Free volumes and their distribution in crosslinked polysiloxanes probed by positron annihilation lifetime technique

被引：31

作者：

Li, HL

Ujihira, Y

Yoshino, T

Yoshii, K

Yamashita, T

Horie, K

机构：

[1] Univ Tokyo, Adv Sci & Technol Res Ctr, Meguro Ku, Tokyo 153, Japan

[2] Univ Tokyo, Fac Engn, Dept Chem & Biotechnol, Bunkyo Ku, Tokyo 113, Japan

来源：

POLYMER | 1998年 / 39卷 / 17期

关键词：

free volume; positron annihilation lifetime; polysiloxane;

D O I：

10.1016/S0032-3861(97)10380-9

中图分类号：

O63 [高分子化学（高聚物）];

学科分类号：

070305 ; 080501 ; 081704 ;

摘要：

In order to correlate the size, numerical concentration, and size distribution of free volumes with the nanostructure of crosslinked polysiloxane (cured MQ resin), free volumes of polysiloxanes of different degree of crosslinkage polysiloxanes were observed by positron annihilation lifetime measurements in the temperature range from 30 K to room temperature. The free-volume diameters of the highly crosslinked polysiloxane were found to be larger in the temperature range studied and their distributions become broader above T-g (150 K) than those for the lowly crosslinked polysiloxane, whereas free volume contents (number density) were lower for the highly crosslinked polysiloxane. The results suggest the heterogeneous and distorted nanostructure of prepolymers in the highly crosslinked polysiloxane. (C) 1998 Elsevier Science Ltd. All rights reserved.

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页码：4075 / 4079

页数：5

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