Investigation on foaming and secondary reactions with a novel visual equipment and impacts on thermal analysis

The foaming occurring in thermal analysis often results in mass signal fluctuation or delay and finally leads to misunderstanding of reaction mechanism. However, it is very difficult to predict when and how foaming occurs if there is no video instrument for in-situ observation of thermal reactions. In this study, foaming was confirmed by a novel micro-video equipment of self-assembly with an ultra-rapid cooling system, which can tolerate high temperature and continuous heating. The video of heating tartaric acid continuously recorded a complete process of foaming between 200 and 300 ℃ and thermal analysis indicated the formation mechanism of foaming. The findings are consistent with the consequence of viscosity testing. The secondary reactions of evolving gases were simultaneously recorded by the video instrument, which revealed that foaming was the cause of mass information fluctuation or lag.