辐射交联热收缩聚乙烯的研究进展

介绍了辐射交联热收缩聚乙烯的研究现状，分析了热收缩机理以及辐射交联规律，重点讨论了辐射交联热收缩聚乙烯的制备工艺以及聚乙烯和乙烯醋酸乙烯共聚物、聚氨酯、氯丁橡胶等共混体系的研究，并分析了辐射交联热收缩聚乙烯的未来研究发展方向。     

电子束辐照对乙烯-甲基丙烯酸甲酯共聚物/三元乙丙橡胶共混体系性能的影响

通过电子束辐照研究了乙烯-甲基丙烯酸甲酯共聚物（EMMA）与三元乙丙橡胶（EPDM）不同共混比例材料的力学性能、硬度、交联度、结晶及形状记忆等,考察了辐照剂量和共混组分比例对材料性能的影响。结果表明,辐照提高了共混体系的力学性能和硬度,同时降低了结晶性能,这主要是由于辐照诱发了交联反应,使材料内部产生了交联结构。辐照交联为EMMA/EPDM共混物热收缩材料提供了形状回复的驱动力,但降低了形状固定率,通过控制交联度和结晶相所占比例,能够得到综合性能好的热收缩材料。当EMMA/EPDM（质量比）达到或高于3/7、辐照剂量控制在40~80 k Gy时,能够制备出满足基本要求的热收缩材料。     

辐射产强PP／TAIC（TMPTMA）／PE共混体系相界面反应的研究：（Ⅰ）多官能…

本研究中采用三烯丙基异腈脲酸酯和三羟甲基丙烷三甲基丙烯酸酯为ＰＰ／ＰＥ共混体系的多官能团单体。研究了辐照剂量，多官能团单体种类和多官能团单体用量对共混物形态结构及力学性能的影响。发现ＴＡＩＣ及ＴＭＰＴＭＡ对ＰＰ／ＰＥ体系有较好的增容作用，共混物具有好的相容性，力学性能得到改善。     

动态硫化EPDM／PP热塑性弹性体的流变性能

研究了共混工艺条件，橡塑比，橡胶相交联速率及交联密度，ＰＰ的熔体流动指数对ＥＰＤＭ／ＰＰ共混物流变性能的影响。结果表明，当降低ＥＰＤＭ含量，减小ＥＰＤＭ相粒径时，共混物的流动性增强。共混物发生熔体破裂是由于ＥＰＤＭ和ＰＰ相在挤出后两相大分子的弛豫行为不同所致。提高ＰＰ含量，降低了ＥＰＤＭ相粒径，同时ＥＰＤＭ分散相具有适宜的交联密度时，可以得到挤出表面光滑的共混物。     

二次辐照对交联聚乙烯结构和性能的影响及其应用

研究了辐照对高密度聚乙烯(HDPE)、低密度聚乙烯(LDPE)、线型低密度聚乙烯(LLDPE)、乙烯-乙酸乙烯酯共聚物(EVA)及其共混物性能的影响。将辐照交联后的聚合物经扩张定型后再次辐照,考察了二次辐照对交联结构的影响,并利用二次辐照法制备了一种新型热收缩套管产品。结果表明:随着辐照剂量的增加,样品的凝胶含量增大,拉伸强度先增大后减小,而断裂伸长率则逐渐降低;二次辐照后,样品的形变回复率随着辐照剂量的增加显著降低;所制备的热收缩套管两端收缩率大、中间部分收缩率小,实现了同一制品不同部位收缩倍率的可控性,具有良好的应用前景。     

热缩型硅橡胶复合绝缘子的研制

研究了乙烯醋酸乙烯共聚物（EVA）、硅橡胶（PDMVS）和氢氧化铝不同配比时所组成的共混物的力学性能和电学性能及辐射交联对EVA／KPDMVS共混物的凝胶含量和力学性能的影响规律，确定了适合的辐交联剂量及利用该共混物制备热缩型硅橡胶复合绝缘子的工艺条件。     

SBS/CPE共混物辐射效应研究

研究了不同辐照剂量下苯乙烯-丁二烯-苯乙烯嵌段聚合物（SBS）／氯化聚乙烯（CPE）共混物的动态流变性能及力学性能。结果表明：随着辐照剂量的增大，共混物的粘流活化能降低，温度敏感性减弱；共混物拉伸强度和断裂伸长率下降，凝胶含量增加。     

