发泡工艺参数对酚醛树脂基泡沫炭孔结构的影响

Influence of foaming process parameters on the pore structure of phenolic resin-based carbon foam

以热塑性酚醛树脂为原料,无水乙醇溶液为发泡剂,通过液相低压发泡工艺,改变酚醛树脂前驱体的发泡条件,研究树脂浓度、发泡压力、发泡温度、固化剂含量对其发泡行为及泡沫炭孔结构的影响及其规律。结果表明,随着树脂浓度的增大,泡沫炭的孔径变小,分布更加均匀;固化剂(六亚甲基四胺)最适添加量为10%;孔径结构随着发泡压力的增大呈现规律性变化,合理的发泡压力范围为1.5~2.0 MPa;遵循成核发泡机制,发泡温区在170~190℃范围内可制备完整不易开裂的泡沫炭。

Phenolic resin-based foamed carbon is a kind of high-strength, lightweight and heat-insulating carbon material widely used. Controlling the synthesis conditions of the precursor is the key process for preparing phenolic resin-based foamed carbon. Using thermoplastic phenolic resin as raw material and anhydrous ethanol solution as foaming agent, through the liquid phase low pressure foaming process, the phenolic resin-based carbon foams are prepared. By changing the foaming conditions, the effect of resin concentration, foaming pressure, foaming temperature, and curing agent content on the foaming behavior and the structure of carbon foams are studied. The results show that as the resin concentration increases, the pore size of the foamed carbon becomes smaller and the distribution becomes more uniform;the optimal amount of curing agent(hexamethylenetetramine) is 10%. The pore structure exhibits regular changes with the increase of foaming pressure, and the reasonable foaming pressure range is 1.5~2.0 MPa. Following the nucleation foaming mechanism, the foaming temperature zone can be in the range of 170~190 ℃ to prepare intact and difficultto-crack foamed carbon.