化学学报 ›› 2002, Vol. 60 ›› Issue (9): 1700-1706. 上一篇    下一篇

研究论文

自组装分子凝胶的原位光聚合及其聚合物研究

黎坚;王理;殷以华;杨亚江   

  1. 华中科技大学化学系,武汉(430074)
  • 出版日期:2002-09-15 发布日期:2002-09-15

Study on situ Photopolymerization of Self-Assembly Molecular Gels and Their Polymers

Li Jian;Wang Li;Ying Yihua;Yang Yajiang   

  1. Department of Chemistry, Huazhong University of Science & Technology,Wuhan(430074)
  • Online:2002-09-15 Published:2002-09-15

合成了一种以二胺为基础的可聚合凝胶因子4,4’-二(α-甲基丙烯酰氧基- 1,3-亚乙氧基羰基丙酰氨基)二苯甲烷(BMDM),利用在特定结构区域的非共价 键相互作用自组装形成有序的三维纤维网络,使有机溶剂凝胶化。并利用紫外光引 发聚合,“锁定”凝胶网络,形成稳定的有序高级结构。光聚合后,分子凝胶的稳 定时间超过1年;而光聚合前,分子凝胶的稳定时间一般只有几天到几十天。由电 镜和偏光显微镜研究的凝胶形态学表明,凝胶中存在由相互缠结的三维纤维网络构 成的球晶。DSC研究表明,未聚合的分子凝胶中球晶结构的解缔(peak 1)须克服 一个势垒,势能为ΔH = 0.8 kJ·mol~(-1),这主要是一种范德华弱相互作用。而 发生的凝胶-溶胶相转变(peak 2),则说明了自组装纤维中BMDM分子间存在氢键 等次价键相互作用。这种次价键能即为凝胶-溶胶相转变热焓ΔH = 22.3 kJ· mol~(-1)。聚合凝胶只有体积相变而无凝胶-溶胶相转变,且聚合凝胶的体积相变 温度要比光聚合前的凝胶-溶胶相转变温度高出约为110 ~ 120 ℃。研究干聚合凝 胶在丙酮中的溶胀特性发现,其溶胀过程遵循二级溶胀动力学,影响该凝胶溶胀行 为的因素主要是交联程度。

关键词: 凝胶, 溶胀, 动力学研究, 晶体, 二苯基甲烷 P

Polymerizable gelator, 4,4'-bis(α-methylacryloyloxy-1,3- ethyleneoxycarbonylpropionamido) diphenyl methane (BMDM) based on binary amine, was prepared and self-assembled into elongated fibers in organic solvents via non-covalent interaction. These fibers are able to aggregate further into three-dimensional networks, causing organic solvents to gelatinize. By photopolymerization of the gelled solution, the scaffoldlike structure of the gels was locked and the gels formed more stable well-ordered superstructure. The stable time of the polymerized gels is more than one year. However, the stable time of the unpolymerized molecular gels is only from several days to several weeks. The studies of polarized optical microscopy and TEM indicate the formation of spherulites undergoing aggregation of self-assembled fibers. It was found by DSC that the potential barrier (ΔH) for disassociation of spherulites formed by van der Waals interaction was 0.8 kJ·mol~(-1) (Peak 1) and the enthalpy (ΔH) of gel-sol phase transition for fiber aggregated by hydrogen bonding was 22.3 kJ·mol~(- 1) (Peak 2). For polymerized gels there is only a volume phase transition, without a gel-sol phase transition. The temperature of volume phase transition for polymerized gels is about 110 ~ 120 ℃ higher than that of the unirradiated gels. Swelling behavior of the dried polymerized gels follows Schott second-order diffusion kinetics. The degree of cross-linking is a main factor influencing the swelling behavior of the gels.

Key words: GEL, SWELLING, KINETIC STUDY, CRYSTALS, DIPHENYLMETHANE P

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