LDHs的制备与改性及其在软聚氯乙烯阻燃中的应用

Preparation and modification of LDHs and its assisting flame retardant effect in soft PVC

采用快速成核晶化法合成锌镁铝类水滑石(Zn Mg Al-LDHs),以油酸钠为改性剂对LDHs进行湿法表面改性;通过FT-IR、XRD、FESEM、TG等对改性前后LDHs进行表征;考察改性前后LDHs的添加量对LDHs/软PVC复合材料阻燃及力学性能的影响。结果表明,油酸钠质量浓度为1.75 g/L,改性温度为65℃,改性时间为30 min,改性后LDHs的平均活化指数为99.65%。LDHs/软PVC复合材料的极限氧指数(LOI)值随LDHs添加量的增加而增大,改性后LDHs的阻燃效果明显改善;当LDHs添加量在0~10份(PVC为100份)左右,添加改性后LDHs的复合材料的拉伸强度和断裂伸长率均优于空白样;添加量在10~50份时,复合材料的断裂伸长率和拉伸强度均随着添加量的增加而下降,改性后LDHs的下降趋势明显弱于未改性LDHs。

Zn Mg Al-LDHs layered double hydroxides（ LDHs） is prepared by a rapid nucleation and crystallization method,and is surficial modified by wet method using sodium oleate as modifier. LDHs and modified LDHs both are characterized by FT-IR,XRD,FESEM,TG etc. The influences of the addition amounts of LDHs and modified LDHs on the flame retardant and mechanical properties of LDHs/soft PVC composites are investigated. The results show that the average activation index of modified LDHs is 99. 65%,when the mass concentration of sodium oleate is 1. 75 g·L-1,the modification temperature is at 65℃ and the modification spends 30 min.The limiting oxygen index（ LOI） of LDHs/soft PVC composites increases with the increase of addition amount of LDHs.The flame retardant property of modified-LDHs/soft PVC composites is better than that of LDHs/soft PVC.When the addition amount of LDHs modified or not modified is0% - 10% that of PVC,the tensile strength and elongation at break of modified-LDHs/soft PVC composites are both better than that of the blank samples.When the addition amount of LDHs modified or not modified is 10% - 50%,both the tensile strength and elongation at break of composites decrease with the increase of mass fraction of LDHs,and that of modified-LDHs/soft PVC composites decrease slowly than that of LDHs/soft PVC composites.