Preparation And Properties Of Waterborne Polyurethane For Labor Protection Gloves

Waterborne polyurethane is a new type of polyurethane system with water as the dispersing medium.It has the advantages of environmental protection,excellent mechanical properties,good compatibility and easy modification.It is widely used in adhesives,coatings,leather and other fields.Waterborne polyurethane has gradually replaced solvent polyurethane,which has become an important direction of the development of polyurethane industry.However,the wear resistance and water resistance of waterborne polyurethane are far less than that of solvent polyurethane,which limits the application of waterborne polyurethane to a certain extent.Therefore,the modification and reinforcement of waterborne polyurethane are widely concerned by scholars at home and abroad.The waterborne polyurethane is mainly composed of isocyanate in hard segment,chain extender and polyol in soft segment.The micro phase separation structure is formed due to the thermal incompatibility of soft segment and hard segment.On the one hand,starting from the structure of water-based polyurethane,by adjusting the proportion of soft and hard segments of water-based polyurethane,selecting isocyanate,chain extender and macromolecular polyol with excellent performance,and adjusting the degree of micro phase separation,we can get the water-based polyurethane with desired performance;on the other hand,by adding nano fillers to modify the water-based polyurethane,we usually choose graphene and carbon nanotubes These nano fillers have obvious reinforcing effect on waterborne polyurethane,but their compatibility with waterborne polyurethane is poor,and they are easy to agglomerate,which weakens the performance of waterborne polyurethane.Recently,chitin nanocrystals with high crystallinity,high modulus of elasticity,biodegradability and easy to modify are widely concerned because of their abundant hydrophilic groups on the surface,It has good dispersion stability in aqueous solution,good compatibility with waterborne polyurethane, and good improvement on the performance of waterborne polyurethaneIn this paper,waterborne polyurethane emulsion was prepared by adjusting the soft and hard structure of waterborne polyurethane and adding chitin nanoparticles to waterborne polyurethane system.In this experiment,water-borne polyurethane was prepared by three different types of macromolecular polyols: PTHF,PNA and PCL.Through water resistance test,the best water-resistant PTHF was selected.Then the influence of different ratio of IPDI and MDI on the performance of water-borne polyurethane was investigated The results show that MDI with good symmetry can effectively improve the degree of microphase separation,promote the orderly arrangement of hard segments,and then introduce sulfonic polyol instead of part of DMBA into the aqueous polyurethane system,effectively improve the dispersion stability of the aqueous polyurethane,improve the elongation at break of the aqueous polyurethane,and finally remove the aqueous polyurethane It was found that chitin,which was oxidized by acetyl and tempo,not only enhanced the tensile strength of waterborne polyurethane,but also increased the elongation at break of waterborne polyurethane.