Design And Properties Of Waterborne Polyurethane Modified By Polydimethylsiloxane

Waterborne polyurethane,as an eco-friendly product,has attracted extensive concerns due to increasing awareness of environmental protection.Waterborne polyurethane has excellent mechanical properties,elasticity,durability,etc.,and is widely used in plastics,textiles and adhesives.Due to the introduction of hydrophilic groups,there is a certain gap of water resistance between waterborne polyurethanes and solventborne polyurethanes.Silicone has excellent chemical stability due to the unique chemical structure of the Si-O-Si chain,such as high temperature resistance,low temperature resistance,electrical insulation,water resistance and moisture resistance.Silicone and polyurethane can be combined to achieve complementary advantages.The main research contents of this article are as follows:Waterborne polyurethane was prepared by prepolymer self-emulsification method,using polytetrahydrofuran ether glycol(PTMG),isophorone diisocyanate(IPDI),polydimethylsiloxane(PDMS),isopropyl propyl triethoxysilane(IPTS)as the main raw material.Then the waterborne polyurethane with crosslinkable triethoxysilane groups in terminal groups(WPUT)was crosslinked by sol-gel method with PDMS as crosslinking agent.The effect of the amount of cross-linking agent on the particle size,micro-morphology,water resistance,and mechanical properties of the WPU was investigated.The results show that the XPS results confirm that the addition of crosslinking agent limits the migration of silicon.When the amount of crosslinking agent added is 10 wt%,the comprehensive performance of WPUT is the best,at this time the water absorption rate is 9.82%,The contact angle is 103.4°,the elongation at break is568.19%,and the tensile strength reaches 25.97 Mpa.Waterborne polyurethane was prepared by prepolymer self-emulsification method,using polytetrahydrofuran ether glycol(PTMG),isophorone diisocyanate(IPDI),polydimethylsiloxane(PDMS),isopropyl propyl triethoxysilane(IPTS)as the main raw material.Then the waterborne polyurethane with crosslinkable triethoxysilane groups in side groups(WPUS)was crosslinked by sol-gel method with PDMS as crosslinking agent.The effect of the amount of cross-linking agent on the particle size,micro-morphology,water resistance,and mechanical properties of the WPU was investigated.The results show that the XPS results confirm that the addition of crosslinking agent limits the migration of silicon.The contact angle and water absorption of WPUS decrease with the increase of the content of crosslinking agent.When no cross-linking agent is added,the water absorption of WPUS is 10.85%,the contact angle is 101.1°,and the surface energy is 32.40 mJ/m~2.When the amount of crosslinking agent is 5 wt%,WPUS has the best mechanical properties,with an elongation at break of 362%and a tensile strength of 18.9 MPa.2-amino-1,3-propanediol(APD)was introduced into the polyurethane system as a cross-linking agent to synthesize internal cross-linking silicone polyurethane.The internal cross-linking silicone polyurethane emulsion and its film were characterized by FT-IR,SEM,and other analytical methods.The water resistance,mechanical properties,and emulsion particle size of the internal cross-linking agent content of the emulsion and the film were investigated.The results show that when the APD content is 0.75 wt%,the WPU film has the best water resistance,the contact angle is 97.8°,and the water absorption rate is 4.26%,indicating that the increase of APD increases the crosslink density between the polyurethane segments,the water resistance is obviously enhanced.When the APD content is 0.5 wt%,the mechanical properties of the film are the strongest,the elongation at break is 560.47%,and the tensile strength reaches 47.59 Mpa.