聚乙烯接枝改性及其与铝的粘结性

本文研究了聚乙烯／乙烯－醋酸乙烯共聚物（PE／EVA）和聚乙烯／乙烯－丙烯酸共聚物（PE／EAA）的共混物以及马来酸酐（MAH）接枝聚乙烯（MAH－g-PE)与铝箔的粘结性能,红外光谱证实反应产物为接枝产物,并考查了热复合工艺条件（温度,压力,时间）对剥离强度的影响,同时,发现在MAH－g-PE中加入10％的EVA可明显提高铝箔的粘结性,扩大了非极性聚乙烯的应用范围。     

聚乙烯接枝改性及其与铝的粘接性

本文研究了聚乙烯／乙烯－醋酸乙烯共聚物（PE／EVA）和聚乙烯／乙烯－丙烯酸共聚物（PE／EAA）的共混物以及马来酸酐（MAH）接枝聚乙烯（MAH－gPE)－－与箔的粘结性能。红外光谱证实反应产物为接枝产物。并考查了热复合工艺条件（温度、压力、时间）对剥离强度的影响。同时,发现在MAH－g－PE中加入10％的EVA可明显提高铝箔粘结性,扩大了非极性聚乙烯的应用范围。     

聚乙烯接枝改性及其与铝的粘接性

本文研究了聚乙烯／乙烯－醋酸乙烯共聚物和聚乙烯／乙烯－丙烯酸共聚物的共混物以及马来酸酐接枝聚乙烯中箔的粘结性能。红外光谱证实反应产物为接枝产物。并考查了热复合工艺条件对离强度的影响,同时,发现在ＭＡＨ－ｇ－ＰＥ中加入１０％的ＥＶＡ可明显提高铝箔的粘结性,扩大了非极性聚乙烯的应用范围。     

聚乙烯的化学改性——丙烯酸在聚乙烯上的接枝共聚及其表征

在二甲苯溶液中以过氧化苯甲酰为引发剂研究了丙烯酸在聚乙烯上的接枝共聚。讨论了反应温度、单体浓度和引发剂浓度对接枝率的影响。用红外光谱、ＸＰＳ、薄层色谱和接触角证实了接枝物的存在。又制备了接枝物钠盐。     

接枝聚乙烯改性聚碳酸酯

本文报道了采用接枝聚乙烯与聚碳酸酯共混改性的试验研究，并陈述了令人满意的结果。     

聚乙烯熔融接枝反应的研究

研究了接枝单体用量，引发剂品种及用量对聚乙接枝率的影响；接枝体系中加入含 化合物减少了接收过程中的凝胶；对接枝工艺的稳定性进行了考察；热处理法是除去接枝物中残留单体有效方法；研究了接枝物的结构与形态。     

聚乙烯蜡的微波辐射接枝反应研究

研究了聚乙烯蜡（ＰＥＷ）与马来酸酐（ＭＡＨ）的微波辐射接枝反应。考察了引发剂配比及种类、单体配比、辐射条件等对接枝反应的影响,通过正交实验应用多元线性拟合得出了酸值与接枝条件的经验式,制提了酸值为７５ｍｇＫＯＨ／ｇ左右的接枝聚乙烯蜡（ＭＰＥＷ）。ＩＲ、ＤＳＣ等测试结果表明,微波辐射确实能使ＰＥＷ与ＭＡＨ的接枝反应发生。     

聚乙烯固相接枝马来酸酐的研究

研究了以过氧化苯甲酰（ＢＰＯ）为引发剂,二甲苯为界面剂,粉状聚乙烯（ＨＤＰＥ、ＬＬＤＰＥ）固相接枝马来酸酐（ＭＡＨ）的反应。讨论了反应温度、引发剂用量、单体用量和界面剂种类等对接枝反应的影响,并用红外光谱法证实了接枝反应。结果表明,ＰＥ固相接枝ＭＡＨ反应对温度敏感,随温度升高,接枝率提高;在一定范围内,接枝率随引发剂用量、单体用量和搅拌转速、界面剂用量的增加而提高;界面剂用量虽少,但能促进ＢＰＯ、ＭＡＨ在ＰＥ上的反应。通过接枝反应可得到接枝率为９％左右的ＰＥ－ｇ－ＭＡＨ产物和接枝率为１３％以上的ＬＬＤＰＥ－ｇ－ＭＡＨ产物     

