Reaction of Lactone-Containing Poly(benzofuran-co-arylacetic acid) with Diamines to Cross-Linked Products of Improved Thermal Conductivity

The recently developed phenoplast-related polymer, poly(benzofuran-<i>co</i>-arylacetic acid), presents a versatile molecular structure containing lactone and carboxylic acid functionalities that offer significant flexibility in creating cured materials with tailored properties for diverse applications, wherein also the thermal conductivity is an important factor. This study analyses the possibility of forming amide moieties of poly(benzofuran-<i>co</i>-arylacetic acid) with diamines resulting in cross-linked products in order to control its thermal properties. The cross-linking process is achieved by utilizing three distinct diamines, 1,6-diaminohexane, <i>p</i>-xylylenediamine, and 4,7,10-trioxa-1,13-tridecanediamine, each possessing different degrees of polarity, flexibility, and reactivity. The resulting cross-linked zwitterionic poly(benzofuran-<i>co</i>-arylacetic acids) were structurally and morphologically characterized. By means of measuring the thermal conductivity and diffusivity of the materials, the possibility of adjusting the thermal properties of the cross-linked products by choosing appropriate linkers was determined. A case was developed where the thermal conductivity and diffusivity increased with temperature, a hardly found property in the cross-linking of polymers being important for many practical applications.