Preparation And Properties Of Methacrylate Modified Waterborne Polyurethane Membrane

In this study. the process conditions of acrylate monomer modified waterborne polyurethane was investigated by using polyether type WPU as raw material. Effects of different acrylate monomers on properties of polyurethane were studied. Different side-chain based methacrylate modified polyurethane were synthesized to investigate the relationship between membrane structure and properties. To further improve the membrane property, a variety of monomers were used together to modify waterborne polyurethane. The results are as follows.（1） The optimum conditions acrylate modified waterborne polyurethane were: the reaction temperature was 80℃, HEA contents was 5wt%, reaction time was 5h and the initiator contents was 0.6wt%. While the copolymerization of WPU with different monomers under the optimum conditions, the results shown that: BA can improve the formation of the membrane, MA can significantly improve the stability ,St can significantly increase the membrane flux, MMA can effectively improve the stability of membrane and solubility selectivity, BMA can improve the dissolution of membrane,The solubility selectivity of DMA was smaller than that of BMA and MMA, The multifunctional TMPTMA modified membrane has obvious inhibitory effect of membrane swelling, but solubility selectivity factor was as high as 3.1.（2） A series of waterborne polyurethane （WPU） was modified by copolymerization of methacrylate （MMA,BMA,DMA） to separate benzene and cyclohexane. It was shown that the thermal stability of MMA modified membranes was significantly improved. The solubility selectivity factor increased from 1.4 to 2.1 and the separation factor increased from 2.5 to 3.2, as the weight ratio of MMA to WPU increased from 0:100 to 15:100.Nevertheless, the permeation flux decreased from 0.52 kg·m^-2.h"1 to 0.43 kg.m^-2.h^-1.With the increasing of side-chain length of the copolymerized n-alkyl methacrylate, the flux of membranes increased, but the separation factor decreased slightly. The activation energy of WPU A membranes increased from 25.86 kJ/mol to 31.24 kJ/mol corresponding to the WPU-MMA and WPU-DMA. The pervaporation activation energy of benzene and cyclohexane increased with side-chain length increased. It was more apparent for the cyclohexane.（3） The optimized proportion of functional monomer modified polyurethane membrane was BA:MA:St:MMA to 1.5:1.5:1:0.6. The thermal stability of the modified membrane was obviously improved, the separation flux of the modified membrane was greatly improved,and the separation factor was also improved. Polyfunctional TMPTMA lead to acrylate aggregation, resulting in the phase separation. With the increase of TMPTMA,membrane solubility selectivity increased from 2.2 to 3.1,the separation factor increased from 3.1 to 4.2 while the separation flux decreased from 0.90 kg.m^-2.h^-1 to 0.37 kg.m^-2.h^-1.