Abstract: The effect of annealing on the mechanical and dynamic mechanical properties of injection mold polycarbonate part has been investigated. The results revealed that the residual stress of the polycarbonate injection products tend to reduce due to rearrangement of orientation molecular chains by annealing. Mechanical properties of the products were improved except breaking elongation, with yield strength increased by 14.86%, flexural strength by 12.7%, flexural modulus by 21.27%, impulse strength by17.93%. Dynamic mechanical analysis showed that distortion temperature was increased and residual stresses existed in the products. The change trend of storage modulus of annealed products with scanning temperature was smoother and steadier than that of unannealed products due to molecule chains relaxation. Residual stress in the products changed with scanning frequency at a range of 35HZ to 60HZ during frequency scanning. Residual stress in the products changed with scanning frequency at a range of 35HZ to 60HZ during frequency scanning. Due to residual stresses reducing, the capable of responding to residual stresses was decreased during the scanning temperature increasing.

Key words: annealing, mechanical property, dynamic mechanical property

摘要： 本文研究了聚碳酸酯（Lexan OQ2720）注塑制品退火后的力学及动态力学性能的变化。结果表明，制品的应力集中情况有明显改善，力学性能除断裂伸长率外都产生了较高提升，拉伸强度提高了14.86%，弯曲强度提高了12.7%，弯曲模量提高了21.27%，冲击强度提高了17.93%；动态力学分析结果表明，，注塑制品的内部存在应力。经退火后，注塑制品内部取向、缠结的分子链得到充分松弛，制品储能模量随温度的变化呈线性规律，内部链段的状态稳定，热变形温度得到了提高。而未退火试样的储能模量随温度变化起伏不定，内部链段的状态比较活跃。动态频率对制品中应力有一定响应能力，响应频率范围约为30-60Hz，随着频率扫描温度的升高，由于应力集中降低，频率对应力响应能力不断降低。

关键词: 退火, 力学性能, 动态力学性能