Synthesis And Application Of Hyperbranched Waterbased Polyurethane Based On Poly （Propylene Carbonate）

Hyperbranched waterborne polyurethane（HWPU）combines the structural qualities of hyperbranched polymers with the mechanical capabilities and water resistance of polyurethane,resulting in a material with a wide range of applications.As a result,the development of hyperbranched polyurethane with unique structures and multi functionality has increasingly become a research hotspot,particularly for waterbased resins with great performance and environmental protection.Our research group has been working on carbon dioxide copolymer polyol production and application（PCD）.Although the waterborne polyurethane synthesized from it has high strength and water resistance,no research report on HWPU exists.It is anticipated that PCD will be used as the primary raw material to synthesize PCD-HWPU with satisfactory performance.The following three sections comprise the major research content.（1）Using the coupled monomer method,PCD,IPDI and DMPA were used as raw materials to synthesize polyurethane prepolymer（A₂）,and DEOA（b B₂）to synthesize a series of HWPU.The same method is utilized to cure and modify HWPU using a water-dispersed HDI curing agent.On the basic properties of HWPU,the impacts of monomer concentration,R value,neutralization degree,hydrophilic monomer,and curing agent were extensively investigated.The waterborne polyurethane with branched structure can be successfully synthesized,according to FT-IR and ¹³C NMR analysis.The optimal process conditions are a reaction concentration of 50%and a degree of neutralization of 1.0.As the R value increases,the molecular weight gradually increases,and the distribution narrows,The emulsion’s appearance,particle size,and water resistance were all affected by DMPA,and as the concentration of the compound increased,the particle size and water resistance dropped.When the DMPA concentration is 2.0%,the polymer may be emulsified and dispersed,but the stability is poor.The properties of HWPU modified by HDI curing agent have improved noticeably,and the curing agent dosage is 3.0～4.0%.（2）Firstly,hyperbranched polyols（HP）were synthesized from IPDI,DMPA and DEOA,and the partially end-capped linear polyurethane prepolymers of HP and n-butanol were grafted by chain extension method to obtain a series of polyols with different HP contents HWPU lotion.The effects of HP additions and different soft segments on the basic properties of HWPU were focused on.The results showed that HP was successfully prepared by FT-IR and(~1H and ¹³C)NMR analysis.with the increase of HP content,the stability of the emulsion decreases,the particle size is between 180～445 nm,the tensile strength,water resistance,thermal stability The properties have been improved to varying degrees,and the film performance has been significantly improved.When the HP content is 4.0%,the emulsion is milky white,the particle size is 442.7 nm,the tensile strength is 23.6 MPa,the elongation at break is 473.4%,and the water absorption rate at 72 h is 11.8%.The hardness is H and the gloss is about 97°.At the same time,compared with polyester and polyether HWPU,PCD-HWPU film has higher mechanical strength and good flexibility.（3）The end groups of HWPU were modified and modified with hydroxyl-terminated silicone oil to prepare a series of hyperbranched waterbased polyurethanes（HWPUS）containing silicone.The basic properties of silicone modified HWPUS were systematically characterized.The research results show that with the increase of hydroxyl-terminated silicone oil content,the particle size of the emulsion gradually becomes larger,the stability becomes worse,and the water resistance of the film is significantly improved.The coating film has excellent adhesion,has little effect on its hardness,and is resistant to Ethanol properties have been significantly improved.When the content of hydroxyl-terminated silicone oil is 4.0%,the particle size of the emulsion reaches 450 nm,the tensile strength is22.6 MPa,and it has good flexibility and excellent water resistance.