-g-MA)) and SiO₂ (treated with or without coupling agent) were used to control the interfacial interaction among the components. The dependence of the phase morphology on interfacial interaction and processing method was investigated. It was found that the formation of filler-network structure could be a key for a simultaneous enhancement of toughness and modulus of PP and its formation seemed to be dependent on the work of adhesion (W_AB) and processing method. As the W_AB of PP/EPDM interface was much lower than that of PP/SiO₂ and EPDM/SiO₂, and the two-step processing method was used, the formation of filler-network structure was favorable. In this case, a super toughened PP ternary composite with the Izod impact strength 2-3 times higher than PP/EPDM binary blend and 15-20 times higher than pure PP could be achieved.     

EPDM/聚烯烃共混型热塑性弹性体的研究

制备ＥＰＤＭ／聚烯烃简单共混型热塑性弹性体。研究了聚合物种类、橡塑比、二元和三元共混对共混物力学性能的影响。结果表明，部分结晶性ＥＰＤＭ共混物的力学性能比无定形ＥＰＤＭ共混物好，部分结晶性ＥＰＤＭ与ＬＤＰＥ（低密度聚乙烯）共混物的拉伸强度大于两者的加和值，而其它二元共混物的拉伸强度均低于两共混单元的加和值；用ＬＤＰＥ部分替代ＰＰ，或用氯磺化聚乙烯（ＣＳＭ）部分替代结晶性ＥＰＤＭ进行三元共混，能改善部分结晶性ＥＰＤＭ／ＰＰ共混物的某些性能。     

EPDM/纳米CaCO3预混料动态力学性能及其对聚丙烯基三元复合材料韧性的影响

采用熔融法分别制备了三元乙丙橡胶(EPDM) /纳米碳酸钙（CaCO3）二元预混料及其与聚丙烯（PP）共混的三元复合材料。利用动态力学分析仪研究了纳米CaCO3含量和共混时间对EPDM /纳米CaCO3二元预混料的动态力学性能的影响,利用扫描电子显微镜分析了分散相纳米CaCO3和EPDM在PP基体中的形态。结果表明,常温下,纳米CaCO3含量为70 %（质量分数,下同）、共混时间为15 min时,EPDM/纳米CaCO3二元预混料的储能模量、损耗模量和损耗角正切达到最高值;纳米CaCO3与EPDM组成的二元共混物分散于PP基体中,通过纳米CaCO3团聚体及EPDM协同变形、界面脱黏成纤及诱导剪切带的形成耗散外界作用能,显著提高了PP/EPDM/纳米CaCO3三元复合材料的冲击强度。     

PP/EPDM/纳米弹性体粒子三元共混体系的脆韧转变

研究了PP／EPDM／纳米弹性体粒子(ENP)三元共混体系的脆韧转变行为。结果表明，与PP／EPDM二元共混物相比，三元共混物的脆韧转变可以在EPDM质量分数较低的情况下发生；在橡胶总质量分数相同的情况下，三元共混物有更高的冲击强度，拉伸强度有一定提高。从脆断样条的扫描电镜照片观察到，在相同EPDM质量分数下，PP／EPDM／ENP三元共混物中的EPDM粒子明显细化，分布均一，粒子间距减小，这是脆韧转变提前的原因。     

PP/橡胶合金热致变色原因的探讨

采用熔融共混法制备了几种聚丙烯(PP)/橡胶合金,并用沸水进行浸泡。结果发现,PP/三元乙丙橡胶(EPDM)合金与PP/聚烯烃热塑性弹性体(POE)合金热水浸泡时发生变色,而PP/乙丙橡胶(EPR)合金不变色。采用X射线衍射仪(XRD)、差示扫描量热仪(DSC)对PP/橡胶合金的热致变色原因进行探讨。结果表明:热水浸泡时PP发生二次结晶是热致变色的主要原因。     

Blends of i‐PP and SBS. I. Influence of the in situ compatibilization on the morphology

This article concerns the in situ compatibilization of immiscible isotactic polypropylene/butadiene‐styrene‐butadiene triblock copolymer blends (i‐PP/SBS) by means of a reactive mixture. For this purpose, maleated PP (PP‐MAH) and SBS (SBS‐MAH) were used as functionalized polymers and 4,4′‐diaminediphenylmethane was used as a coupling agent between maleated polymers, resulting in a graft copolymer. Binary blends i‐PP/SBS, nonreactive ternary blends i‐PP/PP‐MAH/SBS, and reactive ternary blends i‐PP/PP‐MAH/SBS‐MAH with varying diamine and anhydride molar ratios were prepared. Torque measurements suggest a graft copolymerization during the melt blending for ternary reactive blends, but the extension of the grafting does not vary with the diamine and anhydride molar ratio, but with the elastomer concentration. The morphology of the blends was investigated by scanning electron microscopy. The morphology of binary and ternary nonreactive blends is similar, exhibiting elastomer domains disperse in the i‐PP matrix, whose sizes increase with elastomer concentration. On the other hand, the elastomer domain size in the ternary reactive blends is practically independent of the blends composition and of the diamine and anhydride molar ratio. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 847–855, 2002     

