聚氯乙烯/热塑性聚氨酯共混合金的静动态力学性能及微观结构分析

Static and Dynamic Mechanical Properties and Microstructure Analysis of Polyvinyl Chloride/Thermoplastic Polyurethane Blended Alloy

为了揭示聚氯乙烯(PVC)/热塑性聚氨酯(TPU)共混合金的静动态力学性能以及微观结构对共混体系力学性能的影响,采用万能材料试验机和分离式霍普金森压杆(SHPB)实验装置对PVC/TPU合金开展准静态、动态力学性能实验,获取了较宽应变率范围(0.001~5800 s^(-1))内的应力-应变曲线,并通过傅里叶变换红外光谱(FTIR)及扫描电镜(SEM)对PVC/TPU合金微观结构进行表征。结果表明,材料在准静态拉伸及动态压缩下均具有显著的应变率强化效应。共混比会影响其微观结构及力学性能,共混比为90/10(PVC/TPU)时,材料弹性模量、峰值应力及断裂伸长率最高,且两相相容性最好;随着TPU占比增加,材料的拉伸与压缩力学性能下降,两相之间出现明显的界面层;此外,共混比为50/50时,材料相结构较为复杂,出现双连续相与“海-岛”结构共存的复杂形貌。

To reveal the static and dynamic mechanical properties of polyvinyl chloride(PVC)/thermoplastic polyurethane(TPU)blended alloy and the effect of microstructure on the mechanical properties of the blend system,quasi-static and dynamic mechanical properties experiments were conducted on PVC/TPU alloy specimens using a universal material testing machine and a split Hopkinson pressure bar(SHPB)experimental setup.The stress-strain curves in the wide strain rate range(0.001—5800 s^(-1))were obtained,and the structure and properties of PVC/TPU alloy were characterized by FTIR and SEM.The results indicate that the material exhibits significant strain rate strengthening effects under quasi-static tension and dynamic compression.The blending ratio affects its microstructure and mechanical properties.When the blending ratio is 90/10(PVC/TPU),the material has the highest elastic modulus,peak stress,and elongation at break,and the compatibility between the two phases is the best.As the proportion of TPU increases,the tensile and compressive mechanical properties of the material decrease,and a clear interface layer appears between the two phases.In addition,when the blending ratio is 50/50,the phase structure of the material is relatively complex,resulting in a complex morphology where the bicontinuous phase coexists with the‘sea island’structure.