Viscoelastic behavior of core-shell structured nanofibers of PLA and PVA produced by coaxial electrospinning

• Published in: Polymer testing 2018-05, Vol.67, p.136-143
• Main Authors: Alharbi, Hamad F., Luqman, Monis, Fouad, H., Khalil, Khalil Abdelrazek, Alharthi, Nabeel H.
• Format: Article
• Language: English
• Subjects: Biocompatibility; Biological properties; Coaxial electrospinning; Core-shell structure; Creep strength; Ductility tests; Electrospinning; Fibers; Loss modulus; Mats; Mechanical properties; Nanofibers; Poly lactic acid; Poly vinyl alcohol; Polylactic acid; Polyvinyl alcohol; Spinning; Viscoelastic behaviour; Viscoelasticity
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2018.02.026

In recent work, we demonstrated the successful fabrication of core-shell nanofiber composites with enhanced tensile, surface wetting and cytocompatibility properties via coaxial electrospinning using PLA and PVA. It has been shown that core/shell-structured PLA/PVA nanofiber mat has the hydrophilic benefits of PVA and the attractive biological properties of PLA. In this paper, we present detailed mechanical evaluation of the electrospun coaxial nanofiber mats under static, dynamic and creep loading. The core/shell-PLA/PVA nanofibers showed nearly 233% and 150% increase in tensile strength and ductility, respectively, compared to pristine PLA. Dynamic loading tests were employed to study the viscoelasticity of the coaxial core-shell composite nanofibers at various temperatures and frequencies. The results of the storage and loss moduli of the coaxial nanofibers suggested strong physical interaction between the PLA and PVA layers, that contribute to the observed good mechanical behaviour. The better creep resistance of the coaxial PLA/PVA nanofibers under axial loading compared to the pristine materials provides further evidence for the physical interaction between the two constituent materials. A simple linear viscoelastic model is used to quantify the evolution of creep strain in pristine and coaxial materials. This research may help to understand the physical relation between the observed viscoelastic behaviour and the internal structure of coaxial core/shell nanofibers of PLA and PVA. •Coaxial electrospinning of composite core-shell nanofibers made of PLA and PVA.•Detailed mechanical response of the electrospun coaxial nanofiber mats under static, dynamic, and creep loading.•Strong physical interaction between the PLA and PVA layers affect the mechanical response of core-shell PLA/PVA structure.•Coaxial PLA/PVA mats show better creep resistance compared to pristine PLA and PVA.