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Sample records for resin tulsion ch-96

  1. Radiotracer application for characterization of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC

    Energy Technology Data Exchange (ETDEWEB)

    Singare, P.U. [Bhavan' s College, Mumbai (India). Dept. of Chemistry

    2015-12-15

    Radio isotopic tracer technique as one of the versatile nondestructive technique is employed to evaluate the performance of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC. The evaluation was made on the basis of ion-isotopic exchange reaction kinetics by using {sup 131}I and {sup 82}Br radioactive tracer isotopes. It was observed that for both the resins, the values of specific reaction rate (min{sup -1}), amount of ion exchanged (mmol) and initial rate of ion exchange (mmol/min) were calculated to be lower for bromide ion-isotopic exchange reaction than that for iodide ion-isotopic exchange reaction. It was observed that for iodide ion-isotopic exchange reaction under identical experimental conditions of 30.0 C, 1.000 g of ion exchange resins and 0.001 mol/L labeled iodide ion solution, the values of specific reaction rate (min{sup -1}), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log K{sub d} were calculated as 0.377, 0.212, 0.080 and 15.5 respectively for Dowex SBR LC resin, which was higher than 0.215, 0.144, 0.031 and 14.1 respectively as that obtained for Tulsion A23 resins. Also at a constant temperature of 30.0 C, as the concentration of labeled iodide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of iodide ions exchanged increases from 84.75 % to 90.20 % for Dowex SBR LC resins which was higher than increases from 57.66 % to 62.38 % obtained for Tulsion A23 resins. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate superior performance of Dowex SBR LC over Tulsion A23 resins under identical experimental conditions.

  2. Plastic casting resin poisoning

    Science.gov (United States)

    Epoxy poisoning; Resin poisoning ... Epoxy and resin can be poisonous if they are swallowed or their fumes are breathed in. ... Plastic casting resins are found in various plastic casting resin products.

  3. Resin composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Peutzfeldt, Anne; Lussi, Adrian

    2014-01-01

    OBJECTIVE: To investigate how the modulus of elasticity of resin composites influences marginal quality in restorations submitted to thermocyclic and mechanical loading. METHODS: Charisma, Filtek Supreme XTE and Grandio were selected as they were found to possess different moduli of elasticity...... of resin composite (p=0.81) on the quality of dentine margins was observed, before or after loading. Deterioration of all margins was evident after loading (p....008). CONCLUSIONS: The resin composite with the highest modulus of elasticity resulted in the highest number of gap-free enamel margins but with an increased incidence of paramarginal enamel fractures. CLINICAL SIGNIFICANCE: The results from this study suggest that the marginal quality of restorations can...

  4. Resin-Powder Dispenser

    Science.gov (United States)

    Standfield, Clarence E.

    1994-01-01

    Resin-powder dispenser used at NASA's Langley Research Center for processing of composite-material prepregs. Dispenser evenly distributes powder (resin polymer and other matrix materials in powder form) onto wet uncured prepregs. Provides versatility in distribution of solid resin in prepreg operation. Used wherever there is requirement for even, continuous distribution of small amount of powder.

  5. Acetylene terminated matrix resins

    Science.gov (United States)

    Goldfarb, I. J.; Lee, Y. C.; Arnold, F. E.; Helminiak, T. E.

    1985-01-01

    The synthesis of resins with terminal acetylene groups has provided a promising technology to yield high performance structural materials. Because these resins cure through an addition reaction, no volatile by-products are produced during the processing. The cured products have high thermal stability and good properties retention after exposure to humidity. Resins with a wide variety of different chemical structures between the terminal acetylene groups are synthesized and their mechanical properties studied. The ability of the acetylene cured polymers to give good mechanical properties is demonstrated by the resins with quinoxaline structures. Processibility of these resins can be manipulated by varying the chain length between the acetylene groups or by blending in different amounts of reactive deluents. Processing conditions similar to the state-of-the-art epoxy can be attained by using backbone structures like ether-sulfone or bis-phenol-A. The wide range of mechanical properties and processing conditions attainable by this class of resins should allow them to be used in a wide variety of applications.

  6. Method for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W [Harrisonville, MO; Hand, Thomas E [Lee's Summit, MO; DeLaurentiis, Gary M [Jamestown, CA

    2008-12-09

    A resin recycling method that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The method includes receiving the resin in container form. The containers are then ground into resin particles. The particles are exposed to a solvent, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. After separating the particles and the resin, a solvent removing agent is used to remove any residual solvent remaining on the resin particles after separation.

  7. Canadian synthetic resins industry

    Energy Technology Data Exchange (ETDEWEB)

    Margeson, J. [Industry Canada, Ottawa, ON (Canada)

    2000-06-01

    The growth of the synthetic resin industry in Canada is described. In 1999 the industry had shipments totalling $6.3 billion and employed about 9,000 people in 105 establishments. The industry is concentrated in Alberta, Ontario and Quebec. Plants in Alberta produce commodity-grade thermoplastic resins from raw materials derived mainly from natural gas, whereas plants in Ontario and Quebec produce both thermoplastic and thermoset resins using raw materials derived from both crude oil and natural gas. Sixty-four per cent of the synthetic reins produced in Canada, worth about $4.1 billion, are exported. This is offset by imports of 68 per cent of domestic consumption, (valued at $5.0 billion) reflecting rationalization and specialization of the resin industry on a continental basis. Process and product technologies used in Canada are up-to-date and licensed from parent or other foreign chemical companies. Capital investment in the Canadian resin industry is lagging behind investment in the United States, however, this is expected to change once the impact of recent investments in the industry in Alberta is reflected in the statistics. A five to seven per cent real average annual growth in world-wide consumption is predicted over the next five years. Growth in North America is projected to be in the three to four per cent range. The Alberta-based component of the industry, being relatively new, is expected to improve its ability to compete globally in commodity thermoplastics. In contrast, the plants in Ontario and Quebec suffer from the fact that they were built prior to the Free Trade Agreement and were designed to satisfy domestic requirements. They are attempting to compensate for their lack of economics of scale by developing strategies to supply niche products. 8 figs.

  8. Flame Retardant Epoxy Resins

    Science.gov (United States)

    Thompson, C. M.; Smith, J. G., Jr.; Connell, J. W.; Hergenrother, P. M.; Lyon, R. E.

    2004-01-01

    As part of a program to develop fire resistant exterior composite structures for future subsonic commercial aircraft, flame retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured epoxies were characterized by thermogravimetric analysis, propane torch test, elemental analysis and microscale combustion calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness of plaques of several cured formulations was determined on single-edge notched bend specimens. The chemistry and properties of these new epoxy formulations are discussed.

  9. System for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2010-11-23

    A resin recycling system that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The system includes receiving the resin in container form. A grinder grinds the containers into resin particles. The particles are exposed to a solvent in one or more solvent wash vessels, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. A separator is used to separate the resin particles and the solvent. The resin particles are then placed in solvent removing element where they are exposed to a solvent removing agent which removes any residual solvent remaining on the resin particles after separation.

  10. Paramagnetic epoxy resin

    Directory of Open Access Journals (Sweden)

    E. C. Vazquez Barreiro

    2017-01-01

    Full Text Available This work illustrates that macrocycles can be used as crosslinking agents for curing epoxy resins, provided that they have appropriate organic functionalities. As macrocycles can complex metal ions in their structure, this curing reaction allows for the introduction of that metal ion into the resin network. As a result, some characteristic physical properties of the metallomacrocycle could be transferred to the new material. The bisphenol A diglycidyl ether (BADGE, n = 0 and hemin (a protoporphyrin IX containing the Fe(III ion, and an additional chloride ligand have been chosen. The new material has been characterized by differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, Fourier Transform Infrared (FT-IR, Nuclear Magnetic Resonance (NMR, Transmission Electron Microscopy (TEM, and magnetic susceptibility measurements. Fe(III remains in the high-spin state during the curing process and, consequently, the final material exhibits the magnetic characteristics of hemin. The loss of the chlorine atom ligand during the cure of the resin allows that Fe(III can act as Lewis acid, catalyzing the crosslinking reactions. At high BADGE n = 0/hemin ratios, the formation of ether and ester bonds occurs simultaneously during the process.

  11. Cure shrinkage in casting resins

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, J. Brock [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    A method is described whereby the shrinkage of a casting resin can be determined. Values for the shrinkage of several resin systems in frequent use by Sandia have been measured. A discussion of possible methods for determining the stresses generated by cure shrinkage and thermal contraction is also included.

  12. [Acrylic resin removable partial dentures

    NARCIS (Netherlands)

    Baat, C. de; Witter, D.J.; Creugers, N.H.J.

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of

  13. Contact allergy to epoxy resin

    DEFF Research Database (Denmark)

    Bangsgaard, Nannie; Thyssen, Jacob Pontoppidan; Menné, Torkil

    2012-01-01

    Background. Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown....... Objectives. To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work-related consequences. Patients/methods. The dataset comprised 20 808 consecutive dermatitis...... patients patch tested during 2005-2009. All patients with an epoxy resin-positive patch test were sent a questionnaire. Results. A positive patch test reaction to epoxy resin was found in 275 patients (1.3%), with a higher proportion in men (1.9%) than in women (1.0%). The prevalence of sensitization...

  14. [Acrylic resin removable partial dentures].

    Science.gov (United States)

    de Baat, C; Witter, D J; Creugers, N H J

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of removable partial dentures, the acrylic resin removable partial denture has 3 favourable aspects: the economic aspect, its aesthetic quality and the ease with which it can be extended and adjusted. Disadvantages are an increased risk of caries developing, gingivitis, periodontal disease, denture stomatitis, alveolar bone reduction, tooth migration, triggering of the gag reflex and damage to the acrylic resin base. Present-day indications are ofa temporary or palliative nature or are motivated by economic factors. Special varieties of the acrylic resin removable partial denture are the spoon denture, the flexible denture fabricated of non-rigid acrylic resin, and the two-piece sectional denture. Furthermore, acrylic resin removable partial dentures can be supplied with clasps or reinforced by fibers or metal wires.

  15. Chromatography resin support

    Science.gov (United States)

    Dobos, James G.

    2002-01-01

    An apparatus and method of using an improved chromatography resin support is disclosed. The chromatography support platform is provided by a stainless steel hollow cylinder adapted for being inserted into a chromatography column. An exterior wall of the stainless steel cylinder defines a groove for carrying therein an "O"-ring. The upper surface of the stainless steel column is covered by a fine stainless steel mesh welded to the edges of the stainless steel cylinder. When placed upon a receiving ledge defined within a chromatography column, the "O"-ring provides a fluid tight seal with the inner edge wall of the chromatography cylinder. The stainless steel mesh supports the chromatography matrix and provides a back flushable support which is economical and simple to construct.

  16. 21 CFR 178.3930 - Terpene resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Terpene resins. 178.3930 Section 178.3930 Food and... and Production Aids § 178.3930 Terpene resins. The terpene resins identified in paragraph (a) of this... the terpene resins identified in paragraph (b) of this section may be safely used as components of...

  17. Bending characteristics of resin concretes

    Directory of Open Access Journals (Sweden)

    Ribeiro Maria Cristina Santos

    2003-01-01

    Full Text Available In this research work the influence of composition and curing conditions in bending strength of polyester and epoxy concrete is analyzed. Various mixtures of resin and aggregates were considered in view of an optimal combination. The Taguchi methodology was applied in order to reduce the number of tests, and in order to evaluate the influence of various parameters in concrete properties. This methodology is very useful for the planning of experiments. Test results, analyzed by this methodology, shown that the most significant factors affecting bending strength properties of resin concretes are the type of resin, resin content and charge content. An optimal formulation leading to a maximum bending strength was achieved in terms of material parameters.

  18. Bulk-Fill Resin Composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel

    2015-01-01

    the restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization...... for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and three low......-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low-viscosity bulk...

  19. Epoxy hydantoins as matrix resins

    Science.gov (United States)

    Weiss, J.

    1983-01-01

    Tensile strength and fracture toughness of castings of the hydantoin resins cured with methylenedianiline are significantly higher than MY 720 control castings. Water absorption of an ethyl, amyl hydantoin formulation is 2.1 percent at equilibrium and Tg's are about 160 C, approximately 15 deg below the final cure temperature. Two series of urethane and ester-extended hydantoin epoxy resins were synthesized to determine the effect of crosslink density and functional groups on properties. Castings cured with methylenedianiline or with hexahydrophthalic anhydride were made from these compounds and evaluated. The glass transition temperatures, tensile strengths and moduli, and fracture toughness values were all much lower than that of the simple hydantoin epoxy resins. Using a methylene bishydantoin epoxy with a more rigid structure gave brittle, low-energy fractures, while a more flexible, ethoxy-extended hydantoin epoxy resin gave a very low Tg.

  20. Liquid monobenzoxazine based resin system

    Science.gov (United States)

    Tietze, Roger; Nguyen, Yen-Loan; Bryant, Mark

    2014-10-07

    The present invention provides a liquid resin system including a liquid monobenzoxazine monomer and a non-glycidyl epoxy compound, wherein the weight ratio of the monobenzoxazine monomer to the non-glycidyl epoxy compound is in a range of about 25:75 to about 60:40. The liquid resin system exhibits a low viscosity and exceptional stability over an extended period of time making its use in a variety of composite manufacturing methods highly advantageous.

  1. Karakteristik Komposit Resin Berkemampuan Mengalir

    Directory of Open Access Journals (Sweden)

    Bambang Irawan

    2015-10-01

    Full Text Available The use of resin composites as posterior restoratives has markedly increased over the past decade. The patients demand for better esthetics, concerns related to possible mercury toxicity from amalgam and improvements in resin composite materials have significantly contributed the popularity of these materials. Early problems related to composites included excessive wear, less of anatomic form, post operative sensitivity, secondary caries and marginal leakage. Marginal adaptation still remains an unavoidable problem for composite restoration, especially at the gingival wall of cervical or Class II restoration. In an attempt to improve marginal sealing, many techniques and lining materials have been designed. To reduce stress generated by polymerization shrinkage, applying and curing of resin composites in layers is often recommended. Using a thick adhesive layer or low-viscosity resin may, due to its elastic properties, serve as a flexible intermediate layer and compensate for the polymerization stress created in resin composite. Flowable composites were created by retaining the same small particle size of traditional hybrid composite but reducing the filler content and allowing the increased resin to reduce the viscosity of the mixture. Flowable composites were introduced in 1996 as liners, fissure sealants and also in tunnel preparations. They have been suggested for Class I, II, III and V cavity restorations, preventive resin restorations and composite, porcelain and amalgam repairing. Their usage as a liner under high filled resins in posterior restorations has been shown to improve the adaptation of composites and effectively achieve clinically acceptable results. This article attempts to give a broad characteristics of different types of flowable composites. 

  2. Low Melt Viscosity Resins for Resin Transfer Molding

    Science.gov (United States)

    Harris, Frank W.

    2002-01-01

    In recent years, resin transfer molding (RTM) has become one of the methods of choice for high performance composites. Its cost effectiveness and ease of fabrication are major advantages of RTM. RTM process usually requires resins with very low melt viscosity (less than 10 Poise). The optimum RTM resins also need to display high thennal-oxidative stability, high glass transition temperature (T(sub g)), and good toughness. The traditional PMR-type polyimides (e.g. PMR-15) do not fit this requirement, because the viscosities are too high and the nadic endcap cures too fast. High T(sub g), low-melt viscosity resins are highly desirable for aerospace applications and NASA s Reusable Launch Vehicle (RLV) program. The objective of this work is to prepare low-melt viscosity polyimide resins for RTM or resin film infusion (RFI) processes. The approach involves the synthesis of phenylethynyl-terminated imide oligomers. These materials have been designed to minimize their melt viscosity so that they can be readily processed. During the cure, the oligomers undergo both chain extension and crosslinking via the thermal polymerization of the phenylethynyl groups. The Phenylethynyl endcap is preferred over the nadic group due to its high curing temperature, which provides broader processing windows. This work involved the synthesis and polymerization of oligomers containing zig-zag backbones and twisted biphenyl structures. Some A-B type precursors which possessed both nitro and anhydride functionality, or both nitro and amine functionality, were also synthesized in order to obtain the well defined oligomers. The resulting zig-zag structured oligomers were then end-capped with 4-phenylethynylphthalic anhydride (PEPA) for further cure. The properties of these novel imide oligomers are evaluated.

  3. Epoxy Resins in Electron Microscopy

    Science.gov (United States)

    Finck, Henry

    1960-01-01

    A method of embedding biological specimens in araldite 502 (Ciba) has been developed for materials available in the United States. Araldite-embedded tissues are suitable for electron microscopy, but the cutting qualities of the resin necessitates more than routine attention during microtomy. The rather high viscosity of araldite 502 also seems to be an unnecessary handicap. The less viscous epoxy epon 812 (Shell) produces specimens with improved cutting qualities, and has several features—low shrinkage and absence of specimen damage during cure, minimal compression of sections, relative absence of electron beam-induced section damage, etc.—which recommends it as a routine embedding material. The hardness of the cured resin can be easily adjusted by several methods to suit the materials embedded in it. Several problems and advantages of working with sections of epoxy resins are also discussed. PMID:13822825

  4. Process for Molding Nonreinforced (Neat) Resins

    Science.gov (United States)

    Dickerson, G. E.

    1983-01-01

    Void free moldings obtained for neat, condensation, thermosetting resins. Thermally and mechanically treat resin prior to molding to reduce amount of volatiles. With volatiles reduced molding temperature and pressure are applied in way to drive out remaining volatiles during molding.

  5. 21 CFR 177.1680 - Polyurethane resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyurethane resins. 177.1680 Section 177.1680 Food... of Single and Repeated Use Food Contact Surfaces § 177.1680 Polyurethane resins. The polyurethane...) For the purpose of this section, polyurethane resins are those produced when one or more of the...

  6. Method for removing contaminants from plastic resin

    Science.gov (United States)

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2008-12-30

    A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

  7. Method of removing contaminants from plastic resins

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee' s Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

    2008-11-18

    A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

  8. Method of removing contaminants from plastic resins

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert,George W. (Harrisonville, MO); Hand,Thomas E. (Lee' s Summit, MO); Delaurentiis,Gary M. (Jamestown, CA)

    2007-08-07

    A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

  9. 21 CFR 177.1595 - Polyetherimide resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyetherimide resin. 177.1595 Section 177.1595... Components of Single and Repeated Use Food Contact Surfaces § 177.1595 Polyetherimide resin. The polyetherimide resin identified in this section may be safely used as an article or component of an article...

  10. Longevity of resin composite restorations

    Directory of Open Access Journals (Sweden)

    Shisei Kubo

    2011-02-01

    Full Text Available In daily practice, an evidence-based approach is becoming more expected of dentist. However, only outcomes obtained from clinical studies are accepted as evidence. Although many clinical trials have been performed, most of them are short-term studies, whereas long-term studies are likely to provide more reliable evidence. In this article, prospective studies and retrospective longitudinal clinical studies on resin composite restorations were systematically searched with PubMed for literature in English and with Japana Centra Revuo Medicina (Ichushi Web for articles in Japanese. Finally, 21 long-term (8 years or more prospective studies and nine retrospective studies with survival analysis were selected and reviewed from more than 561 papers. The overall findings suggest that at least 60% of resin composite restorations will last more than 10 years when proper materials are applied correctly. Patient-, operator-, material- and tooth-related factors may have an influence on the survival of resin composite restorations. Appropriate maintenance policies based on MI concepts are claimed to enhance the longevity of resin composite restorations.

  11. and phenol–formaldehyde resin

    Indian Academy of Sciences (India)

    Thermosetting resin; magnetic properties; microstructures; heat treatment. 1. Introduction. The ideal insulating soft magnetic composite (SMC) is formed by ferromagnetic .... turns was wound for AC complex permeability measure- ment. Complex permeability spectra were measured by an impedance analyzer (HP 4194A) ...

  12. Occupational exposure to epoxy resins

    NARCIS (Netherlands)

    Terwoert, J.; Kersting, K.

    2014-01-01

    Products based on epoxy resins as a binder have become popular in various settings, among which the construction industry and in windmill blade production, as a result of their excellent technical properties. However, due to the same properties epoxy products are a notorious cause of allergic skin

  13. Resin Diterpenes from Austrocedrus chilensis

    Directory of Open Access Journals (Sweden)

    Verónica Rachel Olate

    2011-12-01

    Full Text Available Seventeen diterpenes belonging to the labdane, abietane and isopimarane skeleton classes were isolated from the resin of the Chilean gymnosperm Austrocedrus chilensis and identified by spectroscopic and spectrometric methods. The diterpene 12-oxo-labda-8(17,13E-dien-19 oic acid is reported for the first time as a natural product and 14 diterpenes are reported for the first time for the species.

  14. Wear rates of resin composites.

    Science.gov (United States)

    Barkmeier, W W; Erickson, R I; Latta, M A; Wilwerding, T M

    2013-01-01

    SUMMARY A laboratory study was conducted to examine the wear of resin composite materials using a generalized wear simulation model. Ten specimens each of five resin composites (Esthet•X [EX], Filtek Supreme Plus [SP], Filtek Z250 [Z2], Tetric EvoCeram [EC], and Z100 Restorative [Z1]) were subjected to wear challenges of 100,000, 400,000, 800,000, and 1,200,000 cycles. The materials were placed in cylinder-shaped stainless-steel fixtures, and wear was generated using a flat stainless-steel antagonist in a slurry of polymethylmethacrylate beads. Wear (mean facet depth [μm] and volume loss [mm(3)]) was determined using a noncontact profilometer (Proscan 2000) with Proscan and ProForm software. Statistical analysis of the laboratory data using analysis of variance and Tukey's post hoc test showed a significant difference (p<0.05) for mean wear facet depth and volume loss for both the number of cycles and resin composite material. Linear regression analysis was used to develop predictive wear rates and volume loss rates. Linear wear was demonstrated with correlation coefficients (R(2)) ranging from 0.914 to 0.995. Mean wear values (mean facet depth [μm]) and standard deviations (SD) for 1200K cycles were as follows: Z1 13.9 (2.0), Z2 26.7 (2.7), SP 30.1 (4.1), EC 31.8 (2.3), and EX 67.5 (8.2). Volume loss (mm(3)) and SDs for 1200K cycles were as follows: Z1 0.248 (0.036), Z2 0.477 (0.044), SP 0.541 (0.072), EC 0.584 (0.037), and EX 1.162 (0.139). The wear rate (μm) and volume loss rate (mm(3)) per 100,000 cycles for the five resin composites were as follows: wear rate Z1 0.58, EC 1.27, Z2 1.49, SP 1.62, and EX 4.35, and volume loss rate Z1 0.009, EC 0.024, Z2 0.028, SP 0.029, and EX 0.075. The generalized wear model appears to be an excellent method for measuring relative wear of resin composite materials.

  15. TASTE MASKING AND FORMULATION OF ONDANSETRON HYDROCHLORIDE MOUTH DISSOLVING TABLETS

    OpenAIRE

    Shyam Raj Subedi, Bhupendra Kumar Poudel; Uttam Budhathoki, Panna Thapa

    2015-01-01

    This study was done to mask the bitter taste of ondansetron HCl using complexing agent, a polacrilex resin: Tulsion 335 and subsequently forming mouth dissolving tablet using superdisintegrants: Croscarmellose sodium and sodium starch glycollate. A preliminary screening was done. Batch process, a most preferential method for drug loading with ion exchange resins was selected. The process was optimized for drug: resin ratio to get maximum drug loading. A ratio of drug: resin at 1:3 was select...

  16. Color stability of different composite resin materials.

    Science.gov (United States)

    Falkensammer, Frank; Arnetzl, Gerwin Vincent; Wildburger, Angelika; Freudenthaler, Josef

    2013-06-01

    Data are needed to better predict the color stability of current composite resin materials. The purpose of this study was to evaluate the impact of different storage solutions on the color stability of different composite resin materials. Different restorative and adhesive composite resin specimens (dual-polymerizing self-adhesive resin cement, autopolymerizing resin-based composite resin, dual-polymerizing resin-based composite resin, nanohybrid composite resin, and microhybrid composite resin) were fabricated and stored in red wine, black tea, chlorhexidine, sodium fluoride, tea tree oil, or distilled water for 4 weeks at 37°C. Color parameters were measured with a colorimeter before and after storage. Total color differences and specific coordinate differences were expressed as ΔE, ΔL, Δa, and Δb. A 2-way and 1-way analysis of variance (ANOVA) with Bonferroni adjustment for multiple comparisons were applied for statistical calculations (α=.05). Red wine caused the most severe discoloration (ΔE >10), followed by black tea with perceptible (ΔE >2.6) to clinically unacceptable discoloration (ΔE >5.5). Colored mouth rinses discolored the materials to a lesser extent with clinically acceptable values. Dual-polymerizing resin adhesives showed a higher amount of discoloration. Current restorative and adhesive composite resin materials discolor over time under the influence of different storage solutions. The composition related to the polymerizing mode seemed to be a causative factor. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  17. Comparison of Cashew Nut Shell Liquid (CNS) Resin with Polyester Resin in Composite Development

    OpenAIRE

    C. C. Ugoamadi

    2013-01-01

    Natural resins can compete effectively with the synthetic ones in composite development. In this research, cashew nuts were picked and processed for the extraction of the resin content. The resin (natural resin) so obtained was mixed with cobalt amine (accelerator), methyl ethyl ketone peroxide (catalyst) to develop two sets of composite specimens – specimens without fibres and specimens reinforced with glass fibres. This method of sample specimen development was repeated with polyester (synt...

  18. 21 CFR 175.380 - Xylene-formaldehyde resins condensed with 4,4′-isopropylidenediphenol-epichlorohydrin epoxy resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Xylene-formaldehyde resins condensed with 4,4â²... Xylene-formaldehyde resins condensed with 4,4′-isopropylidenediphenol-epichlorohydrin epoxy resins. The...) The resins are produced by the condensation of xylene-formaldehyde resin and 4,4...

  19. Advanced resin systems for graphite epoxy composites

    Science.gov (United States)

    Gilwee, W. J.; Jayarajan, A.

    1980-01-01

    The value of resin/carbon fiber composites as lightweight structures for aircraft and other vehicle applications is dependent on many properties: environmental stability, strength, toughness, resistance to burning, smoke produced when burning, raw material costs, and complexity of processing. A number of woven carbon fiber and epoxy resin composites were made. The epoxy resin was commercially available tetraglycidylmethylene dianiline. In addition, composites were made using epoxy resin modified with amine and carboxyl terminated butadiene acrylonitrile copolymer. Strength and toughness in flexure as well as oxygen index flammability and NBS smoke chamber tests of the composites are reported.

  20. Novel silica-based ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

    Eichrom`s highly successful Diphonixo resin resembles a conventional ion exchange resin in its use of sulfonic acid ligands on a styrene- divinylbenzene matrix. Diphonix resin exhibits rapid exchange kinetics that allow economical operation of ion exchange systems. Unlike conventional resins, Diphonix resin contains chelating ligands that are diphosphonic acid groups that recognize and remove the targeted metals and reject the more common elements such as sodium, calcium and magnesium. This latter property makes Diphonix ideal for many industrial scale applications, including those involving waste treatment. For treatment of low-level, transuranic (TRU) and high- level radioactive wastes, Diphonix`s polystyrene backbone hinders its application due to radiolytic stability of the carbon-hydrogen bonds and lack of compatibility with expected vitrification schemes. Polystyrene-based Diphonix is approximately 60% carbon- hydrogen. In response to an identified need within the Department of Energy for a resin with the positive attributes of Diphonix that also exhibits greater radiolytic stability and final waste form compatibility, Eichrom has successfully developed a new, silica-based resin version of Diphonix. Target application for this new resin is for use in environmental restoration and waste management situations involving the processing of low-level, transuranic and high-level radioactive wastes. The resin can also be used for processing liquid mixed waste (waste that contains low level radioactivity and hazardous constituents) including mixed wastes contaminated with organic compounds. Silica-based Diphonix is only 10% carbon-hydrogen, with the bulk of the matrix silica.

  1. Heat-cured Acrylic Resin versus Light-activated Resin: A Patient ...

    African Journals Online (AJOL)

    Context: Although light-activated resins (Eclipse) have been reported to possess superior physical and mechanical properties compared with the heat-cured acrylic resins (Lucitone-199), a few studies have compared overdentures with a locator attachment constructed from heat-cured acrylic resins with those constructed ...

  2. Gold Loading on Ion Exchange Resins in Non-Ammoniacal Resin-Solution Systems

    Directory of Open Access Journals (Sweden)

    Abrar Muslim

    2010-12-01

    Full Text Available The loading of gold using strong base anion exchange resin in non-ammoniac resin-solution (NARS systems has been studied. The loading of gold onto ion exchange resins is affected by polythionate concentration, and trithionate can be used as the baseline in the system. The results also show that resin capacity on gold loading increases due to the increase in the equilibrium thiosulfate concentration in the NARS system. Gold loading performances show the need of optimization the equilibrium concentrations of thiosulfate in the NARS system. Keywords: equilibrium, gold loading, resin capacity, thiosulfate, trithionate

  3. Flexure fatigue of 10 commonly used denture base resins.

    Science.gov (United States)

    Johnston, E P; Nicholls, J I; Smith, D E

    1981-11-01

    The flexure fatigue properties of 10 denture base resins (four different types) were tested. Each specimen underwent two-way testing in a water bath maintained at 37 degrees +/- 1 degree C. A load of 3,650 gm was applied a 342 flexures per minute until the specimen broke. The resin types listed in order of increasing resistance to flexure fatigue are polymethylmethacrylate (PMM) pour resins, PMM thermosetting resins, vinyl resins, and a PMM grafted resin. Although small samples size and scatter of results limit broad application of this data, it is of some significance that the grafted resin Lucitone 199 tended to withstand repeated flexure when compared to the other resins.

  4. Properties of the Carboxylate ion exchange resins; Karboxylatjonbytarmassans egenskaper

    Energy Technology Data Exchange (ETDEWEB)

    Allard, Bert; Dario, Maarten [Oerebro Univ. (Sweden); Boren, Hans [Linkoepings Univ. (Sweden); Torstenfelt, Boerje [Swedpower, Stockholm (Sweden); Puigdomenech, Ignasi; Johansson, Claes [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2002-09-01

    Weakly acidic, carboxylic resin has been selected, together with strong base anion resins, for water purification at the Forsmark 1 and 2 reactors. For the strong (but not the weak) ion exchange resin the Nuclear Power Inspectorate has given permission to dispose the spent resins in the SFR 1 (the Final Repository for Radioactive Operational Waste). This report gives a review of the carboxylic resins and comes to the conclusion that the resins are very stable and that there should not exist any risks for increased leaching of radionuclides from SFR 1 if these resins are disposed (compared to the strong resins)

  5. Comparison of Cashew Nut Shell Liquid (CNS Resin with Polyester Resin in Composite Development

    Directory of Open Access Journals (Sweden)

    C. C. Ugoamadi

    2013-12-01

    Full Text Available Natural resins can compete effectively with the synthetic ones in composite development. In this research, cashew nuts were picked and processed for the extraction of the resin content. The resin (natural resin so obtained was mixed with cobalt amine (accelerator, methyl ethyl ketone peroxide (catalyst to develop two sets of composite specimens – specimens without fibres and specimens reinforced with glass fibres. This method of sample specimen development was repeated with polyester (synthetic resin. Compressive and tensile strength tests conducted proved that composites developed with cashew nut shell liquid (CNSL resin were comparable to those developed with polyester resin. In the results, CNSL has an ultimate compressive strength of 55MPa compared to that of polyester resin with an ultimate strength of 68MPa. The result of tensile strength proved cashew nut shell liquid resin (with ultimate strength of 44MPa to be better than polyester resin with 39MPa as ultimate tensile strength. This means that natural resins could be a better substitute for the synthetic ones when the required quantities of fibers (reinforcements and fillers are used in the fibre-reinforced plastic composite developments.

  6. TMI-2 purification demineralizer resin study

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, J D; Osterhoudt, T R

    1984-05-01

    Study of the Makeup and Purification System demineralizers at TMI-2 has established that fuel quantities in the vessels are low, precluding criticality, that the high radioactive cesium concentration on the demineralizer resins can be chemically removed, and that the demineralizer resins can probably be removed from the vessels by sluicing through existing plant piping. Radiation measurements from outside the demineralizers establishing that there is between 1.5 and 5.1 (probably 3.3) lb of fuel in the A vessel and less than that amount in the B vessel. Dose rates up to 2780 R per hour were measured on contact with the A demineralizer. Remote visual observation of the A demineralizer showed a crystalline crust overlaying amber-colored resins. The cesium activity in solid resin samples ranged from 220 to 16,900 ..mu..Ci/g. Based on this information, researchers concluded that the resins cannot be removed through the normal pathway in their present condition. Studies do show that the resins will withstand chemical processing designed to rinse and elute cesium from the resins. The process developed should work on the TMI-2 resins.

  7. [Delayed asthma bronchiale due to epoxy resin].

    Science.gov (United States)

    Authried, Georg; Al-Asadi, Haifaa; Møller, Ulla; Sherson, David Lee

    2013-10-28

    Epoxy resin is a low molecular weight agent, which can cause both acute and delayed allergic reactions. However, it is known causing skin reactions with direct or airborne contact. Rarely it can cause airway reactions like asthma bronchiale. We describe a case of a windmill worker who developed delayed asthma bronchiale due to airborne contact with epoxy resin.

  8. Facile synthesis of hypercrosslinked resins via chloromethylation ...

    Indian Academy of Sciences (India)

    A sort of non-polystyrene type hypercrosslinked resin was firstly synthesized through chloromethylation of simple aryl molecules (benzene, toluene, naphthalene, diphenyl), succedent continuous Friedel–Crafts alkylation polymerization and post-crosslinking reaction. The chemical and porous structures of these novel resins ...

  9. 21 CFR 177.1655 - Polysulfone resins.

    Science.gov (United States)

    2010-04-01

    ... acetic acid in distilled water, and n-heptane, yield total extractives in each extracting solvent not to... (a) of this section may contain optional adjuvant substances required in the production of such basic resins. The optional adjuvant substances required in the production of the basic polysulfone resins may...

  10. Physical Properties of Synthetic Resin Materials

    Science.gov (United States)

    Fishbein, Meyer

    1939-01-01

    A study was made to determine the physical properties of synthetic resins having paper, canvas, and linen reinforcements, and of laminated wood impregnated with a resin varnish. The results show that commercial resins have moduli of elasticity that are too low for structural considerations. Nevertheless, there do exist plastics that have favorable mechanical properties and, with further development, it should be possible to produce resin products that compare favorably with the light-metal alloys. The results obtained from tests on Compound 1840, resin-impregnated wood, show that this material can stand on its own merit by virtue of a compressive strength four times that of the natural wood. This increase in compressive strength was accomplished with an increase of density to a value slightly below three times the normal value and corrected one of the most serious defects of the natural product.

  11. Disinfection of denture base acrylic resin.

    Science.gov (United States)

    Lin, J J; Cameron, S M; Runyan, D A; Craft, D W

    1999-02-01

    During repair or adjustments of acrylic resin removable complete and partial dentures, particles of the acrylic resin from the interior of the prosthesis may expose dental personnel to microbial health hazards if the prosthesis has not been thoroughly disinfected. This study investigates the efficacy of a commercially prepared microbial disinfectant (Alcide) on the external and internal surfaces of acrylic resins. Four groups of acrylic resin were incubated in an experimental model to simulate the oral environment over time. Specimens were treated in 2 groups, disinfected and not disinfected, and then further grouped by breaking and not breaking. Analysis was performed with microbial colony counts, SEM, and statistical analyses. Viable microorganisms still remain on the internal and external surfaces of treated resins. Chlorine dioxide reduces, but does not eliminate, viable microorganisms on these dental prostheses.

  12. Structure Property Relationships of Biobased Epoxy Resins

    Science.gov (United States)

    Maiorana, Anthony Surraht

    The thesis is about the synthesis, characterization, development, and application of epoxy resins derived from sustainable feedstocks such as lingo-cellulose, plant oils, and other non-food feedstocks. The thesis can be divided into two main topics 1) the synthesis and structure property relationship investigation of new biobased epoxy resin families and 2) mixing epoxy resins with reactive diluents, nanoparticles, toughening agents, and understanding co-curing reactions, filler/matrix interactions, and cured epoxy resin thermomechanical, viscoelastic, and dielectric properties. The thesis seeks to bridge the gap between new epoxy resin development, application for composites and advanced materials, processing and manufacturing, and end of life of thermoset polymers. The structures of uncured epoxy resins are characterized through traditional small molecule techniques such as nuclear magnetic resonance, high resolution mass spectrometry, and infrared spectroscopy. The structure of epoxy resin monomers are further understood through the process of curing the resins and cured resins' properties through rheology, chemorheology, dynamic mechanical analysis, tensile testing, fracture toughness, differential scanning calorimetry, scanning electron microscopy, thermogravimetric analysis, and notched izod impact testing. It was found that diphenolate esters are viable alternatives to bisphenol A and that the structure of the ester side chain can have signifi-cant effects on monomer viscosity. The structure of the cured diphenolate based epoxy resins also influence glass transition temperature and dielectric properties. Incorporation of reactive diluents and flexible resins can lower viscosity, extend gel time, and enable processing of high filler content composites and increase fracture toughness. Incorpora-tion of high elastic modulus nanoparticles such as graphene can provide increases in physical properties such as elastic modulus and fracture toughness. The synthesis

  13. Evaluation of Resin-Resin Interface in Direct Composite Restoration Repair

    Science.gov (United States)

    Stoleriu, S.; Andrian, S.; Pancu, G.; Nica, I.; Iovan, G.

    2017-06-01

    The aim of this study was to evaluate the resin-resin interface when a universal bonding agent was used in two different strategies in direct restoration repair. Two composite resins (a micro-filled hybrid and a nano-filled hybrid) as old restorations that have to be repair, a universal bonding agent and a micro-filled hybrid composite resin (different then that aged) as new material for repair were chosen for the study. Non-aged samples were used as control and aged samples were used as study groups. The universal bonding agent was applied in etch-and-rinse and in self-etch strategies. The interface between old and new composite resins was evaluated by SEM and the microleakage was assessed by scoring the dye penetration. Very good adaptation of the two different composite resins placed in direct contact in non-aged samples was recorded. No gaps or defects were visible and strong resin-resin contact was observed. After aging, enlargement of resin-resin junction were observed in most of the samples and a increased dye penetration was recorded irrespective of the strategy (etch-and-rinse or self-etch) used for bonding agent application.

  14. Effect of resin matrix composition on the translucency of experimental dental composite resins.

    Science.gov (United States)

    Azzopardi, Natasha; Moharamzadeh, Keyvan; Wood, Duncan J; Martin, Nicolas; van Noort, Richard

    2009-12-01

    The purpose of this study was to investigate the effect of the resin matrix composition on the translucency of experimental dental composite resins. Three types of unfilled resin matrices (TEGDMA-, UDMA- and BisGMA-based) were formulated and light cured. In addition, six different experimental dental composite resins with constant filler loading but varying in the type of monomer and the content of BisGMA were fabricated. Discs of each test material with 15.5mm diameter and 1.0mm thickness were prepared (N=3) and light cured. Total and diffuse transmittance values for each sample were measured using a UV/VIS spectrophotometer with the range of readings from 380 to 700nm. Difference in color was measured using the CIE Lab system. Statistical analysis by one-way ANOVA followed by Tukey's test showed that there was no statistically significant difference in transmittance values between the three unfilled resins. However, with the addition of filler, BisGMA-containing composite resins showed significantly higher transmittance values than the UDMA- and TEGDMA-based composite resins. Regression analysis revealed that there was a linear correlation between the percentage of BisGMA in the resin matrix and the total and diffuse translucency. The amount of BisGMA used in the resin matrix has a significant effect on the translucency of silica filler-containing dental composite resins.

  15. Investigation of fossil resins and amber

    Directory of Open Access Journals (Sweden)

    E.Yu. Makarova

    2017-05-01

    Full Text Available Fossil resins and amber are a product of lithogenesis of resinous substances of higher plants – resinite. These components of plants, like other lipoid ingredients (suberins, coutines, sporinins, natural rubbers are resistant to microbial action, so they are well preserved in bacterial processing of organic matter in the stages of sedimento- and diagenesis, and are well diagnosed in microscopic studies. They occur in a rather wide age range of sedimentary rocks. The amber of the Baltic region of the Eocene age is most fully studied. The article presents the results of a study of the collection of fossil resins and amber from various regions of the world. Samples were studied microscopically; carbon isotope analysis, infrared spectroscopy (IR spectroscopy were performed. The most informative analysis of high-molecular polymeric compounds is IR spectroscopy. It was found that in the analyzed samples of fossil resins of different ages, aromatic compounds are not observed, most of which are first volatilized in fossilization processes. The possibility of influencing the group composition of amber and amber-like resins for sedimentation, diagenesis and catagenesis is discussed. The IR spectra of fossil and modern resin conifers are compared. Using the IR spectroscopy method, an attempt was made to identify the botanical origin of fossil resins.

  16. 21 CFR 177.2260 - Filters, resin-bonded.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Filters, resin-bonded. 177.2260 Section 177.2260... Components of Articles Intended for Repeated Use § 177.2260 Filters, resin-bonded. Resin-bonded filters may... of this section. (a) Resin-bonded filters are prepared from natural or synthetic fibers to which have...

  17. Comparison of Cashew Nut Shell Liquid (CNS ) Resin with ...

    African Journals Online (AJOL)

    Natural resins can compete effectively with the synthetic ones in composite development. In this research, cashew nuts were picked and processed for the extraction of the resin content. The resin (natural resin) so obtained was mixed with cobalt amine (accelerator), methyl ethyl ketone peroxide (catalyst) to develop two sets ...

  18. 76 FR 4936 - Granular Polytetrafluoroethylene Resin From Italy

    Science.gov (United States)

    2011-01-27

    ... COMMISSION Granular Polytetrafluoroethylene Resin From Italy AGENCY: United States International Trade... antidumping duty order on granular polytetrafluoroethylene resin (``granular PTFE resin'') from Italy. DATES... on granular PTFE resin from Italy and Japan (75 FR 67082-67083 and 67105-67108, November 1, 2010...

  19. Traumatic resin ducts as indicators of bark beetle outbreaks

    Science.gov (United States)

    R. Justin DeRose; Matthew F. Bekker; James N. Long

    2017-01-01

    The formation of traumatic resin ducts (TRDs) represents an important induced defense in woody plants that enhances oleoresin production and flow in response to environmental perturbations. In some genera (Pinus), resin ducts are copious and conspicuous; however, in others (Picea), resin ducts are relatively rare. The occurrence and strength of resin ducts, in...

  20. Melamine-modified urea formaldehyde resin for bonding particleboards

    Science.gov (United States)

    Chung-Yun Hse; Feng Fu; Hui Pan

    2008-01-01

    For the development of a cost-effective melamine-modified urea formaldehyde resin (MUF), the study evaluated the effects of reaction pH and melamine content on resin properties and bond performance of the MUF resin adhesive systems. Eight resins, each with three replicates, were prepared in a factorial experiment that included two formulation variables: two reaction...

  1. Characterizing Delamination Resistance of Toughened Resin Composites

    Science.gov (United States)

    Obrien, T. K.

    1984-01-01

    The delamination resistance of toughened resin composites was studied. Both the edge delamination test (EDT) and the double-cantilever-beam (DCB) test provided a useful ranking of improvements in delamination resistance between brittle and tough resin composites. Several layups were designed for the edge delamination test to cover a wide range of mixed-mode conditions. The DCB and the various layups of the EDT were then used to characterize the interlaminar fracture behavior of brittle and toughened resin composites subjected to both static and cyclic loading.

  2. Hydraulic Permeability of Resorcinol-Formaldehyde Resin

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul Allen [ORNL

    2010-01-01

    An ion exchange process using spherical resorcinol-formaldehyde (RF) resin is the baseline process for removing cesium from the dissolved salt solution in the high-level waste tanks at the Hanford Site, using large scale columns as part of the Waste Treatment Plant (WTP). The RF resin is also being evaluated for use in the proposed small column ion exchange (SCIX) system, which is an alternative treatment option at Hanford and at the Savannah River Site (SRS). A recirculating test loop with a small ion exchange column was used to measure the effect of oxygen uptake and radiation exposure on the permeability of a packed bed of the RF resin. The lab-scale column was designed to be prototypic of the proposed Hanford columns at the WTP. Although the test equipment was designed to model the Hanford ion exchange columns, the data on changes in the hydraulic permeability of the resin will also be valuable for determining potential pressure drops through the proposed SCIX system. The superficial fluid velocity in the lab-scale test (3.4-5.7 cm/s) was much higher than is planned for the full-scale Hanford columns to generate the maximum pressure drop expected in those columns (9.7 psig). The frictional drag from this high velocity produced forces on the resin in the lab-scale tests that matched the design basis of the full-scale Hanford column. Any changes in the resin caused by the radiation exposure and oxygen uptake were monitored by measuring the pressure drop through the lab-scale column and the physical properties of the resin. Three hydraulic test runs were completed, the first using fresh RF resin at 25 C, the second using irradiated resin at 25 C, and the third using irradiated resin at 45 C. A Hanford AP-101 simulant solution was recirculated through a test column containing 500 mL of Na-form RF resin. Known amounts of oxygen were introduced into the primary recirculation loop by saturating measured volumes of the simulant solution with oxygen and reintroducing

  3. In-depth disinfection of acrylic resins.

    Science.gov (United States)

    Chau, V B; Saunders, T R; Pimsler, M; Elfring, D R

    1995-09-01

    This study demonstrated that bacteria penetrate three kinds of dental acrylic resin after a short time period. Samples of acrylic resin were contaminated with a variety of bacteria and were then placed in three different disinfecting solutions as directed by the manufacturers. After the specific dilution and immersion time, cultures were made from the resin samples. The only effective disinfectant was a 0.525% solution of sodium hypochlorite at a 10-minute immersion. It disinfected not only the surfaces but also the bacteria that penetrated the surfaces to a depth of 3 mm.

  4. Cobalt Ions Improve the Strength of Epoxy Resins

    Science.gov (United States)

    Stoakley, D. M.; St. Clair, A. K.

    1986-01-01

    Technique developed for improving mechanical strength of epoxy resins by adding cobalt ions in form of tris(acetylacetonato)cobalt (III) complex. Solid cast disks prepared from cobalt ion-containing epoxy resins tested for flexural strength and stiffness. Incorporation of cobalt ions into epoxies increased flexural strength of resins by 10 to 95 percent. Suitable resins for this technique include any liquid or solid TGMDA resins. Improved epoxy formulation proves useful as composite matrix resin, adhesive, or casting resin for applications on commercial and advanced aircraft.

  5. The Physical Mechanisms Responsible for the Weathering of Epoxy Resins and Glass Fibre Reinforced Expoxy Resins.

    Science.gov (United States)

    1980-10-01

    promise is that in which- the load transferred from resin to fibre is measured photoelastically. A microscope with rectified optics has improved our...an oven and added to the liquid epoxy resin prior to vigorous mixing and subsequent de-gassing under vacuum. The moulds were carefully cleaned and...dried, and warmed to approximately 500 C to aid in filling the mould to the desired level with the viscous resin . After gelling for 2 hours at 1000 C the

  6. 5-year clinical performance of resin composite versus resin modified glass ionomer restorative system in non-carious cervical lesions

    DEFF Research Database (Denmark)

    Franco, Eduardo Batista; Benetti, Ana Raquel; Ishikiriama, Sérgio Kiyoshi

    2006-01-01

    To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions.......To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions....

  7. Effect of surface treatments on the bond strength between composite resin and acrylic resin denture teeth.

    Science.gov (United States)

    Vergani, C E; Machado, A L; Giampaolo, E T; Pavarina, A C

    2000-01-01

    This investigation studied the effects of 3 surface treatments on the shear bond strength of a light-activated composite resin bonded to acrylic resin denture teeth. The occlusal surfaces of 30 acrylic resin denture teeth were ground flat with up to 400-grit silicon carbide paper. Three different surface treatments were evaluated: (1) the flat ground surfaces were primed with methyl methacrylate (MMA) monomer for 180 seconds; (2) light-cured adhesive resin was applied and light polymerized according to the manufacturer's instructions; and (3) treatment 1 followed by treatment 2. The composite resin was packed on the prepared surfaces using a split mold. The interface between tooth and composite was loaded at a cross-head speed of 0.5 mm/min until failure. Analysis of variance indicated significant differences between the surface treatments. Results of mean comparisons using Tukey's test showed that significantly higher shear bond strengths were developed by bonding composite resin to the surfaces that were previously treated with MMA and then with the bonding agent when compared to the other treatments. Combined surface treatment of MMA monomer followed by application of light-cured adhesive resin provided the highest shear bond strength between composite resin and acrylic resin denture teeth.

  8. Durability of adhesion between feldspathic ceramic and resin cements: effect of adhesive resin, polymerization mode of resin cement, and aging.

    Science.gov (United States)

    Vanderlei, Aleska; Passos, Sheila Pestana; Özcan, Mutlu; Bottino, Marco Antonio; Valandro, Luiz Felipe

    2013-04-01

    Adhesive cementation is an important step for restorations made of feldspathic ceramic as it increases the strength of such materials. Incorrect selection of the adhesive resin and the resin cement to adhere to the ceramic surface and their durability against aging can affect the adhesion between these materials and the clinical performance. This study evaluated the effect of adhesive resins with different pHs, resin cements with different polymerization modes, and aging on the bond strength to feldspathic ceramic. One surface of feldspathic ceramic blocks (VM7) (N = 90) (6.4 × 6.4 × 4.8 mm(3) ) was conditioned with 10% hydrofluoric acid for 20 seconds, washed/dried, and silanized. Three adhesive resins (Scotchbond Multi-Purpose Plus [SBMP], pH: 5.6; Single Bond [SB], pH: 3.4; and Prime&Bond NT [NT], pH: 1.7) were applied on the ceramic surfaces (n = 30 per adhesive). For each adhesive group, three resin cements with different polymerization modes were applied (n = 10 per cement): photo-polymerized (Variolink II base), dual polymerized (Variolink II base + catalyst), and chemically polymerized (C&B). The bonded ceramic blocks were stored in water (37°C) for 24 hours and sectioned to produce beam specimens (cross-sectional bonded area: 1 ± 0.1 mm(2) ). The beams of each block were randomly divided into two conditions: Dry, microtensile test immediately after cutting; TC, test was performed after thermocycling (12,000×, 5°C to 55°C) and water storage at 37°C for 150 days. Considering the three factors of the study (adhesive [3 levels], resin cement [3 levels], aging [2 levels]), 18 groups were studied. The microtensile bond strength data were analyzed using 3-way ANOVA and Tukey's post hoc test (α= 0.05). Adhesive resin type (p cement affected the mean bond strength (p= 0.0003) (3-way ANOVA). The NT adhesive associated with the chemically polymerized resin cement in both dry (8.8 ± 6.8 MPa) and aged conditions (6.9 ± 5.9 MPa) presented statistically lower

  9. Combining resin composite bonding and enamel microabrasion.

    Science.gov (United States)

    Croll, T P

    1996-10-01

    Some teeth can best be treated by a combination of enamel microabrasion and resin composite bonding. This article outlines a protocol for treating patients with such teeth and documents one case, showing 5-year results.

  10. Volumetric polymerization shrinkage of contemporary composite resins

    Directory of Open Access Journals (Sweden)

    Halim Nagem Filho

    2007-10-01

    Full Text Available The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill Magic, Alert, and Solitaire to determine whether there are differences among these materials. The tests were conducted with precision of 0.1 mg. The volumetric shrinkage was measured by hydrostatic weighing before and after polymerization and calculated by known mathematical equations. One-way ANOVA (a or = 0.05 was used to determine statistically significant differences in volumetric shrinkage among the tested composite resins. Suprafill (1.87±0.01 and Definite (1.89±0.01 shrank significantly less than the other composite resins. SureFil (2.01±0.06, Filtek Z250 (1.99±0.03, and Fill Magic (2.02±0.02 presented intermediate levels of polymerization shrinkage. Alert and Solitaire presented the highest degree of polymerization shrinkage. Knowing the polymerization shrinkage rates of the commercially available composite resins, the dentist would be able to choose between using composite resins with lower polymerization shrinkage rates or adopting technical or operational procedures to minimize the adverse effects deriving from resin contraction during light-activation.

