BDP阻燃PC／ABS及其纳米复合材料的阻燃性和热降解动力学

Flame Retardancy and Kinetics of Thermal Degradation of Flame Retardant PC/ABS and Its Nanocomposites

采用双螺杆挤出机挤出造粒制备了苯基双酚 A 二磷酸酯(BDP)阻燃的聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯(ABS)、PC/ABS/有机蒙脱土(OMMT)和 PC/ABS/有机改性纳米二氧化硅(SiO_2)_3种复合材料,采用热重分析探讨了 PC/ABS/BDP、PC/ABS/BDP/OMMT 和 PC/ABS/BDP/SiO_2复合材料的热降解动力学行为,以此分析其阻燃性能与热降解行为的关系。结果表明,加入纳米材料后,在质量损失8%以前,PC/ABS/BDP/OMMT 和 PC/ABS/BDP/SiO_2纳米复合材料的活化能均低于 PC/ABS/BDP 的活化能,但质量损失8%以后,PC/ABS/BDP/OMMT 和PC/ABS/BDP/SiO_2复合材料的活化能均高于阻燃 PC/ABS。在质量损失5%～75%范围内,PC/ABS/BDP/OMMT和 PC/ABS/BDP/SiO_2平均活化能分别为139.39 kJ/mol 和144.17 kJ/mol,均高于 PC/ABS/BDP 的平均活化能(104.87 kJ/mol).说明添加纳米材料后,由于 BDP 与 OMMT 或 SiO_2的协同阻燃作用,降低了材料的热降解速率,增大了材料的热稳定性,这与氧指数测试、UL94 V 阻燃性能及热重分析得出的结论一致。

Composites of polycarbonate/acrylonitrile-butadiene-styrene copolymer （PC/ABS）, PC/ABS/ organic montmorillonite （OMMT）, and PC/ABS/organic-modified nano-SiO2（SiO2） flame retarded by bisphenol A all（phosphate phenyl ester）（BDP） were prepared via extrusion and granulation using a twinscrew extruder. By means of TG, their thermal decomposition kinetic behaviors in nitrogen atmosphere were studied. Before 8 % mass loss, the activation energy of the PC/ABS/BDP/OMMT and PC/ABS/ BDP/SiO2 nancomposites was lower than that of PC/ABS/BDP. However the opposite was observed after 8 % mass loss. The average activation energy of PC/ABS/BDP/OMMT and PC/ABS/BDP/SiO2 were 139.39 kJ/mol and 144.17 kJ/mol in 5 % -75 % mass loss, respectively, all greater than that of PC/ABS/BDP（104.87 kJ/mol）. It was found that with OMMT or SiO2 added, the thermal decomposition speed of PC/ABS/BDP decreased and the thermal stability increased, as confirmed by the measure- ments of TG, limiting oxygen index, and UL94 V flame retardancy.