磷酸改性酚醛树脂的结构与耐热性能

Structure and Thermal Resistance of Phosphoric Acid-modified Phenol-formaldehyde Resin

通过用磷酸对酚醛树脂进行改性,得到一种改性酚醛树脂。采用红外光谱、差热分析和热重分析等技术对酚醛树脂改性前后的结构和耐热性进行考察,并通过测试试样的拉伸剪切强度和抗压强度对改性酚醛树脂的力学性能进行评价。结果表明:经磷酸改性后,在酚醛树脂分子中引入了键能较高的P—O—C和P=O键,使酚醛树脂形成了热稳定性较高的杂环结构并提高了树脂的芳香性,降低了树脂在高温下的分解量,从而使其耐热性和力学性能得到改善。

A new phenol-formaldehyde resin was prepared by modification of phenol-formaldehyde res- in with phosphoric acid. The structure and thermal resistance of the phenol-formaldehyde resin before and after modification were investigated by Fourier transform infrared spectroscopy, differential scan- ning calorimetry, and thermogravimetric analysis. Meanwhile, the mechanical property of the modi- fied resin was evaluated by measuring the tensile shear strength and compressive strength. Results show that new bonds of P--O--C and P= 0 with higher bond energy are introduced into phenol-form- aldehyde molecules after modified by phosphoric acid. As compared with the unmodified phenol-form aldehyde, the heterocyclic structure with higher thermal stability forms and the aromaticity increases in modified phenol-formaldehyde molecules. Consequently, the low decomposition at elevated temper- ature is resulted. As a result, the thermal resistance and mechanical properties of the phenol-formal- dehyde resin are improved markedly.