Polymer encapsulation of glass filler in ternary PP/PA-6/glass blends

The morphology and rheology of ternary isotactic polypropylene (PP)/polyamide-6 (PA-6)/glass blends is investigated and contrasted with the behavior of two-component (binary) PP/PA-6 blends. Injection molded samples of binary blends exhibit an interlayer slip morphology for both PP and PA-6 as the matrix and the blend shear viscosity is lower than expected from a rule of mixtures. The morphology of ternary blends is dependent on the choice of the matrix phase. In ternary blends with a PA-6 matrix, the PP domains and glass fibers are separately dispersed within the matrix. In ternary blends with a PP matrix, the PA-6 is mainly found surrounding (encapsulating) the glass fibers, and the extent of the interlayer slip morphology is reduced. Variations in glass surface treatment, blending time, and order of addition did not affect the rapid encapsulation of glass by the PA-6. A reduction in blending temperature, below the peak PA-6 melting temperature, hinders encapsulation.     

剪切速率对动态硫化PP/EPDM热塑性弹性体相态结构及性能的影响

采用动态硫化法,在双螺杆挤出机中制备以聚丙烯(PP)/三元乙丙橡胶(EPDM)为基体材料的热塑性弹性体,研究螺杆转速对PP/EPDM热塑性弹性体相态结构及性能的影响;采用差示扫描量热(DSC)仪分析了PP/EPDM热塑性弹性体的结晶性能,通过扫描电子显微镜(SEM)分析PP/EPDM热塑性弹性体的微观相态结构,并用万能试验机等对其力学性能进行测试。结果表明,随着螺杆转速的增加,PP/EPDM热塑性弹性体的结晶温度降低,凝胶含量、拉伸强度和断裂伸长率先增大后减小,压缩永久变形先减小后增大,而螺杆转速对硬度的影响不明显。当螺杆转速为180 r/min时,PP/EPDM热塑性弹性体的凝胶含量、拉伸强度和断裂伸长率均达到最大值,分别为56.8%,15.9 MPa和634%,压缩永久变形和硬度(邵A)均达到最小值,分别为68.8%,88。     

The effect of viscosity of polyethylene on the evolution of phase structure during the mixing of polypropylene/EPDM elastomer/polyethylene blends

The dependences of phase structure and notch impact strength on conditions of mixing have been compared for the binary blend PP/EPDM and for two ternary blends PP/EPDM/PE possessing different viscosities of polyethylene. At low rates and short times of mixing a phase structure with pronounced inhomogeneities (particles of the dispersed phase having diameters of tens μm) is formed in all blends. Conditions of mixing needed for the formation of a homogeneous phase structure (with particles having diameters of several μm) depend on the average viscosity of the components forming the inclusions (EPDM elastomer or EPDM elastomer/polyethylene). Depending on the conditions of mixing and on the rheological properties of components, substitution of one part of the EPDM elastomer with PE may lead to an increase or decrease in the impact strength of the final blend.     

动态全硫化EPDM／PP共混型热塑性弹性体制备工艺研究

对ＥＰＤＭ／ＰＰ 共混型热塑性弹性体的产生和发展,作了简单回顾,介绍了动态全硫化ＥＰＤＭ／ＰＰ 共混型热塑性弹性体的制备原则,重点讨论了这类热塑性弹性体的制备工艺。     

SIS/SBS/PP共混改性的研究

研究了新型聚丙烯(PP)合金材料的配方、制备、工艺及性能。分别讨论了不同用量的三元乙丙橡胶 (EPDM)、苯乙烯与异戊二烯嵌段共聚物(SIS)及苯乙烯与丁二烯嵌段共聚物(SBS)与PP组成的二元和三元共混体系对材料力学性能的影响。结果表明:SIS为PP较好的增韧剂,PP／SIS/SBS三元共混体系具有较好的协同效应,在某种程度上可以代替EPDM改性PP,共混改性后拉伸强度、扯断伸长率等性能优良。     

