Study On The Blending Of Biodegradable Polyester Poly(3-hydroxybutyrate) And Poly(Lactic Acid)

At present the study on the application of medical biodegradable polymers has been moreand more important. Two kinds of polyesters poly (3-hydroxybutyrate) (PHB) and poly (lacticacid) (PLA), with certain mechanical strength, elastic modulus, heat molding andbiocompatibility, has been paid more attention than other polymers.High degree of crystallinity and narrow processing window has greatly limited theapplication of poly (3-hydroxybutyrate), so it is necessary to blending other materials withPHB. In this study, it is the first time to blending dendrimers with linear PHB. Chloroform assolvent dissolved PHB and dendrimers and then volatilized at room temperature. It wasrevealed that there were mainly two types of interactions in the blending system: theplasticizing or lubricating effect of the low melting spherical dendrimers molecules improvedthe polymer chain mobility through the suppression of PHB crystallization in the blends; Thedendrimers also functioned as cross-linking agents or antiplasticizing agents via weakhydrogen bonding to enhance the overall intermolecular interactions which decrease the chainmobility and thus cause the increase of glass transition temperature (T_g) of PHB.Poly (lactic acid) has been unable to meet applications. High degree of crystallinity, poortoughness and other shortcomings has limited the application of PLA as tissue engineeringmaterials or thermal plastics. Further study was necessary to improvement PLA propeties. Inthis study, poly (3-hydroxybutyrate-co-4-hydroxybutyrate) [P (3HB-40%4HB)], as elastomer,was used to modify poly (lactic acid) (PLA). The results showed that 20% of the P(3HB-40%4HB) can significantly improve the toughness, elongation than pure PLA from 44%to 140%.