Study On Wear-resistant And Yellowing-resistant Polyurethane

A series of solvent style polyurethane(PU)resins were prepared by prepolymer process.The effect of polyurethane steucture on the physical properties of polythane resins were studied.The work included two parts,(1)A series of yellow-resistant polyurethane resins for leathers were prepared and studied.The effect of soft segments,the ratio of chain extenders and the content of hard segment on the structure and properties of polyurethane resins were measured and compared.(2)The polyurethane ZnO peroxide nanocomposites with excellent abrasion resistance were synthesized and characterized.Four kinds of PU with different soft segments were prepared with PCDL,PCL,PBA,and PTMG as polyol respectively.The results showed that the polyurethane based on polyester had better mechanical properties than the polyurethane based on polyether.The stress at 100%and 300%strain and tensile strength of PU prepared with PCDL was the best,meanwhile the wear-resisitance was the best.The stress at 100%and 300%strain and tensile strength and the wear-resisitance of PU resins increased with the increase of hard segment content in the PU.The degree of hydrogen bonding of the PU films increased with the increase of hard segment,the degree of separation between soft and hard segments in the PU also increased.Meanwhile the yellowing resistance and anti UV aging properties increased.The stress at 100%and 300%strain and tensile strength and the wear-resisitance of PU increased with the increase of IPDA content in the PU.The degree of hydrogen bonding of the PU films decreased with the increase of hard segment,however,the degree of separation between soft and hard segments in the PU increased.The yellowing resistance and anti UV aging properties of PU increased.Finally,the polyurethane ZnO nanocomposites were synthesized by in situ methods.The results showed that when the ZnO nano-particles were introduced into the PU,the abrasion resistances,tensile strength,elongation at break and rigidity of polyurethane enhanced appreciably.