PVC／SBS／CPE共混体系力学性能研究

以ＣＰＥ为第三组分，制备了不同ＣＰＥ含量的ＰＶＣ／ＳＢＳ／ＣＰＥ三元共混物，使用冲击实验机和电子万能实验机测定了系列样品的力学性能，结果表明：ＣＰＥ的加入对ＰＶＣ／ＳＢＳ二元共混物的力学性能有一定程度的改善，当ＣＰＥ含量为１５－２０份时，效果最佳 。     

辐射交联高发泡聚乙烯泡沫的制备及应用

利用辐射交联技术制备了高发泡的聚乙烯（ＰＥ）泡沫。研究了辐射剂量，发泡剂用量、发发泡时间对发泡倍率的影响。结果表明，辐照剂量为３０ＫＧｙ，发泡温度为２００℃，发泡时间为２ｍｉｎ时能够制备发泡倍率为３０倍的ＰＥ泡沫。     

辐射增强相界面反应改善PP／PE共混体系相间粘结的研究

采用三烯丙在异腈脲酸酯（ＴＡＩＣ）为多官能团单体,研究了ＰＰ／ＰＥ／ＴＡＩＣ共混体系的辐射增强相界面反应。应用ＳＥＭ、ＤＳＣ、ＤＤＶ对共混体系的形态结构和相容性进行了表征。结果表明,在ＰＰ／ＰＥ共混物中加入ＴＡＩＣ后,经＾６０Ｃｏγ射线辐照可以增强ＰＰ／ＰＥ共混物的相间粘结,共混物具有好的相容性,力学性能得到改善。     

Features of the Structure and Properties of Radiation Vulcanizates Based on Blends of Polybutadiene and Ethylene‐Propylene Diene Rubber

Polybutadiene rubber (BR) was blended with ethylene‐propylene diene (EPDM) rubber on rubber mill with different weight ratios (100/0‐70/30‐50/50‐30/70‐0‐100), then application of gamma rays at different irradiation doses from 25 up to 150 kGy to induce crosslinking. Mechanical, physio‐chemical, and characterization of prepared blends are to be followed up as functions of the blend composition and the radiation absorbed dose. Mechanical properties like tensile strength (TS), elongation at break (E_b), and tensile modulus (M₁₀₀) were increased with increasing content of EPDM in blend composition. On the other hand, TS and M₁₀₀ increased with radiation dose, whereas the value of E_b decreased with radiation dose. Physico‐chemical properties like gel fraction and volume fraction of rubber in swollen gel (V_r) increased with increasing the content of EPDM rubber in blend formulation while the swelling ratio and soluble fraction decreased with increasing content of EPDM. On the other hand, the V_r increased with radiation dose, whereas the values of soluble fraction and selling ratio (Q) decreased with radiation dose. Fourier transforms‐infrared measurements confirmed the compatibility between BR and EPDM rubber moieties in the blend matrix. J. VINYL ADDIT. TECHNOL., 25:E64–E72, 2019. © 2018 Society of Plastics Engineers     

Thermal and physicomechanical properties of gamma‐irradiated EPDM/waste newsprint microfibers composites treated using acrylic styrene emulsion as a coupling agent

This investigation deals mainly with thermal stability and crosslinking density of EPDM/newsprint microfibers composites. The recycled newsprint microfibers were treated using a different ratio of acrylic styrene emulsion (5, 10, and 15 wt% fiber) as a bonding agent to reinforce EPDM rubber matrix. The effect of microfibers content, namely, 5 up to 50 phr (part per hundred part of rubber) and the effect of ionizing radiation on EPDM/newsprint microfibers composites properties were investigated. The microfibers structure and EPDM/microfibers composite were investigated using X‐ray diffraction and FTIR analysis; the results indicate that bonding has occurred between the treated newsprint microfibers and EPDM polymer matrix. EPDM/untreated newsprint microfibers composites have achieved higher crosslinking density than EPDM matrix up to 50 phr microfibers content and up to 100 kGy then decreased with increasing gamma irradiation dose. Meanwhile treatment of the microfibers using 10 wt% acrylic styrene leads to improve crosslinking density at any microfibers content. Thermogravimetric analysis (TGA) was carried out for the microfibers and their composites. TGA indicated that the thermal stability of microfiber was enhanced using acrylic styrene. Whereas there is a slight improvement in thermal stability and activation energy of the composites due to adding treated microfibers using 10 phr microfiber content treated using10 wt% acrylic styrene emulsion and irradiated with 60 kGy gamma radiation dose. J. VINYL ADDIT. TECHNOL., 25:E91–E106, 2019. © 2018 Society of Plastics Engineers     

