PC/PPSQ复合物流变行为与阻燃性能研究

Study on Rheological Behavior and Flame-Retardant of PC/PPSQ Composites

自制的梯形硅倍半氧烷(PPSQ)与聚碳酸酯(PC)通过双螺杆挤出机熔融共混制得测试样品。利用应力控制流变仪分析了PC/PPSQ复合物的流变行为;利用锥形量热仪、FTIR和应力控制流变仪分析了复合物的凝聚相结构和组成。PC/PPSQ复合物的流变测试结果显示,在角速度(ω)低于0.1 rad/s时,PC/PPSQ复合物的储能模量要远高于PC的储能模量,当PPSQ含量超过4%时,熔体表现出类固行为;复合物的损耗模量低于PC的损耗模量,同时复数黏度有所降低,且表现出切力变稀的流体行为;随着PPSQ含量的增加,复合物的复数黏度逐渐升高,当含量超过10%时,表现出近似牛顿流体;复合物燃烧性能结果表明,PPSQ的添加使得PC的热释放速率峰值从411 kW/m^2降到243 kW/m^2,热释放总量从86.5 MJ/m^2降至45.5MJ/m^2,烟释放总量从2 149m^2/s降至1 124 m^2/s;隔热性能结果表明,底部温度要远低于表面温度,复合物燃烧过程中形成的炭层能够显著起到隔热作用;PC/PPSQ复合物凝聚相分析结果表明,炭层外部主要由O—Si—O组成,内部主要由无机碳组成;PC/PPSQ复合物炭层强度结果表明,炭层强度较高,炭层致密均匀。

The self-made trapezoidal silsesquioxane(PPSQ)and polycarbonate(PC)were melt blended by twin screw extruder to prepare test samples.The rheological behavior of PC/PPSQ composite was analyzed by stress-controlled rheometer,and the structure and composition of the condensed phase were analyzed by cone calorimeter,FTIR and stress-controlled rheometer.The rheological test results of PC/PPSQ composites show that the storage modulus of PC/PPSQ composites is much higher than that of PC when the angular velocity(ω)is lower than 0.1 rad/s.When the content of PPSQ exceeds 4%,the melt exhibits solid-like behavior.The loss modulus of the composite is lower than that of PC,while the complex viscosity decreases and the shear thinning behavior of the fluid is observed.With the increase of PPSQ content,the complex viscosity of the composite increases gradually,and when the content of PPSQ exceeds 10%,it shows a similar Newtonian fluid.The combustion performance of the composites showes that the peak heat release rate of PC decreases from 411 kW/m^2 to 243 kW/m^2,the total heat release rate decreases from 86.5 MJ/m^2 to 45.5 MJ/m^2,and the total smoke release rate decreases from 2 149 m^2/s to 1 124 m^2/s with the addition of PPSQ.The results of thermal insulation show that the bottom temperature is much lower than the surface temperature,and the carbon layer formed during combustion of the composite can play an important role in thermal insulation.The results of condensed phase analysis of PC/PPSQ composites show that the outer structure of the carbon layer is mainly composed of O—Si—O and the inner part of the carbon layer is mainly composed of inorganic carbon.The results of PC/PPSQ composite carbon layer strength show that the carbon layer strength is higher and the carbon layer is compact and uniform.