High molecular weight methyl ester of microbial poly(β, l-malic acid): Synthesis and crystallization

• Published in: Polymer (Guilford) Vol. 47; no. 19; pp. 6501 - 6508
• Main Authors: Fernández, Carlos E., Mancera, Manuel, Holler, Eggehard, Galbis, Juan A., Muñoz-Guerra, Sebastián
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 07.09.2006; Elsevier
• Subjects: Applied sciences; Biotechnological polyester; Chemical modifications; Chemical reactions and properties; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Poly(malate); Poly(malic acid); Biotechnological polyester; Poly(malate); Poly(malic acid); Crystal form; Optically active polymer; Ester polymer; Experimental study; Functional polymer; Melt crystallization; Chemical modification; Microbial origin; Aliphatic polymer; Preparation; Non isothermal condition; Polyacid; Diazo compound; Kinetics; Methylation; Isothermal crystallization
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2006.07.063

High molecular weight poly(α-methyl β, l-malate) ( M n ∼ 25,000, PD ∼ 1.7) was prepared from microbial poly(β, l-malic acid) ( M n ∼ 29,000, PD ∼ 1.3) by methylation with diazomethane in dry acetone without substantial cleavage of the polyester main chain. The thermal properties of this poly(malate) were assessed and its crystal structure was preliminary examined. Two crystal forms were identified by X-ray diffraction, their occurrence being dependent on crystallization conditions. The kinetics of nonisothermal and isothermal crystallizations from the melt were studied and modelled using the Avrami approach. Results were compared to those recently reported by us for low molecular weight poly(α-methyl β, l-malate) ( M n ∼ 3000, PD ∼ 1.3).