  11. Resin adhesion to carious dentin.

    Science.gov (United States)

    Yoshiyama, Masahiro; Tay, Franklin R; Torii, Yasuhiro; Nishitani, Yoshihiro; Doi, Junichi; Itou, Kousuke; Ciucchi, Bernard; Pashley, David H

    2003-02-01

    To investigate the microtensile bond strength (microTBS) of a self-etching priming adhesive system to normal, caries-affected and caries-infected dentin, and to observe the ultrastructure of the resin-dentin interface by transmission electron microscopy (TEM). Twelve extracted human molar teeth with deep occlusal caries were stained with caries detector solution and ground flat occlusally. The red-stained soft dentin was classified as caries-infected. The surrounding discolored dentin was classified as caries-affected dentin. The surrounding normal dentin served as a control. The entire flat surface was bonded with Clearfil Liner Bond 2V (CV) and covered with resin composite to form a composite crown 5 mm high. One day later the specimens were serially sectioned vertically into multiple slabs 0.8 mm thick. Under microscopic observation, the specimens were divided into normal or caries-infected or caries-affected dentin. These regions were isolated by cutting away the remaining dentin to form hour-glass shapes with the smallest surface area at the test site. After measuring the areas, the specimens were fixed to a microtensile tester and pulled under tension to failure. Additional slabs that were not used for bond strength tests were processed for TEM. Bond strength data were analyzed by Kruskal-Wallis one-way ANOVA and Student-Newman-Keuls multiple comparisons. The microTBS of CV to normal, caries-affected and caries-infected dentin were 45 +/- 10 MPa, 30 +/- 10 MPa, 10 +/- 5 MPa, respectively. TEM images showed that CV formed thin hybrid layers that were less than 1 microm thick in normal dentin, but that were between 6-8 microm thick in caries-affected dentin. Bacteria were only sparsely observed in the dentin tubules of bonded caries-affected dentin. However, in caries-infected dentin, an unusual interface was seen in which carious bacteria within disorganized non-banded collagen fibrils could be seen embedded by the adhesive. The hybrid layer in caries

  12. Imide modified epoxy matrix resins

    Science.gov (United States)

    Scola, D. A.

    1984-01-01

    The results of a program designed to develop tough imide modified epoxy resins cured by bisimide amine (BIA) hardeners are described. State-of-the-art epoxides MY720 and DER383 were used, and four bismide amines were evaluated. These were the BIA's derived from the 6F anhydride (4,4'-(hexafluoroisopropylidene) bis(phthalic anhydride) and the diamines 3,3'-diaminodiphynyl sulfone, 4,4'-oxygianiline, 4,4'-methylene dianiline, and 1,12-dodecane diamine. A key intermediate, designated 6F anhydride, is required for the synthesis of the bisimide amines. Reaction parameters to synthesize a precursor to the 6F anhydride (6FHC) in high yields were investigated. The catalyst trifluoromethane sulfonic acid was studied. Although small scale runs yielded the 6FHC in 50 percent yield, efforts to ranslate these results to a larger scale synthesis gave the 6FHC in only 9 percent yield. Results show that the concept of using bisimide amine as curing agents to improve the toughness properties of epoxies is valid.

  13. Apical microleakage of epoxy resin and methacrylate resin-based sealer with continuous wave obturation technique

    Directory of Open Access Journals (Sweden)

    Haslinda Haslinda

    2016-04-01

    Full Text Available The aim of this research was to determine the microleakage apical sealer based on epoxy resin and methacrylate resin with continuous wave obturation technique.Thirty  permanent  lateral incisors were selected at random and  divided into 3 groups (N=10, namely AH Plus obturator group (epoxy resin, EndoREZ group (methacrylate resin, and negative control. The samples were decoronated, root canal preparation, then kept in incubator of 37°C for 72 hours. Sample were coated with nail varnish then immersed in methylene blue for 48 hours. The samples were washed with distilled water, dried and nail varnish removed. The samples were clearing. Penetration was measured using microscope and given score 0-4. Measurements were analyzed statistically. By using Kruskal Wallis test and Mann Whitney test, there is no significant difference between the apical microleakage of the the epoxy resin root canal sealer with methacrylate root canal sealer based (p>0,05. It means that the apical microleakage of the epoxy resin root canal sealer based comparable with merhacrylate root canal sealer based. It was concluded that the apical microleakage of epoxy resin based sealer does not different to the methacrylate resin based sealer

  14. Bond strength of resin-resin interfaces contaminated with saliva and submitted to different surface treatments

    Directory of Open Access Journals (Sweden)

    Adilson Yoshio Furuse

    2007-12-01

    Full Text Available The purpose of this study was to investigate the effect of different surface treatments on shear bond strength of saliva-contaminated resin-resin interfaces. Flat resin surfaces were fabricated. In the control group, no contamination or surface treatment was performed. The resin surfaces of the experimental groups were contaminated with saliva and air-dried, and then submitted to: (G1 rinsing with water and drying; (G2 application of an adhesive system; (G3 rinsing and drying, abrasion with finishing disks, etching and application of adhesive system; (G4 rinsing and drying, etching, application of silane and adhesive system. Resin cylinders were placed over the treated surfaces. The specimens were stored in water or ethanol. Shear bond strength tests were performed and the mode of failure was evaluated. Data were submitted to two-way ANOVA and Dunnett T3 test. Contamination of resin-resin interfaces with saliva significantly reduced shear strength, especially after prolonged storage (p<0.05. Similar values to the original bond strength were obtained after abrasion and application of adhesive (G3 or etching and application of silane and adhesive (G4. If contamination occurs, a surface treatment is required to guarantee an adequate interaction between the resin increments.

  15. Bond strength of resin-resin interfaces contaminated with saliva and submitted to different surface treatments

    DEFF Research Database (Denmark)

    Furuse, Adilson Yoshio; da Cunha, Leonardo Fernandes; Benetti, Ana Raquel

    2007-01-01

    of silane and adhesive system. Resin cylinders were placed over the treated surfaces. The specimens were stored in water or ethanol. Shear bond strength tests were performed and the mode of failure was evaluated. Data were submitted to two-way ANOVA and Dunnett T3 test. Contamination of resin...

  16. Effect of resin thickness on the microhardness and optical properties of bulk-fill resin composites.

    Science.gov (United States)

    Kim, Eun-Ha; Jung, Kyoung-Hwa; Son, Sung-Ae; Hur, Bock; Kwon, Yong-Hoon; Park, Jeong-Kil

    2015-05-01

    This study evaluated the effects of the resin thickness on the microhardness and optical properties of bulk-fill resin composites. Four bulk-fill (Venus Bulk Fill, Heraeus Kulzer; SDR, Dentsply Caulk; Tetric N-Ceram Bulk Fill, Ivoclar vivadent; SonicFill, Kerr) and two regular resin composites (Charisma flow, Heraeus Kulzer; Tetric N-Ceram, Ivoclar vivadent) were used. Sixty acrylic cylindrical molds were prepared for each thickness (2, 3 and 4 mm). The molds were divided into six groups for resin composites. The microhardness was measured on the top and bottom surfaces, and the colors were measured using Commission Internationale d'Eclairage (CIE) L (*) a (*) b (*) system. Color differences according to the thickness and translucency parameters and the correlations between the microhardness and translucency parameter were analyzed. The microhardness and color differences were analyzed by ANOVA and Scheffe's post hoc test, and a student t-test, respectively. The level of significance was set to α = 0.05. The microhardness decreased with increasing resin thickness. The bulk-fill resin composites showed a bottom/top hardness ratio of almost 80% or more in 4 mm thick specimens. The highest translucency parameter was observed in Venus Bulk Fill. All resin composites used in this study except for Venus Bulk Fill showed linear correlations between the microhardness and translucency parameter according to the thickness. Within the limitations of this study, the bulk-fill resin composites used in this study can be placed and cured properly in the 4 mm bulk.

  17. Shear bond strength between alumina substrate and prosthodontic resin composites with various adhesive resin systems.

    Science.gov (United States)

    AlJehani, Yousef A; Baskaradoss, Jagan K; Geevarghese, Amrita; AlShehry, Marey A; Vallittu, Pekka K

    2015-05-02

    With the increase in demand for cosmetics and esthetics, resin composite restorations and all-ceramic restorations have become an important treatment alternative. Taking into consideration the large number of prosthodontic and adhesive resins currently available, the strength and durability of these materials needs to be evaluated. This laboratory study presents the shear bond strengths of a range of veneering resin composites bonded to all-ceramic core material using different adhesive resins. Alumina ceramic specimens (Techceram Ltd, Shipley, UK) were assigned to three groups. Three types of commercially available prosthodontic resin composites [BelleGlass®, (BG, Kerr, CA, USA), Sinfony® (SF, 3 M ESPE, Dental Products, Germany), and GC Gradia® (GCG, GC Corp, Tokyo, Japan)] were bonded to the alumina substrate using four different adhesive resins. Half the specimens per group (N = 40) were stored dry for 24 hours, the remaining were stored for 30 days in water. The bonding strength, so-called shear bond strengths between composite resin and alumina substrate were measured. Data were analysed statistically and variations in bond strength within each group were additionally evaluated by calculating the Weibull modulus. Bond strengths were influenced by the brand of prosthodontic resin composites. Shear bond strengths of material combinations varied from 24.17 ± 3.72-10.15 ± 3.69 MPa and 21.20 ± 4.64-7.50 ± 4.22 at 24 h and 30 days, respectively. BG resin composite compared with the other resin composites provided the strongest bond with alumina substrate (p < 0.01). SF resin composite was found to have a lower bond strength than the other composites. The Weibull moduli were highest for BG, which was bonded by using Optibond Solo Plus adhesive resin at 24 h and 30 days. There was no effect of storage time and adhesive brand on bond strength. Within the limitations of this study, the shear bond strengths of composite resins to alumina substrate are related to

  18. Bulk-filled posterior resin restorations based on stress-decreasing resin technology

    DEFF Research Database (Denmark)

    van Dijken, Jan W.V.; Pallesen, Ulla

    2017-01-01

    This randomized study evaluated a flowable resin composite bulk-fill technique in posterior restorations and compared it intraindividually with a conventional 2-mm resin composite layering technique over a 6-yr follow-up period. Thirty-eight pairs of Class II restorations and 15 pairs of Class I...... restorations were placed in 38 adults. In all cavities a single-step self-etch adhesive (Xeno V) was applied. In the first cavity of each pair, the flowable resin composite (SDR) was placed, in bulk increments of up to 4 mm. The occlusal part was completed with a layer of nanohybrid resin composite (Ceram X...... mono). In the second cavity of each pair, the hybrid resin composite was placed in 2-mm increments. The restorations were evaluated using slightly modified US Public Health Service (USPHS) criteria at baseline and then annually for a time period of 6 yr. After 6 yr, 72 Class II restorations and 26...

  19. Tc-99 Ion Exchange Resin Testing

    Energy Technology Data Exchange (ETDEWEB)

    Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

    2010-08-01

    Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

  20. Monomethacrylate co-monomers for dental resins.

    Science.gov (United States)

    Labella, R; Davy, K W; Lambrechts, P; Van Meerbeek, B; Vanherle, G

    1998-06-01

    Polymerisation shrinkage is widely recognised as a major drawback of resin based dental restoratives. Bis-GMA is often employed as the principal dimethacrylate monomer. Due to its high viscosity, Bis-GMA is normally mixed with large proportions of low viscosity glycol dimethacrylates. The purpose of this study was to determine whether the polymerisation shrinkage of Bis-GMA-based resins would be lower if alternative monomethacrylate co-monomers were used in place of conventional dimethacrylate co-monomers as viscosity modifiers. Conventional resins used were ethyleneglycol dimethacrylate and triethyleneglycol dimethacrylate; the alternative monofunctional co-monomers were tetrahydrofurfuryl methacrylate, hydroxypropyl methacrylate and isobornyl methacrylate. Model resins containing 54% mol/mol of co-monomer in Bis-GMA and 1% w/w of benzoyl peroxide as initiator were heat-cured at 70 degrees C for 8 h. Polymerisation shrinkage, degree of conversion and concentration of remaining methacrylate groups were calculated from density changes obtained gravimetrically. Other properties evaluated were Young's modulus, water uptake and viscosity of the monomer mixtures. The Bis-GMA-based resins exhibited lower shrinkage when mixed using the monomethacrylates rather than with conventional glycol dimethacrylates. Among the alternative co-monomers, tetrahydrofurfuryl methacrylate conferred the best balance of all measured properties.

  1. Ponderosa pine resin defenses and growth: metrics matter.

    Science.gov (United States)

    Hood, Sharon; Sala, Anna

    2015-11-01

    Bark beetles (Coleoptera: Curculionidae, Scolytinae) cause widespread tree mortality in coniferous forests worldwide. Constitutive and induced host defenses are important factors in an individual tree's ability to survive an attack and in bottom-up regulation of bark beetle population dynamics, yet quantifying defense levels is often difficult. For example, in Pinus spp., resin flow is important for resistance to bark beetles but is extremely variable among individuals and within a season. While resin is produced and stored in resin ducts, the specific resin duct metrics that best correlate with resin flow remain unclear. The ability and timing of some pine species to produce induced resin is also not well understood. We investigated (i) the relationships between ponderosa pine (Pinus ponderosa Lawson & C. Lawson) resin flow and axial resin duct characteristics, tree growth and physiological variables, and (ii) if mechanical wounding induces ponderosa pine resin flow and resin ducts in the absence of bark beetles. Resin flow increased later in the growing season under moderate water stress and was highest in faster growing trees. The best predictors of resin flow were nonstandardized measures of resin ducts, resin duct size and total resin duct area, both of which increased with tree growth. However, while faster growing trees tended to produce more resin, models of resin flow using only tree growth were not statistically significant. Further, the standardized measures of resin ducts, density and duct area relative to xylem area, decreased with tree growth rate, indicating that slower growing trees invested more in resin duct defenses per unit area of radial growth, despite a tendency to produce less resin overall. We also found that mechanical wounding induced ponderosa pine defenses, but this response was slow. Resin flow increased after 28 days, and resin duct production did not increase until the following year. These slow induced responses may allow

  2. Comparative study of resin sealant and resin modified glass ionomer as pit and fissure sealant

    Directory of Open Access Journals (Sweden)

    Shirin Malek

    2017-02-01

    Full Text Available The purpose of the present study was to compare the marginal integrity of resin modified glass ionomer cement with that of resin sealant, in vitro. Forty artificial pit and fissure cavities were prepared in occlusal surface of extracted premolar teeth by using ¼ round carbide bur. Cavities were condensed with artificial organic debris followed by cleaning with prophylaxis pumice brush and paste and then separated into two treatment groups. In Group A, 15 fissure cavities were sealed by resin sealant and in Group B, 15 fissure cavities were sealed by resin modified glass ionomer sealant. These specimens were subjected to thermo-cycling followed by dye penetration test. The remaining 5 cavities from each group were analyzed for debris score by the SEM. The results of the microleakage test showed that the efficacy of preventing microleakage of samples sealed by resin modified glass ionomer sealant was higher than the samples sealed by resin sealant. However, no significant differences were found. It can be concluded that use of resin modified glass ionomer sealant is a good alternative for sealing pits and fissures.

  3. The Creep of Laminated Synthetic Resin Plastics

    Science.gov (United States)

    Perkuhn, H

    1941-01-01

    The long-time loading strength of a number of laminated synthetic resin plastics was ascertained and the effect of molding pressure and resin content determined. The best value was observed with a 30 to 40 percent resin content. The long-time loading strength also increases with increasing molding pressure up to 250 kg/cm(exp 2); a further rise in pressure affords no further substantial improvement. The creep strength is defined as the load which in the hundredth hour of loading produces a rate of elongation of 5 X 10(exp -4) percent per hour. The creep strength values of different materials were determined and tabulated. The effect of humidity during long-term tests is pointed out.

  4. Investigations of toughening mechanisms of epoxy resins

    Science.gov (United States)

    Koenig, T.

    1986-01-01

    Composite material technology was applied to the solid rocket booster by the development of a carbon filament-epoxy resin case which yields a net increase of 4000 lbs. in payload in the shuttle. The question of reusability of the new composite tanks has not yet been answered and will depend on the toughness of the matrix resin. The present study was aimed at providing conditions whereby test specimens of the epoxy resin (EPON/85) and curing agents of systematically varied structures could be produced in a controlled manner. Three sets of conditions were found that might allow the isolation of the structural effects on toughness from the cure effects. The kinetic methods leading to the determination of these conditions are described.

  5. Fluorinated Alkyl Ether Epoxy Resin Compositions and Applications Thereof

    Science.gov (United States)

    Wohl, Christopher J. (Inventor); Connell, John W. (Inventor); Smith, Joseph G. (Inventor); Siochi, Emilie J. (Inventor); Gardner, John M. (Inventor); Palmieri, Frank M. (Inventor)

    2017-01-01

    Epoxy resin compositions prepared using amino terminated fluoro alkyl ethers. The epoxy resin compositions exhibit low surface adhesion properties making them useful as coatings, paints, moldings, adhesives, and fiber reinforced composites.

  6. 76 FR 8774 - Granular Polytetrafluoroethylene Resin From Japan

    Science.gov (United States)

    2011-02-15

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Granular Polytetrafluoroethylene Resin From Japan AGENCY: United States International Trade... polytetrafluoroethylene resin from Japan would be likely to lead to continuation or recurrence of material injury. On...

  7. Development of 3-methoxy-4-benzyloxybenzyl alcohol (MBBA) resin ...

    Indian Academy of Sciences (India)

    step sequence under microwave irradiation involving the reaction of commercially available Merrifield resin with vanillin, followed by reduction with sodium borohydride. MBBA resin was treated with bromides in the presence of sodium hydride to ...

  8. Composite resin fillings and inlays: An 11-year evaluation

    DEFF Research Database (Denmark)

    Pallesen, U.; Qvist, V.

    2003-01-01

    Clinical trial, composite resin, direct restorations, indirect restorations, long-term behaviour, posterior teeth......Clinical trial, composite resin, direct restorations, indirect restorations, long-term behaviour, posterior teeth...

  9. Evaluation of Some Anionic Exchange Resins as Potential Tablet ...

    African Journals Online (AJOL)

    . The thickness and ... synthesis of the resins via polymerization [13]. In previous studies, these resins were pharmaceutically ..... classes of superdisintegrants in promoting aspirin tablet disintegration and dissolution. AAPS. PharmSciTech ...

  10. Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite.

    Science.gov (United States)

    Hsu, Sheng-Hao; Chen, Rung-Shu; Chang, Yuan-Ling; Chen, Min-Huey; Cheng, Kuo-Chung; Su, Wei-Fang

    2012-11-01

    Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100 nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility

  11. The influence of resin flexural modulus on the magnitude of ceramic strengthening.

    LENUS (Irish Health Repository)

    Fleming, Garry J P

    2012-07-01

    The aim was to determine the magnitude of ceramic resin-strengthening with resin-based materials with varying flexural moduli using a regression technique to assess the theoretical strengthening at a \\'zero\\' resin-coating thickness. The hypothesis tested was that experimentally, increasing resin flexural modulus results in increased resin-strengthening observed at a theoretical \\'zero\\' resin-coating thickness.

  12. Synthesis of a boron modified phenolic resin

    Directory of Open Access Journals (Sweden)

    Aparecida M. Kawamoto

    2010-08-01

    Full Text Available Phenolic resin has long been used as matrix for composites mainly because of its flame retardant behavior and high char yield after pyrolysis, which results in a self supporting structure. The addition of ceramic powders, such as SiC and B4C, as fillers to the phenolic resin, results in better thermo-oxidative stability, but as drawbacks, it has poor homogeneity, adhesion and processing difficulties during molding of the composites. The addition of single elements, such as boron, silicon and phosphorus in the main backbone of the thermo-set resin is a new strategy to obtain special high performance resins, which results in higher mechanical properties, avoiding the drawbacks of simply adding fillers, which results in enhanced thermo-oxidative stability compared to conventional phenol-formaldehyde resins. Therefore, the product can have several applications, including the use as ablative thermal protection for thermo-structural composites. This work describes the preparation of a boron-modified phenolic resin (BPR using salicyl alcohol and boric acid. The reaction was performed in refluxing toluene for a period of four hours, which produced a very high viscosity amber resin in 90% yield.The final structure of the compound, the boric acid double, substituted at the hydroxyl group of the aromatic ring, was determined with the help of the Infrared Spectroscopy, ¹H-NMR, TGA-DSC and boron elemental analysis. The absorption band of the group B-O at 1349 cm ˉ¹ can be visualized at the FT-IR spectrum. ¹H-NMR spectra showed peaks at 4.97-5.04 ppm and 3.60-3.90 ppm assigned to belong to CH2OH groups from the alcohol. The elemental analysis was also performed for boron determination.The product has also been tested in carbon and silicon fibers composite for the use in thermal structure. The results of the tests showed composites with superior mechanical properties when compared with the conventional phenolic resin.

  13. Understanding of the color in composite resin

    Directory of Open Access Journals (Sweden)

    Jeong-Won Park

    2011-07-01

    Full Text Available In clinic, esthetic restoration of a defective natural tooth with composite resin is challenging procedure and needs complete understanding of the color of tooth itself and materials used. The optical characteristics of the composites are different because the chemical compositions and microstructures are not same. This review provided basic knowledge of the color and the color measurement devices, and analyze the color of the natural tooth. Further, the accuracy of the shade tab, color of the composite resins before and after curing, effect of the water, food and bleaching agent, and translucency, opalescence, and fluorescence effects were evaluated.

  14. Wood ants protect their brood with tree resin

    OpenAIRE

    Brütsch, T.; Chapuisat, M

    2014-01-01

    Social insects use multiple lines of collective defences to combat pathogens. One example of a behav- ioural group defence is the use of antimicrobial plant compounds to disinfect the nest. Indeed, wood ants collect coniferous tree resin, and the presence of resin in their nest protects them against fungal and bacterial pathogens. Many questions remain on the mechanisms of resin use, including which factors elicit resin collection and placement within nests. Here, we investigated whether the ...

  15. Management of white spots: resin infiltration technique and microabrasion

    OpenAIRE

    Jeong-Hye Son; Bock Hur,; Hyeon-Cheol Kim,; Jeong-Kil Park

    2011-01-01

    This case report compared the effectiveness of resin infiltration technique (Icon, DMG) with microabrasion (Opalustre, Ultradent Products, Inc.) in management of white spot lesions. It demonstrates that although neither microabrasion nor resin infiltration technique can remove white spot lesions completely, resin infiltration technique seems to be more effective than microabrasion. Therefore resin infiltration technique can be chosen preferentially for management of white spot lesions and cau...

  16. Management of white spots: resin infiltration technique and microabrasion

    Directory of Open Access Journals (Sweden)

    Jeong-Hye Son

    2011-01-01

    Full Text Available This case report compared the effectiveness of resin infiltration technique (Icon, DMG with microabrasion (Opalustre, Ultradent Products, Inc. in management of white spot lesions. It demonstrates that although neither microabrasion nor resin infiltration technique can remove white spot lesions completely, resin infiltration technique seems to be more effective than microabrasion. Therefore resin infiltration technique can be chosen preferentially for management of white spot lesions and caution should be taken for case selection.

  17. Curing reaction of bisphenol-A based benzoxazine with cyanate ester resin and the properties of the cured thermosetting resin

    Directory of Open Access Journals (Sweden)

    H. Kimura

    2011-12-01

    Full Text Available Curing reaction of bisphenol-A based benzoxazine with cyanate ester resin and the properties of the cured thermosetting resin were investigated. The cure behavior of benzoxazine with cyanate ester resin was monitored by model reaction using nuclear magnetic resonance (NMR. As a result of the model reaction, the ring opening reaction of benzoxazine ring and thermal self-cyclotrimerization of cyanate ester group occurred, and then the phenolic hydoroxyl group generated by the ring opening reaction of benzoxazine ring co-reacted with cyanate ester group. The properties of the cured thermosetting resin were estimated by mechanical properties, electrical resistivity, water resistance and heat resistance. The cured thermosetting resin from benzoxazine and cyanate ester resin showed good heat resistance, high electrical resistivity and high water resistance, compared with the cured thermosetting resin from benzoxazine and epoxy resin.

  18. Chemical composition and palaeobotanical origin of Miocene resins ...

    Indian Academy of Sciences (India)

    tion varies with resin type which together with a structural resistance to diagenetic ... ionization energy of 70eV and a source tempera- ture of 260. ◦. C. Full scan mass ... fossil resin sample from Sindhudurg Formation, Konkan Coast, western India; (b) Miocene fossil resin sample from Warkallai. Group, Kerala Coast, western ...

  19. 21 CFR 177.2420 - Polyester resins, cross-linked.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyester resins, cross-linked. 177.2420 Section... as Components of Articles Intended for Repeated Use § 177.2420 Polyester resins, cross-linked. Cross-linked polyester resins may be safely used as articles or components of articles intended for repeated...

  20. 21 CFR 872.3770 - Temporary crown and bridge resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Temporary crown and bridge resin. 872.3770 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a material, such as...

  1. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for the...

  2. 21 CFR 173.10 - Modified polyacrylamide resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Modified polyacrylamide resin. 173.10 Section 173... CONSUMPTION Polymer Substances and Polymer Adjuvants for Food Treatment § 173.10 Modified polyacrylamide resin. Modified polyacrylamide resin may be safely used in food in accordance with the following prescribed...

  3. Resin impregnation of cellulose nanofibril films facilitated by water swelling

    Science.gov (United States)

    Yan Qing; Ronald Sabo; Zhiyong Cai; Yiqiang Wu

    2013-01-01

    Flexible composite films were produced by impregnating aqueous phenol formaldehyde (PF) resin into water-swollen cellulose nanofibril (CNF) films. CNF films were prepared using a pressurized filtration method in combination with freeze drying. The freeze-dried films were swollen with water then impregnated with PF resin by soaking in aqueous resin solutions of varying...

  4. 40 CFR 721.5908 - Modified phenolic resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified phenolic resin (generic). 721... Substances § 721.5908 Modified phenolic resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as modified phenolic resin (PMN P...

  5. 76 FR 39896 - Granular Polytetrafluoroethylene Resin From Italy

    Science.gov (United States)

    2011-07-07

    ... COMMISSION Granular Polytetrafluoroethylene Resin From Italy Determination On the basis of the record \\1... antidumping duty order on granular polytetrafluoroethylene resin from Italy would be likely to lead to... Granular Polytetrafluoroethylene Resin from Italy: Investigation No. 731-TA-385 (Third Review). By order of...

  6. 21 CFR 172.215 - Coumarone-indene resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Coumarone-indene resin. 172.215 Section 172.215... CONSUMPTION Coatings, Films and Related Substances § 172.215 Coumarone-indene resin. The food additive coumarone-indene resin may be safely used on grapefruit, lemons, limes, oranges, tangelos, and tangerines in...

  7. Glass Fiber Resin Composites and Components at Arctic Temperatures

    Science.gov (United States)

    2015-06-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited GLASS FIBER RESIN ...3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE GLASS FIBER RESIN COMPOSITES AND COMPONENTS AT ARCTIC TEMPERATURES 5...dependent on the reaction between the fiber and the resin , but little research has been conducted that was geared toward naval applications at arctic

  8. 40 CFR 721.3135 - Phosphorous modified epoxy resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphorous modified epoxy resin... Specific Chemical Substances § 721.3135 Phosphorous modified epoxy resin (generic). (a) Chemical substance... phosphorous modified epoxy resin (PMNs P-00-992 and P-01-471) is subject to reporting under this section for...

  9. 21 CFR 872.3820 - Root canal filling resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Root canal filling resin. 872.3820 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material, such as methylmethacrylate, intended...

  10. 21 CFR 872.3690 - Tooth shade resin material.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tooth shade resin material. 872.3690 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of materials such as bisphenol-A glycidyl...

  11. 21 CFR 872.3310 - Coating material for resin fillings.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Coating material for resin fillings. 872.3310... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to the...

  12. 21 CFR 573.120 - Acrylamide-acrylic acid resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573.120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin...

  13. Treatment of White Spot Lesions with Icon (Resin Infiltration)

    Science.gov (United States)

    2017-03-23

    FROM: 59 MDW/SGVU SUBJECT: Professional Presentation Approval 8 MAR2017 1. Your paper, entitled T reatment of White Spot Lesions with Icon ( Resin ... Resin Infiltration) 6. TITLE OF MATERIAL TO BE PUBLISHED OR PRESENTED: Treatment of White Spot lesions with Icon ( Resin In filtration) 7. FUNDING

  14. 40 CFR 721.5905 - Modified phenolic resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified phenolic resin (generic). 721... Substances § 721.5905 Modified phenolic resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a modified phenolic resin (PMN...

  15. 40 CFR 721.9499 - Modified silicone resin.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified silicone resin. 721.9499... Substances § 721.9499 Modified silicone resin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a modified silicone resin (PMN P-96-1649) is...

  16. 40 CFR 721.4380 - Modified hydrocarbon resin.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified hydrocarbon resin. 721.4380... Substances § 721.4380 Modified hydrocarbon resin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a modified hydrocarbon resin (P-91-1418) is...

  17. 40 CFR 721.2755 - Cycloaliphatic epoxy resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Cycloaliphatic epoxy resin (generic... Substances § 721.2755 Cycloaliphatic epoxy resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as cycloaliphatic epoxy resin (PMN...

  18. 40 CFR 721.2673 - Aromatic epoxide resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic epoxide resin (generic). 721... Substances § 721.2673 Aromatic epoxide resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic epoxide resin (PMN P...

  19. 75 FR 67105 - Granular Polytetrafluoroethylene Resin From Italy and Japan

    Science.gov (United States)

    2010-11-01

    ... COMMISSION Granular Polytetrafluoroethylene Resin From Italy and Japan AGENCY: United States International... granular polytetrafluoroethylene resin from Italy and Japan. SUMMARY: The Commission hereby gives notice... polytetrafluoroethylene resin from Italy and Japan would be likely to lead to continuation or recurrence of material...

  20. 21 CFR 173.40 - Molecular sieve resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Molecular sieve resins. 173.40 Section 173.40 Food... Polymer Substances and Polymer Adjuvants for Food Treatment § 173.40 Molecular sieve resins. Molecular...) The molecular sieve resins consist of purified dextran having an average molecular weight of 40,000...

  1. 21 CFR 181.32 - Acrylonitrile copolymers and resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylonitrile copolymers and resins. 181.32 Section... Ingredients § 181.32 Acrylonitrile copolymers and resins. (a) Acrylonitrile copolymers and resins listed in this section, containing less than 30 percent acrylonitrile and complying with the requirements of...

  2. 21 CFR 176.110 - Acrylamide-acrylic acid resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylamide-acrylic acid resins. 176.110 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.110 Acrylamide-acrylic acid resins. Acrylamide-acrylic acid resins may be safely used as components of articles intended for use in producing...

  3. 21 CFR 173.5 - Acrylate-acrylamide resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylate-acrylamide resins. 173.5 Section 173.5... CONSUMPTION Polymer Substances and Polymer Adjuvants for Food Treatment § 173.5 Acrylate-acrylamide resins. Acrylate-acrylamide resins may be safely used in food under the following prescribed conditions: (a) The...

  4. Molecular composition and paleobotanical origin of Eocene resin ...

    Indian Academy of Sciences (India)

    The molecular composition of fossil resins from early to middle Eocene coal from northeast India, has been analyzed for the first time to infer their paleobotanical source. The soluble component of fossil resin was analyzed using gas chromatography–mass spectrometry (GC–MS). The resin extracts are composed of ...

  5. 21 CFR 177.2355 - Mineral reinforced nylon resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Mineral reinforced nylon resins. 177.2355 Section... as Components of Articles Intended for Repeated Use § 177.2355 Mineral reinforced nylon resins. Mineral reinforced nylon resins identified in paragraph (a) of this section may be safely used as articles...

  6. Occupational asthma due to unheated polyvinylchloride resin dust.

    OpenAIRE

    Lee, H S; Yap, J; Wang, Y T; Lee, C S; Tan, K T; Poh, S C

    1989-01-01

    Polyvinylchloride (PVC) resins are widely used in industry. Asthma due to the thermal degradation products of PVC are well documented. In this first case of occupational asthma due to unheated PVC resin dust the patient was exposed to PVC resin dust during the mixing of chemicals used for making plastic seals for bottle caps.

  7. 21 CFR 177.2510 - Polyvinylidene fluoride resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyvinylidene fluoride resins. 177.2510 Section... as Components of Articles Intended for Repeated Use § 177.2510 Polyvinylidene fluoride resins. Polyvinylidene fluoride resins may be safely used as articles or components of articles intended for repeated use...

  8. Photosensitive filler minimizes internal stresses in epoxy resins

    Science.gov (United States)

    Dillon, J. N.

    1967-01-01

    Photosensitive filler is added to curable epoxy resins to minimize stress from internal shrinkage during curing or polymerization. Cinnamic acid resins and cinnamal ketones may be added in the amount of 1 to 3 percent by weight of the resin mixture.

  9. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Epoxy resin containing phosphorus... Specific Chemical Substances § 721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance... epoxy resin containing phosphorus (PMN P-00-912) is subject to reporting under this section for the...

  10. Low-melt Viscosity Polyimide Resins for Resin Transfer Molding (RTM) II

    Science.gov (United States)

    Chuang, Kathy C.; Criss, Jim M.; Mintz, Eric A.; Scheiman, Daniel A.; Nguyen, Baochau N.; McCorkle, Linda S.

    2007-01-01

    A series of polyimide resins with low-melt viscosities in the range of 10-30 poise and high glass transition temperatures (Tg s) of 330-370 C were developed for resin transfer molding (RTM) applications. These polyimide resins were formulated from 2,3,3 ,4 -biphenyltetracarboxylic dianhydride (a-BPDA) with 4-phenylethynylphthalic anhydride endcaps along with either 3,4 - oxyaniline (3,4 -ODA), 3,4 -methylenedianiline, (3,4 -MDA) or 3,3 -methylenedianiline (3,3 -MDA). These polyimides had pot lives of 30-60 minutes at 260-280 C, enabling the successful fabrication of T650-35 carbon fiber reinforced composites via RTM process. The viscosity profiles of the polyimide resins and the mechanical properties of the polyimide carbon fiber composites will be discussed.

  11. Facile synthesis of hypercrosslinked resins via chloromethylation ...

    Indian Academy of Sciences (India)

    Administrator

    Facile synthesis of hypercrosslinked resins via chloromethylation and continuous condensation of simple aryl molecules. XIAOYAN ZHANG, QIU JIN, LIBO DAI and SIGUO YUAN*. School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001, P.R. China. MS received 11 January 2010; revised 17 ...

  12. Evaluation of resins for use in brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Luiz Claudio F.M. Garcia; Ferraz, Wilmar Barbosa; Chrcanovic, Bruno Ramos; Santos, Ana Maria M., E-mail: ferrazw@cdtn.b, E-mail: amms@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    Brachytherapy is an advanced cancer treatment where radioactive seeds or sources are placed near or directly into the tumor thus reducing the radiation exposure in the surrounding healthy tissues. Prostate cancer can be treated with interstitial brachytherapy in initial stage of the disease in which tiny radioactive seeds with cylindrical geometry are used. Several kinds of seeds have been developed in order to obtain a better dose distribution around them and with a lower cost manufacturing. These seeds consist of an encapsulation, a radionuclide carrier, and X-ray marker. Among the materials that have potential for innovation in the construction of seeds, biocompatible resins appear as an important option. In this paper, we present some characterization results with Fourier transform infrared spectroscopic (FTIR) and ultraviolet-visible spectroscopy (UV-vis) performed on two types of resins in which curing temperatures for each one were varied as also the results of coatings with these resins under titanium substrates. Interactions of these resins in contact with the simulated body fluid were evaluated by atomic force microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. (author)

  13. Carbohydrate modified phenol-formaldehyde resins

    Science.gov (United States)

    Anthony H. Conner; Linda F. Lorenz

    1986-01-01

    For adhesive self-sufficiency, the wood industry needs new adhesive systems in which all or part of the petroleum-derived phenolic component is replaced by a renewable material without sacrificing high durability or ease of bonding. We tested the bonding of wood veneers, using phenolic resins in which part of the phenol-formaldehyde was replaced with carbohydrates. Our...

  14. Restoration of traumatized teeth with resin composites

    DEFF Research Database (Denmark)

    Pallesen, Ulla; van Dijken, Jan WV

    2017-01-01

    For a long time, the primary choice for initial restoration of a crown-fractured front tooth has been resin composite material. The restoration can in most cases be performed immediately after injury if there is no sign of periodontal injury. The method’s adhesive character is conservative to too...

  15. Triterpenes from the resin of Boswellia neglecta

    Directory of Open Access Journals (Sweden)

    Aman Dekebo

    2002-06-01

    Full Text Available The resin of Boswellia neglecta yielded four triterpenes canaric acid, α-amyrin, α-amyrone and epi-α-amyrin. Canaric acid and epi-α-amyrin are isolated here for the first time from the family Burseraceae. The compounds were identified using 1D and 2D NMR techniques.

  16. Extended Resin Composite Restorations: Techniques and Procedures

    NARCIS (Netherlands)

    Loomans, B.A.C.; Hilton, T.

    2016-01-01

    This article gives an overview of the state of the art of different restorative treatment procedures and techniques needed for placing extended posterior resin composite restorations. Clinical aspects related to the procedure are discussed and reviewed based on the current literature, such as the

  17. 21 CFR 177.2440 - Polyethersulfone resins.

    Science.gov (United States)

    2010-04-01

    ... percent acetic acid in distilled water, and n-heptane. (Note: In testing the finished food-contact article...) resins (CAS Reg. No. 25667-42-9), which have a minimum number average molecular weight of 16,000. (2) 1,1... molecular weight of 26,000. (3) In paragraphs (a)(1) and (a)(2) of this section, the minimum number average...

  18. Resin phantoms as skin simulating layers

    CSIR Research Space (South Africa)

    Karsten, AE

    2011-07-01

    Full Text Available on the efficiency of Photodynamic Therapy (PDT) treatment. Two resin based solid phantoms were prepared to simulate two different skin types. Cells were prepared and PDT treatment were done on cells with and without the phantoms, by keeping the total dose delivered...

  19. Triterpenes from the resin of Boswellia neglecta

    African Journals Online (AJOL)

    Boswellia neglecta S. Moore (Burseraceae) is found in Bale, Gamo Gofa, Hararghe and Sidamo. (Ethiopia) and also in neighbouring countries such as Kenya, Somalia, Tanzania and Uganda [1]. The plant produces aromatic resins used widely as incense known as “Dakara” (Oromifa),. "Borena Etan" (Amharic) or "Borena ...

  20. (GSA) resin for removal and recovery o

    African Journals Online (AJOL)

    2011-05-30

    May 30, 2011 ... The adsorption of different metal ions on GSA resin follows the order: Cu2+ > Fe2+ > Zn2+ > Cd2+ > Pb2+. The adsorbency of different metal ... Water pollution caused by toxic metal ions from various industrial effluents has ..... midazolylazo group and its use in the separation of heavy metals. Talanta 48 (5) ...

  1. Resin diffusion through demineralized dentin matrix

    Directory of Open Access Journals (Sweden)

    CARVALHO Ricardo M.

    1999-01-01

    Full Text Available This paper has focused on the factors that may affect the permeability of adhesive resins into the demineralized dentin matrix during the development of the bonding process. The effects of surface moisture are discussed respectively to the adhesive systems, and the problems related to incomplete hybrid layer formation presented.

  2. 21 CFR 177.1500 - Nylon resins.

    Science.gov (United States)

    2010-04-01

    .... (b) Specifications: Nylon resins Specific gravity Melting point(degrees Fahrenheit) Solubilityin boiling 4.2N HC1 Viscosity No.(mL/g) Maximum extractable fractionin selected solvents (expressed in... film is intended to contact all foods except those containing more than 8 percent ethanol under...

  3. 21 CFR 177.1580 - Polycarbonate resins.

    Science.gov (United States)

    2010-04-01

    ... condensation of 4,4′-iso-propylidenediphenol and carbonyl chloride to which may have been added certain...′-iso-propylidenediphenol with molten diphenyl carbonate in the presence of the disodium salt of 4,4... optional adjuvant substances required in the production of resins produced by the methods described in...

  4. 21 CFR 177.1556 - Polyaryletherketone resins.

    Science.gov (United States)

    2010-04-01

    ... solvents: Distilled water, 50 percent (by volume) ethyl alcohol in distilled water, 3 percent acetic acid... molecular weight of 20,000 grams per mole, as determined by light scattering measurements in sulfuric acid... production of such basic resins. These adjuvants may include substances used in accordance with § 174.5 of...

  5. Epoxy resins produce improved plastic scintillators

    Science.gov (United States)

    Markley, F. W.

    1967-01-01

    Plastic scintillator produced by the substitution of epoxy resins for the commonly used polystyrene is easy to cast, stable at room temperature, and has the desirable properties of a thermoset or cross-linked system. Such scintillators can be immersed directly in strong solvents, an advantage in many chemical and biological experiments.

  6. Water durability of resin bond to precious metal alloys using adhesive resins containing adhesion promoting monomers.

    Science.gov (United States)

    Kadoma, Yoshinori; Kojima, Katsunori

    2005-12-01

    Adhesive resins for precious metals were prepared by adding an adhesion promoting monomer to MMA-PMMA/TBBO resin. Precious metal alloys bonded by the adhesive resin were thermocycled 0, 1,000, 2,000, or 4,000 times in water between 4 and 60 degrees C, and tensile bond strengths were measured. Debonded metal surfaces after the tensile test were analyzed based on an area of cohesive failure. Three-way ANOVA revealed that all the three parameters--adherend, adhesive monomer, and number of thermal cycles--exhibited a significant influence on bond strength. Bond strength significantly decreased with increasing number of thermal cycles except for resin with 9,10-epithiodecyl 4-vinylbenzoate (EP8VB) to Au alloy. Mean bond strength of adhesive resin with 9,10-epithiodecyl methacrylate (EP8MA), EP8VB, or 3,4-epithiobutyl 2,2-bis(methacryloyloxymethyl)propionate (EP2BMA) exceeded 22 MPa after 4,000 thermal cycles. Analysis of debonded surfaces revealed the applicability of EP8MA, EP8VB, and EP2BMA as an adhesive monomer component of adhesive resin formulations.

  7. Synthesis and characterizations of melamine-based epoxy resins.

    Science.gov (United States)

    Ricciotti, Laura; Roviello, Giuseppina; Tarallo, Oreste; Borbone, Fabio; Ferone, Claudio; Colangelo, Francesco; Catauro, Michelina; Cioffi, Raffaele

    2013-09-05

    A new, easy and cost-effective synthetic procedure for the preparation of thermosetting melamine-based epoxy resins is reported. By this innovative synthetic method, different kinds of resins can be obtained just by mixing the reagents in the presence of a catalyst without solvent and with mild curing conditions. Two types of resins were synthesized using melamine and a glycidyl derivative (resins I) or by adding a silane derivative (resin II). The resins were characterized by means of chemical-physical and thermal techniques. Experimental results show that all the prepared resins have a good thermal stability, but differ for their mechanical properties: resin I exhibits remarkable stiffness with a storage modulus value up to 830 MPa at room temperature, while lower storage moduli were found for resin II, indicating that the presence of silane groups could enhance the flexibility of these materials. The resins show a pot life higher than 30 min, which makes these resins good candidates for practical applications. The functionalization with silane terminations can be exploited in the formulation of hybrid organic-inorganic composite materials.

  8. Comparison of Mechanical Properties of Resin Composites with Resin Modified Glass Ionomers

    Directory of Open Access Journals (Sweden)

    Taha NA

    2015-06-01

    Full Text Available Statement of Problem: There are controversial reports regarding physical and mechanical properties of resin composites and glass ionomer cements. Some revealed higher strength and hardness for resin composites while others showed a comparable value for glass ionomer cements. Evaluation of mechanical properties of different types of resin composites in comparison with resin modified glass ionomers is not widely studied. Objectives: To measure and compare the flexural strength and Vickers hardness of three resin composites and two resins modified glass ionomer cements before and after ageing. Materials and Methods: Three resin composites, i.e. Filtek Supreme XTE (3M ESPE, Ice (SDI, Gradia (GC, and two resins modified glass ionomers, i.e. Fuji II LC (GC and Riva Light Cure (SDI, were selected. Ten barshaped specimens were prepared for each material and cured using LED curing light. After 24 hours storage in distilled water at 37oC, the specimens were randomly divided into two equal groups (n=5. The first group was tested as a baseline and the second group was restored at 37oC for another 29 days. Flexural strength was performed by four-point bending test using universal testing machine at crosshead speed of 0.5mm/min, and the maximum load at failure was recorded. The specimen’s halves were used for evaluating Vickers hardness, using a Digital Hardness Tester (300 g/15 sec and the Vickers hardness number (VHN was recorded. Data were analyzed using one-way analysis of variance (ANOVA, Tukey’s and student’s t-test. Results: After 24 hours of immersion, the highest hardness number was found for Filtek Supreme and Ice and the highest flexural strength was obtained for Gradia. After 30 days of storage, hardness of Fuji II LC and Gradia showed a significant decrease; flexural strength of Ice and Fuji II LC revealed a significant increase while Gradia and Filtek Supreme showed a significant decrease. Conclusions: Resin modified glass ionomers showed

  9. Nanomechanical properties of dental resin-composites.

    Science.gov (United States)

    El-Safty, S; Akhtar, R; Silikas, N; Watts, D C

    2012-12-01

    To determine by nanoindentation the hardness and elastic modulus of resin-composites, including a series with systematically varied filler loading, plus other representative materials that fall into the categories of flowable, bulk-fill and conventional nano-hybrid types. Ten dental resin-composites: three flowable, three bulk-fill and four conventional were investigated using nanoindentation. Disc specimens (15mm×2mm) were prepared from each material using a metallic mold. Specimens were irradiated in the mold at top and bottom surfaces in multiple overlapping points (40s each) with light curing unit at 650mW/cm(2). Specimens were then mounted in 3cm diameter phenolic ring forms and embedded in a self-curing polystyrene resin. After grinding and polishing, specimens were stored in distilled water at 37°C for 7 days. Specimens were investigated using an Agilent Technologies XP nanoindenter equipped with a Berkovich diamond tip (100nm radius). Each specimen was loaded at one loading rate and three different unloading rates (at room temperature) with thirty indentations, per unloading rate. The maximum load applied by the nanoindenter to examine the specimens was 10mN. Dependent on the type of the resin-composite material, the mean values ranged from 0.73GPa to 1.60GPa for nanohardness and from 14.44GPa to 24.07GPa for elastic modulus. There was a significant positive non-linear correlation between elastic modulus and nanohardness (r(2)=0.88). Nonlinear regression revealed a significant positive correlation (r(2)=0.62) between elastic moduli and filler loading and a non-significant correlation (r(2)=0.50) between nanohardness and filler loading of the studied materials. Varying the unloading rates showed no consistent effect on the elastic modulus and nanohardness of the studied materials. For a specific resin matrix, both elastic moduli and nanohardness correlated positively with filler loading. For the resin-composites investigated, the group-average elastic

  10. Petroleum Resins: Separation, Character, and Role in Petroleum

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Speight, James

    2001-01-01

    In petroleum science, the term resin generally implies material that has been eluted from various solid adsorbents, whereas the term maltenes (or petrolenes) indicates a mixture of the resins and oils obtained as filtrates from the asphaltene precipitation. Thus, after the asphaltenes are precipi......In petroleum science, the term resin generally implies material that has been eluted from various solid adsorbents, whereas the term maltenes (or petrolenes) indicates a mixture of the resins and oils obtained as filtrates from the asphaltene precipitation. Thus, after the asphaltenes...... are precipitated, adsorbents are added to the n-pentane solutions of the resins and oils, by which process the resins are adsorbed and subsequently recovered by the use of a more polar solvent, and the oils remain in solution. The resin fraction plays an important role in the stability of petroleum and prevents...... of the fact that the resin fraction is extremely important to the stability of petroleum, there is surprisingly little work reported on the characteristics of the resins. This article summarizes the work that has been carried out in determining the character and properties of the resin constituents...

  11. Contact allergy to epoxy resin: risk occupations and consequences.

    Science.gov (United States)

    Bangsgaard, Nannie; Thyssen, Jacob Pontoppidan; Menné, Torkil; Andersen, Klaus Ejner; Mortz, Charlotte G; Paulsen, Evy; Sommerlund, Mette; Veien, Niels Kren; Laurberg, Grete; Kaaber, Knud; Thormann, Jens; Andersen, Bo Lasthein; Danielsen, Anne; Avnstorp, Christian; Kristensen, Berit; Kristensen, Ove; Vissing, Susanne; Nielsen, Niels Henrik; Johansen, Jeanne Duus

    2012-08-01

    Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown. To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work-related consequences. The dataset comprised 20 808 consecutive dermatitis patients patch tested during 2005-2009. All patients with an epoxy resin-positive patch test were sent a questionnaire. A positive patch test reaction to epoxy resin was found in 275 patients (1.3%), with a higher proportion in men (1.9%) than in women (1.0%). The prevalence of sensitization to epoxy resin remained stable over the study period. Of the patients with an epoxy resin-positive patch test, 71% returned a questionnaire; 95 patients had worked with epoxy resin in the occupational setting, and, of these, one-third did not use protective gloves and only 50.5% (48) had participated in an educational programme. The 1% prevalence of epoxy resin contact allergy is equivalent to reports from other countries. The high occurrence of epoxy resin exposure at work, and the limited use of protective measures, indicate that reinforcement of the law is required. © 2012 John Wiley & Sons A/S.

  12. Mechanistic understanding of fouling of protein A chromatography resin.

    Science.gov (United States)

    Pathak, Mili; Rathore, Anurag S

    2016-08-12

    This paper aims to provide a thorough understanding of how fouling of Protein A resin takes place. Binding and mass transport properties of widely used agarose-based Protein A resin, MabSelect SuRe™, have been examined to understand the mechanism of resin fouling. There could be various factors that impact resin fouling. These include product/impurity build-up due to components in the feed material and ligand degradation due to the use of harsh buffers. To unravel their contributions, cycling studies were performed with and without product loading. The results presented in this paper provide a lucid understanding of the causative factors that limit Protein A chromatographic resin lifetime. The capacity fall for protein A resin at the end of 100th cycle due to use of feed material was found to be five times greater than that without using feed material. Compared to the fresh resin, the cycled resin samples shows 24% reduction in particle porosity and 51% reduction in pore mass transfer coefficient. Transmission electron microscopy (TEM) was used to qualitatively monitor accumulation of foulants on the cycled resin. Fouled resin sample contained a dense residue in the interior and exterior of resin particle both as a film at the bead surface and as granules. The surface activation energy increased five times in the case of fouled resin sample. The major event in fouling was identified as the non-specific adsorption of the feed material components on resin, signaling that pore diffusion is the rate limiting step. It is anticipated that these findings will assist in development of a more robust and economical downstream manufacturing process for monoclonal antibody purification. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Epoxy resins used to seal brachytherapy seed

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Natalia Carolina Camargos; Ferraz, Wilmar Barbosa; Reis, Sergio Carneiro dos; Santos, Ana Maria Matildes dos, E-mail: nccf@cdtn.br, E-mail: ferrazw@cdtn.br, E-mail: reissc@cdtn.br, E-mail: amms@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, BH (Brazil)

    2013-07-01

    Prostate cancer treatment with brachytherapy is recommended for patients with cancer at an early stage. In this treatment, small radioactive seeds are implanted directly in the prostate gland. These seeds are composed at least of one radionuclide carrier and an X-ray marker enclosed within a metallic tube usually sealed by laser process. This process is expensive and, furthermore, it can provoke a partial volatilization of the radionuclide and change the isotropy in dose distribution around the seed. In this paper, we present a new sealing process using epoxy resin. Three kinds of resins were utilized and characterized by scanning electron microscopy (SEM), energy dispersive X ray (EDS) and by differential scanning calorimetry (DSC) after immersion in simulated body fluid (SBF) and in sodium iodine solution (NaI). The sealing process showed excellent potential to replace the sealing laser usually employed. (author)

  14. Flammability of Epoxy Resins Containing Phosphorus

    Science.gov (United States)

    Hergenrother, P. M.; Thompson, C. M.; Smith, J. G.; Connell, J. W.; Hinkley, J. A.

    2005-01-01

    As part of a program to develop fire-resistant exterior composite structures for future subsonic commercial and general aviation aircraft, flame-retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured neat epoxy formulations were characterized by thermogravimetric analysis, propane torch test, elemental analysis, microscale combustion calorimetry, and fire calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness and compressive strength of several cured formulations showed no detrimental effect due to phosphorus content. The chemistry and properties of these new epoxy formulations are discussed.

  15. Epoxy resins in the construction industry.

    Science.gov (United States)

    Spee, Ton; Van Duivenbooden, Cor; Terwoert, Jeroen

    2006-09-01

    Epoxy resins are used as coatings, adhesives, and in wood and concrete repair. However, epoxy resins can be highly irritating to the skin and are strong sensitizers. Some hardeners are carcinogenic. Based on the results of earlier Dutch studies, an international project on "best practices,"--Epoxy Code--with epoxy products was started. Partners were from Denmark, Germany, the Netherlands, and the UK. The "Code" deals with substitution, safe working procedures, safer tools, and skin protection. The feasibility of an internationally agreed "ranking system" for the health risks of epoxy products was studied. Such a ranking system should inform the user of the harmfulness of different epoxies and stimulate research on less harmful products by product developers.

  16. Resin gathering in neotropical resin bugs (Insecta: Hemiptera: Reduviidae): functional and comparative morphology.

    Science.gov (United States)

    Forero, Dimitri; Choe, Dong-Hwan; Weirauch, Christiane

    2011-02-01

    Apiomerini (Reduviidae: Harpactorinae) collect plant resins with their forelegs and use these sticky substances for prey capture or maternal care. These behaviors have not been described in detail and morphological structures involved in resin gathering, transfer, and storage remain virtually undocumented. We here describe these behaviors in Apiomerus flaviventris and document the involved structures. To place them in a comparative context, we describe and document leg and abdominal structures in 14 additional species of Apiomerini that represent all but one of the 12 recent genera in the tribe. Based on these morphological data in combination with the behavioral observations on A. flaviventris, we infer behavioral and functional hypotheses for the remaining genera within the tribe Apiomerini. Setal abdominal patches for resin storage are associated with maternal care so far only documented for species of Apiomerus. Based on the occurrence of these patches in several other genera, we propose that maternal care is widespread within the tribe. Ventral abdominal glands are widespread within female Apiomerini. We propose that their products may prevent hardening of stored resins thus providing long-term supply for egg coating. Judging from the diverse setal types and arrangements on the front legs, we predict six different behavioral patterns of resin gathering within the tribe. Copyright © 2010 Wiley-Liss, Inc.

