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Structure and properties of semiinterpenetrating polymer networks based on polyurethane and nitrochitosan
Author(s) -
Liu Haiqing,
Zhang Lina
Publication year - 2001
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/app.2167
Subject(s) - prepolymer , polyurethane , materials science , polymer chemistry , curing (chemistry) , ultimate tensile strength , castor oil , polymer , chemical engineering , composite material , chemistry , organic chemistry , engineering
Two semiinterpenetrating polymer networks (semi‐IPNs) based on trihydroxyl methylpropane–polyurethane (T‐PU) or castor oil–polyurethane (C‐PU) were prepared by curing the mixed solution of the polyurethane prepolymer and nitrochitosan (NCH). During the curing process, crosslinking and grafting reaction between the molecules of the PU prepolymer and NCH occurred, because of the high reactivity of remaining hydroxyl groups in the NCH with NCO groups of PU. The structure of the original semi‐IPN sheets and the sheets treated with acetone were studied by infrared, 13 C‐NMR, scanning electron microscopy, and dynamic mechanical analysis, showing interpenetration of NCH molecules into the PU networks. When nitrochitosan content (C NCH ) was lower than 10 wt %, the semi‐IPN sheets T‐PU and C‐PU had higher density and tensile strength (σ b ) than the systems with C NCH more than 20%. The trihydroxymethyl propane‐based PU reacted more readily with nitrochitosan to form the semi‐IPNs than castor oil‐based PU. The semi‐IPN coatings T‐PU and C‐PU were used to coat cellophane, resulting in intimate interfacial bonding. The mechanical strength and water resistivity of the cellophane coated with T‐PU coating were improved remarkably. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3109–3117, 2001