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实验订定了1,2-链节含量分别为8％,30％和90％的1,2-聚丁二烯在30℃甲苯溶液中的Mark-Houwink方程[η]=KM~(?)。发现不同样品的α值基本相同,而K值确实随1,2-链节含量的增加而减小,说明溶液中分子链线团变得紧密了。用线膨胀法和Stockmayer-Fixman方程及分子链的统计力学方法,分别得到了样品的玻璃化温度T_g,和它们的分子链内旋转空间位阻因子σ。它们二者符合T_g=A(σ—b),其中A=174(K),b=0.68。反映了1,2-链节对分子链内旋转的阻碍作用。进一步的研究表明,低1,2-链节含量对应着较低的分子链内旋转势垒和内旋转异构化能。
The Mark-Houwink equation [η] = KM ~ (?) Of 1,2-polybutadiene with 1,2-mercaptoethane content of 8%, 30% and 90% . It is found that the α values of different samples are basically the same, while the value of K does decrease with the increase of 1,2-chain content, which indicates that the molecular chain clumps in the solution become compact. The glass transition temperature T_g of the sample and the rotational steric hindrance factor σ in the molecular chain were obtained respectively by using the method of linear expansion and the method of Stockmayer-Fixman and the statistical mechanics of the molecular chain. They both satisfy T_g = A (σ-b), where A = 174 (K) and b = 0.68. The 1,2-link showed the impediment to the rotation within the molecular chain. Further studies have shown that the content of low 1,2-linkages corresponds to a lower intramolecular rotational barrier and internal rotational isomerization energy.