Melt polycondensation of L-lactic acid with Sn(II) catalysts activated by various proton acids: A direct manufacturing route to high molecular weight Poly(L-lactic acid)
✍ Scribed by Sung Il Moon; Chan Woo Lee; Masatoshi Miyamoto; Yoshiharu Kimura
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 156 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
Poly(L-lactic acid) (PLLA) was produced by the melt polycondensation of L-lactic acid. For the optimization of the reaction conditions, various catalyst systems were examined at different temperature and reaction times. It was discovered that Sn(II) catalysts activated by various proton acids can produce high molecular weight PLLA [weight-average molecular weight (M w ) Ն 100,000] in a relatively short reaction time (Յ15 h) compared with simple Sn(II)-based catalysts (SnO, SnCl 2 ⅐ 2H 2 O), which produce PLLA with an M w of less than 30,000 after 20 h. The new catalyst system is also superior to the conventional systems in regard to racemization and discoloration of the resultant polymer.