Selective Depolymerization and Effects of Homolysis of Poly(L-lactic acid) in a Blend with Polypropylene

Blends of poly(L-lactic acid) (PLLA) and polypropylene (PP), which are candidates for the practical use of PLLA, were investigated for selective degradation of PLLA, resulting in quantitative conversion of PLLA components into cyclic monomers, lactides, using magnesium oxide (MgO) as a depolymerization catalyst. Obviously, the catalyst MgO selectively accelerated only the PLLA depolymerization in the blends, dominantly generating L,L-lactide as a volatile product and separating the PP component. Expected effects of homolysis in the blend system were also determined as slight changes in activation energy of degradation for both the components and through the suppression of degradation by an antioxidant

Poly(tetramethyl glycolide) from Renewable Carbon, a Racemization-Free and Controlled Depolymerizable Polyester

Racemization-free and depolymerization-controllable poly(tetramethyl glycolide) (PTMG) was synthesized from renewable resources: D/L-lactic acids and pyruvic acid. PTMG overcomes the undesirable properties of poly(lactic acid) such as low heat-resistance and racemization causing the decrease in crystallinity. PTMG was shown to have a higher melting point than 200 °C and to be a superior recyclable material capable of being depolymerized controllably into cyclic dimer tetramethyl glycolide (TMG) or methacrylic acid (MA) by using specific catalysts. PTMG can be reversibly synthesized from the depolymerized TMG. Moreover, biomass-based poly(methyl methacrylate) (PMMA) was prepared from the recovered MA

Selective Depolymerization and Effects of Homolysis of Poly(L-lactic acid) in a Blend with Polypropylene

Blends of poly(L-lactic acid) (PLLA) and polypropylene (PP), which are candidates for the practical use of PLLA, were investigated for selective degradation of PLLA, resulting in quantitative conversion of PLLA components into cyclic monomers, lactides, using magnesium oxide (MgO) as a depolymerization catalyst. Obviously, the catalyst MgO selectively accelerated only the PLLA depolymerization in the blends, dominantly generating L,L-lactide as a volatile product and separating the PP component. Expected effects of homolysis in the blend system were also determined as slight changes in activation energy of degradation for both the components and through the suppression of degradation by an antioxidant

Poly(tetramethyl glycolide) from Renewable Carbon, a Racemization-Free and Controlled Depolymerizable Polyester

Poly(tetramethyl glycolide) from Renewable Carbon, a Racemization-Free and Controlled Depolymerizable Polyeste