Structural characterization of poly(N-isopropylacrylamide) gels and some of their copolymers with acrylamide through positron annihilation lifetime spectroscopy

被引：16

作者：

Sousa, RG

Freitas, RFS

Magalhaes, WF

机构：

[1] Univ Fed Minas Gerais, Inst Exact Sci, Dept Chem, LEAP,Lab Positron Annihilat Spect, BR-31270901 Belo Horizonte, MG, Brazil

[2] Univ Fed Minas Gerais, Sch Engn, Dept Chem Engn, Lab Gels & Polymers, BR-30160030 Belo Horizonte, MG, Brazil

来源：

POLYMER | 1998年 / 39卷 / 16期

关键词：

positron annihilation; free volume; thermoreversible gel;

D O I：

10.1016/S0032-3861(97)10341-X

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 this work, poly(N-isopropylacrylamide) (NIPAAm), poly(acrylamide) (AAm) and poly(N-isopropylacrylamide)-co-acrylamide (NIPAAm/AAm) gels were characterized through positron annihilation lifetime spectroscopy (PALS). PALS was used to determine the average free volume radii of NIPAAm and NIPAAm/AAm gels, through the measurement of the ortho-positronium (o-Ps) Lifetime. NIPAAm gel 10 x 1 showed a radius of approximately 2.9 Angstrom. The copolymers with acrylamide, NIPAAm/AAm 10 x 1, with the acrylamide composition varying from 2 to 100 wt%, showed a decreased radius down to 2.1 Angstrom in AAm 10 x I gel. The free volume estimated for the gels decreases with increasing acrylamide concentration. The results are discussed in terms of the changes in the gels' structure due to different polymer-polymer interactions. (C) 1998 Published by Elsevier Science Ltd. AU rights reserved.

引用

页码：3815 / 3819

页数：5

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