玻纤增强聚酰胺6/次磷酸钇复合材料的制备及其阻燃性能

Preparation of glass fiber reinforced polyamide 6/yttrium hypophosphite composites and their flame retardant properties

以六水合氯化钇(YCl3·6H2O)和次磷酸钠(NaH2PO2)为原料,采用共沉淀法制备了一种新型稀土金属次磷酸盐-次磷酸钇(YHP),对其进行了表征;以YHP为阻燃剂,采用熔融共混法制备了系列玻纤增强聚酰胺6(GFPA)/次磷酸钇复合材料(GFPA/YHP),采用热重、极限氧指数(LOI)、UL-94垂直燃烧和微型量热测试研究了YHP添加量对复合材料热稳定性、阻燃性能及燃烧性能的影响.结果表明,YHP已成功制备,其具有棒状结构,长度为20~100mm,宽度为5~20mm,热稳定性很高,降解温度T5%为410℃,最大热失重速率温度Tmax为412℃,750℃下热解的残炭率为90.8wt%.加入YHP降低了GFPA/YHP复合材料的热分解温度,但提高了其成炭率和高温稳定性,YHP添加量为20wt%时,复合材料的热分解温度为373℃,最大热失重速率温度为414℃,700℃下热解的残炭率为50.42wt%;YHP可有效提高复合材料的阻燃性能,极限氧指数(LOI)达27.5vol%,垂直燃烧级别达UL-94 V-1级;YHP可有效降低复合材料燃烧过程的热释放速率峰值(PHRR)和总放热(THR)量,二者分别降至327 W/g和15.8 kJ/g,比GFPA分别下降了14.1%和25.4%,表明YHP有效降低了GFPA/YHP复合材料燃烧的火灾危险性.

A novel rare earth hypophosphite--yttrium hypophosphite (YHP) was synthesized by co-precipitation method using yttrium(Ⅲ)chloride hexahydrate (YC13·6H2O)and sodium hypophosphite (NaHEPO2)as raw materials,and it was characterized by XRD,FT-IR,SEM and TGA. Furthermore,YHP was used as flame retardant to prepare a series of glass fiber reinforced polyamide 6/yttrium hypophosphite composites (GFPA/YHP)by melting bending method.TG, limiting oxygen index (LOI)test,underwriters laboratories (UL)94(UL-94)testing and microscale combustion calorimetry (MCC)were used to investigate the effects of YHP loading on thermal stability,flame retardany and combustion properties of GFPA/YHP composites.The results showed that YHP was prepared,it presented rod-like structures with a size of 20-100μm in length and 5-20μm in width,and presented high thermal stability with degradation temperature (T5%) of 410℃,maximal mass loss rate temperature (Tmax)of 410℃ and char residue at 750℃ of 90.8wt%.The addition of YHP decreased T5% but increased char residue and thermal stability in high temperature of GFPAfYHP composites. When 20wt% YHP was loaded,GFPA/YHP20 presented T5% of 373℃ with Tmax of 414℃ and char residue at 700℃ of 50.42wt%.YHP could significantly enhance flame retardancy of the composites,GFPA/YHP20(with 20wt% YHP)reached UL-94V-trating with limiting oxygen index (LOI)of 27.5 vo1%.YHP could significantly decrease heat release rate (PHRR)and total heat release (THR)of GFPA/YHP composites in combustion process. PHRR and THR values of GFPA/YHP20were decrease to 327W/g and 15.8kJ/g,which were reduced 14.1% and 25.1% compared with GFPA,indicating YHP could effectively reduce fire hazard of GFPA/YHP composites in combustion process.