偏氯乙烯共聚物/层状双金属氢氧化物纳米复合材料的制备与表征

PREPARATION AND CHARACTERIZATION OF VINYLIDENE CHLORIDE COPOLYMER/LAYERED DOUBLE HYDROXIDES NANOCOMPOSITES

通过硝酸根插层层状双金属氢氧化物(LDH)与可逆加成-断裂链转移(RAFT)试剂S,S'-对(α,α'-二甲基-α″-乙酸)三硫代碳酸酯(CTA)阴离子的离子交换制备CTA阴离子插层LDH,再通过原位RAFT活性自由基聚合制备偏氯乙烯-丙烯酸甲酯(VDC-MA)共聚物/LDH纳米复合材料.采用傅里叶变换红外光谱、元素分析和X-射线衍射、透射电子显微镜、凝胶渗透色谱仪和热失重仪表征了CTA阴离子插层LDH和纳米复合材料的结构和性能.结果表明,CTA阴离子可以置换硝酸根阴离子插入到LDH层间,LDH层间距由0.89 nm增大到1.50 nm;在原位RAFT聚合过程中,LDH逐渐剥离,LDH以纳米层板形式分散在VDC-MA共聚物基体中;VDC-MA共聚物数均分子量随加入的插层CTA阴离子含量增加而减小,聚合具有活性特征.此外,含量LDH的引入可明显提高VDC-MA共聚物的热稳定性.

In order to prepare vinylidene chloride-methyl acrylate（VDC-MA） copolymer /layered double hydroxide（LDH） nanocomposites with intercalated or exfoliated LDH structure,reversible additionfragmentation chain transfer living radical polymerization of VDC-MA were carried out in the presence of LDH intercalated with S,S＇-bis（α＇ α-dimethyl-α″-acetic acid）-trithiocarbonate anion groups（CTA-LDH）.The structure and properties of CTA-LDH and VDC-MA copolymer / LDH nanocomposites were characterized by Fourier transform infrared spectroscopy,elemental analysis,transmission electron microscopy,gel permeation chromatography and thermogravimetric analysis.It was found that the layer spacing of LDH changed from 0.89 nm to 1.50 nm as CTA anion groups intercalated into LDH through the ion-exchange reaction.The average molecular weight of VDC-MA copolymers was decreased as the amount of intercalated CTA increased,confirming the＂living＂nature of VDC-MA copolymerizations.LDH could be gradually exfoliated in the process of in situ RAFT polymerization,and dispersed in VDC-MA copolymer matrix in the form of nanolaminates.The TGA data evidenced that the thermal degradation temperatures of VDC-MA copolymer / LDH nanocomposites were increased as the weight fraction of incorporated LDH increased.