Study On Preparation And Aging Peoperties Of EPDM Waterproofing Membrane

In this paper,the performance evaluation and selection of different grades of ethylene propylene diene rubber(EPDM)are carried out,and the rubber grade EPDM-3760 p that meets the GB 18173.1-2006 polymer waterproof material EPDM waterproof material standard is selected.The two vulcanization systems of EPDM semi-effective sulfur vulcanization and DCP peroxide vulcanization have been subjected to three types of aging: hot air aging,acid resistance and alkali aging.The changes of mechanical properties,surface properties and thermal stability with aging time are explored.The swelling method was used to analyze the crosslink density analysis,mechanical property analysis,stereo microscope,thermogravimetric analyzer(TGA),Fourier infrared spectrometer(FTIR),contact angle measuring instrument and other instruments to analyze and characterize the changes in the structure and performance of EPDM after aging.With the increase of thermal oxygen aging time,EPDM cross-linking density,hardness,and tensile strength all increase.The aging coefficient of peroxide-vulcanized EPDM is greater than 1,and the aging coefficient does not change much with the increase of aging time;sulfur-vulcanized EPDM is aging The coefficients are all less than 1,and the aging coefficient gradually decreases as the aging time increases.EPDM rubber thermal weight loss is divided into three stages: the first stage is the volatilization of highly volatile substances(plasticizers.),the second stage is the decomposition of low-volatility substances(EPDM rubber matrix),and the third stage is carbon black and other substances.Burn slowly.The thermal stability of the first stage increases first and then decreases with the increase of aging time.The heat-resistant air aging performance of DCP-vulcanized EPDM rubber is better than that of sulfur-vulcanized EPDM rubber.The reason is the CC bond produced by DCP-vulcanized EPDM.The single sulfur bond and polysulfide bond that can be greater than sulfur vulcanization.After aging,the hydroxyl content gradually increases,the carbonyl index gradually increases,and aging is the combined effect of cross-linking and chain scissionEPDM rubber has no obvious change in cross-linking density and tensile strength after aging under the conditions of 10% Na OH and 10% HCl,and the law of elongation at break and 300% tensile stress is not obvious.The significant changes after aging are mainly reflected in the surface properties.As the aging time increases,the contact angle decreases and the surface properties gradually change to hydrophilicity;sulfurvulcanized EPDM under the conditions of 10% Na OH and 10% HCl The decrease in contact angle is less than that of EPDM rubber vulcanized by DCP peroxide,indicating that the acid and alkali resistance of EPDM rubber vulcanized by DCP peroxide is better than that of sulfur-vulcanized EPDM rubber;the contact angle of EPDM rubber is reduced under the condition of 10% HCl.The degree is less than that of EPDM under10% concentration Na OH environment,and the surface crack of sulfur-vulcanized EPDM rubber tensile fracture sample is greater than that of DCP peroxide-vulcanized EPDM rubber,indicating that EPDM rubber has better acid resistance and worse alkali resistance;The addition of antioxidant RD/4010 NA will inhibit the aging of EPDM rubber under acidic conditions.The results of infrared spectroscopy analysis showed that the C=C double bond at the third single ENB under acid-base conditions will produce desulfurization and hydrolysis,which will lead to the degradation of EPDM and the degradation of hydroxyl and ketones.As the content increases,the degradation of EPDM will continue from the surface to the inside of the body,affecting the stability of EPDM rubber.