Abstract
The curing behavior of a novolac resin (NV) cured with hexamethylenetetramine (HMTA), as well as the influence of an excess amount of HMTA on the curing reaction, were investigated by dynamic light scattering and gel permeation chromatography. A two-roll mixing mill process was applied to control the curing reaction degree. The dependence of the number of mixing times on the weight-average molecular weight (Mw) and hydrodynamic radius (Rh) of NV differed significantly with the HMTA amount. A larger quantity of HMTA resulted in faster growth and larger Rh and Mw values. The relationship between Mw and Rh for NV in tetrahydrofuran indicates two different polymer-growth mechanisms irrespective of the excess amount of HMTA (that is, power-law and subsequent deviation corresponding to the chain extension and intermolecular reactions between larger molecules, respectively). These results suggest that structural differences governing the mechanical properties of phenolic resins are initiated in the pregel stage, followed by noticeable differences in the mechanical properties during the subsequent curing process.
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References
Baekeland, L. H . Method of making insoluble products of phenol and formaldehyde, USA, Patent 942699 (1907).
Gardziella, A., Pilato, L. A. & Knop, A. Phenolic Resins: Chemistry, Applications, Standardization, Safety and Ecology 2nd edn (Springer, Berlin, Germany, 1999).
Pilato, L. Phenolic Resins: A Century of Progress, (Springer, Berlin, Germany, 2010).
Pascault, J. P., Sautereau, H., Verdu, J. & Williams, R. J. J. Thermosetting Polymers, (Marcel Dekker, New York, NY, USA, 2002).
Drumm, M. F. & Leblanc, J. R. Step Growth Polymerizations Vol. 3 (ed. Solomon, D. H.) Ch. 5, 157–278 (Marcel Dekker, New York, NY, USA, 1972).
Borrajo, J., Aranguren, M. I. & Williams, R. J. J. Statistical aspects for the production of novolacs. Polymer 23, 263–266 (1982).
Stockmayer, W.H. Theory of Molecular Size Distribution and Gel Formation in Branched-Chain Polymers. J. Chem. Phys. 11, 45–55 (1943).
Carotenuto, G. & Nicolais, L. Kinetic study of phenolic resin cure by IR spectroscopy. J. Appl. Polym. Sci. 74, 2703–2715 (1999).
Zhang, X., Looney, M. G., Solomon, D. H. & Whittaker, A. K. The chemistry of novolac resins: 3. 13C and 15N n.m.r. studies of curing with hexamethylenetetramine. Polymer 38, 5835–5848 (1997).
Sojka, S. A., Wolfe, R. A. & Guenther, G. D. Formation of phenolic resins: mechanism and time dependence of the reaction of phenol and hexamethylenetetramine as studied by carbon-13 nuclear magnetic resonance and fourier transform infrared spectroscopy. Macromolecules 14, 1539–1543 (1981).
Nomoto, M., Fujikawa, Y., Komoto, T. & Yamanobe, T. Structure and curing mechanism of high-ortho and random novolac resins as studied by NMR. J. Mol. Struct. 976, 419–426 (2010).
de Medeiros, E. S., Agnelli, J. A. M., Joseph, K., de Carvalho, L. H. & Mattoso, L. H. C. Curing behavior of a novolac-type phenolic resin analyzed by differential scanning calorimetry. J. Appl. Polym. Sci. 90, 1678–1682 (2003).
Dominguez, J. C., Alonso, M. V., Oliet, M., Rojo, E. & Rodriguez, F. Kinetic study of a phenolic-novolac resin curing process by rheological and DSC analysis. Thermochim. Acta 498, 39–44 (2010).
Markovic, S., Dunjic, B., Zlatanic, A. & Djonlagic, J. Dynamic mechanical analysis study of the curing of phenol-formaldehyde novolac resins. J. Appl. Polym. Sci. 81, 1902–1913 (2001).
Izumi, A., Nakao, T. & Shibayama, M. Atomistic molecular dynamics study of cross-linked phenolic resins. Soft Matter 8, 5283–5293 (2012).
Izumi, A., Takeuchi, T., Nakao, T. & Shibayama, M. Dynamic light scattering and small-angle neutron scattering studies on phenolic resin solutions. Polymer 52, 4355–4361 (2011).
Izumi, A., Nakao, T. & Shibayama, M. Synthesis and properties of a deuterated phenolic resin. J. Polym. Sci. A Polym. Chem. 49, 4941–4947 (2011).
