Barium Methacrylate Research Articles

Contribution of water to the initiation of solid state polymerization of acrylate and methacrylate salt hydrates

The role of the water of crystallization in the initiation of the solid-state polymerization of calcium acrylate and barium methacrylate hydrates has been investigated in terms of its physical and chemical involvement in the polymerization reaction. The dynamics of the water of crystallization was studied by infrared absorption on D2O hydrated salts in the presence of water vapor. The variation of the relative intensities of the OD and OH bands in the infrared spectra showed that a rapid exchange occurred between the water of crystallization and water in the atmosphere. ESR studies on D2O hydrated salts proved that radicals, produced from the water, contribute substantially to the initiation of the polymerization reaction.

X-ray microtomographic studies of novel radio-opaque polymeric materials for dental applications

Radio-opacity may be desirable for polymeric materials used in medical and dental applications. However, problems arise when radio opaque metallic salts are blended with polymer powders before polymerisation. A novel alternative approach is to use polymers in which the X-ray opaque element is chemically incorporated within the monomer unit. The present study investigates two potential materials, a barium methacrylate monomer which is a powder at room temperature and a tin methacrylate monomer which is liquid at room temperature, both then mixed with a methacrylate diluent. X-ray microtomography revealed that the powdered barium methacrylate material did not blend well and particles of high X-ray attenuation were formed. Whereas, X-ray microtomography images of the tin methacrylate material revealed that the mixture was completely homogenous. The possible application of these two materials as a pit and fissure sealant is described.

Microtox System, a New Approach to the Safety Evaluation of Medical Devices

Medical devices of both intra- and extra-corporeal applications may contain leachable toxicants that warrant routine testing using internationally recognized/practiced protocols. An in vitro Microtox system comprising a selected bioluminescence strain of bacteria-Photobacterium phosphorium which emits light as an end product of its respiration, is used to screen out toxicants from biomaterials/devices. A Microtox system was standardized and validated in our laboratory conditions. Our experiences with extract of pyrogenic cardiotomy reservoir, blood filter and systemically toxic (in mice) Barium methacrylate (monomer), and CIBA epoxy polymer materials established a positive correlation with Microtox system. Hence, the Microtox system gives adequate evidence as an alternative in vitro method to evaluate the toxicity of biomaterials and medical devices.

Thermally initiated oligomerization of metallic salts of methacrylic acid in solid state

Thermal oligomerization of metallic salts of methacrylic acid was investigated over the temperature range 150°–240°C in the solid state. Calcium methacrylate gave α-methylene-γ, γ-dimethylglutarate(I) and α-methylene-δ-methyladipate(II) below 190°C, but I was not formed above 210°C. Above 170°C the trimer, 1-nonene-2,5,8-tricarboxylate(IV), was formed. Barium methacrylate gave both I and II above 170°C, and 4-methyl-1-octene-2,4,7-tricarboxylate(III) and IV above 190°C. Due to the oligomer crystals from calcium methacrylate were disordered, but crystals from barium methacrylate were transformed to the oligomer crystal lattice, I was formed not in the amorphous state but in the crystalline state, however, II was formed in both states. From these results the mechanism of the oligomer formation in the solid state was discussed.

Radiation‐induced, solid‐state polymerization of derivatives of methacrylic acid, 10. Polymerizability of barium methacrylate anhydrate

AbstractWhereas the radiation‐induced polymerization of crystalline barium methacrylate monohydrate has been well established there have been conflicting reports concerning barium methacrylate anhydrate. We have now shown that the yields of high molecular weight polymer are negligible if adequate precautions are taken to prevent polymerization occurring during the separation of polymer from residual monomer. However, monomer losses of up to 80% have been observed by titration of CC bonds with bromine and confirmed by decreases in the appropriate infrared absorptions. X‐ray diffraction studies showed that the crystalline lattice was largely destroyed during the reaction. ESR spectra indicate that initial trapped radicals are converted into propagating radicals with a different conformation than has been reported for the monohydrate.

Radiation-induced, solid-state polymerization of derivatives of methacrylic acid. IX. Electron spin resonance and product analysis study of the gamma radiolysis of methacrylic acid, barium methacrylate and their saturated analogues, isobutyric acid and barium isobutyrate

