SEARCH · Search PubMed

Results for “Methacrylates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources

PubMed1987

Polymerization shrinkage of methacrylate esters.

The polymerization shrinkage of a range of poly(n-alkyl methacrylates) in the range C1 to C16, some of their isomers and the polymers of cyclic and heterocyclic methacrylates have been measured using densitometry. The percentage volume shrinkage decreases with the size of the substituent side group. This proved to reflect the fact that the change in molar volume on polymerizing a methacrylate ester is reasonably constant at 22 cc/mol irrespective of the geometry of the substituent group. However, the glass transition temperature of the polymer depends very critically on the geometry of the side group. Hence one method for the development of low shrinkage glassy polymers is to investigate methacrylate esters of large molar volume, but with side group geometry that results in a high glass transition temperature. Polymerization shrinkage can be used to determine the degree of conversion of a polymer, using the value of 22 cc/mol as the change in molar volume.

Acrylates↗

PubMed1995

Blood perfusion and remodelling activity in canine tibial diaphysis after filling with a new bone cement compared to bone wax and poly(methyl methacrylate) cement.

Six dogs each had one tibia filled with standard poly(methyl methacrylate) (PMMA) bone cement and the contralateral tibia filled with a new methyl methacrylate-n-decyl methacrylate-isobornyl methacrylate (MMA-DMA-IBMA) bone cement (Boneloc) with lowered polymerization heat and monomer leakage. An additional six dogs each had one tibia filled with MMA-DMA-IBMA and the contralateral tibia filled with bone wax. There was a higher diaphyseal blood flow, measured with a microsphere technique, in the legs filled with MMA-DMA-IBMA than in those filled with PMMA. The wax-filled bones presented higher blood perfusion than those with MMA-DMA-IBMA. We found a tendency towards higher 99mtechnetium-labelled methylene diphosphonate (99mTcMDP) uptake, and autoradiograms revealed a tendency towards larger subperiosteal apposition and more blackening, both at the subperiosteal apposition and the cortex, in the bones filled with new bone cement in the first series, but in wax-filled bone in the second series. It is concluded that the new bone cement, compared to standard acrylic bone cement, seems to inhibit the vascular response and bone remodelling activity less, making earlier remodelling possible. However, the new bone cement still seems to inhibit bone blood perfusion compared to bone wax.

Animals↗

PubMed1982

Structure-toxicity relationship of acrylates and methacrylates.

The structure-toxicity relationships of acrylates and methacrylates were analysed in mice. In all test compounds, the acute oral toxicity (LD), the partition coefficient (P), and the second order rate constant (K) with reduced glutathione were measured experimentally. The toxicities of both acrylates and methacrylates were found to be dependent significantly upon log P or log K, especially upon the former. The correlation coefficient between log (1/LD50) and log P, was -0.9909 for acrylates and -0.795 for methacrylates, both being statistically significant. The correlation coefficient between log P and log K was -0.935 for acrylates and -0.744 for methacrylates.

Acrylates↗

PubMed2005

Comparative study on the properties of acrylic bone cements prepared with either aliphatic or aromatic functionalized methacrylates.

Bone cements prepared with methacrylic acid (MAA) and diethyl amino ethyl methacrylate (DEAEM) were compared with formulations employing 4-methacryloyloxybenzoic acid (MBA) and 4-diethyaminobenzyl methacrylate (DEABM) as comonomer. The influence of these new aromatic monomers on various physicochemical, setting and mechanical properties was assessed. Surface characterization demonstrated that bone cements prepared with any of the functionalized monomers exhibited increasing hydrophilicity with monomer concentration and that the aromatic monomers provided more hydrophilic cements than their aliphatic counterparts for low concentrations of the functional monomer. It was also found that bone cements prepared with high amounts of the acidic aliphatic monomer provided the highest exotherm of reaction and their setting times were shorter than MBA based cements. On the other hand, DEABM containing bone cements exhibited shorter setting times than DEAEM formulations and slightly higher peak temperatures. In general, it was found that the glass transition temperature increased with the presence of acidic comonomer and decreased when alkaline comonomers were present, especially aliphatic ones. When aromatic methacrylates were used at 0.05 molar fraction, the highest tensile and compressive strength were achieved i.e. 46 and 118 MPa for MBA and 51 and 108 MPa for DEABM formulations. A further increase in the aromatic monomer concentration led to cements of low mechanical properties due to solubility problems as revealed by SEM.

