Copolymerizations of alkyl acrylates (alkyl: ethyl, butyl, isobutyl, tert-butyl, and 2-ethylhexyl) with vinyl chloride and isobutylene in the presence of catalytic amounts of C,H,AICl, were studied. Depending on the monomer feed, equimolar or acrylate-rich copolymers were obtained in most of these reactions. Only tert-butyl acrylate does not produce any copolymer, due to its decomposition under the action of C,H,AIC12. 2-Ethylhexyl acrylate forms with isobutylene only acrylate-rich copolymers. By I3C NMR spectroscopy it could be shown that equimolar copolymers have an alternation structure. t MtX.
The copolymerization of methyl acrylate (MA) and isobutylene (IB) in the presence of Lewis acids (EtAICI,, Et,AICI. Et3AI, AICI,, and ZnCI,) a t low Lewis acid/MA mole ratio was investigated. EtAICI, and Et,AICI were found to initiate the spontaneous reaction. An alternating copolymer was produced in this reaction when an excess of IB in the initial monomer feed was used. The copolymerization in the presence of Et,AI, AICI,, and ZnCI, did not proceed spontaneously and was initiated by dibenzoyl peroxide (BPO). In this case MA-rich copolymers are formed even in systems containing a large excess of IB in the monomer feed. The addition of BPO to systems containing ethylaluminium chlorides strongly diminishes the tendency towards alternating propagation. It was concluded that the mode of initiation has a significant influence on the copolymer composition. The alternating copolymerization by EtAIClz was studied in detail in order to determine the influence of the catalyst concentration, monomer feed ratio, reaction temperature and time on the monomer conversion, copolymer composition, molecular weight and tacticity. 0025-1 16X/82/05
SynopsisPolymerization of vinyl chloride in the presence of systems containing a transition metal compound/Lewis base and an organoaluminum compound of a different length of carbon chain have been carried out. The influence of the structure and the concentrations of particular components on the polymerization yield and molecular weight of the products has been determined. The polymerization of vinyl chloride proceeds according to the free radical mechanism, and the effectiveness of such types of initiators decreases with an increase in the length of the substituent chain in the organoaluminum chain. When using ethyl derivatives, the maximum degree of vinyl chloride conversion is about 75%, and for polystyryl or polyisoprenylaluminum of an average polymerization degree of 50-100, the conversion did not exceed 0.5%. The maximum polymerization degree of vinyl chloride in block copolymers containing polyisoprenyl or polystyryl units was 90-300.
The copolymerization of vinyl chloride (VC) and methyl acrylate (MA) in the presence of ethylaluminium compounds (C2H5AlCl2, (C2H5)2AlCl, and (C2H5)3Al) at low ethylaluminium compound (EAC)/MA mole ratios was investigated. An alternating copolymer was produced in this reaction when an excess of VC in the initial monomer feed was used. The addition of dibenzoyl peroxide (BPO) to the systems containing EAC resulted in an increase of the alternating copolymer yield. In polymerization systems containing EAC resulted in an increase of the alternating copolymer yield. In polymerization systems containing EAC combined with VOCl3 an enhancement of the alternating copolymer yield and formation of VC‐rich copolymers were observed. In the polymerization system with (C2H5)3AlVOCl3 a VC‐rich copolymer was the main product. It was concluded that VC‐rich copolymers are formed in the random radical copolymerization which occurs when most of EAC is complexed by the alternating copolymer chain. The structure of alternating and VC‐rich copolymers was studied in detail by means of 13C NMR spectroscopy.
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