摘要
目前微胶囊红磷大多采用原位聚合法制备,工艺较为复杂,使用的囊壳原料可能对环境造成危害。为解决这一问题,本文以可降解材料乙基纤维素(EC)为壁材,无水乙醇为壁材溶剂,蒸馏水为壁材非溶剂,采用相分离法制备微胶囊红磷,并利用FTIR、SEM及XPS表征微胶囊红磷的形态及包覆效果,同时对样品的热稳定性、吸湿性及感度进行测定,以此确定最佳工艺条件。实验结果表明:经EC包覆后的红磷样品表面粗糙,包覆率随乙基纤维素添加量的增多而升高,最高可达94.8%;EC囊壳能有效提高红磷的热稳定性及安定性,降低吸湿率。在保证红磷正常使用不受影响的前提下,取0.6g乙基纤维素、2g红磷为最佳工艺条件,包覆率达93.2%;制备的微胶囊红磷样品热稳定性提高,着火点升高至310℃;10d后吸湿率降低至6.8%,较普通红磷降低约16.8%;微胶囊红磷摩擦感度降至34%,较未处理红磷降低52%。采用相分离法在常温、中性条件下制备EC包覆微胶囊红磷,工艺简便,材料绿色环保,制备的微胶囊红磷样品具有良好的使用性能。
Microencapsulation red phosphorus(MRP) were generally prepared by in-situ method at present. While the preparation process was complex and the shell raw material may do harm to environment. To solve the problem above, biodegradable material ethyl cellulose(EC) was selected as shell material of MRP. Meanwhile, with ethyl alcohol and distilled water serving as solvent and nonsolvent for EC respectively, phase separation method was applied to EC coating MRP preparation. The morphology and encapsulation ratio of MRP were tested by FTIR, SEM and XPS. The thermal stability,water absorption and sensitivity of MRP were also characterized to determine the optimal process conditions. The results indicated that after being encapsulated by EC, MRP exhibited a rougher surface morphology. The encapsulation ratio can reach to 94.8% with the addition of increasing EC. Meanwhile,the introduction of EC shell structure improved the thermal stability and mechanical stability of pristine red phosphorus(RP), while reduced the water absorption. On the premise of the performance of RP being affected least, 0.6 g EC and 2 g RP were selected as the optimal process condition. MRP prepared under such condition got a satisfied encapsulation ratio as 93.2%. Furthermore, the ignition point of the sample increased to 310℃, and the water absorption decreased to 6.8%, reducing by 16.8% compared with RP.The friction sensitivity of MRP decreased to 34%, which was 52% lower than pristine red phosphorus.Phase separation method allowed MRP preparation conducting under a normal temperature and neutral condition, simplifying the technological process. EC was more environmental than traditional organic shell material, and the sample satisfied the needs of practical application.
引文
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