三元乙丙橡胶接枝马来酸酐及其在尼龙6中的应用

分析了在含有适量聚丙烯(PP)的三元乙丙橡胶(EPDM)熔融接枝马来酸酐(MAH)反应体系中,引发剂过氧化二异丙苯(DCP)、MAH用量对产物接枝率和流变性能的影响,考察了二甲基苯胺(DMBA)、二甲基甲酰胺(DMF)、硫代二丙酸二月桂酯(DLTDP)3种阻交联剂对接枝反应体系的影响,并研究了尼龙6(PA6)/(EPDM/PP)-g-MAH共混物的微观结构与性能。结果表明:当DCP的质量分数为0·08%、MAH的质量分数为1·2%时,产物的接枝率可达到1·0%左右;在相同条件下,3种阻交联剂对产物的接枝率都有不同程度的降低,而加入DMBA最大程度地降低了体系的交联度;接枝物(EPDM/PP)-g-MAH以较小的粒径均匀分布在连续相PA6中;当(EPDM/PP)-g-MAH质量分数为15%~20%时,共混物发生由脆到韧的转变;当(EPDM/PP)-g-MAH质量分数为25%时,共混物的综合力学性能达到最佳;同时,接枝物的加入增大了共混物中PA6的结晶难度。     

粉状聚丙烯增韧增强研究

采用机械共混方法对粉状聚丙烯（PP）进行了增韧增强研究，探讨了增韧剂、增强剂和有少量自制的固相甲基丙烯酸（MAA）接枝粉状聚丙烯（PP-g-MAA)作增容剂存在下对粉状PP共混体系力学性能的影响，用热重分析法考察了改性粉状PP的热性能。结果表明，（乙烯／丙烯／二烯）共聚物（EPDM）／高密度聚乙烯（HDPE）为复合增韧剂，具有协同作用，可显著提高共混物的冲击强度：PP-g-MAA能明显改善PP／玻纤两相的界面结合力；PP／EPDM／HDPE玻璃纤维共混体系可以获得理想的增韧增强效果。     

热引发官能化HDPE、PP、EPDM及其增韧PA66研究

采用热引发熔融接技方法研究了不同反应条件下马来酸酐（MAH）接枝HDPE、接枝共聚PP及接枝EPDM弹性体的接枝反应。结果表明：本热引发接枝法可避免接枝过程中的交联副反应，制得具有较高接枝率（接枝率在0.3%以上），较好熔体流动性能，较少凝胶含量的马来酸酐接枝HDPE、接枝共聚PP及接枝EPDM。采用机械共混法对已官能化的聚烯烃弹性体和聚烯烃塑料分别和混合增韧PA66的情况进行了比较，结果显示：采用PA66／改性聚烯烃弹性体／改性聚烯烃塑料三元共混体系，可以在较少用量的改性橡胶条件下使PA66的缺口冲击强度达到原材料的10倍以上，并且材料弯曲模量损失减少。SEM对PA66／EPDM－g-MHA/PP-g-MAH三元共混体系脆韧转变的研究结果表明：体系分散相中的EPDM－g-MAH向PA66基体扩散、渗透或形成嵌段共聚物的部分是增韧PA66中的有效成分。     

PP熔体接枝物改善HPVC/PP共混物的相容性

采用PP熔体接枝物改善HPVC/PP共混物的相容性。考察了共混比、不饱和极性单体、PP熔体挤出接枝物、增塑剂及EPDM用量对共混物力学性能的影响。     

PP／PE复合基材及其增韧研究

研究了PP/PE共混复合基材的力学性能和形态结构与组成配比的关系.结果表明,PP/HDPE/EPDM和PP/LLDPE共混体系可以制成具有高抗冲击性能的复合基材,且其他力学性能均衡,加工性能良好。弹性体SRS对复合基材的力学性能及形态有较大影响.实验结果表明,LLDPE具有分割、插入、细化PP球晶的作用,并与PP有较好的相容性;EPDM对PP/HDPE共混体系具有良好的增容效果。     

接枝共混物和PBT对SEBS/PP体系的复合作用

研究了马来酸酐接枝聚乙烯、乙烯-醋酸乙烯酯共混物,聚对苯二甲酸丁二醇酯(PBT)二者对苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)/聚丙烯(PP)体系的复合作用;通过扫描电子显微镜、微机控制电子万能试验机分析了材料的显微组织形貌,测试了材料的力学性能,并用一组验证试验证明了复合作用的存在。结果表明,接枝共混物和PBT二者对SEBS/PP体系产生了一种复合作用,这种复合作用能显著提高SEBS/PP体系的拉伸性能,当接枝共混物、PBT各占体系的10%时,拉伸性能最佳。     

