| 摘要 |
<p>The process comprises: (a) the introduction, into a reactor, [lacuna] a reaction mixture comprising all the water, acrylonitrile, initiator or initiators, chain-transfer agent or agents and suspending agent or agents and optionally a predetermined fraction of the total amount of the styrene; (b) stirring the reaction mixture and increasing the temperature of this reaction mixture to 60 °C and then to 120 °C; (c) when the temperature of the reaction mixture has reached 60 °C or 120 °C, the addition of the remaining amount of styrene, so as to keep constant the styrene monomer/acrylonitrile monomer ratio in the reaction mixture throughout the duration of the addition; (d) raising the temperature of the reaction mixture to 140 °C and the maintenance at this temperature for a sufficient duration to bring the copolymerization to completion; and (e) cooling the reaction mixture and the recovery of the styrene/acrylonitrile copolymer. Application to the manufacture of SAN copolymers having a level of acrylonitrile of at least 40 % by weight.</p> |
