环氧化反式-1,4-聚异戊二烯的硫化及硫化胶性能

研究了4种不同环氧基摩尔分数化反式－1，4－聚异戊二烯（ETPI）的硫化及硫化胶性能，并对其在轮胎胶料中的应用进行了探讨，结果表明，ETPI可用传统的硫黄－促进剂体系进行硫化，在3类常用促进剂（M，CZ，TMTD）中，以CZ为硫化促进剂时的硫化曲线最为理想，随着环氧基摩尔分数的增加，ETPI硫化胶的弹性变差，耐磨性，耐油性，与轮胎帘线的粘接性和抗湿滑性较未硫化反式－1，4－聚异戊二烯（TPI）均有大幅度提高，但生热和滚动损失有所增加。在100℃下热空气老化结果表明，ETPI硫化胶属于交联反应为主的老化历程。环氧基摩尔分数为17％－25％的ETPI综合性能最好，ETPI与丁苯橡胶并用于胎面胶中可显著地提高其抗湿滑性能和耐油性，并用于天然橡胶帘布层胶中能显著地提高其与钢丝或尼龙帘线的粘接性。     

用过氧甲酸水相悬浮法制备环氧化反式-1,4-聚异戊二烯

研究了用过氧甲酸体系水相悬浮法制备环氧化反式-1,4-聚异戊二烯(ETPI)的合成条件,并用红外光谱和核磁共振氢谱对ETPI及其环氧基团含量进行了表征和计算。结果表明,用过氧化氢与甲酸合成ETPI较适宜的条件为反应温度40℃、甲酸/过氧化氢/反式-1,4-聚异戊二烯(摩尔比)0.50/1.00/0.50及反应时间1～2h。在此条件下可以制备环氧度10%左右的疏松粉末状ETPI。     

环氧化反式-1,4-聚异戊二烯的毛细管流变行为

采用毛细管流变仪研究了不同环氧度的环氧化反式-1,4-聚异戊二烯(ETPI)的流变行为。结果表明,ETPI的非牛顿指数小于1.00,熔体为假塑性流体;随着ETPI环氧度的增大,非牛顿指数略有降低。环氧度为30%的ETPI在剪切速率较低时,其熔体的黏流活化能较大,说明对温度的敏感性较大;随着剪切速率的增大,黏流活化能降低,ETPI对温度的敏感性降低。随着剪切速率的增大,ETPI熔体在入口区的弹性形变增大;在相同剪切速率下,ETPI的环氧度越大,入口区的弹性形变越大。     

环氧化反式1，4-聚异戊二烯塑炼行为的研究

采用转矩流变仪研究环氧化反式1,4-聚异戊二烯(ETPI)的塑炼行为及其在塑炼过程中的老化降解行为。结果表明:随着环氧度的提高,ETPI达到塑化点的时间缩短,较高环氧度的ETPI的塑炼行为对温度更为敏感。ET-PI在塑炼过程中发生明显的副反应,生成醇及呋喃环结构,且环氧度越高,副反应越严重。ETPI在塑炼前期,首先发生交联反应,进而发生交联键的断裂引起凝胶质量分数减小。     

预处理法合成环氧化反式-1,4-聚异戊二烯及其结构与性能

采用预处理法对反式-1,4-聚异戊二烯(TPI)进行环氧化改性,合成了具有不同环氧度的环氧化TPI( ETPI),考察了预处理剂/水(体积比,下同)、投料比[过氧乙酸/TPI(摩尔比,下同)]对ETPI环氧度的影响,并对ETPI的结构及性能进行了表征.结果表明,预处理法合成的ETPI其环氧度显著提高,当预处理剂/水为7...     

水相悬浮法氯化反式-1,4-聚异戊二烯的性能

采用水相悬浮法，对一定相对分子质量的反式-1，4-聚异戊二烯颗粒进行氮化，制得的氮化反式-1，4-聚异戊二烯（CTPI），通过DSC与偏光显微镜看出，随着氮含量的升高，TPI的结晶度下降，熔点降低，温度升高会导致脱HCl现象出现；随着氮含量的升高，CTPI极性升高，在极性溶剂中的溶解性增加；特性粘数下降。     

环氧化反式- 1,4-聚异戊二烯的合成

以负载钛催化异戊二烯本体沉淀聚合所合成的粉状反式-1,4-聚异戊二烯(TPI)为原料,过氧乙酸水溶液为介质,研究了水相悬浮法合成环氧化TPI(ETPI)的合成条件及动力学特性,并考察了ETPI的环氧度测定方法和反应残液的回收利用问题.结果表明,用该法合成ETPI适宜的反应条件为体系pH值等于4.5,且于约20℃反应1～3 h,可获得环氧度小于50%的ETPI;聚合动力学特性为过氧乙酸参与了环氧化反应,过氧乙酸的生成反应可忽略不计,反应的活化能为(72±5)KJ/mol,ETPI的环氧度可由反应前后过氧乙酸浓度的变化求得,与核磁共振法测得的环氧度相比,误差为±10%,有利于环氧度的控制.     

