Acrylic Medium Research Articles

Effect of 0.2% peracetic acid disinfection on the horizontal dimension of implant framework indexed with two autopolymerized acrylic resins

BackgroundTo minimize misfit between prosthesis and implant, the welding of the implant fixed partial denture (IFPD) framework is recommended and autopolymerized acrylic resin (AR) is the material of choice for the indexing process. As for any prosthetic device that comes into contact with saliva and blood in the oral cavity, IFPD indexed with AR must be disinfected before sending to the laboratory. However, disinfection procedures are often neglected for fear of shrinkage or distortion caused by a dimensional change of the acrylic resin. Peracetic acid is a high-level disinfectant agent at low concentrations and immersion time, with no reported toxic residues, and it is not inactivated in the presence of organic matter when compared to other disinfectants. This study aimed to evaluate the influence of 0.2% peracetic acid disinfectant solution after different storage media and times on the horizontal dimension of IFPD frameworks indexed with AR.Material and methodsIFPD frameworks were indexed with two AR: group 1 Duralay and group 2 Pattern Resin LS. Each group was further divided into five subgroups according to disinfection procedure and storage medium: no disinfection and dry storage, no disinfection and water storage, 0.2% peracetic acid disinfection and water storage, 0.2% peracetic acid disinfection and peracetic acid storage, and 0.2% peracetic acid disinfection and dry storage. The horizontal dimension of the specimens and an average was established for analysis. Measurements were performed at four different storage times (hours): T0, T24, T48, T168.ResultsNo statistical differences were found when T0 was compared to T168 for Pattern resin groups submitted to disinfection and storage in water (group 2b, p = 1.000) or peracetic acid solution (group 2c, p = 0.352). For Duralay groups, the use of peracetic acid solution did not affect the horizontal dimension of the specimens when T0 was compared to T168 only with water as a storage medium (group 1b, p = 1.000). Additionally, T0 did not differ from T24 for groups 1c (p = 0.553), 2b (p = 1.000), 2d (p = 0.234), and 2e (p = 1.000) and from T48 for groups 1d (p = 0.118) and 2b (p = 1.000).ConclusionWithin the studied conditions, the use of 0.2% peracetic acid can be safely used as a disinfectant solution regarding dimensional stability of AR-indexed IFPD until 7 days of storage. Horizontal discrepancies are dependent on acrylic resin type, time, and medium of storage.

Pigment Synthesis for the Exploration of Binding Media Using a Lead-Free Alternative to Chrome Yellow

Generating enthusiasm among nonscience majors in a laboratory course is a difficult task. Often, students are asked to perform a precipitation reaction, only to collect and then safely dispose of the solid without detailing composition, properties, or uses. In an effort to keep the students engaged, this laboratory exercise presents an innovative way to use the product of a precipitation reaction. The reaction chosen produces basic zinc(II) chromate, a yellow pigment that can be combined with various paint binders such as beeswax, gum Arabic, egg yolk, linseed oil, and acrylic medium. The students then test their paints on a canvas and analyze their different physical properties. This exercise can be tailored to match different undergraduate levels, ranging from nonscience majors to chemistry majors and be used as a part of a STEAM (science, technology, engineering, arts, and mathematics) activity. A brief discussion on historical paint binders and their chemistry is also included.

Ontological pivots

This article provides a survey of recent projects in the acrylic medium, detailing some of the operative conceptual machinery and genesis of the ideas, with brief reflections on the implications of materials, process and aesthetic choices. It attempts to extract speculative philosophical consequences for approaches to drawing and the possibilities of thinking its act through the concepts of gesture and manipulative abduction as they appear in the work of Gilles Châtelet and Lorenzo Magnani, respectively. Beyond this, the article sets up a potential task for thinking art in relation to alienation and estrangement as ineradicable aspects of its procedures, and considers them as liberating rather than constricting mechanisms.

Acrylic protective coatings modified with titanium dioxide nanoparticles: Comparative study of stability under irradiation

Acrylic coatings based on Paraloid B72 were modified with different types of titanium dioxide nanoparticles to obtain transparent, non-yellowing and chemically stable coatings, having also self-cleaning properties. To finely disperse the inorganic nanoparticles in the polymer matrix two strategies were followed: i) ex-situ functionalization of nanoparticles and ii) use of organic–inorganic coupling agents. Characterization focussed especially on the photooxidative stability of TiO2 modified coatings. This is actually one of the most critical aspects of organic materials containing photoactive nanoparticles. The highly oxidant environment produced on the catalyst surface by photogenerated species is capable to mineralize many organic compounds, but in a poorly selective way, and this often undermines the stability of the polymer that binds the photocatalyst. Improved dispersability of TiO2 nanoparticles generally resulted in a diminished chemical stability of the acrylic medium, but by using tetraethoxysilane (TEOS) as a coupling agent, oxidation and cross-linking reactions were considerably reduced, ensuring better stability and reversibility in comparison to Paraloid coatings containing photoactive TiO2 nanoparticles without TEOS.

