Patent ID: 7365135

Claim:
A method for preparing a novolac phenolic resin/silica organic-inorganic nanocomposite, which comprises the following steps: a) grafting a glycidyl alkylene trialkoxy silane having a formula (I) to a novolac phenolic resin in an organic solvent to form a modified novolac phenolic resin of formula (II), wherein hydroxy groups of said novolac phenolic resin and epoxy groups of said glycidyl alkylene trialkoxy silane undergo a ring opening reaction: wherein R 1 is C 1 -C 4 alkyl, and n is an integer of 1-6; wherein R 1 and n are defined as above; b) mixing a tetralkoxy silane, Si(OR 2 ) 4 , wherein R 2 is C 1 -C 4 alkyl, an acid and water with the modified novolac phenolic resin in Step a), such that alkoxy groups of said tetralkoxy silane and the alkoxy groups of said modified novolac phenolic resin are hydrolyzed into hydroxy groups, and undergo a condensation reaction to form a —Si—O—Si— bonding; c) adding a curing agent for novolac phenolic resin to the resulting reaction mixture from Step b); d) removing the organic solvent and water from the mixture resulting from Step c) by evaporation; and e) heating the resulting mixture from Step d) so that a portion of the novolac phenolic resin in the condensation production of Step b) is cross-linked to form a novolac phenolic resin/silica hybrid organic-inorganic nanocomposite.