Preparation and properties of poly( N-ethylmethacrylamide) networks

Abstract

The copolymerization kinetics of N-ethylmethacrylamide with methylene- bis-acrylamide are affected by the gel effect, as for most vinyl-divinyl systems. The concentration of crosslinks wasted in cycles at the gel point and determined from critical conversions is comparatively high, (60–90%) and increases with increasing concentration of the crosslinking agent and with dilution. The overall dependence of stress on time and elongation has been divided into deformational and time parts: the latter part decreases with increasing concentration of the crosslinking agent and decreasing concentration of the diluent, the equilibrium stress-strain dependences being described in terms of the kinetic theory of rubber elasticity. The interaction parameter Z of the system poly( N-ethylmethacrylamide)-water is linearly dependent on the volume fraction of polymer υ 2: Z = 0.48 + 0.319 υ 2 (25: υ 2<0.05 ; 0.22>). The effect of intermolecular interactions (entanglements) on the equilibrium mechanical behaviour disappears with increasing dilution. KCNS and Co(NO 3) 2 raise the swelling of gels in water while Mg(C1O 4) 2 has a pronounced salting-out effect, contrary to expectation.