摘要
在聚合物发泡中,CO2气体的浓度分散和扩散速率与初始气泡形态有关。用可视化方法,对挤出条件下CO2气体注入静、动态流场以及气体在高压和低压注入时的气泡形态和破碎问题的研究。研究表明气体小流量时,静态熔体中球形气泡形成、直径长大定型、长度不断伸长的3个阶段与动态熔体中的初始球形膨胀,头部变尖、中间涨大,尾部颈缩及断裂3个阶段有所不同;新型螺杆对气泡破碎和分离作用比收敛流道更有效。高压下,符合实际生产的气体大流量以射流注入螺槽,形成气熔混合的蜂窝状泡沫,促进了气泡的破裂和分散,加强了气体浓度分散和扩散,有助于聚合物/CO2均相溶液的形成。
The changes of bubble interfacial morphology in the processing of extrusion using video recording were investigated respectively when CO2 gas is injected into static or dynamic polymer melt at the low or high gas pressure. The process of single bubble formation in the static and dynamic polymer melt shows three stages,in which the spherical bubble is formed, the bubble grows up in diameter, and then the length of bubble continuously elongated. But, there are some different between them. New type screw is more effective for gas breaking up and separating. At high gas flow rate and high pressure, the jet flow of gas injecting into screw channel promotes bubble rupture and dispersion. When completing this first partial mixing of gas with melt,the agglomerate of honeycomb foam can be got. Through mixing in screw channel, and blending in the mixing segment of new type screw again, the bubble dispersion,and diffusion rate of C02 gas into polymer melt are increased largely.
出处
《轻工机械》
CAS
2006年第1期19-22,共4页
Light Industry Machinery