  17. Acetylene-Terminated Aspartimides And Derived Resins

    Science.gov (United States)

    Hergenrother, Paul M.; Connell, John W.; Havens, Stephen J.

    1989-01-01

    New polymers and derived blends exhibit improved processability and properties. New toughened epoxies exhibit excellent properties, but use temperatures limited. Bismaleimide resins are some base materials formulated to develop materials having moderate use temperatures. Work conducted on use of acetylenic (ethynyl) group to cross-link and extend chains of oligomers and polymers to obtain materials to perform at higher temperatures. Extended to include acetylene-terminated aspartimides (ATA's).

  18. Four Pentasaccharide Resin Glycosides from Argyreia acuta

    Directory of Open Access Journals (Sweden)

    Bang-Wei Yu

    2017-03-01

    Full Text Available Four pentasaccharide resin glycosides, acutacoside F–I (1–4, were isolated from the aerial parts of Argyreia acuta. These compounds were characterized as a group of macrolactones of operculinic acid A, and their lactonization site of 11S-hydroxyhexadecanoic acid was esterified at the second saccharide moiety (Rhamnose at C-2. The absolute configuration of the aglycone was S. Their structures were elucidated by established spectroscopic and chemical methods.

  19. Impact Fracture Study of Filled Epoxy Resins

    OpenAIRE

    Pedro V. Vasconcelos; F. Jorge Lino; António Magalhães; Rui J. Neto

    2004-01-01

    Epoxy-based composites moulds are frequently used for wax and polymer materials injection.Tri-phase materials, composed by an epoxy resin, aluminium particles and milled glass orcarbon fibres were produced with better mechanical and thermal performances than the single materials,increasing the competitiveness of the epoxy rapid tooling processes. Charpy Impact testswere employed to obtain a qualitative indication of the composites toughness. The electronic instrumentationof these tests allows...

  20. Ethynyl-Containing Aromatic Polyamide Resin.

    Science.gov (United States)

    1988-06-21

    laminates and laminating processes for use 0 I in a wide variety of industrial applications has increased 20considerably in the past few years. Glass fiber...the curing step which occurs after the lami- resin represented by either of the folowing formulas: nate sheets are impregnated. The curing process ...2.12; Cl, 23.21; acetamide, NN-dimethylformamide, tetramethyl urea, MW, 266 (mass spectrum). sulfolane , and the like. 45 The polycondemation reaction

  1. Four Pentasaccharide Resin Glycosides from Argyreia acuta.

    Science.gov (United States)

    Yu, Bang-Wei; Sun, Jing-Jing; Pan, Jie-Tao; Wu, Xiu-Hong; Yin, Yong-Qin; Yan, You-Shao; Hu, Jia-Yan

    2017-03-11

    Four pentasaccharide resin glycosides, acutacoside F-I ( 1 - 4 ), were isolated from the aerial parts of Argyreia acuta . These compounds were characterized as a group of macrolactones of operculinic acid A, and their lactonization site of 11 S -hydroxyhexadecanoic acid was esterified at the second saccharide moiety (Rhamnose) at C-2. The absolute configuration of the aglycone was S . Their structures were elucidated by established spectroscopic and chemical methods.

  2. Dental resins properties studied by Bragg gratings

    Science.gov (United States)

    Kalinowski, Hypolito José; Gebert de Oliveira Franco, Ana Paula; Karam, Leandro Zen

    2017-08-01

    Fibre Bragg sensors are a key device in biomedical research for simultaneous measurement of deformations and temperature. The present study shows results from the characterization of dental resin materials with different composition and applications. The results show that all investigated polymer materials demonstrate a temperature rise within the first few seconds after starting activation procedure. The mode of activation and the material composition influence the polymerization shrinkage values.

  3. Ion Exchange Resins Transforming Drug Delivery Systems.

    Science.gov (United States)

    Gupta, Shweta; Benien, Parul; Sahoo, P K

    2010-07-01

    Ion-exchange resins are light, porous, three-dimensional high molecular weight cross - linked matrix of hydrocarbon chains carrying positively or negatively charged sites that can attract an ion of opposite charge from the surrounding medium. There is stoichiometric exchange of mobile ions between the solid and the solution called as Ion-exchange which does not lead to any radical change in the properties and structure of the solid. Depending upon the type of Ionexchanged it can be either Cation-exchange or Anion-exchange. They are prepared in the form of granules, beads or sheets. As drug delivery systems they have received considerable attention after the 1950s due to their inertness, freedom from side effects, high drug loading capacity, ease of sterilization and the fact that their structure can be easily altered to achieve the desired drug release characteristics. Their use is revolutionizing all traditional delivery systems namely - oral, nasal, ophthalmic and parenteral. Ion- exchange resins have been used for the development of novel drug delivery systems (NDDSs), to modify the characteristics of the dosage form and various other biomedical applications. The present article deals with the varied applications of ion-exchange resins for taste making, as resinates (simple and microencapsulated or coated), Pennkinetic systems, in selective recovery of pharmaceuticals, in pH and ionic strength responsive systems, in gastro-retentive systems, in hollow fiber systems, as sigmoidal release systems, as site specific delivery systems and as inotophoretically assisted transdermal drug delivery systems. They also have an immense importance when used as disintegrants / superdisintegrants in formulation of orodispersible tablets, powder processing aids and in the dissolution and stabilization of drugs.

  4. Cross-reactivity among epoxy acrylates and bisphenol F epoxy resins in patients with bisphenol A epoxy resin sensitivity.

    Science.gov (United States)

    Lee, Han N; Pokorny, Christopher D; Law, Sandra; Pratt, Melanie; Sasseville, Denis; Storrs, Frances J

    2002-09-01

    The study's objective was 2-fold: first, to evaluate the potential cross-reactivity between Bis-A epoxy resins and epoxy acrylates and second, to study the cross reactivity between Bis-A epoxy resins and newer Bis-F epoxy resins in patients with allergic contact dermatitis to epoxy resins and had positive patch test to the standard epoxy resin based on bisphenol A. Forty-one patients were patch tested to 23 chemicals including epoxy acrylates, Bis-A epoxy resins, and Bis-F epoxy resins, as well as reactive diluents and nonbisphenol epoxy resins. Questions concerning exposure to epoxy resins, occupational history, and problems with dental work were completed. All patients included in the study had positive reactions to the standard Bis-A epoxy resin. Twenty percent (8 of 41) of the patients reacted to at least one of the epoxy acrylates; the most common reaction was to Bis-GMA. Five of 8 patients who reacted to the epoxy acrylates had dental work, but only one patient had problems from her dental work. Six of 8 patients (75%) who reacted to epoxy resins and epoxy acrylates did not react to aliphatic acrylates. Thirty-two percent (13 of 41) reacted to tosylamide epoxy resin, and none reacted to triglycidyl isocyanurate resin. In addition, all patients (100%) had positive reactions to at least one of the Bis-F epoxy resins that were tested. Most patients with sensitivity to Bis-A epoxy resins do not cross-react with epoxy acrylates. Patients with positive patch test reactions to epoxy acrylates used in dentistry usually do not have symptoms from their dental work. To our knowledge, this is the largest series of patients with sensitivity to the standard Bis-A epoxy resin that have been patch tested with the more recently introduced Bis-F epoxy resins. There is significant cross-reactivity between Bis-A and Bis-F epoxy resins, which can be explained by their structural similarity. Copyright 2002, Elsevier Science (USA). All rights reserved.

  5. Chemoviscosity modeling for thermosetting resins - I

    Science.gov (United States)

    Hou, T. H.

    1984-01-01

    A new analytical model for chemoviscosity variation during cure of thermosetting resins was developed. This model is derived by modifying the widely used WLF (Williams-Landel-Ferry) Theory in polymer rheology. Major assumptions involved are that the rate of reaction is diffusion controlled and is linearly inversely proportional to the viscosity of the medium over the entire cure cycle. The resultant first order nonlinear differential equation is solved numerically, and the model predictions compare favorably with experimental data of EPON 828/Agent U obtained on a Rheometrics System 4 Rheometer. The model describes chemoviscosity up to a range of six orders of magnitude under isothermal curing conditions. The extremely non-linear chemoviscosity profile for a dynamic heating cure cycle is predicted as well. The model is also shown to predict changes of glass transition temperature for the thermosetting resin during cure. The physical significance of this prediction is unclear at the present time, however, and further research is required. From the chemoviscosity simulation point of view, the technique of establishing an analytical model as described here is easily applied to any thermosetting resin. The model thus obtained is used in real-time process controls for fabricating composite materials.

  6. Composite fabrication via resin transfer molding technology

    Energy Technology Data Exchange (ETDEWEB)

    Jamison, G.M.; Domeier, L.A.

    1996-04-01

    The IMPReS (Integrated Modeling and Processing of Resin-based Structures) Program was funded in FY95 to consolidate, evaluate and enhance Sandia`s capabilities in the design and fabrication of composite structures. A key driver of this and related programs was the need for more agile product development processes and for model based design and fabrication tools across all of Sandia`s material technologies. A team of polymer, composite and modeling personnel was assembled to benchmark Sandia`s existing expertise in this area relative to industrial and academic programs and to initiate the tasks required to meet Sandia`s future needs. RTM (Resin Transfer Molding) was selected as the focus composite fabrication technology due to its versatility and growing use in industry. Modeling efforts focused on the prediction of composite mechanical properties and failure/damage mechanisms and also on the uncured resin flow processes typical of RTM. Appropriate molds and test composites were fabricated and model validation studies begun. This report summarizes and archives the modeling and fabrication studies carried out under IMPReS and evaluates the status of composite technology within Sandia. It should provide a complete and convenient baseline for future composite technology efforts within Sandia.

  7. Correlations of norbornenyl crosslinked polyimide resin structures with resin thermo-oxidative stability, resin glass transition temperature and composite initial mechanical properties

    Science.gov (United States)

    Alston, William B.

    1988-01-01

    PMR (polymerization of monomeric reactants) methodology was used to prepare 70 different polyimide oligomeric resins and 30 different unidirectional graphite fiber/polyimide composites. Monomeric composition as well as chain length between sites of crosslinks were varied to examine their effects on resin thermo-oxidative stability and glass transition temperature (Tg) of the cured/postcured resins. A linear correlation of decreasing 316 C resin weight loss/surface area versus (1) decreasing aliphatic content, or (2) increasing benzylic/aliphatic content stoichiometry ratio over a wide range of resin compositions was observed. An almost linear correlation of Tg versus molecular distance between the crosslinks was also observed. An attempt was made to correlate Tg with initial composite mechanical properties (flexural strength and interlaminar shear strength). However, the scatter in mechanical strength data prevented obtaining a clear correlation. Instead, only a range of composite mechanical properties was obtained at 25, 288, and 316 C. Perhaps more importantly, what did become apparent during the correlation study was (1) the PMR methodology could be used to prepare composites from resins containing a wide variety of monomer modifications, (2) that these composites almost invariably provided satisfactory initial mechanical properties as long as the resins formulated exhibited satisfactory processing flow, and (3) that PMR resins exhibited predictable rates of 316 C weight loss/surface area based on their benzylic/aliphatic stoichiometery ratio.

  8. Assessment of cross-reactivity of new less sensitizing epoxy resin monomers in epoxy resin-allergic individuals.

    Science.gov (United States)

    Hagvall, Lina; Niklasson, Ida B; Rudbäck, Johanna; O'Boyle, Niamh M; Niklasson, Eva; Luthman, Kristina; Karlberg, Ann-Therese

    2016-09-01

    Measures to prevent occupational exposure to epoxy resins, including education, medical examination, and voluntary agreements between employers and workers, have not been effective enough to protect against skin sensitization. Therefore, alternatives to the major epoxy resin haptens that have been found to be less sensitizing in the local lymph node assay have been developed. To study the cross-reactivity of two newly designed epoxy resin monomers, with decreased skin-sensitizing potency and good technical properties as compared with diglycidyl ether of bisphenol A (DGEBA), in subjects with known contact allergy to epoxy resin of DGEBA type. Eleven individuals with previous positive patch test reactions to epoxy resin of DGEBA participated in the study. The two alternative epoxy resin monomers were synthesized and patch tested in dilution series in parallel with epoxy resin of DGEBA from the baseline series (containing 92% DGEBA). All participants reacted to epoxy resin of DGEBA on retesting. Three participants reacted to monomer 1. No reactions were seen to monomer 2. The alternative monomers studied showed little or no cross-reactivity with epoxy resin of DGEBA. Decreasing the risk of sensitization by using less sensitizing compounds is important, as contact allergy to epoxy resins is common in spite of thorough preventive measures. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Protein a resin lifetime study: Evaluation of protein a resin performance with a model-based approach in continuous capture.

    Science.gov (United States)

    Behere, Ketki; Cha, Bumjoon; Yoon, Seongkyu

    2018-01-22

    A modified shrinking core model (MSCM) has been used to describe the mechanism for the degradation of Protein A resin particles taking place under continuous chromatographic operation. The model is based on the hypothetical shrinkage of the boundary layer of the resin particles, which house the active Protein A ligands within their pores. The caustic during the sanitization phase of chromatography has been determined to cause the Protein A ligand degradation. Protein A resins provided by manufacturers possess unique caustic stability, which has been used in MSCM to appraise the ligand degradation. The kinetic model utilized semiempirical parameters including diffusion constant, rate constant, stoichiometric factor, and reaction order. The parameters were estimated from column breakthrough experiments to simulate continuous Protein A chromatography for three distinct resins. The reaction order has been identified as the key parameter for predicting the degradation kinetics. The recorded reaction orders vary for three different resins with the resin B showing the highest reaction order of 4 and lowest being 1.65 for the resin C. The model can predict the effects of caustic on resin performance and displayed that minimal degradation of the resins A and B occurred, when exposed to 0.1 N and 0.2N NaOH, retaining up to 96% binding capacity after 240 cycles. The adsorption study conducted for the resin B demonstrated the dynamic physical and chemical changes transpiring through the life cycle of the resin, further supported the degradation model. The performance data demonstrate that the resin B exhibits the desirable performance, with higher reaction order indicating slower resin degradation, higher binding capacities, and increased sustenance of this binding capacity for extended duration. The degradation model can be extended to build effective cleaning strategies for continuous downstream processing.

  10. Resin Poliester Tak Jenuh Untuk Imobilisasi Resin Bekas Pengolahan Simulasi Limbah Radioaktif Cair

    Directory of Open Access Journals (Sweden)

    Herlan Martono

    2017-03-01

    Full Text Available Telah dilakukan penelitian tentang imobilisasi resin bekas pengolah limbah trans-uranium denganresin poliester tak jenuh untuk mengetahui kualitas blok polimer-limbah sebagai fungsi kandunganlimbah. Polimerisasi dilakukan dengan mencampurkan resin poliester tak jenuh dengan katalisdengan perbandingan katalis 1% dari jumlah resin poliester tak jenuh yang digunakan, kemudianditambahkan limbah cair transuranium simulasi. blok polimer-limbah yang terjadi diukur densitas,kuat tekan dengan alat Paul Weber, dan laju pelindihan dengan alat soxhlet pada 100 0C dan 1 atmselama 6 jam. Blok polimer dibuat dengan kandungan limbah 10, 20, 30, 40, dan 50 % berat. Hasilpenelitian menunjukkan bahwa semakin besar kandungan limbah maka kuat tekan blok polimerlimbahsemakin kecil, sedangkan laju pelindihannya semakin besar. Berdasarkan kuat tekan dan lajupelindihan, maka hasil terbaik diperoleh untuk blok-polimer dengan kandungan limbah 20 % dan 30%.

  11. Inorganic resins for clinical use of .sup.213Bi generators

    Science.gov (United States)

    DePaoli, David W [Knoxville, TN; Hu, Michael Z [Knoxville, TN; Mirzadeh, Saed [Knoxville, TN; Clavier, John W [Elizabethton, TN

    2011-03-29

    Applicant's invention is a radionuclide generator resin material for radiochemical separation of daughter radionuclides, particularly .sup.213Bi, from a solution of parental radionuclides, the resin material capable of providing clinical quantities of .sup.213Bi of at least 20-mCi, wherein the resin material comprises a silica-based structure having at least one bifunctional ligand covalently attached to the surface of the silica-based structure. The bifunctional ligand comprises a chemical group having desirable surface functionality to enable the covalent attachment of the bifunctional ligand thereon the surface of the structure and the bifunctional ligand further comprises a second chemical group capable of binding and holding the parental radionuclides on the resin material while allowing the daughter radionuclides to elute off the resin material. The bifunctional ligand has a carbon chain with a limited number of carbons to maintain radiation stability of the resin material.

  12. Interacting Blends of Novel Unsaturated Polyester Amide Resin with Styrene

    Directory of Open Access Journals (Sweden)

    Hasmukh S. Patel

    2004-01-01

    Full Text Available Novel unsaturated poly (ester-amide resins (UPEAs were prepared by the reaction between an epoxy resin, namely diglycidyl ether of bisphenol–A (DGEBA and unsaturated aliphatic bisamic acids using a base catalyst. These UPEAs were then blended with a vinyl monomer namely, Styrene (STY. to produce a homogeneous resin syrup. The curing of these UPEAs-STY. resin blends was carried out by using benzoyl peroxide (BPO as a catalyst and was monitored by using a differential scanning calorimeter (DSC. The glass fibre reinforced composites (i.e. laminates of these UPEA-STY. resin blends were fabricated using the DSC data. The chemical, mechanical and electrical properties of the glass fibre composites have also been evaluated. The unreinforced cured samples of the UPEA-STY. resin blends were also analyzed by thermogravimetry (TGA.

  13. Health Problems of Epoxy Resins and Amine-curing Agents

    Science.gov (United States)

    Bourne, L. B.; Milner, F. J. M.; Alberman, K. B.

    1959-01-01

    Epoxy resins were first introduced about 10 years ago. Toxic effects, particularly dermatitis, have been frequently described. An investigation into the possible causes of pathological sequelae following the use of epoxy resin/amine mixtures has been undertaken. The cause of most cases of dermatitis and sensitization appears to be uncombined amine which is present in recent mixtures and persists in hardened resin for long periods. The results of experiments with two of the most commonly used resin/amine mixtures confirm this. Cold-cured resins are more dangerous and remain so even when hardened. A simple theory is suggested for the mechanism of the reaction between epoxy resins, amines, and biological systems. This theory leads logically to the handling precautions outlined. Images PMID:13651551

  14. Cariogenic Bacteria Degrade Dental Resin Composites and Adhesives

    OpenAIRE

    Bourbia, M.; Ma, D; Cvitkovitch, D G; Santerre, J.P.; Finer, Y.

    2013-01-01

    A major reason for dental resin composite restoration replacement is related to secondary caries promoted by acid production from bacteria including Streptococcus mutans (S. mutans). We hypothesized that S. mutans has esterase activities that degrade dental resin composites and adhesives. Standardized specimens of resin composite (Z250), total-etch (Scotchbond Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 or uninoculated culture medium (control)...

  15. Analytical applications of resins containing amide and polyamine functional groups

    Energy Technology Data Exchange (ETDEWEB)

    Orf, Gene Michael [Iowa State Univ., Ames, IA (United States)

    1977-12-01

    A dibutyl amide resin is used for the separation of uranium(VI), thorium(IV), and zirconium(IV) from each other and several other metal ions. Uranium(VI) and thorium(IV) are determined in the presence of large excesses of foreign metal ions and anions. A practical application of the amide resin is studied by determining uranium in low grade uranium ores. The amide resin is also used for the selective concentration of gold(III) from sea water.

  16. Handling sticky resin by stingless bees (Hymenoptera, Apidae)

    OpenAIRE

    Gastauer, Markus; Campos, Lucio A. O.; WITTMANN, Dieter

    2011-01-01

    For their nest defense, stingless bees (Meliponini) collect plant resins which they stick on intruders like ants or cleptobiotic robber bees causing their immobilization. The aim of this article is to identify all parts of stingless bee workers contacting these sticky resins. Of special interest are those body parts with anti-adhesive properties to resin, where it can be removed without residues. For that, extensive behavioral observations during foraging flight, handling and application of t...

  17. Versatile composite resins simplifying the practice of restorative dentistry.

    Science.gov (United States)

    Margeas, Robert

    2014-01-01

    After decades of technical development and refinement, composite resins continue to simplify the practice of restorative dentistry, offering clinicians versatility, predictability, and enhanced physical properties. With a wide range of products available today, composite resins are a reliable, conservative, multi-functional restorative material option. As manufacturers strive to improve such properties as compression strength, flexural strength, elastic modulus, coefficient of thermal expansion, water sorption, and wear resistance, several classification systems of composite resins have been developed.

  18. Chromium Ions Improve Moisure Resistance of Epoxy Resins

    Science.gov (United States)

    St. Clair, A. K.; St. Clair, T. L.; Stoakley, D. M.; Singh, J. J.; Sprinkle, D. R.

    1986-01-01

    Broad spectrum of thermosetting epoxy resins used on commercial and military aircraft, primarily as composite matrices and adhesives. In new technique, chromium-ion containing epoxy with improved resistance to moisture produced where chromium ions believed to prevent absorption of water molecules by coordinating themselves to hydroxyl groups on epoxy chain. Anticipated that improved epoxy formulation useful as composite matrix resin, adhesive, or casting resin for applications on commercial and advanced aircraft. Improvement made without sacrifice in mechanical properties of polymer.

  19. Acetylene-chromene terminated resins as high temperature thermosets

    Science.gov (United States)

    Godschalx, J. P.; Inbasekaran, M. N.; Bartos, B. R.; Scheck, D. M.; Laman, S. A.

    1990-01-01

    A novel phase transfer catalyzed process for the preparation of propargyl ethers has been developed. The propargyl ethers serve as precursors to a new class of thermosetting resins called acetylene-chromene terminated (ACT) resins. Heat treatment of a solution of propargyl ethers with various catalysts, followed by removal of solvent leads to the ACT resins via partial conversion of the propargyl ether groups to chromenes. This process reduces the energy content of the resin systems and reduces the amount of shrinkage found during cure. Due to the presence of the solvent the process is safe and gives rise to low viscosity products suitable for resin transfer molding and filament winding type applications. Due to the high glass transition temperature, high modulus, and low moisture uptake the cured resins display better than 232 C/wet performance. The thermal stability of the ACT resins in air at 204 C is superior to that of conventional bismaleimide resins. The resins also display excellent electrical properties.

  20. Modified ion exchange resins - synthesis and properties. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Doescher, F.; Klein, J.; Pohl, F.; Widdecke, H.

    1982-01-22

    Sulfomethylated resins are prepared by polymer analogous reactions, starting from macroporous poly(styrene-co-divinylbenzene) matrices. Different reaction paths are discussed and used in the synthesis. Sulfomethylation can be achieved by reaction of a chloromethylated resin with dimethyl sulfide and sodium sulfonate or alternatively by oxidation of polymer-bound thiol groups. Both methods give high conversions as shown by IR spectra and titration of the sulfonic acid groups. Poly(1-(4-hydroxysulfomethylphenyl)ethylene) (3) is obtained by reaction of poly(1-(4-hydroxyphenyl)ethylene) (2) resin with formaldehyde/sodium sulfonate. The thermal stability, catalytic activity, and ion exchange equilibria of the sulfomethylated resin are investigated.

  1. The use of resin-based composite in children.

    Science.gov (United States)

    Donly, Kevin J; García-Godoy, Franklin

    2002-01-01

    Resin-based composites are an integral component of contemporary pediatric restorative dentistry. They can be utilized effectively for preventive resin restorations, moderate Class II restorations, Class III restorations, Class IV restorations, Class V restorations and strip crowns. Tooth isolation to prevent contamination is a critical factor, and high-risk children may not be ideal candidates for resin-based composite restorations. Important factors to consider during composite placement are isolation, polymerization shrinkage and extent of restoration. When utilized correctly, resin-based composites can provide excellent restorations in the primary and permanent dentition.

  2. Microhardness of different resin cement shades inside the root canal.

    Science.gov (United States)

    Vignolo, Valeria; Fuentes, Maria-Victoria; Garrido, Miguel-Angel; Rodríguez, Jesús; Ceballos, Laura

    2012-09-01

    To compare microhardness along the root canal post space of two resin cements in different shades and a dual-cure resin core material. Root canals of 21 bovine incisors were prepared for post space. Translucent posts (X∘Post, Dentsply DeTrey) were luted using one the following resin luting agent: Calibra (Dentsply DeTrey) in Translucent, Medium and Opaque shades, RelyX Unicem (3M ESPE) in Translucent, A2 and A3 shades and the dual-cure resin core material Core∘X flow. All materials were applied according to manufacturers' instructions and were all photopolymerized (Bluephase LED unit, Ivoclar Vivadent, 40s). After 24 hours, roots were transversally cut into 9 slices 1 mm thick from the coronal to apical extremes, three corresponding to each root third. Then, VHNs were recorded (100gf, 30 s) on the resin luting materials along the adhesive interface in all sections. Data were analyzed by two-way ANOVA and SNK tests (α=0.05). A significant influence on microhardness of resin luting material in their respective shades (pmicrohardness values and Calibra the lowest, regardless of the shade selected. All resin luting materials tested exhibited a significantly higher microhardness in the cervical third. Microhardness of resin luting agents tested inside the canal is dependent on material brand and resin cement shade seems to be a less relevant factor. Microhardness decreased along the root canal, regardless of the shade selected.

  3. Diversity matters: how bees benefit from different resin sources.

    Science.gov (United States)

    Drescher, Nora; Wallace, Helen M; Katouli, Mohammad; Massaro, Carmelina F; Leonhardt, Sara Diana

    2014-12-01

    Biodiverse environments provide a variety of resources that can be exploited by consumers. While many studies revealed a positive correlation between biodiversity and consumer biomass and richness, only few studies have investigated how resource diversity affects single consumers. To better understand whether a single consumer species benefits from diverse resources, we tested how the protective function of a defensive plant resource (i.e. resin exploited by social bees) varied among different sources and target organisms (predators, parasites and pathogens). To assess synergistic effects, resins from different plant genera were tested separately and in combination. We found that resin diversity is beneficial for bees, with its functional properties depending on the target organisms, type and composition of resin. Different resins showed different effects, and mixtures were more effective than some of the single resins (functional complementarity). We conclude that resins of different plant species target different organisms and act synergistically where combined. Bees that rely on resin for protection benefit more when they have access to diverse resin sources. Loss of biodiversity may in turn destabilize consumer populations due to restricted access to a variety of resources.

  4. The creep behavior of acrylic denture base resins.

    Science.gov (United States)

    Sadiku, E R; Biotidara, F O

    1996-01-01

    The creep behavior of acrylic dental base resins, at room temperature and at different loading conditions, has been examined. The behaviors of these resins are similar to that of "commercial perspex" at room temperature over a period of 1000 seconds. The pseudo-elastic moduli of the blends of PMMA VC show a significant increase compared with PMMA alone. The addition of the PVC powder to the heat-cured acrylic resin increased the time-dependent elastic modulus. This increase in elastic modulus is advantageous in the production of denture based resins of improv mechanical properties.

  5. Color of bulk-fill composite resin restorative materials.

    Science.gov (United States)

    Barutcigil, Çağatay; Barutcigil, Kubilay; Özarslan, Mehmet Mustafa; Dündar, Ayşe; Yilmaz, Burak

    2017-09-28

    To evaluate the color stability of novel bulk-fill composite resins. Color measurements of a nanohybrid composite resin (Z550) and 3 bulk-fill composite resins (BLK, AFX, XTF; n = 45) were performed before polymerization. After polymerization, color measurements were repeated and specimens were immersed in distilled water or red wine, or coffee. Color change [CIEDE2000 (ΔE00 )] was calculated after 24 h, 1 and 3 weeks. Data were analyzed with Kruskal-Wallis, Mann-Whitney U and Wilcoxon tests (α = 0.05). Color changes observed after polymerization were significant for all groups. Color changes observed in distilled water for Z550 and AFX were significant. Color changes after stored in red wine and coffee were significant for all groups. Bulk-fill composite resin color change increased over time for all groups in red wine and coffee (P composite resin and bulk-fill composite resins. AFX had the highest color change in distilled water. The color of tested bulk-fill composite resins significantly changed after immersion in beverages and over time. Color change observed with the nanohybrid composite resin after 1 week was stable. Clinicians should keep in mind that tested composite resins may change color when exposed to water and significantly change color immediately after they are polymerized. In addition, the color change continues over time should the patient is a coffee and/or red wine consumer. © 2017 Wiley Periodicals, Inc.

  6. Analysis of residual stress in the resin of metal-resin adhesion structures by scanning acoustic microscopy.

    Science.gov (United States)

    Ohno, Hiroki; Endo, Kazuhiko; Nagano-Takebe, Futami; Ida, Yusuke; Kakino, Ken; Narita, Toshio

    2013-01-01

    The residual stress caused by polymerization shrinkage and thermal contraction of a heat-curing resin containing 4-META on a metal-resin structure was measured by a scanning acoustic microscope. The tensile residual stress in the resin occurred within 70 µm of the adhesion interface with a flat plate specimen. The maximum tensile stress was about 58 MPa at the interface. On a metal plate specimen with retention holes, ring-like cracks in the resin occurred around the retention holes with the adhesive specimen and many linear cracks occurred in the resin vertical to the longitudinal direction of the metal frame with the non-adhesive specimens. There was tensile residual stress on the resin surface at the center of the retention holes of the adhesion specimen, indicating that the stress in the specimen with surface treatment for adhesion was higher than in that without surface treatment.

  7. Pengaruh partikel filler terhadap modulus elastisitas resin komposit Effect of filler particles on the elastic moduli of resin composites

    OpenAIRE

    Veni Takarini; Nina Djustiana; Renny Febrida

    2012-01-01

    Modulus of elasticity is one of the mechanical properties of composite resins affects the resistance to deformation, the strength of bonding with tooth structure and wear resistance. Modulus of elasticity is determined by the volume fraction of filler particles as the inorganic phase composite resin. This literature study aims to evaluate the size, shape and type of filler particles that affect the modulus of elasticity for composite resin. In a constant volume fraction, the large...

  8. 40 CFR Table 7 to Subpart Wwww of... - Options Allowing Use of the Same Resin Across Different Operations That Use the Same Resin Type

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Options Allowing Use of the Same Resin Across Different Operations That Use the Same Resin Type 7 Table 7 to Subpart WWWW of Part 63 Protection... Part 63—Options Allowing Use of the Same Resin Across Different Operations That Use the Same Resin Type...

  9. 40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.

    Science.gov (United States)

    2010-07-01

    ... *Polyimides *Polypropylene Resins Polystyrene (Crystal) Polystyrene (Crystal) Modified *Polystyrene—Copolymers *Polystyrene—Acrylic Latexes Polystyrene Impact Resins Polystyrene Latex Polystyrene, Expandable Polystyrene, Expanded *Polysulfone Resins Polyvinyl Acetate *Polyvinyl Acetate—PVC Copolymers *Polyvinyl Acetate...

  10. 77 FR 16508 - National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins...

    Science.gov (United States)

    2012-03-21

    ...: Group IV Polymers and Resins; Pesticide Active Ingredient Production; and Polyether Polyols Production... pollutants: National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins...: Group IV Polymers and Resins; Pesticide Active Ingredient Production; and Polyether Polyols Production...

  11. Improved epoxy resin for constructing cryogenic filament-wound pressure vessels

    Science.gov (United States)

    Molho, R.; Soffer, L. M.

    1971-01-01

    Mechanical properties of new resin at cryogenic temperatures are substantially improved over similar composite structures utilizing conventional resins, while properties at ambient temperature are identical to conventional resin composites.

  12. Preparation and Characterizations of Composite Material Based on Carbon Fiber and Two Thermoset Resins

    Directory of Open Access Journals (Sweden)

    Fouda Hany

    2017-01-01

    Full Text Available In the present investigation, we used two types of thermoset resins (epoxy resin and phenol formaldehyde resin with carbon fiber (CF to produce composite materials. CF/epoxy resin composite and CF/phenolformaldhyde resin composite were fabricated and compared between their mechanical properties as compression, tension and flexural. it was found that mechanical properties of CF/epoxy composite higher than mechanical properties of CF/phenolformaldhyde resin composite such as flexural strength of CF/epoxy resin composite increased by 30 % than flexural strength of CF/phenolformaldhyde resin composite, tensile strength of CF/epoxy resin composite increased by 11.4 % than flexural strength of CF/phenolformaldhyde resin and axial compression strength of CF/epoxy resin composite increased by 14.5 % than flexural strength of CF/phenolformaldhyde resin.

  13. Conversion of ion exchange resin to various functional resins and the application in the field of pharmaceutical sciences

    Science.gov (United States)

    Nakayama, Morio

    Ion exchange resins are widely used for separating ions in the solution, desalination, removal of impurities, and etc. Giving a new function to these ion exchange resins enables the application in more various fields. Until now, we carried out the research work about the following 5 project.: (1) Conversion of ion exchange resins into selective adsorbents by using low molecular reagents, which possess capabilities of a selective reaction with target ions, ion exchange reaction with the ion exchange resin and strong physical adsorption to the ion exchange resin. (2) Synthesis of resins for ion exchange high performance liquid chromatography (IEHPLC) and the analysis of biomaterials. (3) Development of insoluble macromolecular Sn(II) complex based on the aminophosphonic acid type ion exchange resin and its application to the 99mTc labeling of proteins. (4) Development of a new 68Ge-68Ga generator using N-methylglucamine type organic polymer as the adsorbent for 68Ge and production of 68Ga for PET. (5) Preparation of an ion-exchangeable polymer bead wrapped with bilayer membrane structures. In this paper, the application of various functional resins prepared based on ion exchange resin in the field of pharmaceutical sciences has been summarized.

  14. Epoxy-resin adhesive and method for bonding using such an epoxy resin adhesive

    NARCIS (Netherlands)

    Bhowmik, S.; Poulis, J.A.; Benedictus, R.

    2008-01-01

    The invention relates to an epoxy resin adhesive comprising a dotation of nano-substances, wherein the nano- substances are selected from the group comprising carbon-fibre nanotubes, carbon nano-fibres, silicate nano powders, and wherein the nano-substances are dispersed in the adhesive with a

  15. Solidifying process and flame retardancy of epoxy resin cured with boron-containing phenolic resin

    Science.gov (United States)

    Deng, Peng; Shi, Yan; Liu, Yuansen; Liu, Yuan; Wang, Qi

    2018-01-01

    For the sake of improving the charring performance and flame retardancy of epoxy resin (EP), boron-containing phenolic resin (BPR) instead of a conventional curing agent, linear phenolic resin (LPR) was employed to cure EP. Of several possible chemical structures for BPR, the existence of benzyl hydroxy groups in BPR chains has been confirmed using 1H nuclear magnetic resonance spectroscopy. The resonance of these groups may reasonably explain the higher curing reactivity of BPR-cured EP than that of LPR-cured EP. Thermogravimetric analysis, observation of the morphologies of the char residues and X-ray photoelectron spectroscopic were performed to characterize the charring process. Due to the presence of B2O3 produced on the char surface from decomposition of phenyl borates and the facile high self-crosslinking reaction of BPR, a more continuous and stronger char barrier was formed for BPR-cured EP compared to that for the LPR-cured EP system. Therefore the former exhibited much better flame retardancy. In addition, BPR-cured EP also displayed better dynamic mechanical properties, than those observed for LPR-cured EP. It is not subject to the significant lowering the glass transition temperature of the polymer which accompanies curing with LPR. This suggests that BPR cured resin may meet the requirement for utilization at high temperature.

  16. Does Adhesive Resin Application Contribute to Resin Bond Durability on Etched and Silanized Feldspathic Ceramic?

    NARCIS (Netherlands)

    Passos, Sheila Pestana; Valandro, Luiz Felipe; Amaral, Regina; Ozcan, Mutlu; Bottino, Marco Antonio; Kimpara, Estevao Tomomitsu

    2008-01-01

    Purpose: To assess the effect of adhesive application and aging on the bond durability of resin cement to etched and silanized feldspathic ceramic. Materials and Methods: Twenty blocks (6.4 x 6.4 x 4.8 mm) of feldspathic ceramic (Vita VM7) were produced. The ceramic surfaces were conditioned with

  17. Effect of various teas on color stability of resin composites.

    Science.gov (United States)

    Dinç Ata, Gül; Gokay, Osman; Müjdeci, Arzu; Kivrak, Tugba Congara; Mokhtari Tavana, Armin

    2017-12-01

    To investigate the effect of various teas on color stability of resin composites. Two methacrylate-based (Arabesk Top, Grandio) and a silorane-based (Filtek Silorane) resin composites were used. 110 cylindrical samples of each resin composite were prepared (2 mm thickness and 8 mm diameter), polished and stored in distilled water (37°C for 24 hours). They were randomly divided into 11 groups (n= 10) and color measurements were taken. Then the samples were immersed in tap water (control), a black tea, a green tea or one of the eight herbal-fruit teas (37°C for 1 week) and subsequently subjected to the final color measurements. The color change of samples (ΔE*) was calculated, data were subjected to two-way ANOVA and Tukey's HSD tests. Teas, resin composites and their interactions were significant (P= 0.000). All the teas and control caused color changes in all three resin composites. Rosehip tea caused the most color changes, while tap water showed the least in all resin composites. Arabesk Top had the most staining potential in all the teas and control, whereas Filtek Silorane was the most stain resistant except Grandio immersed in sage tea. Color stability of all resin composites used were affected from both structure of resin materials and constituents of teas used. All resin composites were susceptible to staining by all teas especially rosehip tea. Arabesk Top composite showed the greatest color susceptibility in all teas and Filtek Silorane the least with one exception. Color of resin composites can be negatively affected from teas consumed. Clinicians should advise patients that drinking different kind of teas could intensify surface staining of resin based restorations.

  18. Maximizing the functional lifetime of Protein A resins.

    Science.gov (United States)

    Zhang, Jennifer; Siva, Sethu; Caple, Ryan; Ghose, Sanchayita; Gronke, Rob

    2017-05-01

    Protein A chromatography is currently the industry gold-standard for monoclonal antibody and Fc-fusion protein purification. The high cost of Protein A, however, makes resin lifetime and resin reuse an important factor for process economics. Typical resin lifetime studies performed in the industry usually examine the effect of resin re-use on binding capacity, yield, and product quality without answering the fundamental question of what is causing the decrease in performance. A two part mechanistic study was conducted in an attempt to decouple the effect of the two possible factors (resin hydrolysis and/or degradation vs. resin fouling) on column performance over lifetime of the most commonly used alkali-stable Protein A resins (MabSelect SuRe and MabSelect SuRe LX). The change in binding capacity as a function of sodium hydroxide concentration (rate of hydrolysis), temperature, and stabilizing additives was examined. Additionally, resin extraction studies and product cycling studies were conducted to determine cleaning effectiveness (resin fouling) of various cleaning strategies. Sodium hydroxide-based cleaning solutions were shown to be more effective at preventing resin fouling. Conversely, cold temperature and the use of stabilizing additives in conjunction with sodium hydroxide were found to be beneficial in minimizing the rate of Protein A ligand hydrolysis. An effective and robust cleaning strategy is presented here to maximize resin lifetime and thereby the number of column cycles for future manufacturing processes. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:708-715, 2017. © 2017 American Institute of Chemical Engineers.

  19. Effect of configuration factor on gap formation in hybrid composite resin, low-shrinkage composite resin and resin-modified glass ionomer.

    Science.gov (United States)

    Boroujeni, Parvin M; Mousavinasab, Sayyed M; Hasanli, Elham

    2015-05-01

    Polymerization shrinkage is one of the important factors in creation of gap between dental structure and composite resin restorations. The aim of this study was to evaluate the effect of configuration factor (C-factor) on gap formation in a hybrid composite resin, a low shrinkage composite resin and a resin modified glass ionomer restorative material. Cylindrical dentin cavities with 5.0 mm diameter and three different depths (1.0, 2.0 and 3.0 mm) were prepared on the occlusal surface of 99 human molars and the cavities assigned into three groups (each of 33). Each group contained three subgroups depend on the different depths and then cavities restored using resin modified glass ionomer (Fuji II LC Improved) and two type composite resins (Filtek P90 and Filtek Z250). Then the restorations were cut into two sections in a mesiodistal direction in the middle of restorations. Gaps were measured on mesial, distal and pulpal floor of the cavities, using a stereomicroscope. Data analyses using Kruskal-Wallist and Mann-Whitney tests. Increasing C-factor from 1.8 to 3.4 had no effect on the gap formation in two type composite resins, but Fuji II LC Improved showed significant effect of increasing C-factor on gap formation. Taken together, when C-factor increased from 1.8 up to 3.4 had no significant effect on gap formation in two tested resin composites. Although, Filtek P90 restorations showed smaller gap formation in cavities walls compared to Filtek Z250 restorations. High C-factor values generated the largest gap formation. Silorane-based composite was more efficient for cavity sealing than methacrylate-based composites and resin modified glass ionomer. © 2014 Wiley Publishing Asia Pty Ltd.

  20. Early hardness of self-adhesive resin cements cured under indirect resin composite restorations.

    Science.gov (United States)

    Giráldez, Isabel; Ceballos, Laura; Garrido, Miguel A; Rodríguez, Jesús

    2011-04-01

    To determine the influence of curing mode on the surface hardness of seven resin cements used to lute indirect composite restorations. Seven commercial dual-curing resin cements were tested: two were total-etch (RelyX ARC [3M ESPE, St. Paul, MN, USA] and Variolink II [Ivoclar Vivadent, Schaan, Liechtenstein]); one was self-etch (Multilink Automix [Ivoclar Vivadent]), and four were self-adhesive (RelyX Unicem [3M ESPE], Maxcem Elite [Kerr Corp., Orange, CA, USA], SmartCem2 [Dentsply, Detrey, GmbH, Konstanz, Germany], and G-Cem [GC CORPORATION, Itabashi-Ku, Tokyo, Japan]). Three specimens (0.5 × 6.5mm) of each material were prepared for each of three experimental groups: Group 1 (cements allowed to self cure); Group 2 (cements light-cured for 40 seconds); and Group 3 (cements light-cured for 80 seconds). All specimens were cured through a 4-mm-thick composite cylinder (Filtek Z250-A3). Surface microhardness numbers were determined at 20 min after preparation. Results were analyzed by two-way analysis of variance and Student-Newman-Keuls tests (pcement tested (pcements studied, and these values increased even further with a doubling of irradiation time. Self-adhesive cements exhibited different behavior according to the curing mode. RelyX Unicem was highly sensitive to light irradiation, showing the lowest mean values in the self-curing mode. After light irradiation for 40 or 80 seconds, Maxcem Elite exhibited the lowest mean hardness values of all the resin cements tested. The microhardness of resin cements is highly dependent on the brand. Dual-curing resin cements should always be light irradiated for longer periods than that recommended by manufacturers. Dual-curing resin cements should always be light-cured for longer irradiation times, as light irradiation for 80 seconds yields the highest microhardness values in comparison with self-curing or light irradiation for 40 seconds. However, some self-adhesive resin cements exhibit low microhardness values when used

  1. Resin catalysts and method of preparation

    Science.gov (United States)

    Smith, L.A. Jr.

    1986-12-16

    Heat stabilized catalyst compositions are prepared from nuclear sulfonic acid, for example, macroporous crosslinked polyvinyl aromatic compounds containing sulfonic acid groups are neutralized with a metal of Al, Fe, Zn, Cu, Ni, ions or mixtures and alkali, alkaline earth metals or ammonium ions by contacting the resin containing the sulfonic acid with aqueous solutions of the metals salts and alkali, alkaline earth metal or ammonium salts. The catalysts have at least 50% of the sulfonic acid groups neutralized with metal ions and the balance of the sulfonic acid groups neutralized with alkali, alkaline earth ions or ammonium ions.

  2. [Clinical biocompatibility of diacrilic resin veneers].

    Science.gov (United States)

    Dima, Raluca

    2012-01-01

    The great variety of modern composite resins developed recently by manufacturers, offered to clinicians multiple choices of restoring esthetic of frontal teeth. The present study was performed over a period of 8 months. The patients were devided in two groups: A consisted of patients that received indirect veneers; and B consisted of patients that received direct veneers. The clinical evaluation showed no major differences between group A and B, concerning the gingival recesion data and also concerning the plaque index. The data obtained from the study made us assess that direct and indirect composite materials have a clinically acceptable result in terms of biocompatibility when used for frontal veneers.

  3. Two pentasaccharide resin glycosides from Argyreia acuta.

    Science.gov (United States)

    Yin, Yong-Qin; Pan, Jie-Tao; Yu, Bang-Wei; Cui, Hong-Hua; Yan, You-Shao; Chen, Yan-Fen

    2016-01-01

    Two new compounds of acutacosides 1 and 2, pentasaccharide resin glycosides were isolated from the aerial parts of Argyreia acuta. The core of the two compounds was operculinic acid A, and they were esterfied at the same position, just one substituent group was linked at C-2 of Rha. The absolute configuration of the aglycone in the two compounds was established by Mosher's method, which was (11S)-hydroxyhexadecanoic acid (jalapinolic acid). Their structures were established by a combination of spectroscopic and chemical methods.

  4. Organic geochemistry of resins from modern Agathis australis and Eocene resins from New Zealand: Diagenetic and taxonomic implications

    Science.gov (United States)

    Lyons, P.C.; Mastalerz, Maria; Orem, W.H.

    2009-01-01

    A maturation series of resins and fossil resins from New Zealand, ranging in age from Modern to Eocene and ranging from uncoalified to high volatile C bituminous coal, were analyzed by elemental, pyrolysis-gas chromatography (Py-GC), Fourier Transform infrared (FTir), and solid-state 13C nuclear magnetic resonance (13C NMR) techniques. For comparison, four resin samples from the Latrobe Valley, Australia, were analyzed. All of the resins and fossil resins of this study show very high H/C atomic ratios, and are characterized by dominant peaks in the 10-60??ppm range of solid-state 13C NMR spectra and prominent bands in the aliphatic stretching region (2800-3000??cm- 1) of FTir spectra, all indicating a highly aliphatic molecular structure. The 13C NMR and FTir data indicate a diterpenoid structure for these resins. There is an abrupt loss of oxygen that occurs at the Lignite A/Subbituminous C stage, which is attributed to a dramatic loss of carboxyl (COOH) from the diterpenoid molecule. This is a new finding in the diagenesis of resins. This important loss in oxygenated functional groups is attributed to a maturation change. Also, there is a progressive loss of exomethylene (CH2) groups with increasing degree of maturation, as shown by both 13C NMR and FTir data. This change has been noted by previous investigators. Exomethylene is absent in the fossil resins from the Eocene high volatile C bituminous coals. This progressive loss is characteristic of Class I resinites. FTir data indicate that the oxygenated functional groups are strong in all the resin samples except the fossil resin from high volatile C bituminous coal. This important change in oxygenated functional groups is attributed to maturation changes. The 13C NMR and FTir data indicate there are minor changes in the Agathis australis resin from the living tree and soil, which suggests that alteration of A. australis resins begins shortly after deposition in the soil for as little as 1000??years. The Morwell

  5. Effect of photoactivation on the reduction of composite resin contamination.

    Science.gov (United States)

    Pauletti, Natalia A; Girotto, Luiza P S; Leite, Françoise H S; Mario, Débora N

    2017-06-01

    Composite resins are predominantly marketed in developing countries in tube form, and the contents of the tube may be used in numerous procedures for different patients. This represents a problem because of the risk of cross-contamination. This study aimed to evaluate contamination in vitro of the internal contents of composite resin tubes in the dental clinics of a higher-education institution, as well as the effect of photoactivation on the level of contamination. Twenty-five tubes containing composite resin were randomly chosen (by lottery). From each tube, two samples of approximately 2 mm of composite resin were removed, and then one sample, but not the other, was photoactivated. These samples were plated on Brain-Heart Infusion (BHI), Sabouraud and MacConkey agars, and the plates were incubated at 37°C for 24-48 h. Colony counting and Gram staining were performed for subsequent microscopic identification of fungi and bacteria. The non-photoactivated composite resin group presented significantly higher microbial contamination in relation to the photoactivated composite resin group. The photoactivation of camphorquinone present in composite resin produces reactive oxygen species, which might promote cell death of contaminant microorganisms. Thus, although the same tube of composite resin may be used for a number of different patients in the dental clinics of developing countries, the photoactivation process potentially reduces the risk of cross-contamination. © 2017 Eur J Oral Sci.

  6. Mercuric iodide semiconductor detectors encapsulated in polymeric resin

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Joao F. Trencher; Santos, Robinson A. dos; Ferraz, Caue de M.; Oliveira, Adriano S.; Velo, Alexandre F.; Mesquita, Carlos H. de; Hamada, Margarida M., E-mail: mmhamada@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Disch, Christian; Fiederle, Michael [Albert-Ludwigs Universität Freiburg - UniFreibrug, Freiburg Materials Research Center - FMF, Freiburg (Germany)

    2015-07-01

    The development of new semiconductor radiation detectors always finds many setback factors, such as: high concentration of impurities in the start materials, poor long term stability, the surface oxidation and other difficulties discussed extensively in the literature, that limit their use. In this work was studied, the application of a coating resin on HgI2 detectors, in order to protect the semiconductor crystal reactions from atmospheric gases and to isolate electrically the surface of the crystals. Four polymeric resins were analyzed: Resin 1: 50% - 100%Heptane, 10% - 25% methylcyclohexane, <1% cyclohexane; Resin 2: 25% - 50% ethanol, 25% - 50% acetone, <2,5% ethylacetate; Resin 3: 50% - 100% methylacetate, 5% - 10% n-butylacetate; Resin 4: 50% - 100% ethyl-2-cyanacrylat. The influence of the polymeric resin type used on the spectroscopic performance of the HgI{sub 2} semiconductor detector is, clearly, demonstrated. The better result was found for the detector encapsulated with Resin 3. An increase of up to 26 times at the stability time was observed for the detectors encapsulated compared to that non-encapsulated detector. (author)

  7. Evaluation of resin adhesion to zirconia ceramic using some organosilanes

    NARCIS (Netherlands)

    Matinlinna, Jukka P.; Heikkinen, Mo; Ozcan, Mutlu; Lassila, Lippo V. J.; Vallittu, Pekka K.

    Objectives. This study evaluated and compared the effect of three trialkoxysilane coupling agents on the bond strength of a Bis-GMA-based unfilled resin and a dimethacrylate-based resin composite luting cement to a zirconia ceramics (Procera(R) AllZircon, Nobel Biocare, Goteborg, Sweden). Methods.

  8. 21 CFR 177.1650 - Polysulfide polymer-polyepoxy resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polysulfide polymer-polyepoxy resins. 177.1650... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1650 Polysulfide polymer-polyepoxy resins. Polysulfide polymer-polyepoxy res- ins may be safely used as the food-contact surface of...

  9. synthesis, characterisat the alkyd resins deriv esis, characterisation ...

    African Journals Online (AJOL)

    userpc

    ABSTRACT. Quantity of castor seed oil (CSO) obtained value, percentage free fatty acid, iodine specific gravity and moisture content. The resin (oil modified ester) using monoglycer with glycerol (alcoholysis) and subsequen phthalic anhydride to form the alkyd resin characterized using FTIR. The antimicrobia paper disc ...

  10. Effect of different catalysts on urea-formaldehyde resin synthesis

    Science.gov (United States)

    Qi-Ning Sun; Chung-Yun Hse; Todd F. Shupe

    2014-01-01

    Four catalysts (H2SO4, HCl, H3PO4, and NaOH/NH4OH) were studied in the preparation of melamine modified urea– formaldehyde (UFM) resins. 13C-nuclear magnetic resonance spectroscopic analysis of the UFM resins at different synthesis stages revealed the...

  11. Depth of Cure of New Flowable Composite Resins

    Science.gov (United States)

    2012-03-30

    years, the use of composite resin restorations has been on the rise and in many geographical markets they have replaced amalgam restorations altogether...Lindberg, 2004). Composite restorations are preferred by most patients due to their esthetic appeal (Korkmaz, 2007). However, composite resin... esthetic restorative materials possessing strong fundamental restorative characteristics. Since the 1980’s when light-cured direct composite restorative

  12. Porcelain veneer post-bonding crack repair by resin infiltration

    NARCIS (Netherlands)

    Gresnigt, Marco; Magne, Michel; Magne, Pascal

    2017-01-01

    Ceramic laminate veneer restorations are indicated in several clinical situations. Indirect restorations are usually chosen if the less-invasive options - bleaching, resin infiltration, or composite resin restorations - are not possible, or when it is too difficult to achieve an esthetically

  13. Evaluation of some anionic exchange resins as potential tablet ...

    African Journals Online (AJOL)

    Purpose: To determine the potential of some anionic exchange resins as tablet disintegrants. Methods: Dowex1® x2, x4 and x8 resins (crosslinked copolymers of styrene and divinylbenzene with quaternary methyl amine functionality) were evaluated as disintegrant for dibasic calcium phosphate dihydrate tablets. The best ...

