共查询到19条相似文献,搜索用时 203 毫秒
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简单介绍了甲基丙烯酸缩水甘油酯熔融接枝聚烯烃的第二单体、引发剂、反应温度和反应时间等因素对接枝反应的影响,探讨了接枝率的测定方法及接枝聚烯烃在塑料改性中的应用等。 相似文献
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简单介绍了甲基丙烯酸缩水甘油酯(GMA)熔融接枝聚烯烃的第二单体、引发剂、反应温度和反应时间等因素对接枝反应的影响,接枝率的测定方法及接枝聚烯烃在塑料改性中的应用等。 相似文献
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综述了化学接枝改性聚丙烯(PP)的方法。通过水相悬浮接枝法改性PP,不仅能够保持PP原有的性能,还能增加一些新的优异性能。PP的接枝多采用自由基引发,通过引发剂分解产生的初级自由基在PP分子链上夺氢,从而形成PP大分子自由基。PP大分子自由基与接枝单体接触,引发单体聚合,形成接枝链,反应遵循自由基聚合。对于水相悬浮接枝而言,单体的亲水性会影响接枝率,此外,不同单体的反应活性也不相同,对接枝效果也有着根本性的影响,还有一些其他因素(如引发剂、反应时间和温度)也会对接枝率造成影响。化学接枝改性PP的方法简单、反应条件温和、PP降解程度低、反应易控制、产物后处理简单、相对环保,具有良好的发展前景。 相似文献
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热引发官能化HDPE、PP、EPDM及其增韧PA66研究 总被引:2,自引:0,他引:2
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。 相似文献
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甲基丙烯酸缩水甘油酯接枝聚烯烃的新进展 总被引:2,自引:0,他引:2
本文综述了甲基丙烯酸缩水甘油酯接枝聚烯烃的研究进展。包括常用的接枝方法,可能的接枝机理,接枝率的测定方法及接枝聚烯烃的应用等。 相似文献
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通过反应挤出的方式, 采用衣康酸及其衍生物对聚烯烃进行接枝改性, 可以显著改善材料性能, 特别是与其他高分子材料的相容性。本文从影响聚烯烃接枝改性的各个因素:聚烯烃类型、引发剂类型以及添加剂出发, 详细论述了国内外研究者的研究进展, 重点阐述了各个因素对聚烯烃改性机理、产物链结构的影响, 认为反应挤出接枝产物链段结构以及螺杆结构对反应挤出的影响这两方面值得进一步研究。 相似文献
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《Journal of Adhesion Science and Technology》2013,27(1-3):283-305
Plasma chemical methods are well suited for introducing functional groups to the surfaces of chemically inert polymers such as polyolefins. However, a broad variety of functional groups are often formed. Unfortunately, for further chemical processing such as grafting of molecules for advanced applications a highly dense monotype functionalized polyolefin surface is needed. Therefore, the main task was to develop a selective surface functionalization process, which formed preferably only a single type of functional groups at the surface in high concentration. Amongst the novel plasma methods, the underwater plasma process (UWP) is one of most attractive options to solve the problem of monotype functionalization. Such plasma is an efficient source of ions, electrons, UV-radiation, high-frequency shock waves, radicals such as hydroxyl radical, and reactive neutral molecules such as hydrogen peroxide. In contrast to established gas phase glow discharge processes, the water phase limits the particle and radiation energies and thus the energy input into the polymer. By virtue of the liquid water environment, which moderates highly energetic plasma species, extensive oxidation, degradation, cross-linking and radical formation on the polymer are more limited as compared to gas plasma exposure. The variety of plasma produced species in the water phase is also much smaller because of the limited reaction possibilities of the plasma with water. The possibility to admix a broad variety of chemical additives makes underwater plasma even more attractive. Hydrogen peroxide and the catalyst (Fe-ZSM5) should influence and increase the equilibrium concentration of OH radicals in the underwater plasma process. It was found that these radicals played a very important role in OH functionalization of polyolefin surfaces. Hydrogen peroxide was identified to be the most prominent precursor for OH group formation in the UWP. The catalyst would affect the steady state of OH radical formation and its reaction with the substrate surface and thus accelerates the functionalization process. 相似文献
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Achintya Kumar Sen Bibha Mukherjee A. S. Bhattacharya L. K. Sanghi P. P. De Anil K. Bhowmick 《应用聚合物科学杂志》1991,43(9):1673-1684
An attempt is made to develop a novel series of cable sheathing compounds with variation in chlorine content and sufficient fire retardance and unique low-smoke characteristics. These are prepared by blending PVC and functionalized polyolefins in different compositions. PE and EPDM have been functionalized by grafting dibutyl maleate (DBM) using DCP as initiator. FRLS compounds made from PVC-functionalized polyolefin blends possess the special characteristics of low-smoke, low-acid-gas generation, increased fire retardance, and improved volume resistivity, which are much better in comparison with a typical PVC sheathing compound. Thermoplastic elastomer (TPE) based nonhalogen FRLS compounds are also reported. The mechanisms for grafting, polymer-polymer and polymer-filler interactions have been presented. 相似文献
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表面光接枝主要是用芳酮引发有机材料产生自由基,从而引发单体聚合产生表面接枝链。表面光接枝应用领域广泛.可用于聚合材料的表面改性以及表面功能化。综述了紫外光引发接枝改性聚合物表面的研究进展,包括光接枝聚合机理、改性方法、影响因素等,并对其应用前景及研究方向进行了介绍。 相似文献
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聚烯烃接枝马来酸酐作为增容剂的应用 总被引:3,自引:0,他引:3
聚合物共混改性是制备新型高分子材料极为有交的方法,其中的关键是要解决各种聚合物之间一般相容性很差的问题,通常的解决办法是加入合适的增容剂,聚烯烃接枝马来酸酐(PO-g-MAH)是研究的很多的增容剂。制备聚烯烃接枝马来酸酐的方法有熔融法、溶液法、辐射法和固相法,其中最重要的方法是熔融法,笔者主要介绍了聚烯烃接枝马来酸酐作为增容剂在改性聚酰胺(PA6、PA66、PA12、PA1010)、聚酯(PET、PBT)、热塑性聚氨酯(TPU)等聚合物共混物,聚烯烃/无机填料,聚烯烃/有机纤维,复合增强材料,粘结剂等方面的应用,聚烯烃接枝马来酸酐与其它聚合物原位反应生成共聚物,一方面降低了表面张力,使得分散相在基体中分散得更好;另一方面增强了两相的粘合力,从而达到了增容的目的。 相似文献