Among the earliest signs of degradation in cellulose triacetate cinematographic films is the generation of acetic acid due to hydrolytic deacetylation of the polymer, marked by an increase in the acidity of the films and emissions of acetic acid leading to a characteristic vinegar odour. We propose a mathematical model for predicting the onset of the vinegar syndrome which accounts for the autocatalytic effect of acetic acid on the deacetylation reaction. Model parameters are estimated from previously published experimental data from other research groups. These show free acidity changes in cellulose triacetate films subjected to accelerated ageing at temperatures of 70–100 °C. The model is validated against a different set of previously published experimental data of cellulose triacetate films aged at 21 °C and 35 °C, at 20, 35 and 50% relative humidity. The model demonstrates good quantitative agreement with the published experimental data. Predictions of film permanence at lower temperatures, similar to those present in the archives in which the films are typically stored, are made and compared with the predictions of film conservation guidelines. The results indicate that film permanence may be overestimated by existing guidelines, which do not account for autocatalysis in their modelling of the deacetylation rate. Our results suggest that cold storage, a common film conservation strategy, may be less effective at inhibiting degradation than previously thought. As cold storage typically requires film to be kept in confined spaces with limited air movement, conditions which promote autocatalysis, the inclusion of autocatalysis in our model is highly applicable to simulating this environment.

在三乙酸纤维素酯电影胶片中降解的最早迹象之一是由于聚合物的水解脱乙酰作用而产生的乙酸，其特征在于胶片的酸度增加和乙酸的散发导致醋味散发出特征。我们提出了一个数学模型来预测醋综合症的发作，这解释了乙酸对脱乙酰基反应的自动催化作用。模型参数是根据其他研究小组先前发布的实验数据估算得出的。这些表明三乙酸纤维素薄膜在70–100°C的温度下加速老化后的游离酸度变化。该模型针对一组先前发布的，在21°C和35°C下于20°C老化的三醋酸纤维素膜的实验数据进行了验证。35和50％的相对湿度。该模型证明与已发布的实验数据具有良好的定量一致性。与较低温度下的胶卷持久性的预测（类似于通常存储胶卷的档案中的预测）相比较，并与胶卷保存准则的预测相比较。结果表明，现有的准则可能会高估薄膜的持久性，在其对脱乙酰基率的建模中并未考虑自动催化作用。我们的结果表明，冷藏是一种常见的薄膜保存策略，其抑制降解的作用可能比以前认为的要差。由于冷藏通常需要将薄膜保持在空气流动受限的密闭空间中，因此会促进自催化，