注塑成型制品熔接痕强度预测方法的研究

Research on Forecasting Methods of Weld Line Strength of Injection-molded Parts

分析了注塑制品熔接痕的结构特点,确定弱黏结是影响熔接痕强度的最重要因素;利用Fick扩散定律描述两聚合物熔体前沿接触界面处的分子链扩散运动,用SL格子流体理论计算两聚合物熔体的混合自由能,用Guggenheim经验公式计算两熔体前沿接触界面的表面自由能,建立了无定型聚合物注塑制品的熔接痕的强度预测模型。哑铃试样的强度实验表明:用该数学模型计算的熔接痕的黏结度与实验结果基本吻合。所建立的模型可作为在实际生产中有效的预测工具。

By detailed analyses,this paper concludes that the weak bonding is the main factor that reduces the mechanical properties of the parts. The Fick's diffusion law was used to describe the diffusion of the molecular chains. Sanchez-Lacombe( SL) 's theory for lattice fluid was applied to calculate the mixing energy of two melts. The empirical formula by Guggenheim was used to calculate the free energy of the interface of the two melts. Finally,the prediction model of weld line in the injection-molded parts of amorphous polymers is presented. The tensile strength of the dumbbell specimens was tested. The results showed that the computed results of degree of bonding werewellcoincidewith the experiment results. The model established in this papercan be applied to predict the tensile strength of the weld line in the injection-molded parts of amorphous polymers.