推进剂组分对聚醚聚氨酯粘合剂热氧降解的影响 (Ⅰ)硝酸酯增塑剂的影响

EFFECT OF PROPELLANT COMPONENTS ON DEGRADATION OF POLYETHER URETHANE BINDER (Ⅰ)THE EFFECT OF NITRATE ESTERS

关键词:  聚醚推进剂  聚氨酯推进剂  硝酸酯  热氧降解  傅立叶谱仪  核磁共振

Key words:  Polyether propellant  Polyurethane propellant  Ester nitrate  Thermooxidation + Fouxier spectrometer  Nuclearmagnetic resonance

摘要:

采用傅立叶红外光谱和核磁共振技术，研究了硝化甘油（ＮＧ）和１，２，４－丁三醇三硝酸酯（ＢＴＴＮ）两种硝酸酯增塑后的聚醚聚氨酯在空气中９０°Ｃ下的热氧降解。结果表明：ＮＧ，ＢＴＴＮ在聚氨酯粘合剂中的分解产物主要为醇类。这些小分子醇参与了聚氨酯硬段的重聚合反应，形成氨基甲酸酯结构；硝酸酯对聚氨酯粘合剂的热氧降解表现出某种稳定作用，并改变了软段产物结构，使甲酸酯和叔碳结构相对增加；硝酸酯分解产生的ＮＯ２自由基可能与软段降解产生的过氧化氢反应形成硝酸，从而加速了硝酸酯的水解。

Abstract:

The effect of two nitrate esters(NG,BTTN)on the degradation of EO/THF copolyether urethane binder was studied by structural analysis of degradation products with FT IR and NMR methods.Alcohols were the main degradation products of these two nitrate esters.Structural confirmation proved that these alcohols were mainly generated from the hydrolysis of nitrate esters and subsequently underwent the repolymerization with isocyanates to form carbamates.It was also surprisingly found that nitrate esters showed some stabilizing effect on the polyurethane binder but resulted in high proportion of formates and tertiary carbons in the degradation products of polyurethane and that no efficient absorption of nitric free radicals by centralite Ⅱ was found on the current experimental condition.To ecplain these observations,a mechanism was suggested that the nitric free radicals derived from the decomposition of nitrate esters reacted with peroxides to form nitric acid,which accelerated the hydrolysis of nitrate esters.