By varying the -Si-O- chain lengths, side groups, and crosslinking, silicones can be synthesized with a wide variety of properties and compositions. Silicone polymers vary in consistencies ranging from gels to liquids to hard plastics and rubbers.4 The Si-O-B linkages that brought together polysiloxane chains are what gave the polymer its "bounce" and putty like consistency. .
Reactions: .
n (CH3)2SiCl2 (l) + n H2O (l) [(CH3)2SiO]n (l) + 2n HCl (g).
Experimental Method, Calculations, and Yield.
The materials needed for this experiment were a stir bar, hot plate and glassware (beakers, graduated cylinder and a round-bottom flask). The chemicals used in the experiment were diethyl ether, magnesium sulfate, sodium bicarbonate, boric acid and dimethyldichlorosilane. Dimethyldichlorosilane ((CH3)2SiCl2) is an irritant that causes burns and irritation to the eyes, skin, and respiratory system. Another hazard of this lab is that the dimethyldichlorosilane is readily hydrolyzed by moisture in the air to give HCl fumes, which are extremely dangerous, and as a result that part of the experiment must be done in the hood. Diethyl ether is extremely flammable and should be kept away from any open flames. In addition, magnesium sulfate and boric acid are irritants and contact with eyes and skin is hazardous. Based on the chemicals being used, gloves should be worn at all times when handling any chemicals and the experiment should be done in the hood in addition to the usual safety procedures, such as wearing goggles and a lab coat at all times. .
In the experiment diethyl ether and dimethyldichlorosilane were added in a 250mL round bottom flask. Water was then added in a drop wise fashion in order to hydrolyze the solution and this is when the HCl fumes were released. After the (CH3)2SiCl2 was hydrolyzed the solution was separated into its ethereal and aqueous layers in a separatory funnel. The aqueous solution can be discarded and then a dilute sodium bicarbonate solution should be prepared.