含氮试剂对p-DCC/AlCl_3引发异丁烯正离子聚合的影响  

THE EFFECTS OF NUCLEOPHILES CONTANING NITROGEN ON CATIONIC POLYMERIZATION OF ISOBUTYLENE INITITATED BY p-DCC/AlCl_3

作　　者：张蓓[1] 吴一弦[1] 李艳[1] 刘迅[1] 徐旭[1] 武冠英[1] 

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室,北京100029

出　　处：《高分子学报》2007年第11期1040-1046,共7页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20474006);教育部亲世纪优秀人才支持计划(项目号NCET-04-0124);北京市教委共建资助项目

摘　　要：以对-二枯基氯(DCC)/AlCl3体系引发异丁烯在二氯甲烷(CH2Cl2)正己烷(Hex)(40/60,V/V)混合溶剂中进行正离子聚合,探讨了DCC用量、含氮试剂2,6-二叔丁基吡啶(DtBP)和三苯胺(TPA)对异丁烯正离子聚合转化率、产物分子量及其分布的影响.结果表明,DCC和体系中微量水均可与AlCl3产生竞争络合,形成两种活性中心并引起相继的竞争引发,聚合产物的GPC谱图呈双峰分布,分子量分布宽;增加DCC用量有利于DCC与AlCl3的络合,致使链增长反应主要通过DCC与AlCl3络合形成的活性中心引发,但聚合产物分子量相对较低,分子量分布较宽;使用DtBP,可有效地抑制微量水引发及活性链向单体的转移反应,使分子量分布明显变窄,基本实现DCC的控制引发;采用DtBP与TPA共同调节聚合反应,可使聚合产物分子量分布变窄的同时,进一步提高分子量,从而得到相对较高分子量(Mw=103200)和单峰分子量分布(Mw/Mn=2.09)的聚异丁烯产物.The cationic polymerization of isobutylene （ （DCC） in conjunction with coinitiator A1C13 was carried IB） by utilizing difunctional initiator p-dicumyl chloride out in CH2C12/Hex （40/60, V/V） solvent mixtures. The effects of concentrations of 2, 6-di-tert-butylpyridine （DtBP）, triphenylamine （ TPA ） and A1C13 on monomer conversion, molecular weight and molecular weight distribution （MWD） of polyisobutylene （PIB） were investigated The small amount of water in the polymerization system in conjunction with A1C13 could induce a conventional uncontrolled rapid polymerization of IB and lead to polyisobutylene with broad molecular weight distribution （Mw/ Mn = 4.55）.It was found that the GPC trace of resultant polymers obtained by DCC/H20/A1C13 systems exhibited a bimodal distribution,which was attributed to the competition of initiation from two different active center, i. e., H^＋ A1C13 OH- （a） and A1C1^4- ^＋ C（ CH3 ）2 C6 H4 （ CH3 ）2 C ^＋ - A1C14 （b） even at high DCC concentrations. The initiation by active center （b） was increased whereas the molecular weight of the polymer decreased with a decrease in A1C13 concentration. The addition of proton trap D t BP in the monomer solution could obviously decrease or even suppress the initiation from active center （a） and the chain transfer reaction to monomer, leading to the polymers with unimodal molecular weight distribution. The initiation from active center （a） could be suppressed by introduction of TPA and DtBP even at low DCC concentrations. A desirable cationic polymerization of IB would be achieved with the DCC/A1C13 initiation system in the presence of TPA and D tBP, and the telechelic tert-Cl-polyisobutylene with relatively high molecular weight （Mw = 103200） and unimodal molecular weight distribution （Mw/Mn = 2.09） could be obtained.

关 键 词：正离子聚合 异丁烯 聚异丁烯 亲核试剂 

分 类 号：O631[理学—高分子化学]