Effects of injection molding process parameters on the chemical foaming behavior of polypropylene and polystyrene

Chen Yuan Chung, Shyh Shin Hwang, Shia Chung Chen, Ming Chien Lai

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

In the present study, semi-crystalline polypropylene (PP) and amorphous polystyrene (PS) were adopted as matrix materials. After the exothermic foaming agent azodicarbonamide was added, injection molding was implemented to create samples. The mold flow analysis program Moldex3D was then applied to verify the short-shot results. Three process parameters were adopted, namely injection speed, melt temperature, and mold temperature; three levels were set for each factor in the one-factor-at-a-time experimental design. The macroscopic effects of the factors on the weight, specific weight, and expansion ratios of the samples were investigated to determine foaming efficiency, and their microscopic effects on cell density and diameter were examined using a scanning electron microscope. The process parameters for the exothermic foaming agent were optimized accordingly. Finally, the expansion ratios of the two matrix materials in the optimal process parameter settings were compared. After the experimental database was created, the foaming module of the chemical blowing agents was established by Moldex3D Company. The results indicated that semi-crystalline materials foamed less due to their crystallinity. PP exhibits the highest expansion ratio at low injection speed, a high melt temperature, and a low mold temperature, whereas PS exhibits the highest expansion ratio at high injection speed, a moderate melt temperature, and a low mold temperature.

Original languageEnglish
Article number2331
JournalPolymers
Volume13
Issue number14
DOIs
StatePublished - 2 Jul 2021

Keywords

  • Amorphous material
  • Exothermic chemical foaming agent
  • Foam injection molding
  • Semi-crystalline material

Fingerprint

Dive into the research topics of 'Effects of injection molding process parameters on the chemical foaming behavior of polypropylene and polystyrene'. Together they form a unique fingerprint.

Cite this