Interfacial (polymer‐substrate) failure of ultraviolet radiation curable coatings

McGinniss, V. D.; Kah, A. F.

doi:10.1002/pen.760170711

Cited by 15 publications

(6 citation statements)

References 6 publications

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“…Rate coefficients for reactions , , and were calculated in aqueous phase using both the M06‐2X/6‐311++G (3df, 2p)//B3LYP/6‐31+G (d, p) and M06‐2X/6‐311++G (3df, 2p)//CAM‐B3LYP/6‐31+G (d, p) schemes to evaluate the ability of the B3LYP and CAM‐B3LYP functionals to reproduce the chemistry of the SO 4 • — radical anion. Table shows overall rate coefficients calculated using both schemes along with experimental constants and the error between experimental and calculated free energy barriers of reactions

| Δ G_{\exp}^{\neq} - Δ G_{calc}^{\neq} |

. Gibbs free energy barriers, reaction path degeneracies, and tunneling correction factors are shown in Tables S9–S16 in the Supporting Information for both s‐cis and s‐trans conformers of each monomer in reactions , , and .…”

Section: Resultsmentioning

confidence: 99%

Theoretical Study of Reactions between Oxygen-Centered Radicals (^•OH and SO₄^•-) and Vinyl Monomers in Aqueous Phase

Hoz

Konstantinov

Arturo

et al. 2016

Macromol. Theory Simul.

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In this work, reactions between industrially relevant monomers (methyl acrylate, ethyl acrylate, methyl methacrylate, vinyl acetate, and isopropenyl acetate) and oxygen‐centered radicals (•OH and SO4 •—) are studied using a combination of quantum mechanics and transition state theory. These reactions may have a strong influence on polymer structure and properties. Thus, computational methodologies able to estimate reliably coefficients for these reactions are needed to improve the understanding of emulsion polymerization processes. In the case of reactions involving •OH, the computational approach is based on the SMD‐water/M06‐2X/6‐311++G(3df, 2p)//B3LYP/6‐31+G(d, p) DFT scheme. All calculated and experimental Gibbs free energy barriers, |ΔGexp≠−ΔGcalc≠|, are within 1 kcal mol−1. In the case of reactions involving SO4•—, the SMD‐water/M06‐2X/6‐311++G(3df, 2p)//CAM‐B3LYP/6‐31+G(d, p) DFT scheme is found to be more suitable than a similar scheme based on B3LYP. This proposed scheme works well for acrylates and methacrylates (errors within 1 kcal mol−1), but it may overestimate the rate coefficients of acetates reacting with SO4•—.

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| Δ G_{\exp}^{\neq} - Δ G_{calc}^{\neq} |

Section: Resultsmentioning

confidence: 99%

Theoretical Study of Reactions between Oxygen-Centered Radicals (^•OH and SO₄^•-) and Vinyl Monomers in Aqueous Phase

Hoz

Konstantinov

Arturo

et al. 2016

Macromol. Theory Simul.

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“…Because SO 4 •- radicals are very reactive toward vinyl groups, blank experiments consider the reaction of sulfate radicals with VA and 4-VP in the absence of silica NP. The rate constant for reaction (R6) for VA, k 6VA = (1.5 ± 1.0) × 10 9 M -1 s -1 , is reported in the literature. , However, no information has been found for the rate constant of the reaction between sulfate radicals and 4-VP, despite the fact that this reaction has been extensively used for initiating the polymerization of 4-VA. ,,, We will therefore first describe experiments designed to measure this rate constant.…”

Section: Resultsmentioning

confidence: 99%

Kinetic Studies on the Sulfate Radical-Initiated Polymerization of Vinyl Acetate and 4-Vinyl Pyridine in the Presence of Silica Nanoparticles

