粒料法合成聚氨酯分散体及性能的研究

以聚四氢呋喃二醇(PTMG)为软段,异氟尔酮二异氰酸酯(IPDI)和1,4-丁二醇(BDO)为硬段,二羟甲基丙酸(DMPA)为亲水单体,采用粒料法合成了聚氨酯离子聚合物粒料,制备了固含量为40%的聚氨酯分散体(PUD),研究了亲水含量和硬段含量对分散体性能及其胶膜性能的影响。PUD的ζ电位处于30~60 mV,黏度小于1100 mPa s。随着亲水含量增加,平均粒径减小,粒径分布变窄,黏度升高;硬段含量增加,平均粒径增大,粒径分布变宽,黏度降低。透射电镜显示,溶胶粒子呈大小不一的球形结构。PUD胶膜吸水率在3.15%~6.67%。力学性能测试表明硬段含量增加,断裂伸长率降低,拉伸强度增强。DMA测试显示胶膜出现相分离,有硬段和软段两个玻璃化转变温度。随着硬段含量增加,相分离程度提高,软段玻璃化温度降低,硬段玻璃化温度升高。

Sythesis and Properties of Polymerthane Dispersions Synthesized by Pellet Process

Polyurethane ionomeric polymer pellets were synthesized by the pellet process with polytetramethylene glycol(PTMG) as soft segment,isophorone diisocyanate(IPDI) and 1,4-butanediol(BDO) as hard segments,and dimethylolpropionic acid(DMPA) as hydrophilic monomer,and the polyuerthane dispersion(PUDs) with solid content about 40% were obtained.The properties of PUDs and their films were characterized,and the results show that the Zeta potentials of PUDs are between-30 mV and-60 mV and the viscosity less than 1100 mPa s.With the increase of hydrophilic group content,the average particle size decreases,the particle size distribution narrows and the viscosity increases;while the average particle size decreases,the particle size distribution becomes broader and the viscosity decreases when hard segment content increases.TEM micrographs show that the sizes of the spherical shape pellet particles are nonuniform.Water absorption ratio of all the PUDs films are between 3.15% and 6.67%.The results of tensile tests reveal that the ultimate elongation of PUDs films decreases and tensile strength increases with the increase of hard segment content.Moreover,the DMA dynamic mechanical analysis shows that PUD films have two glass transition temperatures of soft segment glass transition temperature and hard segment glass transition temperature.As the hard segment content is increased,the degree of phase separation is increased,the soft segment glass transition temperature is lowered,and the hard segment glass transition temperature is elevated.