Fabrication and full characterization of state-of-the-art quantum dot luminescent solar concentrators

The fabrication and full characterization of luminescent solar concentrators (LSCs) comprising CdSe core/multishell quantum dots (QDs) is reported. TEM analysis shows that the QDs are well dispersed in the acrylic medium while maintaining a high quantum yield of 45%, resulting in highly transparent and luminescent polymer plates. A detailed optical analysis of the QD-LSCs including absorption, emission, and time-resolved fluorescence measurements is presented. Both silicon and GaAs solar cells attached to the side of the QD-LSCs are used to measure the external quantum efficiency and power conversion efficiency (2.8%) of the devices. Stability tests show only a minor decrease of 4% in photocurrent upon an equivalent of three months outdoor illumination. The optical data are used as input for a ray-trace model that is shown to describe the properties of the QD-LSCs well. The model was then used to extrapolate the properties of the small test devices to predict the power conversion efficiency of a 50×50 cm 2 module with a variety of different solar cells. The work described here gives a detailed insight into the promise of QD-based LSCs.

Development of MALDI-MS and nano-ESI-MS methodology for the full identification of poly(ethylene glycol) additives in artists’ acrylic paints

An analytical mass spectrometric method was developed for the comprehensive characterization of the poly(ethylene glycol) (PEG) based additives present in water extracts of acrylic emulsions, acrylic emulsion paints and samples from paintings. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used to determine the molar mass distribution (MMD), i.e., the weight average molar mass, number average molar mass and the polydispersity characteristics of the PEG compounds. Nano electrospray ionisation mass spectrometry (ESI-MS) was used to determine the end-group structures. It was possible to determine both end-groups of the PEG compounds using ESI-MS in combination with nozzle skimmer dissociation (NSD) and tandem MS (MSMS). The method development is part of a larger project of analysis of artists’ paints and samples from paintings reported elsewhere. The new methodology is demonstrated here with two relevant examples of a often used PEG and an acrylic medium.

Studies of organic paint binders by NMR spectroscopy

Nuclear magnetic resonance spectroscopy is applied to the study of aged binding media used in paintings, namely linseed oil, egg tempera and an acrylic medium. High resolution 1D and 2D NMR experiments establish the state of hydrolysis and oxidation of the linseed and egg tempera binders after five years of aging, by determining several markers sensitive to the hydrolytic and oxidative processes of the binder lipid fraction. The composition of the acrylic binder co-polymer is determined by 2D NMR spectroscopy, while the identification of a surfactant, poly(ethylene glycol), found in greater amounts in aged acrylic medium, is reported.

Characterization of Artists' Acrylic Emulsion Paints

Commercial waterborne acrylic artists' paints have been characterized with pyrolysis - GC - MS, NMR, size exclusion chromatography and FTIR, and thermogravimetry, for establishing chemical composition, solubility behavior, presence of fillers and additives. In all the pigmented formulations, and in one pure medium, the polymeric base has been invariably found to be formed by different amounts of an ethyl acrylate - methyl methacrylate copolymer. A second acrylic medium revealed the presence of \\rm n -butyl acrylate as a third monomer. Pigmented paints were always more difficult to dissolve than pure media, and the occurrence of insoluble material could be demonstrated with titanium white paints. Inorganic components and other additives present in the paint formulations are expected to have some influence on the chemical and molecular evolution of the paints with aging.

The Light Bleaching of Discolored Films of an Acrylic Artists' Medium

The Light Bleaching of Discolored Films of an Acrylic Artists' Medium

Study of fire retardancy and thermal stability of vinyl acetate-2-ethylhexyl acrylate copolymer by blending with amino resin in aqueous medium

Trimethoxymethyl melamine (TMMM) and hexamethoxymethyl melamine (HMMM) were blended with the widely used acrylic medium, the copolymer of vinyl acetate and 2-ethylhexyl acrylate (VAc-EHA), for preparing water-based blends having improved fire retardancy. The weight fraction of the VAc-EHA copolymer was varied from 40 to 95%, at the pH value of 7 and a solid content of 50% was kept in all cases. The limiting oxygen index (LOI) and char yield of the blends were evaluated and the surface morphology of TMMM, HMMM, and the VAc-EHA copolymer at room temperature and at 110, 340, and 550°C was also studied to explain the improvement in the fire-retardancy behavior of the blends. The LOI and char yield of the VAc-EHA copolymer was found to improve substantially on incorporation of both TMMM and HMMM. But due to the limited stability of TMMM in aqueous medium, HMMM is more suitable for blending with VAc-EHA, to give a water-based coating having good fire-retardancy properties. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 985–990, 1997

Conservation of the Darnault Mirror: An Acrylic Emulsion Compensation System

AbstractA 1751 French boiserie mirror, which retained approximately 30% of its original gilding, was treated at the J. Paul Getty Museum. In the initial phase of the treatment, the mirror frame was thoroughly analyzed, its condition was documented, and testing of possible cleaning and compensation methods was begun. Ultimately, the conservators were not pleased with the results of that work, which was presented in a paper at the AIC Annual Meeting in 1994. Re-evaluation of the treatment led to the use of new materials for a barrier coat and for compensation of the losses in the gilding, including acrylic emulsion medium, mica pigments, and gold leaf. In creating the alternative system, the conservators and curators aimed to maintain the original goals of the project, including the proper interpretation and display of the mirror in the galleries as well as preservation of the physical integrity of the object. Methods for using nontraditional materials in a manner complementary to the original materials wer...