Thermal properties of polyurethane-based composites modified with chitosan for biomedical applications

Monika Szlachta,Katarzyna Nowicka,Kinga Pielichowska,Klaudia Ordon

doi:10.1007/s10973-020-09283-w

Monika Szlachta, Katarzyna Nowicka + Show 2 more

Open Access

https://doi.org/10.1007/s10973-020-09283-w

Copy DOI

Abstract

The thermal properties of chitosan and hydroxyapatite (HAp)-crosslinked polyurethanes (PU) prepared in a two-step bulk polymerization were investigated. Synthesis of PU was carried out using 1,6-hexamethylene diisocyanate, poly(ethylene glycol) 2000 and dibutyltin dilaurate as a catalyst. Various molar ratios of chitosan and 1,4-butanediol were applied, and the effects of incorporating different HAp amounts and the chitosan-to-BDO ratio were studied. It was found that the thermal properties of PU materials depend on polysaccharides and bioceramics load, which was confirmed by differential scanning calorimetry and thermogravimetry. The glass transition temperature increases with increasing chitosan fraction. Similarly, the onset temperature of degradation increased with chitosan addition. On the other hand, the presence of ceramics did not show a significant impact on the thermal properties of PU composites. Successful polymerization and chain extension of the isocyanate groups with hydroxyl moieties from chitosan and HAp were confirmed by Fourier transform infrared spectroscopy, and the morphology was examined using scanning electron microscopy.

Highlights

Polyurethane (PU) synthesis involves a step-growth polyaddition reaction between diisocyanate and polyol, where isocyanate group (–NCO) reacts with a hydroxyl group (–OH) and forms a urethane bond [1, 2]
We report on the synthesis and thermal properties of PU bone cement composed of hexamethylene diisocyanate (HDI) and poly(ethylene glycol) (PEG), crosslinked with chitosan and HAp
The FTIR study confirms the conversion of chitosan and HAp in reaction with the isocyanate group of the prepolymer

Summary

Introduction

Polyurethane (PU) synthesis involves a step-growth polyaddition reaction between diisocyanate and polyol, where isocyanate group (–NCO) reacts with a hydroxyl group (–OH) and forms a urethane bond [1, 2]. The incorporation of chitosan into the PU matrix as a chain extender is seen in the literature, especially as a component of the hard segment enhancing the material biocompatibility. The authors employed hydroxyl-terminated polybutadiene (HTPB) and 1,6-hexamethylene diisocyanate (HDI) and found that samples with lower contents of chitosan and higher contents of curcumin exhibited improved the thermal stability and tensile strength [11].

Results

Conclusion