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Starch‐ g ‐polycaprolactone copolymerization using diisocyanate intermediates and thermal characteristics of the copolymers
Author(s) -
Kweon DongKeon,
Cha DongSoo,
Park HyunJin,
Lim SeungTaik
Publication year - 2000
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/1097-4628(20001031)78:5<986::aid-app70>3.0.co;2-t
Subject(s) - polycaprolactone , copolymer , hexamethylene diisocyanate , starch , polymer chemistry , glass transition , materials science , differential scanning calorimetry , polyurethane , chemistry , organic chemistry , polymer , composite material , physics , thermodynamics
Starch‐ g ‐polycaprolactone copolymers were prepared by two‐step reactions. The diisocyanate‐terminated polycaprolactone (NCO–PCL) was prepared by introducing NCO on both hydroxyl ends of PCL using diisocyanates (DI) at a molar ratio between PCL and DI of 2:3. Then, the NCO–PCL was grafted onto corn starch at a weight ratio between starch and NCO–PCL of 2:1. The chemical structure of NCO–PCL and the starch‐ g ‐PCL copolymers were confirmed by using FTIR and 13 C‐NMR spectrometers, and then the thermal characteristics of the copolymers were investigated by DSC and TGA. By introducing NCO to PCL ( M n : 1250), the melting temperature ( T m ) was reduced from 58 to 45°C. In addition, by grafting the NCO–PCL (35–38%) prepared with 2,4‐tolylene diisocyanate (TDI) or 4,4‐diphenylmethane diisocyanate (MDI) onto starch, the glass transition temperatures ( T g 's) of the copolymers were both 238°C. With hexamethylene diisocyanate (HDI), however, T g was found to be 195°C. The initial thermal degradation temperature of the starch‐ g ‐PCL copolymers were higher than that of unreacted starch (320 versus 290°C) when MDI was used, whereas the copolymers prepared with TDI or HDI underwent little change. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 986–993, 2000