Preparation Of Waterborne Polyurethane/carbon-based Composite Material By In-situ Polymerization

Polyurethane(PU)materials have attracted wide attention of researchers due to their unique structure and excellent performance,and have been applied to many fields(such as coatings,adhesives,etc.);Waterborne polyurethane(WPU)using water instead of organic solvents as dispersion media is one kind of new polyurethanes,whose property is friendly to the environment.However,WPU has some disadvantages poor heat resistance and water resistance,which inhibit its broad application and need to be improved.Applying nanoparticle additives is one of the effective ways to improve the properties of WPU.At present,there are many reports that many different types of nanoparticles have been introduced,but however,there is not enough systematic research on the compound modification of carbon system materials.Based on the above reasons,using carbon black(CB),amino multi-walled carbon nanotubes(NH2-MCNTS)and graphene oxide(GO)as modifiers,isophorone diisocyanate(IPDI)and poly propylene glycol 2000(PPG2000)as raw materials,dibutyltin dilaurate(T-12)as catalyst,three kinds of waterborne polyurethane(WPU)composites were prepared by in situ polymerization in this thesis:WPU/CB composites,WPU/CB/NH2-MCNTS nanocomposites and WPU/CB/GO nanocomposites.Meanwhile the structure and properties of three kinds of waterborme polyurethane composites were studied,and the following main results were obtained.The WPU/CB composites were prepared by in-situ polymerization.The introduction of filler particles has greatly improved the thermal and anticorrosive properties of the composites.FT-IR characterized the structure of prepared nanocomposites;SEM and TEM characterization revealed that the CB particles with the content of lwt%could be uniformly dispersed in the polymer matrix;Thermal analysis demonstrated that the thermal decomposition temperature(Td)of the prepared composites increased from 260.7? to 275.3?,Tg increased from 49.9? to 59.9?;EIS tests showed that the addition of carbon black particles could contribute to the corrosion resistance of the coating and was preferred when adding 1.0wt%CB(?=91.56%).A novel WPU nanocomposite modified by composite fillers consists of NH2-MCNTS and CB has been successfully prepared by in-situ polymerization.FT-IR characterized the structure of prepared nanocomposites.Thermal properties showed that the thermal stability of nanocomposites and glass transition temperature of hard segments(Tg-H)were raised by about 24?(from 260.7? to 284.7?)and 35?(from 49.9? to 85.8?)respectively,which was probably due to the uniformly dispersed filler particles,increased crosslink density of composites and the strong interfacial interactions between the fillers and WPU matrix evidenced by SEM and TEM microphotographs.Furthermore,EIS results indicated that the fillers greatly enhanced the resistance to corrosion with the maximum inhibition efficiency up to 99.46%.A novel WPU nanocomposite modified by composite fillers consists of GO and CB has also been successfully prepared by in-situ polymerization.FT-IR characterized the structure of prepared nanocomposites.Thermal properties showed that the thermal stability of nanocomposites and glass transition temperature of hard segments(Tg-H)were raised by about 23?(from 260.7? to 283.3?)and 45?(from 49.9? to 95.6?)respectively after adding 1.0wt%CB and 1.5mL GO,which was probably due to the uniformly dispersed filler particles,increased crosslink density of composites and the strong interfacial interactions between the fillers and WPU matrix evidenced by SEM and TEM microphotographs.Furthermore,EIS results indicated that the fillers greatly enhanced the resistance to corrosion,and the maximum inhibition efficiency upped to 97.44%when adding 1.0wt%CB and 1.0mLGO.To sum up,the properties of three kinds of waterborne polyurethane composites have been greatly improved,among which the heat resistance and corrosion resistance of the materials after adding NH2-MCNTS and go have been greatly improved.