Benzoates↗

PubMed2006

Design, synthesis, and in vivo evaluation of oxamniquine methacrylate and acrylamide prodrugs.

Oxamniquine is an antiparasitic agent commonly used in therapeutics against Schistosoma mansoni. Although it is well tolerated, some adverse effects justify the search for new compounds with prolonged biological action, so that monomeric and polymeric oxamniquine prodrugs were designed. Synthetic results assisted by molecular modeling study showed the possibility to obtain the corresponding monomeric forms of the oxamniquine methacrylate (1) and oxamniquine acrylamide (2). Successful copolymerization procedure only occurred on the methacrylic compound, generating the oxamniquine methacrylate copolymer (3). Submitted to a preliminary in vivo biological evaluation, a similar oxamniquine profile was observed to the monomeric forms although an inadequate drug release may be responsible for the methacrylic copolymer failure.

Acrylamide↗

PubMed2003

Synthesis and characterization of hydrogels formed from a glycidyl methacrylate derivative of galactomannan.

The present investigation describes a procedure for the synthesis of a glycidyl methacrylated derivative from galactomannan, GA-MA, and the respective hydrogel formation. The galactomannan (GA), raw material, was purified and dissolved in DMSO. After dissolution, 4-dimethyl-amino-pyridine (DMAP) and glycidyl methacrylate (GMA) were added. The modified polymer, quoted as GA-MA, was purified by precipitation in ethanol. Hydrogels were obtained from GA-MA in aqueous solution by polymerization of GA-MA using sodium persulfate (SP), as initiator, and N,N,N',N'-tetramethylethylenediamine (TEMED), as catalyst. For this, the cross-linking process was trigged by the addition of TEMED and sodium persulfate aqueous solutions. Two different concentrations of TEMED and SP were used. GA, GMA and GA-MA were characterized by FT-IR and NMR (13C and 1H) spectroscopy. The addition of GMA on GA molecules was confirmed through FT-IR results by appearing of a band at nu=1717cm(-1) and also by the cleavage of Cz.dbnd6;C groups of GA-MA (band at nu=1636cm(-1)) during the cross-linking process. The signals attributed to vinyl carbon of methacrylate (delta 138.52, 130.06ppm), to carbonyl (delta 171.87ppm) and to methyl group (delta 20.19ppm) were observed in the 13C NMR spectra of GA-MA. The addition of methacrylate on GA was also confirmed through the signals present in 1H NMR spectra of GA-MA. The formation of hydrogel was observed by complete gelation. The hydrogels were characterized by FT-IR and by measuring the equilibrium water content (EWC) in pH=7.0 and 1.0. The hydrogels contain 83wt.% of water at 25 degrees C and 85wt.% at 37 degrees C. Good resistance to degradation in acidic conditions, pH=1.0, was observed at 37 degrees C up to 48h. These properties suggest that the GA-MA hydrogels may be a new material for pharmaceutical use, mainly for drug delivery system.

Chromatography, High Pressure Liquid↗

PubMed2004

Magnetic hydrophilic methacrylate-based polymer microspheres designed for polymerase chain reactions applications.

