CAJ | 학술논문

绝缘纸无定形区的玻璃转化温度是其热稳定性的重要标度之一。为研究变压器绝缘纸的玻璃转化过程的微观机理,继而挖掘其中的热老化信息,利用分子动力学对绝缘纸纯纤维素、纤维素-水两个模型的玻璃转化过程进行了模拟。用比体积-温度曲线法确定了纯纤维素和纤维素-水模型的玻璃化转变温度分别为448、418K。模拟结果表明,玻璃转化过程中,绝缘纸纤维素链的运动和机械特性均发生突变,400～500K之间自由体积的突变给纤维素链运动提供了更多空间,导致其发生玻璃化转变;水分子浸入无定型区可以破坏纤维素链间的氢键,显著地降低玻璃转化温度,影响绝缘纸热稳定性。
절연지무정형구적파리전화온도시기열은정성적중요표도지일。위연구변압기절연지적파리전화과정적미관궤리,계이알굴기중적열노화신식,이용분자동역학대절연지순섬유소、섬유소-수량개모형적파리전화과정진행료모의。용비체적-온도곡선법학정료순섬유소화섬유소-수모형적파리화전변온도분별위448、418K。모의결과표명,파리전화과정중,절연지섬유소련적운동화궤계특성균발생돌변,400～500K지간자유체적적돌변급섬유소련운동제공료경다공간,도치기발생파리화전변;수분자침입무정형구가이파배섬유소련간적경건,현저지강저파리전화온도,영향절연지열은정성。
The glass transition temperature in amorphous region of insulation paper is one of the most important characteristics for its thermal stability. In order to study the microscopic mechanism of the glass transition process for transformer insulation paper, which may provide some information for thermal aging, molecular dynamics simulations were performed on two micro-structural models, pure amorphous cellulose, amorphous cellulose with water. Using the method of specific volume versus temperature curve, the glass transition temperatures of pure cellulose and cellulose-water models were determined as 448 K and 418 K respectively. Simulation results show that, during the glass transition process, both the chain movement and mechanical properties of cellulose change significantly. The sudden change of free volume between 400 K and 450 K, which provides more space for chain movement, is the nature of glass transition. Water molecules immersed in amorphous region of insulation paper can disrupt hydrogen bonds between cellulose chains, leading to a significant reduction in glass transition temperature and affecting the thermal stability of the insulation paper.