Solid State Polymerization of Poly(L-Lactide): Multiple-Fold Increase in Molecular Weight via an Efficient Catalyst System
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Title |
Solid State Polymerization of Poly(L-Lactide): Multiple-Fold Increase in Molecular Weight via an Efficient Catalyst System
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Creator |
KATIYAR, V
NANAVATI, H |
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Subject |
MELT/SOLID POLYCONDENSATION
MELTING BEHAVIOR LACTIC-ACID CRYSTALLIZATION POLYLACTIDES POLYMERS |
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Description |
We report the synthesis of high molecular weight (MW), high crystallinity (X(c)) poly(L-lactic acid) (PLLA), with improved thermal stability, by solid state polymerization (SSP) of low MW PLLA prepolymer, pre-PLLA. SSP enabled pre-PLLA is synthesized by ring opening polymerization (ROP) of L-lactide using a ternary catalyst complex of L-lactide, stannous octoate, and L-lactic acid oligomer (OLLA). We demonstrate that this ROP, although a chain-growth reaction, yields pre-PLLA with end-groups, which enable step growth SSP. MW increases similar to 9 fold, with X(c) reaching beyond 90%, during the SSP process. Such high values of crystallinity could be due to the synchronization of the crystallization rate with that of the slower and longer lasting step-growth SSP. Nuclear magnetic resonance spectroscopy confirms that SSP is indeed a step-growth reaction. In comparison, Zn(OLLA)(2) only couples two pre-PLLA chains during SSP. In addition, the radial spherulite growth rate has been quantified with annealing time of SSP synthesized PLLA. POLYM. ENG. SCI., 51:2078-2084, 2011. (C) 2011 Society of Plastics Engineers
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Publisher |
WILEY-BLACKWELL
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Date |
2012-06-26T04:59:01Z
2012-06-26T04:59:01Z 2011 |
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Type |
Article
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Identifier |
POLYMER ENGINEERING AND SCIENCE,51(10)2078-2084
0032-3888 http://dx.doi.org/10.1002/pen.22133 http://dspace.library.iitb.ac.in/jspui/handle/100/13923 |
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Language |
English
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