Study On Highly Efficient AlCl₃/Oxygen-Containing Initiator For Synthesis Of MMPIB And HMPIB

Medium and high molecular weight Polyisobutylene,which is colorless,tasteless and non-toxic material,is widely used with excellent chemical stability,good air tightness and electrical insulation.Especially,high molecular weight polyisobutylene,as high value-added material,could be used for anti-corrosion containers,cables insulation materials and other areas.But it is monopolized by the foreign enterprises due to the specific process and other reasons.Therefore,it is of great significance and application value to develop a new and efficient catalyst system of high molecular weight polyisobutylene.Based on the polymerization of isobutylene catalyzed by AlCl3/oxygen-containing initiator system,this paper concerns the influence of complexes between different types of initiator and AlCl3 on the cationic polymerization of isobutylene,and studies the synthesis of medium and high molecular weight polyisobutylene(PIB)by using AlCl3/phenetole system and AlCl3/phenetole·TiCl4/H2O system.It was on research conclusions of the effects of catalyst concentration,polymerization temperature,monomer concentration,solvent polarity and polymerization time on the polymerization process,conversion of monomer,the molecular weight and the molecular weight distribution of the polymerization products.The results show that:? To a certain extent,different types of oxygen-containing initiators complex with AlCl3 could induce the polymerization of isobutylene,and AlCl3/phenetole system showed the highest polymerization activity in the process of preparation of polyisobutylene than others,in which the conversion was up to 99%,the average molecular weight of the product was 22.15×104(g/mol)and the PDI was 3.08.?While AlCl3/phenetole was used as the initiating system,the molecular weight of the polyisobutylene was up to 48.56×104(g/mol)at the polymerization temperature of-60? by using hexane/dichloromethane(v:v=50:50)as solvent.? It also found that AlCl3/phenetole TiCl4/H2O system show higher reactivity then AlCl3/phenetole initiation system in the preparation of polyisobutylene,the monomer conversion of polymerization by using the double-center catalytic system is much larger than that using AlCl3/phenetole system with the same catalyst concentration.And the monomer conversion of the double-center catalyst system is more sensitive to the change of the catalyst concentration.?With temperature decreased,the rate of chain transfer became slower,which can effectively increase the molecular weight of the polyisobutylene but decrease the catalyst activity.