International Journal of Plastics Technology

, Volume 21, Issue 2, pp 351–369 | Cite as

Improvements on the tensile properties of microcellular injection molded parts using microcellular co-injection molding with the material combinations of PP and PP-GF

  • Edward Suhartono
  • Shia-Chung Chen
  • Kuan-Hua Lee
  • Kuo-Jui Wang
Research Article


One of the drawbacks of microcellular injection molded parts is lower part tensile strength and stiffness than solid parts. This is caused by a reduction in the effective cross-section area as the microcellular structure is generated inside the part. This study investigated how microcellular co-injection molding can add a solid skin layer, encapsulating the foamed core layer, to increase both part strength and stiffness. In addition to PP, PP-GF (10-wt% GF) was used for the reinforcing effect. The experiment used constant injection parameters and varied material combinations, and conventional, MuCell, and co-injection molded parts acted as comparators. The weight reduction was measured to ensure successful microcellular structure generation. The results show that microcellular co-injection molded PP/PP-GF (skin/core) is the optimal combination, reducing weight by 4.2% over co-injection PP/PP-GF, improving yield strength by 18.2% and Young’s modulus by 2.5% over MuCell PP-GF, yet with a brittle strain at break of 0.084 mm/mm.


Co-injection molding Microcellular injection molding Tensile strength 


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Copyright information

© Central Institute of Plastics Engineering & Technology 2017

Authors and Affiliations

  • Edward Suhartono
    • 1
    • 2
  • Shia-Chung Chen
    • 1
    • 2
  • Kuan-Hua Lee
    • 1
    • 2
  • Kuo-Jui Wang
    • 1
    • 2
  1. 1.Department of Mechanical EngineeringChung Yuan Christian UniversityTaoyuan CityTaiwan
  2. 2.R&D Center for Mold and Molding TechnologyChung Yuan Christian UniversityTaoyuan CityTaiwan

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