| 摘要 |
Polymerisation in suspended emulsion of the corresponding monomer(s). <??>An aqueous solution of at least a part of an initiating system is dispersed, in finely divided form, in a monomeric or comonomeric composition of vinyl type and the polymerisation of the said composition is carried out. The quantity of water in the said aqueous solution represents at least 19 % and preferably at least 20 % by weight relative to the said monomeric or comonomeric composition. <??>In the case of the polymerisation of a monomeric or comonomeric composition based on vinyl chloride the said process makes it possible to obtain, with a degree of conversion of the monomeric or comonomeric composition which is higher than 50 % and which may exceed 65 %, polymers and copolymers made up of particles with a mean diameter greater than 10 mu m exhibiting both an apparent density which can exceed 0.55 g/cm<3> and a porosity, evaluated by a plasticiser uptake value at room temperature, which can exceed 30 g of di(2-ethylhexyl) phthalate per 100 g of resin. |
