The Preparation Of Water Swelling Elastomers Based On EPDM And Performance Research

In this paper, a series of performance testings and researches had been done to the EPDM based water swelling elastomer in order to obtain the compound of EPDM based water swelling elastomer that the requirement is higher water absorption expansion ratio, higher mechanical strength and lower mass loss ratio. Firstly, considering the mechanical strength of water swelling elastomer, we chose the EPDM rubber of higher ethylene content and mooney viscosity as base material and the packing as another base material in the water swelling elastomer, a series of experiments had been done to find the most appropriate variety and dosage of packing; secondly, the compatibility of EPDM and SAP was researched. In order to achieve higher water absorption ratio and lower mass loss ratio, we chose different kinds of compatilizer and observed compatibility after adding SAP in rubber base material; thirdly, the water absorption ratio, mechanical strength, mass loss ratio and so on had also been researched in different system of hydrophilic polyurethane materials. Then we changed the content of free NCO% and ratio of polyols to get the best formula of hydrophilic polyurethane material and selected more suitable formula in system for the next step to prepare the higher ratio water expansion elastomer; finally, we chose the appropriate EPDM rubber, variety and dosage of packing, amount of compatibilizer and the hydrophilic polyurethane material of better performance to prepare the water swelling elastomer, ultimately the water swelling rubber formula was determined according to the mechanical properties and water absorption performance of different vulcanization system.The concrete preparation process was as follows:(1) The selection of EPDM base material, through a series of mechanical properties testings and data analysis, EPDM539 was suitable for the water swelling elastomer rubber base material, and it was better to select ion rhodia Zeosil 175 MP silica and kaolin as packing.(2) As the increase of the amount of the SAP in EPDM base material, the mechanical properties declined gradually, the water absorption ratio and mass loss increased gradually; according to the SEM, with the increase of SAP, the compatibility between SAP and rubber base material became worse and worse and defect was also more and more; in the compatibility research of EPDM and SAP, we found that the mechanical properties and water absorption was better when the amount of compatilizer was 2 phr.(3) In the process of hydrophilic polyurethane material preparation and formula optimization, we found that P-23/P-35 system was more appropriate in the P-23 system and P-20/P-34 system was more appropriate in the P-20 system.(4) In the optimization process of ternary blend water swelling elastomer formula, the water swelling elastomer had better mechanical performance, higher water absorption ratio and lower mass loss ratio on condition that P-23/P-35 ratio of polyols was 70/30, free NCO% content was 4.0%, vulcanization system was S/TT (1.5/1.5); and we found that the water swelling elastomer had better comprehensive mechanical performance, higher water absorption ratio and lower mass loss ratio on condition that P-20/P-34 ratio of polyols was 70/30, free NCO% content was 3.5%, vulcanization system was S/CZ (3/1), the amount of antioxidant 1010 was 2 phr.