原位聚合法制备聚氨酯/蒙脱土复合材料研究

摘要

采用原位聚合方法制备了蒙脱土( MMT)在聚氨酯(PUR)基体内呈不同分散状态的PUR/MMT复合材料.PUR预聚反应结束后加入MMT制备的PUR/MMT,MMT片层间距增大,基本以插层状态存在；利用异氰酸酯与MMT上的羟基官能团反应,使部分PUR分子链的硬段部分连接在MMT片层之上,可以使MMT片层在PUR基体内几乎完全剥离、更加均匀地分散.MMT连接在PUR分子链的硬段上,使MMT片层与PUR硬段相区之间的相互作用更强、对PUR软段相区的影响减弱,促使PUR软硬段两相之间出现更大程度的微相分离,导致了材料软段结晶温度的降低和力学性能的提高.%Two types of polyurethane/montmorillonite (PUR/MMT) nanocomposites with different disperssion conditions of silicate layers were prepared via in situ polymerization technology. The MMT added after prepolymerization could not disperse effectively and led to mostly intercalated nanocomposites, while the toluene diisocynate (TDI) of hard segment in PUR matrix grafted on the surface of the silicate layers before polymerization (named it as T-MMT PUR), The MMT showed a nearly full exfoliated structure and well dispersed in PUR matrix, which were due to the improvement of the dispersion and interfacial interaction between PUR chains and silicate layers of T-MMT PUR nanocomposites. The silicate layers grafted on the hard segment of the T-MMT PUR nanocomposites, enhanced the interaction between hard segment and the silicate layers, as well as weaken the interaction between soft segment and the silicate layers, which led to the intensifying of the phase separation between the soft segment and hard segment, and further caused the enhancement of mechanical properties and decrease of soft segment crystallization temperature.