Influence of micro⁃foaming injection molding process on cell structure of glass⁃fiber⁃reinforced PBT products

doi:10.19491/j.issn.1001-9278.2022.05.001

Abstract

Abstract:

A micro?foaming injection molding experiment was performed using glass?fiber?reinforced poly（butylene terephthalate） composites as a material. The apparent density， mechanical properties， cell morphology and structure of the obtained products were investigated using a sponge density tester， a universal chemical testing machine， and a scanning electron microscope. The influence of micro?foaming process parameters on the weight loss ratio and cell structure of the products was investigated. The injection molding process parameters for an ideal cell structure was explored through a comparison of the cell structure and mechanical properties of the products obtained at different weight loss ratios. The results indicated that the gas injection rate and melt temperature were the main factors affecting the weight?loss ratio of the product. For the cell structure， the gas injection rate showed the greatest influence， following with the injection pressure and injection speed. The products obtained a good foam quality and mechanical properties at a gas injection amount of 0.2 wt%， an injection speed of 70 cm³/s， and an injection pressure of 70 MPa.

Key words: glass?fiber?reinforced polybutylene terephthalate, micro?foam injection molding, process parameter, cell structure, mechanical property

CLC Number:

TQ328

SUN Wenbo, XIN Chunling, HE Yadong, ZHAI Yujiao, YAN Baorui. Influence of micro⁃foaming injection molding process on cell structure of glass⁃fiber⁃reinforced PBT products[J]. China Plastics, 2022, 36(5): 1-7.

Figures/Tables 8

水平

熔体温度/

℃

注气量/

注射速率/

cm³·s^-1

Tab.1. Setting of factor and level

Fig.1. Influence of injection process parameters on weight loss ratio of the product

Fig.2. Influence of injection process parameters on average cell size of the product

Fig.3. Influence of injection process parameters on standard deviation of cell size of the product

Fig.4. Influence of injection process parameters on cell density of the product

Fig.5. SEM images of products prepared at different gas injection rates

Fig.6. SEM images of products prepared at different injection speed and pressure

Fig.7. Mechanical properties and bubble structure of products with different weight loss

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