  14. Antimicrobial activity of Dracaena cinnabari resin from Soqotra ...

    African Journals Online (AJOL)

    Background: Few studies showed that Dracaena cinnabari resin, collected from Soqotra Island, Yemen, has antimicrobial activity. This study is the first to investigate antimicrobial activity of the resin on both antibiotic multi-resistant human pathogens and on poly-microbial culture. Material and Methods: Antimicrobial activity ...

  15. Fiber-reinforced Composite Resin Prosthesis to Restore Missing ...

    African Journals Online (AJOL)

    A fiber-reinforced composite inlay-onlay FPD was used for a single posterior tooth replacement in a patient refusing implant for psychological reasons. The FRC-FPD was made of pre-impregnated E-glass fibers (everStick, StickTeck, Turku, Finland) embedded in a resin matrix (Stick Resin, StickTeck, Turku, Finland).

  16. Guayule resin detection and influence on guayule rubber

    Science.gov (United States)

    Guayule (Parthenium argentatum) is a natural rubber (cis-1,4-polyisoprene) producing crop, native to North America. Guayule also produces organic resins, complex mixtures of terpenes, triglycerides, guayulins, triterpenoids and other components. During natural rubber extraction, guayule resins can b...

  17. Fatigue resistance of CAD/CAM resin composite molar crowns.

    NARCIS (Netherlands)

    Shembish, F.A.; Tong, H.; Kaizer, M.; Janal, M.N.; Thompson, V.P.; Opdam, N.J.M.; Zhang, Y.

    2016-01-01

    OBJECTIVE: To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. METHODS: Fully anatomically shaped monolithic resin composite molar crowns (Lava

  18. Evaluation of Two Olibanum Resins as Rate Controlling Matrix ...

    African Journals Online (AJOL)

    Olibanum is an oleo-gum resin which is economically and culturally valuable product obtained from several species of the genus Boswellia. In this study, the resins extracted from local olibanum: Boswellia papyrifera (Tigray type) and Boswellia rivae (Ogaden type) were evaluated as matrix forming agents in sustained ...

  19. 21 CFR 872.3670 - Resin impression tray material.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3670 Resin impression tray material. (a) Identification. Resin impression tray material is a device intended for use in a two-step dental mold fabricating... fabrication of crowns, bridges, or full dentures. A preliminary plaster or stone model of the patient's teeth...

  20. Comparison of Cashew Nut Shell Liquid (CNS) Resin with Polyester ...

    African Journals Online (AJOL)

    Akorede

    natural resin is the cashew nut shell liquid (CNSL). Cashew nut shell liquid is a very sticky secretion (gum) from cashew nuts which is similar to gum Arabic. It can be used as a substitute for liquid glue for paper in pharmaceutical and cosmetic industries (Mwaikambo and Anseli, 2001). Cashew gum (like polyester resin) is a ...

  1. Infrared spectroscopic monitoring of urea addition to oriented strandboard resins

    Science.gov (United States)

    Chi-Leung So; Thomas L. Eberhardt; Ernest Hsu; Brian K. Via; Chung Y. Hse

    2007-01-01

    One of the variables in phenol formaldehyde adhesive resin formulation is the addition of urea, which allows the resin manufacturer to manipulate both product functionality and cost. Nitrogen content can be used as a measure of the level of urea addition because most of the nitrogen present is derived from urea added at the end of the preparation process. Nitrogen...

  2. Application conditions for ester cured alkaline phenolic resin sand

    Directory of Open Access Journals (Sweden)

    Ren-he Huang

    2016-07-01

    Full Text Available Five organic esters with different curing speeds: propylene carbonate (i.e. high-speed ester A; 1, 4-butyrolactone; glycerol triacetate (i.e. medium-speed ester B; glycerol diacetate; dibasic ester (DBE (i.e. low-speed ester C, were chosen to react with alkaline phenolic resin to analyze the application conditions of ester cured alkaline phenolic resin. The relationships between the curing performances of the resin (including pH value, gel pH value, gel time of resin solution, heat release rate of the curing reaction and tensile strength of the resin sand and the amount of added organic ester and curing temperature were investigated. The results indicated the following: (1 The optimal added amount of organic ester should be 25wt.%-30wt.% of alkaline phenolic resin and it must be above 20wt.%-50 wt.% of the organic ester hydrolysis amount. (2 High-speed ester A (propylene carbonate has a higher curing speed than 1, 4-butyrolactone, and they were both used as high-speed esters. Glycerol diacetate is not a high-speed ester in alkaline phenolic resin although it was used as a high-speed ester in ester cured sodium silicate sand; glycerol diacetate and glycerol triacetate can be used as medium-speed esters in alkaline phenolic resin. (3 High-speed ester A, medium-speed ester B (glycerol triacetate and low-speed ester C (dibasic ester, i.e., DBE should be used below 15 ìC, 35 ìC and 50 ìC, respectively. High-speed ester A or low-speed ester C should not be used alone but mixed with medium-speed ester B to improve the strength of the resin sand. (4 There should be a suitable solid content (generally 45wt.%-65wt.% of resin, alkali content (generally 10wt.%-15wt.% of resin and viscosity of alkaline phenolic resin (generally 50-300 mPa≤s in the preparation of alkaline phenolic resin. Finally, the technique conditions of alkaline phenolic resin preparation and the application principles of organic ester were discussed.

  3. Removal of Uranium by Exchanger Resins from Soil Washing Solution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Soo; Han, G. S.; Kim, G. N.; Koo, D. S.; Jeong, J. W.; Moon, J. K. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Uranyl ions in the acidic waste solution were sorbed on AM-resin resin with a high sorption efficiency, and desorbed from the resin by a batch-type washing with a 60 .deg. C heated 0.5 M Na{sub 2}CO{sub 3} solution. However, the uranium dissolved in the sulfuric acid solution was not sorbed onto the strong anion exchanger resins. Our group has developed a decontamination process with washing and electrokinetic methods for uranium-contaminated (U-contaminated) soil. However, this process generates a large amount of waste solution containing various metal ions. If the uranium selectively removed from the waste solution, a very small amount of the 2nd waste would be generated. Thus, selective sorption of uranium by ion exchange resins was examined in this study.

  4. Attribute based selection of thermoplastic resin for vacuum infusion process

    DEFF Research Database (Denmark)

    Prabhakaran, R.T. Durai; Lystrup, Aage; Løgstrup Andersen, Tom

    2011-01-01

    The composite industry looks toward a new material system (resins) based on thermoplastic polymers for the vacuum infusion process, similar to the infusion process using thermosetting polymers. A large number of thermoplastics are available in the market with a variety of properties suitable...... for different engineering applications, and few of those are available in a not yet polymerised form suitable for resin infusion. The proper selection of a new resin system among these thermoplastic polymers is a concern for manufactures in the current scenario and a special mathematical tool would...... be beneficial. In this paper, the authors introduce a new decision making tool for resin selection based on significant attributes. This article provides a broad overview of suitable thermoplastic material systems for vacuum infusion process available in today’s market. An illustrative example—resin selection...

  5. Preparation of montmorillonite modified phenolic resin for shell process

    Directory of Open Access Journals (Sweden)

    Xiong Jianmin

    2009-05-01

    Full Text Available The development of montmorillonite modified phenolic resin under microwave irradiation heating was investigated. The effect of montmorillonite content and stirring time on the structure and morphology of synthetic resin was analyzed. The optimum processing procedure was found to be 45 min stirring time with 5.4% montmorillonite addition. Further, the platelet spacing increases with stirring time till montmorillonite exfoliated to nanoscales platelet. When montmorillonite is exfoliated, layered structure at nanoscale can be uniformly distributed in the resin. The overall performance of montmorillonite modifi ed phenolic resin is improved remarkably, such as fl ow ability, tensile strength and toughness property of resin coated sand. However, the gelation speed decreased slightly by adding montmorillonite.

  6. Preparation and characterization of antibacterial orthodontic resin containing silver nanoparticles

    Science.gov (United States)

    Lee, Sang Jin; Heo, Min; Lee, Donghyun; Han, Seungheui; Moon, Ji-Hoi; Lim, Ho-Nam; Kwon, Il Keun

    2018-02-01

    In this study, we developed a hybrid dental resin containing silver nanoparticle (AgNPs) to eliminate periodontal disease causing bacteria such as streptococcus mutans (S. mutans) and streptococcus sobrinus (S. sobrinus). The silver nanoparticles enables the resin to prevent oral pathogen growth during orthodontic therapy. First, AgNPs were directly synthesized in dimethylformamide (DMF) solvent with a capping agent. Second, pure orthodontic primer was mixed with the synthesized AgNPs solvent-slurry followed by photocuring. The resultant material was characterized by physicochemical characterization. Finally, an in vitro antimicrobial test was carried out. The results showed that the AgNPs were fully synthesized and clearly embedded in dental resin. In the bacterial test, the dental resin containing AgNPs showed potent antimicrobial activity against two kinds of bacteria. In conclusion, our methodology may allow for the generation of a wide range of dental resin and composite products which inhibit periodontitis causing bacteria.

  7. Chemical signatures of fossilized resins and recent plant exudates.

    Science.gov (United States)

    Lambert, Joseph B; Santiago-Blay, Jorge A; Anderson, Ken B

    2008-01-01

    Amber is one of the few gemstones based on an organic structure. Found over most of the world, it is the fossil form of sticky plant exudates called resins. Investigation of amber by modern analytical techniques provides structural information and insight into the identity of the ancient plants that produced the source resin. Mass spectrometric analysis of materials separated by gas chromatography has identified specific compounds that are the basis of a reliable classification of the different types of amber. NMR spectroscopy of bulk, solid amber provides a complementary classification. NMR spectroscopy also can be used to characterize modern resins as well as other types of plant exudates such as gums, gum resins, and kinos, which strongly resemble resins in appearance but have very different molecular constitutions.

  8. Novel processing of epoxy resin systems

    Energy Technology Data Exchange (ETDEWEB)

    May, C.A. (Arroyo Research, Watsonville, CA (United States)); Breitigam, W.; Bauer, R.S.

    1993-01-01

    The laminates that are used to prepare advanced composite parts generally require curing at high temperature and pressure, and their raw material shelf lives are limited. The epoxy resin systems that the authors describe here offer the potential of extended shelf life while curing at relatively low temperatures with a method the authors call rapid thermoset processing (RTP). A laminate is formed by stacking the prepreg in a pre-determined manner as required by the end product configuration. The prepreg is then bagged by placing it in a sealed envelope of a heat-resistant film, which is subsequently bonded to a metal surface (the tool) with a heat-resistant vacuum bag putty. The bag has an access hole through which vacuum can be applied to the prepreg stack, facilitating removal of air and other volatiles. This assembly is then heated under vacuum and pressure in an autoclave, the resin melts, and any excess air or volatile matter bleeds from the configuration, resulting in the required dense, void-free laminate.

  9. Has resin-based composite replaced amalgam?

    Science.gov (United States)

    Christensen, Gordon J; Child, Paul L

    2010-02-01

    The major health organizations in the world continue to accept amalgam use, but the "amalgam war" of the 1800s is still going on. The end is not in sight. There is little disagreement that amalgam serves well and, although controversial, it appears to have minimal to no health hazards. There is a wide variation in the relative amount of amalgam placed in developed countries, and many dentists in North America do not use it. However, amalgam is still being used at least some of the time by the majority of practitioners in North America, and most of those practitioners also place resin-based composite in Class II locations. The evolution from amalgam to tooth-colored restorations has been a slow and tumultuous journey. The acceptability of resin-based composite in Class II locations continues to be a question for some dentists, while others have concluded that amalgam is "dead." It would be highly desirable if some of dentists using the alleged poisonous properties of amalgam as a "practice building" ploy would find more legitimate methods to increase their practice activity.

  10. Improving performance of dental resins by adding titanium dioxide nanoparticles.

    Science.gov (United States)

    Sun, Jirun; Forster, Aaron M; Johnson, Peter M; Eidelman, Naomi; Quinn, George; Schumacher, Gary; Zhang, Xinran; Wu, Wen-Li

    2011-10-01

    The objective of this study is to improve the performance of dental resins by adding a small amount of titanium dioxide nanoparticles (TiO₂ NPs), which have outstanding mechanical properties and unique photoactivities. Acrylic acid modified TiO₂ NPs (AP25) were prepared and added to a mixture of bis-phenol-A-dimethacrylate and triethylene glycol dimethacrylate (mass ratio 1:1) at seven mass fractions. Disks made of these resins were subjected to FTIR microspectroscopy, nanoindentation, microindentation, and 3-point bending to determine the degree of vinyl conversion (DC) modulus and hardness. The shear bond strengths (SBS) of dentin adhesives containing various amount of AP25 were also examined. The DC increased as a function of mass fraction of AP25 and reached a plateau at 0.1%. The DC of the resin mixture was improved by ≈7% up to 91.7 ± 0.8%. The elastic modulus and hardness of the composites increased initially as more AP25 were added, and decreased after reached the maximum value at approximately 0.06% mass fraction of AP25. The maximum elastic modulus was ≈48% higher than that of the NP-free resin, and the maximum hardness was more than twice higher than that of the NP-free resin. Using these resin composites as dental adhesives, the mean SBS using resins with 0.1% mass fraction of AP25 was ≈30% higher than those using NP-free resin. By adding a small amount of AP25 to the resin, the DC and the mechanical properties of resins were improved dramatically. These findings could lead to better performing dental adhesives. Copyright © 2011 Academy of Dental Materials. All rights reserved.

  11. Metameric effect between dental porcelain and porcelain repairing resin composite.

    Science.gov (United States)

    Kim, Sung-Hee; Lee, Yong-Keun; Lim, Bum-Soon; Rhee, Sang-Hoon; Yang, Hyeong-Cheol

    2007-03-01

    The objectives were to evaluate the metameric color and hue angle (degrees) changes between dental porcelain and porcelain repairing resin composites. Color of three shades (A2, A3, A3.5) of one brand of dental porcelain and three original shades (A2, A3, A3.5) and three combinations (A2-A3, A3-3.5, A2-A3.5) of three brands of porcelain repairing resin composites (ABT, FSP, TCR) were measured relative to the three standard illuminants (D65, A and F2). Specimen was 2mm in thickness, and 1mm of each shade was layered to make combined shades. Color differences (DeltaEab*) between each shade of dental porcelain and repairing resin composites relative to the three illuminants were calculated, and the ratios of color difference (modified metamerism index) by the change of illuminant were calculated. The ratios of hue angle changes were also compared. Differences in modified metamerism index and the ratio of hue angle changes were influenced by the porcelain shade, brand of resin composites and shade of resin composites. In all three brands of resin composites, A3.5 shade showed the smallest values in modified metamerism index regardless of the shade of porcelain. The average ratio of hue angle changes between each porcelain shade and all the shades of each resin composites showed similar trend when illuminant was changed from D65 to F2. Metameric effect between dental porcelain and repairing resin composites varied depending on the shade of porcelain, brand of resin composite and the illuminant. Therefore, shade matching between porcelain and repairing resin composite should be performed carefully. This study confirmed that shades should be matched under the light corresponding to that of use.

  12. Comparison of the amount of fluoride release from nanofilled resin modified glass ionomer, conventional and resin modified glass ionomer cements.

    Science.gov (United States)

    Upadhyay, Sumitha; Rao, Arathi; Shenoy, Ramya

    2013-03-01

    To investigate and compare the amount of fluoride release of conventional, resin modified and nanofilled resin modified glass ionomer cements. Tablets of glass-ionomer cements were immersed in deionized water and incubated at 37°C. After 1, 2, 7, 15 and 30 days, fluoride ion was measured under normal atmospheric conditions by fluoride ion selective electrode. Buffer (TISAB II) was used to decomplex the fluoride ion and to provide a constant background ionic strength and to maintain the pH of water between 5.0 and 5.5 as the fluoride electrode is sensitive to changes in pH. Statistical evaluation was carried out by one way ANOVA (Analysis of Variance) using SPSS 11.0. The significance level was set at pglass-ionomer cement was highest compared to the other two glass-ionomer cements, but the amount drastically reduced over the period. Although the amount of fluoride release was less than both the resin modified and nanofilled resin modified glass-ionomer cement, the release was sustained consistently for 30 days. The cumulative fluoride release of nanofilled resin modified glass ionomer cement was very less compared to the conventional and resin modified glass ionomer cements and Nanofilled resin modified glass ionomer cement released less but steady fluoride as compared to other resin modified glass ionomer cements.

  13. Significant shear bond strength improvements of a resin-modified glass ionomer cement with a resin coating.

    Science.gov (United States)

    Stallings, Michael T; Stoeckel, Daniel C; Rawson, Kenneth G; Welch, Dan B

    2017-01-01

    Previous evidence has suggested that resin-modified glass ionomer cements (RMGICs) may be sensitive to temperature and moisture changes for the first 24 hours after photopolymerization. To test the hypothesis that a resin coating placed over the surface of an RMGIC restoration would decrease the susceptibility to moisture and temperature conditions, 44 RMGIC samples were prepared in inverted-cone recesses drilled in epoxy resin plates. After abrasion of all samples with 800-grit silicon carbide paper to simulate a diamond bur finish on the surface, a coat of highly filled resin was applied to the experimental group (n = 22) and cured according to the manufacturer's instructions. The plates were thermocycled 500 times between 5°C and 55°C and then maintained at 37°C with 95% humidity. The thermocycled samples were bonded to a second epoxy resin plate filled with RMGIC and subjected to shear bond strength testing. The resin-coated group had a significantly greater mean shear bond strength than the control group (P < 0.05). The resin coating also appeared to affect the mode of failure by significantly increasing the number of mixed failures (P < 0.05). The results suggest that a resin coating protects RMGIC from moisture- and temperature-induced damage and increases shear bond strength.

  14. Comparative evaluation of shear bond strength of conventional composite resin and nanocomposite resin to sandblasted primary anterior stainless steel crown.

    Science.gov (United States)

    Khatri, A; Nandlal, B

    2007-01-01

    To evaluate and compare the shear bond strength of conventional composite resin and nanocomposite resin to sandblasted primary anterior stainless steel crown. The study samples consisted of 30 primary anterior stainless steel crowns (Unitek TM, size R4), embedded in resin blocks with crown, in test groups of 15 samples each. Mounting of the crown was done using resin block with one crown each. Sandblasting was done and the bonding agent Prime and Bond NT (Dentsply) was applied on the labial surface of the primary anterior sandblasted crown. The composite resin and nanocomposite resin were placed into the well of Teflon jig and bonded to Stainless Steel Crowns. The cured samples were placed in distilled water and stored in incubator at 37 degrees C for 48 hours. Shear bond strength was measured using universal testing machine (Hounsefield U.K. Model, with a capacity of 50 KN). Independent sample 't' test revealed a nonsignificant (P < 0.385) difference between mean shear bond strength values of conventional and nanocomposite group. The bond strength values revealed that nanocomposite had slightly higher mean shear bond strength (21.04 +/- 0.56) compared to conventional composite (20.78 +/- 0.60). It was found that conventional composite resin and nanocomposite resin had statistically similar mean shear bond strength, with nanocomposite having little more strength compared to conventional composite.

  15. Comparative evaluation of shear bond strength of conventional composite resin and nanocomposite resin to sandblasted primary anterior stainless steel crown

    Directory of Open Access Journals (Sweden)

    Khatri A

    2007-06-01

    Full Text Available To evaluate and compare the shear bond strength of conventional composite resin and nanocomposite resin to sandblasted primary anterior stainless steel crown. The study samples consisted of 30 primary anterior stainless steel crowns (Unitek TM , size R4, embedded in resin blocks with crown, in test groups of 15 samples each. Mounting of the crown was done using resin block with one crown each. Sandblasting was done and the bonding agent Prime and Bond NT (Dentsply was applied on the labial surface of the primary anterior sandblasted crown. The composite resin and nanocomposite resin were placed into the well of Teflon jig and bonded to Stainless Steel Crowns. The cured samples were placed in distilled water and stored in incubator at 37°C for 48 hours. Shear bond strength was measured using universal testing machine (Hounsefield U.K. Model, with a capacity of 50 KN. Independent sample ′t′ test revealed a nonsignificant ( P < 0.385 difference between mean shear bond strength values of conventional and nanocomposite group. The bond strength values revealed that nanocomposite had slightly higher mean shear bond strength (21.04 ± 0.56 compared to conventional composite (20.78 ± 0.60. It was found that conventional composite resin and nanocomposite resin had statistically similar mean shear bond strength, with nanocomposite having little more strength compared to conventional composite.

  16. Iron(III)-chelating resins. X. Iron detoxification of human plasma with iron(III)-chelating resins

    NARCIS (Netherlands)

    Feng, M.; Feng, M.H.; van der Does, L.; Bantjes, A.; Bantjes, A.

    1994-01-01

    Iron detoxification of human blood plasma was studied with resins containing desferrioxamine B (DFO) or 3-hydroxy-2-methyl-4(1H)-pyridinone (HMP) as iron(III)-chelating groups. The behaviour of four resins was investigated: DFO-Sepharose, HMP-Sepharose and crosslinked copolymers of

  17. [Effects of saliva contamination on bond strength of resin-resin interfaces].

    Science.gov (United States)

    Guo, H J; Gao, C Z; Lin, F; Liu, W; Yue, L

    2017-02-18

    To estimate the bond strength between different resin composite interfaces, and to evaluate the effect of saliva contamination and management with the contamination on the bond strength. Two commercial resin composites containing different types of fillers (AP-X: barium-glass; P60: quartz) were tested in this study. The basic composite blocks were made of AP-X. After wet-ground flatted, the experimental groups were divided into three groups according to the surface treatment: (1)Direct bonding group: the bonding surface was rinsed with distilled water for 20 s, then dried with oil-free air for 20 s; (2)Saliva contamination group: the bonding surface was bathed in saliva for 30 min, then distilled water was rinsed for 20 s and dried with oil-free air for 20 s; (3)Saliva contamination and 75% ethanol wiping group: bonding surface bathed in saliva for 30 min, then wipe the surface with 75% ethanol, distilled water rinse for 20 s and dry with oil-free air for 20 s; The control group was made of the basic composite bulks of AP-X directly bonding with composite P60. Cut each resin block into 1 mm×1 mm×14 mm sticks, observing the micro-structures and detecting the micro-tensile strength of the resin composite interfaces. The bonding strength was measured using micro-tensile tester, then calculated and statistically analyzed by one-way ANOVA. Scanning electronic microscope observation revealed that the control group as well as the direct bonding subgroups, two different resin tags were in good contact with each other. The saliva contamination subgroups had lots of gaps or craters, indicating saliva might have been trapped in the composite buildup and wiping the surface with 75% ethanol had no effect. The micro-tensile bond strength of the control group was (84.07±1.57) MPa and significantly higher than all the other 3 experimental subgroups(Psaliva contamination subgroup was significant lower than the direct bonding subgroup(PSaliva contamination reduced the tensile

  18. A randomized controlled three year evaluation of "bulk-filled" posterior resin restorations based on stress decreasing resin technology

    DEFF Research Database (Denmark)

    van Dijken, Jan W V; Pallesen, Ulla

    2014-01-01

    OBJECTIVE: The objective of this randomized controlled prospective clinical trial was to evaluate the efficacy of a flowable resin composite (SDR) bulk fill technique in posterior restorations and to compare it intraindividually with a conventional 2mm resin composite curing technique in a 3-year....... In all cavities a single step self-etch adhesive (Xeno V) was applied. In one of the cavities of each pair, a flowable resin composite (SDR) was placed, in bulk increments up to 4mm as needed to fill the cavity 2mm short of the occlusal cavosurface. The occlusal part was completed with a nano......-hybrid resin composite (Ceram X mono) layer. In the second cavity, the hybrid resin composite was placed in 2mm increments. The restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 3 years. Caries risk and parafunctional habits of the participants were estimated...

  19. Relined fiberglass post: an ex vivo study of the resin cement thickness and dentin-resin interface

    Directory of Open Access Journals (Sweden)

    Niélli Caetano de SOUZA

    Full Text Available Abstract The aim of this study was to evaluate the thickness of resin cements in the root thirds when using conventional fiberglass posts (CP and relined fiberglass posts (RP in weakened roots and to evaluate the morphological characteristics of the dentin-resin interface. Forty human maxillary anterior teeth had the crown sectioned below the cemento-enamel junction. The canals were endodontically treated and weakened with diamond burs. Teeth were divided into four groups (n = 10: Group 1 – CP + RelyX ARC; Group 2 – CP + RelyX U200; Group 3 – RP + RelyX ARC; and Group 4 – RP + RelyX U200. Prior to luting, 0.1% Fluorescein and 0.1% Rhodamine B dyes were added to an adhesive and resin cement, respectively. Slices were obtained from the apical, middle, and cervical thirds of the root. Confocal laser scanning microscopy images were recorded in four areas (buccal, lingual, mesial, distal of each third. In each area, four equidistant measures of the resin cement were made and the mean value was calculated. The interface morphology was observed. The data were submitted to three-way ANOVA and Tukey’s test (α = 0.05. The interaction between fiberglass posts, resin cement, and root thirds was significant (p < 0.0001. The resin cement thicknesses were significantly lower for RP in comparison with CP, except in the apical third. There was no significant difference between the resin cements for RP. There was formation of resin cement tags and adhesive tags along the root for RP. RP favored the formation of thin and uniform resin cement films and resin tags in weakened roots.

  20. Bonding of synthetic resin teeth to microwave or heat activated denture base resin.

    Science.gov (United States)

    Polyzois, G L; Dahl, J E

    1993-09-01

    Bonding between acrylic resin teeth and a denture base material was investigated after microwave and hot water-bath curing. The specimens were tested according to the methods of the International Organisation for Standardisation (ISO 3336-1977 Dentistry-Synthetic Resin Teeth) using a universal testing machine. Superior bonding was found after hot water-bath curing. The generation of more porosities during microwave curing is the most likely explanation for the bond failures in this group. This finding is of clinical importance as the choice of curing method could influence the risk of loosening of acrylic teeth from the denture. No statistically significant difference in the fracture load between the two types of curing was found, which was expected as the load at fracture is not only related to the binding forces but also to factors such as the contact area and the fracture type.

  1. Analytical method to estimate resin cement diffusion into dentin

    Science.gov (United States)

    de Oliveira Ferraz, Larissa Cristina; Ubaldini, Adriana Lemos Mori; de Oliveira, Bruna Medeiros Bertol; Neto, Antonio Medina; Sato, Fracielle; Baesso, Mauro Luciano; Pascotto, Renata Corrêa

    2016-05-01

    This study analyzed the diffusion of two resin luting agents (resin cements) into dentin, with the aim of presenting an analytical method for estimating the thickness of the diffusion zone. Class V cavities were prepared in the buccal and lingual surfaces of molars (n=9). Indirect composite inlays were luted into the cavities with either a self-adhesive or a self-etch resin cement. The teeth were sectioned bucco-lingually and the cement-dentin interface was analyzed by using micro-Raman spectroscopy (MRS) and scanning electron microscopy. Evolution of peak intensities of the Raman bands, collected from the functional groups corresponding to the resin monomer (C-O-C, 1113 cm-1) present in the cements, and the mineral content (P-O, 961 cm-1) in dentin were sigmoid shaped functions. A Boltzmann function (BF) was then fitted to the peaks encountered at 1113 cm-1 to estimate the resin cement diffusion into dentin. The BF identified a resin cement-dentin diffusion zone of 1.8±0.4 μm for the self-adhesive cement and 2.5±0.3 μm for the self-etch cement. This analysis allowed the authors to estimate the diffusion of the resin cements into the dentin. Fitting the MRS data to the BF contributed to and is relevant for future studies of the adhesive interface.

  2. MODELING RESULTS FROM CESIUM ION EXCHANGE PROCESSING WITH SPHERICAL RESINS

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C.; Hang, T.; Aleman, S.

    2011-01-03

    Ion exchange modeling was conducted at the Savannah River National Laboratory to compare the performance of two organic resins in support of Small Column Ion Exchange (SCIX). In-tank ion exchange (IX) columns are being considered for cesium removal at Hanford and the Savannah River Site (SRS). The spherical forms of resorcinol formaldehyde ion exchange resin (sRF) as well as a hypothetical spherical SuperLig{reg_sign} 644 (SL644) are evaluated for decontamination of dissolved saltcake wastes (supernates). Both SuperLig{reg_sign} and resorcinol formaldehyde resin beds can exhibit hydraulic problems in their granular (nonspherical) forms. SRS waste is generally lower in potassium and organic components than Hanford waste. Using VERSE-LC Version 7.8 along with the cesium Freundlich/Langmuir isotherms to simulate the waste decontamination in ion exchange columns, spherical SL644 was found to reduce column cycling by 50% for high-potassium supernates, but sRF performed equally well for the lowest-potassium feeds. Reduced cycling results in reduction of nitric acid (resin elution) and sodium addition (resin regeneration), therefore, significantly reducing life-cycle operational costs. These findings motivate the development of a spherical form of SL644. This work demonstrates the versatility of the ion exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. The value of a resin with increased selectivity for cesium over potassium can be assessed for further development.

  3. Antibacterial activity of resin rich plant extracts

    Directory of Open Access Journals (Sweden)

    Mohd Shuaib

    2013-01-01

    Full Text Available Background: The in vitro antibacterial activity of resin rich methanolic extracts (RRMEs of Commiphora myrrha, Operculina turpethum, and Pinus roxburghii. Materials and Methods: Different concentration were studied by agar-well diffusion method against Gram-positive (Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Enterococcus faecalis and Gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Shigella dysenteriae. Results: Among all the bacterial strains tested, E. faecalis was most sensitive and S. typhi was resistant to C. myrrha and P. roxburghii. The extracts of O. turpethum were active against all tested strains in which B. subtilis and S. aureus were the most sensitive. Conclusion: This suggested that the antibacterial activity of RRMEs of O. turpethum was more than C. myrrha and P. roxburghii. This probably explains the potential of these plants against a number of infections caused by bacterial strains tested.

  4. Novel acrylic resins for dental applications.

    Science.gov (United States)

    Labella, R; Braden, M; Davy, K W

    1992-01-01

    A heat-cured resin based on a copolymer of bis-phenol-A glycidyl methacrylate (bis-GMA) and tetrahydrofurfuryl methacrylate (THFM) was investigated. Workable pastes were made by adding 90/10 w/w bis-GMA/THFM copolymer powder to a 70/30 w/w monomer of the same composition. The organic filler content was 60-64% w/w. Young's modulus, flexural strength, impact strength, hardness, water absorption and desorption, linear thermal expansion, polymerization shrinkage and glass transition temperature were determined. The materials studied showed high elastic modulus, hardness and glass transition temperature. A relatively low linear thermal expansion was obtained but poor impact strength and low flexural strength, indicating brittleness. Acceptable values were obtained for water absorption.

  5. Devices using resin wafers and applications thereof

    Science.gov (United States)

    Lin, YuPo J [Naperville, IL; Henry, Michael P [Batavia, IL; Snyder, Seth W [Lincolnwood, IL; Martin, Edward [Libertyville, IL; Arora, Michelle [Woodridge, IL; de la Garza, Linda [Woodridge, IL

    2009-03-24

    Devices incorporating a thin wafer of electrically and ionically conductive porous material made by the method of introducing a mixture of a thermoplastic binder and one or more of anion exchange moieties or cation exchange moieties or mixtures thereof and/or one or more of a protein capture resin and an electrically conductive material into a mold. The mixture is subjected to temperatures in the range of from about 60.degree. C. to about 170.degree. C. at pressures in the range of from about 0 to about 500 psig for a time in the range of from about 1 to about 240 minutes to form thin wafers. Devices include electrodeionization and separative bioreactors in the production of organic and amino acids, alcohols or esters for regenerating cofactors in enzymes and microbial cells.

  6. Antibacterial activity of resin rich plant extracts

    Science.gov (United States)

    Shuaib, Mohd; Ali, Abuzer; Ali, Mohd; Panda, Bibhu Prasad; Ahmad, Mohd Imtiyaz

    2013-01-01

    Background: The in vitro antibacterial activity of resin rich methanolic extracts (RRMEs) of Commiphora myrrha, Operculina turpethum, and Pinus roxburghii. Materials and Methods: Different concentration were studied by agar-well diffusion method against Gram-positive (Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Enterococcus faecalis) and Gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Shigella dysenteriae). Results: Among all the bacterial strains tested, E. faecalis was most sensitive and S. typhi was resistant to C. myrrha and P. roxburghii. The extracts of O. turpethum were active against all tested strains in which B. subtilis and S. aureus were the most sensitive. Conclusion: This suggested that the antibacterial activity of RRMEs of O. turpethum was more than C. myrrha and P. roxburghii. This probably explains the potential of these plants against a number of infections caused by bacterial strains tested. PMID:24302834

  7. Recyclability of PET from virgin resin

    Directory of Open Access Journals (Sweden)

    Sandro Donnini Mancini

    1999-01-01

    Full Text Available Bottle grade virgin PET (polyethylene terephthalate resin was investigated through five consecutive injection molding steps to simulate recycling cycles. Tests were carried out after each recycling to evaluate degradation, crystallinity (by density and Differential Scanning Calorimetry-DSC measurements, hardness, and tensile and flexural properties. Consecutive recycling resulted in cumulative chain breaks caused by the material's contact with degrading agents such as temperature, oxygen, mechanical stresses, light, and water. In the fifth recycling step, for example, the number of carboxylic end groups, an indicator of the extent of chain-break, tripled in comparison to the initial molecule. The smaller chains that were formed fit more easily among the larger ones, thus increasing the percentage of crystalline phase in the structure. These two changes in the polymer's structure explained the recycled products' final properties, i.e., the injected samples became progressively harder and more fragile in each recycling step.

  8. Integrating Porous Resins In Enzymatic Processes

    DEFF Research Database (Denmark)

    Al-Haque, Naweed

    synthesis of 1-phenylethylamine using Ȧ-transaminse, the asymmetric synthesis of 1-methyl-3-phenylpropylamine using Ȧ-transaminse and enantioselective synthesis of 2-octanol using alcohol dehydrogenase were selected. VI of resin stability and cost also have to be taken into account in the screening......Increasing pressure mandated by different government policies, for developing sustainable chemical processes for the synthesis of optically pure compounds, has resulted in increased considerations of biocatalysis as a viable option by many industries. Biocatalysis, with its exquisite selective...... properties and potential ‘green’ attributes, presents it as a sustainable alternative. Today, the role of biocatalysis is most evident in the pharmaceutical industry and is currently extending towards fine and bulk chemical production as well. The use of hydrolytic enzymes (lipases) is well established...

  9. Differential scanning calorimetry of the effects of temperature and humidity on phenol-formaldehyde resin cure

    Science.gov (United States)

    X.-M. Wang; B. Riedl; A.W. Christiansen; R.L. Geimer

    1994-01-01

    Phenol-formaldehyde (PF) resin is a widely used adhesive in the manufacture of wood composites. However, curing behaviour of the resin under various environmental conditions is not well known. A differential scanning calorimeter was employed to characterize the degree of resin cure in this study. Resin-impregnated glass cloth samples with varied moisture contents (0,31...

  10. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Melamine-formaldehyde resins in molded articles...-formaldehyde resins in molded articles. Melamine-formaldehyde resins may be safely used as the food-contact...: (a) For the purpose of this section, melamine-formaldehyde resins are those produced when 1 mole of...

  11. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea-formaldehyde resins in molded articles. 177...-formaldehyde resins in molded articles. Urea-formaldehyde resins may be safely used as the food-contact surface... conditions: (a) For the purpose of this section, urea-formaldehyde resins are those produced when 1 mole of...

  12. 40 CFR 63.5728 - What standards must I meet for closed molding resin operations?

    Science.gov (United States)

    2010-07-01

    ... molding resin operations? 63.5728 Section 63.5728 Protection of Environment ENVIRONMENTAL PROTECTION... Standards for Closed Molding Resin Operations § 63.5728 What standards must I meet for closed molding resin operations? (a) If a resin application operation meets the definition of closed molding specified in § 63...

  13. Shear bond strength of a self‑etched resin cement to an indirect ...

    African Journals Online (AJOL)

    ... however there were not statistical difference among the tested surface treatment methods. Conclusion: In Shear bond strength of resin, cement was independent of the surface conditioning methods applied on tested indirect resin composite. Key words: Composite resins, dental bonding, resin cements, surface properties ...

  14. Effect of denture cleansers on color stability, surface roughness, and hardness of different denture base resins

    Directory of Open Access Journals (Sweden)

    Anand Porwal

    2017-01-01

    Conclusion: Color changes of all denture base resins were within the clinically accepted range for color difference. Surface roughness change of conventional heat cure resin was not within the clinically accepted range of surface roughness. The choice of denture cleanser for different denture base resins should be based on the chemistry of resin and cleanser, denture cleanser concentration, and duration of immersion.

  15. Smile makeover utilizing direct composite resin veneers.

    Science.gov (United States)

    Koczarski, Michael

    2008-12-01

    Creating a beautiful smile is more than restoring a single tooth back to its proper form. One must take into account the entire aesthetic zone, along with the mechanics of restoring the teeth to proper form and function. To make this effort even more challenging, the clinician is in full control and completely accountable for making the direct composite resin restorations from which the smile is created. Patients usually won't critique the aesthetics of a posterior direct resin, but once we move into the visible smile (along with the fact that most cosmetic procedures are patient desire- and want-driven) we must be able to deliver what the patient expects. Preplanning the case and avoiding the "prep and pray" approach to the smile-design process is the cornerstone of success. Utilizing tools for the creation of the restorations, such as a preoperative wax-up and silicone putty matrix, help the clinician break the procedure down to individual restorations that when created in harmony with the pre-operative design or wax-up, will allow a final "smile design" to emerge with predictability without getting lost in the daunting task of creating the entire smile all at once. Proper use of ideal composite materials adds the final touch on creating realistic results that even the most discerning patients demand. Layering colors, utilizing differing opacities and translucencies within the restorative process, is a must. Having a "recipe" to follow simplifies the process and gives the clinician confidence that the final result will have that realistic look. All in all, the easiest way to handle a challenging case is to break it down into smaller and more manageable increments in order to ensure a predictable outcome.

  16. Resin flow and void formation in an autoclave cure cycle

    Science.gov (United States)

    Lionetto, Francesca; Lucia, Massimo; Dell'Anna, Riccardo; Maffezzoli, Alfonso

    2016-05-01

    A finite element (FE) model able to evaluate both the evolution of resin flow, degree of reaction and void formation during autoclave cure cycles was developed. The model was implemented using a commercial epoxy matrix widely used in aeronautic field. The FE model also included a kinetic and rheological model whose input parameters were experimentally determined by Differential Scanning Calorimetry and rheological analysis. The FE model was able to predict the evolution of degree of reaction with very good agreement with the experimental data. Moreover, the predicted resin losses were lower than 3% of the overall composite resin content.

  17. The kinetics of fossil resin extraction from a flotation concentrate

    Energy Technology Data Exchange (ETDEWEB)

    Li, L.; Yu, Q.; Miller, J.D. [Univ. of Utah, Salt Lake City, UT (United States)

    1995-11-01

    The kinetics of fossil resin extraction from a flotation concentrate by heptane were investigated as a function of process variables using monosize particles. Experimental results provide for a better understanding of the refining process and the basis for subsequent design and construction of a continuous resin refining circuit. Based on the effect of process variables (particle size, stirring speed, and temperature) the resin extraction rate appears to be controlled by surface solvation phenomena. The initial extraction rate was found to be inversely proportional to the initial particle size and a kinetic model is being developed to describe the experimental results.

  18. Moisture diffusion parameter characteristics for epoxy composites and neat resins

    Science.gov (United States)

    Long, E. R., Jr.

    1979-01-01

    The moisture absorption characteristics of two graphite/epoxy composites and their corresponding cured neat resins were studied in high humidity and water immersion environments at elevated temperatures. Moisture absorption parameters, such as equilibrium moisture content and diffusion coefficient derived from data taken on samples exposed to high humidity and water soak environments, were compared. Composite swelling in a water immersion environment was measured. Tensile strengths of cured neat resin were measured as a function of their equilibrium moisture content after exposure to different moisture environments. The effects of intermittent moderate tensile loads on the moisture absorption parameters of composite and cured neat resin samples were determined.

  19. Evaluation of Amorphous Ribbon Reinforced Resin Matrix Composites.

    Science.gov (United States)

    1980-04-30

    prepreg material. The liquid resins evaluated were Shell Epon 828 , PR-286 supplied by 3M Co., and FR-7015 supplied by Fiber Resin Corporation. The FR...evaluated for the two commonly utilized liquid epoxy resins, PR-286 and EPON 828 , and one film adhesive, EA-9649R. A similar assessment for the other...butaryl (Ref. 10) 172 (25) 44.1 (6.4) 0.68 0.94 2605A/P-1700 (Ref. 13) 1180 (171) 77.9 (11.3) 0.06 0.54 2826/ epon 828 (Ref. 14) 669 (97) 51.7 (7.5) 0.12

  20. KEMAMPUAN LEKAT RESIN KOMPOSIT PADA REPARASI RESTORASI PORSELEN YANG FRAKTUR

    Directory of Open Access Journals (Sweden)

    Ali Noerdin

    2015-08-01

    Full Text Available Since ceramic and metal ceramic restorations in crown and bridge have the potential to fracture, repairing porcelain restorations has become a serious cosmetic and clinical problem. Composite resins have been the material of choice for porcelain repair intraorally because of the esthetic appearance and easy manipulation. However for the repair to withstand functional load, the bond between the repair material and remaining restoration must be strong and durable. Bond strength between composite resins and dental porcelain have been reported by several authors. Several studies reported that silane solution can significantly improve the bond strength of composite resin to dental porcelain.

  1. Advanced ion exchange resins for PWR condensate polishing

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, B. [Rohm and Haas Co. (United States); Tsuzuki, S. [Rohm and Haas Co. (Japan)

    2002-07-01

    The severe chemical and mechanical requirements of a pressurized water reactor (PWR) condensate polishing plant (CPP) present a major challenge to the design of ion exchange resins. This paper describes the development and initial operating experience of improved cation and anion exchange resins that were specifically designed to meet PWR CPP needs. Although this paper focuses specifically on the ion exchange resins and their role in plant performance, it is also recognized and acknowledged that excellent mechanical design and operation of the CPP system are equally essential to obtaining good results. (authors)

  2. Application of Ketone-Based Resins as Anticorrosive Coating

    Directory of Open Access Journals (Sweden)

    Esma Sezer

    2011-01-01

    Full Text Available Effect of some newly synthesized modified ketonic resins on corrosion inhibition of stainless steel (SS and copper (Cu was investigated in acidic medium. Carboxyl, hydroxyl, and carbonyl functionalized resins have been coated on metal electrode as a thin film by dipping method. Corrosion characteristics of coating on SS (304 L and Cu were investigated by polarization, open-circuit, and impedance measurement. These measurements performed at different time and the stability of polymeric coating were tested with time in acidic medium. The resin coating was able to protect both the SS and copper.

  3. Microtensile bond strength of indirect resin composite to resin-coated dentin: interaction between diamond bur roughness and coating material.

    Science.gov (United States)

    Kameyama, Atsushi; Oishi, Takumi; Sugawara, Toyotarou; Hirai, Yoshito

    2009-02-01

    This aim of this study was to determine the effect of type of bur and resin-coating material on microtensile bond strength (microTBS) of indirect composite to dentin. Dentin surfaces were first ground with two types of diamond bur and resin-coated using UniFil Bond (UB) or Adper Single Bond (SB), and then bonded to a resin composite disc for indirect restoration with adhesive resin cement. After storage for 24 hr in distilled water at 37 degrees C, microTBS was measured (crosshead speed 1 mm/min). When UB was applied to dentin prepared using the regular-grit diamond bur, microTBS was significantly lower than that in dentin prepared using the superfine-grit bur. In contrast, no significant difference was found between regular-grit and superfine-grit bur with SB. However, more than half of the superfine-grit specimens failed before microTBS testing. These results indicate that selection of bur type is important in improving the bond strength of adhesive resin cement between indirect resin composite and resin-coated dentin.

  4. Physical, mechanical and rheological characterization of resin-based pit and fissure sealants compared to flowable resin composites.

    Science.gov (United States)

    Beun, Sébastien; Bailly, Christian; Devaux, Jacques; Leloup, Gaëtane

    2012-04-01

    The purpose of this study was to compare the mechanical and rheological properties of resin-based pit and fissure sealants to flowable resin composites in order to define clinical indications based on these properties. Eight flowable resin composites (Admira Flow, Filtek Supreme XT Flow, FlowLine, Grandio Flow, Point-4 Flowable, Premise Flowable, Revolution Formula 2, X-Flow) and four resin-based pit and fissure sealants (Clinpro, Delton FS(+), Estiseal F, Guardian Seal) were used in this study. Their filler weight content was measured by thermogravimetric analysis. Mechanical properties were measured: dynamic and static moduli of elasticity, flexural strength and Vickers microhardness. Rheological measurements were performed using a dynamic oscillation rheometer. Flowable resin composites have by far better mechanical properties than pit and fissure sealants, except for Delton FS(+). All the materials tested are non-Newtonian, shear thinning fluids. They all showed elasticity even at the lowest frequencies but elasticity differs pretty much from one material to another. Resin-based pit and fissure sealants seem appropriate for preventive pit and fissure sealing. For enlarged fissures, it can be assumed that flowable resin composites with low elasticity at low frequency are more appropriate. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  5. Shear Bond Strength between Fiber-Reinforced Composite and Veneering Resin Composites with Various Adhesive Resin Systems.

    Science.gov (United States)

    AlJehani, Yousef A; Baskaradoss, Jagan K; Geevarghese, Amrita; AlShehry, Marey A; Vallittu, Pekka K

    2016-07-01

    The aim of this research was to evaluate the shear bond strength of different laboratory resin composites bonded to a fiber-reinforced composite substrate with some intermediate adhesive resins. Mounted test specimens of a bidirectional continuous fiber-reinforced substrate (StickNet) were randomly assigned to three equal groups. Three types of commercially available veneering resin composites - BelleGlass®, Sinfony®, and GC Gradia® were bonded to these specimens using four different adhesive resins. Half the specimens per group were stored for 24 hours; the remaining were stored for 30 days. There were 10 specimens in the test group (n). The shear bond strengths were calculated and expressed in MPa. Data were analyzed statistically, and variations in bond strength within each group were additionally evaluated by calculating the Weibull modulus. Shear bond values of those composites are influenced by the different bonding resins and different indirect composites. There was a significant difference in the shear bond strengths using different types of adhesive resins (p = 0.02) and using different veneering composites (p veneering composite to bidirectional continuous fiber-reinforced substrate is influenced by the brand of the adhesive resin and veneering composite. © 2015 by the American College of Prosthodontists.

  6. Effects of prepolymerized particle size and polymerization kinetics on volumetric shrinkage of dental modeling resins.

    Science.gov (United States)

    Kwon, Tae-Yub; Ha, Jung-Yun; Chun, Ju-Na; Son, Jun Sik; Kim, Kyo-Han

    2014-01-01

    Dental modeling resins have been developed for use in areas where highly precise resin structures are needed. The manufacturers claim that these polymethyl methacrylate/methyl methacrylate (PMMA/MMA) resins show little or no shrinkage after polymerization. This study examined the polymerization shrinkage of five dental modeling resins as well as one temporary PMMA/MMA resin (control). The morphology and the particle size of the prepolymerized PMMA powders were investigated by scanning electron microscopy and laser diffraction particle size analysis, respectively. Linear polymerization shrinkage strains of the resins were monitored for 20 minutes using a custom-made linometer, and the final values (at 20 minutes) were converted into volumetric shrinkages. The final volumetric shrinkage values for the modeling resins were statistically similar (P > 0.05) or significantly larger (P resin and were related to the polymerization kinetics (P resin structures rather than the use of dental modeling resins.

  7. Extraction chromatography of neodymium by an organophosphorous extractant supported on various polymeric resins

    Energy Technology Data Exchange (ETDEWEB)

    Takigawa, D.Y.

    1993-04-01

    Fifteen resins coated with dihexyl-N,N-diethylcarbamoylmethyl phosphonate (CMP) were studied for their extraction of neodymium (Nd) in 4.0 and 7.0 M nitric acid. Resin properties, such as chemical composition and physical morphology, which can influence Nd extraction as well as subsequent resin regeneration (Nd stripping), were identified. Hydrophilic or polar resins coated with CMP efficiently extracted the Nd. Resins initially washed free of residual monomer and solvent before CMP coating outperformed their untreated counterparts. The macroporous styrene-divinylbenzene hydrophobic resins that were high in surface area were less effective supports compared with hydrophilic microporous Aurorez, polybenzimidazole (PBI) and macroporous Amberlite polyacrylic resins. Only one resin, Duolite C-467, showed no measurable improvement in Nd extraction with CMP coating. CMP-coated Aurorez PBI, a microporous and hydrophilic polymeric resin with an average surface area, showed the best overall efficiency for Nd removal and resin regeneration.

  8. Effects of laboratory disinfecting agents on color stability of denture acrylic resins.

    Science.gov (United States)

    McNeme, S J; von Gonten, A S; Woolsey, G D

    1991-07-01

    This study determined the effects of chemical disinfecting agents on denture acrylic resins. Tested resins included the products CH Lucitone, Triad VLC, and Truliner. The disinfecting agents were sodium hypochlorite, Exspor, Cidex, and Wescodyne-D. Acrylic resin samples were placed in the various disinfecting agents and then evaluated for color changes at time intervals ranging from 15 minutes to 72 hours. No observable color change of any acrylic resin was seen before 2 hours. Both 1% sodium hypochlorite and 2% Cidex disinfectants produced the least discoloration of the acrylic resins, and Wescodyne-D disinfectant produced the most acrylic resin discoloration. Truliner resin discolored more than Triad VLC resin, and both underwent more color change than CH Lucitone resin. If manufacturers' recommended disinfecting times are followed, clinical and laboratory disinfection of acrylic resin dentures should cause no observable color change.

  9. Fracture frequency and longevity of fractured resin composite, polyacid-modified resin composite, and resin-modified glass ionomer cement class IV restorations: an up to 14 years of follow-up

    DEFF Research Database (Denmark)

    van Dijken, Jan W V; Pallesen, Ulla

    2010-01-01

    The aim of this study was to evaluate the fracture frequency and longevity of fractured class IV resin composite (RC), polyacid-modified resin composite (compomer; PMRC), and resin-modified glass ionomer cement (RMGIC) restorations in a longitudinal long-term follow-up. Eighty-five class IV RC (43...

  10. Removal of radioactive materials and heavy metals from water using magnetic resin

    Science.gov (United States)

    Kochen, Robert L.; Navratil, James D.

    1997-01-21

    Magnetic polymer resins capable of efficient removal of actinides and heavy metals from contaminated water are disclosed together with methods for making, using, and regenerating them. The resins comprise polyamine-epichlorohydrin resin beads with ferrites attached to the surfaces of the beads. Markedly improved water decontamination is demonstrated using these magnetic polymer resins of the invention in the presence of a magnetic field, as compared with water decontamination methods employing ordinary ion exchange resins or ferrites taken separately.

  11. Preparation and Analytical Properties of 4-Hydroxybenzaldehyde, Biuret and Formaldehyde Terpolymer Resin

    OpenAIRE

    Bunian A. Shareef; Ibrahim F. Waheed; Kariem K. Jalaot

    2014-01-01

    The chelating resin was synthesized by polycondensation reaction of 4-hydroxy benzaldehyde, formaldehyde and biuret under alkaline condition. The prepared resin was characterized by IR spectroscopy and 1HNMR spectroscopy. The resin sample was cured isothermally at 1200C.The DSC scans was measured for the prepared resin. The analytical evaluation of the prepared resin toward the studied ions (Hg2+, Ni2+ and Pb2+) using the batch method. It was employed to study selectivity of metal ion...

  12. Solvent impregnated resins for the recovery of gold from gold(I)thiourea solutions

    OpenAIRE

    Fitzpatrick, Fiona

    1997-01-01

    Solvent Impregnated Resins (SIRs) are high surface area, macroporous, polymeric resins which have been physically impregnated with an organic solvent. In this research, three resins have been impregnated with Di-2- ethylhexyl phosphoric acid, a solvent which has shown selectivity to gold. The ability of the resins to recover gold(I)thiourea perchlorate from solution has been investigated. The resins have been studied both bare and when impregnated with the solvent and their efficiency was...

  13. Metabolomics reveals the origins of antimicrobial plant resins collected by honey bees.

    Science.gov (United States)

    Wilson, Michael B; Spivak, Marla; Hegeman, Adrian D; Rendahl, Aaron; Cohen, Jerry D

    2013-01-01

    The deposition of antimicrobial plant resins in honey bee, Apis mellifera, nests has important physiological benefits. Resin foraging is difficult to approach experimentally because resin composition is highly variable among and between plant families, the environmental and plant-genotypic effects on resins are unknown, and resin foragers are relatively rare and often forage in unobservable tree canopies. Subsequently, little is known about the botanical origins of resins in many regions or the benefits of specific resins to bees. We used metabolomic methods as a type of environmental forensics to track individual resin forager behavior through comparisons of global resin metabolite patterns. The resin from the corbiculae of a single bee was sufficient to identify that resin's botanical source without prior knowledge of resin composition. Bees from our apiary discriminately foraged for resin from eastern cottonwood (Populus deltoides), and balsam poplar (P. balsamifera) among many available, even closely related, resinous plants. Cottonwood and balsam poplar resin composition did not show significant seasonal or regional changes in composition. Metabolomic analysis of resin from 6 North American Populus spp. and 5 hybrids revealed peaks characteristic to taxonomic nodes within Populus, while antimicrobial analysis revealed that resin from different species varied in inhibition of the bee bacterial pathogen, Paenibacillus larvae. We conclude that honey bees make discrete choices among many resinous plant species, even among closely related species. Bees also maintained fidelity to a single source during a foraging trip. Furthermore, the differential inhibition of P. larvae by Populus spp., thought to be preferential for resin collection in temperate regions, suggests that resins from closely related plant species many have different benefits to bees.

