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Information Journal Paper

Title

DIRECT CONDENSATION OF D,L- AND L-LACTIC ACIDS: EFFECT OF ALCL3 CATALYST ON MICROSTRUCTURAL ARRANGEMENTS OF HOMOPOLYMERS AND COPOLYMERS

Pages

  523-533

Abstract

 The effect of AlCl3 as a catalyst in direct condensation of homopolymerization and copolymerization of (rac and l) -lactic acid was studied. The morphological effect of dimer formation via racemization during polymerization with respect to time and catalyst concentration was investigated at 180oC under vacuum conditions (176 mmHg). The sequence distribution of triads and hexads was analyzed using 13C NMR spectroscopy. A combination of Avrami and Ozawa equations for mathematical modelling of the non-isothermal CRYSTALLIZATION kinetics of the synthesized poly (d, l -lactic acid) produced consistent results with the experimental data under these conditions. It is shown that AlCl3 promotes racemization which leads to formation of ill-defined polymers, as demonstrated by determinations of molecular weight distribution (Mn<5279 g/mol, PDI=1.4-3), optical purity (91.67% - 99.36%) and melting temperature (143-155oC). The ACTIVATION ENERGY for crystal growth during the cooling of molten samples of poly (d, l -lactic acid), as determined by Kissinger method, is found to be 45 kcal per mol. In this respect, the microstructural effect of copolymers on their thermal behaviour is discussed.

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  • Cite

    APA: Copy

    NAGARAJAN, SELVARAJ, TSIBOUKLIS, JOHN, & REDDY BOREDDY SIVA, RAMI. (2011). DIRECT CONDENSATION OF D,L- AND L-LACTIC ACIDS: EFFECT OF ALCL3 CATALYST ON MICROSTRUCTURAL ARRANGEMENTS OF HOMOPOLYMERS AND COPOLYMERS. IRANIAN POLYMER JOURNAL (ENGLISH), 20(6 (132)), 523-533. SID. https://sid.ir/paper/563520/en

    Vancouver: Copy

    NAGARAJAN SELVARAJ, TSIBOUKLIS JOHN, REDDY BOREDDY SIVA RAMI. DIRECT CONDENSATION OF D,L- AND L-LACTIC ACIDS: EFFECT OF ALCL3 CATALYST ON MICROSTRUCTURAL ARRANGEMENTS OF HOMOPOLYMERS AND COPOLYMERS. IRANIAN POLYMER JOURNAL (ENGLISH)[Internet]. 2011;20(6 (132)):523-533. Available from: https://sid.ir/paper/563520/en

    IEEE: Copy

    SELVARAJ NAGARAJAN, JOHN TSIBOUKLIS, and RAMI REDDY BOREDDY SIVA, “DIRECT CONDENSATION OF D,L- AND L-LACTIC ACIDS: EFFECT OF ALCL3 CATALYST ON MICROSTRUCTURAL ARRANGEMENTS OF HOMOPOLYMERS AND COPOLYMERS,” IRANIAN POLYMER JOURNAL (ENGLISH), vol. 20, no. 6 (132), pp. 523–533, 2011, [Online]. Available: https://sid.ir/paper/563520/en

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