A hydrogenated hydroxy-terminated butadiene–acrylonitrile copolymer-based polyurethane elastomer with improved mechanical properties and aging resistance

Abstract

A hydrogenated hydroxy-terminated butadiene–acrylonitrile copolymer (HHTBN)-based polyurethane elastomer (PUE) was prepared by using HHTBN as the soft segments in a casting method.

Tuning nanophase separation behavior in segmented polyhydroxyurethane via judicious choice of soft segment

“…In general, elongation-at-break and Young's modulus values of the PHUs in this study are similar to those obtained in conventional TPUs; however, the tensile strength values of the PHUs are inferior [66][67][68][69]. Further structure-property-relationship studies which consider the influences of hard-segment, chain-extender, and other soft-segment structures are warranted to obtain segmented PHUs with improved properties.…”

“…The soft segment plays a critical role in controlling the degree of nanophase separation in segmented PUs . Among many soft segments studied, polybutadiene-based soft segments have been reported to exhibit a very high degree of nanophase separation relative to those conferred by polyether-and polyester-based soft segments [66][67][68][69][70][71][72][73][74][75][76]. This result can be attributed to the non-polar nature of and the lack of hydrogen bond acceptor in polybutadiene-based soft segments, limiting hydrogen bonding to occur only within the hard segment.…”

Degradation and stabilization of polyurethane elastomers

“…As discussed already, hydrogenated PB is more resistant to oxidation due to the absence of double bonds [208,209]. While some of the C=C bonds of an HTPB-based PU were found to be oxidized to form carbonyl functional groups during ozone ageing at a concentration of 50 ppm for 48 h, its hydrogenated counterpart showed no obvious change under the same conditions [215]. Elimination of double bonds or crosslinking at the immediate surface could also improve ozone resistance of elastomers [408].…”

“…On the other hand, to the extent that labile or photosensitive groups can be replaced by less reactive groups (bonds with a higher BDE or non-chromophore groups), improved resistance to photodegradation will result [207]. [215]. Alternatively, PIB can also be used as a replacement macrodiol for PB for PU synthesis [46,[63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82].…”

“…For example, Sarkar and Adhikari [374] reported that with the same NCO/OH ratio, adding lignin to build a lignin-co-HTPB copolymer to react with TDI could lead to a PU with increased thermal resistance during isothermal ageing at 100 °C for 48 h. Alternatively, hydrogenation of PUs containing unsaturated C=C bonds in the macrodiol segments may give the polymer better resistance to heat and oxidation [215,401]. This strategy has been demonstrated to be successful for PUs based on PIP (at 150 °C in air for up to one month) [401] and PB (at 120 °C for up to 72 h) [215].…”