Study On The Synthesis And Expansion Process Of Water Swellable Polyurethane Elastomers

The water-swellable elastomer which has dual function of the elastic sealing and the water swelling, is a new functional polymer materials. While maintaining the rubber high elasticity, it has a performance of the rapid absorption and water retention. In this paper, using prepolymer method, by changing the type of raw materials for preparing a polyurethane elastomer(PUE) so that it can meet with the industrial application.(1) Selected the different molecular polyethylene glycol (PEG) as a soft segment, and T-100/MOCA as a hard segment prepared different NCO%of PUE.①Various physical properties tests show that:PUE was made by PEG-4000,its expansion velocity is slow, but it can maintain good in the expansion process, the retention rate of performance is better after recovery, with the increase of the hardness of water, the expansion velocity and the maximum expansion ratio for the same sample is significantly weakened;②DSC curves show that:the samples were treat by different solvents,it just destroyed the hydrogen bonds between the soft and hard segments,which had less impact on the main chain structure of polymer(2) Prepared prepolymer by PEG-4000and T-100, then selected DMTDA, TIPA as chain extender, synthesis different NCO%of PUE.①The physical performance tests show:DMTDA type of PUE’s overall performance was better than the TIPA type, performance remained well after various processing.②DSC and IR tested show that: When NCO%is5%, DMTDA-type PUE had good reusability. For TIPA type of PUE, although the integrity of the network structure of the molecules is improved, the obvious effect of the swelling of the polymer, it is not conducive to repeated use.(3) Prepared prepolymer by PEG-4000and T-100, select the different ratios of MOCA/DEG as a chain extender, and fixing NCO%is5%.①Physical performance tests show:with increases of DEG content, the mechanical properties of PUE gradually weakened, the expansion and recovery rate are gradually increased. When the ratio of MOCA/DEG is4/1or3/2, PUE has better overall performance.②Using DSC, IR, SEM and EDS tested the PUE after treatment which made by the ratio of MOCA/DEG is4/1or3/2. The results provide strong proof for reuse; SEM and EDS tests show:in the expansion process, the inorganic ions go into the polymer network, and form a complete crystal structure.③Study of the expansion process by DSC show that:the first suction process is bound to frozen water (also known as bonded water of crystallization), when it reaches the saturated adsorption, it start the process of free water.