Methylenediphenyl diisocyanate (MDI) was used as the chain extender for low molecular weight poly(lactic acid) (PLA) to produce high molecular weight biodegradable polymer material with a better heat resistance. PLA prepolymer with a number-average molecular weight (M n ) of 5800 and a weight-averag
Polymerization of aqueous lactic acid to prepare high molecular weight poly(lactic acid) by chain-extending with hexamethylene diisocyanate
β Scribed by Seong Ihl Woo; Bong Oh Kim; Hae Sang Jun; Ho Nam Chang
- Publisher
- Springer
- Year
- 1995
- Tongue
- English
- Weight
- 309 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0170-0839
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π SIMILAR VOLUMES
H NMR spectra were run in deuterated chloroform, on a 60 MHz Varian 360 A spectrometer, using tetramethylsilane (TMS) as internal reference.
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 pr
A novel and e β ective chain-extension procedure for obtaining highmolecular-weight PLGA-based bioerodible polymers is described. This procedure consists in a polycondensation reaction between PLGA thermal oligomers of average molecular weight 1000Γ3000 and bischlorofomates of either simple diols or