  14. Metabolomics reveals the origins of antimicrobial plant resins collected by honey bees.

    Directory of Open Access Journals (Sweden)

    Michael B Wilson

    Full Text Available The deposition of antimicrobial plant resins in honey bee, Apis mellifera, nests has important physiological benefits. Resin foraging is difficult to approach experimentally because resin composition is highly variable among and between plant families, the environmental and plant-genotypic effects on resins are unknown, and resin foragers are relatively rare and often forage in unobservable tree canopies. Subsequently, little is known about the botanical origins of resins in many regions or the benefits of specific resins to bees. We used metabolomic methods as a type of environmental forensics to track individual resin forager behavior through comparisons of global resin metabolite patterns. The resin from the corbiculae of a single bee was sufficient to identify that resin's botanical source without prior knowledge of resin composition. Bees from our apiary discriminately foraged for resin from eastern cottonwood (Populus deltoides, and balsam poplar (P. balsamifera among many available, even closely related, resinous plants. Cottonwood and balsam poplar resin composition did not show significant seasonal or regional changes in composition. Metabolomic analysis of resin from 6 North American Populus spp. and 5 hybrids revealed peaks characteristic to taxonomic nodes within Populus, while antimicrobial analysis revealed that resin from different species varied in inhibition of the bee bacterial pathogen, Paenibacillus larvae. We conclude that honey bees make discrete choices among many resinous plant species, even among closely related species. Bees also maintained fidelity to a single source during a foraging trip. Furthermore, the differential inhibition of P. larvae by Populus spp., thought to be preferential for resin collection in temperate regions, suggests that resins from closely related plant species many have different benefits to bees.

  15. Effects of Prepolymerized Particle Size and Polymerization Kinetics on Volumetric Shrinkage of Dental Modeling Resins

    OpenAIRE

    Kwon, Tae-Yub; Ha, Jung-Yun; Chun, Ju-Na; Son, Jun Sik; Kim, Kyo-Han

    2014-01-01

    Dental modeling resins have been developed for use in areas where highly precise resin structures are needed. The manufacturers claim that these polymethyl methacrylate/methyl methacrylate (PMMA/MMA) resins show little or no shrinkage after polymerization. This study examined the polymerization shrinkage of five dental modeling resins as well as one temporary PMMA/MMA resin (control). The morphology and the particle size of the prepolymerized PMMA powders were investigated by scanning electro...

  16. Comparative evaluation of sorption, solubility and microhardness of heat cure polymethylmethacrylate denture base resin & flexible denture base resin.

    Science.gov (United States)

    Shah, Jay; Bulbule, Nilesh; Kulkarni, Shilpa; Shah, Riddhi; Kakade, Dilip

    2014-08-01

    The aim of the study was to evaluate and compare sorption, solubility and microhardness of heat cure polymethylmethacrylate (PMMA) denture base resin and flexible (thermoplastic polyamide nylon) denture base resin. Sorption, solubility and microhardness were assessed to determine compliance with ADA Specification no. 12. RESULTs were assessed using statistical and observational analyses. All materials satisfied ADA requirements for sorption, solubility and microhardness. Heat cure PMMA showed more sorption, solubility and microhardness than flexible (thermoplastic polyamide nylon). Flexible (thermoplastic polyamide nylon) resin absorbs less water, is less soluble and is more flexible than PMMA.

  17. Interfacial microscopic examination and chemical analysis of resin-dentin interface of self-adhering flowable resin composite.

    Science.gov (United States)

    Hamdy, Tamer M

    2017-01-01

    Background: The newly introduced self-adhering flowable resin-composites decrease the required time for application by incorporation of an acidic adhesive monomer, thus reducing the number of steps, but its bonding is still uncertain. The aim of this study was to evaluate the interfacial microscopic examination and chemical analysis at the resin-dentin interface of a self-adhering flowable resin composite (Vertise™Flow Self-Adhering Flowable Composite, Kerr Dental, USA) versus a total-etch (Te-Econom Plus) resin composite, using an etching agent (Eco-Etch gel) and bonding agent (Single Bond Universal). Methods: Sixteen freshly extracted sound human posterior teeth were used. The teeth were randomly divided into two groups: 8 specimens per type of composite. Standard-shaped class V cavities were prepared on the buccal surface. One group was restored by Te-Econom Plus resin composite by total-etch technique using Eco-Etch gel, which was applied to dentine for 15 seconds, followed by rinsing, drying and bonding agent application (Single Bond Universal). The other group restored directly with self-adhering resin composite (Vertise-Flow) without application of etch or bond. Curing was done for 20 seconds using a light emitting diode light curing unit. Evaluation of the resin-dentin interface was done microscopically by examination of marginal gap distance in μm using scanning electron microscope (SEM), and chemical analysis of silver particles was observed using SEM with energy-dispersive X-ray spectrometry after 24 hours of specimen storage in ammoniacal silver nitrate. Results: Regarding marginal gap distance (µm) and silver atomic % mean values, teeth restored with self-adhering resin composite (Vertise-Flow) showed significantly higher mean values than the multi-step etch and rinse resin composite group (5.2 vs 0; 12.2 vs 8.2, respectively). Conclusions: Resin-dentin bonding using total-etch resin composite technique was more effective than self

  18. Effect of repair resin type and surface treatment on the repair strength of heat-polymerized denture base resin.

    Science.gov (United States)

    Alkurt, Murat; Yeşil Duymuş, Zeynep; Gundogdu, Mustafa

    2014-01-01

    Acrylic resin denture fracture is common in prosthodontic practice. When fractured denture bases are repaired, recurrent fractures frequently occur at the repair surface interface or adjacent areas. The purpose of this study was to evaluate the effect of different surface treatments on the flexural strength of the acrylic resin denture base repaired with heat-polymerized acrylic resin, autopolymerizing resin, and light-polymerized acrylic resin. Ninety-six specimens of heat-polymerized acrylic resin were prepared according to the American Dental Association Specification No. 12 (65.0 × 10.0 × 2.5 mm) and sectioned into halves to create a repair gap (3.0 × 10 × 2.5 mm). The sectioned specimens were divided into 3 groups according to their repair materials. The specimens from each group were divided into 4 subgroups according to their surface treatments: a control group without any surface treatment; an experimental group treated with methyl methacrylate monomer (MMA group); an experimental group treated with airborne-particle abrasion with aluminum oxide particles of 250-μm particle size (abrasion group); and an experimental group treated with erbium:yttrium-aluminum-garnet laser (laser group). After the surface treatments, the 3 materials were placed into the repair gaps and then polymerized. After all of the specimens had been ground and polished, they were stored in distilled water at 37°C for 1 week and subjected to a 3-point bend test. Data were analyzed with a 2-way analysis of variance, and the Tukey honestly significant difference test was performed to identify significant differences (α=.05). The effects of the surface treatments and repair resins on the surface of the denture base resin were examined with scanning electron microscopy. Significant differences were found among the groups in terms of repair resin type (Psurface-treated specimens had higher flexural strength than controls, except the surface treated with the methyl methacrylate in the

  19. Development of amino resin for paint formulation: Copolymerization ...

    African Journals Online (AJOL)

    SERVER

    2007-06-18

    Jun 18, 2007 ... Key words: Methylol urea-triethanolamine copolymer, flexibility, formaldehyde emission, copolymerization, methylol urea, esterification, tensile properties. INTRODUCTION. Amino resins are thermosetting polymers that are largely used in many industrial applications. Urea formaldehyde accounts for over ...

  20. Resin Infusion Rigidized Inflatable Concept Development and Demonstration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Utilizing resin infusion to rigidize an inflatable structure and form fiber-reinforced composites on-orbit is a novel concept that builds on current NASA technology...

  1. (Methacrylic Acid-Co-Divinylbenzene) Resin as Filler

    African Journals Online (AJOL)

    divinylbenzene) resin (PMD) as a new filler-binder for direct compression tablets. Methods: Powder properties of PMD and MCC were characterized. Tablets made from PMD and MCC with and without propranolol hydrochloride were evaluated for ...

  2. (Methacrylic Acid-Co-Divinylbenzene) Resin as Filler- Binder for

    African Journals Online (AJOL)

    divinylbenzene) resin (PMD) as a new filler-binder for direct compression tablets. Methods: Powder properties of PMD and MCC were characterized. Tablets made from PMD and MCC with and without propranolol hydrochloride were evaluated for ...

  3. Quantification and Purification of Mulberry Anthocyanins with Macroporous Resins

    Directory of Open Access Journals (Sweden)

    Xueming Liu

    2004-01-01

    Full Text Available Total anthocyanins in different cultivars of mulberry were measured and a process for the industrial preparation of mulberry anthocyanins as a natural food colorant was studied. In 31 cultivars of mulberry, the total anthocyanins, calculated as cyanidin 3-glucoside, ranged from 147.68 to 2725.46 mg/L juice. Extracting and purifying with macroporous resins was found to be an efficient potential method for the industrial production of mulberry anthocyanins as a food colorant. Of six resins tested, X-5 demonstrated the best adsorbent capability for mulberry anthocyanins (91 mg/mL resin. The adsorption capacity of resins increased with the surface area and the pore radius. Residual mulberry fruit juice after extraction of pigment retained most of its nutrients, except for anthocyanins, and may provide a substrate for further processing.

  4. Analysis of polymerization time on abrasive wear of dental resins

    Directory of Open Access Journals (Sweden)

    Eduardo Carlos Bianchi

    2010-03-01

    Full Text Available An evaluation was made of the abrasive wear of six composite thermofixed dental resins subjected to different polymerization times. The method of evaluation was based on sharpness measurements to quantify the abrasive wear resistance of the resins. To this end, a test bench was built, consisting of a rotating porcelain cylinder that wears out a resin-coated cylinder placed above it, thus causing vertical displacement of the contact as the wear progresses. The values of vertical displacement, i.e., the input variables, were read and recorded by means of a computer program to obtain the sharpness values. These data indicated that the resins displayed different behaviors as a function of the polymerization times applied, reinforcing the importance of using a practical and rapid method of analysis in order to ensure that the behavior of new materials is fully understood before they are launched on the market.

  5. Bond strength of resin composite to light activated bleached enamel

    African Journals Online (AJOL)

    2015-09-02

    , resin bonding, tooth bleaching. Date of Acceptance: ... The energy absorbed from the light accelerates the oxidation–reduction reaction.[12]. Bleaching treatment is frequently recommended before porcelain restorations or ...

  6. Isoconversional kinetic analysis of the alkyd/melamine resins curing

    Directory of Open Access Journals (Sweden)

    Jovičić Mirjana

    2013-01-01

    Full Text Available The curing reaction for the mixtures of alkyd resins based on ricinoleic acid, phthalic anhydride and three polyols (glycerin, trimethylolpropane or ethoxylated pentaerythritol with two different commercial melamine resins was investigated by differential scanning calorimetry (DSC. The curing kinetics analysis was performed using the isoconversional methods (Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman. Isoconversional methods were carried out with three heating rates (5, 10 and 20°C/min in a scanning temperature range from 40 to 250°C. It was found that the curing activation energy of resin mixtures is influenced by alkyd and melamine resin type due to the catalytic effect of hydroxyl group on the reactions. The dependence of apparent curing degree on time, which was obtained by mathematical transformations of dynamic DSC data using Ozawa-Flynn-Wall method, describes well the isothermal DSC experiments.

  7. CITRIC ACID FERMENTATION OF SUGARS PURIFIED WITH CHELATING RESIN1

    Science.gov (United States)

    Noguchi, Yuichi; Johnson, Marvin J.

    1961-01-01

    Noguchi, Yuichi (University of Wisconsin, Madison), and Marvin J. Johnson. Citric acid fermentation of sugars purified with chelating resin. J. Bacteriol. 82:538–541. 1961.—A new, independently isolated strain of Aspergillus niger capable of giving high yields of citric acid in submerged culture was found to show the same behavior toward iron, zinc, and manganese as a previously studied strain. Citric acid accumulation did not occur in the presence of manganese. Best citric acid production was obtained in the presence of limited amounts of iron and zinc. Use of a chelating ion exchange resin was found to be an excellent method of removing polyvalent metals from sugars, either for analytical purposes or for fermentation. Commercial glucose, after resin treatment, gave citric acid yields of more than 80% when supplemented with iron and zinc. Unpurified glucose was converted to citric acid in good yields by mycelium grown on resin-treated glucose. PMID:14480219

  8. Rheological characterization of geopolymer binder modified by organic resins

    Science.gov (United States)

    Cekalová, M.; Kovárík, T.; Rieger, D.

    2017-01-01

    The purpose of this study is going to investigate properties of alkali-activated powder (calcined kaoilinitic clay and granulated blast furnace slag) prepared as a geopolymer paste and modified by various amount of organic resin. Hybrid organic-inorganic binders were prepared as a mix of organic resin and geopolymer inorganic paste under vacuum conditions. The process of solidification was investigated by measurements of storage (G’) and loss modulus ( G’) in torsion. The measurement was conducted in oscillatory mode by constant strain of 0.01 %. This strain is set in linear visco-elastic region for minimization influence of paste structure. The effect of organic resin is presented and determined by changes of viscosity (‘n*), modules in torsion and tangent of loss angle (tan 8). Results indicate that addition of organic resin significantly affects the initial viscosity and hardening kinetics.

  9. Cure of epoxy resins determined by simple tests

    Science.gov (United States)

    Ladaki, M.; Nigh, W. G.

    1968-01-01

    Rapid visual and simple quantitative tests indicate the degree of cure of particular epoxy resin binders in prepreg stock. It is possible that these tests may be extended to a number of different epoxy formulations.

  10. Short Communication. Resin tapping activity as a contribution to the management of maritime pine forest

    Energy Technology Data Exchange (ETDEWEB)

    Palma, A.; Pereira, J.M.; Soares, P.

    2016-07-01

    Aim of the study: In this work potential resin yield in a region of high forest ability where maritime pine is the main species was estimated in order to understand the viability of promoting resin exploitation. Area of study: This study was conducted in Castro Da ire County in central region of Portugal. Material and methods: To quantify the resin yield of trees tapped for the first time two plots were installed in a maritime pine stand with average tree age 65 years. Before the beginning of the resin tapping, dendrometric tree variables were measured. Also, in a neighbouring stand, 25 trees were selected to check the relation between tree dbh and resin yield. Gum resin from every tree was weighted during the season. Estimates of potential resin yield in Castro Daire County were made based on data from National Forest Inventory plots, resin tapping legislation and resin yield values obtained in the field. Two scenarios were considered: high and low resin yield. To understand the intentions of forest owners towards restarting resin tapping activity 16 maritime pine forest owners were interviewed. Main results: The results point out a high yield potential capacity for gum resin production in the County: values between 2,025 and 5,873 tons were obtained. Research highlights: Results may highlight the important socio-economical role of the resin tapping activity and can be used to support national forest policies to the resin sector and give forest owners motivation to reactivate resin tapping activity. (Author)

  11. Vacuum assisted resin transfer molding (VARTM): Model development and verification

    Science.gov (United States)

    Song, Xiaolan

    2003-06-01

    In this investigation, a comprehensive Vacuum Assisted Resin Transfer Molding (VARTM) process simulation model was developed and verified. The model incorporates resin flow through the preform, compaction and relaxation of the preform, and viscosity and cure kinetics of the resin. The computer model can be used to analyze the resin flow details, track the thickness change of the preform, predict the total infiltration time and final fiber volume fraction of the parts, and determine whether the resin could completely infiltrate and uniformly wet out the preform. Flow of resin through the preform is modeled as flow through porous media. Darcy's law combined with the continuity equation for an incompressible Newtonian fluid forms the basis of the flow model. During the infiltration process, it is well accepted that the total pressure is shared by the resin pressure and the pressure supported by the fiber network. With the progression of the resin, the net pressure applied to the preform decreases as a result of increasing local resin pressure. This leads to the springback of the preform, and is called the springback mechanism. On the other side, the lubrication effect of the resin causes the rearrangement of the fiber network and an increase in the preform compaction. This is called the wetting compaction mechanism. The thickness change of the preform is determined by the relative magnitude of the springback and wetting deformation mechanisms. In the compaction model, the transverse equilibrium equation is used to calculate the net compaction pressure applied to the preform, and the compaction test results are fitted to give the compressive constitutive law of the preform. The Finite Element/Control Volume (FE/CV) method is adopted to find the flow front location and the fluid pressure. The code features the ability of simultaneous integration of 1-D, 2-D and 3-D element types in a single simulation, and thus enables efficient modeling of the flow in complex mold

  12. An Engineering Evaluation of Spherical Resorcinol Formaldehyde Resin

    Energy Technology Data Exchange (ETDEWEB)

    Birdwell Jr, Joseph F [ORNL; Lee, Denise L [ORNL; Taylor, Paul Allen [ORNL; Collins, Robert T [ORNL; Hunt, Rodney Dale [ORNL

    2010-09-01

    A small column ion exchange (SCIX) system has been proposed for removal of cesium from caustic, supernatant, and dissolved salt solutions stored or generated from high-level tank wastes at the US Department of Energy (DOE) Hanford Site and Savannah River Sites. In both instances, deployment of SCIX systems, either in-tank or near-tank, is a means of expediting waste pretreatment and dispositioning with minimal or no new infrastructure requirements. Conceptually, the treatment approach can utilize a range of ion exchange media. Previously, both crystalline silicotitanate (CST), an inorganic, nonelutable sorbent, and resorcinol-formaldehyde (RF), an organic, elutable resin, have been considered for cesium removal from tank waste. More recently, Pacific Northwest National Laboratory (PNNL) evaluated use of SuperLig{reg_sign} 644, an elutable ion exchange medium, for the subject application. Results of testing indicate hydraulic limitations of the SuperLig{reg_sign} resin, specifically a high pressure drop through packed ion exchange columns. This limitation is likely the result of swelling and shrinkage of the irregularly shaped (granular) resin during repeated conversions between sodium and hydrogen forms as the resin is first loaded then eluted. It is anticipated that a similar flow limitation would exist in columns packed with conventional, granular RF resin. However, use of spherical RF resin is a likely means of mitigating processing limitations due to excessive pressure drop. Although size changes occur as the spherical resin is cycled through loading and elution operations, the geometry of the resin is expected to effectively mitigate the close packing that leads to high pressure drops across ion exchange columns. Multiple evaluations have been performed to determine the feasibility of using spherical RF resin and to obtain data necessary for design of an SCIX process. The work performed consisted of examination of radiation effects on resin performance

  13. Urea-formaldehyde resins: production, application, and testing

    Science.gov (United States)

    Nuryawan, A.; Risnasari, I.; Sucipto, T.; Heri Iswanto, A.; Rosmala Dewi, R.

    2017-07-01

    Urea-formaldehyde (UF) resin, one of the most important formaldehyde resin adhesives, is a polymeric condensation product of formaldehyde with urea, and being widely used for the manufacture of wood-based composite panels, such as plywood, particleboard, and fiberboard. In spite of its benefits such as fast curing, good performance in the panels (colorless), and lower cost; formaldehyde emission (FE) originated from either UF resin itself or composite products bonded by UF resins is considered a critical drawback as it affects human health particularly in indoor environment. In order to reduce the FE, lowering formaldehyde/urea (F/U) mole ratio in the synthesis of the UF resin was done. In this study, synthesis of UF resins was carried out following the conventional alkaline-acid two-step reaction with a second addition of urea, resulting in F/U mole ratio around 1.0, namely 0.95; 1.05, and 1.15. The UF resins produced were used as binder for particleboard making. The board was manufactured in the laboratory using shaving type particle of Gmelina wood, 8% UF resin based on oven dry particle, and 1% NH4Cl (20%wt) as hardener for the resin. The target of the thickness was 10 mm and the dimension was 25 cm x 25 cm. The resulted particleboard then was evaluated the physical and the mechanical properties by Japanese Industrial Standard (JIS) A 5908 (2003). Further, the resulted particleboard also was used for the mice cage’s wall in order to mimic the real living environment. After four weeks exposure in the cages, the mice then were evaluated their mucous organs as well as their blood. The experiment results were as follows: 1) It was possible to synthesis UF resins with low F/U mole ratio; 2) However, the particleboard bonded UF resins with low F/U mole ratio showed poor properties, particularly on the thickness swelling and modulus of elasticity; 3) There was no significant differences among the mucous organs of the mice after a month exposure FE originated from

  14. Surface discoloration of composite resins: Effects of staining and bleaching.

    Science.gov (United States)

    Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

    2012-09-01

    The purpose of this in vitro study was to evaluate surface discoloration of three microhybrid composite resins (Esthet•X HD, Clearfil AP-X, Gradia Direct) and five nanohybrid composite resins (Ceram•X, GC Kalore, G-aenial, Grandio, GrandioSO), after staining and bleaching procedures. The composite resins were polymerized with a curing light (Celalux II, Voco, Cuxhaven, Germany) into 160 silicon molds (6,4 mm in diameter and 2 mm in thickness) to obtain identical specimens. Twenty samples for each composite resin were prepared. The specimens were polished using an automated polishing machine with the sequence of 600-, 800-, 1000-grit abrasive paper under water irrigation. The specimens were immersed in tea and distilled water: the specimens were dipped for 20 min, once a day (every 24 h), for 14 days into the drinks. The specimens were then bleached with carbamide peroxide at 17% (Perfect Bleach-Voco). The color of specimens was measured with a spectrophotometer according to the CIE L(*)a(*)b(*) system after light-polymerization of composite resin specimens, after 7 days, after 14 days, and after bleaching. The color difference h index (DEab(*)) between each measurement was calculated. Statistical analysis was made using analysis of variance (ANOVA). All specimens showed a significant increase in staining with a similar trend and no significant differences between microhybrid and nanohybrid composite resins. After whitening procedures, materials tested showed both significant and unsignificant differences of the h index. Microhybrid and nanohybrid composite resins had similar in vitro surface discoloration in tea. After bleaching, discoloration was removed from some composite resins tested.

  15. Surface discoloration of composite resins: Effects of staining and bleaching

    Directory of Open Access Journals (Sweden)

    Claudio Poggio

    2012-01-01

    Full Text Available Background: The purpose of this in vitro study was to evaluate surface discoloration of three microhybrid composite resins (Esthet·X HD, Clearfil AP-X, Gradia Direct and five nanohybrid composite resins (Ceram·X, GC Kalore, G-aenial, Grandio, GrandioSO, after staining and bleaching procedures. Materials and Methods: The composite resins were polymerized with a curing light (Celalux II, Voco, Cuxhaven, Germany into 160 silicon molds (6,4 mm in diameter and 2 mm in thickness to obtain identical specimens. Twenty samples for each composite resin were prepared. The specimens were polished using an automated polishing machine with the sequence of 600-, 800-, 1000-grit abrasive paper under water irrigation. The specimens were immersed in tea and distilled water: the specimens were dipped for 20 min, once a day (every 24 h, for 14 days into the drinks. The specimens were then bleached with carbamide peroxide at 17% (Perfect Bleach-Voco. The color of specimens was measured with a spectrophotometer according to the CIE LFNx01aFNx01bFNx01 system after light-polymerization of composite resin specimens, after 7 days, after 14 days, and after bleaching. The color difference h index (DE abFNx01 between each measurement was calculated. Statistical analysis was made using analysis of variance (ANOVA. Results: All specimens showed a significant increase in staining with a similar trend and no significant differences between microhybrid and nanohybrid composite resins. After whitening procedures, materials tested showed both significant and unsignificant differences of the h index. Conclusions: Microhybrid and nanohybrid composite resins had similar in vitro surface discoloration in tea. After bleaching, discoloration was removed from some composite resins tested.

  16. Characterization and Process Development of Cyanate Ester Resin and Composite

    Energy Technology Data Exchange (ETDEWEB)

    Frame, B.J.

    1998-03-01

    Cyanate ester (or polycyanate) resins offer advantages as composite matrices because of their high thermal stability, low outgassing, low water absorption and radiation resistance. This report describes the results of a processing study to develop high-strength hoop-wound composite by the wet-filament winding method using Toray T1000G carbon fiber and YLA RS-14A polycyanate resin as the constituent materials. Process trials, tests and analyses were conducted in order to gain insight into factors that can affect final properties of the cured cyanate ester resin and its composites. The study shows that the cyanate ester resin has a broad process envelope but that an inert-atmosphere cure is essential for obtaining optimum resin and composite properties. Minimizing moisture exposure prior to cure is also crucial as it affects the T{sub g} of the resin and composite. Recommendations for reducing moisture contact with the resin during wet-winding are presented. High fiber volume fraction ({approximately}80%) composites wound and cured with these methods yielded excellent hoop tensile strengths (660 to 670 ksi average with individual rings failing above 700 ksi), which are believed to be the highest recorded strengths for this class of materials. The measured transverse properties were also exceptional for these high fiber fraction composites. Based on the available data, this cyanate ester resin system and its composites are recommended for space and vacuum applications only. Further testing is required before these materials can be recommended for long term use at elevated temperatures in an ambient air environment. The results of all analyses and tests performed as part of this study are presented as well as baseline process for fabricating thick, stage-cured composites. The manufacture of a 1 in. thick composite cylinder made with this process is also described.

  17. Selective flotation of fossil resin from Western coal

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, G.F.; Miller, J.D.

    1991-10-15

    Technical activities for the fourth quarter involved efforts by both the University of Utah and Advanced Processing Technologies, Inc. Laboratory research at the University of Utah was primarily concerned with surface chemistry/resin characterization, which has emphasized Fourier transform infrared analysis in the past quarter. APT's major activities included proof-of-concept plant testing of the fossil resin flotation circuit. (VC)

  18. Branched polymeric media: Perchlorate-selective resins from hyperbranched polyethyleneimine

    KAUST Repository

    Chen, Dennis P.

    2012-10-02

    Perchlorate (ClO4 -) is a persistent contaminant found in drinking groundwater sources in the United States. Ion exchange (IX) with selective and disposable resins based on cross-linked styrene divinylbenzene (STY-DVB) beads is currently the most commonly utilized process for removing low concentrations of ClO4 - (10-100 ppb) from contaminated drinking water sources. However, due to the low exchange capacity of perchlorate-selective STY-DVB resins (∼0.5-0.8 eq/L), the overall cost becomes prohibitive when treating groundwater with higher concentration of ClO4 - (e.g., 100-1000 ppb). In this article, we describe a new perchlorate-selective resin with high exchange capacity. This new resin was prepared by alkylation of branched polyethyleneimine (PEI) beads obtained from an inverse suspension polymerization process. Batch and column studies show that our new PEI resin with mixed hexyl/ethyl quaternary ammonium chloride exchange sites can selectively extract trace amounts of ClO4 - from a makeup groundwater (to below detection limit) in the presence of competing ions. In addition, this resin has a strong-base exchange capacity of 1.4 eq/L, which is 1.75-2.33 times larger than those of commercial perchlorate-selective STY-DVB resins. The overall results of our studies suggest that branched PEI beads provide versatile and promising building blocks for the preparation of perchlorate-selective resins with high exchange capacity. © 2012 American Chemical Society.

  19. Optimizing preparation design for metal-free composite resin crowns.

    Science.gov (United States)

    Ohlmann, Brigitte; Gruber, Rudolf; Eickemeyer, Grit; Rammelsberg, Peter

    2008-09-01

    Although composite resin materials are used for posterior crown restorations, the influence of preparation design, material thickness, convergence angle, and method of cementation on fracture resistance remains unclear. The purpose of this in vitro study was to test the hypothesis that minimal preparation designs provide an acceptable level of fracture resistance for posterior composite resin crowns. Nonreinforced Artglass composite resin crowns (n=128) were fabricated on human molars in 16 test groups (n=8). Axial tooth preparation included a 1-mm-deep shoulder or a 0.5-mm chamfer preparation, whereas occlusal reduction was either 0.5 mm or 1.3 mm. The total angle of convergence was 4 or 11 degrees and the crowns were cemented either with glass ionomer cement (Ketac Cem) or resin cement (2bond2). After 10,000 thermal cycles, crowns were vertically loaded until failure occurred; load was measured in newtons. Statistical analysis was performed by a 4-way ANOVA (alpha=.05). Statistical analysis revealed significant effects of occlusal thickness (Pcrowns. For composite resin crowns with an occlusal thickness of 0.5 mm, the resistance to fracture was lower than for crowns with a 1.3-mm thickness. Fracture resistance was greater when resin cement was used, and greater for the chamfer finish line than for the shoulder finish line. Use of a greater total convergence angle reduced fracture resistance. Fracture resistance of composite resin crowns was significantly improved by increasing the occlusal thickness of the crowns, by using resin cement, and by reducing the total convergence angle.

  20. Properties of Graphene Oxide/Epoxy Resin Composites

    OpenAIRE

    Jijun Tang; Haijun Zhou; Yunxia Liang; Xinlan Shi; Xin Yang; Jiaoxia Zhang

    2014-01-01

    The graphene oxide (GO) was obtained by pressurized oxidation method using natural graphite as raw materials. Then the GO/epoxy resin composites were prepared by casting. The mechanical and damping properties of composites were studied. As a result, the impact intensity of GO/epoxy resin composites was prominently improved with the content of the graphene oxide increasing. The glass transition temperature decreased and the damping capacity is improved.

  1. Sustainable, Green Vinyl Ester Resin (VER) from Renewable Resources

    Science.gov (United States)

    2017-04-02

    most important building blocks of today’s plastics industry. Many plastics such as polycarbonates, epoxy resins, and vinyl ester resins are synthesized...the reaction was performed in a reactor sealed with a plastic cork. Several reactions were performed, mainly by varying phenol-to-acetone ratio...wastes of cooked oil, rice straw , vegetable oil mixtures of cottonseed, soybean and castor oils, jatropha oil, and crude palm oil. Biodiesel is

  2. PEMBUATAN GIGI TIRUAN LEPASAN DENGAN MENGGUNAKAN RESIN VISIBLE LIGHT CURE

    OpenAIRE

    RIADIANTORO, ALFIAN

    2012-01-01

    2011 Dewasa ini perkembangan teknologi dalam ilmu kedokteran gigi semakin canggih, dalam ilmu bahan kedokteran gigi banyak penemuan baru yang ditemukan seperti halnya acrylic resin. Acrylic resin selalu menggunakan Polymethil Acrilate (PMMA) jenis polimerisasi heat cure dengan cara merebus samapai dengan 8-12 jam pada temperatur 74 C, 2 jam 100 c, dan menggunakan oven microwave pada 15-20 menit dengan kekuatan listrik 25 watt. Sekarang diperkenalkan bahan baru yang lebih efektif dan efis...

  3. Artificial saliva effect on toxic substances release from acrylic resins

    OpenAIRE

    Kostić Milena; Krunić Nebojša; Najman Stevo; Nikolić Ljubiša; Nikolić Vesna; Rajković Jelena; Petrović Milica; Igić Marko; Ignjatović Aleksandra

    2015-01-01

    Background/Aim. Acrylic-based resins are intensively used in dentistry practice as restorative or denture-base materials. The purpose of this study was to analyze the surface structure of denture base resins and the amount of released potentially toxic substances (PTS) immediately upon polymerization and incubation in different types of artificial saliva. Methods. Storage of acrylic samples in two models of artificial saliva were performed in a water bath a...

  4. Moessbauer Study of Discoloration of Synthetic Resin Covered Electric Switches

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmann, E. [Eoetvoes University, Department of Nuclear Chemistry (Hungary); Muzsay, I.; Homonnay, Z. [Taurus EMERGE, Rubber Industrial Ltd (Hungary); Vertes, A. [Eoetvoes University, Department of Nuclear Chemistry (Hungary)

    2002-03-15

    {sup 57}Fe Moessbauer spectroscopy and X-ray diffractometry were used to investigate brown discoloration and sediments formed on the surface of synthetic resin product covered electronic switches. The Moessbauer measurement revealed that alloyed steels and iron-containing corrosion products are associated with the discolored layers. Iron, and iron corrosion products were shown by both MS and XRD in the sediments formed eventually during the finishing of the synthetic resin products after machining and washing with water solution.

  5. Preparation of montmorillonite modified phenolic resin for shell process

    OpenAIRE

    Xiong Jianmin; Li Yuancai; Wang Wenqing

    2009-01-01

    The development of montmorillonite modified phenolic resin under microwave irradiation heating was investigated. The effect of montmorillonite content and stirring time on the structure and morphology of synthetic resin was analyzed. The optimum processing procedure was found to be 45 min stirring time with 5.4% montmorillonite addition. Further, the platelet spacing increases with stirring time till montmorillonite exfoliated to nanoscales platelet. When montmorillonite is exfoliated, layere...

  6. Gastroprotective activity of the resin from Virola oleifera.

    Science.gov (United States)

    Pereira, Ana Claudia Hertel; Lenz, Dominik; Nogueira, Breno Valentim; Scherer, Rodrigo; Andrade, Tadeu Uggere; Costa, Helber Barcellos da; Romão, Wanderson; Pereira, Thiago Melo Costa; Endringer, Denise Coutinho

    2017-12-01

    The resin from the trunk wood of Virola oleifera (Schott) A. C. Smith (Myristicaceae) is used in folk medicine to hasten wound repair and to treat pain and inflammatory conditions, and our previous report indicated the anti-oxidative properties in other oxidative stress model. To investigate the protective effects of resin from V. oleifera in two experimental models of gastric ulcer oxidative-stress dependent. Plant material was collected and the resin was subjected to partitioning with organic solvents. The buthanol fraction was subjected to chromatographic and spectrometric methods for isolation and structural elucidation. The resin was quantified for polyphenols and flavonoids by colorimetric methods. Furthermore, the antioxidant activity of resin was determined by three different methods. The ulcers were induced acutely in Swiss male mice with ethanol/HCl and indomethacin using single-doses of 10 and 100 mg/kg. The gastroprotection of the experimental groups was comparable to reference control lansoprazole (3 mg/kg). The high content of polyphenols (∼82%) and the presence of epicatechin and eriodictyol were determined. The LD 50 was estimated at 2500 mg/kg. At minimum (10 mg/kg) and maximum (100 mg/kg) dosage of resin, both in ethanol/HCl as indomethacin ulcer induction models demonstrate reduction of lesions (minimum: ∼97% and ∼66%; maximum: ∼95% and ∼59%). The gastroprotection might be related to tannins, phenolic acids and flavonoids present in the resin by antioxidant properties. The results indicate that this resin has gastroprotective activity probably associated with the presence of phenolic antioxidant substances.

  7. Affordable Resins and Adhesives From Optimized Soybean Varieties (ARA Program)

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Richard WOol; Dr. X. Susan Sun; Rich Chapas

    2004-04-21

    The Mission of the ARA Program was to develop the Corporate Infrastructure to mass-produce new bio-based materials from Soybeans. The resins were integrated with the bio-fuels program. (1) to research, develop, and commercialize low cost adhesives and resins from soy oil and protein, the co-products of the soy bio-diesel process. (2) to study structure-functionality of soy oil and proteins at molecular and genomic levels

  8. Marginal adaptation of ceramic restorations inserted with different luting resins

    OpenAIRE

    Friedrich, Insa

    2010-01-01

    The demand for esthetic tooth coloured restorations has been arising in the last years. For larger cavities indirect ceramic restaurations are used. In order to reduce the insertion time and to avoid the time-consuming total etch technique, self etching primer and self curing resin cement systems were developed. The purpose of this study was to analyze the quality of marginal adaptation after using the different primer/resin cement systems. 72 extracted teeth were stored in 0,1% thymol...

  9. Orthodontic treatment finishing with minimally invasive resin composite veneers.

    OpenAIRE

    Maenosono, Rafael Massunari; Department of Operative Dentistry, Endodontics and Dental Materials – Bauru School of Dentistry – University of São Paulo – Bauru – São Paulo – Brazil.; Ramos, Carla Muller; Department of Operative Dentistry, Endodontics and Dental Materials – Bauru School of Dentistry – University of São Paulo – Bauru – São Paulo – Brazil.; Brianezzi, Letícia Ferreira de Freitas; Department of Operative Dentistry, Endodontics and Dental Materials – Bauru School of Dentistry – University of São Paulo – Bauru – São Paulo – Brazil.; Oda, Denise Ferracioli; Department of Operative Dentistry, Endodontics and Dental Materials – Bauru School of Dentistry – University of São Paulo – Bauru – São Paulo – Brazil.; Mondelli, Rafael Francisco Lia; Department of Operative Dentistry, Endodontics and Dental Materials – Bauru School of Dentistry – University of São Paulo – Bauru – São Paulo – Brazil.; Ishikiriama, Sérgio Kiyoshi; Department of Operative Dentistry, Endodontics and Dental Materials – Bauru School of Dentistry – University of São Paulo – Bauru – São Paulo – Brazil.

    2015-01-01

    Anatomic alterations caused by incisal guide wear, even being small, cause the aspect of an aged smile. The objective of this clinical case is to report a highly conservative esthetical treatment, performed through the association of in-office bleaching and resin composite veneers. In-office bleaching was performed with 35% hydrogen peroxide, and in the following week minimal invasive resin composite veneers were implemented on upper incisors and canines. In the next appointment, finishing an...

  10. Cantilever Resin-Bonded Fixed Dental Prostheses Show Clinical Success

    Science.gov (United States)

    2018-03-26

    FROM: 59 MDW/SGVU SUBJECT: Professional Presentation Approval 16 MAR 2017 1. Your paper, entitled Cantilever Resin-Bonded Fixed Dental Prosthesis ...Show Clinical Success presented at/published to Texas Dental Journal in accordance with MDWI 41- 108, has been approved and assigned local file #17147...resin-bonded lixed dental prostheses show clinical success 7. FUNDING RECEIVED FOR THIS STUDY? 0 YES [gj NO FUNDING SOURCE: 8. DO YOU NEED FUNDING

  11. High char imide-modified epoxy matrix resins

    Science.gov (United States)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D.

    1979-01-01

    Studies were performed to synthesize a novel class of bis (imide-amine) curing agents for epoxy matrix resins. Glass transition temperatures and char yield data of an epoxy cured with various bis (imide-amines) are presented. The room temperature and 350 F mechanical properties, and char yields of unidirectional graphite fiber laminates prepared with conventional epoxy and imide-modified epoxy resins are presented.

  12. Clinical performance of a hybrid resin composite with and without an intermediate layer of flowable resin composite: a 7-year evaluation

    DEFF Research Database (Denmark)

    van Dijken, Jan W V; Pallesen, Ulla

    2011-01-01

    The objective of this prospective clinical follow up was to evaluate the long term clinical performance of a hybrid resin composite in Class II restorations with and without intermediate layer of flowable resin composite.......The objective of this prospective clinical follow up was to evaluate the long term clinical performance of a hybrid resin composite in Class II restorations with and without intermediate layer of flowable resin composite....

  13. Relationship between Color and Translucency of Multishaded Dental Composite Resins

    Directory of Open Access Journals (Sweden)

    Homan Naeimi Akbar

    2012-01-01

    Full Text Available The aim of the present study was to compare the translucency of different shades of two highly aesthetic multilayered restorative composite resins. In total nine shades from Esthet.X and ten shades from Filtek Supreme composite resins were chosen. Discs of each shade were prepared (N=3 and light-cured. Total and diffuse transmittance values for each sample were measured. Statistical analysis showed that the opaque dentine shades of both composites were the least translucent and the enamel shades had the highest translucency. There was a significant decrease in translucency from A2 to C2 of regular body shades and also from A4 to C4 of opaque dentine shades of Esthet.X composite resin. Grey enamel shade had a significantly higher diffuse translucency compared to clear and yellow enamel shades. There was a significant decrease in translucency from A2B to D2B and also in diffuse translucency from A4D to C6D shades of Filtek Supreme composite resin. It can be concluded that the color of the composite resins tested in this study had a significant effect on their translucency. Information on the translucency of different shades of composite resins can be very useful for the clinicians in achieving optimal esthetic restorative outcome.

  14. Timing for composite resin placement on mineral trioxide aggregate.

    Science.gov (United States)

    Tsujimoto, Masaki; Tsujimoto, Yasuhisa; Ookubo, Atsushi; Shiraishi, Takanobu; Watanabe, Ikuya; Yamada, Shizuka; Hayashi, Yoshihiko

    2013-09-01

    The aim of this study was to investigate the proper time to restore composite resin over mineral trioxide aggregate (MTA). Thirty-five samples of MTA blocks were divided into 7 groups with 3 different times (10 minutes, 1 day, and 7 days) selected for restoring the composite resin over MTA with and without bonding resin, and a control group was included for comparison. After 21 days, the distances between MTA and the composite resin or between MTA and the bonding agent on sectioned planes along the long axis were measured using a scanning electron microscope (×2,000 magnification). The hardness of the MTA near the composite resin was presented as the Vickers microhardness. There were no gaps at the interface in the 10-minute groups, the 1-day group with a bonding agent, and the 7-day group with a bonding agent. The groups without a bonding agent at 1 and 7 days presented a separation or gap at the interface. The value of the Vickers microhardness in the 1-day groups was significantly decreased compared with those of the other groups regardless of the presence or absence of a bonding agent. These findings suggest that composite resin with a bonding agent over MTA can be restored almost immediately after MTA mixing during a single visit. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  15. Androecia in two Clusia species: development, structure and resin secretion.

    Science.gov (United States)

    Sá-Haiad, B; Silva, C P; Paula, R C V; Rocha, J F; Machado, S R

    2015-07-01

    Clusia fluminensis and C. lanceolata are dioecious shrubs having resiniferous flowers with strongly distinct androecia. The aim of this study was to investigate the development and anatomy of their androecia and the ultrastructure, histochemistry and secretory process of their androecium resin glands, examining whether the cellular aspects of resin secretion differed between these two morphologically distinct androecia. Stamens differ, being free in C. fluminensis and clustered in a synandrium in C. lanceolata. Staminode sterility is due to the undifferentiated nature of the anthers in C. lanceolata and degeneration of meiocytes and anther indehiscence in C. fluminensis. Resin is produced in subepidermal cavities and canals with wide lumens. In the secretory stage, epithelial cells present sinuous walls, voluminous nuclei, polymorphic plastids associated with periplastidial reticulum, mitochondria, oil bodies, multivesicular bodies, endoplasmic reticulum and dictyosomes. The resin is released through rupture points on the distal surface of stamens and staminodes, associated with disrupted cavities and canals. Our results show morphological diversity associated with functional similarity. Also, a secretion pattern shared by the two species includes initiation of the secretory process in young floral buds, compartmentalisation of the secretion in pre-anthesis buds and release of secretions at anthesis. Cellular aspects of resin secretion in these species are quite similar, as are the chemical identities of the main components of the floral resins of the genus. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

  16. Preparative Purification of Liriodendrin from Sargentodoxa cuneata by Macroporous Resin

    Science.gov (United States)

    Li, Di-Hua; Wang, Yan; Lv, Yuan-Shan; Liu, Jun-Hong; Yang, Lei; Zhang, Shu-Kun; Zhuo, Yu-Zhen

    2015-01-01

    The preparative purification of liriodendrin from Sargentodoxa cuneata using macroporous resin combined with crystallization process was evaluated. The properties of adsorption/desorption of liriodendrin on eight macroporous resins were investigated systematically. X-5 resin was selected as the most suitable medium for liriodendrin purification. The adsorption of liriodendrin on X-5 resin fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model. Dynamic adsorption/desorption tests were performed using a glass column packed with X-5 resin to optimize the separation process of liriodendrin. After one treatment with X-5 resin, the content of liriodendrin in the product was increased 48.73-fold, from 0.85% to 41.42%, with a recovery yield of 88.9%. 97.48% liriodendrin was obtained by further crystallization and determined by HPLC. The purified product possessed strong antioxidant activity. In conclusion, purification of liriodendrin might expend its further pharmacological researches and further applications in pharmacy. PMID:26236742

  17. Thermal Study of Anhydrides Cured Tetrafunctional Cardo Epoxy Resin

    Directory of Open Access Journals (Sweden)

    Jignesh P. Patel

    2013-01-01

    Full Text Available Tetrafunctional cardo epoxy resin (EBCF was cured by using 10 wt% maleic anhydride (MA, pyromellitic dianhydride (PMDA, phthalic anhydride (PA, tetrahydrophthalic anhydride (THPA, tetrabromophthalic anhydride (TBPA, and tetrachlorophthalic anhydride (TCPA as hardeners at 120°C for 40–105 min (gel time and then postcured 1 h at 130°C. Gel time is found to depend on the structure of the anhydrides used. Cured samples were found insoluble in common solvents. Cured and uncured EBCF were characterized by FTIR, DSC, and TGA techniques. Cured and uncured resins followed multistep degradation reactions. Kinetic parameters, namely, order of degradation, energy of activation, frequency factor, and entropy change, were determined according to the Anderson-Freeman method and interpreted in light of the nature of hardeners used for curing purpose. The resins followed integral or fractional order degradation kinetics. Complex degradation reactions are due to different types of linkages in cured resins. Both nature and structure of resin and hardeners affected the curing behavior and the resultant thermal properties of the cured resins.

  18. Analysis of surface hardness of artificially aged resin composites

    Directory of Open Access Journals (Sweden)

    Denise Cremonezzi Tornavoi

    2012-02-01

    Full Text Available This study evaluated the effect of artificially accelerated aging (AAA on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05, ANOVA and Tukey test (p < 0.05. With regard to hardness (F = 86.74, p < 0.0001 the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53. In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002. It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

  19. Fiber reinforced silicon-containing arylacetylene resin composites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available A silicon-containing arylacetylene resin (SAR, a poly(dimethylsilyleneethynylene phenyleneethynylene (PMSEPE, was synthesized. The PMSEPE is a solid resin at ambient temperature with a softening temperature about 60°C and soluble in some solvents like tetrahydrofuran. The melt viscosity of the PMSEPE resin is less than 1 Pa•s. The resin could cure at the temperature of lower than 200°C. Fiber reinforced PMSEPE composites were prepared from prepregs which were made by the impregnation of fibers in PMSEPE resin solution. The composites exhibit good mechanical properties at room temperature and 250°C. The observation on fracture surfaces of the composites reinforced by glass fibers and carbon fibers demonstrates that the adhesion between the fibers and resin is good. The results from an oxyacetylene flame test show that the composites have good ablation performance and XRD analyses indicate that SiC forms in the residues during the ablation of the composites.

  20. Resin-based composites and compomers in primary molars.

    Science.gov (United States)

    García-Godoy, F

    2000-07-01

    Resin-based composite resins and polyacid-modified resin-based composites (compomers) have become popular for the restoration of primary anterior and posterior teeth. In some European countries, resin-based composites or glass-ionomers are the materials of choice for primary teeth because of the controversy over dental amalgam and its alleged adverse health effects resulting from the release of mercury, although a clear correlation between amalgam restorations and health has not been determined. Another reason for the worldwide increased use of resin-based composites and glass-ionomers in pediatric dentistry could be attributed to the growing demand from parents to provide esthetic restorations to their children. More conservative preparations can be performed maintaining more tooth structure because of the adhesive properties of the composites and compomers. The most conservative treatment planning and meticulous care in the placement of the resin-based composites and compomers would produce long-term satisfactory results. These restorations should be placed in patients with low-to-moderate caries risk, and after placement the restorations should be monitored carefully to avoid complications mainly produced by recurrent caries and wear.

  1. A mechanistic study of Protein A chromatography resin lifetime.

    Science.gov (United States)

    Jiang, Canping; Liu, Jing; Rubacha, Michael; Shukla, Abhinav A

    2009-07-31

    A mechanistic study into Protein A chromatographic resin lifetime limitations is presented. Binding and mass transport properties of two widely used agarose-based Protein A resins were studied to distinguish between the roles of resin fouling due to product/impurity build-up and ligand degradation as contributory factors towards the decline in binding capacity with use. Cycling studies were conducted with and without product loading on the columns to separate out the influence of resin fouling. Ligand degradation under the mildly alkaline conditions used for column regeneration was determined to be the primary cause for Protein A resin capacity decline with usage. The use of lower concentrations of caustic and the use of stabilizing excipients to protect the Protein A ligand during cleaning and sanitization were found to be useful techniques in maintaining column performance. The results presented in this paper provide a clearer understanding of the causative factors that limit Protein A chromatographic resin lifetime. It is anticipated that these findings will assist in the development of more robust and economical downstream manufacturing processes for monoclonal antibody and Fc fusion protein purification.

  2. Direct composite resin layering techniques for creating lifelike CAD/CAM-fabricated composite resin veneers and crowns.

    Science.gov (United States)

    LeSage, Brian

    2014-07-01

    Direct composite resin layering techniques preserve sound tooth structure and improve function and esthetics. However, intraoral placement techniques present challenges involving isolation, contamination, individual patient characteristics, and the predictability of restorative outcomes. Computer-aided design and computer-aided manufacturing (CAD/CAM) restorations enable dentists to better handle these variables and provide durable restorations in an efficient and timely manner; however, milled restorations may appear monochromatic and lack proper esthetic characteristics. For these reasons, an uncomplicated composite resin layering restoration technique can be used to combine the benefits of minimally invasive direct restorations and the ease and precision of indirect CAD/CAM restorations. Because most dentists are familiar with and skilled at composite resin layering, the use of such a technique can provide predictable and highly esthetic results. This article describes the layered composite resin restoration technique. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  3. Methyl Jasmonate Induces Traumatic Resin Ducts, Terpenoid Resin Biosynthesis, and Terpenoid Accumulation in Developing Xylem of Norway Spruce Stems

    National Research Council Canada - National Science Library

    Diane Martin; Dorothea Tholl; Jonathan Gershenzon; Jörg Bohlmann

    2002-01-01

    Norway spruce (Picea abies L. Karst) produces an oleoresin characterized by a diverse array of terpenoids, monoterpenoids, sesquiterpenoids, and diterpene resin acids that can protect conifers against potential herbivores and pathogens...

  4. Influence of Surface Modifications of Acrylic Resin Teeth on Shear Bond Strength with Denture Base Resin-An Invitro Study

    Science.gov (United States)

    Krishnan, Madhusudan; Krishnan, Chitra Shankar; Azhagarasan, N.S.; Sampathkumar, Jayakrishnakumar; Ramasubramanian, Hariharan

    2015-01-01

    Background Debonding of artificial teeth from the denture base is an important issue for edentulous patients rehabilitated with conventional or implant supported complete dentures. Aim The purpose of this study was to evaluate shear bond strength between denture base resin and acrylic resin denture teeth subjected to three different surface modifications on the ridge lap area as compared to unmodified denture teeth. Materials and Methods Forty acrylic resin central incisor denture teeth were selected and randomly divided into four test groups. The teeth in each group were subjected to one of the three different surface modifications, namely, chemical treatment, sandblasting and placement of retentive grooves on the ridge lap area respectively, prior to packing of the denture base resin. The group with unmodified teeth served as control. Forty acrylic resin test blocks thus obtained were tested for shear bond strength between acrylic resin teeth and denture base resin in Universal Testing Machine. Data obtained was statistically analysed using one-way ANOVA and Student- Newman- Keul’s test (pshear bond strength revealed that retentive grooves on the ridge lap area showed highest bond strength values followed by sandblasting and both were statistically significant compared to the control and chemically treated groups. Unmodified surface of the resin teeth showed the least bond strength. Conclusion Within the limitations of this invitro study the placement of retentive grooves or sandblasting of the ridge lap area showed highly significant improvement in shear bond strength compared to the unmodified surface. Chemical treatment did not result in any significant improvement in the shear bond strength compared to the unmodified surface. PMID:26501005

  5. Comparison of the Amount of Fluoride Release from Nanofilled Resin Modified Glass Ionomer Conventional and Resin Modified Glass Ionomer Cements

    Directory of Open Access Journals (Sweden)

    Sumitha Upadhyay

    2013-01-01

    Full Text Available Objective: To investigate and compare the amount of fluoride release of conventional, resin modified and nanofilled resin modified glass ionomer cements.Materials and Methods: Tablets of glass-ionomer cements were immersed in deionized water and incubated at 37◦C. After 1, 2, 7, 15 and 30 days, fluoride ion was measured under normal atmospheric conditions by fluoride ion selective electrode. Buffer (TISAB II was used to decomplex the fluoride ion and to provide a constant background ionic strength and to maintain the pH of water between 5.0 and 5.5 as the fluoride electrode is sensitive to changes in pH. Statistical evaluation was carried out by one way ANOVA (Analysis of Variance using SPSS 11.0. The significance level was set at p< 0.05.Results: The release of fluoride was highest on day 1 and there was a sudden fall on day 2 in all three groups. Initially fluoride release from conven-tional glass-ionomer cement was highest compared to the other two glass-ionomer cements, but the amount drastically reduced over the period. Although the amount of fluoride release was less than both the resin modified and nanofilled resin modified glass-ionomer cement, the release was sustained consistently for 30 daysConclusion: The cumulative fluoride release of nanofilled resin modified glass ionomer cement was very less compared to the conventional and resin modified glass ionomer cements and Nanofilled resin modified glass ionomer cement released less but steady fluoride as compared to other resin modified glass ionomer cements.

