阳离子型PDMS/PU无皂微乳液膜的结构与性能

在催化剂和助溶剂的作用下,采用一步法,以端羟基聚二甲基硅氧烷(PDMS)/聚醚二醇(PTMG)为软段,异佛尔酮二异氰酸酯(IPD I)为硬段(三羟甲基丙烷TMP为交联剂、N-甲基二乙醇胺MDEA为扩链剂)合成了一系列自乳化双软段PDMS/PU微乳液。将乳液流延成膜,综合研究了PDMS/PU中软硬段比例、溶剂、软段相对分子质量、TMP用量、MDEA用量、PDMS含量对成膜力学性能和耐水性的影响。结果表明,当n(NCO)/n(OH)=2.2,PTMG的相对分子质量为1 000,w(TMP)=3%,w(MDEA)=40%,w(PDMS)=15%,PDMS/PU膜的附着力为1级,光泽度101%,硬度H,耐冲击性50 cm,抗张强度33.8 MPa,柔韧性1级,胶膜吸水率随着w(PDMS)的增加,由11.2%降低到0.12%。

Structure and Properties of Cationic Polyurethane/Polydimethylsiloxane Surfactant-free Micro Emulsion Membranes

Under the action of catalyst and cosolvent,a series of hydroxyl-terminated polydimethylsiloxane(PDMS) based polyurethane(PU) micro emulsion were successfully prepared by surfactant-free copolymerization.They were prepared by reacting isophorone diisocyanate(IPDI),poly(tetramethylene glycol)(PTMG) and polydimethylsiloxane(PDMS) with N-methyldiethanolamine(MDEA) as chain extender and trimethylolpropane(TMP) as crosslinker.After neutralization with dimethyl sulfate and inverse emulsion polymerization with deionized water,a series of micro emulsions were obtained.The emulsions were then cast into membranes named as PDMS/PU.Tests of mechanical properties and water absorption of PU-PDMS were carried out,and the effects of the content of hard segment,solvent,TMP,MDEA,PDMS and the molecular weight of soft segment on the properties were investigated.It is noticed that these properties are enhanced in the PDMS/PU membranes compared with pure PU,which confirm that PU is de-blocked and end-capped with PDMS.When n(NCO)/n(OH)=2.2,M_n(PTMG)=1 000,w(TMP)=3%,w(MDEA)=40%,w(PDMS)=15%,the adhesive force grade and flexility of the membranes could reach the 1st level,glossiness 101%,hardness over H,resistance to shock 50 cm and tensile strength 33.8 MPa.It is also noticed that the water absorption decreases from 11.2% to 0.12% with the increase of w(PDMS).