高强度酚醛树脂泡沫炭的制备研究

Preparation of Carbon Foams with High Compressive Strength Derived from Phenolic Resin

以自制甲阶酚醛树脂为原料,通过发泡法制备泡沫炭,考察了发泡和炭化条件对泡沫炭的微观结构、物相组成、机械强度的影响。结果表明:酚醛树脂泡沫在200~650℃之间应采用较慢的升温速率(1℃/min)进行炭化;由XRD分析发现,900℃炭化温度下所得泡沫炭主要以无定形炭形式存在,同时还存在NaCl晶体;SEM分析可知,表面活性剂吐温-80用量主要影响泡沫炭中泡孔的分布均匀性,发泡剂正己烷用量对泡沫炭的泡孔数量及孔径影响较大,而固化剂盐酸用量则对泡孔的孔径影响较大。泡沫炭制备的较佳工艺为:固化剂用量、表面活性剂和发泡剂用量分别为甲阶树脂质量的3%、6%和6%,此条件下所得泡沫炭的泡孔孔径为50~150μm,孔泡结构规整、孔壁较薄,其表观密度为0.276 g/cm^3,比表面积为137.9 m^2/g,抗压强度为11.1 MPa。

Carbon foams were synthesized by foaming method with self-made phenolic resin as precursor. The effects of the foaming conditions and carbonization conditions on microstructure,phase composition and mechanical properties of carbon foams were investigated. The results showed that phenolic resin foams should be heated in a low heating rate（ 1 ℃/min） at 200- 650 ℃during carbonization process. Carbon foams obtained under carbonization temperature 900 ℃ were mainly amorphous carbon and sodium chloride crystal,which were proved by XRD analysis. The SEM images revealed that the surfactant（ Tween 80） had a significant influence on the distribution of bubbles in carbon foams,and the amounts of foaming agent（ n-hexane） mainly affected the number of bubbles and pore size,while the amounts of curing agent（ hydrochloric acid） influenced the pore size significantly.The optimum preparation conditions of carbon foams were curing agent 3%,surfactant 6% and foaming agent 6%（ based on phenolic resin weight）,respectively. The resultant carbon foam had pore size ranged of 50- 150 μm with uniform structure and the thinner hole-wall. It also had a apparent density of 0. 276 g/cm^3,specific surface area of 137. 9 m^2/g,and the compressive strength of 11. 1 MPa.