Abstract: The decomposition temperature of sodium bicarbonate with different mesh number was studied. Five modifiers，including stearic acid and erucamide，were used to modify sodium bicarbonate by melting method and solution method. The effects of modification were evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The results showed that the mesh number of sodium bicarbonate has influence on its decomposition temperature. The organic coating and modification of sodium bicarbonate can increase the initial decomposition temperature，narrow the range of decomposition temperature and improve the decomposition rate. All of these can be used in the processing of foam plastic. Sodium bicarbonate was modified by melting-method with a mass ratio of 1∶0.5 obtained in the optimized condition，in which its initial decomposition temperature is increased from 115 ℃ to 178 ℃，and its decomposition temperature range is narrowed from 61 ℃ to 25 ℃. The most probable mechanism functions of the thermal decomposition of sodium bicarbonate and modified sodium bicarbonate agree with Avrami-Erofeev equations. The addition of modifiers can increase the nucleation growth factor n and apparent activation energy Ea.

Key words: sodium bicarbonate, organic coating, blowing agent, thermal decomposition

摘要： 考察了不同目数下碳酸氢钠的热分解温度；采用熔融法和溶液法，使用硬脂酸、芥酸酰胺等5种改性剂对碳酸氢钠进行改性，利用DSC和TG评价其改性效果。结果表明：碳酸氢钠的目数对其热分解温度有一定影响；采用有机包覆改性碳酸氢钠的方法能够有效提高其分解温度，缩短分解区间，提高分解速率，从而应用于泡沫塑料加工；当NaHCO3∶硬脂酸的质量比为1∶0.5时，采用熔融法所得的改性碳酸氢钠的起始分解温度由115 ℃提高至178 ℃，分解区间由61 ℃缩短至25 ℃；改性前后碳酸氢钠的热分解反应都符合“成核与核增长”机理中的Avrami-Erofeev方程，改性剂的添加会导致核成长因子n的增加，改性碳酸氢钠的活化能Ea也有所 提高。

关键词: 碳酸氢钠, 有机包覆, 发泡剂, 热分解