Carbocationic Polymerization In Presence Of Reactive Additives

The living cationic polymerization has been well developed since 1986[1], and now it has been shown to be a powerful technique to prepare PIB-based materials with unique properties[2~6]. One of the keys to a living cationic polymerization is to add some additives, including electron donor compounds, ammonium salts and chelating agents, into a reaction system. In recent years, almost all the living cationic polymerization systems to prepare the well-defined PIB contained the additives. All these additives, although with different mechanism, slow down the rate and suppress the side reaction of cationic polymerization. In our investigation, we chose and developed some compounds which have both a N, O-containing functional and a double bond polymerized via cationic method. We expected these compounds, as a reactive additive, play a dual role: converting the traditional cationic polymerization into the living one and being polymerized into the polymer. In the traditional polymerization systems, the added compound, having functional groups, is only used as an additive and it's useless when a polymerization is finished. But the reactive additive could be polymerized into the polymer. So even it is used in large amount, it won't be wasteful. Besides, the reactive additive can add the functional group into the polymer that can amplify the concept of living polymerization.In this thesis, four kinds of this additives were investigated, 5-Methyl-5-hexen-2-one(MHone), 5-hexen-2-one (5H2on), n-but-3-enyl butyl amine (CNC) and vinylbenzyl trimethylammonium chloride (vinN+Cl-). Firstly, we found that they all have positive effect on the cationic polymerization of IB and Styrene, such as narrowing the MWD and achieving the monomodal distribution. The living characteristics of this polymerization in the presence of the additives were checked by AMI ( all-monomer-in). It is found the polymerizations of IB in the presence of 5-Methyl-5-hexen-2-one, n-but-3-enyl butyl amine or vinylbenzyl trimethylammonium chloride are living. The 1H-NMR spectrum of PIB obtained in presence of n-but-3-enyl butyl amine or vinylbenzyl trimethylammonium chloride shows there are n-but-3-enyl butyl amine or vinylbenzyl trimethylammonium chloride unit in the polymer chain. These results indicated that these two compounds are a reactive additive which certainly plays a dual role: converting the traditional cationic polymerization of IB into the living one and being polymerized into the polymer. The mechanism of IB polymerization in the presence of vinylbenzyl trimethylammonium chloride was suggested.