Lipase-catalyzed synthesis and characterization of biodegradable polyester containing l-malic acid unit in solvent system

• Published in: Journal of applied polymer science 2011-04, Vol.120 (2), p.1114-1120
• Main Authors: Yao, Dahu, Li, Guangji, Kuila, Tapas, Li, Peng, Kim, Nam Hoon, Kim, Seong-Il, Lee, Joong Hee
• Format: Article
• Language: English
• Subjects: Applied sciences; biodegradable; enzymes; Exact sciences and technology; Materials science; Organic polymers; Physicochemistry of polymers; Polycondensation; polyesters; Polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 0021-8995; 1097-4628; 1097-4628
• DOI: 10.1002/app.33257

Lipase-catalyzed direct polycondensation of L-malic acid (L-MA), adipic acid, and 1,8-octanediol in organic media was achieved using Novozym 435 as the biocatalyst. ¹H-nuclear magnetic resonance spectroscopy indicated that the selectivity of Novozym 435 was unaffected by changes in the organic media. The molecular weight (Mw) of the copolymers was affected by the L-MA feed ratio in the diacids, hydrophobicity of the solvent, and solubility of the substrates in the solvents. The Mw reached a maximum of 17.4 kDa at 80°C in isooctane at a L-MA feed ratio in the diacids of 40 mol %. The Mw increased from 3.2 to 16.6 kDa when the reaction time was extended from 6 to 48 hr at 70°C, and remained relatively constant with further increases in reaction time from 48 to 72 hr. The hydrophilicity, thermal stability, and crystallizability of the copolymer were also investigated.