A comparative study of polyvinylidene fluoride and polypropylene hernia meshes in creep behavior and elasticity

Polypropylene (PP) is widely used in hernia repair for its compatibility with most mesh constructions. Polyvinylidene fluoride (PVDF) is a non-absorbable fluoropolymer with improved biostability, lower bending stiffness and less tissue reaction. Creep behavior and elasticity are significant properties of hernia mesh that influence the surgical handling of mesh and the postoperative recurrence. This work compares PVDF monofilament and hernia mesh with PP in creep deformation and elastic recovery percentage. The experimental results indicate that PVDF monofilament and mesh exhibit larger elastic recovery percentage, higher initial elongation and less creep deformation than PP mesh. The creep deformation of PVDF mesh in wale and course directions are 3.19 mm and 5.38 mm, which for PP mesh in wale and course directions are 7.73 mm and 8.30 mm. PVDF mesh has better performance in shape stability and elasticity. Additionally, creep models are used to analyze the experimental data and predict the long-term creep deformation. This method greatly reduces the time of creep experiment. In contrast to the four-element model and the Eyring's model, the modified generalized Maxwell model is more suitable to describe the creep curves of hernia meshes. Better agreements between theoretical and measured creep curves are observed. The predicted results demonstrate that PVDF mesh has better long-term shape stability than PP mesh.