Variation of free volume parameters of polyalkylmethacrylate derivatives in the range from 15 to 300 K probed by positron annihilation lifetime measurement
Variation of free volume parameters of polyalkylmethacrylate derivatives in the range from 15 to 300 K probed by positron annihilation lifetime measurement
复制标题
通过正电子湮没寿命测量探测聚甲基丙烯酸烷基酯衍生物自由体积参数在15~300 K范围内的变化
DOI：
10.1007/bf02056394
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
K. Horie
中科院分区：
文献类型：
--
作者：
H. L. Li;Y. Ujihira;S. Tanaka;T. Yamashita;K. Horie
PMMA、PEMA、PiPMA、PnPMA 和 PnBMA 的正电子湮灭寿命测量在 15 至 300 K 的温度范围内进行，其中这些聚甲基丙烯酸烷基酯发生 δ、γ 和 β 弛豫跃迁。根据最长寿命组分计算出的自由体积尺寸和含量随温度的变化与通过聚合物的介电、粘弹性和动态机械松弛数据获得的结果相关。聚甲基丙烯酸烷基酯的自由体积尺寸和含量、表观自由体积分数和尺寸分布的变化与侧链的旋转转变密切相关。自由体积的位置，其中正电子湮灭物可以估计在与侧酯链的氧原子结合的烷基附近。
Positron annihilation lifetime measurements of PMMA, PEMA, PiPMA, PnPMA and PnBMA were performed in the temperature range between 15 and 300 K, where δ, γ and β relaxational transitions occur for these polyalkylmethacrylates. The variations of free volume size and content calculated from the longest lifetime component against temperature are correlated to the results obtained by dielectric, viscoelastic and dynamic mechanical relaxation data of the polymers. The variations of free volume sizes and contents, apparent free volume fraction and size distribution of the polyalkylmethacrylates are well correlated with the rotational transitions of side chains. The location of free volumes, in which positronium annihilates can be estimated near the vicinity of alkyl groups bound to oxygen atom of side ester chains.