Premium
Synthesis of a Novel Chitin Derivative Having Oligo( ε ‐caprolactone) Side Chains in Aqueous Reaction Media
Author(s) -
Detchprohm Sirinat,
Aoi Keigo,
Okada Masahiko
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20011201)202:18<3560::aid-macp3560>3.0.co;2-6
Subject(s) - chitin , polymer chemistry , monomer , aqueous solution , chemistry , copolymer , polymerization , crystallinity , side chain , caprolactone , carbon 13 nmr , polymer , chitosan , organic chemistry , crystallography
A chitin‐based graft copolymer, chitin‐ graft ‐oligo( ε ‐caprolactone) ( 2 ), was synthesized via ring‐opening graft polymerization of ( ε ‐caprolactone ( ε ‐CL) to ca. 50% partially deacetylated chitin 1 catalyzed by tin(II) 2‐ethylhexanoate in the presence of water as a swelling agent. The graft copolymer with ca. 40 wt.‐% poly( ε ‐CL) content was obtained by the reaction using the catalyst of 0.17 mol‐% and water of 130 mol‐%, respectively, to the ε ‐CL monomer at 100°C for 20 h. The chemical structure of 2 was characterized by IR, 1 H and 13 C NMR spectroscopies. The poly( ε ‐CL) contents by IR were in accordance with those determined by 1 H NMR analysis. T 1 measurements of an aqueous solution of 2 suggested that the molecular motion of the hydrophobic poly( ε ‐CL) side chains is restricted to some extent. On the other hand, it was demonstrated by 13 C CP/MAS NMR that the mobility of the chitin skeleton of 2 in the solid‐state is higher than that of the partially deacetylated chitin. X‐ray diffraction diagrams showed that 2 is amorphous, indicating that the crystallinity due to the chitin main chain was reduced by introducing the oligo( ε ‐CL) side chains.