Izumi, A., Nakao, T., Iwase, H. & Shibayama, M. Structural analysis of cured phenolic resins using complementary small-angle neutron and X-ray scattering and scanning electron microscopy. Soft Matter 8, 8438–8445 (2012).
Izumi, A., Nakao, T. & Shibayama, M. Gelation and cross-link inhomogeneity of phenolic resins studied by 13C-NMR spectroscopy and small-angle X-ray scattering. Soft Matter 9, 4188–4197 (2013).
Izumi, A., Nakao, T. & Shibayama, M. Gelation and cross-link inhomogeneity of phenolic resins studied by small- and wide-angle X-ray scattering and 1H-pulse NMR spectroscopy. Polymer 59, 226–233 (2015).
Shibayama, M. Spatial inhomogeneity and dynamic fluctuations of polymer gels. Macromol. Chem. Phys. 199, 1–30 (1998).
Shibayama, M. & Norisuye, T. Gel formation analyses by dynamic light scattering. Bull. Chem. Soc. Jpn 75, 641–659 (2002).
Shibayama, M., Ozeki, S. & Norisuye, T. Real-time dynamic light scattering on gelation and vitrification. Polymer 46, 2381–2388 (2005).
Shibayama, M., Karino, T. & Okabe, S. Distribution analyses of multi-modal dynamic light scattering data. Polymer 47, 6446–6456 (2006).
Chen, W., Wu, J. & Jiang, M. Phase separation in hexamethylenetetramine cross-linked Novolac/poly(ethylene-co-vinyl acetate) blends. Polymer 39, 2867–2874 (1998).
Yoonessi, M., Toghiani, H., Wheeler, R., Porcar, L., Kline, S. & Pittman, C. U. Jr . Neutron scattering, electron microscopy and dynamic mechanical studies of carbon nanofiber/phenolic resin composites. Carbon 46, 577–588 (2008).
Nomoto, M., Yamagishi, T. & Nakamoto, Y. Determination of branch density for high-ortho novolac and random novolac using 13C-NMR. J. Network Polym. Jpn 27, 210–217 (2006).
Provencher, S. W. A constrained regularization method for inverting data represented by linear algebraic or integral equations. Comput. Phys. Commun. 27, 213–227 (1982).
Yaws, C. L. Handbook of Viscosity, (Gulf Professional Publishing, Houston, TX, USA, 1995).
Wohlfarth, C. & Wohlfarth, B. Optical Constants: Subvolume B: Refractive Indices of Organic Liquids (ed. Lechner M. D.) (Springer, Berlin, Germany, 1996).
Yamagishi, T., Nakatogawa, T., Ikuji, M., Nakamoto, Y. & Ishida, S. Computational study of network formation of phenolic resins. Angew. Makromol. Chem. 240, 181–186 (1996).
Yamagishi, T., Nakamoto, Y. & Ishida, S. Gelation reaction of phenolic resins. Kobunshi Kako Jpn. 34, 178–183 (1999).
Yarovsky, I. & Evans, E. Computer simulation of structure and properties of crosslinked polymers: application to epoxy resins. Polymer 43, 963–969 (2002).
Nakao, T., Tanaka, F. & Kohjiya, S. Cascade theory of substitution effects in nonequilibrium polycondensation systems. Macromolecules 35, 5649–5656 (2002).
Nakao, T., Tanaka, F. & Kohjiya, S. New cascade theory of branched polymers and its application to size exclusion chromatography. Macromolecules 39, 6643–6652 (2006).
Aranguren, M. I., Borrajo, J. & Williams, R. J. J. Statistics of novolacs. Ind. Eng. Chem. Prod. Res. Dev. 23, 370–374 (1984).
Katovic, Z. & Stefanic, M. Intermolecular hydrogen bonding in novolacs. Ind. Eng. Chem. Prod. Res. Dev. 2, 179–185 (1985).
Looney, M. G. & Solomon, D. H. The chemistry of novolac resins. I. A review on the use of models. Aust. J. Chem. 48, 323–331 (1995).
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Shudo, Y., Izumi, A., Takeuchi, T. et al. Dynamic light scattering study of the curing mechanisms of novolac-type phenolic resins. Polym J 47, 428–433 (2015). https://doi.org/10.1038/pj.2015.15
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DOI: https://doi.org/10.1038/pj.2015.15
