Heat treatment effect on erosion behavior of poly(methylmethacrylate) for optical transmittance efficiency

Çoban, Onur

doi:10.1016/j.apsusc.2014.08.119

Cited by 4 publications

(2 citation statements)

References 59 publications

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“…The increase in intensities of asymmetric and symmetric stretching vibrations of CH 2 (at 2916 and 2848 cm −1 , respectively) could be explained by the cross-linking mechanism, leading to the formation of new intermolecular –CH 2 –CH 2 – bonds. 39-40 Plaček and Szőcs 41 used the electron spin resonance (ESR) method for studying radicals generated in PMMA by gamma-irradiation and they observed several types of radicals. In our opinion, one of the main radical they detected, –COOCH 2 ·, is probably responsible for the cross-linking observed in this study.…”

Section: Discussionmentioning

confidence: 99%

A comparative study of heat-cured and gamma-cured fiber-reinforced denture-base acrylic resins: Residual monomer and flexural strength

Ergün

Kalipçilar

2019

Polymers and Polymer Composites

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This study was performed to determine and compare the effect of heat and gamma-ray polymerization methods on the residual monomer and flexural strength of polyethylene fiber-reinforced denture-base acrylic resins. Four groups ( n = 10) of specimens of polyethylene fiber-reinforced denture-base material were prepared in the form of thin disks. The first group was subjected to heat-curing and the other three groups were polymerized with gamma irradiation at doses of 15, 25, and 35 kGy, respectively. Fourier-transform infrared (FTIR) spectrometer was used to monitor the corresponding polymerization processes. The analysis of residual monomer was carried out by high-performance liquid chromatography–photodiode array detector. A three-point bending test was used to evaluate the flexural strength of the samples. The one-way analysis of variance test was performed to determine the significant differences between the groups. The absence of the bands related to carbon–carbon double bond in the FTIR spectra of all test groups was an evidence of polymerization. The mean weight percentage of residual monomer was successively ranked from highest to lowest in; heat-cured, gamma-cured at 15–35 kGy. However, no significant difference ( p = 0.462) was found between gamma-cured samples at 25 and 35 kGy. Mechanical test results revealed that heat-cured samples had higher flexural strength than gamma-cured specimens ( p < 0.001). Within the limitations of this study, polymerization with gamma-rays at 15 kGy was proposed as a promising technique in terms of the residual monomer and flexural strength results.

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Section: Discussionmentioning

confidence: 99%

A comparative study of heat-cured and gamma-cured fiber-reinforced denture-base acrylic resins: Residual monomer and flexural strength

Ergün

Kalipçilar

2019

Polymers and Polymer Composites

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“…During scintillation measurements, the temperature of the sample is set and controlled by the heating element connected to a thermoregulator (Gefran-1000) equipped with a PT100 resistance thermometer, allowing to reach the set temperature with an accuracy of 2 • C. The use of the light guide is needed to preserve the PMT from overheating during operation, and a K-type thermocouple was set in close contact with the junction interface PMT glass/light guide to check the thermal conditions of the PMT during the acquisition time. The poly (methyl methacrylate) light guide material has a high decomposition temperature (around 330 • C) and its glass transition temperature is about 110 • C [23], thus it can be used without relevant decrease in optical and mechanical properties up to 120 • C. The heating rate cannot be controlled by the regulator, but it was manually set to avoid heat spikes on the sample at a rate of around 5 • C/min. Figure 1b The scintillation yield was estimated using 137 Cs γ source with the scintillator coupled to a light guide whose opposite side is facing the PMT: this allows to measure the light output as compared to a standard scintillator of the same size (EJ-299, Eljen Technology).…”

Section: Methodsmentioning

confidence: 99%

Temperature effects on light yield and pulse shape discrimination capability of siloxane based scintillators

et al. 2020

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In this work, we report the study of temperature effects on light yield of siloxane-based scintillators and on n/$$\gamma $$ γ discrimination capability, in terms of pulse shape discrimination (PSD). The solid scintillators are composed of phenyl containing polysiloxane (PMPS100), as a base polymer, loaded with moderate amounts (6 wt%) of 2,5-diphenyloxazole (PPO) as a primary dye and Lumogen Violet (LV) as waveshifter. The samples were heated in the range of 60–150 $$^\circ \hbox {C}$$ ∘ C and scintillation performance were tested both after annealing for 24 h and in real time during heating. Light yield of siloxane-based scintillators containing 6 wt% PPO heated at 100 $$^\circ \hbox {C}$$ ∘ C is very close to the room-temperature value, while heating at 120 $$^\circ \hbox {C}$$ ∘ C causes a decrease of light yield (LY) of 17%. In addition, the figure of merit (FoM) for n/$$\gamma $$ γ discrimination of the scintillator shows a sensible worsening of the discrimination performances in case of prolonged treatment at 120 $$^\circ \hbox {C}$$ ∘ C . Similar tests are made using the commercial plastic scintillator EJ-299 (currently named EJ-276), based on polyvinyltoluene (PVT). In this case, the light yield undergoes a much more rapid deterioration with annealing temperature, and at 70 $$^\circ \hbox {C}$$ ∘ C it is reduced to 60% of the original value. The discrimination capability of EJ-299 decreases upon heating at 70 $$^\circ \hbox {C}$$ ∘ C as well, with a 20% reduction of FoM; meanwhile for T > 70 $$^\circ \hbox {C}$$ ∘ C the mechanical and optical features are remarkably degraded. The mass loss of primary dye PPO from the siloxane scintillator as a function of treatment temperature and initial dye concentration has been evaluated and compared to the behaviour of EJ-299. This measurement allows to single out and characterize a series of processes occurring during heating, which are relevant to the whole performance of the system under study, such as sublimation at the interface, thermally induced photooxidation of components, diffusion of fluorophores from the polymer bulk to the surface. The variation in luminescence characteristics have been analyzed by excitation/fluorescence spectroscopy and time-resolved fluorescence spectroscopy, in order to correlate the annealing treatment with the primary dye loss by sublimation, formation of superficial aggregates and/or degradation of the scintillator components in the synthesized siloxane scintillator.

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Evaluation and Optimization of Erosion Parameters’ Effects on Polymeric Glasses Using Taguchi Method

Benterki,

Faci,

Barka

et al. 2023

J. of Materi Eng and Perform

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Heat treatment effect on erosion behavior of poly(methylmethacrylate) for optical transmittance efficiency

Cited by 4 publications

References 59 publications

A comparative study of heat-cured and gamma-cured fiber-reinforced denture-base acrylic resins: Residual monomer and flexural strength

A comparative study of heat-cured and gamma-cured fiber-reinforced denture-base acrylic resins: Residual monomer and flexural strength

Temperature effects on light yield and pulse shape discrimination capability of siloxane based scintillators

Evaluation and Optimization of Erosion Parameters’ Effects on Polymeric Glasses Using Taguchi Method

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