Olefin Reduction Of Gasoline And Preparation Of Cross-linked Copolymer Microspheres Based On Self-stabilized Precipitation Polymerization

Unetherified gasoline refers to gasoline that has not been reduced olefins portion by etherification.That means unetherified gasoline olefins scale usually at a high level,which will lead to a series of problems such as deteriorating gasoline quality,damaging engine devices and furthermore causing air contaminations.However,the existing technologies relating to gasoline olefins reduction are generally not cost effective and very complicated.Our research group has developed a novel technique to reduce these negative components(olefins)in gasoline by self-stabilized precipitation polymerization(2SP).Through copolymerization with an active monomer such as maleic anhydride(MAH),the olefin components in this complex unetherified gasoline system can be directly and facilely converted into functional copolymers.However,this novel method still can be improved in cut down the olefin content more effectively.In addition,there are still some inevitable shortcomings of the resultant copolymers,the molecular weight are relatively low,and their glass transition temperature(Tg)are generally very high.In order to address the above-mentioned problems,we add four different functional monomers,including butyl acrylate(BA),acrylamide(AM),glycidyl methacrylate(GMA),and isoprene(IP)into the gasoline-MAH system.The olefin content in gasoline could be effectively reduced,and meanwhile copolymers of olefins,MAH and various functional monomers were successfully obtained.The specific research content in this paper are as follows:1.Through self-stabilized precipitation polymerization,the olefins in unetherified gasoline were directly copolymerized with MAH and functional monomer,leading to remarkable decrease in olefins content.The influences of functional monomer type,monomer concentration,monomer feed ratio,initiator type on olefins reduction efficiency,monomer conversion and polymerization yield were investigated in detail.The results of titration and elemental analysis show that the best olefins reduction efficiency can be achieved at proper monomer feed ratio.When olefin:MAH:BA=10:7.5:0.25,olefin:MAH:AM=10:7.5:0.25,olefin:MAH:GMA=10:7.5:0.25(Mass ratio,the same below),the olefins conversion rates are 44%,41%and 37%,respectively.2.The molecular weight,Tg,size and surface morphology of the asprepared poly(gasoline olefins/MAH/functionnal monomer)particles were characterized by means of GPC,DSC and SEM.The experimental results show that the functional monomer BA can significantly reduce Tg of the resultant polymer,and meanwhile leading to dramatic increase in molecular weight.Tg of the resultant terpolymer decreased from 166℃ to 136℃ when olefin:MAH:BA=10:5:2.5.In addition,the molecular weight increased obviously to 5600 when gasoline olefin:MAH:BA=10:5:0.5.3.Poly(gasoline olefin/MAH/IP)cross-linked copolymer microspheres were prepared by 2SP process.The effects of IP concentration(relative to the monomer mass)and monomer concentration on polymerization yield,morphology,particle size,particle size distribution and gel content of the asprepared polymer microspheres were investigated systematically.The experimental results show that when monomer feed ratio(olefin/MAH)is 10/6 under IP concentration of 3 wt%,the polymerization yield reached the highest value of 47%,and obtained the most regular spherical microspheres.The number average diameter of the microspheres is 892 nm,and the coefficient of variation is 3.29%.