中文摘要：

研究了不同温度下苯乙烯-丁二烯-苯乙烯嵌段共聚物（SBS）的粘弹弛豫与相形态．DSC分析发现，SBS的相结构特别是其中质量分数较低的PS相畴的大小受热历史影响显著．用TEM表征了SBS的双相连续形态和两相相畴尺寸．用动态流变学方法研究了不同温度下SBS嵌段大分子的松弛行为．结果表明，在低于PS相玻璃化转变温度时，嵌段分子中的PB段已可发生运动；而当高于PS玻璃化转变温度后，由于PB与PS间的相互作用及PB的链缠结所限制，体系仍保持较高的弹性模量，呈现“第二平台”特征流变行为．

英文摘要：

Phase behavior and viscoelastic relaxation of styrene-butadiene-styrene triblock copolymer （SBS） were investigated. Through the TEM observation, it can be found that there exist cocontinuous phases in the SBS and the dimension of each phase can be confirmed. The DSC test reveals that the heating history that samples exposed to have a significant effect on SBS phase structure, especially for PS phase with a small mass proportion in SBS. There is an order-disorder transition with temperature increasing, and the transition temperature is considered to be related to the size of PS domain. The dynamic rheological measurements were conducted to evaluate the viscoelastic relaxation behavior of SBS triblock copolymer at different temperatures. Three relaxation peaks appearing on the temperature dispersion curve of dynamic loss tangent at different frequencies is attributed to the relaxation of various motorial unit of SBS. Differing from PS homopolymer, with the increase of temperature, SBS still presents a high elastic modulus because of the interaction between PS and PB phases, and the entanglement of PB chains. Furthermore, an obvious peak as shown in the dynamic frequency sweep curves is involved in the order-disorder transition when the temperature is beyond 98℃.