Magnetic hydrophilic non-porous P(HEMA-co-EDMA), P(HEMA-co-GMA) and PGMA microspheres were prepared by dispersion (co)polymerization of 2-hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA) or glycidyl methacrylate (GMA) in the presence of several kinds of magnetite. It was found that some components used in the preparation of magnetic carriers interfered with polymerase chain reaction (PCR). Influence of non-magnetic and magnetic microspheres, including magnetite nanoparticles and various components used in their synthesis, on the PCR course was thus investigated. DNA isolated from bacterial cells of Bifidobacterium longum was used in PCR evaluation of non-interfering magnetic microspheres. The method enabled verification of the incorporation of magnetite nanoparticles in the particular methacrylate-based polymer microspheres and evaluation of suitability of their application in PCR. Preferably, electrostatically stabilized colloidal magnetite (ferrofluid) should be used in the design of new magnetic methacrylate-based microspheres by dispersion polymerization.

Bifidobacterium↗

PubMed2006

Physical properties of a new denture lining material containing a fluoroalkyl methacrylate polymer.

STATEMENT OF PROBLEM: A new fluoride-containing, methacrylate-based denture lining material has been introduced. Because of the fluoride content, this material is expected to demonstrate low water sorption and solubility and high stain resistance, but these attributes remain untested. PURPOSE: This study investigated a wide range of clinically relevant properties for a new fluoroalkyl methacrylate denture base liner product (Maxfit) and compared these properties with those of 3 other commercial products. MATERIAL AND METHODS: Four denture lining materials were tested: Maxfit, Kooliner, Tokuyama Rebase (fast set), and Denture Liner. Water sorption (microg/mm(3)) and solubility (microg/mm(3)) were tested according to International Organization for Standardization (ISO) Standard No. 1567. Stain resistance was evaluated by measuring color change (DeltaE) after immersion in 2 solutions (coffee and turmeric solution). Microhardness was determined using Knoop indentation testing according to American National Standards Institute/American Dental Association Specification No. 17. Relined denture fit was evaluated by measuring the gap (mm) occurring between the relined denture base and the cast after polymerization. Shear bond strength (MPa) to denture base materials (polymethyl methacrylate, cobalt-chromium alloy, and titanium) was tested according to ISO Standard No. 11405. Data were statistically analyzed using nonparametric Kruskal-Wallis (alpha=.05) and Mann-Whitney U tests combined with the Bonferroni correction (alpha=.008). RESULTS: Maxfit showed the lowest water sorption and solubility (8.0 +/- 0.1, 0.5 +/- 0.1 microg/mm(3), respectively). The color change from coffee immersion of Maxfit was significantly less than Tokuyama Rebase and Denture Liner, and significantly less than Tokuyama Rebase and Denture Liner in a turmeric solution (P<.001). Knoop hardness of Maxfit (8.66 +/- 0.51) was higher than Kooliner and Tokuyama Rebase (P<.001). The relined denture fit using Maxfit was not different from other materials. Significantly higher shear bond strength to denture base resin was noted for Maxfit compared to Tokuyama Rebase and Denture Liner (P<.008). CONCLUSIONS: The new fluoroalkyl methacrylate-based denture liner (Maxfit) showed the lowest water sorption and solubility, and superior stain resistance. In spite of the addition of the fluoride content, this product exhibited no deterioration in physical properties, such as surface hardness, fit of the relined denture, and shear bond strengths to denture base materials tested.

Adhesiveness↗

PubMed1975

Analysis and purification of 2-hydroxyethyl methacrylate by means of thin-layer chromatography.

Poly(2-hydroxyethyl methacrylate) is nowadays accepted as a biocompatible, safe and stable hydrogel for medical use. In this paper, the use of thin-layer chromatography for the analysis and small-scale preparation of the initial monomer, 2-hydroxyethyl methacrylate, is described. Development on silica gel, with n-hexane-diethyl ether (1:1, v/v) and/or n-hexane-isobutyl methyl ketone-n-octanol (9:2:1, v/v; saturated with 25% nitric acid) is recommended for qualitative analysis. Preparative-scale work is preferably carried out on sulphuric acid-impregnated silica gel, with n-hexane-diethyl ether (1:1, v/v) as mobile phase. Inhibitors are detected by thin-layer chromatography and a drop-test procedure with diazotised sulphanilic acid. The nature of the contaminants present in several commercial samples of 2-hydroxyethyl methacrylate is discussed. n20D values are reported for the system 2-hydroxyethyl methacrylate-water.

