辐射预硫化技术在EPDM发泡材料制备过程中的应用研究

以三元乙丙橡胶（EPDM）为基材,采用电子加速器辐照技术对其进行辐射预硫化处理,研究了敏化剂TMPTMA对硫化参数的影响及其敏化效果,并研究了不同吸收剂量下,发泡制品的外观、材料力学性能、吸水率和压缩永久变形的变化情况。结果表明：TMPTMA对三元乙丙橡胶有较好的敏化效果;在辐射吸收5～15kGy剂量范围内,发泡材料的闭孔性变好,力学性能也随之提高。     

二元饱和橡胶的辐射硫化

报道了多官能团单体对二元乙丙橡胶及二元乙丁橡胶辐射硫化的影响。研究表明,二甲基丙烯酸三乙二酯对乙丙橡胶的辐射硫化具有良好的促进作用,二甲基丙烯酸三乙二酯不仅能降低乙丙橡胶的辐射硫化剂量,而且能提高硫化橡胶的强度。多官能团单体对乙丁橡胶辐射硫化的促进作用则不明显。     

辐射技术在橡胶硫化中的应用

介绍了橡胶辐射硫化研究的发展,橡胶辐射硫化的特点及其应用领域,国内橡胶辐射硫化的状况和国外橡胶辐射硫化工业化的规模。     

橡胶辐射硫化

橡胶辐射硫化是在高能射线(钴源产生的γ射线或电子加速器产生的高能电子束)辐照下产生交联的过程。由于不需要添加硫化剂及在常温、常压下硫化,因此,具有产品纯度高、工艺简单及节省能源的明显优点。     

丹参制剂改善辐射硫化胶膜抗老化性能的研究

采用热老化方法研究了丹参制剂对RVNRL胶膜抗老化性能的影响.结果表明:丹参制剂有较好的抗老化性能;在3种流分的丹参制剂中,酒沉前丹参制剂的抗老化性能最佳;对于SM-a(c-1999)制剂来讲,丹参生药含量为7.50%是适宜的;不同产地的丹参制剂的抗老化性能也会有所不同.     

天然橡胶乳液辐射硫化研究及应用

叙述了天然橡胶乳液辐射硫化的优点、发展历史、机理、影响产品性能的主要因素和辐射硫化工艺。辐射硫化有利于医疗卫生和环保事业。为了实现工业化生产，必须降低生产成本。采用加速器进行辐射硫化，其成本与传统的化学硫化相当，预示有较好的市场前景。     

氯丁橡胶辐射硫化工艺的研究

研究了氯丁橡胶的辐射硫化工艺,发现含有４份多官能团单体４Ｇ,４份氧化镁及３０份碳黑的氯丁橡胶试样接受３０￣５０ｋＧｙ电子束辐射后,发生了交联。产品物理性能均达到或超过了化学硫化可达到的数值,因而在某些场合氯丁橡胶辐射硫化法可以取代化学硫化法。     

添加剂对高温硫化硅橡胶耐辐射性能的影响

研究了五种不同的芳香族添加剂（联苯、萘、菲、二苯甲酮、二苯乙炔）对高温硫化硅橡胶的耐辐射性能的影响。分析了在真空下经受400kGy和600kGy的γ射线辐照下,两交联点间有效链平均分子量Mc和力学性能的变化。讨论了芳香族添加剂的辐射保护机理。结果表明芳香族添加剂,尤其是二苯乙炔,能提高硅橡胶的耐辐射性能。     

Radiation processed polychloroprene-co-ethylene-propene diene terpolymer blends: Effect of radiation vulcanization on solvent transport kinetics

Blends of polychloroprene rubber (PCR) and ethylene propylene diene terpolymer rubber (EPDM) of different compositions were made and exposed to different gamma radiation doses. The radiation sensitivity and radiation vulcanization efficiency of blends was estimated by gel-content analysis, Charlesby-Pinner parameter determination and crosslinking density measurements. Gamma radiation induced crosslinking was most efficient for EPDM (p₀/q₀ ∼ 0.08), whereas it was the lowest for blends containing 40% PCR (p₀/q₀ ∼ 0.34). The vulcanized blends were characterized for solvent diffusion characteristics by following the swelling dynamics. Blends with higher PCR content showed anomalous swelling. The sorption and permeability of the solvent were not strictly in accordance with each other and the extent of variation in two parameters was found to be a function of blend composition. The ΔG values for solvent diffusion were in the range −2.97 to −9.58 kJ/mol and indicated thermodynamically favorable sorption for all blends. These results were corroborated by dynamic swelling, experimental as well as simulated profiles and have been explained on the basis of correlation between crosslinking density, diffusion kinetics, thermodynamic parameters and polymer-polymer interaction parameter.     

Study on radiation vulcanization of natural rubber latex

The effect of dose rate of 60Co γ-ray on radiation vulacnization of natural rubber latex is studied using Malysian latex with 0.002 mass fraction KOH and 0.05 mass fraction n-BA.Results show that,when radiation doses are 20 and 15kGy,only that the dose rates are greater than 0.49 and 1.6 kGY/h,respectively can make the tensile strength of latex film meet the related standard;besides,storage time of radiation vulcanization latex has no effect on physical properties of the film.     

