TG–FTIR combined technology was used to study the degradation process and gas phase products of epoxy glass fiber reinforced plastic (glass fiber reinforced plastic) under the atmospheres of high purity nitrogen. The pyrolysis characteristics of epoxy glass fiber reinforced plastic were measured under different heating rates (5, 10, 15, 20 °C min−1) from 25 to 1000 °C. The thermogravimetric analyzer (TG) and differential thermogravimetric analyzer (DTG) curves show that the initial temperature, terminal temperature, and temperature of maximum weight loss rate in the pyrolysis reaction phase all move towards high temperature, as the heating rate increases. Epoxy glass fiber reinforced plastic has two stages of thermal weightlessness. The temperature range of the first stage of weight loss is 290–460 °C. The second stage is 460–1000 °C. The above two weight loss stages are caused by pyrolysis of the epoxy resin matrix, and the glass fiber will not decompose. The dynamic parameters of glass fiber reinforced plastic were obtained through the Kissinger-Akahira-Sunose (KAS), Flynn–Wall-Ozawa (FWO) and advanced Vyazovkin methods in model-free and the Coats–Redfern (CR) method in model fitting. FTIR spectrum result shows that the main components of the product gas are CO2, H2O, carbonyl components, and aromatic components during its pyrolysis.

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This study presents the experimental methods of microwave drying and hot air drying of rice to simultaneously improve the dry storage effect of rice, reduce the mouldy and spoilage of rice, and measure the moisture content, water activity and temperature changes. A thermal imaging camera was used to photograph the temperature distribution of rice at different times to study the changing law of rice drying characteristics and analyse the relationship between rice water activity and drying speed. Results show that the changes in the moisture content and water activity of rice are inversely proportional with time. A 400 W microwave drying has a more pronounced heating effect on rice than 850 W hot air drying. The efficiency of the first 20 min of rice drying is better than that of the last 20 min. The highest temperature of 40 • C was reached after microwave drying for 8 min, while nearly 40 • C was reached after hot air drying for 56 min. These results can be applied to further analyse the influence of different drying methods on rice water activity and guide the reduction of bacterial propagation in rice and the improvement of the quality of rice. This work provides a theoretical basis for choosing the optimal drying method. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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