Effects of moisture on the glass transition temperature of polyurethane shape memory polymer filled with nano-carbon powder

One simple approach to produce electrically conductive polymers is to fill them with conductive powders. This paper investigates the effects of moisture on the glass transition temperature of a polyurethane shape memory polymer (SMP) filled with nano-carbon powders. it is found that the SNIP composites before immersion in water have a slightly lower glass transition temperature, and in the mean time, the moisture fraction at the saturation point upon immersion is also lower. On the other hand, the moisture can remarkably reduce the glass transition temperature of the composites. Heating to over 180 degrees C is an effective way to remove the moisture, which also results in the glass transition temperature back to the original. As the glass transition temperature can be greatly reduced by moisture, a novel feature, namely, the water actutable recovery of SMP composites is also proposed based oil this study. (c) 2004 Elsevier Ltd. All rights reserved.