Commonwealth Scientific and Industrial Research Organisation

Other

David Geoffrey Hawthorne

Jonathan Howard Hodgkin

David Henry Solomon

Jean Drummond Swift

Bryan Clarence Loft

Bronwyn Glenice Laycock

Trevor C Morton

The invention provides a method for promoting the curing reactions of an acetylenic oligomer or polymer, characterized in that the oligomer or polymer is cured in the presence of sulfur or an organic sulfur derivative which is capable of lowering the temperature of cure of the oligomer or polymer. The invention also provides a process for producing a polyimide oligomer or polymer containing an aliphatic or aromatic disulfide moiety which is covalently bound to, and forms an integral part of the oligomer or polymer and which is capable of lowering the temperature of cure of the oligomer or polymer, characterised in that a suitable amount of a diamino-disulfide or dianhydride-disulfide, or any suitable derivative or precursor thereof, is introduced into the mixture of aromatic diamines, tetracarboxylic dianhydrides, and the phenylethynyl-substituted amine or anhydride normally used for the reparation of the oligo-imide.

Reduced temperature curing of acetylenic polymers

A process for the preparation of an oligomeric polyimide comprises: mixing a tetracarboxylic acid, a dianhydride, a partially hydrolysed dianhydride or a mixture thereof with a diamine in a reaction medium comprising greater than 80% by weight water, and heating mixture in said reaction medium at a temperature above 100&deg; C. for a time sufficient to form said oligomeric polyimide.

Aqueous polyimide process

Oligomers are produced from unsaturated monomers. They contain terminal unsaturation and have a degree of polymerization of from 2 to 200. These oligomers are produced by the free radical polymerization of unsaturated monomers using as an initiator and/or chain transfer agent in the process a transition metal complex comprising a metal cation and at least one chelating agent, said transition metal complex being generally in accordance with formula (I), wherein M is a transition metal ion which can form hexa- or penta-coordinated structures and, when complexed in this manner, has two or more readily interconverted adjacent valence states, R is hydrogen or an organic group or a transition metal complex derived form formula (I) and L is a ligand or controlling the stability and electron transfer properties of the transition metal complex and consists of an electron pair donor (Lewis base) capable of coordination with the metal ion.

Oligomerization process

A method of modifying the surface properties of particulate mineral materials by forming on the surface of the particles a coating having a significant number of acidic sites with pKa values of less than 2.8.

Modification of mineral surfaces

A method of modifying the surface properties of titanium dioxide pigments and fillers by forming on the particles a surface coating of an aluminium compound, the coating having a significant number of acidic sites with pKa values of less than 2.8.

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South Oakleigh, Australia

David Geoffrey Hawthorne