Methacrylic acid and barium methacrylate polymerize in the solid state during and after gamma irradiation. Previous ESR studies have indicated a free radical chain mechanism initiated by radical, particularly H atom, addition to the C=C bond. The radiation chemical yields of small molecular products are now reported and correlated with the ESR spectra and yields of molecular products from the saturated analogues, isobutyric acid and barium isobutyrate, in order to provide a detailed mechanism for the radiolysis. The ESR spectrum of barium isobutyrate at -196°C was similar to that of isobutyric acid and is attributed to (i) isobutyrate radical CH 3-Ċ(CH 3)COO -; (ii) isobutyrate anion radical [CH 3-CH(CH 3)COO -] -; and (iii) isopropyl radical CH 3-Ċ(CH 3)H. Conversion of radicals (ii) and (iii) into (i) occurred on warming and second-order decay of (i) was measured at higher temperatures. For isobutyric acid irradiated at 0°C, G(CO 2)=5.4, which is compatible with values for n-carboxylic acids, but in marked disagreement with G(CO 2)=14.4 for isobutyric acid reported by Johnsen. (11) Water was proven to be a significant radiolysis product. CO 2 was the major product from methacrylic acid and barium methacrylate, but in lower yields than from the isobutyrates; the other products were propyne, hydrogen, water, propylene, carbon monoxide and methane, all in relatively low yield.

Structures of dimers formed from poly(barium methacrylate)

Structures of dimers formed from poly(barium methacrylate)

Structural Aspects of Polymerization in Crystalline Ionic Monomers: Comparison of Barium Methacrylate Monohydrate and Anhydrate

Barium methacrylate monohydrate, Ba2 +[CH2=C(CH3)COO] 2H2O, maybe readily polymerized in the crystalline state by γ-irradiation. However, except under special conditions, there is negligible polymer produced when anhydrous barium methacrylate is exposed to γ-irradiation. The differences in polymeriz-ability are considered in relation to the detailed spatial arrangements of the methacrylate molecules and molecular mobility associated with development of disorder.

Crystal structure of anhydrous barium methacrylate

The crystal structure of anhydrous barium methacrylate, Ba[O2, C·C(:CH2)CH3]2 has been determined by the heavy-atom method from X-ray diffractometer data and refined by full-matrix least squares to R 0.042 for 1 578 reflections. Crystals are monoclinic, space group P21/c, a= 12.162(1), b= 8.017(1), c= 10.373(1)A, β= 102.87(1)°, Z= 4. The structure is comprised of sheets of almost coplanar barium ions bridged as an infinite two-dimensional polymer normal to a* by the carboxylate groups. Ba–O distances range from 2.766 to 3.030(5)A about the irregularly eight-co-ordinate cation; in the ligands, the central C–C bond is long [1.498(10), 1.511 (9)A] and one of the ligands is grossly twisted about the bond.

Radiation-Induced Solid-State Polymerization of Derivatives of Methacrylic Acid. VII. A Differential Scanning Calorimetric Investigation of the Dehydration and Polymerization of Barium Methacrylate

Abstract Barium methacrylate monohydrate showed two dehydration steps (at 80 and 110°C), in small crystals, but only one step (at 80° C) in fine powder. The equilibrium water vapor pres-sure was independent of the degree of hydration and its temperature dependence was found to be log10 pH2O (Torr)=10.70 - 2858/T, giving ΔH (dehyd)=54 ±4 kJ mole−1. Small doses of γ-irradiation at 78° C suppressed the second de-hydration endotherm and shifted the first to higher temperatures. Larger radiation doses caused the endotherm to diminish and be re-placed by a polymerization exotherm. The variations in position with scan rate gave Ea=163 kJ mole−1, similar to the value from isothermal polymerization rate measurements. There was no evidence of polymerization in the anhydrate except at the decompo-sition temperature.

Radiation-Induced Solid-State Polymerization of Derivatives of Methacrylic Acid. VII. Postirradiation Polymerization of Barium Methacrylate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRadiation-Induced Solid-State Polymerization of Derivatives of Methacrylic Acid. VII. Postirradiation Polymerization of Barium MethacrylateM. J. Bowden, J. H. O'Donnell, and R. D. SothmanCite this: Macromolecules 1972, 5, 3, 269–274Publication Date (Print):May 1, 1972Publication History Published online1 May 2002Published inissue 1 May 1972https://doi.org/10.1021/ma60027a008RIGHTS & PERMISSIONSArticle Views42Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (652 KB) Get e-Alerts Get e-Alerts

The Solid-State Polymerization of Hydrated Barium Methacrylate

The Solid-State Polymerization of Hydrated Barium Methacrylate

Radiation-Induced Solid-state Polymerization in Some Methacrylates

Abstract This paper presents a comparison of some of our results on the polymerization of methacrylic acid, octadecyl methacrylate, zinc methacrylate, and barium methacrylate monohydrate in the solid state. Polymerization was initiated by cobalt-60 γ rays, both in-source and post-irradiation polymerization techniques being used. Electron spin resonance studies showed that the polymerization proceeded by a free radical mechanism in all cases. The initial radicals formed by irradiation at low temperatures added a first monomer unit about 100° below the temperature of long-chain polymerization. Some radical decay occurred in the early stages of polymerization. The rate of polymerization increased rapidly, approaching the melting point or other phase change in the monomer.

