目的开发一种绿色环保、简便高效的微胶囊红磷制备及改性工艺。方法以无水乙醇为溶剂,水为非溶剂,乙基纤维素为囊壳材料,采用相分离法制备乙基纤维素微胶囊红磷(ECRP)。在此基础上,以正硅酸乙酯(TEOS)作为改性剂,采用溶胶凝胶法制备Si O2/EC复合囊壳微胶囊红磷(Si-ECRP)。通过改变TEOS的添加量制备多组Si-ECRP样品,对样品进行形态表征及性能测试,探究最佳工艺条件。结果采用相分离法制备了ECRP,样品包覆效果良好,包覆率为86.5%。10 d后,ECRP的吸湿率降至6.8%,相对于红磷24%的吸湿率,具有明显改善。ECRP的热稳定性和安定性提高,着火点上升至300℃,摩擦感度降至34%。随着TEOS添加量的增加,三组Si-ECRP囊壳结构由Si O2/EC复合结构向SiO2-EC双层包覆结构过渡。选取1m LTEOS添加量作为最佳工艺条件,此时囊壳呈复合结构,样品包覆率达94.2%,着火点较ECRP样品提高100℃,摩擦感度较ECRP下降14%,低至20%,具有更优异的使用性能。结论采用相分离法制备ECRP样品,整个工艺流程在常温、中性条件下进行,原料绿色环保,工艺简便高效。利用乙基纤维素的成壳机理,简化了溶胶凝胶法改性工艺,制备了SiO2/EC复合囊壳结构,微胶囊红磷的安定性能得到进一步提升。
The work aims to develop an eco-environment and efficient microencapsulated red phosphorus preparation and modification method. Ethyl alcohol and distilled water were used as solvent and non-solvent respectively and ethyl cellulose was selected as shell material to prepare microencapsulated red phosphorus(ECRP) by phase separation method. Then, tetraethoxysilane(TEOS) was introduced as the modifier to prepare SiO2/EC composite shell microencapsulated red phosphorus(Si-ECRP) by sol-gel method. Several groups of Si-ECRP samples were prepared by changing the addition of TEOS and the morphology and performance of the samples were characterized to determine the optimal process condition. ECRP prepared by phase separation method had good coating effects and possessed a coating ratio of 86.5%. The moisture ratio after 10 days decreased to 6.8% and improved obviously when compared with the ratio of pristine red phosphorus of 24%. The thermal and mechanical stability of ECRP increased, the ignition point reached 300 ℃ and the friction sensitivity decreased to 34%. As the addition of TEOS increased, the shell structure of three groups of Si-ECRP transferred from composite to double-layer. When 1 m L TEOS was used as the optimal condition, Si-ECRP got a composite shell material and the coating ratio was 94.2%. The ignition point of Si-ECRP was 100 ℃ higher than that of ECRP. The friction sensitivity of Si-ECRP decreased by 14% and reached 20%. Therefore, Si-ECRP had more excellent properties. ECRP can be prepared by phase separation method under normal temperature and neutral environment. In addition, the raw materials are all environmental materials and the method is simple and efficient. On the basis of ethyl cellulose shell forming mechanism, the Si-ECRP preparation process is simplified and SiO2/EC composite shell structure is prepared, so the performance of pristine has been improved further.
microencapsulated red phosphorus
phase separation method