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将纳米TiO2与低密度聚乙烯(LDPE)复合形成包膜液,采用喷动流化床包膜设备制备了纳米TiO2-LDPE复合材料包膜控释肥。在水浸泡法研究控释肥养分释放特征的基础上,对人工加速老化条件下光照不同时间的控释肥残膜进行失重率测定。采用FT-IR、DSC和黏度法等分析了纳米TiO2对控释肥残膜光催化降解特性的影响,探讨了残膜在光照前后的分子量和羰基指数等的变化规律。结果表明:光催化剂加入后,控释肥的养分释放速率降低且释放期变长;疏水纳米TiO2对控释肥残膜的降解具有显著的促进作用,当添加的质量分数为1%时,降解性能最好。随着残膜的降解程度增大,残膜中LDPE的羰基指数和结晶度升高,黏均分子量下降。
The nanometer TiO2 and low density polyethylene (LDPE) were compounded to form the coating liquid, and the nanometer TiO2-LDPE composite coated controlled release fertilizer was prepared by the spouted fluidized bed coating equipment. Based on the water immersion method to study the nutrient release characteristics of controlled release fertilizers, the weight loss rate of controlled release fertilizers at different time under artificial accelerated aging conditions was measured. The effects of nano-TiO2 on the photocatalytic degradation of controlled release film were analyzed by FT-IR, DSC and viscometry. The changes of molecular weight and carbonyl index before and after light film were discussed. The results showed that after the addition of photocatalyst, the release rate of controlled release fertilizer decreased and the release period became longer. Hydrophobic nano-TiO2 promoted the degradation of controlled release film significantly. When the mass fraction was 1%, the degradation The best performance. With the increase of the residual film degradation, the LDPE carbonyl index and crystallinity increased, the viscosity average molecular weight decreased.