Dehydration and polymerization of barium methacrylate monohydrate

Dehydration and polymerization of barium methacrylate monohydrate

Dehydration of barium methacrylate in air

Dehydration of barium methacrylate in air

ESR spectra of poly(methacrylic acid) and poly(methyl methacrylate): Reinterpretation of the 9‐line spectrum

AbstractThe temperature dependence of the ESR spectra of poly(methacrylic acid) and poly‐(methyl methacrylate) γ‐irradiated at room temperature was studied between −196°C and +25°C. The conventional 9‐line spectrum was observed throughout this range with no significant spectral change, in contrast to the propagating radical ··· CH2°C(CH3)COOR found in methacrylic acid monomer or barium methacrylate dihydrate irradiated at −196°C. In addition, the irradiation of methacrylic acid monomer with a low dose at 0°C gave the same 13‐line spectrum as that of the propagating radical obtained by the irradiation at −196°C, while prolonged irradiation at 0°C gave the same conventional 9‐line spectrum as that of poly(methacrylic acid) or poly(methyl methacrylate). The conventional 9‐line spectrum has a much weaker 4‐line component than that of the propagating radical. The difference comes from the surrounding matrix, and the conventional 9‐line spectrum is well interpreted by introducing the concept of the distribution of the conformational angle in the irregular polymer matrix. From simulation of the ESR spectrum, it was found that the intensity of the 4‐line component is very sensitive to the distribution, and that the observed 9‐line spectrum is well reproduced assuming a Gaussian distribution (half‐height width of 5–6°) around the most probable conformation which is nearly the same as that of the propagating radical, where the conformational angles of the two CHβ bonds to the half‐filled p‐orbital are 55° and 65°.

Radiation induced solid state polymerization of derivatives of methacrylic acid. VI. Polymerization of barium methacrylate dihydrate during irradiation

AbstractCrystalline barium methacrylate dihydrate polymerized during gamma irradiation at 15–35°C. Sigmoidal shaped conversion curves were obtained. The induction period decreased markedly with increase in temperature or dose rate. The polymerization rate(approximately constant from 25–75% conversion) increased with dose rate, corresponding to an exponent of about 0.5, but was almost independent of temperature. ESR spectra showed that the radical concentration increased linearly with time from the commencement of irradiation giving G(radicals) = 7.6 ± 0.5 at 25°C and the same value at 15°C. The radical concentration decreased during the polymerization period, but then increased again. The induction period was attributed to physical trapping of short‐chain propagating radicals.

Radiation Induced Solid State Polymerization of Derivatives of Methacrylic Acid. V. An Electron Spin Resonance Study of Radical-Molecule and Radical-Radical Reactions in Barium Methacrylate Dihydrate

Radiation Induced Solid State Polymerization of Derivatives of Methacrylic Acid. V. An Electron Spin Resonance Study of Radical-Molecule and Radical-Radical Reactions in Barium Methacrylate Dihydrate

Solid state polymerization of zinc methacrylate

AbstractZinc methacrylate has been polymerized in the solid state by the post‐irradiation technique at 89.5°C. The polymer produced was less isotactic than that obtained from barium methacrylate dihydrate when polymerized under similar conditions. The tacticity of the poly(zinc methacrylate) differed markedly from the polymer produced in the liquid phase from methyl methacrylate or methacrylic acid. X‐ray studies of the zinc methacrylate showed the monomer to have an orthorhombic unit cell with lattice constants of a = 17.94Å, b = 9.16 Å, and c = 13.2 Å. There are 8 molecules per unit cell and the symmetry can be classified as either Pnam or Pna2. The anhydrous monomer shows pronounced thermal polymerization at 89.5°C and the radiation‐induced reaction shows no measurable intensity dependency over a 6 fold change in dose rate.

Radiation-induced solid-state polymerization of derivatives of methacrylic acid. IV. Electron spin resonance spectra of barium methacrylate dihydrate

The esr spectrum of γ-irradiated barium methacrylate dihydrate at -196°, attributed to the radical (CH)ĊCOO, was observed to change to the spectrum characteristic of the propagating radical RCHĊ(CH)COO on warming above -100°. This transformation was temperature and time dependent. The spectrum of the propagating radical after several days at -80° consisted of 9 lines with hfs of 11.5 G and an increasing intensity distribution. Immediately on warming to 50° the spectrum was similar, but on cooling back to -80° an alternating intensity distribution was observed, and further cooling to -154° resulted in splitting of the intermediate lines; this effect was reversible. When maintained at 50°, the intensities of the intermediate lines decreased continuously so that the increasing intensity distribution changed to an alternating intensity distribution and finally to a 5-line spectrum. These different spectra are all attributed to the methacrylate propagating radical and are considered to result from different conformations of the β-methylene carbon-hydrogen bonds. The conformation of the radical, and hence the esr spectrum, is believed to depend on (1) the length of the radical chain, (2) the temperature, and (3) the environment. Various models are considered to explain the changes in conformation.