A new microcellular injection molding process for polycarbonate using water as the physical blowing agent

作者：Peng, Jun; Turng, Lih Sheng^*; Peng, Xiang Fang

来源：Polymer Engineering and Science, 2012, 52(7): 1464-1473.

DOI：10.1002/pen.23092

• Dissolved salt
• Distilled water
• Feed-rates
• Injection molded part
• Injection molded plastic
• Microcellular
• Microcellular injection molding
• Molded parts
• Nucleating agents
• Physical blowing agents
• Salt concentration
• Salt crystals
• Smooth surface
• Tensile bar
• Weight reduction

This article presents a new process for producing microcellular injection molded plastic parts using water as the physical blowing agent and micro-scaled particles as the cell nucleating agents. Distilled water with dissolved salt were fed through the hopper of an injection molding machine at a preset rate and mixed with polycarbonate (PC) in the machine barrel. Microcellular PC tensile bars were then injection molded with different shot volumes, water/salt solution feed rates, and salt concentrations. Tiny salt crystals of 10-20 mu m recrystallized during molding acted as nucleating agents in the PC foamed parts. The surface roughness, mechanical properties, and microstructure of the solid and foamed parts were measured and compared with microcellular injection molded parts using supercritical fluid (SCF) nitrogen as the physical blowing agent. At a similar weight reduction of about 10%, the water foamed PC parts have a smooth surface comparable to that of solid injection molded parts. They also possess similar, if not better, mechanical properties compared to SCF nitrogen foamed PC parts. Without the nucleating agent, PC/water foamed parts exhibit much larger and fewer bubbles within the molded parts. POLYM. ENG. SCI., 2012.

• 出版日期2012-7
• 单位华南理工大学