  6. Methyl Jasmonate Induces Traumatic Resin Ducts, Terpenoid Resin Biosynthesis, and Terpenoid Accumulation in Developing Xylem of Norway Spruce Stems1

    Science.gov (United States)

    Martin, Diane; Tholl, Dorothea; Gershenzon, Jonathan; Bohlmann, Jörg

    2002-01-01

    Norway spruce (Picea abies L. Karst) produces an oleoresin characterized by a diverse array of terpenoids, monoterpenoids, sesquiterpenoids, and diterpene resin acids that can protect conifers against potential herbivores and pathogens. Oleoresin accumulates constitutively in resin ducts in the cortex and phloem (bark) of Norway spruce stems. De novo formation of traumatic resin ducts (TDs) is observed in the developing secondary xylem (wood) after insect attack, fungal elicitation, and mechanical wounding. Here, we characterize the methyl jasmonate-induced formation of TDs in Norway spruce by microscopy, chemical analyses of resin composition, and assays of terpenoid biosynthetic enzymes. The response involves tissue-specific differentiation of TDs, terpenoid accumulation, and induction of enzyme activities of both prenyltransferases and terpene synthases in the developing xylem, a tissue that constitutively lacks axial resin ducts in spruce. The induction of a complex defense response in Norway spruce by methyl jasmonate application provides new avenues to evaluate the role of resin defenses for protection of conifers against destructive pests such as white pine weevils (Pissodes strobi), bark beetles (Coleoptera, Scolytidae), and insect-associated tree pathogens. PMID:12114556

  7. Apparatus and method for removing solvent from carbon dioxide in resin recycling system

    Science.gov (United States)

    Bohnert, George W [Harrisonville, MO; Hand, Thomas E [Lee's Summit, MO; DeLaurentiis, Gary M [Jamestown, CA

    2009-01-06

    A two-step resin recycling system and method solvent that produces essentially contaminant-free synthetic resin material. The system and method includes one or more solvent wash vessels to expose resin particles to a solvent, the solvent contacting the resin particles in the one or more solvent wash vessels to substantially remove contaminants on the resin particles. A separator is provided to separate the solvent from the resin particles after removal from the one or more solvent wash vessels. The resin particles are next exposed to carbon dioxide in a closed loop carbon dioxide system. The closed loop system includes a carbon dioxide vessel where the carbon dioxide is exposed to the resin, substantially removing any residual solvent remaining on the resin particles after separation. A separation vessel is also provided to separate the solvent from the solvent laden carbon dioxide. Both the carbon dioxide and the solvent are reused after separation in the separation vessel.

  8. Ultrafiltration Membrane Fouling and the Effect of Ion Exchange Resins

    KAUST Repository

    Jamaly, Sanaa

    2011-12-01

    Membrane fouling is a challenging process for the ultrafiltration membrane during wastewater treatment. This research paper determines the organic character of foulants of different kinds of wastewater before and after adding some ion exchange resins. Two advanced organic characterization methods are compared in terms of concentration of dissolved organic carbons: The liquid chromatography with organic carbon (LC-OCD) and Shimadzu total organic carbon (TOC). In this study, two secondary wastewater effluents were treated using ultrafiltration membrane. To reduce fouling, pretreatment using some adsorbents were used in the study. Six ion exchange resins out of twenty were chosen to compare the effect of adsorbents on fouling membrane. Based on the percent of dissolved organic carbon’s removal, three adsorbents were determined to be the most efficient (DOWEX Marathon 11 anion exchange resin, DOWEX Optipore SD2 polymeric adsorbent, and DOWEX PSR2 anion exchange), and three other ones were determined to the least efficient (DOWEX Marathon A2 anion exchange resin, DOWEX SAR anion exchange resin, and DOWEX Optipore L493 polymeric adsorbent). Organic characterization for feed, permeate, and backwash samples were tested using LC-OCD and TOC to better understand the characteristics of foulants to prevent ultrafiltration membrane fouling. The results suggested that the polymeric ion exchange resin, DOWEX SD2, reduced fouling potential for both treated wastewaters. All the six ion exchange resins removed more humic fraction than other organic fractions in different percent, so this fraction is not the main for cause for UF membrane fouling. The fouling of colloids was tested before and after adding calcium. There is a severe fouling after adding Ca2+ to effluent colloids.

  9. Effect of two abrasive systems on resin bonding to laboratory-processed indirect resin composite restorations.

    Science.gov (United States)

    Bouschlicher, M R; Cobb, D S; Vargas, M A

    1999-01-01

    This study compared two methods of surface roughening or preparation, with or without the use of proprietary surface wetting agents, to evaluate their effect on resin cement adhesion to the following laboratory-processed, indirect restorations: Artglass (AG), belleGlass HP (BG), Concept (C), and Targis (T). Methods of surface roughening or preparation included microetching with aluminum oxide (AO): 50 microns at 34 psi and silanized silica coating, CoJet-Sand (CJ): 30 microns at 34 psi. Artglass and Concept were tested with and without the use of their respective surface wetting agents: Artglass Liquid (AGL) and Special Bond II (SB). One hundred twenty specimens, each consisting of a pair of cylinders (7.0 x 3 mm and 4.3 x 3 mm) were fabricated. The larger cylinder or base was embedded in self-curing resin in a phenolic ring, and bonding surfaces were finished with 320-grit silicon carbide paper. Specimen pairs for each restorative material were randomly assigned to treatment groups (n = 10) and received the following surface treatments prior to cementation: group 1 (AG/AO/+AGL), group 2 (AG/AO/-AGL), group 3 (AG/CJ/+AGL), group 4 (AG/CJ/-AGL), group 5 (BG/AO), group 6 (BG/CJ), group 7 (C/AO/+SB), group 8 (C/AO/-SB), group 9 (C/CJ/+SB), group 10 (C/CJ/-SB), group 11 (T/AO), and group 12 (T/CJ). Specimen pairs were cemented with a dual-cure resin cement (Dual) and a standardized force of 1 MPa. Specimens were light-cured 40 seconds per side (80 s total), then thermocycled 300 times at between 5 degrees and 55 degrees C. Shear bond strengths (MPa) were determined using a Zwick Materials Testing Machine at a crosshead speed of 5 mm per minute. One-way analysis of variance (ANOVA) and Duncan's multiple range test (alpha = 0.05) by restoration type indicated no significant differences in shear bond strength between BG group 5 (29.8 +/- 5.8), BG group 6 (28.3 +/- 4.3), T group 11 (29.3 +/- 4.9), and T group 12 (29.0 +/- 4.4). Shear bond strength in AG group 3 (35.9 +/- 3

  10. A new resin system for the impregnation and bonding of large magnet coils

    CERN Document Server

    Evans, D

    1998-01-01

    ATLAS is an instrument which forms part of the Large Hadron Collider, a high energy physics experiment which is under construction at CERN, Geneva, Switzerland. The properties of the candidate resin systems developed for the impregnation of the Atlas End Cap Toroid magnets are presented. The resin systems contain a blend of two resins; a low viscosity Bisphenol F resin, with a long chain aliphatic epoxide resin. An aromatic amine curing agent was used. It was found that increased additions of the long chain aliphatic epoxide resin resulted in longer useable life, lower glass transition temperature, lower modulus, higher toughness and higher bond strength at 4 K. (4 refs).

  11. The effects of ionizing radiation on Reillex trademark HPQ, a new macroporous polyvinylpyridine resin, and on four conventional polystyrene anion exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F.

    1990-11-01

    This study compares the effects of ionizing radiation on Reillex{trademark} HPQ, a recently available macroporous copolymer of 1-methyl-4-vinylpyridine/divinylbenzene, and on four conventional strong-base polystyrene anion exchange resins. The polystyrene resins investigated included one gel type, Dowex{trademark} 1 {times} 4, and three macroporous resins: Dow{trademark} MSA-1, Amberlite{trademark} IRA-900, and Lewatit{trademark} MP-500-FK. Each resin, in 7 M nitric acid, was subjected to seven different levels of {sup 60}Co gamma radiation ranging from 100 to 1000 megarads. Irradiated resins were measured for changes in dry weight, wet volume, chloride and Pu(IV) exchange capacities, and thermal stability. In separate experiments, each resin was subjected to approximately 340 megarads of in situ alpha particles from sorbed plutonium. Resin damage from alpha particles was less than half that caused by gamma rays, which may be a consequence of different production rates of radiolytic nitrite and nitro radicals in the two systems. Reillex{trademark} HPQ resin provided the greatest radiation stability, whereas Lewatit{trademark} MP-500-FK was the least stable of the resins tested. Thermogravimetric analyses of dry, nitrate-form resin revealed that dry Reillex{trademark} HPQ resin offered the best thermal stability for absorbed gamma doses to 370 megarads, but the worst thermal stability after exposures of 550 megarads or more. 25 refs., 11 figs., 13 tabs.

  12. Color Stability of IDM Composite Resin

    Directory of Open Access Journals (Sweden)

    Ghavam M

    2000-06-01

    Full Text Available Discoloration of composite resins is considered to be a major factor in esthetic restoration"nfailures. The aim of this study was to evaluate color stability of IDM composite (both light and self cure"nsamples namely IL and IS, and to compare it with a self-cure composite (Degufill named DS and a light"ncure ormocer composite (Definite, called DL in the Report. 60 disk shaped samples of each composite"nwere prepared, according to ISO-7491. The samples were divided into 3 groups and aged as follows:"nA- (Control 7 days in dark 37°c chamber"nB- Foil covered and kept in 100% humidity, and 37°c in xenotest chamber for 24 hours, then transferred"nto a dark 37°c chamber for 6 more days."nC- Kept in 37°c, 100% humidity under the emission of xiiion lamp of xenotest chamber for 24 hours,"nand then transferred to 37°c dark chamber for 6 more days"nThe lightness and chromaticity values of samples were measured both before and after aging using a"nspectrophotometer (Data Flash. The total color changes as well as changes in lightness and chromaticity"nvalues were measured in the CIE L * a * b * scale, and analyzed. Color change was recorded to be"nsignificant in all samples after aging. The maximum change belonged to IL, which was significantly"ndifferent from DL and DS. It seems, in order to have a durable esthetic restoration using IDM, more"nscientific and professional consideration is needed in the production process.

  13. Shear bond strength evaluation of resin composite to resin-modified glass-ionomer cement using three different resin adhesives vs. glass-ionomer based adhesive

    Directory of Open Access Journals (Sweden)

    Mostafa Sadeghi

    2015-12-01

    Full Text Available Background: The clinical success of sandwich technique depends on the strength of resin-modified glass ionomer cement (RMGIC bonding to both dentin and resin composite. Therefore, the shear bond strength (SBS of resin composite bonded to RMGIC utilizing different resin adhesives versus a GIC-based adhesive was compared. Materials and methods: In this in vitro study, 84 holes (5×2 mm were prepared in acrylic blocks, randomly divided into seven groups (n=12 and filled with RMGIC (Light-Cured Universal Restorative, GC. In the Group I; no adhesive was applied on the RMGIC. In the Group II, non-etched and Group III was etched with phosphoric acid. In groups II and III, after rinsing, etch-and-rinse adhesive (OptiBond Solo Plus; in the Group IV; a two-step self-etch adhesive (OptiBond XTR and in Group V; a one-step self-etch (OptiBond All-in-One were applied on the cement surfaces. Group VI; a GIC-based adhesive (Fuji Bond LC was painted over the cement surface and cured. Group VII; the GIC-based adhesive was brushed over RMGIC followed by the placement of resin composite and co-cured. Afterward; resin composite (Point 4 cylinders were placed on the treated cement surfaces. The specimens were placed in 100% humidity at 37 ± 1°C and thermo cycled. The shear bond test was performed at a cross-head speed of 1 mm/min and calculated in MPa; the specimens were examined to determine mode of failure. The results were analyzed using one-way ANOVA and Tukey test. Results: The maximum (24.62±3.70 MPa and minimum (18.15±3.38 MPa SBS mean values were recorded for OptiBond XTR adhesive and the control group, respectively. The pairwise comparisons showed no significant differences between the groups that bonded with different adhesives. The adhesive failure was the most common failure mode observed. Conclusion: This study suggests that GIC-based adhesive could be applied over RMGIC as co-cure technique for sandwich restorations in lieu of employing the resin

  14. Uranium removal from contaminated groundwater by synthetic resins.

    Science.gov (United States)

    Phillips, D H; Gu, B; Watson, D B; Parmele, C S

    2008-01-01

    Synthetic resins are shown to be effective in removing uranium from contaminated groundwater. Batch and field column tests showed that strong-base anion-exchange resins were more effective in removing uranium from both near-neutral-pH (6.5)- and high-pH (8)-low-nitrate-containing groundwaters, than metal-chelating resins, which removed more uranium from acidic-pH (5)-high-nitrate-containing groundwater from the Oak Ridge Reservation (ORR) Y-12 S-3 Ponds area in Tennessee, USA. Dowex 1-X8 and Purolite A-520E anion-exchange resins removed more uranium from high-pH (8)-low-nitrate-containing synthetic groundwater in batch tests than metal-chelating resins. The Dowex 21K anion-exchange resin achieved a cumulative loading capacity of 49.8 mg g(-1) before breakthrough in a field column test using near-neutral-pH (6.5)-low-nitrate-containing groundwater. However, in an acidic-pH (5)-high-nitrate-containing groundwater, metal-chelating resins Diphonix and Chelex-100 removed more uranium than anion-exchange resins. In 15 m L of acidic-pH (5)-high-nitrate-containing groundwater spiked with 20 mg L(-1) uranium, the uranium concentrations ranged from 0.95 mg L(-1) at 1-h equilibrium to 0.08 mg L(-1) at 24-h equilibrium for Diphonix and 0.17 mg L(-1) at 1-h equilibrium to 0.03 mg L(-1) at 24-h equilibrium for Chelex-100. Chelex-100 removed more uranium in the first 10 min in the 100mL of acidic-(pH 5)-high-nitrate-containing groundwater ( approximately 5 mg L(-1) uranium); however, after 10 min, Diphonix equaled or out-performed Chelex-100. This study presents an improved understanding of the selectivity and sorption kenetics of a range of ion-exchange resins that remove uranium from both low- and high-nitrate-containing groundwaters with varying pHs.

  15. Uranium Removal from Contaminated Groundwater by Synthetic Resins

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Debra H. [Queen' s University, Belfast; Gu, Baohua [ORNL; Watson, David B [ORNL; Parmele, C. S. [Science Applications International Corporation (SAIC), Oak Ridge, TN

    2008-01-01

    Synthetic resins are shown to be effective in removing uranium from contaminated groundwater. Batch and field column tests showed that strong-base anion-exchange resins were more effective in removing uranium from both near-neutral-pH (6.5)- and high-pH (8)-low-nitrate-containing ground waters, than metal-chelating resins, which removed more uranium from acidic-pH (5)-high-nitrate-containing groundwater from the Oak Ridge Reservation (ORR) Y-12 S-3 Ponds area in Tennessee, USA. Dowex 1-X8 and Purolite A-520E anion-exchange resins removed more uranium from high-pH (8)-low-nitrate-containing synthetic groundwater in batch tests than metal-chelating resins. The Dowex{trademark} 21K anion-exchange resin achieved a cumulative loading capacity of 49.8 mg g{sup -1} before breakthrough in a field column test using near-neutral-pH (6.5)-low-nitrate-containing groundwater. However, in an acidic-pH (5)-high-nitrate-containing groundwater, metal-chelating resins Diphonix and Chelex-100 removed more uranium than anion-exchange resins. In 15 mL of acidic-pH (5)-high-nitrate-containing groundwater spiked with 20 mg L{sup -1} uranium, the uranium concentrations ranged from 0.95 mg L{sup -1} at 1-h equilibrium to 0.08 mg L{sup -1} at 24-h equilibrium for Diphonix and 0.17 mg L{sup -1} at 1-h equilibrium to 0.03 mg L{sup -1} at 24-h equilibrium for Chelex-100. Chelex-100 removed more uranium in the first 10 min in the 100 mL of acidic-(pH 5)-high-nitrate-containing groundwater (5 mg L{sup -1} uranium); however, after 10 min, Diphonix equaled or out-performed Chelex-100. This study presents an improved understanding of the selectivity and sorption kinetics of a range of ion-exchange resins that remove uranium from both low- and high-nitrate-containing groundwaters with varying pHs.

  16. High elastic modulus nanopowder reinforced resin composites for dental applications

    Science.gov (United States)

    Wang, Yijun

    2007-12-01

    Dental restorations account for more than $3 billion dollars a year on the market. Among them, all-ceramic dental crowns draw more and more attention and their popularity has risen because of their superior aesthetics and biocompatibility. However, their relatively high failure rate and labor-intensive fabrication procedure still limit their application. In this thesis, a new family of high elastic modulus nanopowder reinforced resin composites and their mechanical properties are studied. Materials with higher elastic modulus, such as alumina and diamond, are used to replace the routine filler material, silica, in dental resin composites to achieve the desired properties. This class of composites is developed to serve (1) as a high stiffness support to all-ceramic crowns and (2) as a means of joining independently fabricated crown core and veneer layers. Most of the work focuses on nano-sized Al2O3 (average particle size 47 nm) reinforcement in a polymeric matrix with 50:50 Bisphenol A glycidyl methacrylate (Bis-GMA): triethylene glycol dimethacrylate (TEGDMA) monomers. Surfactants, silanizing agents and primers are examined to obtain higher filler levels and enhance the bonding between filler and matrix. Silane agents work best. The elastic modulus of a 57.5 vol% alumina/resin composite is 31.5 GPa compared to current commercial resin composites with elastic modulus alumina, diamond/resin composites are studied. An elastic modulus of about 45 GPa is obtained for a 57 vol% diamond/resin composite. Our results indicate that with a generally monodispersed nano-sized high modulus filler, relatively high elastic modulus resin-based composite cements are possible. Time-dependent behavior of our resin composites is also investigated. This is valuable for understanding the behavior of our material and possible fatigue testing in the future. Our results indicate that with effective coupling agents and higher filler loading, viscous flow can be greatly decreased due to the

  17. Flexural properties of experimental nanofiber reinforced composite are affected by resin composition and nanofiber/resin ratio.

    Science.gov (United States)

    Vidotti, Hugo A; Manso, Adriana P; Leung, Victor; do Valle, Accácio L; Ko, Frank; Carvalho, Ricardo M

    2015-09-01

    To evaluate the influence of different resin blends concentrations and nanofibers mass ratio on flexural properties of experimental Poliacrylonitrile (PAN) nanofibers reinforced composites. Poliacrylonitrile (PAN) nanofibers mats were produced by electrospinning and characterized by tensile testing and scanning electron microscopy (SEM). Experimental resin-fiber composite beams were manufactured by infiltrating PAN nanofiber mats with varied concentrations of BisGMA-TEGDMA resin blends (BisGMA/TEGDMA: 30/70, 50/50 and 70/30weight%). The mass ratio of fiber to resin varied from 0% to 8%. Beams were cured and stored in water at 37°C. Flexural strength (FS), flexural modulus (FM) and work of fracture (WF) were evaluated by three-point bending test after 24h storage. The tensile properties of the PAN nanofibers indicated an anisotropic behavior being always higher when tested in a direction perpendicular to the rotation of the collector drum. Except for WF, the other flexural properties (FS and FM) were always higher as the ratio of BisGMA to TEGDMA increased in the neat resin beams. The addition of different ratios of PAN fibers did not affect FS and FM of the composite beams as compared to neat resin beams (p>0.05). However, the addition of fibers significantly increased the WF of the composite beams, and this was more evident for the blends with higher TEGDMA ratios (pnanofibers into resin blends did not negatively affect the properties of the composite and resulted in an increase in toughness that is a desirable property for a candidate material for prosthodontics application. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Fracture Resistance of Endodontically Treated Teeth Restored with Biodentine, Resin Modified GIC and Hybrid Composite Resin as a Core Material.

    Science.gov (United States)

    Subash, Dayalan; Shoba, Krishnamma; Aman, Shibu; Bharkavi, Srinivasan Kumar Indu; Nimmi, Vijayan; Abhilash, Radhakrishnan

    2017-09-01

    The restoration of a severely damaged tooth usually needs a post and core as a part of treatment procedure to provide a corono - radicular stabilization. Biodentine is a class of dental material which possess high mechanical properties with excellent biocompatibility and bioactive behaviour. The sealing ability coupled with optimum physical properties could make Biodentine an excellent option as a core material. The aim of the study was to determine the fracture resistance of Biodentine as a core material in comparison with resin modified glass ionomer and composite resin. Freshly extracted 30 human permanent maxillary central incisors were selected. After endodontic treatment followed by post space preparation and luting of Glass fibre post (Reforpost, Angelus), the samples were divided in to three groups based on the type of core material. The core build-up used in Group I was Biodentine (Septodont, France), Group II was Resin-Modified Glass Ionomer Cement (GC, Japan) and Group III was Hybrid Composite Resin (TeEconom plus, Ivoclar vivadent). The specimens were subjected to fracture toughness using Universal testing machine (1474, Zwick/Roell, Germany) and results were compared using One-way analysis of variance with Tukey's Post hoc test. The results showed that there was significant difference between groups in terms of fracture load. Also, composite resin exhibited highest mean fracture load (1039.9 N), whereas teeth restored with Biodentine demonstrated the lowest mean fracture load (176.66 N). Resin modified glass ionomer exhibited intermediate fracture load (612.07 N). The primary mode of failure in Group I and Group II was favourable (100%) while unfavourable fracture was seen in Group III (30%). Biodentine, does not satisfy the requirements to be used as an ideal core material. The uses of RMGIC's as a core build-up material should be limited to non-stress bearing areas. Composite resin is still the best core build-up material owing to its high fracture

  19. Bonding between CAD/CAM resin and resin composite cements dependent on bonding agents: three different in vitro test methods.

    Science.gov (United States)

    Gilbert, Simona; Keul, Christine; Roos, Malgorzata; Edelhoff, Daniel; Stawarczyk, Bogna

    2016-03-01

    The aim of this study was to assess the bonding properties between CAD/CAM resin and three resin composite cements combined with different bonding agents using three test methods. Four hundred twenty CAD/CAM resin substrates were fabricated and divided into three test methods (shear bond strength (SBS, n = 180), tensile bond strength (TBS, n = 180) and work of adhesion (WA, n = 60)), further into four pretreatment methods (VP connect (VP), visio.link (VL), Clearfil Ceramic Primer (CP) and no pretreatment (CG)) and three cements (RelyX ARC, Variolink II and Clearfil SA Cement). Each subgroup contained 15 specimens. SBS and TBS were measured after 24 h H2O/37 °C + 5000 thermal-cycles (5/55 °C) and failure types were assessed. WA was determined for pretreated CAD/CAM resin and non-polymerized resin composite cements. Data were analysed with Mann-Whitney U, Kruskal-Wallis H, Chi(2) and Spearman's Rho tests. Within SBS and TBS tests, CGs and groups pretreated with CP (regardless of resin composite cements), and VP pretreated with Clearfil SA Cement showed no bond. However, CG combined with RelyX ARC showed a TBS of 5.6 ± 1.3 MPa. In general, highest bond strength was observed for groups treated with VL. CG and groups pretreated using VL showed lower WA than the groups treated with VP or CP. Measured TBS values were higher than SBS ones. In general, SBS and TBS showed similar trends for the ranges of the values for the groups. WA results were not comparable with SBS/TBS results and admitted, therefore, no conclusions on it. For a clinical use of XHIP-CAD/CAM resin, the bond surface should be additionally pretreated with visio.link as bonding agent.

  20. Use of dental adhesives as modeler liquid of resin composites.

    Science.gov (United States)

    Münchow, Eliseu Aldrighi; Sedrez-Porto, José Augusto; Piva, Evandro; Pereira-Cenci, Tatiana; Cenci, Maximiliano Sergio

    2016-04-01

    Resin adhesives (RA) have been applied between resin composite (RC) increments, but there is no consensus on the impact of this technique on the properties of the final restoration. This study evaluated the effect of the presence of RA between RC layers on physical properties, translucency and long-term color stability of the restorative material. Scotchbond™ Multi-Purpose (bond, 3M ESPE) and Adper™ Single Bond 2 (3M ESPE) were used as RA, and Filtek™ Z350 (3M ESPE) as RC. Specimens containing RA were prepared by applying 3 layers of the adhesive between 4 increments of RC; adhesive-free specimens were also used (control). Tests of water sorption and solubility, mechanical performance (microtensile cohesive strength, flexural strength, and flexural modulus, after immediate and long-term water storage), and translucency and color stability (after immediate and 1, 7, 90, and 180 days of water or wine storage) were performed. Scanning electron microscopy (SEM) images were also taken from the fractured specimens (flexural strength test). Data were analyzed using ANOVA and Tukey test (padhesive resin (SBMP). This study is the first to show positive results from the use of resin adhesives as modeler liquid of resin composite, which is common in clinical practice. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. Adhesive primers for bonding cobalt-chromium alloy to resin.

    Science.gov (United States)

    Yoshida, K; Kamada, K; Atsuta, M

    1999-06-01

    This study evaluated the effect of five adhesive primers on the shear bond strength of a self-curing resin to cobalt-chromium (Co-Cr) alloy. The adhesive primers Acryl Bond (AB, Shofu), Cesead Opaque Primer (COP, Kuraray), Metacolor Opaque Bonding Liner (MOBL, Sun-Medical), Metal PrimerII (MPII, GC) and MR. Bond (MRB, Tokuyama) were used. A brass ring which was placed over the casting alloy disk surface non-primed or primed with each primer was filled with the self-curing MMA-PMMA resin. The specimens were stored in water at 37 degrees C for 24 h and then immersed alternately in water baths at 4 C and 60 degrees C for 1 min each for up to 50000 thermal cycles before shear mode testing at a crosshead speed of 0.5 mm/min. All of the primers examined, except MOBL, improved the shear bond strength between the resin and Co-Cr alloy compared with nonprimed specimens prior to thermal cycling. Regardless of which primer was used, the shear bond strength significantly differed between thermal cycles 0 and 50000. However, after 50000 thermal cycles, the bond strengths of resin to Co-Cr alloy primed with COP or MPII were significantly greater than those of specimens primed with AB, MOBL or MRB and non-primed controls. This study indicated that COP and MPII are effective primers to obtain higher bond strength between resin and Co-Cr alloy.

  2. Antimicrobial Assessment of Resins from Calophyllum Antillanum and Calophyllum Inophyllum.

    Science.gov (United States)

    Cuesta-Rubio, Osmany; Oubada, Ahmad; Bello, Adonis; Maes, Louis; Cos, Paul; Monzote, Lianet

    2015-12-01

    The Calophyllum genus is well-known for its antimicrobial and cytotoxic activities, and therefore, we analyzed these biological activities for resins of Calophyllum antillanum and Calophyllum inophyllum growing in Cuba. C. antillanum resins showed a potent activity against Plasmodium falciparum (IC50  = 0.3 ± 0.1 µg/mL), while its cytotoxicity against MRC-5 cells was much lower (IC50  = 21.6 ± 1.1 µg/mL). In contrary, the resin of C. inophyllum showed an unspecific activity. The presence of apetalic acid, isoapetalic acid, calolongic acid, pinetoric acid I, pinetoric acid II, isocalolongic acid, pinetoric acid III, and isopinetoric acid III in C. antillanum resins was also confirmed. These results demonstrated for the first time the potential activity of C. antillanum resins against P. falciparum. Copyright © 2015 John Wiley & Sons, Ltd.

  3. Surface Hardness of Resin Cement Polymerized under Different Ceramic Materials

    Directory of Open Access Journals (Sweden)

    Pimmada Kesrak

    2012-01-01

    Full Text Available Objectives. To evaluate the surface hardness of two light-cured resin cements polymerized under different ceramic discs. Methods. 40 experimental groups of 2 light-cured resin cement specimens (Variolink Veneer and NX3 were prepared and polymerized under 5 different ceramic discs (IPS e.max Press HT, LT, MO, HO, and Cercon of 4 thicknesses (0.5, 1.0, 1.5, and 2.0 mm, Those directly activated of both resin cements were used as control. After light activation and 37∘C storage in an incubator, Knoop hardness measurements were obtained at the bottom. The data were analyzed with three-way ANOVA, t-test, and one-way ANOVA. Results. The KHN of NX3 was of significantly higher than that of Variolink Veneer (<0.05. The KHN of resin cement polymerized under different ceramic types and thicknesses was significant difference (<0.05. Conclusion. Resin cements polymerized under different ceramic materials and thicknesses showed statistically significant differences in KHN.

  4. Persistent photosensitivity after allergic contact dermatitis to epoxy resin.

    Science.gov (United States)

    Kwok, Tiffany; Rosen, Cheryl F; Storrs, Frances J; Lobel, Edmund; DeKoven, Joel G

    2013-01-01

    Persistent photosensitivity after allergic contact dermatitis (ACD) to epoxy resin has rarely been described. The aim of this study was to create awareness that ACD to epoxy may be a trigger for persistent photosensitivity. We present a series of 5 patients who developed ACD to epoxy resin and later a photodistributed eczematous eruption when exposed to sunlight, with a documented decrease in minimal erythema dose to UVA and UVB. The age of patients ranged from 34 to 71 years, and there were 3 men and 2 women. Each patient had occupational exposure to epoxy. Symptoms of epoxy ACD preceded photosensitivity by 5 months to 12 years in 3 cases and occurred simultaneously in 2 cases. Patch testing to epoxy resin was positive in all patients. Phototesting revealed a decreased minimal erythema dose to UVA and UVB in each of the 3 patients who were phototested. Photopatch testing was positive for epoxy resin in 1 of the 2 patients tested. All patients remained photosensitive for at least 2 years after diagnosis, with only 1 case of photosensitivity resolving with extended avoidance of epoxy. There is an association between ACD to epoxy resin and development of persistent photosensitivity. Possible mechanisms to explain the relationship between the 2 phenomena are discussed.

  5. Effect of Sandblasting on Shear Bond Strength Composite Resin Veneer

    Directory of Open Access Journals (Sweden)

    Octarina Octarina

    2013-07-01

    Full Text Available Attachment between restoration and enamel surface in indirect resin composite veneer restoration (IRCV is obtained using multi-step (MS resin cement. Recently, a one step self-adhesive dual-cured resin cement (SADRC was introduced. Objective: To determine the effect of sandblasting on shear bond strength (SBS of IRCV to enamel using MS resin cement and SADRC. Methods: Forty specimens of buccal surface of enamel human were light-cured in Solidilite chamber and were divided into two groups: IRCV without sandblasting (n=20 and with sandblasting for 10 seconds (n=20 and then bonded to enamel using MS (n=10 and SADRC (n=10, respectively. After 24h SBS of specimens were tested using a Universal Testing Machine. Data were analyzed statistically by one-way ANOVA. Results: The average SBS value of IRCV without SB and bonded with MS was 18.95+7.80MPa and MS with SB was 19.30+ SB (4.85+2.12MPa and SADRC with SB (9.57+3.45MPa(p<0.05. Conclusion: increased SBS VIRK to enamel using MS resin cement than SADRC.  

  6. Adhesives Based on Furan Resin for Structural Laminated Timber

    Directory of Open Access Journals (Sweden)

    Octavia ZELENIUC

    2013-06-01

    Full Text Available In wood laminated products manufacturing thephenol-based adhesives are especially used. Recentlyother adhesives such as polyurethanes were promotedon the market for structural applications withremarkable properties. Structural adhesives have tofulfil the requirements according to their uses, underwet or dry conditions as adhesive type I and type IIrespectively. Criteria for evaluating structuraladhesives, includes delamination resistance, shearstrength of bond and percent of wood failure. Thisstudy has the objective to evaluate the bondingperformance of furan based resin and its suitability forstructural purposes. There are some investigationsabout the possibility of incorporating the furan resin intowood adhesive formulations but their industrialexploitation is still modest. Three experimentaladhesive compositions based on furan and ureaformaldehyderesins, were used to cold-glue beechand spruce lamellas to form a structural timber likeglued laminated timber. Adhesive formulations includedmixed furan resin with furfuryl alcohol (FC2 and twomodified furan resins with urea-formaldehyde resin(UR/FC2 and UR/FC3 at 50% UR. Bond shearstrength by longitudinal tensile and resistance todelamination were performed according to SR EN302:2004. The best performance was obtained withadhesive FC2 which showed shear strength above thevalues indicated for structural adhesives in EN301:2004. FC2 adhesive performed significantly betterin delamination tests too, both in dry and wetconditions, compared to the other two adhesives,showing promise for its use in load-bearing timberstructures.

  7. Terpenoid composition and class of Tertiary resins from India

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Suryendu; Mallick, Monalisa; Mathews, Runcie Paul [Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India); Bertram, Norbert [LTA-Labor fuer Toxikologie und Analytik, Friedrichshoeher Str. 28, D-53639 Koenigswinter (Germany); Greenwood, Paul F. [John De Laeter Mass Spectrometry and WA Biogeochemitry Centres (M090), The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009 (Australia); WA - Organic and Isotope Geochemistry Centre, Curtin University of Technology, Kent St., Bentley 6102 (Australia)

    2009-10-01

    The terpenoid composition and class of Tertiary resins preserved within lignites of Cambay, Kutch and Cauvery Basins of India have been characterized using Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS) and Fourier Transform Infrared (FTIR) Spectroscopy. Major pyrolysis products include cadalene-based C{sub 15}-bicyclic sesquiterpenoids with some C{sub 30} and C{sub 31} bicadinanes and bicadinenes typical of Class II or dammar resin. The occurrence of these terpenoids in Early Eocene sediments may extend the first appearance of Dipterocarpaceae angiosperms, the predominant source of this resin class, back to the Early Eocene epoch in India. The same terpenoid biomarkers have been detected in many SE Asian oils reflecting a close source relationship with these resins. Strong CH{sub 3} (1377 cm{sup -} {sup 1}) and other CH{sub x} (3000-2800 and 1460-1450 cm{sup -} {sup 1}) aliphatic absorptions of much larger intensity than the aromatic C = C (1560-1650 cm{sup -} {sup 1}) absorption were detected in the Indian resins by FTIR Spectroscopy, confirming the quantitative significance of the terpenoid pyrolysates. (author)

  8. Acute toxicity and laxative activity of Aloe ferox resin

    Directory of Open Access Journals (Sweden)

    Vanessa R. L. Celestino

    2013-02-01

    Full Text Available Aloe ferox Mill., Xanthorrhoeaceae, resin is the solid residue obtained by evaporating the latex that drains from the leaves transversally cut. Aloe ferox has been used in folk medicine as anti-inflammatory, immunostimulant, anti-bacterial, anti-fungal, antitumor, laxative and to heal wounds and burns. The effects of the oral administration of A. ferox resin (10, 25, 50, 100 and 200 mg/kg were evaluated on intestinal transit in mice and its acute toxicity (5.0 g/kg in Wistar rats. The hydroxyanthracene derivatives present in the resin were expressed as aloin, identified by thin layer chromatography and quantified by spectrophotometry. The aloin (Rf 0.35 was identified and the percentage of hydroxyanthracene derivates expressed as aloin was 33.5%. A. ferox resin extract (50, 100 and 200 mg/kg increased the gastrointestinal motility at a 30 min interval at 93.5, 91.8 and 93.8%, respectively, when compared to control group (46.5%. A single oral dose of the A. ferox resin extract did not induce signs of toxicity or death. Thus, the results demonstrate that A. ferox has laxative activity and that it is nontoxic, since LD50 could not be estimated and it is possibly higher than 5.0 g/kg.

  9. Acute toxicity and laxative activity of Aloe ferox resin

    Directory of Open Access Journals (Sweden)

    Vanessa R. L. Celestino

    2013-04-01

    Full Text Available Aloe ferox Mill., Xanthorrhoeaceae, resin is the solid residue obtained by evaporating the latex that drains from the leaves transversally cut. Aloe ferox has been used in folk medicine as anti-inflammatory, immunostimulant, anti-bacterial, anti-fungal, antitumor, laxative and to heal wounds and burns. The effects of the oral administration of A. ferox resin (10, 25, 50, 100 and 200 mg/kg were evaluated on intestinal transit in mice and its acute toxicity (5.0 g/kg in Wistar rats. The hydroxyanthracene derivatives present in the resin were expressed as aloin, identified by thin layer chromatography and quantified by spectrophotometry. The aloin (Rf 0.35 was identified and the percentage of hydroxyanthracene derivates expressed as aloin was 33.5%. A. ferox resin extract (50, 100 and 200 mg/kg increased the gastrointestinal motility at a 30 min interval at 93.5, 91.8 and 93.8%, respectively, when compared to control group (46.5%. A single oral dose of the A. ferox resin extract did not induce signs of toxicity or death. Thus, the results demonstrate that A. ferox has laxative activity and that it is nontoxic, since LD50 could not be estimated and it is possibly higher than 5.0 g/kg.

  10. Monitoring the Cure State of Thermosetting Resins by Ultrasound

    Directory of Open Access Journals (Sweden)

    Alfonso Maffezzoli

    2013-09-01

    Full Text Available The propagation of low intensity ultrasound in a curing resin, acting as a high frequency oscillatory excitation, has been recently proposed as an ultrasonic dynamic mechanical analysis (UDMA for cure monitoring. The technique measures sound velocity and attenuation, which are very sensitive to changes in the viscoelastic characteristics of the curing resin, since the velocity is related to the resin storage modulus and density, while the attenuation is related to the energy dissipation and scattering in the curing resin. The paper reviews the results obtained by the authors’ research group in the last decade by means of in-house made ultrasonic set-ups for both contact and air-coupled ultrasonic experiments. The basics of the ultrasonic wave propagation in polymers and examples of measurements of the time-evolution of ultrasonic longitudinal modulus and chemical conversion of different thermosetting resins are presented. The effect of temperature on the cure kinetics, the comparison with rheological, low frequency dynamic mechanical and calorimetric results, and the correlation between ultrasonic modulus and crosslinking density will be also discussed. The paper highlights the reliability of ultrasonic wave propagation for monitoring the physical changes taking place during curing and the potential for online monitoring during polymer and polymer matrix composite processing.

  11. Modification of (DGEBA epoxy resin with maleated depolymerised natural rubber

    Directory of Open Access Journals (Sweden)

    2008-04-01

    Full Text Available In this work, diglycidyl ether of bisphenol A (DEGBA type epoxy resin has been modified with maleated depolymerised natural rubber (MDPR. MDPR was prepared by grafting maleic anhydride onto depolymerised natural rubber. MDPR has been characterized by Fourier transform infrared (FT-IR spectroscopy and nuclear magnetic resonance spectroscopy. MDPR was blended with epoxy resin at three different ratios (97/3, 98/2 and 99/1, by keeping the epoxy resin component as the major phase and maleated depolymerised natural rubber component as the minor phase. The reaction between the two blend components took place between the acid/anhydride group in the MDPR and the epoxide group of the epoxy resin. The proposed reaction schemes were supported by the FT-IR spectrum of the uncured Epoxy/MDPR blends. The neat epoxy resin and Epoxy/MDPR blends were cured by methylene dianiline (DDM at 100°C for three hours. Thermal, morphological and mechanical properties of the neat epoxy and the blends were investigated. Free volume studies of the cured, neat epoxy and Epoxy/MDPR blends were correlated with the morphological and mechanical properties of the same systems using Positron Annihilation Lifetime Studies.

  12. The elastic moduli across various types of resin/dentin interfaces.

    Science.gov (United States)

    Pongprueksa, Pong; Kuphasuk, Watcharaporn; Senawongse, Pisol

    2008-08-01

    The purpose of this study was to evaluate the elastic moduli of an unfilled adhesive resin (Adper Single Bond) and a filled adhesive resin (Adper Single Bond 2) used with and without a low-viscosity resin (LVR) (Filtek Flow) as an elastic cavity wall in class V composite restorations, restored with a hybrid resin composite (Z250). Buccal class V cavities were prepared on extracted premolars and lined with (1) the unfilled adhesive resin, (2) the filled adhesive resin, (3) the unfilled adhesive resin and the flowable composite, and (4) the filled adhesive resin and the flowable composite. All cavities were restored with the hybrid resin composite. The specimens were cut bucco-lingually, embedded in epoxy resin and polished. The polished specimens were evaluated for the elastic modulus with nano-indentation test at the layer of dentin, hybrid layer, adhesive resin, low-viscosity resin and resin composite. The elastic moduli were 25,111 MPa for dentin, 12,243 MPa for hybrid layer of Adper Single Bond, 11,765 MPa for hybrid layer of Adper Single Bond 2, 7595 MPa for Adper Single Bond, 8430 MPa for Adper Single Bond 2, 13,543 MPa for Filtek Flow and 24,494 MPa for Filtek Z250 resin composite. The statistical analysis demonstrated that the elastic moduli were significantly different among layers (p<0.05) except between hybrid layers of unfilled and filled adhesives (p=1.0). The application of filled adhesive did not increase the elastic modulus of hybrid layer when compared with the unfilled adhesive resin. The modulus of filled adhesive resin was significantly higher than that of unfilled adhesive resin.

  13. Effects of resin content and preparing conditions on the properties of polyphenylene sulfide resin/graphite composite for bipolar plate

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Li-gang; Li, Ai-ju; Yin, Qiang [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Shandong Key Laboratory of Engineering Ceramics, Shandong University, Jinan 250061 (China); Wang, Wei-qiang [School of Mechanical Engineering, Shandong University, Jinan 250061 (China); Lin, Heng; Zhao, Yi-bo [School of Material Science and Engineering, Shandong University, Jinan 250061 (China)

    2008-03-15

    In the paper, a kind of polyphenylene sulfide (PPS) resin/graphite (G) composite for bipolar plate was prepared by using the PPS resin as adhesive and simple hot pressing. The influences of the resin content, the molding temperature and holding time on the conductivity and the bending strength of the PPS/G composite bipolar plate were investigated firstly and then the optimum content and the preparing conditions of the composite were obtained. The experimental results show that the electrical conductivity decreases and the bending strength reveals a serrated variation with increase in PPS resin content; when the holding time is certain, the conductivity decreases and the bending strength increases with the molding temperature increasing. The experimental results further show that the effect of the holding time on the properties of the composite is different at different molding temperatures. The PPS/G composite with 20% PPS resin content has electrical conductivity of 118.9 S cm{sup -1} and bending strength of 52.4 MPa when it molded at 380 C for 30 min, and has electrical conductivity of 105 S cm{sup -1}, bending strength of 55.7 MPa when it molded at 390 C for 30 min. The properties of the composites can meet the requirements of United States Department of Energy (DOE). (author)

  14. Resin-composite blocks for dental CAD/CAM applications.

    Science.gov (United States)

    Ruse, N D; Sadoun, M J

    2014-12-01

    Advances in digital impression technology and manufacturing processes have led to a dramatic paradigm shift in dentistry and to the widespread use of computer-aided design/computer-aided manufacturing (CAD/CAM) in the fabrication of indirect dental restorations. Research and development in materials suitable for CAD/CAM applications are currently the most active field in dental materials. Two classes of materials are used in the production of CAD/CAM restorations: glass-ceramics/ceramics and resin composites. While glass-ceramics/ceramics have overall superior mechanical and esthetic properties, resin-composite materials may offer significant advantages related to their machinability and intra-oral reparability. This review summarizes recent developments in resin-composite materials for CAD/CAM applications, focusing on both commercial and experimental materials. © International & American Associations for Dental Research.

  15. Resin glycosides from the aerial parts of Operculina turpethum.

    Science.gov (United States)

    Ding, Wenbing; Jiang, Zi-Hua; Wu, Ping; Xu, Liangxiong; Wei, Xiaoyi

    2012-09-01

    Three glycosidic acids, turpethic acids A-C, and two intact resin glycosides, turpethosides A and B, all having a common pentasaccharide moiety and 12-hydroxy fatty acid aglycones of different chain lengths, were obtained from the aerial parts of Operculina turpethum. Their structures were elucidated by spectroscopic analyses and chemical correlations. The aglycones were characterized as 12-hydroxypentadecanoic acid in two compounds, 12-hydroxyhexadecanoic acid in two other components, and 12-hydroxyheptadecanoic acid in the fifth compound, which were all confirmed by synthesis. The absolute configurations of these aglycones were all established as S by Mosher's method. These compounds represent the first examples of resin glycosides with a monohydroxylated 12-hydroxy fatty acid as an aglycone, and one compound is the first described resin glycoside having a hydroxylated C(17) fatty acid as its aglycone. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Thermodynamic description of peptide adsorption on mixed-mode resins.

    Science.gov (United States)

    Chilamkurthi, Sreekanth; Sevillano, David Méndez; Albers, Leonoor H G; Sahoo, Manas Ranjan; Verheijen, Peter J T; van der Wielen, Luuk A M; den Hollander, Jeroen L; Ottens, Marcel

    2014-05-09

    In this work the adsorption of tri-peptides on a mixed-mode resin was studied using isocratic pulse response experiments. Various salt concentration, temperature and pH combinations were used to measure retention times of several tri-peptides. The experiments were evaluated according to an extension of the stoichiometric displacement model and the steric mass action model of protein-ligand binding. The application of this model in the understanding of mixed mode adsorption process is discussed. A unique set of meaningful thermodynamic parameters was obtained for each resin-peptide-temperature and resin-peptide-pH combination. Finally it was shown that these thermodynamic parameters can be used in defining quantitative relationships within the framework of extra thermodynamic relationships. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Quantitative analysis of PMR-15 polyimide resin by HPLC

    Science.gov (United States)

    Roberts, Gary D.; Lauver, Richard W.

    1987-01-01

    The concentration of individual components and of total solids of 50 wt pct PMR-15 resin solutions was determined using reverse-phase HPLC to within + or - 8 percent accuracy. Acid impurities, the major source of impurities in 3,3', 4,4'-benzophenonetetracarboxylic acid (BTDE), were eliminated by recrystallizing the BTDE prior to esterification. Triester formation was not a problem because of the high rate of esterification of the anhydride relative to that of the carboxylic acid. Aging of PMR-15 resin solutions resulted in gradual formation of the mononadimide and bisnadimide of 4,4'-methylenedianiline, with the BTDE concentration remaining constant. Similar chemical reactions occurred at a reduced rate in dried films of PMR-15 resin.

  18. [Influence of time on shear strength using resin cements].

    Science.gov (United States)

    Weng, Wei-min; Zhang, Xiu-yin; Zhang, Fu-qiang

    2007-10-01

    To compare the shear bond strength of different composite resin cement systems at different time intervals. 48 healthy non-carious human molars were selected in the study. The samples were divided into two groups, 24 in each group. (1) RelyX unicem was used on bonding, (2) Variolink 2 was used on bonding. All specimens were stored in water at 37 degrees C for 2 hours, 24 hours and 1 week. 8 specimens in each group were stressed in shear until failure. Statistical analysis was performed with SPSS11.0 software package. Debonged surface was examined under light microscope. Shear bond strengths of two resin cements showed a significant increase as time went (Padhesive/dentin interfaces. Time can influence the shear bond strength using different composite resin cement systems. Supported by Shanghai Leading Academic Discipline Project (Grant No.T0202).

  19. Waterborne hyperbranched alkyd-acrylic resin obtained by miniemulsion polymerization

    Directory of Open Access Journals (Sweden)

    Edwin Murillo

    Full Text Available Abstract Four waterborne hyperbranched alkyd-acrylic resins (HBRAA were synthesized by miniemulsion polymerization from a hyperbranched alkyd resin (HBR, methyl methacrylate (MMA, butyl acrylate (BA and acrylic acid (AA, by using benzoyl peroxide (BPO and ammonium persulfate (AP as initiators. The reaction between HBR and acrylic monomers was evidenced by differential scanning calorimetric (DSC, nuclear magnetic resonance (NMR and gel permeation chromatography (GPC. The conversion percentage, glass transition temperature (Tg, content of acrylic polymer (determined by soxhlet extraction and molecular weight increased with the content of acrylic monomers used in the synthesis. The main structure formed during the synthesis was the HBRAA. The analysis by dynamic light scattering (DLS showed that the particle size distribution of HBRAA2, HBRAA3 and HBRAA4 resins were mainly monomodal. The film properties (gloss, flexibility, adhesion and drying time of the HBRAA were good.

  20. Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yudovin-Farber, Ira [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel); Beyth, Nurit; Weiss, Ervin I. [Hebrew University of Jerusalem, Department of Prosthodontics, Faculty of Dentistry (Israel); Domb, Abraham J., E-mail: avid@ekmd.huji.ac.i [Hebrew University of Jerusalem, Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Faculty of Medicine (Israel)

    2010-02-15

    Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

  1. Dental fiber-post resin base material: a review

    Science.gov (United States)

    Xu, Chun; Zhang, Fu-qiang

    2014-01-01

    Teeth that have short clinical crown, which are not alone enough to support the definitive restoration can be best treated using the post and core system. The advantages of fiber post over conventional metallic post materials have led to its wide acceptance. In addition to that the combination of aesthetic and mechanical benefits of fiber post has provided it with a rise in the field of dentistry. Also the results obtained from some clinical trials have encouraged the clinicians to use the fiber posts confidently. Fiber posts are manufactured from pre-stretched fibers impregnated within a resin matrix. The fibers could that be of carbon, glass/silica, and quartz, whereas Epoxy and bis-GMA are the most widely used resin bases. But recently studies are also found to be going on for polyimide as possible material for the fiber post resin base as a substitute for the conventional materials. PMID:24605208

  2. Viscoelastic behavior of multiwalled carbon nanotubes into phenolic resin

    Energy Technology Data Exchange (ETDEWEB)

    Botelho, Edson Cocchieri; Costa, Michelle Leali; Braga, Carlos Isidoro, E-mail: ebotelho@feg.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Guaratingueta, SP (Brazil). Dept. de Materiais e Tecnologia; Burkhart, Thomas [Institut fuer Verbundwerkstoffe GmbH, Kaiserslautern, (Germany); Lauke, Bernd [Leibniz-Institut fuer Polymerforschung, Dresden (Germany)

    2013-11-01

    Nanostructured polymer composites have opened up new perspectives for multi-functional materials. In particular, carbon nanotubes (CNTs) have the potential applications in order to improve mechanical and electrical performance in composites with aerospace application. This study focuses on the viscoelastic evaluation of phenolic resin reinforced carbon nanotubes, processed by using two techniques: aqueous-surfactant solution and three roll calender (TRC) process. According to our results a relative small amount of CNTs in a phenolic resin matrix is capable of enhancing the viscoelastic properties significantly and to modify the thermal stability. Also has been observed that when is used TRC process, the incorporation and distribution of CNT into phenolic resin is more effective when compared with aqueous solution dispersion process. (author)

  3. Chromatography of metal ions with a triazine chelating resin

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.N.

    1979-05-01

    The synthesis, characterization, and some analytical applications of a new triazine resin are described. Separation of group IB, IIB, VIB, and VIIB metal ions from group VIII metal ions is achieved by this PDT-4 resin. Calcium(II) and magnesium(II) are taken up at pH = 6, 0.1 M acetate and are eluted at pH = 6, 0.1 M sodium nitrate. Copper(II) is retained at pH = 6, 0.1 M acetate and pH = 1 hydrochloric acid and is eluted subsequently by 5 M perchloric acid. Molybdenum(VI) is sorbed selectively from 0.1 N sulfuric acid or hydrochloric acid and is eluted in a tight band by 0.1 N sodium hydroxide. Numerous rapid column chromatographic separations are reported using this new resin, including analysis of NBS standard samples.

  4. Dental fiber-post resin base material: a review.

    Science.gov (United States)

    Lamichhane, Aashwini; Xu, Chun; Zhang, Fu-Qiang

    2014-02-01

    Teeth that have short clinical crown, which are not alone enough to support the definitive restoration can be best treated using the post and core system. The advantages of fiber post over conventional metallic post materials have led to its wide acceptance. In addition to that the combination of aesthetic and mechanical benefits of fiber post has provided it with a rise in the field of dentistry. Also the results obtained from some clinical trials have encouraged the clinicians to use the fiber posts confidently. Fiber posts are manufactured from pre-stretched fibers impregnated within a resin matrix. The fibers could that be of carbon, glass/silica, and quartz, whereas Epoxy and bis-GMA are the most widely used resin bases. But recently studies are also found to be going on for polyimide as possible material for the fiber post resin base as a substitute for the conventional materials.

  5. Geopolymer resin materials, geopolymer materials, and materials produced thereby

    Science.gov (United States)

    Seo, Dong-Kyun; Medpelli, Dinesh; Ladd, Danielle; Mesgar, Milad

    2016-03-29

    A product formed from a first material including a geopolymer resin material, a geopolymer resin, or a combination thereof by contacting the first material with a fluid and removing at least some of the fluid to yield a product. The first material may be formed by heating and/or aging an initial geopolymer resin material to yield the first material before contacting the first material with the fluid. In some cases, contacting the first material with the fluid breaks up or disintegrates the first material (e.g., in response to contact with the fluid and in the absence of external mechanical stress), thereby forming particles having an external dimension in a range between 1 nm and 2 cm.

  6. Epoxy foams using multiple resins and curing agents

    Science.gov (United States)

    Russick, Edward M.; Rand, Peter B.

