The effect of molecular weight on the rheological and tensile properties of poly(epsilon-caprolactone)
The effect of molecular weight on the rheological and tensile properties of poly(epsilon-caprolactone)
复制标题
DOI：
10.1016/0378-5173(95)04404-3
复制
发表时间：
1996-06-17
影响因子：
5.8
通讯作者：
Staniforth, JN
中科院分区：
文献类型：
--
作者：
Grosvenor, MP;Staniforth, JN
通过催化降解得到了聚（epsilon-己内酯）（PCL）的分子量分数，并用流变学方法对其进行了表征。假塑性行为是发现较高的分子量分数，其程度减轻，聚合物链的热运动增加。粘度/分子量关系的指数因子表明，馏分高于粘性流动的临界分子量，确定为15-16 000。黏性流动的活化能与分子质量呈反比关系，并讨论了其意义。熔体淬火导致较低的熔体粘度，这是由于形成额外的非晶态区域降低了熔点。拉伸测试表明PCL是一种脆性材料，其分子量为bbb16900，是形成自由薄膜所必需的。伸长率和抗拉强度随分子量的增加而增加，但仍然保持在较低的水平，这表明所研究的PCL分子量范围较低，结晶度较高。结果表明，PCL具有良好的流变学和拉伸性能，经改性后将成为制药粉末涂层新技术的潜在候选材料。
Molecular weight fractions of poly(epsilon-caprolactone) (PCL) were obtained by catalytic degradation and characterised by rheological measurements. Pseudoplastic behaviour was found the higher molecular weight fractions, the degree of which lessened as the thermal motion of the polymer chains increased. The exponential factor of the viscosity/molecular weight relationship indicated that the fractions were above the critical molecular weight for viscous flow determined as 15-16 000. Activation energies for viscous flow showed an inverse relationship with molecular weight, the significance of which has been discussed. Melt quenching resulted in lower melt viscosities due to a reduction in melting point by formation of additional amorphous regions. Tensile measurements indicated that PCL was a brittle material with a molecular weight of > 16 900 being required for free film formation. Elongation and tensile strength values increased with molecular weight although remaining low, indicating both the low molecular weight range investigated and the high degree of PCL crystallinity. PCL showed that it had rheological and tensile properties that with modification would make it a potential candidate in the novel technique of powder coating of pharmaceutical compacts.