Kinetics of the free-radical copolymerization of methyl methacrylate/ethylene glycol dimethacrylate: 1. Experimental investigation

Li, W.-H.; Hamielec, A. E.; Crowe, C. M.

doi:10.1016/0032-3861(89)90225-5

Cited by 81 publications

(76 citation statements)

References 14 publications

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“…Thus, when the input values are 5 %T and only 0.14%C, the gel point conversion value is as high as 41.3 */ o (total monomers), whereas, at the opposite extreme, when the initial feed is 10 %T and 10 %C, the p , value is only 16.4% (total monomers). Interestingly, this trend had been predicted (and measured) independently by Li et al [33] (see their Fig. 9) in the case of copolymerization of methyl methacrylate with ethylene glycol dimethacrylate as crosslinker: a 50% total monomer conversion is found when %C is barely0.3, but when %C is 2%, the gel point occurs at only 10% total monomer conversion; however, as a criticism to their data, it appears that, for %C>6, the conversion at gel point tends to zero, which is a weird prediction, to say the least!…”

Section: On the Extent Of Monomer Incorporation At The Gel Pointmentioning

confidence: 55%

On the kinetics of monomer incorporation into polyacrylamide gels, as investigated by capillary zone electrophoresis

Righetti

Caglio

1993

Electrophoresis

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The kinetics of monomer incorporation into a polyacrylamide gel have been studied in a photopolymerization system comprising 100 microM methylene blue in presence of a red-ox system, 1 mM sodium toluenesulfinate (reducer) and 50 microM diphenyliodonium chloride (oxidizer). A precise assessment of gel point (pc) was obtained in a droplet chamber, in which argon was gently bubbled with a fused silica capillary into the reaction mixture. At pc, 50% (+/- 3) acrylamide was incorporated into the matrix, vs. 80% (+/- 4) N,N'-methylenebisacrylamide. This incorporation level remained the same when polymerized in the 2-36 degrees C temperature range. Incorporation continued almost linearly for acrylamide up to 80% conversion. The reaction was continued up to 55 min (at 2 degrees C), at which point bisacrylamide had been essentially consumed (> 99.5% incorporation) and acrylamide had reacted (95%). At 2 degrees C, after gelation, the gel became progressively turbid (the Tyndall effect plateauing at 50 min), but it remained fully transparent if, at the gel point, reaction was continued at 50 degrees C. The consumption of the pendant double bonds of Bis followed the progression of turbidity. It is concluded that, by gelation at 2 degrees C, the nascent chains form clusters held together by hydrogen bonds (melting point at 28 degrees C); such clusters are subsequently "frozen" in the three-dimensional space as the pendant double bonds in the chains react progressively. Such turbid matrices are more porous and less elastic than when the gel is polymerized at 50 degrees C. This process is similar to the "lateral aggregation" occurring when gels are formed in presence of a polymer in solution (e.g. 10 KDa polyethylene glycol; Righetti et al., Electrophoresis 1992, 13, 587-594).

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Section: On the Extent Of Monomer Incorporation At The Gel Pointmentioning

confidence: 55%

On the kinetics of monomer incorporation into polyacrylamide gels, as investigated by capillary zone electrophoresis

Righetti

Caglio

1993

Electrophoresis

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“…Several experimental works can be found in the literature about batch copolymerization of mono-and divinylmonomers of different chemical compositions and polymerization conditions [1][2][3][4][5][6]. Other recent works in this subject [7,8] are examples witnessing the experimental efforts on studying the formation of crosslinked networks.…”

Section: Modeling Of Non-linear Free-radical Polymerization: a Summarmentioning

confidence: 99%

Semibatch operation and primary cyclization effects in homogeneous free-radical crosslinking copolymerizations

Dias

Costa

2005

Polymer

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A theoretical analysis is presented on the use of semibatch reactors for producing non-linear copolymers through the homogeneous freeradical polymerization of mono-and divinyl-monomers. The kinetic scheme distinguishes two kinds of pendant double bonds and five kinds of polymer radicals, as it also takes into account the primary cyclization of terminal divinyl units. In spite of the fairly large number of groups and reactions, the generating function of vector chain length distribution of polymer species can still be accurately computed by a numerical implementation of the method of characteristics and thus average molecular weights before and after gelation can be reliably obtained. The influence of feed policies of the monomers, initiator and transfer agent on gelation, average chain lengths and weight fraction of sol is discussed, as well as their sensitivity to some kinetic parameters.

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“…An increase in the polymerization temperature from 60 to 708C could potentially increase the degree of crosslinking resulting in the formation of smaller pores; however, a fine balance between the achievable porosity and the particle size of the resultant polymer beads requires careful optimization by controlling confounded parameters during polymer synthesis. While apparently a straightforward synthetic route, the precipitation polymerization method is not the best method of choice for templates with limited availability, as the yield of microspheres is relatively low (40 -60%) [57] in contrast to particles obtained via bulk polymerization (90%; however, a significant amount of particles were not usable after grounding and sieving) [58], which results from the reduced monomer and initiator loading, along with the generation of soluble polymer resulting from the amount of crosslinking monomers required for this method [57]. However, if low-cost dummy templates can be utilized [26,59], this synthetic route may provide a viable strategy.…”

Section: Directly Synthesized Polymer Beadsmentioning

confidence: 94%

Recent advances on noncovalent molecular imprints for affinity separations

Wei

Mizaikoff²

2007

J of Separation Science

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Molecularly imprinted polymers (MIPs) are tailor-made synthetic materials capable of selectively rebinding a target analyte, or a group of structurally related compounds based on a combination of recognition mechanisms including size, shape, and functionality. Among the advantageous properties of MIPs are the achievable specific affinity, the relative ease of preparation, and their mechanical and chemical robustness, which renders them ideal materials for applications as stationary phase (e. g., affinity chromatography or SPE), or as antibody mimics (e. g., biomimetic assays). Here, we review recent advancements on the application of MIPs in affinity separations and biomimetic assays, which have focused on the synthesis of size- and shape-uniform particles facilitating reproducibility, improved binding site accessibility, and enhanced affinity. While MIPs certainly offer promising potential as selective separation phase in a variety of applications, deeper understanding of the fundamental interactions governing imprinting, and rational understanding of the imprinting mechanism has yet to be achieved for providing rational guidelines in deliberately designing next-generation MIP materials.

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Kinetics of the free-radical copolymerization of methyl methacrylate/ethylene glycol dimethacrylate: 1. Experimental investigation

Cited by 81 publications

References 14 publications

On the kinetics of monomer incorporation into polyacrylamide gels, as investigated by capillary zone electrophoresis

On the kinetics of monomer incorporation into polyacrylamide gels, as investigated by capillary zone electrophoresis

Semibatch operation and primary cyclization effects in homogeneous free-radical crosslinking copolymerizations

Recent advances on noncovalent molecular imprints for affinity separations

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