Synthesis of a Formyl Group-Containing Reactive Novolac

We report the preparation of a new novolac having formyl groups by the addition-condensation of 2,4,6-trimethoxybenzaldehyde (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 (M-n 4200, M-w/M-n 1.2). The FT-IR, H-1 NMR and C-13 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 (T-d5, 335 degrees C) of 5 slightly decreased compared to that of 3 (351 degrees C). This result indicates that polymer 3 can be utilized as a reactive polymer, and form a thermostable gel via the imine moiety.