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Kinetic profiles of thermally induced autopolymerization of MMA in DMAC at 90 °C with a different MMA: DMAC v/v ratio; b) kinetic profiles of thermally induced autopolymerization of MMA in DMAC (v/v = 1:1) at 75, 80, and 90 °C, respectively.
Source publication
The thermally induced spontaneously initiated autopolymerization of methyl methacrylate (MMA) upon air exposure in amide-type polar solvents at 75-90℃ was unexpectedly observed and then investigated. We confirmed by using iodometric analysis that oligo(MMA peroxide)s in-situ formed at a moderate rate via thermally induced interpolymerization of MMA...
Contexts in source publication
Context 1
... latter could undertake sequential initiation under high temperature and give rise to poly(MMA)-block -oligo(MMA peroxide)-block -poly(MMA), as shown in Scheme 2. Such a technique has been exploited to prepare block copolymer via conventional radical polymerization with the sequential initiation of multifunctional radical initiators. [ 40-48 ] Figure 6 a shows that conversion-time profi les of the thermally induced autopolymerization of MMA in DMAC (MMA:DMAC v/v = 99:1, 9:1, 1:1, and 1:9) at 90 °C. It was easy to observe that the autopolymerization of MMA in DMAC underwent at a faster rate than that in DMF under the similar conditions. ...
Context 2
... example, the conversion could be 56% in 3 h in the mixture (MMA:DMAC v/v = 1:9). Figure 6 b displays the conversion-time curves of the autopolymerization of MMA in DMAC (v/v = 1:1) at 75, 80, and 90 °C, respectively. Clearly, the autopolymerization occurred at a signifi cant rate even at 75 °C and led to a conversion of about 23% in 3 h. ...
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Citations
... Moreover, higher temperatures were avoided in this work due to the risk of spontaneous autopolymerization of HEMA. This effect could be associated with the polymerization of the methacrylate group [49] at a range of 75-90°C. In addition, Seidel and Malmonge [50] have performed the polymerization of HEMA at 75°C for 2 h applying benzoyl peroxide as initiator. ...
The total or partial substitution of fossil raw materials by biobased materials from renewable resources is one of the great challenges of our society. In this context, the reaction under mild condition as enzyme-catalyzed esterification was applied to investigate the esterification of the biobased 10-undecenoic acid with 2-hydroxyethyl methacrylate (HEMA) to obtain a new diene ester monomer. The environmentally friendly enzymatic reaction presented up to 100% of conversion; moreover, the production of possible by-products was minimized controlling reaction time and amount of enzyme. Furthermore, the presence of chloroform was evaluated during the enzymatic reactions and despite high conversions with higher enzyme concentration, the solvent-free system showed fast kinetics even with 1.13 U/g substrates. In addition, the commercial immobilized lipases Novozym 435 and NS 88011 could be applied for up to 10 cycles keeping conversions about 90%. The scale-up of the reaction was possible and a purification procedure was applied in order to isolate the diene ester monomer 2-(10-undecenoyloxy)ethyl methacrylate, preserving its double bonds, which could allow a potential use of this product in the synthesis of new renewable polymers through techniques as metathesis, thiol-ene, or free-radical polymerization.
The oxidation of vinyl compounds such as styrene, α‐methylstyrene, methyl methacrylate, acrylonitrile with molecular oxygen in the presence of N‐hydroxyphthalimide have been studied. It was shown that the N‐hydroxyphthalimide is efficient in initiation of the oxidative polymerization of vinyl monomers. The products of the monomer oxidation at 66 °C and 1 atm of O2 are corresponding polyperoxides and low molecular carbonyl compounds. IR‐ and ¹H NMR spectroscopy confirm the alternating copolymer structure of polyperoxides with –O–O– bonds in the main chain. In the oxidative polymerization of vinyl monomers initiated with the mixtures of N‐hydroxyphthalimide and 2,2′‐azobisisobutyronitrile or benzoyl peroxide it was observed a synergistic effect of initiators’ action. N‐hydroxyphthalimide reacts with molecular oxygen, initiator radicals or monomer to form the phthalimide‐N‐oxyl radical, which participates in the chain initiation stage and does not participate in the termination stages, which leads to a synergistic effect.
