POLY(HYDROXYBUTYRATE-CO-HYDROXYVALERATE) MICRONIZATION BY SOLUTION ENHANCED DISPERSION BY SUPERCRITICAL FLUIDS TECHNIQUE

G P S Aguiar,C D Magro,M Lanza,J V Oliveira

doi:10.1590/0104-6632.20180354s20170501

Abstract

ABSTRACT Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biodegradable polymer used for a wide range of applications, especially in biomedical and food industry, for which bioactive compound encapsulation is noteworthy. This work aimed to micronize PHBV by Solution Enhanced Dispersion by Supercritical Fluids technique and evaluate possible changes in polymer crystallinity. A 23 Central Composite Design with 3 central points was used to analyze the inﬂuence of pressure, temperature and PHBV concentration on particle size produced. Micronized particles were mostly spherical with sizes from 210 to 720 nm, and free of organic solvents. PHBV crystallinity degree was approximately 20% higher when polymer was processed at 8 MPa compared to that processed at 10 and 12 MPa, as well as to the raw polymer. Results suggest versatility in PHBV application according to SEDS process parameters and the possibility of its use in drug delivery systems.

Highlights

Polymers have been used for many applications in our society, in different industrial fields
A 23 Central Composite Design (CCD) with three central points was used to evaluate the influence of variables pressure, temperature and PHBV concentration on particle size obtained and all CCD data were analyzed with a confidence level of 95%
Quantification of residual solvent was investigated by gas chromatography - flame ionization detector (GC-FID) using the same operation conditions as in the GC-MS (Aguiar et al, 2016)

Summary

Introduction

Polymers have been used for many applications in our society, in different industrial fields. The use of biodegradable polymers has attracted attention from scientists and industry due to the structural similarity with synthetic polymers from non-renewable sources but lower environmental impact generated. Polyhydoxyalkanoates (PHAs) are noteworthy due to the versatility in the production of different copolymers. PHAs production is based on microbiological conversion of alcaligenes bacteria, which consume the carbon source from growth medium and transform it into polyesters stored as intracellular granules. The polyesters are obtained in the final form by downstream processes (extraction, separation and purification). Variations in the length and composition of the polymeric chain allow a wide potential of applications (Oliveira et al., 2006). Toxicity analyses have shown that monomers of PHAs may not be toxic to humans, but can even provide some therapeutical or nutritional benefits (Chen and Wu, 2005)

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Results