ABSTRACT The present work focuses on the determination of volume change accompanying deformation and Poisson's ratio for electrospun nanofibrous membranes. For this purpose, polyurethane (PU) is considered for the fabrication of electrospun nanofibrous membranes. Three different sample thicknesses are fabricated. Following this, surface morphology analysis and fibre orientation analysis are conducted to investigate the variation of properties between electrospun PU membranes of different thicknesses. Subsequently, PU specimens are subjected to uniaxial extension test where the changes in sample width and thickness are recorded as a function of applied strain. Volume changes are computed while further analysis on the relationship between transverse strains and axial strain provided the values of Poisson's ratio. For all three electrospun PU samples investigated, significant volume changes are observed while the in-plane Poisson's ratio is found to be around 0.55. However, the out-of-plane Poisson's ratio of electrospun PU membranes are not classical and remains undetermined.

中文翻译：

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泊松比和体积随随机取向电纺纳米纤维膜变形的变化

摘要目前的工作重点是确定电纺纳米纤维膜伴随变形和泊松比的体积变化。为此，聚氨酯 (PU) 被考虑用于制造电纺纳米纤维膜。制造了三种不同的样品厚度。在此之后，进行表面形态分析和纤维取向分析以研究不同厚度的电纺PU膜之间的性能变化。随后，对 PU 样品进行单轴拉伸试验，其中样品宽度和厚度的变化被记录为所施加应变的函数。计算体积变化，同时进一步分析横向应变和轴向应变之间的关系，提供泊松比的值。对于所研究的所有三个电纺 PU 样品，观察到显着的体积变化，同时发现面内泊松比约为 0.55。然而，电纺 PU 膜的平面外泊松比不是经典的，仍未确定。