THE PECULIARITIES OF PHYSICAL NETWORK FORMATION IN CARBOXYL-CONTAINING POLY(DIMETHYLCARBOSILOXANE)

An unusual effect of physical network formation during heating or at room temperature after previous heating was found for originally liquid poly-(dimethylcarbosiloxane) containing 0.5 - 2.5 mol% of side carboxyl groups by means of the measurement of its theological properties. The reason for this behaviour is supposed to be the predominance of intramolecular hydrogen bonding of COOH groups in original polymer and the intra- to intermolecular bonds rearrangement during heating. The alternative reason can be the microphase separation with domains of COOH groups. The reversibility of the network Is con,firmed by the decrease in the elasticity modulus,development of irreversible deformation on further heating and by break-up of junctions on the addition of small amounts of polar liquids.