    2000-01-01

    An epoxy foam comprising a plurality of resins, a plurality of curing agents, at least one blowing agent, at least one surfactant and optionally at least one filler and the process for making. Preferred is an epoxy foam comprising two resins of different reactivities, two curing agents, a blowing agent, a surfactant, and a filler. According to the present invention, an epoxy foam is prepared with tailorable reactivity, exotherm, and pore size by a process of admixing a plurality of resins with a plurality of curing agents, a surfactant and blowing agent, whereby a foamable mixture is formed and heating said foamable mixture at a temperature greater than the boiling temperature of the blowing agent whereby said mixture is foamed and cured.

  7. Biobased Epoxy Resins from Deconstructed Native Softwood Lignin.

    Science.gov (United States)

    van de Pas, Daniel J; Torr, Kirk M

    2017-08-14

    The synthesis of novel epoxy resins from lignin hydrogenolysis products is reported. Native lignin in pine wood was depolymerized by mild hydrogenolysis to give an oil product that was reacted with epichlorohydrin to give epoxy prepolymers. These were blended with bisphenol A diglycidyl ether or glycerol diglycidyl ether and cured with diethylenetriamine or isophorone diamine. The key novelty of this work lies in using the inherent properties of the native lignin in preparing new biobased epoxy resins. The lignin-derived epoxy prepolymers could be used to replace 25-75% of the bisphenol A diglycidyl ether equivalent, leading to increases of up to 52% in the flexural modulus and up to 38% in the flexural strength. Improvements in the flexural strength were attributed to the oligomeric products present in the lignin hydrogenolysis oil. These results indicate lignin hydrogenolysis products have potential as sustainable biobased polyols in the synthesis of high performance epoxy resins.

  8. Reaction catalysts of urea-formaldehyde resin, as related to strength properties of southern pine particleboard

    Science.gov (United States)

    C. -Y. Hse

    1974-01-01

    Twelve resins were formulated with factorial combinations of three alkaline catalysts (i.e., somdium hydroxide, hexamethylenetetramine, and triethanolamine) and four acidic catalysts (i.e., acetic acid, hydrochloric acid, ammonium chloride, and phosphoric acid). The resins were replicated.

  9. Correlation between the cytotoxicity of self-etching resin cements and the degree of conversion

    Directory of Open Access Journals (Sweden)

    Luís FSA Morgan

    2015-01-01

    Conclusion: These results indicate that photopolymerization of dual cure self-etching resin cements decrease toxic effects on cell culture. Adequate photopolymerization should be considered during cementation when using dual polymerization self-etching resin cements.

  10. Synthesis, Characterization and Application of a New Chelating Resin Containing 2-(4-Methylbenzylidene)hydrazone

    National Research Council Canada - National Science Library

    Kumar, Rajesh; Jain, S.K

    2011-01-01

    ...–divinylbenzene copolymeric resin has been explored in this study. The structure of the functionalized resin was confirmed by FT-IR spectroscopy and its use for the adsorption of Ni(II) and Co(II...

  11. Shear bond strength of a self‑etched resin cement to an indirect ...

    African Journals Online (AJOL)

    2014-11-15

    Nov 15, 2014 ... Nigerian Journal of Clinical Practice • May-Jun 2015• Vol 18 • Issue 3. Abstract ... Key words: Composite resins, dental bonding, resin cements, surface properties ... etching effect of Er, Cr: YSGG laser on indirect composite.

  12. Resin-modified and conventional glass ionomer restorations in primary teeth: 8-year results

    DEFF Research Database (Denmark)

    Qvist, V.; Manscher, E.; Teglers, P.T.

    2004-01-01

    clinical trial, cariostatic effects, dental restorations, glass ionomer cement, long-term behaviour, pedodontics, resin-modified glass ionomer......clinical trial, cariostatic effects, dental restorations, glass ionomer cement, long-term behaviour, pedodontics, resin-modified glass ionomer...

  13. Color and Gloss of Nano-Filled Resin-Modified Glass Ionomers and Resin Composites.

    Science.gov (United States)

    Vance, Marc; Lawson, Nathaniel C; Rupal, Manpreet; Beck, Preston; Burgess, John O

    2015-01-01

    The study aims to compare in vitro stain resistance, color stability, gloss, and gloss retention of a nano-filled resin-modified glass ionomers (RMGIs) to a traditional RMGI and resin-based composites (RBCs). Specimens (N = 20) were fabricated from a nano-filled RBC (Filtek Supreme Plus, 3M ESPE, St. Paul, MN, USA), a nanohybrid RBC (Clearfil Majesty Esthetic, Kuraray; Tokyo, Japan), a nano-filled RMGI (Ketac Nano, 3M ESPE), and traditional RMGI (Fuji II LC, GC America, Chicago, IL, USA). L*a*b* values were recorded with a spectrophotometer, and gloss was measured with a glossmeter. For each material, 10 specimens were stored in distilled water in darkness for 1 week and 10 specimens were placed in a staining solution for 1 week. After storage, specimens were cleaned and L*a*b* and gloss measurements were remeasured. Data were analyzed by analysis of variance (ANOVA) and Tukey analyses. Regarding color change, materials ranked: Ketac = Fuji > Filtek > Clearfil in water, and Ketac > Fuji > Filtek > Clearfil in staining solution. Prior to storage, the initial gloss of the materials ranked: Filtek ≥ Clearfil ≥ Ketac > Fuji. After storage, the materials ranked: Filtek = Clearfil > Ketac > Fuji in water, and Filtek > Clearfil > Ketac > Fuji in staining solution. Gloss retention was similar for all materials in water and gloss retention ranked: Filtek = Clearfil > Ketac = Fuji in staining solution. The nano-RMGI showed less stain resistance but higher gloss than the traditional RMGI. Both RMGIs had more color change, less stain resistance, lower gloss and less gloss retention than the RBCs. The clinician should be aware that the use of a nano-RMGI may improve the gloss of an RMGI restoration; however, color change will likely occur, particularly if the patient consumes a staining diet. © 2014 Wiley Periodicals, Inc.

  14. Substitution determination of Fmoc‐substituted resins at different wavelengths

    Science.gov (United States)

    Kley, Markus; Bächle, Dirk; Loidl, Günther; Meier, Thomas; Samson, Daniel

    2017-01-01

    In solid‐phase peptide synthesis, the nominal batch size is calculated using the starting resin substitution and the mass of the starting resin. The starting resin substitution constitutes the basis for the calculation of a whole set of important process parameters, such as the number of amino acid derivative equivalents. For Fmoc‐substituted resins, substitution determination is often performed by suspending the Fmoc‐protected starting resin in 20% (v/v) piperidine in DMF to generate the dibenzofulvene–piperidine adduct that is quantified by ultraviolet–visible spectroscopy. The spectrometric measurement is performed at the maximum absorption wavelength of the dibenzofulvene–piperidine adduct, that is, at 301.0 nm. The recorded absorption value, the resin weight and the volume are entered into an equation derived from Lambert–Beer's law, together with the substance‐specific molar absorption coefficient at 301.0 nm, in order to calculate the nominal substitution. To our knowledge, molar absorption coefficients between 7100 l mol−1 cm−1 and 8100 l mol−1 cm−1 have been reported for the dibenzofulvene–piperidine adduct at 301.0 nm. Depending on the applied value, the nominal batch size may differ up to 14%. In this publication, a determination of the molar absorption coefficients at 301.0 and 289.8 nm is reported. Furthermore, proof is given that by measuring the absorption at 289.8 nm the impact of wavelength accuracy is reduced. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd. PMID:28635051

  15. Thermoset Blends of an Epoxy Resin and Polydicyclopentadiene

    Energy Technology Data Exchange (ETDEWEB)

    Rohde, Brian J.; Le, Kim Mai; Krishnamoorti, Ramanan; Robertson, Megan L.

    2016-12-13

    The mechanical properties of two chemically distinct and complementary thermoset polymers were manipulated through development of thermoset blends. The thermoset blend system was composed of an anhydride-cured diglycidyl ether of bisphenol A (DGEBA)-based epoxy resin, contributing high tensile strength and modulus, and polydicyclopentadiene (PDCPD), which has a higher toughness and impact strength as compared to other thermoset polymers. Ultra-small-angle and small-angle X-ray scattering analysis explored the morphology of concurrently cured thermoset blends, revealing a macroscopically phase separated system with a surface fractal structure across blended systems of varying composition. The epoxy resin rich and PDCPD rich phases exhibited distinct glass transitions (Tg’s): the Tg observed at higher temperature was associated with the epoxy resin rich phase and was largely unaffected by the presence of PDCPD, whereas the PDCPD rich phase Tg systematically decreased with increasing epoxy resin content due to inhibition of dicyclopentadiene ring-opening metathesis polymerization. The mechanical properties of these phase-separated blends were in reasonable agreement with predictions by the rule of mixtures for the blend tensile strength, modulus, and fracture toughness. Scanning electron microscopy analysis of the tensile and fracture specimen fracture surfaces showed an increase in energy dissipation mechanisms, such as crazing, shear banding, and surface roughness, as the fraction of the more ductile component, PDPCD, increased. These results present a facile method to tune the mechanical properties of a toughened thermoset network, in which the high modulus and tensile strength of the epoxy resin can be largely retained at high epoxy resin content in the blend, while increasing the fracture toughness.

  16. Fatigue resistance of CAD/CAM resin composite molar crowns.

    Science.gov (United States)

    Shembish, Fatma A; Tong, Hui; Kaizer, Marina; Janal, Malvin N; Thompson, Van P; Opdam, Niek J; Zhang, Yu

    2016-04-01

    To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. Fully anatomically shaped monolithic resin composite molar crowns (Lava Ultimate, n=24) and leucite reinforced glass-ceramic crowns (IPS Empress CAD, n=24) were fabricated using CAD/CAM systems. Crowns were cemented on aged dentin-like resin composite tooth replicas (Filtek Z100) with resin-based cements (RelyX Ultimate for Lava Ultimate or Multilink Automix for IPS Empress). Three step-stress profiles (aggressive, moderate and mild) were employed for the accelerated sliding-contact mouth-motion fatigue test. Twenty one crowns from each group were randomly distributed among these three profiles (1:2:4). Failure was designated as chip-off or bulk fracture. Optical and electron microscopes were used to examine the occlusal surface and subsurface damages, as well as the material microstructures. The resin composite crowns showed only minor occlusal damage during mouth-motion step-stress fatigue loading up to 1700N. Cross-sectional views revealed contact-induced cone cracks in all specimens, and flexural radial cracks in 2 crowns. Both cone and radial cracks were relatively small compared to the crown thickness. Extending these cracks to the threshold for catastrophic failure would require much higher indentation loads or more loading cycles. In contrast, all of the glass-ceramic crowns fractured, starting at loads of approximately 450N. Monolithic CAD/CAM resin composite crowns endure, with only superficial damage, fatigue loads 3-4 times higher than those causing catastrophic failure in glass-ceramic CAD crowns. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Vitrification of cesium-contaminated organic ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Sargent, Jr., Thomas N. [Clemson Univ., SC (United States)

    1994-08-01

    Vitrification has been declared by the Environmental Protection Agency (USEPA) as the Best Demonstrated Available Technology (BDAT) for the permanent disposal of high-level radioactive waste. Savannah River Site currently uses a sodium tetraphenylborate (NaTPB) precipitation process to remove Cs-137 from a wastewater solution created from the processing of nuclear fuel. This process has several disadvantages such as the formation of a benzene waste stream. It has been proposed to replace the precipitation process with an ion exchange process using a new resorcinol-formaldehyde resin developed by Savannah River Technical Center (SRTC). Preliminary tests, however, showed that problems such as crust formation and a reduced final glass wasteform exist when the resin is placed in the melter environment. The newly developed stirred melter could be capable of overcoming these problems. This research explored the operational feasibility of using the stirred tank melter to vitrify an organic ion exchange resin. Preliminary tests included crucible studies to determine the reducing potential of the resin and the extent of oxygen consuming reactions and oxygen transfer tests to approximate the extent of oxygen transfer into the molten glass using an impeller and a combination of the impeller and an external oxygen transfer system. These preliminary studies were used as a basis for the final test which was using the stirred tank melter to vitrify nonradioactive cesium loaded organic ion exchange resin. Results from this test included a cesium mass balance, a characterization of the semi-volatile organic compounds present in the off gas as products of incomplete combustion (PIC), a qualitative analysis of other volatile metals, and observations relating to the effect the resin had on the final redox state of the glass.

  18. Monoclonal antibody fragment removal mediated by mixed mode resins.

    Science.gov (United States)

    O'Connor, Ellen; Aspelund, Matthew; Bartnik, Frank; Berge, Mark; Coughlin, Kelly; Kambarami, Mutsa; Spencer, David; Yan, Huiming; Wang, William

    2017-05-26

    Efforts to increase monoclonal antibody expression in cell culture can result in the presence of fragmented species requiring removal in downstream processing. Capto adhere, HEA Hypercel, and PPA Hypercel anion exchange/hydrophobic interaction mixed mode resins were evaluated for their fragment removal capabilities and found to separate large hinge IgG1 antibody fragment (LHF) from monomer. Removal of greater than 75% of LHF population occurred at pH 8 and low conductivity. The mechanism of fragment removal was investigated in two series of experiments. The first experimental series consisted of comparison to chromatographic behavior on corresponding single mode resins. Both single mode anion exchange and hydrophobic interaction resins failed to separate LHF. The second experimental series studied the impact of phase modifiers, ethylene glycol, urea, and arginine on the mixed mode mediated removal. The addition of ethylene glycol decreased LHF removal by half. Further decreases in LHF separation were seen upon incubation with urea and arginine. Therefore, it was discovered that the purification is the result of a mixed mode phenomena dominated by hydrophobic interaction and hydrogen bonding effects. The site of interaction between the LHF and mixed mode resin was determined by chemical labeling of lysine residues with sulfo-NHS acetate. The labeling identified the antibody hinge and light chain regions as mediating the fragment separation. Sequence analysis showed that under separation conditions, a hydrophobic proline patch and hydrogen bonding serine and threonine residues mediate the hinge interaction with the Capto adhere ligand. Additionally, a case study is presented detailing the optimization of fragment removal using Capto adhere resin to achieve purity and yield targets in a manufacturing facility. This study demonstrated that mixed mode resins can be readily integrated into commercial antibody platform processes when additional chromatographic abilities

  19. ADHESIVE SYSTEM AFFECTS REPAIR BOND STRENGTH OF RESIN COMPOSITE

    OpenAIRE

    IRMAK, Özgür; Özge ÇELIKSÖZ; Begüm YILMAZ; Batu Can YAMAN

    2017-01-01

    Purpose: This study evaluated the effects of different adhesive systems on repair bond strength of aged resin composites. Materials and Methods: Ninety composite discs were built and half of them were subjected to thermal aging. Aged and non-aged specimens were repaired with resin composite using three different adhesive systems; a two-step self-etch adhesive, a two-step total-etch adhesive and a one-step self-etch adhesive; then they were subjected to shear forces. Data were analyzed stat...

  20. Electrical properties of epoxy resin based nano-composites

    Energy Technology Data Exchange (ETDEWEB)

    Tuncer, Enis [High Voltage and Dielectrics, Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Sauers, Isidor [High Voltage and Dielectrics, Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); James, D Randy [High Voltage and Dielectrics, Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Ellis, Alvin R [High Voltage and Dielectrics, Applied Superconductivity Group, Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Paranthaman, M Parans [Materials Chemistry Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Aytug, Tolga [Materials Chemistry Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Sathyamurthy, Srivatsan [Materials Chemistry Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); More, Karren L [Microscopy Microanalysis and Microstructures Group, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37832-6122 (United States); Li, Jing [Superconductive and Energy Efficient Materials Group, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Goyal, Amit [Superconductive and Energy Efficient Materials Group, Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2007-01-17

    We investigate the electrical properties of composite materials prepared as nano- and sub-micron-scale metal-oxide particles embedded in a commercial resin. The filler particles are barium titanate and calcium copper titanate. The physical and structural characteristics of the constituents and the fabricated composites are reported. Electrical characterization of the composite samples is performed using time- and frequency-domain dielectric spectroscopy techniques. The electrical breakdown strength of samples with nano- and sub-micron-sized particles have better electrical insulation properties than the unfilled resin.

  1. Application of living microbial cells entrapped with synthetic resin prepolymers.

    Science.gov (United States)

    Fukui, S; Tanaka, A

    1989-12-01

    Living and growing microbial cells were immobilized by entrapping in synthetic resin gels prepared from their prepolymers, and used in the production of various useful substances. The production of the desired metabolites and also both the activity and the stability of the catalytic systems were seriously affected by the physico-chemical properties of the prepolymers, and those of the resin gels subsequently formed, such as gel network, hydrophilicity-hydrophobicity balance and ionic nature, as well as by the type of bioreactors. Hydroxylation of steroids and production of antibiotics, polypeptides and other biologically active substances, and the effects of gel properties on them are discussed as examples.

  2. Solid support resins and affinity purification mass spectrometry.

    Science.gov (United States)

    Havis, Spencer; Moree, Wilna J; Mali, Sujina; Bark, Steven J

    2017-02-28

    Co-affinity purification-mass spectrometry (CoAP-MS) is a primary technology for elucidating the protein-protein interactions that form the basis of all biological processes. A critical component of CoAP-MS is the affinity purification (AP) of the bait protein, usually by immobilization of an antibody to a solid-phase resin. This Minireview discusses common resins, reagents, tagging methods, and their consideration for successful AP of tagged proteins. We discuss our experiences with different solid supports, their impact in AP experiments, and propose areas where chemistry can advance this important technology.

  3. Characterization of selected LDEF polymer matrix resin composite materials

    Science.gov (United States)

    Young, Philip R.; Slemp, Wayne S.; Witte, William G., Jr.; Shen, James Y.

    1991-01-01

    The characterization of selected graphite fiber reinforced epoxy (934 and 5208) and polysulfone (P1700) matrix resin composite materials which received 5 years and 10 months of exposure to the LEO environment on the Long Duration Exposure Facility is reported. Resin loss and a decrease in mechanical performance as well as dramatic visual effects were observed. However, chemical characterization including infrared, thermal, and selected solution property measurements showed that the molecular structure of the polymeric matrix had not changed significantly in response to this exposure. The potential effect of a silicon-containing molecular contamination of these specimens is addressed.

  4. Toughened epoxy resin system and a method thereof

    Science.gov (United States)

    Janke, Christopher J.; Dorsey, George F.; Havens, Stephen J.; Lopata, Vincent J.

    1998-01-01

    Mixtures of epoxy resins with cationic initiators are curable under high energy ionizing radiation such as electron beam radiation, X-ray radiation, and gamma radiation. The composition of this process consists of an epoxy resin, a cationic initiator such as a diaryliodonium or triarylsulfonium salt of specific anions, and a toughening agent such as a thermoplastic, hydroxy-containing thermoplastic oligomer, epoxy-containing thermoplastic oligomer, reactive flexibilizer, rubber, elastomer, or mixture thereof. Cured compositions have high glass transition temperatures, good mechanical properties, and good toughness. These properties are comparable to those of similar thermally cured epoxies.

  5. Fluorinated epoxy resins with high glass transition temperatures

    Science.gov (United States)

    Griffith, James R.

    1991-01-01

    Easily processed liquid resins of low dielectric constants and high glass transition temperatures are useful for the manufacture of certain composite electronic boards. That combination of properties is difficult to acquire when dielectric constants are below 2.5, glass transition temperatures are above 200 C and processability is of conventional practicality. A recently issued patent (US 4,981,941 of 1 Jan. 1991) teaches practical materials and is the culmination of 23 years of research and effort and 15 patents owned by the Navy in the field of fluorinated resins of several classes. In addition to high fluorine content, practical utility was emphasized.

  6. Review of methyl methacrylate (MMA)/tributylborane (TBB)-initiated resin adhesive to dentin

    OpenAIRE

    Taira, Yohsuke; Imai, Yohji

    2014-01-01

    This review, focusing mainly on research related to methyl methacrylate/tributylborane (MMA/TBB) resin, presents the early history of dentin bonding and MMA/TBB adhesive resin, followed by characteristics of resin bonding to dentin. Bond strengths of MMA/TBB adhesive resin to different adherends were discussed and compared with other bonding systems. Factors affecting bond strength (such as conditioners, primers, and medicaments used for dental treatment), bonding mechanism, and polymerizatio...

  7. Flame retardant materials based on BDM/DBA resin and organic-inorganic additives

    OpenAIRE

    Wang, Zheng

    2017-01-01

    2,2’-diallyl bisphenol A (DBA) modified bismaleimide resins (BDM) are widely used as polymer matrix of high-performance composites in the field of aerospace, transportation, machinery, and electronics. This kind of resin has excellent properties, including good thermal stability, good processing performance, high mechanical strength, excellent dielectric properties, etc. However, as for most organic resins, the flame retardancy of the BMI resins is not so good. In order to expand the use of t...

  8. Epoxy/carbon composite resins in dentistry: mechanical properties related to fiber reinforcements.

    Science.gov (United States)

    Viguie, G; Malquarti, G; Vincent, B; Bourgeois, D

    1994-09-01

    Composite carbon/epoxy resin techniques for restorative dentistry have improved with the development of various composite resins classified according to fiber reinforcement, such as short fibers, woven materials, or long unidirectional fibers. This study of the mechanical properties with three-point flexion enabled comparison of the flexural strengths. The modulus of elasticity of different composite resin materials was determined so that the appropriate reinforced composite resin could be selected for specific clinical conditions.

  9. Ultramorphology of pre-treated adhesive interfaces between self-adhesive resin cement and tooth structures

    OpenAIRE

    Pereira,Carolina Nemesio de Barros; DALEPRANE,Bruno; MIRANDA,Giovani Lana Peixoto de; Magalhães,Cláudia Silami de; Moreira, Allyson Nogueira

    2017-01-01

    Abstract Introduction Convencional resin cements can be used in combination with a total-etch system in a conventional mode or as self-adhesive resin cements. The latter are less technique sensitive and able to bond to dental tissues without previous treatment or adhesive layer and requires only a single step to be applied to dental structures. Objective To compare qualitatively the adhesive interfaces of two self-adhesive resin cements and one conventional resin cement after different toot...

  10. A new configuration of membrane stack for retrieval of nickel absorbed in resins*

    OpenAIRE

    Chen, Xue-Fen; Wu, Zu-cheng

    2005-01-01

    A new configuration integrated ion exchange effect with both electro-migration and electrochemical reaction in a single cell was developed to effectively retrieve metal ions from simulated wastewater using ion exchange resins without additive chemicals. By simply assembling cation exchange resins and anion exchange resins separated by homogeneous membranes, we found that the system will always be acidic in the concentrate compartment so that ion exchange resins could be in-situ regenerated wi...

  11. Short Communication. Resin tapping activity as a contribution to the management of maritime pine forest

    Directory of Open Access Journals (Sweden)

    Amélia Palma

    2016-07-01

    Full Text Available Aim of the study: In this work potential resin yield in a region of high forest ability where maritime pine is the main species was estimated in order to understand the viability of promoting resin exploitation. Area of study: This study was conducted in Castro Daire County in central region of Portugal. Material and methods: To quantify the resin yield of trees tapped for the first time two plots were installed in a maritime pine stand with average tree age 65 years. Before the beginning of the resin tapping, dendrometric tree variables were measured. Also, in a neighbouring stand, 25 trees were selected to check the relation between tree dbh and resin yield. Gum resin from every tree was weighted during the season. Estimates of potential resin yield in Castro Daire County were made based on data from National Forest Inventory plots, resin tapping legislation and resin yield values obtained in the field. Two scenarios were considered: high and low resin yield. To understand the intentions of forest owners towards restarting resin tapping activity 16 maritime pine forest owners were interviewed. Main results: The results point out a high yield potential capacity for gum resin production in the County: values between 2,025 and 5,873 tons were obtained. Research highlights: Results may highlight the important socio-economical role of the resin tapping activity and can be used to support national forest policies to the resin sector and give forest owners motivation to reactivate resin tapping activity. Keywords: non-wood forest product; resin yield potential; forest owner.

  12. Comparison of Microleakage of Composite Resin Veneering Systems at the Alloy Interface

    Science.gov (United States)

    1988-09-01

    technique that there is leakage around resin veneers in gold crowns. Microleakage studies have been used primarily for the evaluation of direct...investigation is to evaluate the bond between veneering composite resin and metal substructure. Measurement of microleakage at the composite resin-alloy...34OVERPRINT" COMPARISON OF MICROLEAKAGE OF COMPOSITE RESIN VENEERING SYSTEMS AT THE ALLOY INTERFACE A THESIS Presented to the Faculty of The University

  13. Characterization of high-pressure resin transfer molding process variants for manufacturing high-performance composites

    OpenAIRE

    Chaudhari, Raman

    2014-01-01

    The current developments in the Resin Transfer Molding (RTM) process for the automotive industry are strongly driven by the need for automotive light-weight design and high volume manufacturing capacity. In order to adapt the RTM process for industrial scale manufacturing of the automotive components it is essential to implement newly developed fast curing resin systems. If such resin systems shall be implemented in the RTM process, then it raises the necessity to achieve shorter resin inject...

  14. A comparative study to determine strength of autopolymerizing acrylic resin and autopolymerizing composite resin influenced by temperature during polymerization: An In Vitro study

    Directory of Open Access Journals (Sweden)

    Anuj Chhabra

    2017-01-01

    Full Text Available Aim: Temporary coverage of a prepared tooth is an important step during various stages of the fixed dental prosthesis. Provisional restorations should satisfy proper mechanical requirements to resist functional and nonfunctional loads. A few studies are carried out regarding the comparison of the effect of curing environment, air and water, on mechanical properties of autopolymerizing acrylic and composite resin. Hence, the aim of this study was to compare the transverse strength of autopolymerizing acrylic resin and autopolymerizing composite resin as influenced by the temperature of air and water during polymerization. Materials and Methods: Samples of autopolymerizing acrylic resin and composite resin were prepared by mixing as per manufacturer's instructions and were placed in a preformed stainless steel mold. The mold containing the material was placed under different controlled conditions of water temperature and air at room temperature. Polymerized samples were then tested for transverse strength using an Instron universal testing machine. Results: Alteration of curing condition during polymerization revealed a significant effect on the transverse strength. The transverse strength of acrylic resin specimens cured at 60°C and composite resin specimens cured at 80°C was highest. Polymerizing the resin in cold water at 10°C reduced the mechanical strength. Conclusions: Polymerization of the resin in hot water greatly increased its mechanical properties. The method of placing resin restoration in hot water during polymerization may be useful for improving the mechanical requirements and obtaining long-lasting performance.

  15. Can simultaneous contact allergies to phenyl glycidyl ether and epoxy resins of the bisphenol A/F-types be explained by contamination of the epoxy resins?

    Science.gov (United States)

    Pontén, Ann; Zimerson, Erik; Bruze, Magnus

    2008-11-01

    Simultaneous contact allergies to epoxy resins based on diglycidyl ether of bisphenol A (DGEBA-R) or epoxy resins of the bisphenol F-type and the reactive diluent phenyl glycidyl ether (PGE) have been reported. The reason might be cross-reactivity, exposure to an epoxy resin system with PGE as a component, or contamination by PGE in the epoxy resin. To study contamination by PGE, 20 commercial epoxy resins were analysed for the presence of PGE. To study contact allergy to PGE and its relation to epoxy resins by inserting PGE in the standard series. Among 2227 patients, 7 reacted to PGE. Of 23 (30%) patients, 7 with contact allergy to DGEBA-R and 7/19 (37%) with contact allergy to an epoxy resin of the bisphenol F-type reacted to PGE. All 7 patients with contact allergy to PGE reacted both to the DGEBA-R and to the epoxy resin of the bisphenol F-type. PGE was found in 90% of the investigated resins. The amounts of PGE ranged between 0.004% w/w and 0.18% w/w. Most probably, the presence of PGE as a contaminant in epoxy resins is of minor importance for the sensitization, but possibly the contamination of PGE might elicit contact dermatitis in individuals with a high reactivity to PGE.

  16. Comparison of Shear Bond Strength of Resin-Modified Glass Ionomer and Composite Resin to Three Pulp Capping Agents

    Directory of Open Access Journals (Sweden)

    Amir Ahmad Ajami

    2013-08-01

    Full Text Available Background and aims. Present study was designed to compare the bonding strength of resin-modified glass ionomer (RMGI and composite resin to mineral trioxide aggregate (MTA, MTA mixed with Na2HPO4 (NAMTA, and calciumenriched mixture (CEM. Materials and methods. Thirty specimens of each CEM, NAMTA, and MTA were prepared. Composite and RMGI restorations were then placed on the samples (15 samples in six subgroups. Shear bond strength was assessed using universal testing machine. Data were analyzed with two-way ANOVA and post-hoc Tukey test. To compare the bond strength in subgroups, one-away ANOVA was applied. Significance level was set at P 0.05. Conclusion. Regarding shear bond strength to the tested substrates, composite was shown to be superior to RMGI. The bond of resin composite to MTA was weaker than that to CEM and NAMTA.

  17. The Effect of Nanoclay on Physicochemical, Mechanical and Thermal Properties of New Urea- Glyoxal Resin

    Directory of Open Access Journals (Sweden)

    hamed yonesi korekhili

    2015-05-01

    Full Text Available In order to eliminate the harm of formaldehyde from panels bonded with UF resin to environment and human health at the source, the low volatile and nontoxic aldehyde of glyoxyal (G was chosen to react with urea (U to prepare the wood adhesive of urea-glyoxal (UG resin a substitute for urea-formaldehyde (UF resin. The urea-glyoxal (UG resin was synthesized under weak acid conditions, and its different properties were measured. Also, the effect of nanoclay on physico-chemical, thermal and mechanical properties of UG resin was investigated. For this purpose, the prepared UG resin was mixed with 1, 2 and 3 wt% nanoclay by mechanically stirring for 5 min at room temperature. The physico-chemical properties (such as SPG, viscosity, solid content and gelation time and dry shear strength of the prepared resin were measured according to standard methods. Also, the effect of nanoclay on curing temperature of UG resin was analyzed by Differential Scanning Calorimetry (DSC device. The physico-chemical test results indicated that addition of nanoclay increased SPG, viscosity and solid content of UG resin and decreased gelation time in the prepared resin. Dry shear strength test results showed that increasing nanoclay content from 1 to 3 wt% increased shear strength of UG resin; as the panels containing 3% nanoclay exhibited the highest shear strength value and wood failure percentage. Based on DSC test results, hardening rate as well as enthalpy value of the prepared UG resin was decreased by addition of nanoclay.

  18. Effect of aluminium oxide particle sandblasting on the artificial tooth-resin bond.

    Science.gov (United States)

    Consani, Rafael Leonardo Xediek; Richter, Marina Martorano; Mesquita, Marcelo Ferraz; Sinhoreti, Mario Alexandre Coelho; Guiraldo, Ricardo Danil

    2010-11-01

    The influence of tooth ridge-lap surface sandblasting with aluminium oxide particles was evaluated on the adhesion of artificial teeth to acrylic resins. Specimens were made with the acrylic resin adhered to teeth (BioCler GII), according to an unmodified surface, glossy surface sandblasted with 50-μm particles and conventional (Classico) or microwaved (Onda Cryl) resin, and a glossy surface sandblasted with 100-μm particles and Classico or Onda Cryl resin. The shear bond test was performed in an Instron machine using a 500-N load cell and cross-speed of 1 mm/min. The analysis of variance revealed significant difference in the tooth-resin shear bond strength for resin, surface treatment, and interaction. For conventional resin, control, 50-, and 100-μm particles showed statistically-different values; for microwaved resin, the control showed less statistical difference when compared to 50- and 100-μm particle treatments; for between resins, only the 100-μm particle treatment showed statistically-different values, with lower values for the microwaved resin. Mixed failures (cohesive in the resin and adhesive) were predominantly observed in all groups. Mixed (cohesive in the tooth and adhesive) or adhesive failures were not observed. Sandblasting with different aluminium oxide particle sizes produced different effects on the shear strength values of the tooth-resin bond. © 2010 Blackwell Publishing Asia Pty Ltd.

  19. 77 FR 31875 - Certain Rubber Resins and Processes for Manufacturing Same; Notice of Receipt of Complaint...

    Science.gov (United States)

    2012-05-30

    ... COMMISSION Certain Rubber Resins and Processes for Manufacturing Same; Notice of Receipt of Complaint... complaint entitled Certain Rubber Resins and Processes for Manufacturing Same, DN 2897; the Commission is... importation of certain rubber resins and processes for manufacturing same. The complaint names as respondents...

  20. An outbreak of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener

    NARCIS (Netherlands)

    de Wit, F. S.; de Groot, A. C.; Weyland, J. W.; Bos, J. D.

    1988-01-01

    8 cases of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener are presented. Most patients had used nail lacquers containing this resin for many years without trouble, but became sensitized to the resin shortly after the introduction of this particular nail hardener. A

  1. Effect of monomer composition on crystal growth by resin containing bioglass.

    Science.gov (United States)

    Hashimoto, Masanori; Iijima, Masahiro; Nagano, Futami; Ohno, Hiroki; Endo, Kazuhiko

    2010-07-01

    This study evaluated the effect of resin monomer composition on crystal growth at the interface between the resin/bioglass composites and water. Light-cured resin that contained 2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl], 2-hydroxyethyl methacrylate, and triethylene glycol dimethacrylate with different compositions were used. Resin/bioglass composites were prepared with 40 mass% bioglass and 60 mass% resin. The resin/bioglass composites were stored in deionized distilled water for 24 h (control group) or 3-12 months (experimental groups). After water storage, the disk surfaces were examined by light- and scanning electron microscopy. Chemical states of the crystals were analyzed by laser-Raman spectroscopy and micro-X-ray diffractometry. The microscopic analysis showed crystal on the resin disks surface after six months of water storage for hydrophilic resins. However, there was no crystal formation in the control and the experimental groups of specimens of hydrophobic resins. Raman analysis showed the chemical states of the crystals formed on the resin matrix and bioglass to be different. The micro-X-ray analysis of crystals on resin disks identified them to be calcium carbonate. This crystal formation occurred in water instead of simulated body fluid. In conclusion, the resin monomer compositions affected the ability to induce crystal growth on the surfaces of disks containing bioglass. (c) 2010 Wiley Periodicals, Inc.

  2. 21 CFR 177.2710 - Styrene-divinylbenzene resins, cross-linked.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Styrene-divinylbenzene resins, cross-linked. 177.2710 Section 177.2710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... resins, cross-linked. Styrene-divinylbenzene cross-linked copolymer resins may be safely used as articles...

  3. Viricidal Capability of Resin-Triiodide Demand-Type Disinfectant †

    Science.gov (United States)

    Fina, Louis R.; Hassouna, Nadia; Horacek, Gary L.; Lambert, John P.; Lambert, Jack L.

    1982-01-01

    Polyoma, Newcastle disease virus, and adenovirus, as well as two coliphages, lambda and T4, were inactivated by strong base quaternary ammonium anion-exchange resin-triiodide. Organic matter interfered with viral inactivation capability of the resin-triiodide. The viruses, as they were being inactivated by the resin disinfectant beads, were not retained or filtered by the beads. PMID:6297389

  4. Viricidal Capability of Resin-Triiodide Demand-Type Disinfectant †

    OpenAIRE

    Fina, Louis R.; Hassouna, Nadia; Horacek, Gary L.; Lambert, John P.; Lambert, Jack L.

    1982-01-01

    Polyoma, Newcastle disease virus, and adenovirus, as well as two coliphages, lambda and T4, were inactivated by strong base quaternary ammonium anion-exchange resin-triiodide. Organic matter interfered with viral inactivation capability of the resin-triiodide. The viruses, as they were being inactivated by the resin disinfectant beads, were not retained or filtered by the beads.

  5. 21 CFR 177.1570 - Poly-1-butene resins and butene/ethylene copolymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Poly-1-butene resins and butene/ethylene copolymers... resins and butene/ethylene copolymers. The poly-1-butene resins and butene/ethylene copolymers identified... the catalytic polymerization of 1-butene liquid monomer. Butene/ethylene copolymers are produced by...

  6. 21 CFR 177.1340 - Ethylene-methyl acrylate copolymer resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-methyl acrylate copolymer resins. 177.1340... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1340 Ethylene-methyl acrylate copolymer resins. Ethylene-methyl acrylate copolymer resins may be safely used as articles or components of...

  7. Effect of accelerated aging on the microhardness and color stability of flexible resins for dentures

    Directory of Open Access Journals (Sweden)

    Marcelo Coelho Goiato

    2010-03-01

    Full Text Available Acrylic resins have been widely used due to their acceptable esthetics and desirable characteristics such as easy handling, good thermal conductivity, low permeability to oral fluids and color stability. Flexible resins were introduced on the market as an alternative to the use of conventional acrylic resins in the construction of complete and partial removable dentures. Although these resins present advantages in terms of esthetics and comfort, studies assessing chromatic and microhardness alterations of these materials are still scarce in the related literature. The aim of this study was to evaluate the chromatic and microhardness alterations of two commercial brands of flexible resins in comparison to the conventional resin Triplex when submitted to accelerated aging. The resins were manipulated according to manufacturers' instructions and inserted into a silicone matrix to obtain 21 specimens divided into 3 groups: Triplex, Ppflex and Valplast. Triplex presented the highest microhardness value (p < 0.05 for all the aging periods, which was significantly different from that of the other resins, followed by the values of Valplast and Ppflex. Comparison between the flexible resins (Ppflex and Valplast revealed a statistically significant difference (p < 0.05 as regards color. The flexible resin Ppflex and the conventional resin Triplex presented no statistically significant difference (p < 0.05 as regards aging. The accelerated aging significantly increased the microhardness values of the resins, with the highest values being observed for Triplex. Valplast presented the greatest chromatic alteration after accelerated aging.

  8. 21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Partial phosphoric acid esters of polyester resins... COMPONENTS OF COATINGS Substances for Use as Components of Coatings § 175.260 Partial phosphoric acid esters of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section...

  9. 77 FR 1267 - National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins...

    Science.gov (United States)

    2012-01-09

    ... Hazardous Air Pollutant Emissions: Group IV Polymers and Resins; Pesticide Active Ingredient Production; and... Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers and Resins; Pesticide Active... Polymers and Resins; NESHAP for Pesticide Active Ingredient Production; and NESHAP for Polyether Polyols...

  10. 76 FR 22565 - National Emission Standards for Hazardous Air Pollutant Emissions: Group I Polymers and Resins...

    Science.gov (United States)

    2011-04-21

    ... Hazardous Air Pollutant Emissions: Group I Polymers and Resins; Marine Tank Vessel Loading Operations... Polymers and Resins; Marine Tank Vessel Loading Operations; Pharmaceuticals Production; and the Printing... NESHAP include: National Emissions Standards for Group I Polymers and Resins (Butyl Rubber Production...

  11. Microhardness of resin composite materials light-cured through fiber reinforced composite.

    NARCIS (Netherlands)

    Fennis, W.M.M.; Ray, N.J.; Creugers, N.H.J.; Kreulen, C.M.

    2009-01-01

    OBJECTIVES: To compare polymerization efficiency of resin composite basing materials when light-cured through resin composite and fiber reinforced composite (FRC) by testing microhardness. METHODS: Simulated indirect restorations were prepared by application of resin composite (Clearfil AP-X) or FRC

  12. 21 CFR 872.3760 - Denture relining, repairing, or rebasing resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Denture relining, repairing, or rebasing resin. 872.3760 Section 872.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN..., repairing, or rebasing resin. (a) Identification. A denture relining, repairing, or rebasing resin is a...

  13. Resin secretory structures of Boswellia papyrifera and implications for frankincense yield.

    Science.gov (United States)

    Tolera, Motuma; Menger, David; Sass-Klaassen, Ute; Sterck, Frank J; Copini, Paul; Bongers, Frans

    2013-01-01

    Frankincense, a gum-resin, has been tapped from Boswellia papyrifera trees for centuries. Despite the intensive tapping and economic interest of B. papyrifera, information on the resin secretory structures, which are responsible for synthesis, storage and transport of frankincense, is virtually absent. This study describes the type, architecture and distribution of resin secretory structures of B. papyrifera and its relevance for the ecophysiology and economic use of the tree. The type and architecture of resin secretory structures present in bark and wood was investigated from transversal, tangential and radial sections of bark and wood samples. The diameter and density (number of resin canals mm(-2)) of axial resin canals were determined from digital images of thin sections across the different zones of inner bark. Resin canals form a three-dimensional network within the inner bark. Yet, the intact resin-conducting and producing network is on average limited to the inner 6·6 mm of the inner bark. Within the inner bark, the density of non-lignified axial resin canals decreases and the density of lignified resin canals increases from the vascular cambium towards the outer bark. In the wood, only radial resin canals were encountered. Frankincense tapping techniques can be improved based on knowledge of bark anatomy and distribution and architecture of resin secretory structures. The suggested new techniques will contribute to a more sustainable frankincense production that enhances the contribution of frankincense to rural livelihoods and the national economy.

  14. Resin duct characteristics in the wood of fire-scarred North American conifers

    Science.gov (United States)

    Estelle Arbellay; Markus Stoffel; Elaine K. Sutherland; Kevin T. Smith; Donald A. Falk

    2013-01-01

    Traumatic resin ducts form in xylem and phloem tissue of conifers in response to abiotic wounding, fungal invasion, and insect attack. Little is known about resin duct characteristics in the wood of fire-scarred trees. The aim of this study is to quantify changes in traits of both axial and radial resin ducts, along with those of associated epithelial cells and...

  15. 21 CFR 173.70 - Chloromethylated aminated styrene-divinylbenzene resin.

    Science.gov (United States)

    2010-04-01

    ... resin. 173.70 Section 173.70 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Chloromethylated aminated styrene-divinylbenzene resin. Chloromethylated aminated styrene-divinylbenzene copolymer... resin dispersion. (c) The additive is used as a decolorizing and clarification agent for treatment of...

  16. Color test for selective detection of secondary amines on resin and in solution

    DEFF Research Database (Denmark)

    Boas, Ulrik; Mirsharghi, Sahar

    2014-01-01

    Resins for solid-phase synthesis give orange to red-brown resin beads selectively when secondary amines are present on the resin when treated with a solution of acetaldehyde and an Fmoc-amino acid in NMP. The method shows good specificity and gives colorless beads when exposed to a variety of other...

  17. 40 CFR 721.5380 - Mixed alkyl phenolic novolak resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Mixed alkyl phenolic novolak resin... Specific Chemical Substances § 721.5380 Mixed alkyl phenolic novolak resin (generic). (a) Chemical... as mixed alkyl phenolic novolak resin (PMN P-98-718) is subject to reporting under this section for...

  18. Red-cockaded woodpecker cavity tree resin avoidance by southern flying squirrels

    Science.gov (United States)

    Richard R. Schaefer; Daniel Saenz

    1998-01-01

    While examining red-cockaded woodpecker (Picoides borealis) cavity contents in eastern Texas, the authors observed cavity tree resin avoidance by southern flying squirrels (Glaucomys volans). The tree surface around an active red-cockaded woodpecker cavity is coated with sticky resin which flows from resin wells created by the woodpecker. The southern flying squirrel...

  19. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bracket adhesive resin and tooth conditioner. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a device...

  20. Effect of denture cleansers on color stability, surface roughness, and hardness of different denture base resins.

    Science.gov (United States)

    Porwal, Anand; Khandelwal, Meenakshi; Punia, Vikas; Sharma, Vivek

    2017-01-01

    The purpose of this study was to evaluate the effect of different denture cleansers on the color stability, surface hardness, and roughness of different denture base resins. Three denture base resin materials (conventional heat cure resin, high impact resin, and polyamide denture base resin) were immersed for 180 days in commercially available two denture cleansers (sodium perborate and sodium hypochlorite). Color, surface roughness, and hardness were measured for each sample before and after immersion procedure. One-way analysis of variance and Tukey's post hoc honestly significant difference test were used to evaluate color, surface roughness, and hardness data before and after immersion in denture cleanser (α =0.05). All denture base resins tested exhibited a change in color, surface roughness, and hardness to some degree in both denture cleansers. Polyamides resin immersed in sodium perborate showed a maximum change in color after immersion for 180 days. Conventional heat cure resin immersed in sodium hypochlorite showed a maximum change in surface roughness and conventional heat cure immersed in sodium perborate showed a maximum change in hardness. Color changes of all denture base resins were within the clinically accepted range for color difference. Surface roughness change of conventional heat cure resin was not within the clinically accepted range of surface roughness. The choice of denture cleanser for different denture base resins should be based on the chemistry of resin and cleanser, denture cleanser concentration, and duration of immersion.

  1. Red-cockaded woodpeckers vs rat snakes: the effectiveness of the resin barrier

    Science.gov (United States)

    D. Craig Rudolph; Howard Kyle; Richard N. Conner

    1990-01-01

    Red-cockaded Woodpeckers (Picoides borealis) excavate resin wells in the immediate vicinity of roost and nest cavity entrances. Resin wells are worked regularly, resulting in a copious and persistent resin flow that coats the tree trunk, especially below cavity entrances. Red-cockaded Woodpeckers also scale loose bark from cavity trees and closely adjacent trees....

  2. Microleakage around zirconia crown margins after ultrasonic scaling with self-adhesive resin or resin modified glass ionomer cement.

    Science.gov (United States)

    Chang, Bright; Goldstein, Ronald; Lin, Chee Paul; Byreddy, Sudha; Lawson, Nathaniel C

    2017-12-01

    To measure microleakage around zirconia crown margins cemented with self-adhesive resin or resin modified glass ionomer (RMGI) cement after ultrasonic scaling. 16 molars were prepared for crowns (margin 0.5 mm coronal of cementum-enamel junction). Preparations were digitally scanned and zirconia crowns milled. Specimens were divided into two groups (n = 8): self-adhesive resin (RelyX Unicem 2) or resin modified glass ionomer (RMGI) (RelyX Luting Plus) cements. After cementation, specimens were ultrasonic scaled with a piezoelectric device (60 s, hand pressure). After thermocycling (20,000 cycles/5-55°C), specimens were immersed in 5 wt% fuchsine dye before sectioning bucco-lingually. Microleakage was examined under 40× light magnification. Statistical comparisons were made using a paired t test and a two-sample t test (α = .05). Ultrasonic scaling did not alter microleakage at the margins of crowns (P = .31). There was no significant difference in microleakage of scaled and untreated margins with the use of different cements (P = .21). The amount of microleakage around margins that were scaled was not significantly different between cements (P = .14). Untreated margins of crowns cemented with RelyX Luting Plus showed a significantly higher microleakage than those cemented with RelyX Unicem 2 (P = .005). Piezoelectric ultrasonic scaling did not increase microleakage at the margin of zirconia crowns cemented with self-adhesive resin or RMGI cements. Piezoelectric ultrasonic scaling around zirconia crowns did not impact marginal microleakage cemented with self-adhesive resin or RMGI cements. © 2017 Wiley Periodicals, Inc.

  3. Cariogenic bacteria degrade dental resin composites and adhesives.

    Science.gov (United States)

    Bourbia, M; Ma, D; Cvitkovitch, D G; Santerre, J P; Finer, Y

    2013-11-01

    A major reason for dental resin composite restoration replacement is related to secondary caries promoted by acid production from bacteria including Streptococcus mutans (S. mutans). We hypothesized that S. mutans has esterase activities that degrade dental resin composites and adhesives. Standardized specimens of resin composite (Z250), total-etch (Scotchbond Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 or uninoculated culture medium (control) for up to 30 days. Quantification of the BisGMA-derived biodegradation by-product, bishydroxy-propoxy-phenyl-propane (BisHPPP), was performed by high-performance liquid chromatography. Surface analysis of the specimens was performed by scanning electron microscopy (SEM). S. mutans was shown to have esterase activities in levels comparable with those found in human saliva. A trend of increasing BisHPPP release throughout the incubation period was observed for all materials and was more elevated in the presence of bacteria vs. control medium for EB and Z250, but not for SB (p adhesives; degree of degradation was dependent on the material's chemical formulation. This finding suggests that the resin-dentin interface could be compromised by oral bacteria that contribute to the progression of secondary caries.

  4. toxicity study in mice of resins of three commiphora species

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT: Acute toxicity studies of crude extracts of resins of Commiphora myrrha, C. guidottii and. C. erlangeriana, and pure compounds isolated from C. erlangeriana were conducted on Swiss albino mice. The extract from C. erlangeriana had a mean LD50 of 410 mg/kg body weight. However the extracts from.

  5. Dammarane triterpenes from the resins of Commiphora confusa

    Directory of Open Access Journals (Sweden)

    Aman Dekebo

    2002-06-01

    Full Text Available The resin of Commiphora confusa afforded two new dammarane triterpenes, (3R,20S-3,20-dihydroxydammar-24-ene and (3R,20S-3-acetoxy-20-hydroxydammar-24-ene along with the known triterpenes, cabraleadiol 3-acetate and α-amyrin.

  6. Three new diterpenoids from the resin of Liquidambar formosana.

    Science.gov (United States)

    Shang, Hong-Jie; Li, Dan-Yi; Wang, Wen-Jing; Li, Zhan-Lin; Hua, Hui-Ming

    2014-01-01

    Three new diterpenoids, liquidambolide A (1) and liquiditerpenoic acids A (2) and B (3), together with 10 known diterpenes were isolated from the resin of Liquidambar formosana Hance, whose structures were elucidated by detailed analysis on the NMR and HR-ESI-MS spectra.

  7. Assessment of polymerization contraction stress of three composite resins

    NARCIS (Netherlands)

    Cadenaro, M.; Biasotto, M.; Scuor, N.; Breschi, L.; Davidson, C.L.; Di Lenarda, R.

    2008-01-01

    Objectives: The purpose of this study was to measure the development of contraction stress of three composite resin restorative materials during photo-polymerization: a micro-hybrid composite (Filtek Z250, 3M ESPE, St. Paul, MN, USA); a nano-filled composite (Filtek Supreme, 3M ESPE, St. Paul, MN,

  8. Synthesis of nanosized barium titanate/epoxy resin composites and ...

    Indian Academy of Sciences (India)

    Anechoic chamber; barium titanate; electromagnetic interference and compatibility; epoxy resin composites; microwave absorbers; radio frequency absorbers. 1. Introduction. Absorption of unwanted microwave energy or electromag- netic interference (EMI) is a pressing problem due to the proliferation of complex high ...

  9. Chemical composition and palaeobotanical origin of Miocene resins ...

    Indian Academy of Sciences (India)

    The terpenoid composition of resins from the Miocene lignite horizons from the Kerala –Konkan Coast,western India was analyzed by Curie-point pyrolysis –gas chromatography –mass spectrometry (Cupy –GC –MS).The major pyrolysates were cadalene-based bicyclic sesquiterpenoids including some C30-C31 ...

  10. Long term stability of cannabis resin and cannabis extracts

    DEFF Research Database (Denmark)

    Lindholst, Christian

    2010-01-01

      The aim of the present study was to investigate the stability of cannabinoids in cannabis resin slabs and cannabis extracts upon long-term storage. The levels of tetrahydrocannabinol (THC), cannabinol (CBN), cannabidiol (CBD) and cannabigerol (CBG) on both neutral and acidic form were measured...

  11. Special Resins for Stereolithography: In Situ Generation of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Gabriele Taormina

    2018-02-01

    Full Text Available The limited availability of materials with special properties represents one of the main limitations to a wider application of polymer-based additive manufacturing technologies. Filled resins are usually not suitable for vat photo-polymerization techniques such as stereolithography (SLA or digital light processing (DLP due to a strong increment of viscosity derived from the presence of rigid particles within the reactive suspension. In the present paper, the possibility to in situ generate silver nanoparticles (AgNPs starting from a homogeneous liquid system containing a well dispersed silver salt, which is subsequently reduced to metallic silver during stereolithographic process, is reported. The simultaneous photo-induced cross-linking of the acrylic resin produces a filled thermoset resin with thermal-mechanical properties significantly enhanced with respect to the unfilled resin, even at very low AgNPs concentrations. With this approach, the use of silver salts having carbon-carbon double bonds, such as silver acrylate and silver methacrylate, allows the formation of a nanocomposite structure in which the release of by-products is minimized due to the active role of all the reactive components in the three dimensional (3D-printing processes. The synergy, between this nano-technology and the geometrical freedom offered by SLA, could open up a wide spectrum of potential applications for such a material, for example in the field of food packaging and medical and healthcare sectors, considering the well-known antimicrobial effects of silver nanoparticles.

  12. Class IV preparation design for microfilled and macrofilled composite resin.

    Science.gov (United States)

    Donly, K J; Browning, R

    1992-01-01

    The current standard preparation for Class IV composite restorations is the placement of a bevel on all enamel margins. This study evaluated chamfered and beveled preparations for Class IV restorations of lesions with microfilled and macrofilled composite resin. Forty incisors were obtained and standardized lesions for Class IV restorations were formed. Twenty teeth had a 1.5-mm bevel placed and 20 had a 1.5-mm chamfered preparation placed. Half of the beveled and chamfered preparations were restored with microfilled composite resin; the remaining were restored with macrofilled composite resin. All restorations were fractured with an Instron Testing Machine. The mean force (lbs +/- SD) to fracture the restorations were: (beveled, microfilled composite 16.0 +/- 4.4); (chamfered, microfilled composite 30.6 +/- 20.0); (beveled, macrofilled composite 34.9 +/- 18.6); (chamfered, macrofilled composite 48.8 +/- 14.3). The chamfered preparations provided greater restoration fracture resistance than beveled preparations, for both microfilled and macrofilled composite restorations. Scheffe's test indicated traditional beveled, microfilled Class IV composite resin restorations significantly decreased fracture resistance compared to chamfered, macrofilled composite restorations (P less than 0.001).

