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End‐group effect on chain conformation of poly(propylene glycol) and poly(ethylene glycol)
Author(s) -
Yoon Sunghoe,
MacKnight William J.,
Hsu Shaw Ling
Publication year - 1997
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/(sici)1097-4628(19970404)64:1<197::aid-app18>3.0.co;2-1
Subject(s) - ethylene glycol , polymer chemistry , differential scanning calorimetry , end group , ether , glass transition , polyvinyl alcohol , polymer , peg ratio , pendant group , chemistry , hydrogen bond , materials science , molecule , organic chemistry , copolymer , thermodynamics , physics , finance , economics
A comparison is made of the chain conformational distribution of hydroxy‐terminated poly(propylene glycol) (PPG) and poly(ethylene glycol) (PEG) with their methoxy‐terminated derivatives. The significant end‐group dependence on the glass transition temperature in PPG was observed by differential scanning calorimetry. Raman active skeletal vibrations in the low‐frequency region indicated a significant difference in chain conformation distribution between methoxy‐ and hydroxy‐terminated PPGs, yet almost no difference between MPEG and HPEG. The increased chain stiffness in HPPG in comparison to MPPG has been attributed to the hydrogen‐bonding interaction associated with the hydroxy end group in HPPG. Furthermore, the structural differences observed between PPG and PEG have been attributed to the differences in the interaction of the hydroxy end group to the ether oxygen in the two polymers. The interaction between the hydroxy end group and ether oxygen differs because the —CH 3 side group is present for one and not for the other. These structural differences are reflected in the glass transitions temperatures measured. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 197–202, 1997