Sulfur-containing polyacrylates: V. Temperature effects on the photoinitiated polymerization of diacrylates (original) (raw)
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Polymer, 1996
The polymerization of three analogous monomersP2.2'-thiobisethanol dimethacrylate. 2.2'-oxybisethanol dimethacrylate and 1,5-pentanediol dimethacrylate-has been studied in the temperature range 3OG95"C by isothermal d.s.c. The temperature and heteroatom effects on the polymerization course were considered from the point of view of the occurrence and relative importance of hydrogen abstraction reaction which is manifested by chain transfer and chain peroxidation processes. Generally the advantageous effect of the sulfide group is revealed in reduction of oxygen inhibition and suppression of the drop of final conversion with increasing temperature above 70°C in the absence of oxygen. However, the influence of the sulfide group on the polymerization of dimethacrylates is not so great as on diacrylates due to various factors of both a physical and chemical nature. (Keywords: dimethacrylates; sulfide group; temperature effect on photopolymerization)
Journal of Polymer Science Part A-polymer Chemistry, 1993
The photo-and thermally induced polymerization of four analogous dimethacrylates2,2′-thiobisethanol dimethacrylate, 2,2′-oxybisethanol dimethacrylate, pentanediol-1,5-dimethacrylate, and butanediol-1,4-dimethacrylatewas studied to determine the influence ofSandOlinkages on the polymerization course. Generally, the presence of the heteroatom in the monomer molecule results in higher reaction rates and yields but the extent of this influence highly depends on the polymerization conditions and the type of heteroatom. The effect of the thioether bond exceeds the effect of the ether bond at lower (40°C) temperature in the presence of oxygen but the reverse situation takes place at higher (75°C) temperature and/or in an inert atmosphere when photofragmentating and thermal initiators are used. The results are discussed mainly in terms of propensity of sulfides and ethers to act as hydrogen donors and chain-transfer agents. © 1993 John Wiley & Sons, Inc.
Journal of Photochemistry and Photobiology A-chemistry, 1989
The photoinduced polymerization of 2,2′-thiobisethanol dimethacrylate was investigated in the presence of various amounts of oxygen. Benzophenone or benzophenone—aliphatic amine were used as sensitizers. To determine the influence of the sulphur linkage on the monomer reactivity, the polymerization of 2,2′-thiobisethanol dimethacrylate was compared with the polymerizations of 2,2′-oxybisethanol dimethacrylate and butanediol-1,4 dimethacrylate. It was found that the sulphur-containing monomer is much less sensitive to inhibition by oxygen. In the absence of oxygen the reactivities of the monomers are nearly the same.
Open Chemistry, 2005
The behavior of p-methoxybenzoyldiphenylphosphine oxide, previously synthesized, as a photoinitiator for the polymerization of diacrylate monomer, in the presence of 3 % (w/w) tertiary amine (triethyl amine) as synergist additive, was studied. The influence of temperature in the range 30-90 • C at 3 % (w/w) photoinitiator concentration and the influence of the photoinitiator concentration in the range 0.5-3.5 % (w/w) at 30 • C was investigated by differential scanning photocalorimetry (photo-DSC). In all experiments the photopolymerization was performed at constant light intensity (3 mW cm −2). The maximum conversion was obtained at temperature of 90 • C at 3 % (w/w) photoinitiator concentration and 3 % (w/w) triethyl amine. The optimal concentration of photoinitiator to obtain maximum conversion was 3 % (w/w), at 30 • C. No thermal polymerization occurred at higher temperature.
Temperature effects on the kinetics of photoinitiated polymerization of dimethacrylates
Polymer, 1991
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Polymerization kinetics of photocurable acrylic resins
Journal of Polymer Science Part A: Polymer Chemistry, 1998
The polymerization kinetics of photocurable compositions based on an epoxyacrylate oligomer and three analogous diacrylate monomers were investigated. The effects of the oligomer-to-monomer ratio, curing conditions, and monomer structure were considered. The polymerization is characterized by a synergistic effect observed in a wide temperature range and occurring for the polymerization rate both in air and Ar and for final conversions in air. The final conversion in Ar is determined by viscosity of a formulation. The presence of a heteroatom (S or O) in the ester group of the reactive diluent is beneficial for the polymerization course, especially in air atmosphere. The best results were obtained for the sulfur-containing monomer.
Polymer, 2001
UV-light initiation is now commonly used to induce polymerization of multifunctional monomers. The highly crosslinked networks obtained have a wide variety of applications. The thermal effects which take place during polymerization can be the cause of non-homogeneity and defects in the ®nal material. These defects greatly alter the physical properties of the ®nal products, particularly the optical ones, which causes problems in the design of thick and optically perfect materials. To better control the homogeneity of photocured materials and to determine the in¯uence of different experimental parameters on them, conversion and temperature distribution pro®les within a material during photopolymerization were simulated numerically, using the general heat equation applied to one-dimensional system. To describe the true conditions of kinetic experiments, some necessary parameters were measured, like conversion, reaction rate, spectral irradiance of the Hg vapor lamp and dimethacrylate spectral absorbance. We focused our attention more particularly on the in¯uence of the irradiation wavelength. Indeed, the high values of the spectral absorbance coef®cient cause a great decrease in light intensity in the depth of the material and lead in turn to a sharp drop in conversion.