反相气相色谱法研究聚合物共混物的相溶性

Study of the Miscibility of Polymer Blends by Inverse Gas Chromatography

用反相气相色谱法测定了聚氯乙烯(PVC)乙烯醋酸乙烯共聚物(EVA)共混体系中分子间表观热力学相互作用参数χ′23,并以χ′23为判定依据,研究了共混物的相溶性。初步探讨了共混物的组成、聚合物分子链结构、温度与χ′23的关系以及探针分子性质对χ′23参数的影响。结果表明:χ′23值能够准确有效地判定PVC与EVA共混物的相溶性,醋酸乙烯质量分数低的EVA与PVC的共混物是热力学不相溶的;而醋酸乙烯质量分数中等的EVA与PVC的共混物则具有部分相溶性。结果与其它方法得到的结论是一致的。

An investigation was made on the thermodynamic parameters χ ′ 23 of the polymer system polyvinyl chloride (PVC)/ethylene\|vinyl acetate copolymer(EVA) by inverse gas chromatogrphy(IGC), and the miscibility of the blends was studied by using χ ′ 23 as judging foundation, and it was preliminary discussed the relation between χ ′ 23 and composition of the blend, and molecules\|chain structure of polymer, and temperature. The influence of the property of probes on χ ′ 23 was also discussed. Results showed thermodynamic miscibility for PVC/EVA blend was accurately and directly indicated by χ ′ 23 . Experimental data confirmed the conclusion reported by other studies. It was immiscible for blends of which the acetate content was lower in EVA copolymer.The experimental temperature was favorable for improving miscibility of blends. The medium content in EVA copolymer resulted in partial miscibillity for the blend, but the phase\|seperation appeared when the experimental temperature was raised. This is in agreement with the previous studies on polymer blends. The apparent interaction parameter was found to be dependent on the chemical nature of the probe, the values of χ ′ 23 were very different, but most experimental data show the same general trend with temperature and composition of blends.