Study On Preparation And Application Of Natural Rubber Composite Sponge

Natural rubber latex sponge(NRS)is a kind of 3D porous material,the continuous pore structure makes the NRS have many good properties,such as strong elasticity,good cushioning,thermal-insulation,sound-insulation,creep resistance and so on.It has been widely used in aviation industry,automobile industry,chemical industry,medical devices and other fields.As a big manufacturing country,China produces massive sponge products every year,and also produces a large number of sponge waste.How to reuse the waste is an urgent problem.In this paper,the functional NRS materials were prepared by modification of NRS,which provided a solution for the reuse of NRs waste.The main research contents are as follows:1.NRS was prepared by Dunlop method through mechanical foaming,vulcanization and drying.The microstructure of NRS was characterized by scanning electron microscope(SEM).In NRS,micro pores with diameters ranging from tens to hundreds of microns could be observed.The pores were continuous and connected.The excellent 3D pore structure created conditions for the later functional modification.2.PVA/P(AA-AM)/NRS absorbent and water-retaining materials with interpenetrating network structure were prepared by one-step method using NRS as framework.The structure of the composite was characterized by FTIR,TG and SEM.Acrylic acid(AA)and acrylamide(AM)were used as monomers,N,N'-methylene bisacrylamide(MBA)as crosslinking agent,and ammonium persulfate(APS)was used as initiator to polymerize to form the first network structure;polyvinyl alcohol(PVA)was crosslinked by borax to form the second network structure.The effects of the amount of acrylic acid,acrylamide,ammonium persulfate,N,N'-methylene bisacrylamide and PVA on the water absorption and retention properties of PVA/P(AA-AM)/NRS composites were studied.The water absorption rate of the water-absorbing and water-retaining sponge is up to 128 g/g.After fully absorbing water,in a cool place at room temperature,under simulated sunlight and extreme tropical environmental conditions,the water retention rates after 36 hours are respectively 83%,70%and 54%;repeated many times The water retention rate of the sponge is basically unchanged after use.It is expected to be used as water retaining agent in agriculture or thermal insulation materials for building roof.3.Polydopamine(PDA),a photothermal conversion material with wide band absorption,was in-situ coated on the NRS substrate.Through the self polymerization of dopamine,a layer of PDA was coated on the surface of NRS to prepare a PDA functional sponge(PNRS).Scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and ultraviolet visible near infrared absorption spectroscopy(UV Vis NIR)confirmed that the surface of NRS was covered with a layer of PDA,and the resulting PNRS had a wide band absorption ability.The evaporation rate of the device assembled with PNRS is 1.35 kg m^-2h^-1(1 sun=1 k W m^-2),and the energy conversion efficiency is 84.6%.After 8 hours of continuous irradiation,the evaporation was still high,and reaching 10.4 kg m^-2.In addition,PNRS also has higher evaporation rate in corrosive liquids(1 mol L^-1H₂SO₄and 0.5 mol L^-1Na OH).This stable and efficient photothermal material is expected to have a good application prospect in seawater desalination,wastewater treatment and other fields.The combination of the above two materials is expected to further broaden the scope of application,such as providing fresh water resources for tropical islands,heat insulation,soilless cultivation of vegetables and so on.It can greatly improve the living environment of officers and soldiers stationed on the island,and reduce the pressure of logistics support.