Efficient stabilization of thiol-ene formulations in radical photopolymerization

Esfandiari, Paricher; Ligon, Samuel Clark; Lagref, Jean Jacques; Frantz, Richard; Cherkaoui, Zoubair M.; Liska, Robert

doi:10.1002/pola.26848

Cited by 88 publications

(92 citation statements)

References 27 publications

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“…The limited shelf‐life stability of thiol–enes may be also caused by a base‐catalyzed nucleophilic addition of thiol to the ene double bond . Recently, Liska and coworkers described an efficient stabilizer system for thiol–ene formulations based on the combination of a free radical scavenger and an acid with an appropriate p K a value. Thus, the combination of a moderately strong acid coadditive such as the phenyl phosphonic acid (pK a = ∼2) with a small amount of pyrogallol (0.1% wt) was also tested for AMC.…”

Section: Resultsmentioning

confidence: 99%

An efficient nonisocyanate route to polyurethanes via thiol‐ene self‐addition

Calle

Lligadas

Ronda

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

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A novel and efficient strategy for the synthesis of nonisocyanate polyurethanes has been developed via thiol–ene self‐photopolymerization. An aliphatic thiol–ene carbamate monomer (allyl(2‐mercaptoethyl)carbamate, AMC) was synthesized by a one‐step synthesis procedure, from cysteamine and allyl chloroformate. The urethane group was therefore incorporated directly into the monomer precursor, avoiding the problems associated to toxic isocyanates. AMC was successfully stabilized with the radical inhibitor pyrogallol (1% wt). In addition, the use of phenyl phosphonic acid as coadditive allowed its stabilization for lower concentrations of pyrogallol (0.1% wt). AMC was directly transformed into thermoplastic polyurethane (TPU) through thiol–ene photopolymerization by UV‐irradiation at 365 nm. The obtained TPU presented semi‐crystalline nature and very high thermal stability (T5% ∼325 °C). It was found that high concentrations of pyrogallol decreased the reaction rate and final conversion of photopolymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3017–3025

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Section: Resultsmentioning

confidence: 99%

An efficient nonisocyanate route to polyurethanes via thiol‐ene self‐addition

Calle

Lligadas

Ronda

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

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“…All three formulations were then homogenized in an ultrasonic bath for ≈30 min. In addition, the thiol‐based formulation (2M/EDDT) was stabilized by 9 × 10 −3 m PG and 90 × 10 −3 m MA …”

Section: Methodsmentioning

confidence: 99%

Investigating the Free‐Volume Characteristics of Regulated Dimethacrylate Networks Below and Above Glass Transition Temperature

Švajdlenková

Šauša

Maťko

et al. 2018

Macro Chemistry & Physics

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Studying the relationship between microstructural interactions and resulting macroscopic material properties gives a more elaborate understanding on final material performance. The microstructural arrangement with characteristic length, relaxation, and thermal expansion behavior of regulated dimethacrylate networks is studied by differential scanning calorimetry, dynamic mechanical analysis, thermomechanical analysis, and positron annihilation lifetime spectroscopy at a broad temperature range (250–380 K). The length scale ξ (Tg) of cooperative segmental rearrangement is decreased with increasing crosslinking and degree of freedom in regulated chain transfer agent (CTA)‐based networks. The macro and microscopic thermal expansion coefficients are determined in the glassy and rubbery state for three polymer systems—a dimethacrylate‐based reference (poly2M) and regulated photopolymers with CTAs (i.e., thiol, β‐allyl sulfone). The influence of CTAs on the free volume characteristics (i.e., free volume void size, the specific occupied volume V0, free volume number density per unit mass N′, and free volume fraction f) at the glass transition temperature Tg is correlated with the cooperative length, activation energy Ea,α, and mechanically effective crosslinking density. A more complex understanding of the revealed relations contributes to a more elaborate explanation of final material performance.

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“…Although vinyl esters are generally not as reactive as their acrylate analogs, our recent work demonstrated that the thiol-ene photo-click chemistry could greatly improve the reactivity of vinyl esters even to the level of acrylates [37]. Moreover, it is important to mention that the poor storage stability related to thiol-ene systems have recently been solved by using a combination of radical and acidic stabilizing system [38]. All these aspects suggest that water-soluble vinyl esters are promising hydrogel precursors for photolithography-based AMTs and tissue engineering applications.…”

Section: Chemistry Of Hydrogel Formationmentioning

confidence: 95%

Additive manufacturing of photosensitive hydrogels for tissue engineering applications

et al. 2014

Self Cite

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Hydrogels are extensively explored as scaffolding materials for 2D/3D cell culture and tissue engineering. Owing to the substantial complexity of tissues, it is increasingly important to develop 3D biomimetic hydrogels with user-defined architectures and controllable biological functions. To this end, one promising approach is to utilize photolithography-based additive manufacturing technologies (AMTs) in combination with photosensitive hydrogels. We here review recent advances in photolithography-based additive manufacturing of 3D hydrogels for tissue engineering applications. Given the importance of materials selection, we firstly give an overview of water-soluble photoinitiators for single-and two-photon polymerization, photopolymerizable hydrogel precursors and light-triggered chemistries for hydrogel formation.Through the text we discuss the design considerations of hydrogel precursors and synthetic approaches to polymerizable hydrogel precursors of synthetic and natural origins. Next, we shift to how photopolymerizable hydrogels could integrate with photolithography-based AMTs for creating well-defined hydrogel structures. We illustrate the working-principles of both single-and two-photon lithography and case studies of their applications in tissue engineering. In particular, two-photon lithography is highlighted as a powerful tool for 3D functionalization/construction of hydrogel constructs with μm-scale resolution. Within the text we also explain the chemical reactions involved in two-photon-induced biofunctionalization and polymerization. In the end, we summarize the limitations of available hydrogel systems and photolithography-based AMTs as well as a future outlook on potential optimizations.

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Efficient stabilization of thiol-ene formulations in radical photopolymerization

Cited by 88 publications

References 27 publications

An efficient nonisocyanate route to polyurethanes via thiol‐ene self‐addition

An efficient nonisocyanate route to polyurethanes via thiol‐ene self‐addition

Investigating the Free‐Volume Characteristics of Regulated Dimethacrylate Networks Below and Above Glass Transition Temperature

Additive manufacturing of photosensitive hydrogels for tissue engineering applications

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