Patent GB-1479475-A (GB)
Title: High temperature carborane-siloxane elastomers intermediate polymeric products and process for preparation
IPC: C08G77/48
Filed: 1974-07-23
Abstract: 1479475 Carborane - siloxane elastomers UNION CARBIDE CORP 23 July 1974 [24 July 1973] 32500/74 Heading C3T A process for the preparation of an essentially linear carborane-siloxane polymer having the following unit formula comprises (a) contacting a carborane disilanol of the formula with an organosilicon compound selected from (i) silylamines or α,#-diaminosiloxanes of the formula (ii) ureido-silanes or α,#-ureidosiloxanes of the formula or (iii) silyl carbamates or α, #-carbamoyl siloxanes of the formula wherein R<SP>1</SP> and R<SP>2</SP> represent hydrogen, or groups containing up to 14 carbon atoms selected from alkyl, alkoxy, alkenyl, cycloalkyl, aryl, alkaryl, aralkyl, alkoxyaryl, haloalkyl, haloaryl, cyanoalkyl, morpholinyl and pyridinyl; and R<SP>3</SP> represents hydrogen or a group containing up to 14 carbon atoms selected from alkyl, alkenyl, cycloalkyl, aryl, alkaryl, aralkyl, alkoxyaryl, haloaryl, cyanoalkyl, morpholinyl and pyridinyl, and wherein 2 R<SP>3</SP>s can when taken together contain up to 6 carbon atoms and represent alkylene, dialkylene amine or alkyl-substituted dialkylene amine; and R<SP>4</SP> and R<SP>5</SP> represent hydrogen or groups containing up to 14 carbon atoms selected from alkyl, alkoxy, alkenyl, aryl, alkaryl, aralkyl, alkoxyaryl, haloalkyl and haloaryl; and X represents a divalent radical derived from 1,7-decacarborane, 1,12 - decacarborane, 1,10 - octacarborane, 1,6 - octacarborane, 2,4 - pentacarborane, 1,6 - tetracarborane, 9 - alkyl - 1,7- decacarborane, 9,10-dialkyl-1,7 -decacarborane, 2 - alkyl - 1,12 - decacarborane, 2 - alkyl - 1,10- octacarborane, 8 - alkyl - 1,6 - octacarborane, decachloro - 1,7 - decacarborane, decachloro- 1,12 - decacarborane, octachloro - 1,10 - octacarborane, decafluoro - 1,7 - decarborane, decafluoro - 1,12 - decacarborane, octafluoro- 1,10 - octacarborane or mixtures thereof; m and n are each 0-4; and (b) recovering the polymer. In general the polymers have M. Wts. up to 150,000 or higher. The invention also relates to the preparation of end functionalized oligomers which are intermediate in the formation of the above polymers and which contain silanol, silyl amine, silyl urea or silyl carbamate end groups and having less than 100 repeating units comprising (a) contacting the above carborane disilanol with at least one of the above organo-silicon compounds (i)-(iii) in an amount which is either greater than or less than the number of moles of said carborane disilanol, and (b) recovering the oligomer. Crosslinked elastomers can be produced from the polymers by heating a composition comprising the polymer and optionally a filler and a curing agent, e.g. an organic peroxide. Suitable fillers are carbon black, pyrogenic silica, precipitated silica, fumed silica, silica gel, diatomaceous earth, clay, calcium carbonate, titanium dioxide, iron oxide, zinc oxide, quartz and aluminium oxide. In examples 3-7 carborane siloxane polymers are prepared from bis(N,N-dimethylamino)- dimethylsilane (II) and bis(hydroxydimethylsilyl) meta-carborane (I) by any one of the following processes: (i) neat polymerization by heating in the absence of a solvent; (ii) solution polymerization by heating to reflux in toluene; (iii) by sequential addition of the silyldiamine (II) to the carborane disilanol (I) and viceversa and heating to reflux in toluene; (iv) by the low-temperature addition of the carborane disilanol (I) to the silyldiamine (II) in chlorobenzene and subsequent hydrolysis, each process being carried out in a nitrogen atmosphere. In Examples 8-12 polymers are prepared from silydiamine (II) and a mixture of m-carborane disilanol (I) and the corresponding p-carborane disilanol in any one of the following percentage ratio: 50/50; 15/85; 70/30; 0/100; or 93/7 in an organic solvent either by reacting first at or below ambient temperatures and then by heating under reflux or in the latter case by heating to reflux as soon as the stoichiometric amounts of the components have been added. In Example 17 a polymer is prepared from a silyl urea, prepared from silyl diamine (II) and phenyl isocyanate, and m-carborane disilanol (I). In Example 18 polymers are prepared from bis(N,- N<SP>1</SP>-dimethyl carbamoyl) dimethyl silane and m-carborane disilanol (I) by (i) solution polymerization in chlorobenzene or heptane first at room temperature then under reflux, or (ii) by low temperature vacuum polymerization in chlorobenzene, or (iii) by neat polymerization at 40‹ C. In Example 19 a polymer is prepared from m-carborane disilanol (I) and by reaction at room temperature. Uses.-Seals; gaskets; extrusions, e.g. wire coatings.