含磷超支化聚合物共混改性PA6的性能研究

摘要

以尼龙(PA)6为基体树脂，含磷超支化聚酰胺(HBPA)为改性剂，通过熔融挤出制备了PA6/HBPA共混物。采用毛细管流变仪、力学性能测试、极限氧指数(LOI)测试及热重(TG)分析研究了HBPA含量对共混物流变性能、力学性能和阻燃性能的影响。结果表明，随HBPA含量的增加，共混物熔体的非牛顿指数逐渐接近于1，熔体向牛顿流体转变；熔体表观黏度下降，加工性能得到改善；熔体黏流活化能增大，对温度的敏感性变强。加入少量的HBPA能够提高PA6的力学性能，当HBPA质量分数为0.5%时共混物拉伸强度最大，由纯PA6的62.6 MPa增加到72.4 MPa，当HBPA质量分数为1%时，断裂伸长率和缺口冲击强度最大，分别由纯PA6的228.3%和19.8 kJ/m2提高到284.7%和24.5 kJ/m2。LOI测试和TG分析表明，HBPA可通过促进凝聚相成炭，提高PA6的阻燃性，当HBPA质量分数为1.5%时，共混物的LOI最大，达到28.4%。%Blends of polyamide (PA) 6 and phosphorous-containing hyperbranched polyamide (HBPA) were prepared by melt extrusion with PA6 as matrix and HBPA as modifier. The rheological behaviors,tensile and impact properties and flame resistance of the blends were investigated through capillary rheometer,mechanical properties tests,LOI test and TG analysis . The results show that with the content of HBPA increasing,the non-Newtonian index of the blend melt is close to 1 gradually and the melt tends to be converted to Newtonian fluids,the apparent viscosity decreases and it indicates that the processing property of the blend is improved,the viscous flow activation energy increases and it indicates that the temperature sensitivity of the blend is enhanced. Adding a small amount of HBPA can improve the mechanical properties of the blend,when the mass fraction of HBPA is 0.5%, the tensile strength is highest and increases from 62.6 MPa of pure PA6 to 72.4 MPa,when the mass fraction of HBPA is 1%,the elongation at break and notched impact strength is highest and increases from 228.3%of pure PA6 to 284.7%and from 19.8 kJ/m2 to 24.5 kJ/m2 respectively. The LOI test and TG analysis show that HBPA can improve the flame resistance of PA6 by promoting condensed phase charring,and when the mass fraction of HBPA is 1.5%,the value of LOI is highest and up to 28.4%.