Synthesis of a Formyl Group-Containing Reactive Novolac

Abstract

We report the preparation of a new novolac having formyl groups by the addition-condensation of 2,4,6-trimethoxy-benzaldehyde (1) and 1,3,5-trimethoxybenzene (2) with formaldehyde. In the case of the polymerization of 1 and formaldehyde, polymerization did not occur; however, the polymerization of 1, 2 and formaldehyde proceeded to give polymer 3 (Mn 4200, Mw/Mn 1.2). The FT-IR, 1H NMR and 13C NMR spectra of 3 showed that it had phenylene-methylene units on the polymer backbone and the formyl groups of 1 remained without side reactions. To evaluate its ability as a reactive polymer, the imination of 3 with 1,5-diaminopentane was carried out to obtain an organo-insoluble gel (5), which had the network structure of 3 and a pentamethylene unit via the imine moiety. The temperature at 5% loss in weight (Td5, 335 °C) of 5 slightly decreased compared to that of 3 (351 °C). This result indicates that polymer 3 can be utilized as a reactive polymer, and form a thermostable gel via the imine moiety.