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Effect of prepolymer structure on the electro‐optic performance of polymer dispersed liquid crystals
Author(s) -
Kim Seon Hee,
Heo Chong Phil,
Park Kwan Sun,
Kim Byung Kyu
Publication year - 1998
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199806)46:2<143::aid-pi979>3.0.co;2-z
Subject(s) - prepolymer , adipate , polypropylene glycol , polycaprolactone , polyurethane , materials science , polyol , diol , glass transition , polymer , polymer chemistry , hexamethylene diisocyanate , composite material , chemical engineering , polyethylene glycol , engineering
The effect of prepolymer structure on the electro‐optic properties of polymer dispersed liquid crystals (PDLCs) prepared from UV‐cured polyurethane acrylates (PUAs) has been studied. Among four types of films with different soft‐segment structure, polypropylene glycol (PPG)‐ and polytetramethyl ether glycol (PTMG)‐based PUAs gave lower threshold ( V 10 ) and operating ( V 90 ) voltages, whereas polycaprolactone diol (PCL)‐based PUAs gave higher V 10 and V 90 voltages. The use of mixed polyol polypropylene glycol/ poly(tetramethylene adipate)diol) (PPG/PTAd) gave an electro‐optic response intermediate between the two. Regarding the effect of hard segment type, that from a linear aliphatic diisocyanate (hexamethylene diisocyanate, HDI) gave the lowest V 10 and V 90 voltages as well as transparent–translucent transition temperature compared with those from cycloaliphatic diisocyanates. This was interpreted in terms of a more flexible nature and hence a lower glass transition temperature of HDI‐based PUA. © 1998 SCI.