Physical properties of irradiated thermoplastic elastomeric olefins based on (devulcanized rubber)/(high crystalline polypropylene) formulations

This work aims to produce thermoplastic elastomeric olefins based on devulcanized waste rubber (DR) and polypropylene (PP) compatibilized with poly(ethylene‐propylene‐diene monomer) (EPDM). The coupling of DR/PP in varying proportions with EPDM was investigated by Fourier‐transform infrared, X‐ray diffraction, and scanning electron microscopy techniques. A comparative study was established to evaluate the influence of EPDM content and radiation dose on the physical, mechanical, and thermal performance of DR/PP/EPDM composites. It was found that the synergism of EPDM incorporation and irradiation conditions up to 100 kGy remarkably decreased the PP T_m value, indicating a promotion in the PP and radiation sensitivity. J. VINYL ADDIT. TECHNOL., 21:33–41, 2015. © 2014 Society of Plastics Engineers     

Effects of gamma radiation on properties of halogen‐free flame retardant EPDM‐PVMQ rubber blends

In this study, the effects of gamma radiation on properties of ethylene–propylene–diene monomer (EPDM) and its blends with phenyl vinyl methyl silicon rubber (PVMQ) were studied. The samples were irradiated with the dose rate of 171.7 Gy/min, and the total dose was up to 500 kGy. Mechanical properties, electrical insulation, limiting oxygen index (LOI), crosslink density, and ATR‐FTIR spectroscopy of the rubber were carried out to characterize the properties via irradiation. The results indicated that PVMQ acted as an irradiation degradation retarder for EPDM. After a postvulcanized period corresponding to 50 kGy dose, the elongation at break and electrical insulation decreased with LOI unaffected, while the crosslink density and tensile strength presented a complicated change with the increasing of radiation dose. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Degradation of EPDM and FPM elastomers irradiated at very high dose rates in mixed gamma and neutron fields

Elastomers are widely used in radioactive environments, where ionizing radiations induce a deterioration of their properties due to degradative phenomena occurring in the polymer structure. Their radiation resistance is usually assessed using γ‐rays and relatively low dose rates, but in actual applications, they are often exposed to mixed radiation fields and higher dose rates. Ethylene propylene diene monomer (EPDM) is known for its excellent resistance to γ‐rays but absorbs a larger dose by neutron interactions than fluoroelastomer (FPM). In this work, EPDM and FPM were irradiated in mixed neutron and gamma fields, using high dose rates (from 22 to 700 kGy h^?1) and total absorbed doses between 0.2 and 3.5 MGy. The effects of irradiation were assessed by swelling tests, differential scanning calorimetry analysis and dynamic mechanical thermal analysis, and tensile tests. The results show that, even if irradiations were carried out in air, degradation took place under nonoxidative conditions owing to the high dose rates employed. Under such conditions, crosslinking is the dominant radiation‐induced reaction in both elastomers. Moreover, material degradation seems to be influenced mostly by the total absorbed dose and not by the type of radiation. Contrary to what observed at the lower dose rates employed with γ‐rays, major dose rate effects are not observed. POLYM. ENG. SCI., 59:2522–2532, 2019. © 2019 Society of Plastics Engineers     

Ageing studies of ethylene propylene diene monomer rubber/styrene butadiene rubber blends: Effects of heat,ozone, gamma radiation,and water