EPDM与EA接枝共聚反应

以BPO为引发剂,二甲苯为溶剂,在EPDM上接枝丙烯酸乙酯(EA)红外光谱分析与溶解实验证明了接枝物的存在;接触角实验证明,接枝后EPDM的极性加大;皂化水解接枝物后,用化学滴定法测定了接枝物的接枝率。讨论了单体浓度、引发剂浓度及反应温度对接枝率的影响,也研究了氧对此反应体系的影响,并计算了此接枝反应体系的接枝反应活化能。     

新型PP接枝物的制备及应用

为制备可涂装良好力学性能的共混材料，利用复合引发体系，双组分熔融接枝法，研制开发了新型聚丙烯接枝物，讨论了复合引发体系共聚单体在接枝过程中的作用，研究了接枝物对ＰＰ／无机填充物的相容性的影响。结果发现：接枝物能有效地提高ＰＰ／无机填充物的相容性。将少量接枝物与ＰＰ／无机填充物、ＨＤＰＥ、橡胶共混，并添加相容剂及其他助剂，可得到良好力学性能、优良可涂装性能的材料，其性能达到国外同类产品指标要求。     

PP/POE/纳米CaCO_3复合材料的改性

对三元复合体系聚丙烯(PP) /聚烯烃弹性体(POE) /纳米CaCO3进行了改性研究,主要探讨了马来酸酐接枝聚丙烯(PP g MAH)、乙烯 醋酸乙烯共聚物(EVA)、均聚聚丙烯(PPH)等聚合物对该复合体系性能的影响。研究结果表明,加入适量的接枝物有利于三元复合材料强度的提高,在特定的配比下,PPH和PP3 (共聚聚丙烯 )可分别作为该复合体系的熔体流动速率调节剂和增韧剂。     

PP-g-MAH对PP/PA6共混物的增容作用

采用熔融接枝法,考察了单体和引发剂用量对聚丙烯(PP)/马来酸酐(MAH)接枝物接枝率的影响。将PP-g-MAH作为PP/尼龙6(PA6)共混物的增容剂,并利用SEM、XRD、DSC-TGA和万能试验机等测试手段对PP-g-MAH增容改性PP/PA6共混体系进行了研究。结果表明,PP-g-MAH接枝物对PP/PA6共混物具有良好的增容效果,PP结晶得到细化,共混物的力学性能和耐高温性能得到改善。     

Melt grafting of vinyltrimethoxysilane and water crosslinking of polypropylene/ethylene-propylene diene terpolymer blends

The melt grafting of vinyltrimethoxysilane (VTMS) onto polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM) blends was studied. The effect of VTMS, EPDM and initiator concentrations on mechanical properties, melt flow index (MFI) and gel content of the modified PP/EPDM samples were investigated. The influence of coagents, i.e. styrene and trimethylolpropane trimethacrylate was also studied. Scanning electron microscopy (SEM) was used to observe the fractured surface of PP/EPDM and the modified PP/EPDM blends. The VTMS grafting reaction was in situ monitored using differential scanning calorimetry (DSC). Moreover, the thermal and crystallization behavior of VTMS-crosslinked PP/EPDM blends were studied by thermogravimetric analysis (TG) and DSC, respectively. It had been found that the thermal stability of VTMS-crosslinked PP/EPDM was improved. DSC measurements showed that the grafting reaction occurs from 170 to 220 °C and the crystallization temperatures increased compared with those of the untreated PP/EPDM.     

PP/HDPE/EPDM复合体系微孔发泡实验

聚丙烯(PP)是结晶性聚合物,熔体强度低,发泡性能差.为了提高PP的微孔发泡性能,首先将PP和聚乙烯(PE)共混,然后在PP/PE共混体系中加入少量EPDM,研究EPDM的质量含量对PP/PE共混体系熔体强度和最终泡孔结构的影响.分析机理,寻找能够提高PP熔体强度和改善发泡性能的材料.     

