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Acrylic Monomers (acrylic + monomer)
Selected AbstractsCharacterization of new acrylic bone cements prepared with oleic acid derivativesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2002Blanca Vázquez Abstract Acrylic bone-cement formulations were prepared with the use of a new tertiary aromatic amine derived from oleic acid, and also by incorporating an acrylic monomer derived from the same acid with the aim of reducing the leaching of toxic residuals and improving mechanical properties. 4-N,N dimethylaminobenzyl oleate (DMAO) was used as an activator in the benzoyl-peroxide radical cold curing of polymethyl methacrylate. Cements that contained DMAO exhibited much lower polymerization exotherm values, ranging between 55 and 62 °C, with a setting time around 16,17 min, depending on the amine/BPO molar ratio of the formulation. On curing a commercial bone cement, Palacos® R with DMAO, a decrease of 20 °C in peak temperature and an increase in setting time of 7 min were obtained, the curing parameters remaining well within limits permitted by the standards. In a second stage, partial substitution of MMA by oleyloxyethyl methacrylate (OMA) in the acrylic formulations was performed, the polymerization being initiated with the DMAO/BPO redox system. These formulations exhibited longer setting times and lower peak temperatures with respect to those based on PMMA. The glass transition temperature of the experimental cements were lower than that of PMMA cement because of the presence of long aliphatic chains of both activator and monomer in the cement matrix. Number average molecular weights of the cured cements were in the range of 1.2×105. PMMA cements cured with DMAO/BPO revealed a significant (p<0.001) increase in the strain to failure and a significant (p<0.001) decrease in Young's modulus in comparison to Palacos® R, whereas ultimate tensile strength remained unchanged. When the monomer OMA was incorporated, low concentrations of OMA provided a significant increase in tensile strength and elastic modulus without impairing the strain to failure. The results demonstrate that the experimental cements based on DMAO and OMA have excellent promise for use as orthopaedic and/or dental grouting materials. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 88,97, 2002; DOI 10.1002/jbm.10092 [source] Allergic contact stomatitis caused by acrylic monomer in a dentureAUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 3 2001Dennis Koutis SUMMARY A 71-year-old edentulous man developed a severely painful red mouth at sites of contact with a new denture. Patch testing showed allergy to samples of the denture material and to 2-hydroxyethyl methacrylate. Patch testing to methyl methacrylate was negative. Prolonged boiling of the denture resulted in reversal of his symptoms and samples of this fully cured denture material produced negative patch tests. While allergy to acrylates is a rare cause of stomatitis, this possibility must be considered in patients presenting with oral symptoms. Material safety data sheets are unreliable in providing information regarding the type of acrylate present in the material. Hence, patch testing should be performed with a battery of acrylate allergens as well as with small samples of the denture material. [source] Polyurethane/acrylate hybrids: Effects of the acrylic content and thermal treatment on the polymer propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Pablo J. Peruzzo Abstract Polyurethane (PU)/acrylate hybrids with different acrylic contents (10, 30, 50, 70, and 90 wt %) were prepared by the polymerization of acrylic monomers in the presence of preformed PU chains with polymerizable terminal vinyl groups. Films obtained by the casting of polymer dispersions before and after thermal annealing were characterized by dynamic light scattering, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), TEM electron energy-loss spectroscopy, differential scanning calorimetry, and gel fraction determination. Small-angle X-ray scattering (SAXS), wide-angle X-ray scattering, mechanical properties testing, atomic force microscopy, water contact angle testing, Buchholz hardness testing, and roughness testing of the films were also performed. The effects of the acrylic content and thermal treatment on the structure and properties were determined. TEM showed that a core,shell morphology was formed during polymerization. When the acrylic content increased, smaller particles without core,shell morphologies were observed. TEM energy-loss spectroscopy studies confirmed this observation. Systems with up to 50 wt % acrylic component were homogeneous, as determined by SAXS, before and after thermal annealing. An attempt to incorporate a higher amount of acrylic component led to phase-separated materials with a different morphology and, therefore, different properties. The relationship between the acrylic content and properties did not follow linear behavior. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Effect of molecular relaxation of acrylic elastomers on impact toughening of polybutylene terephthlateJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007Nafih Mekhilef Abstract In this study, we examined the performance of two core-shell acrylic-based impact modifiers (AIM) prepared by emulsion polymerization. The rubber core was prepared from ethyl hexyl acrylate (EHA) and n -octyl acrylate (n -OA). In such as process, the particle size and particle-size distribution of the modifiers were precisely controlled, so that performance differences observed in polybutylene terephthlate (PBT), used as matrix resin, could only be interpreted in terms of the nature of the elastomeric component of the modifiers. When isolated, the rubber core of the modifiers showed identical glass transition temperatures (Tg) by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) despite the fact that they were made from two different acrylic monomers. Temperature-frequency superposition principle inferred from the classical WLF equation showed that the rubber components exhibit the same Tg at all frequencies including at the time scale at which mechanical impact typically occurs. However, significant differences in low temperature impact performance measured at ,30°C using notched Izod impact test according to ASTM D 256 were obtained even though their rubber components had identical Tg. Such differences were attributed to the dynamic relaxation behavior of the rubber components and identified as inherent properties of the elastomers due to the structure of the monomers' repeat units. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Emulsion polymerization: From fundamental mechanisms to process developmentsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2004José M. Asua Abstract Emulsion polymers are "products by process" whose main properties are determined during polymerization. In this scenario of margins reduction, increasing competition, and public sensitivity to environmental issues, the challenge is to achieve an efficient production of high-quality materials in a consistent, safe, and environmentally friendly way. This highlight reviews the investigations carried out at The University of the Basque Country to develop a knowledge-based strategy to achieve these goals. First, the research in fundamental mechanisms is discussed. This includes studies in radical entry and exit, oil-soluble initiators, propagation-rate constants of acrylic monomers, processes involved in the formation of branched and crosslinked polymers, microstructure modification by postreaction operations, the formation of particle morphology, and reactive surfactants. The advanced mathematical models developed in the group are also reviewed. In the second part, the advances in process development (optimization, online monitoring and control, monomer removal, production of high-solids, low-viscosity latices, and process intensification) are presented. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1025,1041, 2004 [source] Frontal polymerization of acrylic monomers for the consolidation of stonePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 4 2005Silvia Vicini Abstract Polymeric products are largely used for consolidation of stone in the field of cultural heritage. Nevertheless, the main problem of polymeric compounds is related to their macromolecular nature, it being difficult for a polymer to penetrate inside the pores which may have a very small diameter. These considerations are the starting points for in situ polymerization. According to this technique, not the pre-formed polymer, but the monomer is introduced into the stone and it is polymerized in situ in a subsequent step. Frontal polymerization (FP) is a particular technique in which the heat released by the exothermal reaction of monomer to polymer conversion is exploited to promote the formation of a hot traveling front able to propagate and self-sustain the reaction. In the present work, FP is performed inside the pores of the stone and the results lead to the conclusion that the hot front is still active in the presence of an inorganic material which dissipates partially the heat released during the polymerization. In addition some recent applications of FP are discussed in comparison with the traditional polymerization for the in situ consolidation and protection of stones. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||