Effect of Melt Temperature and Hold Pressure on the Weld-Line Strength of an Injection Molded Talc-Filled Polypropylene

Yuanxin Zhou, P. K. Mallick
2014 Journal of Composites  
Tensile stress-strain behavior coupled with fractography was used to investigate the weld-line strength of an injection molded 40 w% talc-filled polypropylene. The relationship between processing conditions, microstructure, and tensile strength was established. Fracture surface of the weld line exhibited skin-core morphology with different degrees of talc particle orientations in the core and in the skin. Experimental results also showed that the thickness of the core decreased and the
more » ... ed and the thickness of the skins increased with increasing melt temperature and increasing hold pressure, which resulted in an increase of yield strength and yield strain with increasing melt temperature and increasing hold pressure. Finally, a three-parameter nonlinear constitutive model was developed to describe the strain softening behavior of the weld-line strength of talc-filled polypropylene. The parameters in this model are the modulus E, the strain exponent m, and the compliance factor β. The simulated stress-strain curves from the model are in good agreement with the test data, and both m and β are functions of skin-core thickness ratio.
doi:10.1155/2014/846962 fatcat:3der3kgy7fbrbmi2bjqehqum7y