SEBS热塑性弹性体的制备研究

SYNTHESIS OF SEBS THERMOPLASTIC ELASTOMER

采用环烷酸镍和三异丁基铝催化剂对SBS进行加氢,制备了SEBS热塑性弹性体。研究了催化剂配比及其用量、SBS溶液浓度,加氢温度、氢气压力等对SEBS加氢度的影响,获得了当SBS溶液浓度为10％(质量)、环烷酸镍用量为1.3mg/gSBS时,反应1h加氢度可达87.7％的良好效果。通过对SEBS进行结构表征和性能测试,表明SEBS是一种耐老化性能良好的热塑性弹性体。

The hydrogenated product of styrene- butadiene -styrene triblock copolymer (SEBS ) was prepared by using nickel naphthenate (Ni)and triisobutyl aluminum (Al) as catalysts in solution at different temperatures and hydrogenation pressures . The experimental results indicated that the hydrogenation of SBS was accomplished at moderate conditions (hydrogen pressure 0.15 - 0.35 MPa and temperature 30-80°C ). The rate of hydrogenation for this system increased with the increaseof hydrogen pressure and temperature , and with the increase of nickel contents in the conditions of l.3- 30 mg nickel per gram SBS at Al/Ni molar ratio of 3 :1 . Table 1 shows the hydrogenation dependence of catalyst composition (Al/Ni ratio) for these systems .It is dear that the hydrogenation content was as high as 96% for the ratio of Al/Ni from 2 to 3 whereas it was around zero at low (1.5) or high (6.0) ratio of Al/Ni .The effect of SBS concentration on the hydrogenation of SBS is listed in Table 2 . The rate of hydrogenation increased with the decrease of SBS concencration at the begining of hydrogenation process . but the hydrogenation contents were similar (around 90%) after 1 h regardless of SBS concentration .The structures and properties of these SEBS were also characterized and measured . It was showed that the glass transition temperatures for the rubber blocks of SBS and SEBS were -47.1°C and -54.3°C, and for the plasticExperiment conditions: 80°C, hydrogen pressure 0.196 -0.294 MPa, 2.5mg Ni/ g SBS , in 1 h , 2.5% (mass)solids in cyclohexane .Experiment conditions : 80°C, hydrogen pressure 0.196 - 0.294MPa ,1.25mg Ni/g SBS ,Al/Ni = 3.0.blocks of SBS and SEBS were 108.6°C and 115.7°C respectively . The mechanical properties of SEBS was somewhat superior to those of SBS ,but the aging stability of SEBS was obviously superior to that of SBS .