EPDM/PP的接枝改性及在超韧尼龙中的应用研究

研究了引发剂、接枝单体用量及阻交联剂品种对含有聚丙烯的三元乙丙橡胶熔融接枝马来酸酐接枝率的影响。结果表明:引发剂的含量是获取高接枝率的关键,当过氧化二异丙苯的加入量为0.08%,马来酸酐的用量为1.2%时,体系的接枝率在1%左右。并讨论了接枝物在超韧尼龙合金中的应用。     

Structure and properties of dynamically cured EPDM/PP blends

The structure and properties of polyolefin blends of ethylene–propylene–diene terpolymer (EPDM) and polypropylene were studied. Blends were prepared in a laboratory internal mixer where EPDM was cured with PP under shear with dicumyl peroxide (DCP) at different shear conditions (blend–cure). Blends were also prepared for comparison from EPDM which were dynamically cured in the absence of PP and blended later (cure–blend). The effect of DCP concentration, intensity of the shear mixing, and rubber/plastic composition were studied. In blend–cure, the melt viscosity increased with increasing DCP concentration in blends of 75% EPDM and 25% PP, but it decreased with increasing DCP concentration in blends of 75% PP and 25% EPDM. In cure–blend, however, the melt viscosity increased with increasing DCP concentration for all compositions. The melt viscosity decreased with increasing intensity of the shear mixing presumably due to the formation of the smaller segregated microdomain of the crosslinked EPDM gels in both blend–cure and cure–blend materials. The crystallization rate was higher in EPDM/PP blends than in PP homopolymer. The crystallization rates for various blending conditions were also compared.     

共混时间对反应性PP／EPDM合金性能的影响

通过凝胶含量测定、力学性能试验以及熔体流动性能测试等手段,研究了共混(反应)时间对密炼法和挤出法反应性PP/EPDM共混合金性能的影响及其机理。结果显示,适当延长共混(反应)时间不仅能提高合金中EPDM的交联程度,而且还能使交联EPDM颗粒粒径变小、粒度均匀、在PP连续相中的分布均匀性增加,从而有效地提高该合金的增韧效果及其他力学性能,提高合金的加工流动性。     

Effect of the viscosity and processing parameters on the surface resistivity of polypropylene/multiwalled carbon nanotube and ethylene–propylene–diene/multiwalled carbon nanotube nanocomposites

In this study, relatively large amounts of polypropylene (PP) and ethylene–propylene–diene (EPDM) were melt‐mixed with multiwalled carbon nanotubes (MWCNTs). Although the melt‐compounding method has many advantages, the uniform dispersion of carbon nanotubes in the polymer matrix is still the most challenging task. Because the electrical conductivity of composites is strongly influenced by the filler's state of dispersion and the extent of filler breakage during processing, the effects of the viscosity and processing conditions, such as the mixing time, rotor speed, and cooling rate, on the surface resistivity were studied. The PP/MWCNT nanocomposites displayed a high dependence of surface resistivity on the cooling rate, and the EPDM/MWCNT nanocomposites displayed a higher surface resistivity at the same content of MWCNTs and less dependence of surface resistivity on the cooling rate compared with PP/MWCNT nanocomposites. The increased surface resistivity of the EPDM/MWCNT nanocomposites was observed when EPDM with higher viscosity was used to prepare the EPDM/MWCNT nanocomposites. By increasing the rotor speed, lower surface resistivity was obtained in the PP/MWCNT nanocomposites. However, by increasing the rotor speed, a higher surface resistivity was obtained in the EPDM/MWCNT nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

EPDM/PP共混物老化性能的研究

研究了三元乙丙橡胶改性聚丙炮共混物的性能,探讨了不同含量的ＥＰＤＭ对共混物的力学性能,热性能、流变性能的影响,还探讨了不同品种,不同含量的抗氧剂对共混物耐老性影响。     

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.     

高韧性和高流动性PP／EPDM共混材料的研制

研究了乙丙橡胶的门尼粘度和结晶性对聚丙烯增韧效果的影响，结果表明，高门尼粘度，部分结晶性橡胶在获得较好韧性的同时不保持较高的刚性，但流动性较差，通过加入ＨＤＰＥ能在复合增韧的同时提高共混物的流动性，添加少量油酸酰胺和硬脂酰胺敢能适当提高共混物的流动性，采用过氧化物降解聚丙烯可以显著提高共混物的流动性，但韧性明显下降，采用可控降解和动态硫化相结合的技术是在得到高韧性，高流动性共混ＰＰ的有效途径。