Study On Synthesis And Properties Of Modified Waterborne Polyurethane

Waterborne polyurethane(WPU)due to its low temperature flexibility,no volatile organic compounds(VOC)or less VOC,water resistance,pH stability,excellent solvent resistance,excellent weather resistance and ideal chemical properties and mechanical properties,have been widely used in the coatings,leather,cosmetic and other industries.However,due to the hydrophilic group in the WPU molecular chain structure,the mechanical properties and water resistance of the coating film are poor.So it is the key to the development of the water-based polyurethane to improve its comprehensive performance.In this research,based on the waterborne polyurethane(WPU)formula,the functionalized polyurethane composites were synthesized by adding modifier.The obtained composite material has both excellent properties of the traditional waterborne polyurethane and the special properties of the modifier.In this paper,the effects of three kinds of modifiers on the performance of waterborne polyurethane were investigated.The structure proportion of soft and hard segment of polyurethane was changed by modifier.The active functional groups of modifier were introduced to improve the thermal compatibility of soft and hard segment of polyurethane.At same time,the modifier improved the performance of waterborne polyurethanes.The first type of modifier is diol modified nano silica particles.Because of the incompatibility between inorganic particles and polymers,inorganic nanoparticles are difficult to react directly with polymers.The diol is grafted onto nano silica by toluene diisocyanate,increasing its surface activity.The results were confirmed by IR and TG.The effects of adding amount on the performance of waterborne polyurethane films were investigated.The mechanical properties,water resistance and solvent resistance of the films were measured.The results showed that the mechanical properties,water resistance and solvent resistance of the polyurethane film were improved.The second type of modifier is modified graphene oxide.In this study,the modification of graphene oxide was introduced into the polyurethane molecular chain by chemical modification.The mechanical properties,thermostability of the films were measured.The results showed that the mechanical properties,thermostability of the polyurethane film were improved.At the same time,it is expected that the material has the function of anti electromagnetic radiation by using the high dielectric constant and the outer electron polarization relaxation.The third type of modifier is D-glucosamine hydrochloride.In this study,D-glucosamine hydrochloride was introduced into the polyurethane molecular chain by chemical modification.The effects of D-glucosamine hydrochloride as modifier on the antibacterial properties of polyurethane films were also investigated.Studies have shown that a small amount of D-glucosamine hydrochloride can significantly improve the antimicrobial properties of polyurethane films.The modifier can not only improve the mechanical properties of waterborne polyurethane,but also introduce the special properties of the modifier in the waterborne polyurethane,and the synthesized composite material has potential application value.