目的 研究不同初始应变率和湿度条件下，淀粉/PP基发泡缓冲包装材料的动态冲击性能，并构建基于湿度及应变率的动态本构模型。方法 应用冲击试验机对淀粉/PP基发泡缓冲包装材料进行不同初始应变率及相对湿度下的动态冲击实验，得到其应力–应变曲线，并构建动态本构模型。结果 动态冲击下，材料的应变率效应较为明显，该材料的应力和能量吸收随着初始应变率的增加而增加。在相对湿度为50%的条件下，当应变为0.6时，随着初始应变率由30 s⁻¹分别增加至34.6、38.6 s⁻¹，材料的应力分别增加了36.1%和50.4%，能量吸收分别增加了25.8%、36.4%。该材料对环境湿度较为敏感，该材料动态冲击力学性能随着相对湿度的增加显著降低，在初始应变率为38.6 s⁻¹条件下，当应变为0.6时，随着相对湿度由50%增加到70%、90%，该材料的应力分别下降了9.7%和11.3%。另外，构建了基于初始应变率和湿度的淀粉/PP基发泡材料的动态冲击本构模型。结论 初始应变率与湿度对材料的缓冲性能有一定的影响。基于初始应变率和相对湿度的动态冲击本构模型，通过实验进行了验证，实验数据和本构模型一致性较好，该本构模型可用于预测该材料的动态冲击应力–应变曲线。

The work aims to study the dynamic impact properties of starch/polypropylene (PP) foam cushioning packaging material under different initial strain rates and relative humidity and construct the dynamic constitutive model based on humidity and strain rate. The stress-strain curves were obtained through the dynamic impact experiments on starch/PP foam cushioning packaging material by impact test machine under different initial strain rates and relative humidity and the dynamic constitutive model was constructed. The effect of strain rate was significant under dynamic impact and the stress and energy absorption increased obviously as the initial strain rate increased. The material stress increased by 36.1% and 50.4% and the energy absorption increased by 25.8% and 36.4% as the initial strain rate increased from 30 s−1 to 34.6 and 38.6 s−1 when the strain was 0.6 under RH50%. The material was sensitive to humidity. The dynamic impact properties declined as the relative humidity increased. The stress decreased by 9.7% and 11.3% as the humidity increased from 50% to 70% and 90% when the strain was 0.6 under initial strain rate of 38.6 s−1. Based on the above analysis, the dynamic impact constitutive model of starch/PP foam cushioning packaging material was constructed based on initial strain rate and relative humidity. The initial strain rate and humidity have a certain impact on the cushioning performance of the material. The dynamic impact constitutive model based on the initial strain rate and relative humidity is verified by experiments. The experimental data are in good agreement with the constitutive model, and the constitutive model can be used to predict the dynamic impact stress-strain curve of the material.