摘要
为探究微胶囊对沥青性能的影响,通过正交试验,探明合成脲醛(三聚氰胺-尿素-甲醛)树脂壳材和正十四烷芯材对相变微胶囊性能的影响,解析其最佳制备工艺;采用差示扫描量热仪(DSC)、动态剪切流变试验仪(DSR)等实验手段,研究相变微胶囊改性沥青(相变沥青)的功能性.结果表明,微胶囊最佳制备工艺为乳化剂浓度7％,乳化转速2 000r/min,芯材与壁材质量比1∶1,油水体积比1∶7,合成时间90 min,合成温度80 ℃,此条件下制备的微胶囊潜热为117 J/g;微胶囊壳材密封性较好,能够在沥青中稳定存在,满足沥青施工温度区间要求;相变沥青放热区间为-7.1～-17.9 ℃,吸热区间为2.3～13.5 ℃,当微胶囊掺量为7％时,相变沥青相变焓为5.258 J/g;相变微胶囊能够有效延缓沥青硬化过程,且在常温条件下保持稳定,具有应用潜力.
Abstract
In this study,the impact of phase-change microcapsules(PCM)on asphalt performance was investigated through a series of orthogonal experiments.These experiments focus on the evaluation of the effect of the urea-formalde-hyde(melamine-urea-formaldehyde)resin as a shell material and n-tetradecane as a core material on the synthetic efficien-cy of PCM.The optimal preparation process for PCM was analyzed.Differential scanning calorimetry and dynamic shear rheology were employed to assess the performance of the PCM-modified asphalt(referring to as phase change bitu-men).The findings indicated that the most effective synthetic parameters were determined for PCM at an emulsifier con-centration of 7 wt.％,an emulsification speed of 2 000 r/min,a mass ratio of core to wall material of 1∶1,a 1∶7 oil-to-water volume ratio,a synthetic time of 90 min,and a reaction temperature of 80 ℃.Under such conditions,PCM exhib-ited a latent heat of 117 J/g.Furthermore,the microcapsule shell presented excellent sealing properties,ensuring the sta-bility of asphalt within the range required for construction temperature.The PCM-modified asphalt showed an exother-mic interval from-7.1 to-17.9 ℃ and an endothermic interval from 2.3 to 13.5 ℃.The PCM-modified asphalt pre-sented a phase-change enthalpy of 5.1 J/g at a microcapsule concentration of 7 wt.％.More importantly,the incorpora-tion of PCM effectively slowed down the hardening process of the PCM-modified asphalt and maintained its stability at room temperature.The developed phase-change asphalt exhibits great potential for application.
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