发泡聚乙烯醇缓冲机理研究

Cushion Mechanism of Expanded Polyvinyl Alcohol

通过对不同密度的发泡聚乙烯醇进行静态压缩试验以及用扫描电镜观察不同压缩阶段泡孔结构的变化,分析了发泡聚乙烯醇的力学性能及缓冲机理。结果表明:材料静态压缩应力-应变曲线呈现线弹性、塑性屈服及密实化3个阶段;发泡聚乙烯醇不同方向力学性能的差异表明了其结构各向异性;材料的弹性模量及屈服强度与其泡孔结构有关,均会随着密度的增加而增大,材料的能量吸收效率在应变为0.55左右的区域达到最大值,具有最佳的吸能效果。最后分析了发泡聚乙烯醇压缩变形机理,其主要以孔壁弯曲变形为主,孔径很大时孔隙中流动气体对其压缩性能的影响可忽略不计。为开发不同泡孔结构发泡聚乙烯醇材料应用于各种产品的缓冲包装设计提供参考。

Static compression test of expanded polyvinyl alcohol with different densities and SEM observation of foam structures of different compressive stage were carried out. Mechanical property and cushion mechanism of expanded polyvinyl alcohol were studied. The results showed that compressive stress-strain curve of material includes three sta- ges, which are linear elasticity, plastic yield and densification ; the difference of mechanical property in different com- pressive direction indicates structural anisotropy of the material ; elasticity modulus and yield strength of the material are affected by foam structure, which increase with increasing density; energy absorption efficiency of material can be maxi- mizing when strain is about O. 55 ; the final compressive deformation mechanism is mainly bending deformation of pore wall ; the influence of gas on compressive mechanical property can be ignored when pore size of material is very big. The purpose was to provide references cushion packaging design using expanded polyvinyl alcohol of different foam structure.