反式-1， 4-聚异戊二烯橡胶的制备及其在轮胎胶料中的应用（一）

介绍反式-1，4-聚异戊二烯橡胶（TPI）的结构与性能、负载钛系催化本体沉淀聚合法制备TPI的工艺、TPI在半钢子午线轮胎和全钢子午线轮胎中的应用，以及环氧化TPI（ETPI）和反式丁二烯-异戊二烯（TBIR）-TPI复合胶等TPI改性材料的性能。TPI的负载钛系催化本体沉淀聚合工艺的生产成本较低，且在生产过程中无三废排放；用TPI制备的轮胎耐屈挠性能、耐磨性能较好，每100 km油耗降低约2.5％，行驶里程延长约20％。     

气-固相法氯化反式-1,4-聚异戊二烯

采用气-固相法对反式-1,4-聚异戊二烯(TPI)进行氯化改性,制得氯化反式-1,4-聚异戊二烯(CTPI)。主要探讨了氯含量对反式-1,4-聚异戊二烯结晶度的影响,以及氯化后TPI结构的变化。分析结果表明,随着氯含量的升高,CTPI的结晶度下降,熔点降低。随TPI粒径尺寸减小以及其相对分子质量分布变窄,氯化则越容易,氯化程度越均匀,结晶度降低越多。结构表征发现,CTPI分子链结构包括碳-碳双键氯加成、侧甲基氯取代、环氧基团等。     

环氧化反式-1,4-聚异戊二烯的合成与表征

用50L搪瓷釜,过氧乙酸水相悬浮法合成环氧化反式-1,4-聚异戊二烯(ETPI),通过改变过氧乙酸/TPI双键的摩尔比制备了不同环氧度的ETPI,并分别采用红外光谱(IR)、核磁共振(1 HNMR)等手段对TPI的环氧化程度及副反应进行了表征。红外测试结果表明,ETPI环氧度可以达到34.6%,核磁测试结果显示在2.71×10-6处出现明显环氧基团特征峰,定量计算得到典型环氧度为8.7%。     

ETPI用量和环氧度对NR/ETPI并用胶性能的影响

研究NR/环氧化反式1,4-聚异戊二烯（ETPI）并用比和ETPI环氧度对NR/ETPI并用胶性能的影响。结果表明,加入适量的ETPI,可以明显地提高NR胶料与钢丝的粘合性能。当NR/ETPI并用比为85/15时,NR/ETPI并用胶的耐磨性能和抗湿滑性能较好,抽出力的增幅较大;当ETPI的环氧度为15%时,NR/ETPI并用胶的性能最优异。     

ETPI改性PVC性能的研究

研究了反式-1,4-聚异戊二烯(TPI)及环氧化反式-1,4-聚异戊二烯(ETPI)对聚氯乙烯(PVC)性能的影响,并与丁腈橡胶、粉末丁腈橡胶、氯化聚乙烯改性PVC做了比较。结果表明:不同环氧度的ETPI均对PVC有明显的增韧作用;与丁腈橡胶、粉末丁腈橡胶、氯化聚乙烯相比,环氧基摩尔分数为25%的ETPI对PVC的增韧效果最显著。     

环氧化反式1，4-聚异戊二烯在轮胎中的应用

研究环氧化反式1，4-聚异戊二烯(ETPI)在轮胎锦纶帘布层胶和钢丝带束层胶中的应用。结果表明，在锦纶帘布层胶中使用15份ETPI-15等量替代NR，在钢丝带束层胶中使用5份ETPI-25等量替代NR，硫化胶的综合性能良好，特别是与帘线的粘合性能优异。     

Observation of phase separation of epoxidized trans-1,4-polyisoprene and mechanism exploration through 13C-NMR

Selectively epoxidized trans-1,4-polyisoprene (SETPI) and randomly epoxidized trans-1,4-polyisoprene (RETPI) were fabricated successfully through modified surface water-phase suspension epoxidation and solution random epoxidation, respectively. The effects of fabricated method and epoxy degree of ETPI on the glass transition temperature (T _g), dynamic mechanical properties and phase separation phenomenon of the as-fabricated polymer have been investigated by different scanning calorimetry, dynamic mechanical analyzer and phase contrast microscope. The double bonds and epoxy groups sequence structure distribution of different ETPI have been observed and analyzed by ¹³C-NMR. There is a great deal of difference in the microstructure and sequence distribution of epoxy group in ETPI with different synthesis methods and epoxy degree. The results show that distribution of epoxy group in SETPI is nonuniform which brings about the phase separation.     

Vulcanizates of epoxidized trans-polyisoprene: morphology,mechanical and dynamic properties

Morphology, curing characteristics, mechanical and dynamic properties of vulcanization of epoxidized trans-polyisoprene (ETPI) with different epoxy content were investigated. From scanning electron microscopy micrographs, it is observed that ETPI vulcanizates were a two-phase system. DSC shows that the residual crystallization reduced with increasing epoxy content. With increasing epoxy content, the induction period of cure shortened gradually as well as tensile strength, elongation at break, hardness and tear strength decreased. It is important to note that the wear resistance increased gradually with the increasing of epoxy content. Rebound values at 23 and 70 °C decreased which indicate that damping capacity and wet resistance performance increased, but the rolling resistance increased. DMA tests further show that wet resistance performance enhanced, damping capacity improved, but rolling resistance increased with increasing epoxy content of ETPI.     

Epoxidation of high trans‐1,4‐polyisoprene and its properties

A new organic‐solvent‐free water‐phase suspension method was used to synthesize partially epoxidized high trans‐1,4‐polyisoprene (TPI) to improve its properties, including oil resistance and wet‐skid resistance. The epoxidation was conducted in an aqueous peracetic acid solution and on the TPI granules prepared by a bulk precipitation method with supported titanium catalyst. The effects of the synthesis conditions, including reaction temperature, reaction time, and pH value, on the epoxy content were investigated. Epoxidized trans‐1,4‐polyisoprene (ETPI) with epoxy contents between 10 and 80% were obtained within 4 h. Both the amorphous and crystalline regions of TPI were epoxidized. The crystallization properties decreased with increasing epoxy content. ETPIs possessed lower mechanical properties than TPI but could be enhanced by vulcanization. The oil resistance and wet‐skid resistance were significantly improved after epoxidation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008