Biodegradable polyester blends for biomedical application

Abstract

SYNOPSISA new family of bioabsorbable materials suitable for biomedical applications was designed and prepared by means of blending of some available polyesters to develop new biodegradable materials tailored for different requirements. Multiphase polymer blends containing poly(d, l-lactide) (PLA), poly(e-caprolactone) (PCL), poly(d, l-lactide-co-poly(ethy1ene glycol) (PELA), poly(c-capro1actone)-co-poly(ethy1ene glycol) (PECL), and poly(P-hydroxybutyrate) (PHB), PLA/PCL, PELA/PECL, PHB/PLA, PHB/PELA, PHB/PCL, and PHB/ PECL blends were respectively investigated. It was found that PLA/PCL, PHB, and PHB/ PLA and PHB/PCL blends were seemingly immiscible, with their morphology and hydrolytic behavior were determined by the composition of the blends. On the other hand, the miscibility of PELA/PECL, PHB/PELA, and PHB/PECL blends was improved by using PELA and/or PECL block copolymers that contained poly(ethy1ene glycol) (PEG) as compatibilizer. The blends showed to a certain extent miscibility, fine phase morphology, and fast hydrolysis. 0

Blending of Polyhydroxybutyrate-co-valerate with Polylactic Acid for Packaging Applications – Reflections on Miscibility and Effects on the Mechanical and Barrier Properties

“…Melting exotherms at low temperatures (~130 °C) are associated with imperfectly crystallised PLA, due to interlamellar crystallization with PHBV. 17,29,32,34,35,[41][42][43]45 For a tentative quantification of miscibility, the G-T-equation (Equation 6) was applied with the constant k as a fitting parameter with molecular significance, as defined by Schneider. 56,57 The calculat- for low molecular weight PLA blended in high molecular weight PHB (bacterial origin), and the data of Ohkoshi, Abe 35 for low molecular weight atactic PHB blended with high molecular weight PLA.…”

“…Due to the low intensity of this peaks, amounts of PLA may be trapped in the interlamellar regions of PHBV spherulites, as stated by several authors. 17,29,32,34,35,[41][42][43]45 For the higher molecular weight blends, two more pronounced post-crystallisation peaks emerge in the thermograms. These post-crystallisations may belong to phases enriched with PLA as mentioned above.…”

“…Hence, it can be assumed that the first melting transition belongs to crystallised phases made of interpenetrating spherulites or PHBV spherulites disturbed by included amorphous PLA or interlamellar post-crystallised PLA, as discussed by several authors. 17,29,32,34,35,[41][42][43]45 The higher melting point transition should therefore belong to a pure PHBV phase. Table 3).…”

Effect of the molecular weight on the crystallinity of PCL-b-PLLA di-block copolymers

“…Copolymers [13][14][15], blends [16] and composites [17] with PLLA and PCL have been developed in order to take advantage of the improved synergic properties offered by both polymers. Actually, for this integration strategy, copolymerization represents a better route in comparison with blending due to the immiscibility of the homopolymers [18]. Moreover, copolymers based on PLLA and PCL show shape memory properties [19][20][21].…”

Estudo do revestimento de modelos de stents coronários biorreabsorvíveis de PLLA com PLDLA/PLGA e ácido hialurônico

“…(Carvalho, 2002;Duek et al, 1999;Erbetta et al, 2011;Ignatius et al, 1996;Rezende et al, 2005;Santos et al, 2007;Yin et al, 2014;Zhang et al, 1995 (Dallan, 2005;Ratner et al, 1996).…”