results from 29 si nmr analysis are reported in the following table based on these results it was found that no silanol group had been produced by secondary reactions and that the desired carbinol containing polydimethylsiloxane vi with the following structure had been obtained str8 ______________________________________results of sup 29 si nmr analysis for polysiloxane vi structure molar ratio ______________________________________ 8 3 str9 91 7 str10 0______________________________________ was introduced into a 1 000 ml four neck flask equipped with a stirrer thermometer reflux condenser and addition funnel the temperature was gradually raised to 50 degrees centigrade and 1 1 parts of a 1 weight solution of chloroplatinic acid in tetrahydrofuran was introduced 373 parts polydimethylsiloxane with the average structural formula and containing 0 3013 weight silicon bonded hydrogen was added dropwise from the addition funnel over 30 minutes the temperature in the flask had risen to 110 degrees centigrade at the completion of addition due to the exothermic reaction the temperature was then raised to 120 degrees centigrade and a reaction was carried out at this temperature for 2 hours samples were taken and the low boilers were distilled off in vacuo when it could be confirmed that the absorption characteristic of sih was no longer present in the infrared absorption spectrum the product.