Redução da massa molecular e funcionalização do poli(3-hidroxibutirato-co-3-hidroxivalerato) (PHBHV) via hidrólise ácida e transesterificação com glicóis

Abstract

Resumo: Neste trabalho foi realizado um estudo da redução da massa molecular do poli (3-hidroxibutirato-co-3-hidroxivalerato) (PHBHV) usando duas metodologias: hidrólise ácida com ácido clorídrico e transesterificação com etilenoglicol e hexilenoglicol. Foram investigados os parâmetros do processo: tempo, temperatura e concentração de catalisadores. Todas as metodologias estudadas geraram biopolímeros com massa molecular reduzida e funcionalizados com grupos hidroxila e carboxila terminais. Foram comparadas as metodologias estudadas, onde foi possível determinar a metodologia mais eficaz na funcionalização do PHBHV. A redução da massa molecular, associada a estratégias de funcionalização, é extremamente útil para promover alterações na taxa de degradação do PHBHV, ampliando assim as suas aplicações como biomateriais. Palavras-chave: PHBHV, redução da massa molecular, funcionalização, hidrólise ácida, transesterificação. Reduction of Molecular Weight and Functionalization of Poly(3-Hydroxybutyrate-co-3-Hidroxyvalerate) (PHBHV) by Acid Hydrolysis and Transesterification with GlycolsAbstract: In this work we investigated the reduction in molecular weight of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) with two methods: by acid hydrolysis and transesterification with ethylene and hexyleneglycol. The processing parameters studied were time, temperature and concentration of catalysts. Both methodologies resulted in functionalized biopolymers with hydroxyl and carboxyl end-groups and reduced molecular weight. A comparison of the methodologies allowed us to determine which one was more efficient for the functionalization of PHBHV. The reduction in molecular weight associated with functionalization strategies is extremely useful to induce changes in the degradation rate of materials, thus broadening their applications as biomaterials.

Application of 2K Experimental Design and Response Surface Methodology in the Optimization of the Molar Mass Reduction of Poly (3-Hydroxybutyrate-co-3-Hydroxyvalerate) (PHBHV)

“…PHB and PHBHV molar mass reductions can be obtained by thermal degradation [34,41], acid hydrolysis [4,[42][43], transesterification with glycols [44] reduction with NaBH 4 [6,45] or also in vivo esterification with PEG [46].…”

“…The studies indicated that the use of low molar mass PHBHV was more favorable in increasing entrapment and entrapment efficiency and enzyme activity [46]. Montoro, SR. et al [42] used the methods of acid hydrolysis and trans-esterification with ethylene and hexyleneglycol and also by reductions with sodium borohydride [4,6] to obtain PHBHV with molar mass reduced in order to develop materials suitable to be used as carriers in active systems. Liu,Q.…”