Synthesis of Poly(methyl methacrylate)‐Grafted Poly(ethylene‐co‐1‐octene) Copolymers by a “Grafting from” Melt Process

Abstract

Graft copolymers with a poly(ethylene‐co‐1‐octene) backbone and poly(methyl methacrylate) random polymer branches are successfully synthesized by the grafting‐from technique in the molten state. The in situ radical polymerization of methyl methacrylate from the polyolefin backbone is investigated with two different peroxide initiators at 135 and 150 °C, respectively. The number of PMMA grafts per polyolefin chain is varied from 0.08 to 1.07 with PMMA polymerization degrees of 500 and 18, respectively, depending on the experimental conditions. The effect of a nitroxyl‐based radical scavenger (i.e., DEPN) on competition between the grafting of PMMA from the polyolefin backbone and MMA homopolymerization is also explored.

Effect of nitroxyl-based radicals on the melt radical grafting of maleic anhydride onto polyethylene in presence of a peroxide

“…the reactions non-selective. As initiator, dialkyl peroxides are most commonly used and the decomposition mechanism involves initial O-O bond homolysis to generate the corresponding alkoxy radicals that can add to the grafting monomer, which would lead to homopolymers as undesired by-products [20][21][22][23][24]. Alkyl radicals formed by decomposition of the primary radicals are known to preferably add to the monomer.…”

Acyloxyimide derivatives as efficient promoters of polyolefin C–H functionalization: application in the melt grafting of maleic anhydride onto polyethylene

“…[18][19][20][21] These products are classically produced by the melt extrusion of the polyolefin and MA in presence of alkyl peroxides as radical initiators (Figure 1). 14,[22][23][24][25][26][27][28][29][30] This process creates reactive radical sites that may initiate the graft modification of polymers in presence of a vinyl monomer. The main drawback of the grafting by a radical pathway is the low selectivity of the alkoxyl radicals generated from the dissociation of peroxides, leading to side reactions such as coupling, chain scission and homopolymer formation.…”

Kinetic study on free radical grafting of polyethylene with acrylic acid by reactive extrusion

“…With increasing initiator and monomer concentrations, the grafting degree increased and the grating efficiency decreased. Radical scavenger was used to limit the formation of PMMA homopolymer …”

“…Radical scavenger was used to limit the formation of PMMA homopolymer. 21 Numerical simulations have been devoted to reactive extrusion processes for quantitatively analyzing the reaction trend and optimizing the processing conditions. [22][23][24][25][26] Such simulations have been performed by Motha and Seppala for the grafting of carboxylic acids and silanes to ethylene polymers, 27 Hojabr et al for the grafting of GMA onto PE, 28 Fukuoka for the grafting between PE and vinylsilane, 29 33 With accurate numerical models, evolutions of key variables such as monomer conversion, grafting degree and fluid viscosity can be quantitatively predicted.…”