碳酸氢钠的改性及其对聚丙烯发泡行为的影响

Modification of sodium bicarbonate and its effects on polypropylene foaming behaviors

为了提高碳酸氢钠的分解温度,使其满足于聚烯烃材料的功能化需求,设计“一步法”和“两步法”合成技术,以碳酸氢钠(SB)为核,环氧树脂(EP)为壁材,制备得到EP@SB微“胶囊”。利用红外(FT-IR)、热重(TG)、扫描电镜(SEM)等技术,研究不同方法改性后碳酸氢钠分解温度、形貌和性能的变化,并探究改性碳酸氢钠对聚丙烯(PP)发泡行为的影响。结果表明:改性后碳酸氢钠的分解温度相比纯的碳酸氢钠提高了36℃,分解温度区间由67降为25℃;两步法改性得到的EP@SB比表面积更大、分散性更好,且相比未改性碳酸氢钠,在聚丙烯(PP)中的发泡行为改善明显,平均泡孔直径变小、发泡倍率提高将近3.2%。

In order to improve decomposition temperature of sodium bicarbonate to meet requirements of polyolefin functionalization,a new epoxy resin@sodium bicarbonate(EP@SB)microcapsules using SB as core and EP as shell were synthesized by one-step or two-step methods.The structure and properties of sodium bicarbonate modified by different methods were studied by SEM,FTIR and TG,and the effect of modified sodium bicarbonate on polypropylene(PP)foaming was investigated.The results indicate that the decomposition temperature of the modified sodium bicarbonate is 36℃higher than that of pure sodium bicarbonate,and the decomposition temperature range is also reduced from 67 to 25℃.The EP@SB modified by a two-step method had a larger specific surface area and better dispersibility,and the foaming behavior of the modified EP@SB in polypropylene(PP)was obviously improved with the average cell diameter became smaller and the foaming ratio increased by nearly 3.2%.