Kinetics Of Urethane Reaction And Synthesis Of Novel Polyurethane

Polyurethane materials have a wide range of applications in our daily lives.With the continuing development of the society,people have higher and higher requirements to the properties of polyurethane materials.In this thesis,the effects of solvents and temperature on the reaction of benzyl alcohol and phenyl isocyanate have been investigated by using in-situ FTIR.On the basis of this study,a new water-based polyurethane fatliquor-retanning agent and hyperbranched polyesters were synthesized.And hyperbranched polyesters were modified by isocyanates and other compounds.Main contents of this thesis are as follows:(1)The reaction of benzyl alcohol and phenyl isocyanate was monitored by in-situ FTIR.The effects of solvents(1,2-dichloroethane,N,N-dimethylformamide)and the reaction temperature on the reaction were investigated.The study showed that the reaction rate constant increased with the increase of temperature in both solvents.The reaction rate constant in N,N-dimethylformamide was larger than that in 1,2-dichloroethane and the activation energy was lower.It indicated that the solvent N,N-dimethyl formamide had a certain catalytic effect on the reaction,and verified the mechanism put forward by Baker.(2)Firstly using pentaerythritol as "core" and dimethylol propionic acid as branched monomer,different algebraic hyperbranched polyesters were synthesized by stepwise polymerization individually.And modified with hexamethylene diisocyanate-hydroxyethyl acrylate(HDI-HEA)and succinic anhydride to obtain a series of carboxyl group-containing hyperbranched polyester acrylate oligomers.And the structure and properties were characterized and analyzed by means of infrared spectroscopy,nuclear magnetic resonance spectroscopy,UV spectroscopy,differential scanning calorimetry and thermogravimetric analysis.UV-vis results indicated that the synthetic oligomer had strong UV absorption at 210 nm.The DSC results showed that all synthetic oligomers had a lower glass transition temperature.TGA analysis indicated that the thermal stability increased with the increase of generation hyperbranched polyester acrylate oligomer cured film.(3)2,4-tolylene diisocyanate(TDI)as the starting material,tartaric acid(TA)for the retanning agent,GLycerol Monostearate as the fatliquor,stearyl alcohol as the capping agent,a new water-based polyurethane fatliquor-retanning agent was synthesized.The synthesized aqueous polyurethane structure contained both a plurality of carboxyl groups and long chain alkyl ester side chains.Therefore,it had been made up for the defect of poor performance due to less filler content caused by carboxyl in the past synthesis of polyurethane retanning fatliquoring agents.As the Long-chain alkyl ester provided the function of refatting so that the leather fibers had good inter-lubricating properties.