Acrylates↗

PubMed2001

Release of recombinant human bone morphogenetic protein-2 from heterocyclic methacrylate polymer systems.

The release of recombinant human bone morphogenetic protein-2 (rhBMP-2) from three room temperature polymerising methacrylate systems has been studied. These all contained poly(ethyl methacrylate) powder, but the monomer liquids comprised, respectively, tetrahydrofurfuryl methacrylate (THFM), 90/10 THFM/hydroxyethyl methacrylate (HEMA), and 70/30 THFM/ HEMA. In all cases, rhBMP-2 was released, but the addition of 10% HEMA accelerated release (a nine-fold increase in diffusion coefficient); a further increase to 30% HEMA had no additional effect. For most of the release process, a diffusion process operated, although the early stages were not well defined. At the end of the 15 day period, the release, respectively, for the PEM/THFM, PEM:90/10 THFM/HEMA and PEM:70/30 THFM/HEMA systems was 596, 878 and 923 ng (i.e. up to 92% of the rhBMP-2 added).

Biocompatible Materials↗

PubMed2000

Chlorhexidine release from room temperature polymerising methacrylate systems.

A series of different methacrylate monomers (with either 1 or 2.5% dimethyl-p-toluidine, DMPT) was gelled with poly(ethyl methacrylate) powder (containing benzoyl peroxide) thus forming a room temperature curing system. When doped with 5.625% chlorhexidine diacetate the release from the tetrahydrofurfuryl methacrylate-based samples was considerably greater than that from other methacrylate monomers. This seems to be due to the formation of channels in the polymer. Nuclear magnetic resonance spectroscopy, of solutions that the samples were immersed in, showed chlorhexidine was indeed being released from the polymer. It also showed that doping the polymer with chlorhexidine hindered the polymerisation, resulting in a higher level of residual monomer and low molecular weight components being leached from the polymer. The DMPT also affected the polymerisation with greater leaching from the 2.5% DMPT sample.

Anti-Infective Agents, Local↗

PubMed1998

Biologically active polymers: synthesis and antimicrobial activity of modified glycidyl methacrylate polymers having a quaternary ammonium and phosphonium groups.

Polymers with antibacterial activity have been synthesized by chemical modification of poly(glycidyl methacrylate). The glycidyl methacrylate was polymerized by the free radical polymerization technique. The poly(glycidyl methacrylate) was hydrolyzed and was chloroacetylated using chloroacetyl chloride. The chloroacetylated product was modified to yield polymers with either quaternary ammonium or phosphonium salts. The antimicrobial activity of the modified glycidyl methacrylate polymers has been examined against a variety of test microorganisms by the cut plug and the viable cell counting methods using shake flask of ten times diluted nutrient broth medium. All three polymers obtained were inhibitory to the growth of Gram negative bacteria (Escherichia coli, Pseudomones aeruginosa, Shigella sp. and Salmonella typhae) and Gram positive bacteria (Bacillus subtilis and B. cereus) as well as the fungus (Trichophytun rubrum). It was found that the growth inhibitory effect varied according to the structure of the polymer and the composition of the active group and increased with increasing the concentration of the polymer. The tested polymers showed more antimicrobial activity against Gram negative bacteria and the fungus, whereas were less active against Gram positive bacteria.

Anti-Bacterial Agents↗

PubMed1997

Iodinated methacrylate copolymers as X-ray opaque denture base acrylics.

