Morphology Development in the Gate Region of Microinjection-Molded Thermoplastics

被引:17
|
作者
Chu, Jing-Song [1 ,2 ,3 ]
Kamal, Musa R. [1 ,2 ]
Derdouri, Abdessalem [4 ]
Hrymak, Andy [5 ]
机构
[1] McGill Univ, Dept Chem Engn, Montreal, PQ, Canada
[2] McGill Univ, CREPEC, Montreal, PQ, Canada
[3] Micromolding Solut, Boucherville, PQ, Canada
[4] Natl Res Council Canada, Inst Ind Mat, Boucherville, PQ, Canada
[5] McMaster Univ, Dept Chem Engn, Hamilton, ON L8S 4L7, Canada
来源
POLYMER ENGINEERING AND SCIENCE | 2012年 / 52卷 / 04期
关键词
OFF TIME; INJECTION; POLYPROPYLENE; POLYETHYLENE; ORIENTATION; FLOW;
D O I
10.1002/pen.22143
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
The melt experiences extremely high shear rates as it travels through the very small gate, in the microinjection molding process. The combination of the high shear rates, extensive viscous heating, and the large thermal gradients has a profound influence on the characteristics of the moldings. However, many of these interactions are not clearly understood. In this study, the morphology of moldings in the gate region was observed using a polarized light microscope. Moreover, the specimens from different regions of micromoldings were analyzed using a differential scanning calorimeter (DSC). Two materials were selected for the study: polyoxymethylene (POM) and high-density polyethylene. Three special morphological features were observed in the gate region for POM but not for polyethylene. The results obtained using the DSC were explained in light of the microstructural features observed using polarized light microscopy. POLYM. ENG. SCI., 52:787-794, 2011. (C) 2011 Society of Plastics Engineers
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页码:787 / 794
页数:8
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