“…NAS is an activated ester-type monomer: − the presence of the electron-withdrawing succinimide moiety renders the carbonyl carbon of the ester susceptible to nucleophilic substitution reactions. NAS has been employed as a functional monomer in various copolymers to impart a range of desired properties and capabilities. − 2 Structures of N -Acryloxysuccinimide (NAS) (1), n -Butyl Methacrylate (BMA) (2), 2-{[(Dodecylsulfanyl)carbonothioyl]sulfanyl}- propanoic Acid (3), Benzyl 2-(2-Hydroxyethylamino)-1-methyl-2-oxoethyl Trithiocarbonate (4), 2-Phenylpropyl Phenyldithioacetate (5), and 2-Cyanopropyl Dithiobenzoate (6) …”
Section: Introductionmentioning
confidence: 99%
“…NAS has been employed as a functional monomer in various copoly-mers to impart a range of desired properties and capabilities. [44][45][46][47][48][49][50][51][52] To ensure a truly random distribution of branches along a poly(BMA-co-NAS-graft-BMA) molecule, a random distribution of potential branch points must be present in the "parent" chain. To achieve this, the free radical copolymerization kinetics of BMA and NAS were investigated and reactivity ratios for the BMA-and NAS-terminated polymer radicals determined, assuming the terminal model.…”
Comblike polymers of poly(n-butyl methacrylate) were prepared using an activated estertype comonomer (N-acryloxysuccinimide, NAS) to generate branch points. The conventional solution freeradical copolymerization kinetics of n-butyl methacrylate (BMA) and NAS were first investigated by following individual monomer consumption rates by 1 H NMR spectrometry and reactivity ratios of BMA and NAS determined using the terminal model. The reactivity ratios so obtained are both close to 0.2; the joint confidence interval is also determined. Reversible addition-fragmentation chain transfer (RAFT) was then used to grow polymers with controlled backbone and branch chain length. Because both reactivity ratios have similar values, this implies that the copolymer will have a random distribution of NAS and hence of branch points. RAFT-mediated polymerization was first used to synthesize linear poly(BMAco-NAS) chains. Primary hydroxy-functionalized RAFT agents were then immobilized on this linear poly-(BMA-co-NAS) through nucleophilic substitution on the activated ester units of the NAS. From these immobilized RAFT agents, branches were grown upon addition of a further aliquot of monomer (BMA) and initiator (AIBN). The amount of NAS in the starting BMA/NAS composition was varied without adversely affecting the uniformity of the NAS distribution along the resulting linear poly(BMA-co-NAS) backbone. This results in branched polymers whose molecular weight, branching density, and degree of polymerization of branches are all relatively narrow and controlled.
“…NAS is an activated ester-type monomer: − the presence of the electron-withdrawing succinimide moiety renders the carbonyl carbon of the ester susceptible to nucleophilic substitution reactions. NAS has been employed as a functional monomer in various copolymers to impart a range of desired properties and capabilities. − 2 Structures of N -Acryloxysuccinimide (NAS) (1), n -Butyl Methacrylate (BMA) (2), 2-{[(Dodecylsulfanyl)carbonothioyl]sulfanyl}- propanoic Acid (3), Benzyl 2-(2-Hydroxyethylamino)-1-methyl-2-oxoethyl Trithiocarbonate (4), 2-Phenylpropyl Phenyldithioacetate (5), and 2-Cyanopropyl Dithiobenzoate (6) …”
Section: Introductionmentioning
confidence: 99%
“…NAS has been employed as a functional monomer in various copoly-mers to impart a range of desired properties and capabilities. [44][45][46][47][48][49][50][51][52] To ensure a truly random distribution of branches along a poly(BMA-co-NAS-graft-BMA) molecule, a random distribution of potential branch points must be present in the "parent" chain. To achieve this, the free radical copolymerization kinetics of BMA and NAS were investigated and reactivity ratios for the BMA-and NAS-terminated polymer radicals determined, assuming the terminal model.…”
Comblike polymers of poly(n-butyl methacrylate) were prepared using an activated estertype comonomer (N-acryloxysuccinimide, NAS) to generate branch points. The conventional solution freeradical copolymerization kinetics of n-butyl methacrylate (BMA) and NAS were first investigated by following individual monomer consumption rates by 1 H NMR spectrometry and reactivity ratios of BMA and NAS determined using the terminal model. The reactivity ratios so obtained are both close to 0.2; the joint confidence interval is also determined. Reversible addition-fragmentation chain transfer (RAFT) was then used to grow polymers with controlled backbone and branch chain length. Because both reactivity ratios have similar values, this implies that the copolymer will have a random distribution of NAS and hence of branch points. RAFT-mediated polymerization was first used to synthesize linear poly(BMAco-NAS) chains. Primary hydroxy-functionalized RAFT agents were then immobilized on this linear poly-(BMA-co-NAS) through nucleophilic substitution on the activated ester units of the NAS. From these immobilized RAFT agents, branches were grown upon addition of a further aliquot of monomer (BMA) and initiator (AIBN). The amount of NAS in the starting BMA/NAS composition was varied without adversely affecting the uniformity of the NAS distribution along the resulting linear poly(BMA-co-NAS) backbone. This results in branched polymers whose molecular weight, branching density, and degree of polymerization of branches are all relatively narrow and controlled.
“…Some of these groups must be activated prior to protein immobilization (e.g., hydroxyl groups with cyanogen bromide and carboxyl groups with carbodiimide , ). Other groups could be used for protein immobilization without additional activation (e.g., aldehyde, − succinimide, and vinylbenzyl chloride − ). The potential to improve reagent shelf life and more defined orientation of bound ligand are the main advantages of covalent attachment.…”
The functionalized core-shell monodisperse latex particles with surface chloromethyl groups were synthesized by means of a two-step emulsion polymerization process in a batch reactor at two reaction temperatures. In a first step, the core was synthesized by means of a batch emulsion polymerization of styrene (St), and in the second step, the shell was formed by batch emulsion copolymerization of St and (chloromethyl)styrene (CMS) using the seed obtained previously. The latexes were characterized by TEM and conductopotentiometric titrations in order to obtain the particle size distribution and the amount of the different surface groups, respectively. Covalent binding of protein to chloromethyl groups was studied using lysozyme at two pHs, 7 and 11. Two different methods were used to determine the amount of protein covalently bound or physically adsorbed: desorption with surfactants, and chloride ions release upon chemical binding.
“…With this in mind, some authors have devised methods of preparing particles from activated monomers such as l-(methacryloxy)benzotriazole and N-( acryloxy )succinimide. [27][28][29] Of the more unusual materials used for latex preparation, those based on the vinyl pyridines are particularly useful.1•30 These particle systems can be prepared in a single step up to 15 ^m in size and can be linked to proteins using cyanogen bromide activation. In addition, vinyl pyridines complex with transition metal ions to form colored latices and complex with electron-dense metals such as gold for electron microscopy applications.30…”
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