聚乙烯的化学接枝改性研究进展

综述了聚乙烯常用的化学接枝改性方法,接枝单体和引发剂的选择,讨论了接枝反应动力学,并简要阐述了接枝聚合物的结构性能。     

国内聚乙烯接枝和交联改性的研究进展

综述了国内聚乙烯接枝改性和交联改性技术的最新进展。     

Adhesion Between Hydrated Aluminium and Ethylene Copolymers Containing Methoxy Silane Groups

The peel strength between ethylene copolymers and aluminium has been investigated. The polymers were ordinary LDPE, copolymer with butyl acrylate (EBA), copolymer with vinyltrimethoxysilane (EVS), and copolymer with both comonomers (EVSBA). The aluminium was modified by hydration in boiling water up to 120 s. The strength of melt-pressed laminates was tested with a T-peel test and the failure mechanism was evaluated by FTIR and SEM. The hydration leads to a porous pseudoboehmite with an increased content of Al-OH groups, which causes considerable increases in peel strength for all polymers, in particular for EVS and EVSBA. The mode of failure varied between adhesive and cohesive depending on the surfaces. The introduced porosity contributes with mechanical keying while the Al-OH groups enable polar interactions for EBA and the formation of interfacial covalent bonds for EVS and EVSBA.     

Adhesion Between Hydrated Aluminium and Ethylene Copolymers Containing Methoxy Silane Groups

The peel strength between ethylene copolymers and aluminium has been investigated. The polymers were ordinary LDPE, copolymer with butyl acrylate (EBA), copolymer with vinyltrimethoxysilane (EVS), and copolymer with both comonomers (EVSBA). The aluminium was modified by hydration in boiling water up to 120 s. The strength of melt-pressed laminates was tested with a T-peel test and the failure mechanism was evaluated by FTIR and SEM. The hydration leads to a porous pseudoboehmite with an increased content of Al-OH groups, which causes considerable increases in peel strength for all polymers, in particular for EVS and EVSBA. The mode of failure varied between adhesive and cohesive depending on the surfaces. The introduced porosity contributes with mechanical keying while the Al-OH groups enable polar interactions for EBA and the formation of interfacial covalent bonds for EVS and EVSBA.     

Study on the morphology and properties of metallocene polyethylene and ethylene/vinyl acetate blends

Two commercial polymer materials, metallocene linear low density polyethylene (m‐LLDPE) and ethylene/vinyl acetate copolymer (EVA) have been used to form binary blends of various compositions. The mechanical properties, morphology, rheological behavior, dynamic mechanical properties, and crystallization of m‐LLDPE/EVA blends were investigated. It was found that with the addition of EVA, the fluidity and processability of m‐LLDPE were significantly improved, and the introduction of polar groups in this system showed no significant changes in mechanical properties at lower EVA content. As verified by morphology observation and differential scanning calorimetry analysis, miscible blends were formed within certain weight ratios. Dynamic mechanical property studies showed that flexibility of the blends was enhanced in comparion with pure m‐LLDPE, where the peak value of loss modulus shifted to lower temperature and its intensity was enhanced as EVA content increased, indicating the existence of more amorphous regions in the blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 905–910, 2004     

通信电缆用聚乙烯绝缘专用料的研制

研究了通信电缆用聚乙烯绝缘专用料的原料选用、工艺流程、加工性能及其影响因素。以HDPE为基础树脂。添加EVA、炭黑、抗氧剂、混炼剂、交联剂等。经熔融共混挤出造粒制得专用料。测试结果表明其各项性能均达到YD/T590.2-1992要求。     

Studies on Adhesion Between Natural Rubber and Polyethylene and the Role of Adhesion Promoters

Studies on adhesion between natural rubber (NR) and polyethylene (PE) with different levels of interaction (physical and chemical) have been carried out. Ethylene propylene diene rubber (EPDM) and chlorinated polyethylene (CPE) were used as physical promoters and epoxidised natural rubber/modified polyethylene (ENR/PEm) and sulfonated ethylene propylene diene rubber/modified polyethylene (S-EPDM/PEm) were used as chemical adhesion promoters. The failure surfaces were examined with the help of scanning electron microscopy (SEM), optical photography and electron spectroscopy for chemical analysis (ESCA) techniques.

