双键含量对醇酸树脂固化热的影响

Effect of double bond content on the heat of curing of alkyd resin

醇酸树脂的固化是双键与氧的交联反应,固化热效应可能导致漆渣自燃。为找出双键含量与固化热的关系,通过调节顺丁烯二酸酐(顺酐)和邻苯二甲酸酐(苯酐)用量制备了不同双键含量的醇酸树脂,用化学滴定法测得树脂中双键含量随顺酐含用量增大而线性增加。红外光谱测试表明树脂干燥过程中碳碳双键逐渐消失而交联固化,并根据树脂固化前后的氧弹燃烧热值得到其固化热,结果表明固化放热量随双键含量的增加而线性增长,且树脂中每增加1 mol双键固化放热量增加7478.5kJ。

The curing of alkyd resin is the crosslinking reaction of oxygen with double bond and the heat of curing may lead to spontaneous combustion of waste paint, In order to find out the relationship between double bond content and heat of curing, alkyd resins with different contents of double bond were synthesized by adjusting the amounts of phthalic anhydride and maleic anhydride. The content of double bond was determined by chemical titration. It was found that the content of double bond is increased linearly with increasing maleic anhydride content. Infrared spectroscopy results showed that the double bond gradually disappears as the alkyd resin dries. The heat of curing was obtained by measuring the heat of combustion of resins before and after curing. The results showed that as the content of double bond increases, the exothermic heat of curing increases linearly. An increase of 1 mol double bond corresponds to 7478.5kJ exothermic heat of curing.