Variety Of Vinyl Monomers Research Articles

Expanding the toolbox of controlled/living branching radical polymerization through simulation-informed reaction design

•A controlled/living branching polymerization was achieved •Mechanistic studies and kinetic simulations guided the reaction optimization •Branched polymers were synthesized from a broad range of vinyl monomers Branched polymers with superior mechanical, photonic, and electrical properties have shown their growing advantages in biomedical applications, water treatment, and catalysis. Anchoring branched functional motifs onto select molecular-/nano-objects introduces structural hierarchy as well as combined and enhanced properties. To realize efficient grafting of branched functional polymers, a controlled chain-growth branching polymerization is desirable but remains underexplored. In this article, the chain-growth process was achieved by copolymerizing α-haloacrylate with conventional vinyl monomers via atom transfer radical polymerization. We conducted systematic mechanistic studies to obtain an optimal profile of the polymerization conditions, where an activator regeneration approach was employed. Assisted by kinetic simulations, a variety of vinyl monomers, including acrylates, styrene, acrylonitrile, and acrylamides, were successfully copolymerized with α-haloacrylate with high monomer conversion to produce well-defined branched polymers with tunable degrees of branching. The impact of controlled branching on the thermoresponsive properties was studied using the synthesized poly(N-isopropylacrylamide). Branched polymers with superior mechanical, photonic, and electrical properties have shown their growing advantages in biomedical applications, water treatment, and catalysis. Anchoring branched functional motifs onto select molecular-/nano-objects introduces structural hierarchy as well as combined and enhanced properties. To realize efficient grafting of branched functional polymers, a controlled chain-growth branching polymerization is desirable but remains underexplored. In this article, the chain-growth process was achieved by copolymerizing α-haloacrylate with conventional vinyl monomers via atom transfer radical polymerization. We conducted systematic mechanistic studies to obtain an optimal profile of the polymerization conditions, where an activator regeneration approach was employed. Assisted by kinetic simulations, a variety of vinyl monomers, including acrylates, styrene, acrylonitrile, and acrylamides, were successfully copolymerized with α-haloacrylate with high monomer conversion to produce well-defined branched polymers with tunable degrees of branching. The impact of controlled branching on the thermoresponsive properties was studied using the synthesized poly(N-isopropylacrylamide).

Enzyme-initiated free radical polymerizations of vinyl monomers using horseradish peroxidase.

In this chapter, we highlight the use of horseradish peroxidase (HRP) as a catalyst to initiate free radical polymerizations of vinyl monomers under benign reaction conditions. A variety of vinyl monomers, including 4-acryloylmorpholine (AM), 2-hydroxyethyl methacrylate (HEMA), and poly(ethylene glycol) methyl ether acrylate (PEGA) were polymerized. The enzyme converts exogenous hydrogen peroxide into a usable radical source, which when coupled with a β-diketone, yields a radical that initiates chain growth in the presence of monomers. The resulting polymers were characterized using nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). By using enzymatic free radical polymerizations, polymers can be generated in a sustainable, environmentally-friendly, and scalable fashion.

Synthesis of polymers carrying adamantyl substituents in side chain

This review addresses the synthesis of various polymers carrying bulky and rigid adamantyl substituents in their side chains. Synthetic methods for these polymers include typical polymer reactions of introducing adamantyl groups into existing polymers and the polymerization of monomers bearing pendant adamantyl groups. In particular, with regard to the latter synthetic method, the addition polymerization of adamantyl-containing vinyl monomers such as α-olefins, acetylenes, (meth)acrylates, (meth)acrylamides, vinyl ethers, 1,3-dienes, and styrenes is described. A variety of vinyl monomers are capable of undergoing living anionic polymerization to afford polymers with predictable molecular weights and narrow molecular weight distributions (M w/M n = 1.1). In several cases, the introduced adamantyl groups afford steric hindrance to prevent side reactions and control the addition modes of the polymerization. In general, the resulting adamantyl-substituted polymers show extremely high glass transition temperatures and high thermal stability derived from the stiff adamantyl substituents compared with the corresponding parent polymers. This review deals with the synthesis of various polymers carrying bulky and rigid adamantyl substituents in the side chain. The synthetic methods of those polymers include the typical polymer reaction by introducing adamantyl groups to the present polymers and the polymerization of the monomers bearing the adamantyl pendant groups. A variety of vinyl monomers, such as styrenes, 1,3-butadiene, and (meth)acrylates, are capable of the living anionic polymerization to afford the polymers having predictable molecular weights and narrow molecular weight distributions (Mw/Mn =1.1). The resulting adamantyl-substituted polymers show extremely high glass transition temperatures and high thermal stability derived from the stiff adamantyl substituents compared with the corresponding parent polymers.

Extremely stretchable thermosensitive hydrogels by introducing slide-ring polyrotaxane cross-linkers and ionic groups into the polymer network.

Stimuli-sensitive hydrogels changing their volumes and shapes in response to various stimulations have potential applications in multiple fields. However, these hydrogels have not yet been commercialized due to some problems that need to be overcome. One of the most significant problems is that conventional stimuli-sensitive hydrogels are usually brittle. Here we prepare extremely stretchable thermosensitive hydrogels with good toughness by using polyrotaxane derivatives composed of α-cyclodextrin and polyethylene glycol as cross-linkers and introducing ionic groups into the polymer network. The ionic groups help the polyrotaxane cross-linkers to become well extended in the polymer network. The resulting hydrogels are surprisingly stretchable and tough because the cross-linked α-cyclodextrin molecules can move along the polyethylene glycol chains. In addition, the polyrotaxane cross-linkers can be used with a variety of vinyl monomers; the mechanical properties of the wide variety of polymer gels can be improved by using these cross-linkers.

New chain transfer agents for radical polymerization based on the addition‐fragmentation mechanism

AbstractThis study describes 15 compounds with allylic or pentadienic structure carrying either captodative (cd) carbon‐ or heteroatom substituents as potential radical leaving groups in an addition‐fragmentation reaction. Their experimental evaluation as chain‐transfer agents (CTA) was achieved in radical polymerization of styrene and methyl methacrylate. The α‐(cd‐substituted methyl)acrylates 9 and 11 were more efficient than the t‐thioether 10 in lowering molecular weight of polystyrene. The dienes are particularly effective and provide macromonomers with terminal diene functions which are very useful for further copolymerization with a variety of vinyl monomers.

N,N′‐(disubstitutedmethylene)bisacrylamides: Preparation and polymerization

AbstractPreparative methods for the previously unreported N,N′‐(disubstitutedmethylene)‐bisacrylamides are presented. The solubility and thermal stability of these new bisamides are compared to the well known N,N′‐methylenebisacrylamide. N,N′‐Isopropyl‐idenebisacrylamide, one of these new compounds, readily copolymerizes with a variety of vinyl monomers. It forms high molecular weight copolymers by the conjugate polyaddition of alkanedithiols or piperazine.

Nitrogen‐containing monomers. I. Copolymerization reactions of N‐alkyl maleamic acids and N‐alkyl maleimides

AbstractThe polymerization reactions of some N‐alkyl maleamic acids and N‐alkyl maleimides have been described and a number of copolymers have been characterized. The N‐alkyl maleamic acids do not homopolymerize under the conditions employed but do copolymerize with styrene, acrylonitrile, and methacrylates. N‐Alkyl maleimides form homopolymers readily and copolymerize with a variety of vinyl monomers. Reactivity ratios of N‐butyl maleimide with styrene and methyl methacrylate have been determined, and Q and e values have been calculated.