et al. 2005

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The photolysis of silica suspensions of pH approximately 8 containing peroxodisulfate ions leads to the generation of two "surface transients" with a distinct spectrum and reactivity. Time-resolved and continuous irradiation experiments of similar dispersions also containing variable concentrations of vinyl acetate (VA) or 4-vinyl pyridine (4-VP) allowed the evaluation of the contribution of silica/water interfacial reactions to the kinetics and structural pattern of polymers synthesized using sulfate radicals as initiators. The rate constants measured for the reactions of the surface transients with 4-VP are 1 order of magnitude higher than those of VA, despite the fact that both species show similar reactivity in homogeneous solution toward sulfate radicals. It is suggested that both the sorption capacity and the different specific interactions with the silica surface of 4-VP and VA contribute to the observed reaction rates. Micrometer-sized latex particles of 4-VP and VP showed higher stability and more homogeneous size distributions when obtained in the presence of silica nanoparticles. Under the experimental conditions required for obtaining polymer particles, both the contribution of the described interfacial reactions and the effect of silica adsorbed monomer on the initiation steps of the polymerization may be neglected. The importance of in situ adsorption of the oligomer/polymer chains to silica NP during the polymerization propagation steps in determining the particle morphology is discussed.

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“…In the reactions of the highly electrophilic sulfate radical with MMA and VAc as shown in Fig. 3, addition McGinniss and Kah reported that the reaction rate constant of the sulfate radical with MMA (1.26·10 9 L·mol -1 ·s -1 ) was slightly lower than with VAc (1.52·10 9 L·mol -1 ·s -1 ) [14,15]. However, it should be noted that these are not the addition rate constants of the sulfate radical to the monomers but the constants of decay of the sulfate radical in presence of the monomers.…”

Section: Resultsmentioning

confidence: 99%

Surface sulfate groups on poly(methyl methacrylate) and poly(vinyl acetate) particles from soap-free emulsion polymerization

et al. 2005

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Abstract:The amounts of sulfate groups on the particle surfaces of poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVAc) obtained in soap-free emulsion polymerization were determined. Polymerization was carried out at low monomer concentration using ammonium persulfate as an initiator. After the ionexchange procedure, conductometric titration was carried out. Amounts of surface sulfate groups were lower and particle diameter was larger in the PMMA system compared with PVAc. A large and remarkable difference appeared in the ratio of surface sulfate groups to decomposed sulfate radicals, viz. 90% for the PVAc system and 50% for PMMA. The ratios of sulfate groups per polymer molecule on PMMA and PVAc particles (functionality) were calculated. The functionality of the PMMA system was 70% of the theoretical value, while it was close to 100% in the PVAc system. This large difference might arise from the weak reactivity of the sulfate radical with MMA compared with that of VAc, due to the strong electrophilic nature of the radical. A side reaction of the sulfate radical with MMA is assumed. On the basis of these experimental results, the instability of the emulsion polymerization of acrylic monomers using poly(vinyl alcohol) (PVA) as a protective colloid is discussed in terms of the instability of the soap-free particles formed after the consumption of free PVA in water by the grafting reaction.

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Interfacial (polymer‐substrate) failure of ultraviolet radiation curable coatings

Cited by 15 publications

References 6 publications

Theoretical Study of Reactions between Oxygen-Centered Radicals (^•OH and SO₄^•-) and Vinyl Monomers in Aqueous Phase

Theoretical Study of Reactions between Oxygen-Centered Radicals (^•OH and SO₄^•-) and Vinyl Monomers in Aqueous Phase

Kinetic Studies on the Sulfate Radical-Initiated Polymerization of Vinyl Acetate and 4-Vinyl Pyridine in the Presence of Silica Nanoparticles

Surface sulfate groups on poly(methyl methacrylate) and poly(vinyl acetate) particles from soap-free emulsion polymerization

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Interfacial (polymer‐substrate) failure of ultraviolet radiation curable coatings

Cited by 15 publications

References 6 publications

Theoretical Study of Reactions between Oxygen-Centered Radicals (•OH and SO4•-) and Vinyl Monomers in Aqueous Phase

Theoretical Study of Reactions between Oxygen-Centered Radicals (•OH and SO4•-) and Vinyl Monomers in Aqueous Phase

Kinetic Studies on the Sulfate Radical-Initiated Polymerization of Vinyl Acetate and 4-Vinyl Pyridine in the Presence of Silica Nanoparticles

Surface sulfate groups on poly(methyl methacrylate) and poly(vinyl acetate) particles from soap-free emulsion polymerization

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Theoretical Study of Reactions between Oxygen-Centered Radicals (^•OH and SO₄^•-) and Vinyl Monomers in Aqueous Phase

Theoretical Study of Reactions between Oxygen-Centered Radicals (^•OH and SO₄^•-) and Vinyl Monomers in Aqueous Phase