Process for making polymeric inorganic-organic compositions

A process for making an inorganic-organic interpenetrating network composition consisting essentially of an intimate combination of an inorganic gel component and an organic polymer component, said process comprising the following sequential steps:

• (1) intimately mixing together the following components A) through C) under such conditions that a homogenous liquid solution is initially formed:
• A) at least one inorganic gel precursor selected from the group of compounds consisting of
• tetraalkoxysilanes Si(OR.sup.1).sub.4, tetraalkyl titanates Ti(OR.sup.2).sub.4, tetraalkyl zirconates Zr(OR.sup.3).sub.4, chelated tetraalkyl titanates Ti.sup.a (OR.sup.4).sub.n X.sup.d.sub.p, and chelated tetraalkyl zirconates Zr.sup.a (OR.sup.5).sub.n X.sup.d.sub.p, wherein
• each one of R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 independently is a C.sub.1 -C.sub.6 alkyl;
• X is a chelating ligand;
• a is titanium and zirconium coordination number, being in each case an integer having a value of 4-6;
• d is a number, either 2 or 3, corresponding to the chelating ability of the ligand X, d being 2 for a bidentate ligand and 3 for a tridentate ligand;
• p is either 1 or 2, except that for d=3, p always is 1;
• and n=a-d.multidot.p;
• B) at least one organic polymer selected from the group consisting of modified cellulose derivatives, starch, polyamides, polyesters, polymethacrylates, polyacrylates, polyvinyl alcohol, copolymers of vinyl alcohol with ethylenically unsaturated monomers, polyvinyl acetate, poly(alkylene oxides), vinyl chloride homopolymers, vinyl chloride copolymers, terpolymers of ethylene with carbon monoxide along with an acrylic ester, terpolymers of ethylene with carbon monoxide along with vinyl monomer, polysiloxanes, polyfluoroalkylenes, poly(fluoroalkyl vinyl ethers), homopolymers of halodioxoles, copolymers of halodioxoles, homopolymers of substituted halodioxoles, copolymers of substituted halodioxoles, and poly(vinylpyrrolidone);
• and
• C) an organic carboxylic acid having a pK.sub.a value of at most 4.0, which organic acid may contain up to about 40 mole % water, and being selected from the group consisting of
• (i) acids miscible with components A) and
• (ii) acids miscible with liquids in which components A) are soluble,
• said acid being present in an amount of at least 2 moles per mole of all components A) present:
• the total amount of water present in the reaction medium being less than that of component C) and, further, such that the mole ratio of water to all components A) present is 0 to 20;
• (2) maintaining the above solution, with agitation as needed, at a temperature of about 0.degree.-100.degree. C. until gelation of the inorganic component occurs;
• and
• (3) recovering the resulting inorganic-organic interpenetrating network composition.