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Methyl Methacrylate Monomer (methyl + methacrylate_monomer)

Distribution by Scientific Domains
Polymers and Materials Science60%
Medical Sciences40%

Selected Abstracts

Effect of reline material and denture base surface treatment on the impact strength of a denture base acrylic resin

GERODONTOLOGY, Issue 1 2010
Luciano Elias Da Cruz Perez
doi:10.1111/j.1741-2358.2009.00292.x Effect of reline material and denture base surface treatment on the impact strength of a denture base acrylic resin Objective:, In this study, the effect of relining and surface treatment on the impact strength (IS) of a heat-polymerising denture base acrylic resin (Lucitone 550-L) was evaluated. Materials and methods:, Rectangular bars of L were made (60 × 6 × 2 mm) and relined (2 mm) with the relining resins Ufi Gel Hard (UH) and Tokuso Rebase Fast (TR). Specimens relined with L and intact L, TR and UH specimens were also made (60 × 6 × 4 mm), for comparison. Before relining, the L surface was left untreated or wetted with methyl methacrylate monomer and/or the bonding agents (BA) supplied by manufacturers of the reline resins. V-notches were machined at the midpoint of the length of all specimens. The notches were made either across the width (Nw) or across the thickness of the specimens (Nth). The Charpy impact test was performed using a 0.5-J pendulum, which had been specially designed and constructed. Data were analysed separately for each notch position using one-way analysis of variance and Tukey honestly significant difference post - hoc test (p = 0.05). Results:, The IS of L was similar to that of L/L. For the Nw notch, treating the denture base L with TR BA and relining with TR reline material produced the highest IS. Conclusion:, The IS of specimens made from heat polymerising acrylic resin Lucitone 550 was increased after relining using the hard chairside reline resin TR with its proprietary BA. [source]

Bonding strength between a hard chairside reline resin and a denture base material as influenced by surface treatment

JOURNAL OF ORAL REHABILITATION, Issue 12 2001
C. R. Leles
Direct relining of dentures made with hard chairside reline resins is faster than laboratory-processed reline systems and the patient is not without the prosthesis for the time necessary to perform the laboratory procedures. However, a weak bond between the autopolymerizing acrylic reline resins and the denture base material has been observed. This study evaluated the effect of six different surface treatments on the bond strength between a hard chairside reline acrylic resin and a heat-cured acrylic resin. Specimens of the heat-cured acrylic resin were divided into seven groups. One of these groups remained intact. In the other groups, a 10-mm square section was removed from the centre of each specimen. The bonding surfaces were then treated with (i) methyl methacrylate monomer, (ii) isobutyl methacrylate monomer, (iii) chloroform, (iv) acetone, (v) experimental adhesive and (vi) no surface treatment , control group. Kooliner acrylic resin was packed into the square sections and polymerized. The bonding strength was evaluated by a three-point loading test. The results were submitted to one-way analysis of variance (ANOVA) followed by a Tukey multiple range test at a 5% level of significance. No significant difference was found between the surface treatment with Lucitone 550 monomer or chloroform, but both were stronger than the majority of the other groups. The bond strength provided by all the surface treatments was lower than that of the intact heat-cured resin. [source]

Characterization of Methyl Methacrylate Grafting onto Preirradiated Biodegradable Lignocellulose Fiber by , -Radiation

MACROMOLECULAR BIOSCIENCE, Issue 1 2005
Ferdous Khan
Abstract Summary: Gamma-radiation-induced graft copolymerization of methyl methacrylate onto natural lignocellulose (jute) fiber was carried out by the preirradiation method in an aqueous medium by using octylphenoxy-polyethoxyethanol as an emulsifier. The different factors that influenced the graft copolymer reaction process were investigated. In the case of radiation-dose-dependent grafting, samples irradiated in the presence of air produced up to 73% graft weight compared to 53% obtained in the case of irradiation in a nitrogen environment. By assuming Arrhenius reaction kinetics, the activation energy (Ea) of the grafting reaction process was evaluated for different reaction temperatures. Moreover, the graft copolymer reaction was controlled by incorporating a homopolymer-inhibiting agent and three different chain-transfer agents in the reaction medium. The mechanical and thermal properties of jute fiber ,as received' and jute- graft -poly(methyl methacrylate) were also investigated. The results showed that the percentage of grafting with jute fiber has a significant effect on the properties. The kinetic parameters were evaluated from TGA thermograms by using Broido's method in the temperature range 240,350,°C. Scanning electron micrographs show that the structural changes on the surface of jute fibers were induced by graft copolymerization of methyl methacrylate monomer. Fiber-fiber surface friction was measured in terms of the average maximum load and the kinetic friction. SEM of jute- graft -poly(methyl methacrylate). [source]

Effect of clay with different cation exchange capacity on the morphology and properties of poly(methyl methacrylate)/clay nanocomposites

POLYMER COMPOSITES, Issue 11 2009
Tsung-Yen Tsai
PMMA/clay nanocomposites were successfully prepared by in situ free-radical polymerization with the organic modified MMT-clay using methyl methacrylate monomer and benzoyl peroxide initiator. Two clays with different cation exchange capacity have been used to prepare and compare the several properties. The clays have been modified using Amphoterge K2 by ion exchange reaction to increase the compatibility between the clay and polymer matrices. The modified clays have been characterized by wide-angle X-ray diffraction pattern, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA). The powdered X-ray diffraction and transmission electron microscopy techniques were employed to study the morphology of the PMMA/clay nanocomposites which indicate that the modified clays are dispersed in PMMA matrix to form both exfoliated and intercalated PMMA/modified clay nanocomposites. The thermomechanical properties were examined by TGA, differential scanning calorimetry, and dynamic mechanical analysis. Gas permeability analyzer shows the excellent gas barrier property of the nanocomposites, which is in good agreement with the morphology. The optical property was measured by UV,vis spectroscopy which shows that these materials have good optical clarity and UV resistance. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source]

Diffusion-Controlled Particle Growth and its Effects on Nucleation in Stirred Emulsion Polymerisation Reactors

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 8 2004
Shahriar Sajjadi
Abstract Summary: Particle formation and growth in the batch emulsion homo-polymerisation of styrene and methyl methacrylate monomers under diffusion-controlled conditions were studied. The polymerisations started with two stratified layers of a monomer and water containing an initiator and a surfactant, with the water layer being gently stirred. Because of limitations in monomer transport, the rate of particle growth was substantially reduced and as a result a large number of polymer particles formed. Schematic presentation of the highly diffusion-controlled polymerisation. [source]