Block Copolymers Based on Ethylene and Methacrylates Using a Combination of Catalytic Chain Transfer Polymerisation (CCTP) and Radical Polymerisation

Abstract

Twos calable polymerisation methods are used in combination for the synthesis of ethylene and methacrylate blockc opolymers. w-Unsaturated methacrylic oligomers (MMA n )produced by catalytic chain transfer (co)polymerisation (CCTP) of methyl methacrylate (MMA) and methacrylic acid (MAA) are used as reagents in the radical polymerisation of ethylene (E) in dimethyl carbonate solvent under relatively mild conditions (80 bar,7 0 8 8C). Kinetic measurements and analyses of the produced copolymers by sizee xclusion chromatography (SEC) and ac ombination of nuclear magnetic resonance (NMR) techniques indicate that MMA n is involved in adegradative chain transfer process resulting in the formation of (MMA) n -b-PE blockc opolymers.M olecular modelling performed by DFT supports the overall reactivity scheme and observed selectivities.T he effect of MMA n molar mass and composition is also studied. The blockc opolymers were characterised by differential scanning calorimetry (DSC) and their bulk behaviour studied by SAXS/WAXS analysis.

Synthesis of poly(methyl methacrylate)-b-polyethylene (PMMA-b-PE) block copolymers via conventional emulsion polymerization

“…Our previous study demonstrated that PMMA- b -PE copolymers can be formed by combining CCTP and radical polymerization of ethylene in DMC. 48 In that work, PMMA n oligomers obtained by CCTP were solubilized in DMC in the presence of AIBN. PMMA n chain-end double bonds were quickly consumed, and the molar mass of the PE block increased with the reaction time.…”

“…This might be showing rapid termination of growing polyethylenyl radicals with PMMA n and formation of PE homopolymer when all PMMA n has been consumed as previously observed in DMC. 48 After 4 h, an increase of both solids content and DP PE was observed for the two PMMA n (after 4 h: τ s,f = 7.4 wt% and DP PE = 26 and 16.6 wt% and 123 for PMMA 16 and PMMA 36 , respectively). This is indeed consistent with HT-SEC analyses (Fig.…”

“…A similar behavior was observed in our previous study conducted in DMC, in which the high molar mass population was assigned to the formation of PE homopolymer taking place when all the PMMA n chain transfer agents have been consumed. 48 However, under the conditions employed here, one might ask whether the consumption of the PMMA 16 unsaturated chain-ends is indeed only related to the reaction of polyethylenyl radicals formed in water (this is made possible by the solubility of ethylene in water from 0.3 g L −1 at 4.5 bars to 4.6 g L −1 at 110 bar at 75 °C 51 ) and entering the particles to react with PMMA 16 . An additional experiment was thus carried out under the exact same conditions but without ethylene pressure (run 2, Table 2) to further investigate this point.…”

“…42,46,47 We recently showed that PMMA produced by CCTP (PMMA n ) can serve as efficient degradative chain transfer agent in the radical polymerization of ethylene conducted in DMC under relatively mild conditions (80 bar and 70 °C). 48 Detailed characterizations of the obtained products combined with DFT calculations showed that the propagating polyethylenyl radicals produced upon initiation of ethylene polymerization rapidly react with the ω-chain end of the PMMA n to form an intermediate radical (Fig. 1).…”

Tailor-Made Functional Polyolefins of Complex Architectures: Recent Advances, Applications, and Prospects

“…These telechelic polymers could undergo further postpolymerization modification. Recently, D’Agosto et al synthesized block copolymers of ethylene and methyl methacrylate on the basis of CCTP and FRP ( M w up to 180 kg mol –1 ) . Nevertheless, chain shuttling polymerization (CSP) is a distinct CCTP technique best suited for synthesizing olefin block copolymers.…”