OBJECTIVES: The purpose of this study was to evaluate novel iodinated methacrylate copolymers as X-ray opaque denture base resins. METHODS: The synthesis of specific monomers and suspension copolymerization with methyl methacrylate to produce copolymer beads. The resulting beads were processed in an identical manner to standard PMMA to produce test-pieces for mechanical testing. RESULTS: Samples prepared from beads containing 25 wt% of the iodinated copolymer exhibited an X-ray opacity equivalent to that exhibited by a similar thickness of aluminium. Furthermore, the appearance and mechanical properties were comparable to standard PMMA, while thermal stability proved superior. CONCLUSION: These novel iodinated methacrylate monomers show promise not only as polymerizable additives to methyl methacrylate to produce an X-ray opaque denture base but also as thermally stable copolymerizable additives to other applications where X-ray opacity would be advantageous.

Contrast Media↗

PubMed1991

Neodymium:YAG laser damage to UV-absorbing poly(methyl methacrylate) and UV-absorbing MMA-HEMA-EGDMA polymer intraocular lens materials.

MemoryLenses and UV-poly(methyl methacrylate) intraocular lenses, which served as controls, were individually exposed to twenty 5 mJ shots of the Nd:YAG laser focused onto the posterior surface while placed in a sterile holder containing 5 ml of saline. The MemoryLens is a new foldable intraocular lens (IOL) manufactured from a polymer consisting of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), and ethylene glycol dimethyacrylate (EGDMA) with a UV absorber. Damage to the lenses was assessed by scanning electron microscopy. Cytotoxicity tests designed to detect potentially toxic substances released during laser damage were conducted with the saline solution by incubating it with mouse fibroblasts. Additional tests of the saline solution were conducted by high performance liquid chromatography and spectrophotometry. Damage induced by the Nd:YAG laser to the UV-poly(methyl methacrylate) IOLs was similar to that reported by other authors. Damage to the MemoryLens appeared less severe and showed no radial stress cracking. Cytotoxicity tests were negative for both types of IOLs. High performance liquid chromatography tests were negative for residual monomers (MMA, HEMA, EGDMA) and spectrophotometry did not reveal residual UV absorber.

Animals↗

PubMed1985

LC50 values for rats acutely exposed to vapors of acrylic and methacrylic acid esters.

Acute exposure studies were conducted using adult male Sprague-Dawley rats to obtain LC50/24 concentrations for the common esters of acrylic and methacrylic acids. The order of acute toxicity was determined to be methyl acrylate greater than ethyl acrylate greater than butyl acrylate greater than butyl methacrylate greater than methyl methacrylate greater than ethyl methacrylate. Four-hour daily exposures (excluding weekends) of young adult male rats to 110 ppm methyl acrylate in air over a period of 32 d failed to produce significant differences in body or tissue weights, blood chemistries, gross metabolic performance, and spontaneous small-intestinal motor activities when compared with a sham-exposed group.

Acrylates↗

PubMed2006

Biomechanical evaluation of vertebroplasty and kyphoplasty with polymethyl methacrylate or calcium phosphate cement under cyclic loading.

STUDY DESIGN: We developed a new method to simulating in vivo dynamic loading as closely as possible, which allows comparison of kyphoplasty and vertebroplasty, as well as augmentation materials. OBJECTIVE: Special interest was given to calcium phosphate cement, which might fail due to its brittleness. SUMMARY OF BACKGROUND DATA: Vertebroplasty and kyphoplasty are, with limitations, 2 promising alternative techniques to augment osteoporotic vertebrae with polymethyl methacrylate or calcium phosphate cements. However, little is known about the fatigue characteristics of the treated vertebrae under cyclic loading. METHODS: Twenty-four intact, osteoporotic bi-segmental human specimens were divided into 4 groups: (1) vertebroplasty with polymethyl methacrylate, (2) kyphoplasty with polymethyl methacrylate, (3) kyphoplasty with calcium phosphate cement, and (4) untreated control group. After augmentation of the middle vertebrae, all specimens underwent 100,000 cycles of eccentric loading during which the specimen revolved around its longitudinal axis. Pre-loading and post-loading radiographs, and subsidence measurements at different sites of the vertebrae were taken. The overall height was additionally determined every 20,000 cycles in the material testing machine. Finally, the specimens were cryosectioned to examine the cements. RESULTS: Loss of height progressed with strong individual differences in all groups, with an increasing number of load cycles up to median values of 2.8 mm for both augmented groups and 4.2 mm for the nonaugmented group. At the center of the upper endplate, subsidence in kyphoplasty was greater than in vertebroplasty, with little differences with respect to the kind of cement. The cryosections did not show any signs of fatigue in the polymethyl methacrylate, but small cracks were in the calcium phosphate. CONCLUSIONS: Vertebroplasty and kyphoplasty seem to be equivalent methods in strengthening osteoporotic vertebrae. However, these results cannot be transferred to the treatment of fractures with these methods. A "physiologic" loading situation was achieved by complex motion, including all combinations of flexion/extension with lateral bending during eccentric cyclic loading.

