Synthesis and Properties of New Novolacs Based on Heteroatom-Bridged Phenol Derivatives

We describe the synthesis and properties of new novolacs prepared by addition-condensation of heteroatom-bridged phenol derivatives and formaldehyde. The trifluoroacetic acid-catalyzed polymerization of equimolar amounts of bis(4-methoxyphenyl) ether (1a) and formaldehyde proceeded homogeneously to afford the polymer (2a) in 49% yield (M-n 2600, M-w/M-u 1.8). From the FTIR, H-1-NMR, and C-13-NMR spectra of 2a, it was evident that the polymer had methylene moieties-bridged repeating units in the polymer backbone. A higher molecular weight novolac (2a') (yield 99%, M-n 16,600, M-w/M-n 12.9) could be prepared by using an excess of formaldehyde. Bis(4-methoxyphenyl) sulfone novolac (2b) (M-n 1300, M-w/M-n 1.2) and bis(4-methoxyphenyl) sulfide novolac (2d) (M-n 1200, M-w/M-n 1.9) were also prepared. However, the polymerization of bis(4-hydroxyphenyl) sulfone (1c) did not proceed, even when it was attempted under various reaction conditions. From TGA, the temperatures at 10% loss hi weight (T-10) for 2a, 2a', and 2b were found to be 413, 430 and 393 degrees C, respectively. These results suggested that heteroatom-bridged novolacs based on phenol derivatives have good thermal stability than other organosoluble polymers; moreover, these novolacs could be expected to function as processable materials, polymer blends for engineering plastics, etc. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 2719-2726, 2009