低能电子束循环辐射硫化天然橡胶乳液

应用250keV低能电子束循环辐射硫化二丙烯酸壬酯（1,9-nonanedilo diacrylate，NDDA）敏化的天然橡胶乳液，探讨了影响低能电子束循环辐射硫化天然橡胶乳液的因素。结果表明，提高电子束束流，可缩短辐射硫化时间；40％的天然橡胶乳液更适合低能电子束的辐射硫化；适当提高循环乳液的重量有利于辐射硫化乳液的质量控制。     

Effect of gamma irradiation on ethylene propylene diene terpolymer rubber composites

Composites of ethylene propylene dine terpolymer rubber (EPDM), high density polyethylene (HDPE) and ground tire rubber powder (GTR) at different ratios were subjected to gamma irradiation at various doses up to 250 kGy. The physical, mechanical and thermal properties were investigated as a function of irradiation dose and blend composition. Gamma irradiation led to a significant improvement in the properties for all blend compositions. The results indicate that the improvement in properties is inversely proportional to the substituted ratio of GTR, attributed to the development of an interfacial adhesion between GTR and blend components. The results were confirmed by examining the fracture surfaces by scanning electron microscopy.     

辐射硫化丁腈橡胶拉伸强度的模糊减法聚类模型应用研究

利用模糊减法聚类构建了丁腈橡胶乳液辐射硫化后的拉伸强度预测模型,并将辨识模型与实验数据进行对比,通过检验数据来检验模糊模型的可靠性。模型预测值与实验值相关性为0.8222,由此可知模糊辨识方法建模精度高,计算量小,用此模型来分析丁腈橡胶乳液辐射硫化后拉伸强度的变化规律非常直观方便。这为材料应用模糊建模方法分析开辟了新思路。     

Effect of insulator environment on thermal ageing estimations for ethylene propylene rubber insulated nuclear power plant cables

Thermal ageing estimations merely focus on the degradation of cable insulator materials without considering their arrangement within the cable structure, by surrounding jacket or colorant pigments. This study reconsidered thermal ageing estimations based on the insulator elongation at break (EAB) degradation progress for flame retardant ethylene propylene rubber (FR-EPR) insulators within the whole cable structure. FR-EPR insulators were aged using two methods. In the first method, the insulators were heated, including jacket material at 125?°C, 150?°C, and 160?°C for 2208, 336, and 264 h, respectively. In the second method, the insulators were heated without jacket at 125?°C for 3480 h, and at 160?°C for 264 h. It was expected that the EAB degradation progress would be more severe when the FR-EPR insulators were aged without jacket. However, the results contradicted previous expectations, and the special heat-resistant polyvinyl chloride jacket accelerated the EAB degradation. In addition, the black FR-EPR insulators showed values that deviated from the predictions for the activation energy (E_a) and equivalent times compared to the white and red insulators due to the use of carbon black as a pigment. The reduced equivalent times for thermally aged FR-EPR insulators with jacket in this study were evident compared with the current degradation database for FR-EPR insulators degraded without jacket.     

Studies on mechanical, thermal and morphological properties of irradiated recycled polyamide and waste rubber powder blends

The aim of this article was to show the effect of gamma irradiation on mechanical and thermal properties of recycled polyamide (rPA) copolymer blended with different content of waste rubber powder (WRP). In order to study the structural modifications of prepared blends have been subjected to irradiation doses up to 200 kGy were applied to all samples. Non-irradiated blends were used as control samples. Mechanical properties, namely, tensile strength (TS), elastic modulus, elongation at break and hardness have been followed up as a function of irradiation dose and degree of loading with rubber content. Furthermore, the influence of radiation dose in the thermal parameters, melting temperature, heat of fusion, ΔH_f of the recycled PA and its blend with waste rubber powder (WRP) was also investigated.     

硫酸镁对人脐静脉血管内皮细胞辐射防护的作用

将对数生长期的人脐静脉血管内皮细胞(Human umbilical vein endothelial cell,HUVEC)分为对照组、照射组和实验组,照射组和实验组均接受γ-射线辐照,实验组于照射前0.5 h加入硫酸镁。采用CCK-8法检测细胞存活率,流式细胞仪检测细胞周期分布和凋亡率,硫代巴比妥酸法检测丙二醛(MDA)水平。结果显示,6.25mg·mL-1以下浓度的硫酸镁对HUVEC细胞存活率无明显影响;6.25 mg·mL-1的硫酸镁可提高照射后HUVEC细胞的存活率,改善γ-射线诱导的HUVEC细胞G2/M期阻滞,降低HUVEC细胞凋亡率。提示硫酸镁对HUVEC细胞辐射损伤具有一定的防护作用。     

Effect of carbon black on the properties of irradiated recycled polyamide/rubber waste composites

In the present study, the synergistic effect of carbon black (CB) content % and gamma irradiation on some mechanical, thermal, chemical stability and micro-structural properties of the moulded waste polyamide copolymer/recycled waste rubber powder (rPA/WRP) 50/50 was investigated. The ternary composites of CB concentrations, 6, 12, 18, and 24 wt.%, were irradiated with doses of 50, 100, 150 and 200 kGy. The composites mechanical properties: tensile strength, elongation at break, and hardness, and the thermal properties: melting temperature (T_m) and (ΔH) were measured. Also, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), swelling and chemical stability were investigated.