二羟甲基丙酸对聚酯型水性聚氨酯性能的影响

Effect of 2,2-DimethyloIpropionic Acid on Properties of Waterborne Polyurethane

采用预聚体法,以聚酯多元醇、甲苯二异氰酸酯、二羟甲基丙酸(DMPA)为原料制备了聚酯型水性聚氨酯乳液,考察了亲水扩链剂 DMPA 用量对水性聚氨酯乳液的稳定性、微粒粒径、运动黏度、抗电解质能力及其胶膜的吸水性和力学性能的影响,并采用广角 X 射线衍射、热重分析对水性聚氯酯胶膜进行了表征。实验结果表明,随 DMPA 用量的增加,水性聚氨酯乳液的稳定性提高、微粒粒径减小、运动黏度增大、抗电解质能力增强,胶膜的吸水性增加,拉伸强度和有序性提高,但胶膜的断裂伸长率和热稳定性有所降低,DMPA 用量(质量分数)为7%～8%较适宜。

Polyester type of waterborne polyurethane emulsions with different contents of 2,2- dimethylolpropionic acid（DMPA） were prepared from polyester polyol, toluene-2,4-diisocyanate and DMPA by prepolymerization. Effect of addition amount of DMPA, used as hydrophilic chain extending agent, on stability, particle size, kinematic viscosity and anti-electrolyte ability of emulsions, and water absorption and mechanical properties of membranes obtained from emulsions were investigated. The membranes were characterized by means of WAXD and thermal gravity analysis. Along with the increase of DMPA content, stability, kinematic viscosity and anti-electrolyte ability of polyurethane emulsions improved, but the particle size decreased. Similarly tensile strength and structural order of relevant membranes improved, but water resistance, elongation at break and thermal stability decreased. Suitable mass fraction of DMPA is 7% -8%.