含磺酸根和羧酸根的高固含率聚氨酯分散体稳定性的研究

以聚醚多元醇为软段、甲苯二异氰酸酯为硬段、1,2-二羟基-3-丙磺酸钠(DHPS)和2,2-二羟甲基丙酸(DMPA)为复合亲水扩链剂,合成了聚氨酯(PU)分散体;采用FTIR方法对PU分散体的结构进行了表征;考察了PU分散体的pH稳定性、耐电解质性能、耐高温性、抗冻融性及储存稳定性。实验结果表明,PU分散体的耐电解质性能随反应体系中m(DHPS)∶m(DMPA)的增大而下降;当反应体系中0.4≤m(DHPS)∶m(DMPA)≤0.6时,合成的PU分散体的固含率大于70%(w),PU分散体在pH=5～10的条件下能稳定存在,80℃时稳定性好,室温下放置6个月以上无明显的分层,经4次冻结-融化后产生凝胶。PU分散体具有较好的pH稳定性、耐高温性、抗冻融性及储存稳定性。

Stability of Polyurethane Dispersoid with High Solid Content Containing Sulfonic Group and Carboxylic Group

Polyurethane(PU) dispersoids containing sulfonic groups and carboxylic groups with high solid content were synthesized from poly(tetrahydrofuran-co-propylene oxide)glycol and toluene isocyanate with 1,2-dihydroxy-3-propanesulfonic sodium(DHPS)and dimethylol propionic acid(DMPA) as the composite hydrophilic chain-extender.The PU dispersoids were characterized by means of FTIR.Electrolyte resistance,pH stability,thermal resistance,free-thaw stability and storage stability of the PU dispersoids were investigated.The results showed that the electrolyte resistance of the PU dispersoids decreased with the increase of m(DHPS)∶m(DMPA);when m(DHPS)∶m(DMPA) in the reaction system was between 0.4 and 0.6,the synthesized PU dispersoids with more than 70%(w) solid content could keep stable at pH 5-10;at temperature 80 ℃,the storage period could reach more than 6 months;and it would gelate after freeze-thaw for 4 times.