Synthesis And Application Of High Oil Absorptive Resin Based On EPDM Rubber

The structure, oil-absorptive properties and mechanical properties of ethylene - propylene - diene (EPDM)/4-tert-butylstyrene (tBS) crosslinked oil absorptive resins were studied theoretically and experimentally in this dissertation.From the point of view of molecule design, EPDM and tBS, a soft long-chain macromolecule and a rigid short-chain little molecule respectively, were chosen as main monomers to improve the structure of oil-absorptive resins, reduce the steric hindrance, enhance the oil absorbency, oil absorptive rate and mechanical behaviors. After such difficulties as EPDM solution being high viscosity, prone to coalescence and sensitive to temperature change being resolved, a series of oil-absorptive resin beads were synthesized by suspension copolymerization under the protection of gelatine, tricalcium phosphate and sodium dodecylsulfate (SDS) at an optimum ratio. The influences of monomers, crosslink agents, initiators, dispersion agents, pore-forming agents, temperature and water phase to oil phase ratio on the structure, oil-absorptive properties and mechanical behaviors of oil-absorptive resins were studied, and the recipe and operation conditions were optimized as follows: 3wt% divinylbenzene (DVB) crosslinker, 1wt% benzoyl peroxide (BPO) initiator at 80℃for 7-8h. The ratio of tBS to EPDM is 40:60 wt%. The volume ratio of toluene to cyclohexane is 4:1, and the total volume is 30ml. The proportion of gelatine to tricalcium phosphate is 0.1g/0.05g, and the stirring speed is 500r/min. Water phase to oil phase ratio is 5:1. The maximum oil absorbency to carbon tetrachloride, chloroform, cyclohexane, kerosene, toluene are 51.68, 35.00, 25.83, 27.50 and 22.80g/g, respectively. The oil absorptive rate constant K are 66.64 and 199.93h^-1 for kerosene and toluene, respectively, and the oil-absorbing process obeys the first-order kinetics well.Based on the unsaturated bond on EPDM side chain, a kind of weak chemical crosslinking may be introduced into strong chemical crosslink network. By using such methods as analysis of double bond content, thin-layer chromatography, infrared spectra and differential scanning calorimeter, the double bond in EPDM side chain was found to indeed react with monomers acting as chemical crosslinker. Additionally, as a long-chain macromolecule, EPDM may bring forth physical crosslinking arise from chain entanglements. Therefore, the structure model of oil-absorptive resins was proposed, in which chemical crosslink network and physical crosslink network formed by chain entanglements were cooperated each other. The purpose of adding tBS was to adjust the mechanical properties of resins. It was found that adding tBS enhances the compressive strength of oil gels on the basis of maintaining the tensile strength and elongation at break, which is of great importance for industry application of oil-absorption resins.To increase oil-absorptive rate, pore-forming agents were used in polymerization process. The influences of good solvent (toluene) and poor solvent (cyclohexane) on surface morphology of oil gels were investigated by scanning electron microscopy, and the corresponding oil -absorptive behaviors and compressive properties were examined. It was observed that the bigger toluene content, the smaller average pore size and oil-absorptive rate, and the bigger tensile strength and elongation at break. The shape and size of pores, oil absorbency and compressive properties were optimized at a volume ratio of toluene to cyclohexane equal to 4:1.Based on non-biodegradability of synthetic materials, expensive incineration and environmentally undesirable landfill disposal, the oleic acid coated magnetite (Fe₃O₄) particles were chosen to prepare magnetic composite resins, thus which would be recovered conveniently and rapidly after absorption by magetic separation techniques. The research results indicated that adding magnetic particles enhances the mechanical behaviors of oil-absorptive resins, but seriously worsens the oil-absorptive behaviors.Furthermore, The oil-absorptive resins were applied to the treatment of environmental hormone (styrene) in water and sulfur dioxide adsorption. The results indicated that the sorption efficiency of static and dynamic sorption are 99.47% and 96.25%, respectively. The oil absorptive resins modified with ethylenediamine can adsorb more sulfur dioxide, and the maximum amount reaches 680mg/g.