影响HTV硅橡胶撕裂强度的因素

考察了白炭黑种类、羟基硅油用量、含氢硅油用量以及不同乙烯基含量生胶并用对热硫化(HTV)硅橡胶撕裂强度的影响。结果显示,气相法白炭黑的补强效果强于沉淀法白炭黑,且比表面积越大,硅橡胶的撕裂强度越高;随着羟基硅油加入量的增加,硅橡胶的撕裂强度先增后趋于稳定;含氢硅油的用量对HTV硅橡胶的撕裂强度基本没有影响;高乙烯基含量生胶和低乙烯基含量生胶并用能显著提高HTV硅橡胶的撕裂强度。较佳配方是:166 g 110-0生胶,4 g 112生胶、80 g QS-102气相法白炭黑、8.5 g羟基硅油、1.0 g含氢硅油、0.5 g乙烯基硅油,此时,HTV硅橡胶的撕裂强度达到21 KN/m。     

混炼型聚氨酯橡胶/聚十二内酰胺热塑性硫化胶动态硫化历程与性能

采用动态硫化方法制备了混炼型聚氨酯橡胶（MPU）/聚十二内酰胺（PA 12）热塑性硫化胶（TPV）,通过控制动态硫化时间探究了该TPV的动态硫化历程,同时研究了不同动态硫化阶段共混物的物理机械性能和动态力学性能。结果表明,随着动态硫化时间的延长,MPU/PA 12 TPV逐步完成相转变,在温度和剪切作用下,MPU相由连续相转变为分散相,而PA 12则由分散相转变为连续相;随着动态硫化时间的延长,MPU/PA 12共混物的储能模量升高,损耗模量降低,损耗因子减小。此外,随着动态硫化时间的延长,MPU/PA 12共混物的综合力学性能提高。     

有机硅密封剂高温力学性能研究

在温度25~250℃对3类硫化体系的5种有机硅密封剂的拉伸强度、180o剥离强度和剪切强度的研究表明:随着温度的升高,5种有机硅密封剂的拉伸强度、180o剥离强度和剪切强度均不断下降,其中拉伸强度和剪切强度降低的速率递减。有机硅密封剂的高温性能变化与硫化体系类型密切相关,脱氢硫化体系HM321密封剂在25~150℃拉伸强度、剪切强度和180o剥离强度均最高,但在25~250℃拉伸强度、剪切强度和180o剥离强度保持率均最低。脱氨硫化体系XY-602S有机硅胶粘剂在232~250℃的拉伸强度和剪切强度最高,25~250℃的拉伸强度保持率也最高。     

260万t/a两段加氢裂化装置催化剂硫化过程与分析

该蜡油加氢裂化装置引进美国UOP公司加氢裂化专利技术。催化剂采用UOP公司开发的KF-848加氢精制剂和HC-115LT加氢裂化催化剂,设计原料为科威特减压蜡油,经过加氢脱硫、加氢脱氮、以及加氢裂化等反应,生产优质的轻石脑油、重石脑油、航煤、柴油和加氢尾油。该装置于2014年6月建成,7月31日进行催化剂预硫化,硫化期间由于循环氢加热炉进料流量孔板仪表引出线焊缝多次出现裂纹泄漏,被迫中断三次,至8月20日12:00完成硫化。     

DYNAMICALLY VULCANIZED THERMOPLASTIC ELASTOMER BLENDS OF NATURAL RUBBER AND POLYPROPYLENE

Dynamic vulcanization of a soft grade of thermoplastic natural rubber (TPNR) was carried out using several concentrations of Hexamethylene N, N′ bis (tert-butyl peroxy carbamate) (HBTP). The blends were melt mixed in a Brabender plasticorder. The effectiveness of dynamic vulcanization was investigated using the Brabender plastograms, swelling index measurements, rheological behavior by means of a capillary rheometer, dynamic mechanical properties, and tensile testing. It was found that varying the HBTP concentration had a great influence on the rheological behavior as well as the dynamic and tensile properties of the material. The increase of HBTP dosage resulted in an increase of the extent of crosslinking and caused an increase of the elastic modulus and a reduction of the loss modulus. The ultimate tensile strength and elongation at break also increased with increasing HBTP loading. The rheograms indicated that the blends exhibit a pseudoplastic behavior.     

Dynamically Vulcanized EPDM/PP (40/60) Blends

Dynamically vulcanized thermoplastic elastomer (TPE) blends were first described by Fisher. In the 1960s, the usage of TPE was low. However, the consumption of TPE is increasing today. Due to hard and soft polymer phases in its structure, TPE replaced a lot of materials. TPE materials are preferred today due to their good thermal properties, oxidation resistance, transparency, adhesion, compatibility with other polymers etc. As a result of the studies that were done in 1975, TPV—vulcanized thermoplastic elastomers were developed. In this study, TPV elastomers were produced by forming crosslinks with peroxide from different ratios, of EPDM and PP. Mixing was done with twin screw extruder. After that yield and tensile strength, the modulus of elasticity, % elongation, Izod impact strength, hardness, Melt Flow Index (MFI), Vicat Softening Point, Heat Deflection Temperature (HDT), and density of crosslinks were determined. Thermal transition temperatures and microstructure were determined with DSC and SEM, respectively.     

挤出用溴化丁基橡胶硫化体系的研究

溴化丁基橡胶几种典型硫化体系的对比实验,结果表明,用氧化锌体系硫化的溴化丁基橡胶具有良好的焦烧安全性,比较适宜于挤出用;加入促进剂HVA-2,可显著提高胶料的硫化速度和交联程度,并改善焦烧安全性;当氧化锌用量为4份,HVA-2用量为1.5份时,胶料具有较佳的综合物理性能和加工安全性。     

聚烯烃类热塑性弹性体研究进展

介绍了聚烯烃热塑性弹性体(TPO)的生产工艺、结构、性能及应用,叙述了乙烯-辛烯共聚物(POE)、热塑性动态硫化胶(TPV)和乙烯-辛烯(OBC)3种TPO的特点及应用领域.建议应对小型装置进行改造,提高产量,加大投入力度研发设计低耗能、低污染和高产量的大型装置;消化、吸收国外技术的同时加快创新力度;重点研发汽车、建筑...     

微生物凝固天然橡胶交联密度的研究

采用核磁共振交联密度仪,考察了微生物凝固天然橡胶（NR-m）和酸凝固天然橡胶（NR-a）在硫化过程交联密度（XLD）、网链含量（AMc）、自由小分子含量（AT2）以及相邻交联点间的分子质量（Mc）的动态变化规律。研究结果表明,NR-m硫化胶的XLD比NR-a的高,NR-m硫化胶磁化曲线随时间衰减的速率比NR-a快,纵向松弛时间（T1）和横向驰豫时间（T2）比NR-a低,NR-m硫化胶网链部分的质量含量（AMc）明显高于NR-a的,而自由末端数则明显比NR-a的低。这表明微生物凝固法促进了天然橡胶的硫化作用,提高了硫化胶的交联密度。     

聚酰胺类TPV的研究进展

以聚酰胺为基体采用动态硫化工艺制备的热塑性动态硫化弹性体（TPV）是一类颇具发展潜力的热塑性弹性体（TPE）。目前很多高性能橡胶材料都可以采用聚酰胺类的TPV代替,特别是我国汽车工业的高速发展,为这种TPV的发展提供了巨大的空间。本文重点介绍了这类TPV的研究进展。