The ageing behavior due to the effects of heat, ozone, γ‐ radiation, and water on ethylene propylene diene monomer rubber/styrene butadiene rubber (EPDM/SBR) blends was studied. The tensile strength, crack initiation, ozone ageing, gamma radiation, and water resistance of the blends were measured and used to determine the extent of ageing. Tensile strength of blends of different compositions increased after thermal ageing for 96 h at 100°C probably due to the continued cross‐linking. It has been observed that an increase in EPDM in the blends improves the ozone resistance of the blends. Crack initiation was noted only in blends with lesser amount of EPDM and the cracks in such blends were found deeper, wider and continuous. With 15 kGy irradiation dose, the tensile strength of the blends found to be decreased while it increased with 80 kGy dosage of γ‐radiation. The elongation at break showed a decreasing trend with increased dosage of γ‐radiation. It has also been observed that the EPDM rich blends showed negligible water uptake. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

辐照对三元乙丙橡胶性能老化最新研究展望

随着国内各领域的发展需求,对作为辐射防护材料的三元乙丙橡胶提出了更高的要求,即具有较高的辐射屏蔽效果和优良的耐辐照性。简要综述了三元乙丙橡胶的辐照机理,并探讨了三元乙丙橡胶辐照前后性能变化,最后总结了提高三元乙丙橡胶耐辐照性能几种途径。     

Polychloroprene rubber/ethylene-propylene diene monomer/multiple walled carbon nanotube nanocomposites: synergistic effects of radiation crosslinking and MWNT addition

Synergistic effect of MWNT induced reinforcement and high energy radiation induced crosslinking on the physico-mechanical and thermal characteristics of polychloroprene rubber (PCR)/ethylene-propylene diene rubber (EPDM)/MWNT elastomeric nanocomposites was investigated. The extent of reinforcement, as assessed using the Kraus equation suggested high reinforcement of the blend on MWNT addition; though, the thermal stability and glass transition of the PCR and EPDM components were not significantly affected by MWNTs. The elastic modulus increased with the radiation dose as well as with the increase in MWNT content. The reinforcing mechanism of the nano-composites was studied by various micromechanics models all of which predicted higher moduli than the experimentally observed results, indicating agglomeration in the nano-composites. Nevertheless, in all the composites synergistic effect of radiation crosslinking and MWNT induced reinforcement were seen, suggesting radiation induced crosslinking between polymer and MWNT interface.     

耐辐照无卤低烟阻燃EPDM电缆绝缘材料的研制

研制耐辐照无卤低烟阻燃EPDM电缆绝缘材料.胶料优化配方为:EPDM(Nordel IP 4770P) 100,白炭黑 20,氧化锌 5,硬脂酸 1,氢氧化镁 120,硼酸锌 10,抗辐射剂(Polymer A) 25,石蜡油 20,防老剂MB 1,防老剂RD 2,助交联剂TAIC 1,助交联剂HVA-2 0.5,硫化剂DCP 3.优化配方胶料具有良好的阻燃性能、耐辐照性能和物理性能,可用于核电站1E级回路用电缆的绝缘.     

Gamma radiation aging of EVA/EPDM blends: Effect of vinyl acetate (VA) content and radiation dose on the alteration in mechanical,thermal, and morphological behavior

A series of ethylene vinyl acetate (EVA)/ethylene‐propylene diene elastomer (EPDM) blends (50/50 ratio) with four types of EVAs were prepared using brabender type batch mixer followed by compression molding. All compression‐molded samples were exposed to gamma radiation at 500, 1000, and 1500 kGy doses and were subjected to mechanical, compression set, thermal and morphological test. The % retention in tensile strength, elongation, and hardness were found higher for higher vinyl acetate (VA) containing radiation aged EVA/EPDM blends. The compression set value was decreased with increase of VA content. The thermal degradation kinetics of high VA containing irradiated blend (EVA40/EPDM) (EVA40 is 40%VA containing EVA) was found slower than those of lower VA containing blend (EVA18/EPDM). The surface morphology for EVA18/EPDM sample was transformed into more irregular one with more cracks and fragmented segments by aging at 1500 kGy dose while surface for EVA40/EPDM sample was found comparatively smooth, fine, and continuous with very few cracks and fragmented parts at similar dose. Thus, from the measured properties and morphology, it was revealed that the degree of degradation of blends kept on decreasing with increase in VA content. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46216.