【作者】 陈强；

【导师】 赵永仙；

【作者基本信息】 青岛科技大学 ， 材料工程（专业学位）， 2021， 硕士

【摘要】 本文对不同牌号的三元乙丙橡胶(EPDM)进行性能评价和选择,选出符合GB 18173.1-2006高分子防水材料EPDM防水材料标准的橡胶牌号EPDM-3760p。并对EPDM-3760p的半有效硫磺硫化和DCP过氧化物硫化两种硫化体系硫化胶,进行了热空气老化、耐酸、碱老化三种老化。探究了力学性能、表面性能以及热稳定性等随老化时间的变化规律。采用溶胀法交联密度分析、力学性能分析、体式显微镜、热重分析仪(TGA)、傅里叶红外光谱仪(FTIR)、接触角测量仪等仪器分析表征了老化后EPDM硫化胶结构和性能的变化。随着热氧老化时间的增加,EPDM交联密度、硬度、拉伸强度均增加,过氧化物硫化的EPDM硫化胶的老化系数均大于1,老化系数随着老化时间增加变化不大;硫磺硫化的EPDM硫化胶的老化系数均小于1,且随着老化时间的增加老化系数逐渐降低。EPDM橡胶热失重分为三个阶段:第一阶段高挥发性物质(增塑剂等)的挥发,第二阶段中低挥发性物质的分解(EPDM橡胶基体),第三阶段炭黑等物质的缓慢燃烧。第一阶段热稳定性能随着老化时间的增加呈先增加后降低的趋势,DCP硫化的EPDM橡胶的耐热空气老化性能较硫磺硫化的EPDM橡胶要好,原因是DCP硫化的EPDM产生的C-C键键能大于硫磺硫化的单硫键、多硫键。老化后羟基含量逐渐增加、羰基指数逐渐增加、老化是交联和断链的共同作用。EPDM橡胶在10%浓度Na OH和10%浓度HCl条件下老化后交联密度、拉伸强度变化不明显,扯断伸长率以及300%定伸应力老化前期无明显规律,5天之后逐渐下降。老化后的显著变化主要体现在表面性能上,随着老化时间的增加,接触角均减小,表面性能逐渐向亲水性转变;硫磺硫化的EPDM硫化胶在10%浓度Na OH和10%浓度HCl条件下接触角下降程度均小于DCP过氧化物硫化的EPDM橡胶,说明DCP过氧化物硫化的EPDM橡胶耐酸碱性要优于硫磺硫化的EPDM橡胶;在10%浓度HCl条件下EPDM橡胶接触角减小程度均小于10%浓度Na OH环境下的EPDM,硫磺硫化的EPDM橡胶拉伸断裂试样表面裂纹程度大于DCP过氧化物硫化的EPDM橡胶,说明EPDM橡胶的耐酸性更好,耐碱性更差;防老剂RD/4010NA的加入会抑制EPDM橡胶在酸性条件下的老化。红外光谱分析结果表明,第三单体ENB中C=C双键在酸和碱条件下,会发生水解,从而导致的EPDM的降解,使得其羟基和酮的含量增加,EPDM在酸和碱条件下降解会从橡胶表面延续到内部,影响EPDM橡胶整体的稳定性。更多还原

【Abstract】 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.更多还原