Thiol–enes: Chemistry of the past with promise for the future

Hoyle, Charles E.; Lee, Tai Yeon; Roper, Todd M.

doi:10.1002/pola.20366

Cited by 1,356 publications

(1,538 citation statements)

References 142 publications

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“…In this regard it is worth mentioning the pioneering work of Morgan and Ketley, 43 who used benzophenone to absorb light and initiate the polymerization of the radical chain process via a hydrogen abstraction reaction involving the excited benzophenone and a ground-state thiol. The thiol-ene photopolymerization system has recently been revitalized 44,45 and used as an effective way to cross-link thermoplastic elastomers. 46,47 These reactions were also utilized as environmentally friendly "click" coupling processes in various synthetic applications, since in contrast to the other methods, they usually proceed in the absence of solvent under benign reaction conditions without the use of any potentially toxic metal.…”

Section: Free Radical Systemsmentioning

confidence: 99%

Photoinitiated Polymerization: Advances, Challenges, and Opportunities

2010

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The use of photoinitiated polymerization is continuously growing in industry as reflected by the large number of applications in not only conventional areas such as coatings, inks, and adhesives but also high-tech domains, optoelectronics, laser imaging, stereolithography, and nanotechnology. In this Perspective, the latest developments in photoinitiating systems for free radical and cationic polymerizations are presented. The potential use of photochemical methods for step-growth polymerization is also highlighted. The goal is, furthermore, to show approaches to overcome problems associated with the efficiency, wavelength flexibility, and environmental and safety issues in all photoinitiating systems for different modes of activation. Much progress has been made in the past 10 years in the preparation of complex and nanostructured macromolecules by using photoinitiated polymerizations. Thus, the new and emerging applications of photoinitiated polymerizations in the field of biomaterials, surface modification, preparation of block and graft copolymers, and nanocomposites have been addressed.

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Section: Free Radical Systemsmentioning

confidence: 99%

Photoinitiated Polymerization: Advances, Challenges, and Opportunities

2010

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“…[12] Thiol-ene resins polymerize via a step-growth mechanism, rather than the chain-growth mechanism characteristic of dimethacrylate resins, resulting in delayed gel point and enhanced control of the polymerization. [13] Thiol-ene polymerization results in reduced volume shrinkage and with the delayed gelation promote significant reductions in shrinkage stress. Nonetheless, the reduction in volume shrinkage in thiol-ene systems implies a reduction in cross-link density; therefore, one of the drawbacks of thiol-ene systems is that they generally exhibit reduced mechanical properties in comparison with dimethacrylate-based systems.…”

Section: Introductionmentioning

confidence: 99%

The effect of a dithiol spiroorthocarbonate on mechanical properties and shrinkage of a dental resin

Ortiz

Gómez

Duarte

et al. 2014

Designed Monomers and Polymers

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A novel spiroorthocarbonate with two thiol groups (SOC DITHIOL) was synthesized. This monomer was formulated with dimethacrylate monomers used in dental resins and photopolymerized with an LED dental lamp. The presence of the thiol groups in the monomer enabled it to react with the double bonds of the dimethacrylate monomers by means of the thiol-ene mechanism. Additionally, the SOC DITHIOL underwent cationic ring-opening polymerization, producing the corresponding poly(ether-carbonates). SOC DITHIOL was added to a formulation of a conventional acrylic resin, which includes a mixture of dimethacrylate monomers [glycerolate bisphenol A dimethacrylate (BIS-GMA)/ urethane dimethacrylate (UDMA)/triethyleneglycol dimethacrylate (TEGDMA)] in 50/30/20 M ratio). Concentration of the prepared SOC was varied in the above dimethacrylate formulation in the range of 5-30 mol%. Kinetics of photopolymerization were determined by means of real time Fourier transform infrared spectroscopy, finding that increasing concentrations of the SOC DITHIOL in the formulations, not only did not affect the photopolymerization rate of the acrylic resins, but it helped to increase the final conversion of the methacrylate groups. It was also found that the presence of SOC DITHIOL increased the elastic modulus of the resulting cross-linked polymer. The addition of 30% of SOC DITHIOL reduced shrinkage 59% in comparison with a sample without the SOC.

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“…The thiol-ene reaction 1 (the hydrothiolation of a C¼ ¼C bond) has recently attracted significant attention in the materials arena 2 because it displays many of the attributes of click chemistry. 3 Such additions can be accomplished under a Correspondence to: A.…”

Section: Introductionmentioning

confidence: 99%

“…B. Lowe (E-mail: andrew@ablowe. com) variety of experimental conditions including acid/ base catalysis, 4 nucleophile-mediated, 5,6 radicalmediated (often induced photochemically), 2,[7][8][9][10][11][12] and via a solvent promoted process. 13,14 However, the reaction is most commonly performed under radical conditions where it is applicable to many ene substrates, or under nucleophilic conditions with activated enes where the process proceeds via an anionic chain process, Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

Sequential thiol‐ene/thiol‐ene and thiol‐ene/thiol‐yne reactions as a route to well‐defined mono and bis end‐functionalized poly(N‐isopropylacrylamide)

Chan

Hoyle

et al. 2009

J. Polym. Sci. A Polym. Chem.

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211

191

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Sequential thiol-ene/thiol-ene and thiol-ene/thiol-yne reactions have been used as a facile and quantitative method for modifying end-groups on an N-isopropylacrylamide (NIPAm) homopolymer. A well-defined precursor of polyNIPAm (PNIPAm) was prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization in DMF at 70 C using the 1-cyano-1-methylethyl dithiobenzoate/2,2 0 -azobis(2-methylpropionitrile) chain transfer agent/initiator combination yielding a homopolymer with an absolute molecular weight of 5880 and polydispersity index of 1.18. The dithiobenzoate end-groups were modified in a one-pot process via primary amine cleavage followed by phosphine-mediated nucleophilic thiol-ene click reactions with either allyl methacrylate or propargyl acrylate yielding ene and yne terminal PNIPAm homopolymers quantitatively. The ene and yne groups were then modified, quantitatively as determined by 1 H NMR spectroscopy, via radical thiol-ene and radical thiol-yne reactions with three representative commercially available thiols yielding the mono and bis end functional NIPAm homopolymers. This is the first time such sequential thiol-ene/thiol-ene and thiol-ene/thiol-yne reactions have been used in polymer synthesis/end-group modification. The lower critical solution temperatures (LCST) were then determined for all PNIPAm homopolymers using a combination of optical measurements and dynamic light scattering. It is shown that the LCST varies depending on the chemical nature of the end-groups with measured values lying in the range 26-35 C.

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Thiol–enes: Chemistry of the past with promise for the future

Cited by 1,356 publications

References 142 publications

Photoinitiated Polymerization: Advances, Challenges, and Opportunities

Photoinitiated Polymerization: Advances, Challenges, and Opportunities

The effect of a dithiol spiroorthocarbonate on mechanical properties and shrinkage of a dental resin

Sequential thiol‐ene/thiol‐ene and thiol‐ene/thiol‐yne reactions as a route to well‐defined mono and bis end‐functionalized poly(N‐isopropylacrylamide)

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