粘土与弹性体改性聚丙烯复合材料的流变性研究

采用熔融共混法制备了二元复合材料聚丙烯(PP)／有机粘土(OREC)体系(PR体系)、聚烯烃弹性体(POE)增韧的PP体系(P厄体系)及三元复合材料OREC、POE补强增韧的PRE体系，采用毛细管流变仪研究了两种聚合物复合材料的流变性能。结果表明，在所研究的范围内PP及PP复合材料体系熔体的流变性均属于假塑性流体；对二元体系，OREC能够大大改善PP体系的加工流动性，在相同条件下PR体系的粘度小于纯PP的粘度，且随着粘土添加量的增加，粘度的下降幅度增大；POE能够改善PP的加工性能；三元PRE体系在相同条件下的表观粘度随着POE用量的增加而减小，但只有在较大用量及较小剪切力下的表观粘度小于二元体系的表观粘度。     

Processing of polyolefin blends

The morphology of binary and ternary polyolefin blends of polypropylene (PP), ethylene-propylene-diene terpolymer (EPDM) and polyethylene (PE) following processing by injection and compression molding has been examined by optical and scanning electron microscopy. Internal surfaces were generated by low temperature fracture and etching with cyclohexane. In binary blends, droplets of EPDM are elongated in the flow direction within 400μm of the mold surface in injection molding, yielding a skin region which is distinct from an isotropic core containing spherical EPDM inclusions. Spherical droplets of EPDM or PE in binary blends with PP increase in size with increasing compression molding time. In ternary blends, spherical inclusions containing both EPDM and PE are dispersed in PP. With increasing compression molding time, EPDM separates from PE and concentrates at the outer edges of the PE inclusion, effectively isolating PE from the PP matrix.     

Morphology and properties of PP/EPDM binary blends and PP/EPDM/nano‐CaCO3 ternary blends

In this article, the morphology, crystallization, and rheological behaviors of polypropylene (PP)/ethylene‐propylene‐diene terpolymer (EPDM) binary blend and PP/EPDM/calcium carbonate nanoparticles (nano‐CaCO₃) ternary blend were investigated. Two processing methods, i.e., direct extrusion and two‐step extrusion, were employed to prepare the PP/EPDM/CaCO₃ blend. The influence of EPDM and nano‐CaCO₃ respectively on phase morphology and properties of PP/EPDM blend and PP/EPDM/CaCO₃ blend were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic rheometer. The crystallinity and crystallization temperature of PP/EPDM blend were improved in comparison to pure PP due to addition of EPDM, but kept invariable with the increased EPDM loading. As the EPDM content was increased, the mobility of PP molecular chains was weakened. Compared with direct extruded blend, less and finer nano‐CaCO₃ was dispersed in matrix of two‐step extruded blend. Accordingly, the increased nano‐CaCO₃ in matrix gave rise to a weaker increment in crystallinity and crystallization temperature of two‐step extruded blend, and a later platform of tanδ curve. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

载体包裹填料提高PE/PP/EPDM/BN材料导热性

以三元乙丙橡胶(EPDM)/氮化硼(BN)复合材料为母料,通过熔融共混EPDM/BN复合材料与聚乙烯(PE)、聚丙烯(PP),制备PE/PP/EPDM/BN复合材料。采用PE∶PP的比例为5∶5,以使复合材料形成共连续结构;通过EPDM包裹BN的方法,实现BN在PE/PP/EPDM/BN复合材料共连续结构的相界面处分布,以形成导热通路,从而提高PE/PP/EPDM/BN复合材料的导热性能。通过接触角测试和扩散系数公式计算预测了EPDM会选择性分布在PE/PP/EPDM复合材料共连续结构的相界面处。通过连续度计算结果得出,EPDM为PE和PP总质量的15%时,EPDM的连续度为85.3%。由扫描电子显微镜分析表明EPDM在PE/PP/EPDM/BN复合材料中连续贯通。由导热测试分析知,随着BN含量的增加,PE/PP/EPDM/BN复合材料的热导率逐渐增加。这项研究提高了PE/PP复合材料的热导率,此材料在电子工业中可能具有潜在应用。     

动态硫化PP/EPDM热塑性弹性体的研究进展

阐述了动态硫化聚丙烯(PP)/三元乙丙橡胶(EPDM)共混型热塑性弹性体的发展历史和发展状况;概述了动态硫化PP/EPDM共混型热塑性弹性体的硫化体系及硫化原理;总结了共混体系的成份配置和工艺条件对PP/EPDM共混物性能和结构的影响;简述了动态硫化PP/EPDM热塑性弹性体的研究现状与应用;最后展望了动态硫化PP/EPDM热塑性弹性体的发展趋势。