Polyurethanes Based on Atactic Poly[(R,S)-3-hydroxybutyrate]: Preliminary Degradation Studies in Simulated Body Fluids

Joanna Brzeska,Aleksandra Heimowska,Marek Kowalczuk,Maria Rutkowska,Henryk Janeczek

doi:10.1007/s10924-014-0650-2

Abstract

The aliphatic polyurethanes based on atactic poly[(R,S)-3-hydroxybutyrate] (a-PHB) and commercial oligomerols: poly(e-caprolactone)diol and polyoxytetramethylenediol were investigated. a-PHB was obtained by anionic ring-opening polymerization of (R,S)-β-butyrolactone. The 4,4′-methylenedicyclohexyl diisocyanate and 1,4-butanediol were used as contributors of hard segments. The aim of the study was to determine the influence of synthetic, atactic a-PHB in soft segments of polyurethanes on their degradability in simulated body fluids (SBF) and Ringer solution. The incubation of polymer samples in both degradative solutions was carried out for 36 weeks. It was concluded that the presence of a-PHB in polyurethane structure accelerated their degradation in SBF and in Ringer solution and, protected the calcification process.

Highlights

Polyurethanes are commonly used in medicine as degradable and non-degradable implants [1, 2]
Application of aliphatic diisocyanate for hard segment creation prevents the risk of aromatic diamine formation as a by-product of the polyurethane degradation. We report in this current study on the influence of synthetic, atactic a-PHB used as a part of a soft segments (SSs) of aliphatic polyurethanes on their degradability in simulated body fluid (SBF) and in Ringer solution
The mass changes of polymer samples with a-PHB after incubation in simulated body fluids (SBF) indicated that polyurethanes with high content of hard segments were degraded faster than polyurethanes with lower molar ratio of NCO:OH in prepolymer (Fig. 1)

Summary

Introduction

Polyurethanes are commonly used in medicine as degradable and non-degradable implants [1, 2]. The biodegradability of polyurethanes can be accelerated by using appropriate substrates for their creation. Polyesterols such as poly(e-caprolactone)diol (PCL) and polyetheroles such as polyoxytetramethylenediol (PTMG) can be incorporated into soft segments (SSs) of polyurethanes. PCL is a biocompatible, biodegradable and semicrystalline aliphatic polyester, well known for possessing a valuable set of properties, such as nontoxicity for living organisms and resorption after an appropriate period of implantation time. It undergoes the enzymatic degradation and slow hydrolytical processes. Whereas PTMG oligoetherol, used as SSs of polyurethanes, degrades mainly by oxidizing mechanisms [4]

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Conclusion