包膜尿素用无溶剂反应成膜的结构调控与性能

Structure control and property of solvent-free reactive layer for coated urea

摘要:

选用三乙醇胺对无溶剂反应成膜的多亚甲基多苯基多异氰酸酯（PAPI）与聚酯多元醇体系进行化学交联改性，以获得尿素包膜材料。通过溶胀率实验、差示扫描量热（DSC）、热重（TG/DTG）及衰减全反射傅里叶变换红外光谱（ATR-FTIR）对膜材的交联密度、结晶形态、热稳定性、分子结构分别进行了表征，并考察了三乙醇胺质量分数对包膜尿素的控释性能的影响。结果表明，三乙醇胺质量分数越大，膜材的交联密度越大、玻璃化转变温度越高。膜材中羰基的氢键化程度在三乙醇胺加入后降低，而-CH2弯曲振动吸收峰增强。当膜材中三乙醇胺的质量分数为2.6%时，包膜尿素的控释期比未改性前至少延长了25天。

Abstract:

Triethanolamine (TEA) was used to modify solvent-free reactive layer of polyaryl polymethylene isocyanate (PAPI) and polyester polyol system for obtaining coated urea. The crosslink density, crystallization morphology, thermal stability and molecular structure of the films were characterized by the swelling method, differential scanning calorimetry (DSC), thermal gravimetric analysis (TG/DTG) and attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR), respectively. And the effect of the mass fraction of TEA on controlled-release property of coated urea was investigated. The results showed that the crosslink density and glass transition temperature of the film increased with the increase in mass fraction of TEA. The degree of hydrogen bonding of carbonyl groups in the film was reduced after TEA was added, but the CH2 bending vibration absorption was enhanced. When the mass fraction of TEA was 2.6%，the control release duration of coated urea was extended by at least 25 d, compared with coated urea without modification treatment.