NOVEL POLY(VINYL ETHER) BLOCK-COPOLYMERS - SYNTHESIS AND COLLOIDAL STABILIZATION OF ALPHA-FE2O3 IN WATER AND ORGANIC-SOLVENTS

Novel poly(vinylmethylether)-b-poly(vinyloxy-4-butyric acid) diblock c opolymers were made for the purpose of colloidal stabilization of part icles in liquids. The synthesis via cationic polymerization with HI/I- 2 initiation and the characterization of such novel diblock copolymers is described. A set of polymers was prepared including block copolyme rs with different block length ratios and the two separate homopolymer s having the chemical composition of one of the blocks. Colloidal stab ilization of alpha-Fe2O3 particles in water could be realized with all polymers except with the poly(vinylmethylether) homopolymer. One of t he block copolymers was used for evaluation of the stabilizing abiliti es in organic solvents. Stable alpha-Fe2O3 dispersions could be prepar ed in solvents with very different polarities, ranging from methanol t o toluene. In addition, it is shown that particles stabilized with the se block copolymers can be easily transferred from water to an organic liquid.