Processing of (Co)Poly(2-oxazoline)s by Electrospinning and Extrusion from Melt and the Postprocessing Properties of the (Co)Polymers.

Wojciech Wałach,Ewa Kijeńska-Gawrońska,Marcelina Bochenek,Andrzej Dworak,Żaneta Górecka,Natalia Oleszko-Torbus,Wojciech Święszkowski,Alicja Utrata-Wesołek

doi:10.3390/polym12020295

Abstract

Poly(2-oxazoline) (POx) matrices in the form of non-woven fibrous mats and three-dimensional moulds were obtained by electrospinning and fused deposition modelling (FDM), respectively. To obtain these materials, poly(2-isopropyl-2-oxazoline) (PiPrOx) and gradient copolymers of 2-isopropyl- with 2-n-propyl-2-oxazoline (P(iPrOx-nPrOx)), with relatively low molar masses and low dispersity values, were processed. The conditions for the electrospinning of POx were optimised for both water and the organic solvent. Also, the FDM conditions for the fabrication of POx multi-layer moulds of cylindrical or cubical shape were optimised. The properties of the POx after electrospinning and extrusion from melt were determined. The molar mass of all (co)poly(2-oxazoline)s did not change after electrospinning. Also, FDM did not influence the molar masses of the (co)polymers; however, the long processing of the material caused degradation and an increase in molar mass dispersity. The thermal properties changed significantly after processing of POx what was monitored by increase in enthalpy of exo- and endothermic peaks in differential scanning calorimetry (DSC) curve. The influence of the processing conditions on the structure and properties of the final material were evaluated having in a mind their potential application as scaffolds.

Highlights

A great number of studies have focused lately on the processing of polymers into two- and three-dimensional matrices with strictly defined size and shape
Its cloud point temperature (TCP ) in aqueous solution is close to that of the human body, making it attractive for many applications, the presence of a crystalline phase is often not desirable in some systems. It was shown [48] that copolymerisation of iPrOx with n-propyl-2-oxazoline in an amount of 50 mol% significantly decreased the ability of the copolymers to crystallise, compared to the homopolymers of iPrOx
Poly(2-isopropyl-2-oxazoline)s and copolymers of 2-isopropyl-2-oxazoline with 2-n-propyl-2oxazoline were obtained via cationic ring-opening polymerisation initiated by methyl

Summary

Introduction

A great number of studies have focused lately on the processing of polymers into two- and three-dimensional matrices with strictly defined size and shape. Such matrices are of great interest in materials science because of their multiple applications in different fields, like electronic [1], or controlled drug delivery [2]. A great interest in recent years is the processing of polymers into materials that can be applied as scaffolds in tissue regeneration [3,4,5,6,7,8]. A simple and convenient technique that provides matrices in the form of two-dimensional non-woven fibrous mats is electrospinning of polymer solutions. The non-woven fibrous mat is composed of fibres with very small diameters, typically in the range of few a nanometres to micrometres, Polymers 2020, 12, 295; doi:10.3390/polym12020295 www.mdpi.com/journal/polymers

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