【摘要】 本工作以电镜研究了分子量不同的稀土催化聚合的聚丁二烯(Ln-PB)在不同温度下的结晶形态及球晶生长速率。表明在-10℃——80℃的温度范围内,Ln-PB可呈现六种不同的结晶形态,并根据结晶成核理论进行了讨论。从球晶的大小及形态可以看出Ln-PB在-20℃以上不能均相成核,且球晶的生长主要是单二维核生长。在-20℃——65℃,均相成核速率随温度的下降变快。而球晶的生长也是以多二维核生长为主。本工作还从晶片的厚度计算了Ln-PB的结晶的比表面能(σ_e),说明当〈M〉_η<10~6时,σ_e随分子量的变化很小;而当〈M〉_η>10~6时,σ_e随分子量的增加而明显增大。更多还原

【Abstract】 This paper presents our study of the effects of molecular weight andtemperature on the crystallization morphology of cis-l, 4-polybutadiene poly-merized with rare-earth catalyst (Ln-PB) by electron microscopy. It can be seen that for Ln-PB, in the range of -10°——80℃, the re aresix kinds of spherulite morphology, and at the same temperature withdecrease of molecular weight, the density and the degree of perfection of thecrystal is increased. According to the size and morphology, one can recognize: above -20℃,crystal growth only occurs on heterogeneous nuclei and below -20℃, homo-geneous nucleation becomes possible. The surface free energy, σe, has been determined. The results showthat: σ_e is about 20 erg/cm~2 when 〈M〉_η<10~6, but increases with increaseof molecular weight when 〈M〉_η>10~6.更多还原