Aged↗

PubMed2000

In vitro release behavior of dextran-methacrylate hydrogels using doxorubicin and other model compounds.

In vitro drug release behavior of doxorubicin, Alizarin Red S, FITC-dextran from photocross-linked dextran-methacrylate hydrogel was studied. The effects of pH of media, degree of substitution (DS) of dextran-methacrylate hydrogel, and molecular weight of model compounds on their release profiles were investigated. Each model compound was successfully incorporated into dextran-methacrylate hydrogel matrix through photopolymerization of the hydrogel precursor. Delayed release of model compounds was observed with these hydrogels having a higher DS. Doxorubicin and Alizarin Red S showed pH-dependent release behavior because of the presence of ionizable groups in their structure. Different types of ionization of doxorubicin and Alizarin Red S resulted in more release into an acidic or alkaline media. As molecular weights of drugs increased, the total amount of released drug at the end of 240 hrs decreased significantly and reached a minimum level as the MW of drugs reached about 10,000. Release of these three model compounds followed simple Fickian diffusion at an early stage of release, i.e., cumulative release of model compounds was proportional to the square root of time. Dextran-methacrylate hydrogel effectively delayed and controlled the release of anticancer antibiotics, doxorubicin.

Acids↗

PubMed2005

Shear bond strength of Resilon to a methacrylate-based root canal sealer.

AIM: To evaluate the adhesive strength of Resilon to Next root canal sealant (Heraeus-Kulzer), a methacrylate-based root canal sealer, using a modified microshear bond testing design. METHODOLOGY: Flat Resilon surfaces of different roughnesses (smooth surface and surface roughness equivalent to 320-grit and 180-grit) were prepared by compression moulding for bonding to the sealer and compared with a composite control. The shear strength data were statistically analysed using Kruskal-Wallis one-way anova on ranks and Dunn's multiple comparison tests (alpha = 0.05). After shear testing, fractured specimens were examined using a field emission-scanning electron microscope for detailed analysis of the failure modes. RESULTS: The composite control exhibited significantly higher mean shear strength (7.62 MPa) that was 4.4-4.7 times those of the Resilon groups (1.64-1.74 MPa; P < 0.001). Increasing the surface roughness of the Resilon surface did not contribute to further improvement in shear bond strength for this methacrylate-based sealer (P > 0.05). Failure modes in the composite control were cohesive and mixed failures, while those in the Resilon groups were predominantly adhesive failures, with a small percentage of mixed failures. Ultrastructural evidence of phase separation of polymeric components could be identified in Resilon. Both intact, non deformed and plastically deformed Resilon surfaces could be observed in specimens that exhibited adhesive failures. CONCLUSION: The low shear strength of Resilon to a methacrylate-based sealer compared with a composite control suggests that the amount of dimethacrylate incorporated in this filled, polycaprolactone-based thermoplastic composite may not yet be optimized for effective chemical coupling to methacrylate resins.

Analysis of Variance↗