The peel strength between natural rubber and polyethylene as measured in this study is 140 J/m². With the incorporation of physical promoters such as EPDM, the peel strength increases twenty fold because of structural similarity of EPDM with PE and the rubbery nature of EPDM. Similarly, the other promoters show significant improvement in peel strength. At high temperature and low rate of peeling, the nature of failure is mainly “stick-slip” for joints with interaction promoters. The average peel strength increases with increase in test rate and decrease in test temperature for most of the joints. All the data could be shifted onto a master curve indicating that the increase in strength is a result of viscoelastic dissipation. NR/EPDM/PE and NR/CPE/PE systems, however, behave in a different way probably because they alter the nature of crack propagation at or near the interface. ESCA results of the peeled PE surface show a chemical shift of C_1S peak. SEM photographs also indicate interaction at the interface when modifiers are used. An increase in crystallinity of PE from 30% to 64% and modulus increase the peel strength of NR/PE joints by a factor of four. The results of peel strength measurement at 90° are lower than those at 180°. Lap shear results are in line with peel strength.     

乙烯-醋酸乙烯酯共聚物对茂金属聚乙烯的改性研究

以添加不同比例的茂金属聚乙烯 (mLLDPE) /乙烯 醋酸乙烯酯 (EVA)共混物为研究对象 ,考察了EVA含量对mLLDPE/EVA共混物的力学性能、热性能、流变性能、动态力学性能和形态结构的影响。研究结果表明 ,EVA添加到mLLDPE中 ,增加了mLLDPE的剪切敏感度、降低了mLLDPE的熔融粘度、改善了mLLDPE的流动性和加工性 ;在一定的添加比例范围内mLLDPE和EVA具有很好的相容性 ,可以在改善mLLDPE加工性能、引入极性基团的同时又保持与纯mLLDPE相近的力学性能 ,但会导致共混物材料的刚性下降 ,柔性增加。热分析数据说明 ,mLLDPE/EVA共混体系中 ,在EVA含量较小时共混物存在大量共晶 ,与mLLDPE有很好的相容性 ,无论是熔融曲线还是降温曲线都只出现一个峰。当EVA含量增大时 ,mLLDPE/EVA共混物出现相分离 ,曲线出现双峰 ,但两峰值呈现靠近趋势 ,预示mLLDPE/EVA共混物中仍存在少量共结晶     

铸造用薄膜的开发与应用

介绍制备铸造用薄膜的选材要求,工艺条件,产品性能及应用。     

木质素填充LDPE、EVA对复合物性能的影响

以木质素为填充剂分别与低密度聚乙烯(LDPE)、乙烯-乙酸乙烯酯共聚物(EVA)共混,经双螺杆造粒机共混挤出造粒,再经吹塑成膜。研究了木质素/LDPE、木质素/EVA共混物薄膜的表面形貌、力学性能、热性能和红外光谱。热分析表明木质素与EVA共混物的热稳定性比木质素与LDPE的共混物热稳定性好;红外光谱分析表明木质素与EVA分子间产生了强烈的相互作用,扫描电镜分析表明木质素与EVA共混的相容性较好,力学性能分析表明低于30%的木质素与LDPE、EVA共混力学性能较好。     

超高相对分子质量聚乙烯纤维的表面改性研究

选择乙烯-醋酸乙烯酯共聚物作表面改性剂,将其溶解在二甲苯中,对超高相对分子质量聚乙烯(UHMWPE)冻胶纤维进行萃取,然后经过多级热拉伸制得改性UHMWPE纤维。对冻胶纤维的萃取动力学、改性前后纤维的表面化学结构、表面粘结性能和力学性能进行了比较。结果表明:加入表面改性剂后,冻胶纤维的萃取除油速率变慢;纤维与树脂基体的粘结强度大大提高;纤维的力学性能略有下降。     

EVA对HDPE光交联反应的影响

采用测定凝胶含量的方法,以二苯甲酮(BP)作为光引发剂、三羟甲基丙烷三丙烯酸酯(TMP-TA)为交联剂,研究了辐照时间、乙烯-醋酸乙酯共聚物(EVA)含量对EVA/HDPE复合材料光交联的影响,并且考察了光交联后EVA/HDPE复合材料的力学性能。研究结果表明,EVA的加入会显著改变体系的凝胶含量;而辐照时间对EVA/HDPE体系交联反应影响很大;体系的力学性能随着EVA含量的增加而变化。