丁羟包覆层老化宏微观特性相关性及贮存寿命预估

Correlation between macroscopic microscopic aging properties and lifetime prediction of hydroxyl-terminated polybutadiene inhibitor

  • 摘要: 为了研究固体火箭发动机中丁羟包覆层的宏微观特性相关性并准确预估其材料的贮存寿命,开展了50℃、60℃、70℃和80℃温度下的加速老化试验,建立了交联密度和最大延伸率的相关性函数关系,并用对数模型、幂函数模型和指数模型研究了交联密度随贮存时间的变化规律。以交联密度为老化性能表征量,选用修正Arrhenius法预估了试样的常温贮存寿命。结果表明,α=0.3时的幂函数模型能够较好地描述丁羟包覆层交联密度的变化规律,修正Arrhenius法求得的表观活化能与温度之间具有线性关系。分别以最大延伸率下降50%时的线性函数和二次多项式对应的交联密度值作为失效判据,预估丁羟包覆层的在常温298.15 K下的贮存寿命为17.38年和16.14年,结果与用最大延伸率预估的寿命具有很好的一致性,且能够满足包覆层的老化性能要求。

     

    Abstract: To study the correlation between the macroscopic and microscopic properties of the hydroxyl-terminated polybutadiene inhibitor in solid rocket motor, as well as accurately predict the storage life of the material, accelerated aging tests at 50℃, 60℃, 70℃ and 80℃ were carried out. The correlation functions about crosslink density and maximum elongation were built, and logarithmic model, power function model and exponential model were used to study how the crosslink density varied with storage time. The crosslink density was selected to describe the aging properties, and the modified Arrhenius method was chosen to predict the storage life of hydroxyl-terminated polybutadiene inhibitor under room temperature. The results show that the power function model with α=0.3 can describe the variation law of crosslink density well. The apparent activation energy of the aging reaction obtained by modified Arrhenius method has a linear relationship with temperature. Taking the crosslink densities as the failure criterion, which are calculated by linear equation and quadratic polynomial respectively when the maximum elongation decrease of 50%, the estimated storage lifetime of the hydroxyl-terminated polybutadiene inhibitor at 298.15 K are 17.38 years and 16.14 years, identical to that when solved with the maximum elongation. Besides, the predicted lifetime can meet the aging performance requirements of the inhibitor.

     

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