phase and an elastomeric phase in domains of nanometric size with an elastomer volume percentage of up to 15 preferably between 0 5 and 8 allowing for a considerable increase in the capacity to withstand acceptable deformation without breaking but since the separate elastomeric phase remains covalently bonded to the continuous matrix the potential decrease in young 39 s modulus values is significantly lower and a high percentage of the deformations produced in the u201c crush test u201d api 19c rp standard are recoverable fig4 and 5 show photographs of particles of the present invention of a diameter of around 0 45 mm after being subjected to a u201c crush test u201d api 19c rp standard at pressures of 10 000 and 12 000 psi 689 6 and 827 6 bar where the deformation produced by the force exerted by nearby particles can be clearly seen which does not consist of net spherical collapses but instead is partially recovered styrene solutions of copolymers of isoprene and styrene of butadiene and styrene and of isoprene butadiene and styrene were used in these copolymers both butadiene and isoprene contributed residual double bonds which reacted in the crosslinking process at different rates according to their electronic structure and steric hindrance copolymerized styrene reduced the magnitude of.