Preparation And Properities Of Polyurethane With Degradation And Hydrolyzation

In this thesis we focus on solving the problems on marine biofouling, especially on thoseoccurring in the static marine environment. A series of degradable polyurethanes had beensynthesized via a combination of thiol-ene click reactions, free radical polymerizations andstep-growth polymerizations.Polyurethane with poly(ε-caprolactone)(PCL) as the soft segments of the main chain andpoly(triisopropylsilyl acrylate)(PTIPSA) as the side chains by a combination of radicalpolymerization and a condensation reaction. Quartz crystal microbalance with dissipationstudies show that polyurethane can degrade in the presence of enzyme and the degradationrate decreases with the PTIPSA content. Our studies also demonstrate that polyurethane isable to hydrolyze in artificial seawater and the hydrolysis rate increases as the PTIPSAcontent increases. Marine field tests reveal that polyurethane has good antifouling abilitybecause polyurethane with a biodegradable PCL main chain and hydrolyzable PTIPSA sidechains can form a self-renewal surface. Polyurethane was also used to carry and release arelatively environmentally friendly antifoulant, and the combined system exhibits a muchhigher antifouling performance even in a static marine environment.Second, we have prepared different kinds of degradable polyurethane with hydrolyzablesilyl ester side chains by changing the length of the side chain and the segments such aspoly(ε-caprolactone), poly(ethylene adipate) or poly(L-lactide) in the main chain. The massloss and the water adsorption experiments indicate that the degradation rate increases as thesilyl side chain length and the content of ester groups in main chain. The releasing rate testrevealed that the release rate of DCOIT increases as the length of side chains increases andhas an optimal value in the content of ester groups in main chain. We also examined the timedependence of surface chemistry and structure by contact angle and surface roughnessmeasurements. The PUs surface have been hydrophilic after hydrolysis and the surfaceroughness slightly changes after immersing in the ASW. These results indicate that thehydrophilic surface is favorable to the reduction of frictional drag. Marine field tests revealedthat the combination of such a degradable polyurethane and environmentally friendlyantifoulants exhibits good antifouling ability.