丙烯酸酯改性聚氨酯水性分散体的结构形态特征

Structure Characterization of Polyurethane Water-Borne Dispersion Modified by Acrylate

利用两种不同的聚合工艺制备得到组成相同的丙烯酸酯改性水性聚氨酯分散体。系列聚合物乳液的存在形态及成膜物结构与聚合工艺有关。丙烯酸改性与乳化同时进行时,其聚合物链结构中软、硬段分布均匀;而采用在溶剂相中改性接枝再乳化分散的方式,分子链中软硬段的微相分离加剧,热稳定性提高。而不同的聚合改性方式对涂膜的耐水性都有明显的改善,只是先聚合改性后乳化的工艺,乳液的贮存稳定性更好。

Acrylate modified water-borne polyurethane dispersions with same compositions were prepared by two different prepolymerization processes. Existence state and film structure of polymer emulsion series were related to polymerization process. Soft and hard segments in polymer chains were well-distributed when acrylate modification and emulsification performed at the same time. When modification graft before emulsion dispersion in solvent was adopted, micro phase separation of soft and hard segments in molecular chains was enhanced greatly and its thermo-stability improved . Different polymerization processes obviously improved film water-resistance, the only difference lay in the fact that the first modification and then emulsification process made store stability of emulsion better.