  13. New phenolic esters from the resinous exudate of Haplopappus taeda.

    Science.gov (United States)

    Faini, Francesca; Labbé, Cecilia; Torres, René; Rodilla, Jesús M; Silva, Lucía; Delle Monache, Franco

    2007-12-01

    Two new phenolic esters 9-trans-p-coumaroyloxy-alpha-terpineol (1) and 7-trans-p-coumaroyloxy-taedol (2), both endowed with free radical scavenger activity and cleroda-3,13 (E)-dien-15,18-diol (3) for which a cis stereochemistry at the decalin junction was found, were isolated from the resinous exudate from Haplopappus taeda upper parts.

  14. Recovery of tetrachloroaurate through ion exchange with Dowex 11 resin

    Directory of Open Access Journals (Sweden)

    Alguacil, F. J.

    1998-05-01

    Full Text Available The recovery of the tetrachloroaurate complex by the anionic ion exchange resin Dowex 11 has been studied. The kinetics of gold adsorption were dependent of both gold and resin concentrations and temperature. The adsorption isotherm can be described by the expression Q = kCn. The loaded resin could be eluted by an acidic thiourea solution at 20°C. After several adsorption-elution cycles there is not any apparent loss in the adsorption properties of the resin.

    Se estudia la recuperación del ion tetracloroaurato mediante la resina aniónica Dowex 11. La extracción de oro depende tanto de las concentraciones del metal y la resina como de la temperatura. La isoterma de adsorción responde a la ecuación Q = kCn. La resina cargada con oro puede ser eluida con una disolución acida de tiourea a 20°C. Después de varios ciclos de adsorción-desorción no hay pérdida de carga por parte de la resina.

  15. Resin collection and social immunity in honey bees.

    Science.gov (United States)

    Simone, Michael; Evans, Jay D; Spivak, Marla

    2009-11-01

    Diverse animals have evolved an ability to collect antimicrobial compounds from the environment as a means of reducing infection risk. Honey bees battle an extensive assemblage of pathogens with both individual and "social" defenses. We determined if the collection of resins, complex plant secretions with diverse antimicrobial properties, acts as a colony-level immune defense by honey bees. Exposure to extracts from two sources of honey bee propolis (a mixture of resins and wax) led to a significantly lowered expression of two honey bee immune-related genes (hymenoptaecin and AmEater in Brazilian and Minnesota propolis, respectively) and to lowered bacterial loads in the Minnesota (MN) propolis treated colonies. Differences in immune expression were also found across age groups (third-instar larvae, 1-day-old and 7-day-old adults) irrespective of resin treatment. The finding that resins within the nest decrease investment in immune function of 7-day-old bees may have implications for colony health and productivity. This is the first direct evidence that the honey bee nest environment affects immune-gene expression.

  16. Bond strength of resin composite to differently conditioned amalgam

    NARCIS (Netherlands)

    Ozcan, M; Vallittu, PK; Huysmans, MC; Kalk, W; Vahlberg, T

    Bulk fracture of teeth, where a part of the amalgam restoration and/or the cusp is fractured, is a common clinical problem. The aim of this study was to evaluate the effect of different surface conditioning methods on the shear bond strength of a hybrid resin composite to fresh amalgam. Amalgams (N

  17. The Translucency Effect of Different Colored Resin Cements used ...

    African Journals Online (AJOL)

    Purpose: The purpose of this study was to evaluate the effect of the different color of resin cements and zirconia cores on the translucency parameter (TP) of the restoration that simulates the implant‑supported fixed prosthesis using titanium base on the bottom. Materials and Methods: Zirconia core plates (Zr‑Zahn) were ...

  18. 21 CFR 872.3300 - Hydrophilic resin coating for dentures.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydrophilic resin coating for dentures. 872.3300 Section 872.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... into the patient's mouth to improve denture retention and comfort. (b) Classification. Class II. ...

  19. Repair of Defective Composite Resin Restoration: Current Trend ...

    African Journals Online (AJOL)

    Background: Repair of defective composite resins restorations is being increasingly recognized as a viable alternative to replacement. there is however no consensus yet on the treatment protocol. Objective: To determine the views and practice of specialists in Conservative Dentistry in Nigeria as regard to repair procedure ...

  20. Terpenoids of Boswellia neglecta oleo-gum resin

    OpenAIRE

    L. O. A. Manguro; S. O.Wagai; J. O. Onyango

    2016-01-01

    Oleo-gum resin exudate from Boswellia neglecta afforded a new ursane-type triterpene characterized as 3α-acetoxy-28-hydroxy-11-oxours-12-en-24-ioc acid (1) together with twelve known compounds. Their structural elucidation was accomplished using physical, chemical and spectroscopic methods.

  1. Terpenoids of Boswellia neglecta oleo-gum resin

    Directory of Open Access Journals (Sweden)

    L. O. A. Manguro

    2016-08-01

    Full Text Available Oleo-gum resin exudate from Boswellia neglecta afforded a new ursane-type triterpene characterized as 3α-acetoxy-28-hydroxy-11-oxours-12-en-24-ioc acid (1 together with twelve known compounds. Their structural elucidation was accomplished using physical, chemical and spectroscopic methods.

  2. characterisation of rapeseed oil based resins using infrared

    African Journals Online (AJOL)

    Mgina

    ABSTRACT. Rapeseed oil which is a triglyceride had undergone chemical modification on its structure to obtain hydroxyl groups. The hydroxylated chemical structure was crosslinked using methylene-p- phenyl diisocyanate to produce a thermoset rapeseed oil resin. The cross linking process was monitored in situ using ...

  3. The study of epoxy polyamide and polyvinyl resins as corrosion ...

    African Journals Online (AJOL)

    The corrosion resistance of two commonly used protective coatings (epoxy polyamide and polyvinyl resins) in the Niger Delta area of Nigeria has been assessed. The coatings on low carbon steel were subjected to varying conditions of pH, temperature and exposure time and the corrosion rates calculated. At a pH of 2, 3, 4, ...

  4. 21 CFR 177.1600 - Polyethylene resins, carboxyl modified.

    Science.gov (United States)

    2010-04-01

    ... following substances: Ammonium hydroxide. Calcium carbonate. Potassium hydroxide. Sodium hydroxide. (b) The... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1600 Polyethylene resins...

  5. Solubilities of sub- and supercritical carbon dioxide in polyester resins

    NARCIS (Netherlands)

    Nalawade, SP; Picchioni, F; Janssen, LPBM; Patil, VE; Keurentjes, JTF; Staudt, R; Nalawade, Sameer P.; Patil, Vishal E.; Keurentjes, Jos T.F.

    In supercritical carbon dioxide (CO2) assisted polymer processes the solubility of CO2 in a polymer plays a vital role. The higher the amount of CO2 dissolved in a polymer the higher is the viscosity reduction of the polymer. Solubilities Of CO2 in polyester resins based on propoxylated bisphenol

  6. Silicone Resin Applications for Ceramic Precursors and Composites

    Directory of Open Access Journals (Sweden)

    Masaki Narisawa

    2010-06-01

    Full Text Available This article reviews the applications of silicone resins as ceramic precursors. The historical background of silicone synthesis chemistry is introduced to explain the production costs and supply availability of various silicones. Thermal degradation processes of silicones are classified in terms of the main chain structure and cyclic oligomer expulsion process, which determine the resulting ceramic yield and the chemical composition. The high temperature decomposition of Si-O-C beyond 1,400 °C in an inert atmosphere and formation of a protective silica layer on material surfaces beyond 1,200 °C in an oxidative atmosphere are discussed from the viewpoints of the wide chemical composition of the Si-O-C materials. Applications of the resins for binding agents, as starting materials for porous ceramics, matrix sources with impregnation, fiber spinning and ceramic adhesions are introduced. The recent development of the process of filler or cross-linking agent additions to resin compounds is also introduced. Such resin compounds are useful for obtaining thick coatings, MEMS parts and bulk ceramics, which are difficult to obtain by pyrolysis of simple organometallic precursors without additives.

  7. Potential application of resin extracts of Anogeissus leiocarpus plant ...

    African Journals Online (AJOL)

    The ploy condensation of tannin with formaldehyde produced a thermosetting resin with useful properties; formaldehyde (10.5 ml), tannin (2.5 g), glycerol (0.6 ml), hexamine (5.5 g), pH ... Absorption behaviour of the films from the thermosetting material formulated under aqueous, acid and basic conditions were investigated.

  8. Toxicity study in mice of resins of three Commiphora species ...

    African Journals Online (AJOL)

    Acute toxicity studies of crude extracts of resins of Commiphora myrrha, C. guidottii and C. erlangeriana, and pure compounds isolated from C. erlangeriana were conducted on Swiss albino mice. The extract from C. erlangeriana had a mean LD50 of 410 mg/kg body weight. However the extracts from C. myrrha and C.

  9. Assessment of Service Life for Regenerative ECLSS Resin Beds

    Science.gov (United States)

    Cloud, Dale L.; Keilich, Maria C.; Polis, Peter C.; Yanczura, Stephen J.

    2013-01-01

    The International Space Station (ISS) Water Processor Assembly (WPA) and Oxygen Generation Assembly (OGA) manage and process water at various levels of cleanliness for multiple purposes. The effluent of theWPA and the influent of the OGA require water at very high levels of purity. The bulk of the water purification that occurs in both systems is performed by consumable activated carbon and ion exchange resin beds. Replacement beds must be available on orbit in order to continue the ISS critical processes of water purification and oxygen generation. Various hurdles exist in order to ensure viable spare resin beds. These include the characteristics of resin beds such as: storage environment, shelf life requirements, microbial growth, and variations in the levels and species of contaminants the beds are required to remove. Careful consideration has been given to match water models, bed capacities and spares traffic models to ensure that spares are always viable. The results of these studies and considerations, in particular, how shelf life requirements affect resin bed life management, are documented in this paper.

  10. Effect of resin extract from Commiphora swynnertonii (Burseraceae ...

    African Journals Online (AJOL)

    The biological activities of various Commiphora plants (Burseraceae) have progressively been studied over a decade. Recent studies have established the ethnomedicinal potency of various Commiphora species in Africa and Asia. In this study, the effect of Commiphora swynnertonii resin on biochemical parameters in rats ...

  11. Positron Annihilation in a Rubber Modified Epoxy Resin

    DEFF Research Database (Denmark)

    Mogensen, O. E.; Jacobsen, F. M.; Pethrick, R. A.

    1979-01-01

    Positron annihilation data is reported on a rubber-modified epoxy resin. Studies of the temperature dependence of the o-positronium lifetime indicated the existence of three distinct regions; the associated transition temperatures by comparison with dilatometric data can be ascribed respectively...

  12. Triterpenes from the resin of Boswellia neglecta | Dekebo | Bulletin ...

    African Journals Online (AJOL)

    2002-03-13

    The resin of Boswellia neglecta yielded four triterpenes canaric acid, a -amyrin, a -amyrone and epi-a -amyrin. Canaric acid and epi-a -amyrin are isolated here for the first time from the family Burseraceae. The compounds were identified using 1D and 2D NMR techniques. (Received March 13, 2002; revised May 17, 2002)

  13. Impact fatigue behaviour of carbon fibre-reinforced vinylester resin ...

    Indian Academy of Sciences (India)

    Two types of unidirectional carbon fibre, one of high strength (DHMS) and another of medium strength (VLMS) reinforced vinylester resin composites have been examined for their impact fatigue behaviour over 104 impact cycles for the first time. The study was conducted using a pendulum type repeated impact apparatus ...

  14. The Fracture of Thermosetting Resins after Exposure to Water.

    Science.gov (United States)

    1980-09-01

    1.0 water. 23 0C uptakeamine-cured 0.6 /* anhydride cured 0.2 bisphenol cured epoxy/glass laminate (VF =0.55) Source: H W Gitschner and G Menges...process, pipe and food storage applications. Like epoxides, these resins withstand water well, except at higher temperatures. The reason for their

  15. 21 CFR 520.1242d - Levamisole resinate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Levamisole resinate. 520.1242d Section 520.1242d Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... (Ascaris suum), nodular worms (Oesophagostomum spp.), lungworms (Metastrongylus spp.), intestinal...

  16. Composite Resin – A Versatile Restorative Tool | Koleoso | Nigerian ...

    African Journals Online (AJOL)

    Objectives: The study was carried out to demonstrate the use of composite resin restorations as a treatment option in several situations where conventional aesthetic restorations such as porcelain veneers, crowns ... Keywords: Dental aesthetic, Composite crowns, composite veneers, Composite filling, Adhesive dentistry.

  17. Resin bonded bridgework in a public health service | Olorunfemi ...

    African Journals Online (AJOL)

    Objectives: To investigate some of the clinical variables that may affect the longevity of the resin bonded fixed partial denture [RBFPD] in a public health care facility. Method: A retro-prospective clinical review of patients and records to evaluate the clinical factors that may predispose to failure of RBFPDs placed in the Assir ...

  18. Developing a New Generation of Antimicrobial and Bioactive Dental Resins.

    Science.gov (United States)

    Cheng, L; Zhang, K; Zhang, N; Melo, M A S; Weir, M D; Zhou, X D; Bai, Y X; Reynolds, M A; Xu, H H K

    2017-07-01

    Dental caries is prevalent, and secondary caries causes restoration failures. This article reviews recent studies on developing a new generation of bioactive resins with anticaries properties. Extensive effects were made to develop new antimicrobial composites, bonding agents, and other resins containing quaternary ammonium methacrylates to suppress plaque buildup and bacterial acid production. The effects of alkyl chain length and charge density and the antimicrobial mechanisms for chlorhexidine, nano-silver, quaternary ammonium methacrylates, and protein-repellent agents were discussed. Synergistic effects of contact-killing and protein-repellent properties were shown to yield the greatest biofilm-inhibition effects. The combination of antimicrobial, protein-repellent, and calcium phosphate nanoparticle remineralization was suggested to provide maximal anticaries effects. In addition, for use orally, cytotoxicity and biocompatibility were important considerations for the new bioactive materials. Furthermore, rather than kill all bacteria, it would be more desirable to modulate the oral biofilm compositions via bioactive resins to suppress cariogenic/pathogenic species and promote benign species. For widespread clinical use of the new antimicrobial and therapeutic materials, whether they would induce bacterial drug resistance needs to be determined, which requires further study. Nonetheless, the new generation of bioactive anticaries resins with therapeutic and biofilm acid-inhibiting properties has the potential to substantially benefit oral health.

  19. Degradation of dental resin composites during intra-oral wear

    NARCIS (Netherlands)

    Yulianto, Heribertus Dedy Kusuma

    2017-01-01

    Dental resin composites have become an integral part of modern dentistry and used worldwide to restore missing tooth structures, to modify tooth color and anatomical contour, and to enhance aesthetics and function. The dentist should be aware that, the aggressive complexity of the oral environment

  20. The Translucency Effect of Different Colored Resin Cements used ...

    African Journals Online (AJOL)

    2018-01-30

    Jan 30, 2018 ... Purpose: The purpose of this study was to evaluate the effect of the different color of resin cements and zirconia cores on the translucency parameter (TP) of the restoration that simulates the implant‑supported fixed prosthesis using titanium base on the bottom. Materials and Methods: Zirconia core plates ...

  1. Facile synthesis of allyl resinate monomer in an aqueous solution ...

    Indian Academy of Sciences (India)

    Keywords. Allyl resinate; microwave energy; rosin-derivatives; phase transfer catalysis. 1. Introduction. In recent years, there has been an increasing inter- est in the synthesis of environmental protection chem- icals using renewable resources such as rosin. Fossil resources can be substituted by renewable resources in.

  2. Studies on blends of cycloaliphatic epoxy resin with varying ...

    Indian Academy of Sciences (India)

    Differential scanning calorimetric (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) of the blends of cycloaliphatic epoxy (CAE) resin toughened with liquid elastomer such as carboxyl terminated butadiene acrylonitrile copolymer (CTBN) have been carried out. Exothermal heat of reaction ...

  3. Characterisation of Rapeseed Oil Based Resins Using Infrared and ...

    African Journals Online (AJOL)

    Rapeseed oil which is a triglyceride had undergone chemical modification on its structure to obtain hydroxyl groups. The hydroxylated chemical structure was crosslinked using methylene-pphenyl diisocyanate to produce a thermoset rapeseed oil resin. The cross linking process was monitored in situ using the Attenuated ...

  4. ESSENTIAL OILS OF RESINS FROM THREE PIN US SPECIES

    African Journals Online (AJOL)

    ABSTRACT: The chemical composition of the hydro-distillates obtained from resins of Pinus caribaea, P. radiata and P. patula growing in Ethiopia and P. caribaea from Uganda, were investigated by GC and GC-MS. Twenty compounds were identified representing ca 92-99% of the total oil. The only major constituent of P.

  5. Development of 3-methoxy-4-benzyloxybenzyl alcohol (MBBA) resin ...

    Indian Academy of Sciences (India)

    Administrator

    solid supports in many critical ways.2 The solid sup- ports used most widely in SPOS are Merrifield resin and their ... immobilized protecting groups since many of them bear some similarities to protecting groups in solu- ..... Long Q, Shi M X and Zheng B-Z 2005 Chin. J. Funct. Polym. 18 32. 12. (a) Porco J A, Deedan T, ...

  6. Study on Concrete Containing Recycled Aggregates Immersed in Epoxy Resin

    Directory of Open Access Journals (Sweden)

    Adnan Suraya Hani

    2017-01-01

    Full Text Available In recent decades, engineers have sought a more sustainable method to dispose of concrete construction and demolition waste. One solution is to crush this waste concrete into a usable gradation for new concrete mixes. This not only reduces the amount of waste entering landfills but also alleviates the burden on existing sources of quality natural concrete aggregates. There are too many kinds of waste but here constructions waste will be the priority target that should be solved. It could be managed by several ways such as recycling and reusing the concrete components, and the best choice of these components is the aggregate, because of the ease process of recycle it. In addition, recycled aggregates and normal aggregates were immersed in epoxy resin and put in concrete mixtures with 0%, 5%, 10% and 20% which affected the concrete mixtures properties. The strength of the concrete for both normal and recycled aggregates has increased after immersed the aggregates in epoxy resin. The percentage of water absorption and the coefficient of water permeability decreased with the increasing of the normal and the recycled aggregates immersed in epoxy resin. Generally the tests which have been conducted to the concrete mixtures have a significant results after using the epoxy resin with both normal and recycled aggregates.

  7. Amalgam stained dentin: a proper substrate for bonding resin composite?

    NARCIS (Netherlands)

    Scholtanus, J.D.

    2016-01-01

    Nowadays the use of dental amalgam is mostly abandoned and substituted by tooth colored resin composites that can be bonded to teeth tissues by adhesive techniques. The aim of this thesis was to find out whether dark stained dentin, as often observed after removal of amalgam restorations and

  8. Photothermal radiometry monitoring of light curing in resins

    Energy Technology Data Exchange (ETDEWEB)

    Zambrano-Arjona, M A [Applied Physics Department, Cinvestav-Unidad Merida, A.P. 73 Cordemex, Merida, 97310 (Mexico); Medina-Esquivel, R [Cinvestav-Unidad Queretaro, Libramiento Norponiente 2000 Fracc. Real de Juriquilla, CP 76230, Queretaro (Mexico); Alvarado-Gil, J J [Applied Physics Department, Cinvestav-Unidad Merida, A.P. 73 Cordemex, Merida, 97310 (Mexico)

    2007-10-07

    Real time measurement of thermal diffusivity during the evolution of the light curing process in dental resins is reported using photothermal radiometry. The curing is induced by a non-modulated blue light beam, and at the same time, a modulated red laser beam is sent onto the sample, generating a train of thermal waves that produce modulated infrared radiation. The monitoring of this radiation permits to follow the time evolution of the process. The methodology is applied to two different commercially available light curing resin-based composites. In all cases thermal diffusivity follows a first order kinetics with similar stabilization characteristic times. Analysis of this kinetics permits to exhibit the close relationship of increase in thermal diffusivity with the decrease in monomer concentration and extension of the polymerization in the resin, induced by the curing light. It is also shown that the configuration in which the resin is illuminated by the modulated laser can be the basis for the development of an in situ technique for the determination of the degree of curing.

  9. Textile impregnation with thermoplastic resin - models and application

    NARCIS (Netherlands)

    Loendersloot, Richard; Grouve, Wouter Johannes Bernardus; Lamers, E.A.D.; Wijskamp, Sebastiaan; Kelly, P.A.; Bickerton, S.; Lescher, P.; Govignon, Q.

    2012-01-01

    One of the key issues of the development of cost-effective thermoplastic composites for the aerospace industry is the process quality control. A complete, void free impregnation of the textile reinforcement by the thermoplastic resin is an important measure of the quality of composites. The

  10. Gingival Tissue Color Related With Facial Skin and Acrylic Resin ...

    African Journals Online (AJOL)

    Research into the degree of epithelial vascularisation, keratinisation and melanin pigmentation of the various zones in the mouth in this environment is required which may explain the reason for the dark colour observed in the attached gingival. Key Word: Gingival tissue colour, denture, skin, acrylic resin, Nigerians ...

  11. Microhardness of heat cure acrylic resin after treatment with disinfectants.

    Science.gov (United States)

    Amin, Faiza; Rehman, Abdur; Abbas, Muhammad

    2015-08-01

    To evaluate the effect of disinfectants and distilled water on the micro-hardness of heat cure acrylic resins. The case-control study was conducted at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, and Nadirshaw Edulji Dinshaw University of Engineering and Technology, Karachi, from April to October 2011. Specimens were fabricated from heat cure acrylic resin material and they were divided into four equal groups. Group 1 was evaluated at baseline and was taken as the control group. Group 2 was immersed in distilled water for 20 minutes, Group 3 in1% sodium hypochlorite for 20 minutes, and Group 4 in 2% alkaline gluteraldehyde for 10 minutes. All specimens were polished, stored in distilled water for 24 hours prior to experiment. All the specimens were immersed twice daily for a total of 60 days after which they were tested for Vickers micro-hardness test. Statistical analysis was conducted with one-way analysis of variance and Tukey post hoc test (a=0.05). There were 72 specimens divided into four groups of 18(25%) each. Statistically significant differences were found among all groups (pacrylic resins. Group 4 showed the most reduction in the hardness value which was followed by Group 3. The hardness of heat cure acrylic resin was affected by disinfectants.

  12. characterisation of rapeseed oil based resins using infrared

    African Journals Online (AJOL)

    Mgina

    CHARACTERISATION OF RAPESEED OIL BASED RESINS. USING INFRARED AND THERMOGRAVIMETRY TECHNIQUES. LY Mwaikambo. Department of Mechanical and Industrial Engineering,. University of Dar Es salaam, P.O. Box 35131, Dar Es salaam, Tanzania, lyrmwaikambo@udsm.ac.tz. ABSTRACT. Rapeseed ...

  13. Coating glass-ionomer cements with a nanofilled resin

    NARCIS (Netherlands)

    Bonifacio, C.C.; Werner, A.; Kleverlaan, C.J.

    2012-01-01

    Objectives. The objective of this study was to investigate the effect of a nanofilled resin coat on the flexural strength (FS) and the early wear (after 50 000 and 200 000 cycles) of the glass-ionomer cements Fuji IX GP Extra (FIXE) and Ketac Molar Aplicap (KM). Materials and methods. Specimens were

  14. Bond strength between acrylic resin and maxillofacial silicone

    Science.gov (United States)

    HADDAD, Marcela Filié; GOIATO, Marcelo Coelho; dos SANTOS, Daniela Micheline; CREPALDI, Nádia de Marchi; PESQUEIRA, Aldiéris Alves; BANNWART, Lisiane Cristina

    2012-01-01

    The development of implant dentistry improved the possibilities of rehabilitation with maxillofacial prosthesis. However, clinically it is difficult to bond the silicone to the attachment system. Objectives This study aimed to evaluate the effect of an adhesive system on the bond strength between acrylic resin and facial silicone. Material and Methods A total of 120 samples were fabricated with auto-polymerized acrylic resin and MDX 4-4210 facial silicone. Both materials were bonded through mechanical retentions and/or application of primers (DC 1205 primer and Sofreliner primer S) and adhesive (Silastic Medical Adhesive Type A) or not (control group). Samples were divided into 12 groups according to the method used to attach the silicone to the acrylic resin. All samples were subjected to a T-peel test in a universal testing machine. Failures were classified as adhesive, cohesive or mixed. The data were evaluated by the analysis of variance (ANOVA) and the Tukey's HSD test (α=.05). Results The highest bond strength values (5.95 N/mm; 3.07 N/mm; 4.75 N/mm) were recorded for the samples that received a Sofreliner primer application. These values were significantly higher when the samples had no scratches and did not receive the application of Silastic Medical Adhesive Type A. Conclusions The most common type of failure was adhesive. The use of Sofreliner primer increased the bond strength between the auto-polymerized acrylic resin and the Silastic MDX 4-4210 facial silicone. PMID:23329247

  15. Development of amino resins for emulsion paint formulation: effect of ...

    African Journals Online (AJOL)

    The viscosity, gel time, density and refractive index of the resins (except UB) were found to increase with increase in alkyl length of the aldehydic group while turbidity (except UF) increased with increase in alkyl length of the aldehydic group. On the other hand, melting point and moisture uptake decreases with increase in ...

  16. Epoxy resin monomers with reduced skin sensitizing potency.

    Science.gov (United States)

    O'Boyle, Niamh M; Niklasson, Ida B; Tehrani-Bagha, Ali R; Delaine, Tamara; Holmberg, Krister; Luthman, Kristina; Karlberg, Ann-Therese

    2014-06-16

    Epoxy resin monomers (ERMs), especially diglycidyl ethers of bisphenol A and F (DGEBA and DGEBF), are extensively used as building blocks for thermosetting polymers. However, they are known to commonly cause skin allergy. This research describes a number of alternative ERMs, designed with the aim of reducing the skin sensitizing potency while maintaining the ability to form thermosetting polymers. The compounds were designed, synthesized, and assessed for sensitizing potency using the in vivo murine local lymph node assay (LLNA). All six epoxy resin monomers had decreased sensitizing potencies compared to those of DGEBA and DGEBF. With respect to the LLNA EC3 value, the best of the alternative monomers had a value approximately 2.5 times higher than those of DGEBA and DGEBF. The diepoxides were reacted with triethylenetetramine, and the polymers formed were tested for technical applicability using thermogravimetric analysis and differential scanning calorimetry. Four out of the six alternative ERMs gave polymers with a thermal stability comparable to that obtained with DGEBA and DGEBF. The use of improved epoxy resin monomers with less skin sensitizing effects is a direct way to tackle the problem of contact allergy to epoxy resin systems, particularly in occupational settings, resulting in a reduction in the incidence of allergic contact dermatitis.

  17. Mechanisms of Interactions of Energetic Electrons with Epoxy Resins

    Science.gov (United States)

    Gupta, A.; Coulter, D. R.; Tsay, F. D.; Moacanin, J.

    1982-01-01

    The mechanism of deactivation of energy of excitation in a resin system was investigated on optical excitation as well as excitation by high energy electrons. This mechanism involves formation of excited state complexes, known as exciplexes which have a considerable charge transfer character. This mechanism will be used to develop a degradation model for epoxy matrix materials deployed in a space environment.

  18. Radiopacity of bulk fill flowable resin composite materials

    African Journals Online (AJOL)

    2015-08-23

    Aug 23, 2015 ... selected by avoiding areas containing air bubbles inside the material. This procedure was repeated 5 times for each specimen and aluminum stepwedge, and the .... Financial support and sponsorship. Nil. Conflicts of interest. There are no conflicts of interest. References. 1. Ferracane JL. Resin composite ...

  19. Resin infiltration of proximal caries lesions differing in ICDAS codes.

    Science.gov (United States)

    Paris, Sebastian; Bitter, Kerstin; Naumann, Michael; Dörfer, Christof E; Meyer-Lueckel, Hendrik

    2011-04-01

    Resin infiltration of non-cavitated proximal caries lesions has been shown to inhibit further demineralization. However, the effect of resin infiltration in cavitated lesions is unknown. Therefore, the aim of this in vitro study was to evaluate infiltration patterns of proximal caries lesions differing in International Caries Detection and Assessment System (ICDAS) codes. Extracted human molars and premolars showing proximal caries lesions with and without cavitations (ICDAS codes 2-5) were etched with 15% hydrochloric acid gel and resin infiltrated according to the manufacturer's instructions. Three sections from each lesion were prepared and analyzed using a dual-fluorescence staining technique and confocal microscopy. The dimensions of the demineralized and cavitated lesions areas, as well as the resin-infiltrated parts within these lesions, were measured. The demineralized parts were infiltrated from 73% to 100% (median values) but the cavities were filled only negligibly (0-5%). Teeth that had an ICDAS code of 5 showed a significantly lower percentage infiltration/filling of lesions compared to teeth with ICDAS codes of 2 and 3. It was concluded that under in vitro conditions the tested infiltrant penetrates most parts of the demineralized enamel but is not capable of filling up cavities and therefore the efficacy of caries infiltration, particularly in lesions with larger cavitations, might be impaired. © 2011 Eur J Oral Sci.

  20. Cost benefit of patch testing with textile finish resins

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Hamann, K

    1982-01-01

    Eleven years experience of textile finish resin patch testing of suspected textile dermatitis patients revealed 15 cases of allergic textile dermatitis among 428 patients tested. Ten of the 15 patients had a relevant positive patch test to one or more of a limited series of textile finishes; 1 wa...

  1. Constituents from the bark resin of Schinus molle

    OpenAIRE

    Malca-García,Gonzalo Rodolfo; Hennig, Lothar; Ganoza-Yupanqui,Mayar Luis; Piña-Iturbe,Alejandro; Rainer W. Bussmann

    2017-01-01

    ABSTRACT A total of five terpenes was isolated from the bark resin of Schinus molle L., Anacardiaceae, and their structures were determined by spectroscopic techniques. Among these compounds the sesquiterpene hydrocarbon terebinthene showed significant growth inhibitory activity against human colon carcinoma HCT-116 cells. Furthermore, terebinthene and pinicolic acid (5) also showed antibacterial activity against Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633.

  2. The effects of desensitizing resin, resin sealing, and provisional cement on the bond strength of dentin luted with self-adhesive and conventional resincements.

    Science.gov (United States)

    Sailer, Irena; Oendra, Andrea E Hernandez; Stawarczyk, Bogna; Hämmerle, Christoph H F

    2012-04-01

    Self-adhesive resin cements were designed to bond without any pretreatment of dentin. However, pretreatments such as the application of desensitizing resin or the resin sealing of dentin with priming/bonding solutions might influence the bonding quality of these self-adhesive resin cements. Little is known about the effect of dentin pretreatment on the bond quality of self-adhesive resin cements. This study evaluated whether dentin desensitizing or sealing methods influenced the shear bond strength of 1 self-adhesive and 2 conventional resin cements. One-hundred and eighty human molars were assigned to 5 different pretreatment groups: 1) freshly ground dentin, 2) glutaraldehyde/hydroxyethylmethacrylate (HEMA) desensitized dentin (Gluma), 3) contamination of desensitized dentin with provisional cement, 4) sealed dentin (dual bonding technique), and 5) contamination of sealed dentin with provisional cement. The shear bond strength of a self-adhesive resin cement (RelyX Unicem; RXU) and 2 conventional resin cements (Variolink II; VAR, Panavia 21; PAN) was assessed for each pretreatment group (n=12 per cement types). Two-way ANOVA and 1-way ANOVA together with the post hoc Tukey multiple comparison (α=.05) were performed. On freshly ground dentin, PAN exhibited the highest shear bond strength values (Pdentin (Pdentin increased the bond strength of RXU but had no significant effect on VAR or PAN. RXU exhibited the highest mean bond strength after the contamination of resin-sealed dentin by provisional cement. Glutaraldehyde/HEMA treatment and resin sealing of dentin have a beneficial effect on the shear bond strength of self-adhesive resin cement (RXU). Contamination of dentin with provisional cement has no influence on the bond strength of the self-adhesive resin cement (RXU) or VAR but lowered the bond strength of PAN. Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  3. Study on binder system of CO2-cured phenol-formaldehyde resin used in phenol-formaldehyde resin used in foundry

    OpenAIRE

    Liu Weihua; Li Yingmin; Qu Xueliang

    2008-01-01

    A new aqueous alkaline resol phenol-formaldehyde resin has been prepared from phenol and formaldehyde using NaOH as catalyst; the optimum synthetic process has been determined. With addition of some cross-linking agents, after passing carbon dioxide gas through the resin bonded sand, high as-gassed strength and 24 h strength are achieved. The bonding bridge of the resin bonded sand fracture has been analyzed by using SEM.

  4. Pyroacm Resin: An Acetamidomethyl Derived Resin for Solid Phase Synthesis of Peptides through Side Chain Anchoring of C-Terminal Cysteine Residues.

    Science.gov (United States)

    Juvekar, Vinayak; Gong, Young Dae

    2016-02-19

    The design, synthesis and utilization of an efficient acetamidomethyl derived resin for the peptide synthesis is presented using established Fmoc and Boc protocols via side chain anchoring. Cleavage of the target peptide from the resin is performed using carboxymethylsulfenyl chloride under mild conditions which gave in situ thiol-sulfenyl protection of the cysteine residues. The utility of the resin is successfully demonstrated through applications to the syntheses of model peptides and natural products Riparin 1.1 and Riparin 1.2.

  5. Shear bond strength of computer-aided design and computer-aided manufacturing feldspathic and nano resin ceramics blocks cemented with three different generations of resin cement

    OpenAIRE

    Zuryati Ab-Ghani; Wahyuni Jaafar; Siew Fon Foo; Zaihan Ariffin; Dasmawati Mohamad

    2015-01-01

    Aim: To evaluate the shear bond strength between the dentin substrate and computer-aided design and computer-aided manufacturing feldspathic ceramic and nano resin ceramics blocks cemented with resin cement. Materials and Methods: Sixty cuboidal blocks (5 mm × 5 mm × 5 mm) were fabricated in equal numbers from feldspathic ceramic CEREC ® Blocs PC and nano resin ceramic Lava™ Ultimate, and randomly divided into six groups (n = 10). Each block was cemented to the dentin of 60 extracted huma...

  6. Cation immobilization in pyrolyzed simulated spent ion exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Luca, Vittorio, E-mail: vluca@cnea.gov.ar [Programa Nacional de Gestion de Residuos Radiactivos, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina); Bianchi, Hugo L. [Gerencia de Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina); ECyT, Universidad Nacional de General San Martin, Campus Miguelete, Ed. Tornavias, Martin de Irigoyen 3100, 1650 San Martin (Argentina); Conicet, Av. Rivadavia 1917, 1033 Buenos Aires (Argentina); Manzini, Alberto C. [Programa Nacional de Gestion de Residuos Radiactivos, Comision Nacional de Energia Atomica, Av. Del Libertador 8250, CP 1429, Ciudad Autonoma de Buenos Aires (Argentina)

    2012-05-15

    Significant quantities of spent ion exchange resins that are contaminated by an assortment of radioactive elements are produced by the nuclear industry each year. The baseline technology for the conditioning of these spent resins is encapsulation in ordinary Portland cement which has various shortcomings none the least of which is the relatively low loading of resin in the cement and the poor immobilization of highly mobile elements such as cesium. The present study was conducted with cationic resin samples (Lewatit S100) loaded with Cs{sup +}, Sr{sup 2+}, Co{sup 2+}, Ni{sup 2+} in roughly equimolar proportions at levels at or below 30% of the total cation exchange capacity. Low temperature thermal treatment of the resins was conducted in inert (Ar), or reducing (CH{sub 4}) gas atmospheres, or supercritical ethanol to convert the hydrated polymeric resin beads into carbonaceous materials that contained no water. This pyrolytic treatment resulted in at least a 50% volume reduction to give mechanically robust spherical materials. Scanning electron microscope investigations of cross-sections of the beads combined with energy dispersive analysis showed that initially all elements were uniformly distributed through the resin matrix but that at higher temperatures the distribution of Cs became inhomogeneous. Although Cs was found in the entire cross-section, a significant proportion of the Cs occurred within internal rings while a proportion migrated toward the outer surfaces to form a crustal deposit. Leaching experiments conducted in water at 25 Degree-Sign C showed that the divalent contaminant elements were very difficult to leach from the beads heated in inert atmospheres in the range 200-600 Degree-Sign C. Cumulative fractional loses of the order of 0.001 were observed for these divalent elements for temperatures below 500 Degree-Sign C. Regardless of the processing temperature, the cumulative fractional loss of Cs in water at 25 Degree-Sign C reached a plateau or

  7. Nonlinear Inelastic Mechanical Behavior Of Epoxy Resin Polymeric Materials

    Science.gov (United States)

    Yekani Fard, Masoud

    Polymer and polymer matrix composites (PMCs) materials are being used extensively in different civil and mechanical engineering applications. The behavior of the epoxy resin polymers under different types of loading conditions has to be understood before the mechanical behavior of Polymer Matrix Composites (PMCs) can be accurately predicted. In many structural applications, PMC structures are subjected to large flexural loadings, examples include repair of structures against earthquake and engine fan cases. Therefore it is important to characterize and model the flexural mechanical behavior of epoxy resin materials. In this thesis, a comprehensive research effort was undertaken combining experiments and theoretical modeling to investigate the mechanical behavior of epoxy resins subject to different loading conditions. Epoxy resin E 863 was tested at different strain rates. Samples with dog-bone geometry were used in the tension tests. Small sized cubic, prismatic, and cylindrical samples were used in compression tests. Flexural tests were conducted on samples with different sizes and loading conditions. Strains were measured using the digital image correlation (DIC) technique, extensometers, strain gauges, and actuators. Effects of triaxiality state of stress were studied. Cubic, prismatic, and cylindrical compression samples undergo stress drop at yield, but it was found that only cubic samples experience strain hardening before failure. Characteristic points of tensile and compressive stress strain relation and load deflection curve in flexure were measured and their variations with strain rate studied. Two different stress strain models were used to investigate the effect of out-of-plane loading on the uniaxial stress strain response of the epoxy resin material. The first model is a strain softening with plastic flow for tension and compression. The influence of softening localization on material behavior was investigated using the DIC system. It was found that

  8. Film thickness of resin cements used with adhesive systems.

    Science.gov (United States)

    Zahra, Vivian N; Abate, Pablo F; Macchi, Ricardo L

    2008-01-01

    The final film thickness of a resin adhesive and a resin cement could be affected by previous polymerization of the adhesive systems on dentin surfaces. The aim of this work was to evaluate changes in the film thickness of dual resin based cements with their adhesives as a function of polymerization of the latter on dentin surfaces. The materials used were: RelyX ARC (R) + Single Bond (SB) and Variolink base (VB) and high (HV) or low (LV) viscosity catalyst + Syntac Classic (S) or Excite DSC (E); 56 human dentin discs and 56 composite resin discs (Z250). Dentin disc surfaces were treated with 35% phosphoric acid (except for S) and the adhesive system was either polymerized or not polymerized. A 0.05 ml increment of cement mixture was placed on the dentin disc and covered with the resin disc. A 25 N load was applied for ten minutes and then, the combined thickness was measured with a digital micrometer. Sample size (n) was 4 for each cement or condition. A two-way analysis of variance was performed with a level of significance of p adhesive layer, were: R+SB: 16.50 (2.64) and 17.00 (1.41); VB+S: 21.75 (5.37) and 62.25 (0.95); VB LV+S: 24.50 (3.87) and 72.75 (1.89); VB HV+S: 28.75 (8.46) and 93.00 (53.63); VB+E: 31.75 (8.38) and 42.75 (4.34); VB LV+E: 47.75 (2.50) and 45.75 (3.20); VB HV+E: 49.25 (25.50) and 45.75 (2.75). Significant differences (p cements and polymerization condition as well as for the interaction between them. Instructions regarding polymerization of the adhesive layer must be followed when adhesive systems are used in combination with dual polymerized resin based cements. Otherwise, final film thickness of the adhesive and the resin cement could be affected.

  9. Influence of Bovine Dentin Site on the Bond Strength of Resin Cement

    OpenAIRE

    Tohru, HAYAKAWA; Hiroyuki, Mishima; Shuichi, YAMAKAWA; Mikiko, MASUDA; Masahiro, AIDA; Kimiya, NEMOTO; Yukishige, Kozawa; Department of Crown and Bridge Prosthodontics, Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo; Department of Dental Materials, Research Institute of Oral Science, Nihon Univerity School of Dentistry at Matsudo; Department of Anatomy, Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo

    2001-01-01

    The purpose of this study is to investigate the influences of types of resin cements and dentin site(crown and root part)on the adhesion of resin cement to dentin. Three types of resin cements; Super-Bond C&B, Bistite II and Scotchbond Resin Cement were used. The tensile bond strength of each resin cement to crown and root dentin of bovine incisors was measured after 24 hours immersion in water at 37℃. Super-Bond C&B showed no significant difference in bond strength between crown and root den...

  10. Evaluation of a new, macroporous polyvinylpyridine resin for processing plutonium using nitrate anion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F.

    1989-04-01

    Anion exchange in nitric acid is the major aqueous process used to recover and purify plutonium from impure scrap materials. Most strong-base anion exchange resins incorporate a styrene-divinylbenzene copolymer. A newly available, macroporous anion exchange resin based on a copolymer of 1-methyl-4-vinylpyridine and divinylbenzene has been evaluated. Comparative data for Pu(IV) sorption kinetics and capacity are presented for this new resin and two other commonly used anion exchange resins. The new resin offers high capacity and rapid sorption kinetics for Pu(IV) from nitric acid, as well as greatly stability to chemical and radiolytic degradation. 8 refs., 14 figs.

  11. Biocompatibility and cytotoxicity of two novel low-shrinkage dental resin matrices.

    Science.gov (United States)

    Jan, Yih-Dean; Lee, Bor-Shiunn; Lin, Chun-Pin; Tseng, Wan-Yu

    2014-06-01

    To reduce the polymerization shrinkage of dental composite resin, we used two different ratios of toluene 2,4-diisocyanate (TDI) or 1,6-hexamethylene diisocyanate (HDI) as functional side chains of bisphenol A-glycidyl methacrylate (bis-GMA) to synthesize two series of new dental resin matrices. This study evaluated the biocompatibility and cytotoxicity of these two series of new resin matrices. Two series of new dental resin matrices with the ratios of TDI or HDI functional side chain to bis-GMA (defined as B group) being 1:4, 1:2, 1:1 and 3:2 (defined as T1/4, T1/2, T1, T3/2, and H1/4, H1/2, H1, H3/2 groups, respectively) were synthesized. Each resin sample was light cured and immersed in the culture medium for 24 hours to make the extract solution. Then, human gingival fibroblasts were cultured in different extract solutions for 72 hours. The cytotoxicities of different resins were evaluated by microtitertetrazolium (MTT) assay, the levels of cell-produced reactive oxygen species (ROS) induced by different extract solutions was measured. Resins of the T1/4 and B groups revealed significantly higher cytotoxicity than resins of other groups. However, resins of the T1 and T3/2 groups exhibited less cytotoxicity. In general, resins of the TDI-modified groups showed equal or less cytotoxicity and induced equal or lower levels of ROS than the corresponding resins of the HDI-modified and B groups. Our results showed that the TDI-modified resin matrices containing more functional side chains were less cytotoxic than the corresponding HDI-modified resin matrices. When the ratio of functional side chain to bis-GMA is increased, the stereo hindrance of resin structure is increased, more toxic resin monomers are trapped in the complicated resin structure, and thus the resin matrix reveals less cytotoxicity. The TDI-modified resin matrices exhibit higher stereo hindrance of resin structure and thus show less cytotoxicity than the corresponding HDI-modified resin matrices

  12. Deep drawability of Ti/resin/Ti laminated sheet

    Science.gov (United States)

    Hardada, Yasunroi; Hattori, Shuji

    2017-10-01

    Aiming to enhance functionality of titanium cup, the formability of titanium/resin/titanium laminated sheet by deep drawing was investigated. Although pure titanium has excellent corrosion resistance, the density of titanium is higher than that of light metals, such as aluminum and magnesium. Part of the titanium cup made of resin allows for weight reduction of the cup. Furthermore, the clad cup is more likely to have heat retention and protection against vibration characteristics. In the experiment, the materials were pure titanium and polycarbonate. The initial thickness of the sheet was 0.2 to 0.5 mm in thickness. A total plate thickness of the blank was 1.0 to 1.5 mm in thickness. The blank diameter is 70 mm. The laminated sheet was constituted by interposing resin between two titanium sheets. Each sheet in stacked condition was not joined each other. In the deep drawing process, the laminated sheet was employed and a flat sheet blank was formed into a circle by a punch. For the prevention of seizure in contact area between a drawing tool and titanium, titanium blank was treated by oxide coating. By this method, the fresh and clean titanium is not in direct contact with the die during the forming due to the existence of the oxide layer. The deep drawing was carried out to investigate the formability. The laminated sheet was successfully drawn without the cracks. The section of the drawn cup was observed to examine a formability of the resin sheet. The reduction rate of the thickness was less than 10%. It was found that the titanium/resin/titanium clad cup was successfully drawn.

  13. Effect of Distance on Light Transmission Through Polymerized Resin Composite.

    Science.gov (United States)

    Aromaa, M K; Lassila, L V J; Vallittu, P K

    2017-09-01

    Light transmittance of dental composites varies between products and shades, but also light curing units differ to each other in their irradiance and fiber optic structure of curing tip. The aim of this study was to investigate whether there is linear relationship between the distance of the curing tip to the resin composite and irradiance at lower surface of the resin composite. Disks of 1 mm thickness (6mm diameter) were fabricated. Light transmittance (intensity) through the disk was measured at distance of 0, 2, 4, 6, 8, 10 mm from the light tip with two light curing units Elipar S10 (3M-ESPE) and Silverlight (GC). Irradiance ratio (irradiance on the sensor surface without the composite disk / with the composite disk) was calculated and plotted against the distance of the light curing tip. Statistical analysis was carried out using analysis of covariance (ANCOVA, Tukey's, α =0.05). Irradiance ratio varied between 18% to 24% with Silverlight and 21% to 26% with Elipar S10 light curing units. There were statistically significant differences between the ratios with different distances of the light curing tip (p⟨0.05). Interestingly, the highest irradiance ratio for Elipar S10 unit was found with 4 mm distance of the tip, whereas Silverlight unit had the highest ratio with 6 mm distance. Out of two tested resin composites, the flowable composite showed higher irradiance ratio than regular packable resin composite. Increase of distance of the light curing tip from the composite surface decreased the absolute irradiance underneath of composite, as expected. However, there seemed to be device dependent optimal distance of 4-6 mm to reach the most efficient irradiance ratio through the composite resin keeping in mind that most efficient transmission of light through the material is reached by having light curing tip in contact to the material. Copyright© 2017 Dennis Barber Ltd.

  14. Profile of Fluoride Release from a Nanohybrid Composite Resin

    Directory of Open Access Journals (Sweden)

    Raquel Assed Bezerra Silva

    2015-02-01

    Full Text Available The aim of this study was to evaluate in vitro the amount and profile of fluoride release from a fluoride-containing nanohybrid composite resin (Tetric® N-Ceram by direct potentiometry. Thirty specimens (5 mm diameter x 3 mm high; n=10/material were made of Tetric® N-Ceram, Vitremer® resin-modified glass ionomer cement (RMGIC (positive control or Filtek® Z350 nanofill composite resin (negative control. The specimens were stored individually in plastic tubes containing 1 mL of artificial saliva at 37°C, which was daily renewed during 15 days. At each renewal of saliva, the amount of fluoride ions released in the solution was measured using a fluoride ion-selective electrode with ion analyzer, and the values obtained in mV were converted to ppm (µg/mL. Data were analyzed statistically by ANOVA and Tukey’s post-hoc test at a significance level of 5%. The results showed that the resins Tetric® N-Ceram and Filtek® Z350 did not release significant amounts of fluoride during the whole period of evaluation (p>0.05. Only Vitremer® released significant amounts of fluoride ions during the 15 days of the experiment, with greater release in first 2 days (p0.05. In conclusion, the nanohybrid composite resin Tetric® N-Ceram did not present in vitro fluoride-releasing capacity throughout the 15 days of study.

  15. Fissure sealant materials: Wear resistance of flowable composite resins.

    Science.gov (United States)

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm(2) and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm(2)of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  16. Evaporation of low-volatility components in polymeric dental resins.

    Science.gov (United States)

    Forman, Darren L; McLeod, Robert R; Shah, Parag K; Stansbury, Jeffery W

    2015-09-01

    This study provides measurement of the volatility of selected photoinitiators and monomers used in dental adhesive resins. A detailed determination of the spatial and temporal character of camphorquinone (CQ) volatilization with respect to air flow conditions as well as media viscosity is assessed to gauge the effect of evaporative loss on the photopolymerization process and the photopolymers formed. Vapor pressures of materials are measured by thermogravimetric analysis. A quantitative model assuming one-dimensional Fickian diffusion with surface evaporation is presented and compared with measured photoinitiator volatilization from viscous and non-viscous resin samples, obtained by spectrophotometry and confocal microscopy. Model resins are prepared and subject to airthinning followed by photocuring, monitored in real-time by Fourier transform infrared spectrometry. Vapor pressure measurements of the individual components of the adhesive resin span nearly four orders of magnitude, with the photoinitiator CQ near the middle (0.6Pa) and the monomer HEMA at the upper end (10Pa). We see depth-averaged CQ loss from non-viscous open films, while depthresolved measurements of viscous droplets show strong surface-localized CQ depletion. Good agreement is observed between measurements and the model. Finally, air-thinning of samples prepared with more-volatile photoinitiator and monomer is shown to cause longer induction times, slower early-stage polymerization rates and lower late-stage degree of conversion. Widely used compounds with vapor pressures as low as 0.6Pa (0.001Torr) undergo significant volatilization from samples ventilated under conditions generally representative to clinically used air-thinning procedures, with the potential to adversely affect the photopolymerization of both viscous and non-viscous resins. The inverse relationship between air-thinning and adhesive bond strength, observed elsewhere, may be partially caused by this same effect. Copyright

  17. Fissure sealant materials: Wear resistance of flowable composite resins

    Directory of Open Access Journals (Sweden)

    Sohrab Asefi

    2016-08-01

    Full Text Available Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow, Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists. A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm2 and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm2of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  18. [Styrene migration into wine contained in polyester resin tanks].

    Science.gov (United States)

    Giffone, M; Brun, S

    1978-01-01

    The use of polyester resins in wine tanks manufacture or coating has widely spread during the past five years; this type of material has been and is still the source of organoleptic damage due to non polymerized sytrene migration into urine. Sytrene is a solvant often used in resin polymerization: it act as a reticulation agent of insaturated linear polyester. Polymerization at room temperature is allowed gy additives but has to be completed in warm air or in steam. An excess of styrene is often used for a polymerisation as complete as possible and remains on a free form. Then it migrates from the tank walls into the wine. For a better understanding of the styrene migration mechanism studies were performed on two levels: from small containers (4 l) kept in the laboratory and from tanks (30 hl) set up in an I.N.R.A. wine estate in all conditions usually realized in practice. Influence of time, temperature and alcohol content were studied. Styrene migration was interpreted as a diffusion phenomenom and styrene diffusion coefficients were calculated for several temperatures. Knowledge of these coefficients and of styrene content of the tank walls allow the prediction of a tank behaviour in time. Other substances that styrene were detected in wine and in tank walls, they are impurities either from resins like ethylbenzene, or from the catalyst like mesityl oxide. The lattest has never been mentioned in the litterature. From the results obtained it is possible to give some advices to manufacturers and users of polyester resin tanks, about the quality of raw materials, resins and additives along with the conditions carried and for their use and about the control of monomer styrene content in the walls of just manufactured tank.

  19. The influence of monomeric resin and filler characteristics on the performance of experimental resin-based composites (RBCs) derived from a commercial formulation.

    LENUS (Irish Health Repository)

    Hahnel, Sebastian

    2012-04-01

    To explore experimental RBCs derived from a successful commercially available RBC (Grandio) to investigate resin monomer blend and filler parameters (volume fraction, density and diameter) on RBC performance.

  20. [The effect of composition on the mechanical properties of composite resin].

    Science.gov (United States)

    Yang, H S; Park, Y J

    1989-02-01

    The objective of this investigation was to determine whether the composition of composite resin affects the amount of residual monomers and the strength of resin. Six types of resin composition were designed and 30 composite resin specimens were made in glass mold of 6mm diameter and 3mm height. The residual monomer of each specimen was extracted by 10cc ethanol solution for 1, 2, and 3 days of experiment. UV/Vis spectrophotometer was used to estimate the amount of residual monomer of the specimen, and universal testing machine was used to test the diametral tensile strength of the composite resin. The results were as follow; 1. Composite resins of 1% benzoyl peroxide concentration released the higher level of residual monomers than the resin of 0.8% benzoyl peroxide concentration. 2. t-Butylaminoethylmethacrylate.HF of 17% concentration exhibited the greater level of residual monomer than the other resin monomers. 3. As the concentration of the trimethylolpropane trimethacrylate increased, the amount of Bis-GMA residual monomer increased. 4. Composite resin of 1% benzoyl peroxide concentration showed higher tensile strength than the resin of 0.8% benzoyl peroxide concentration. 5. As the concentration of trimethylolpropane trimethacrylate increased above 50%, the strength of the composite resin decreased.