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Epoxy injection repairs to concrete in 225-B Building

Description: In 1982, the damaged anchor areas (67 total) in the Operating Gallery and cold manipulator shop ceiling reinforced concrete slabs were epoxy injection repaired by Construction Technology Laboratories (CTL), Portland Cement Association. The through depth vertical cracks (10 total) in the ceiling slabs in the galleries and manipulator shops were sealed and structurally repaired using epoxy injection procedures. The details of the epoxy reRair are reported. Sonic nondestructive (NDT) testing before and after the epoxy injection repairs were made by CTL to confirm that the repairs are structurally effective. CTL recommended to expedite the installation of lateral bracing for the manipulator monorail in order to avoid re-darnage to the repaired anchor areas.
Date: September 19, 1996
Creator: Vollert, F.R.
Partner: UNT Libraries Government Documents Department

Development and Characterization of a New Epoxy Foam Encapsulant as an Ablefoam Replacement

Description: A new epoxy foam encapsulant, EF-ARIO/20, has been developed at Sandia National Laboratories (SNL) as a replacement for Ablefoam", an epoxy foam encapsulant used in the W76 Arming, Fusing, and Firing (Al%@) system. Since it contained toxic ingredients including a known carcinogen, Ablefoarn" is no longer commercially available. It has been demonstrated by scanning electron microscopy (SEM) that the microstructure of the new epoxy foam is similar to that of Ablefoam@. Mechanical properties of tensile and compressive strength, and tensile and compressive modulus, and thermal properties of glass transition temperature (.TJ, and coefficient of thermal expansion (CTE) have been measured for the new foam. Electrical properties of dielectric constant, dissipation factors, volume resistivity, and dielectric strength were also measured. These property measurements are comparable to those of Ablefoam@. Development and characterization of the new foam will be discusse~ and a comparison of mechanical, thermal, and electrical properties for the new epoxy foam and Ablefoam@ will be reported.
Date: December 1, 1998
Creator: Rand, P.B. & Russick, E.M.
Partner: UNT Libraries Government Documents Department

New Adventures in the Chemistry of Polycarboncyclic Ring Systems

Description: I. Diels-Alder reactions of 1,2,3,4,9,9-hexachloro-1,4,4a,8a-tetrahydro-1,4-metha- nonaphthalene (16) and 1,2,3,4,9,9-hexachloro-1,4,6,7-tetrahydro-1,4-methanonaphthalene (17) toward dienophiles N-methyl-1,2,4-triazoline-3,5-dione (MTAD), N-phenyl-1,2,4-triazoline-3,5-dione (PTAD) and/or N-methylmaleimide (NMM) have been examined. II. Epoxides derived from functionalized 1,4,4a,9a-tetrahydro-9,10-dioxo-1,4-methanoanthracenes (1a and 1b) undergo acid- and base-promoted intramolecular nucleophilic ring-opening to form new polycyclic alcohols. III. The title cycloalkylidenecarbene has been generated via reaction of 8-methylenepentacyclo[5.4.0.0^{2,6}.0^{3,10}. 0^{5.9}]undecan-11-one (44) with diethyl diazomethyl-phosphonate (DAMP). This species could be trapped in situ by cyclohexene, thereby affording the corresponding cycloadduct 46a and 46b.
Date: December 1997
Creator: Dong, Zhiming (Eric)
Partner: UNT Libraries

Quantitative prediction of stresses during thermoset cure

Description: Two thin-walled Al tubes were filled with epoxy which were cured isothermally; one tube was instrumented with strain gauges, and the other with thermocouples. Finite element codes were used. Predicted and measured centerline hoop strains are shown; predictions and measurements agree. This is being applied to encapsulated components.
Date: July 1, 1996
Creator: Adolf, D.; Chambers, B. & Burchett, S.
Partner: UNT Libraries Government Documents Department

Measurement techniques for evaluating encapsulant thermophysical properties during cure

Description: Sandia now has the capability to evaluate stresses during cure of epoxies with finite element codes. Numerous material parameters are needed as input to these codes. I present a relatively quick set of tests which enable evaluation of the required thermophysical properties. Ease and accuracy of the tests improve as the reaction rate of the thermoset slows. Material parameters for common encapsulants at Sandia are presented in tables.
Date: June 1, 1996
Creator: Adolf, D.
Partner: UNT Libraries Government Documents Department

Rigid Square Inclusion Embedded within an Epoxy Disk: Asympototic Stress Analysis

Description: The asymptotically singular stress state found at the tip of a rigid, square inclusion embedded within a thin, linear elastic disk has been determined for both uniform cooling and an externally applied pressure. Since these loadings we symmetric, the singular stress field is characterized by a single stress intensity factor, and the applicable calibration relationship has been determined for both fully bonded and unbended inclusions. A lack of interfacial bonding has a profound effect on inclusion-tip stress fields. A large radial compressive stress is generated in front of the inclusion tip when the inclusion is well bonded, whereas a large tensile hoop stress is generated when the inclusion is unbended, and frictionless sliding is allowed. Consequently, an epoxy disk containing an unbended inclusion appears more likely to crack when cooled than a disk containing a fully bonded inclusion. Elastic-plastic calculations show that when the inclusion is unbended, encapsulant yielding has a significant effect on the inclusion-tip stress state. Yielding relieves stress parallel to the interface and greatly reduces the radial compressive stress in front of the inclusion. As a result, the encapsulant is subjected to a nearly uniaxial tensile stress at the inclusion tip. For a typical high-strength epoxy, the calculated yield zone is embedded within the region dominated by the elastic hoop stress singularity. A limited number of tests have been carried out to determine if encapsulant cracking can be induced by cooling a specimen fabricated by molding a square, steel insert within a thin, epoxy disk. Test results are in qualitative agreement with analysis. Cracks developed only in disks with mold-released inserts, and the tendency for cracking increased with inclusion size.
Date: February 2, 1999
Creator: Guess, T.R. & Reedy, E.D.
Partner: UNT Libraries Government Documents Department

Interphase mechanical properties in epoxy-glass fiber composites as measured by interfacial force microscopy

Description: The research focuses on the measurement of the nanomechanical properties associated with the interphase region of a polymer matrix fiber composite with a nanometer resolution in chemically characterized model composites. The Interfacial Force Microscope (IFM) is employed to measure, with nanometer resolution, the mechanical properties of the interphase region of epoxy/glass fiber composites. The chemistry of the interphase is altered by the adsorption on to the fiber surface a coupling agent, 3-aminopropyltrimethoxy silane ({gamma}-APS) which is known to covalently bond to the glass fiber surface and the epoxy resin. Recent work utilizing FT-IR fiber optic evanescent wave spectroscopy provides a method for the characterization of the interphase chemistry. This technique has been used to investigate the interphase chemistry of epoxy/amine curing agent/amine-terminated organosilane coupling agent/silica optical fiber model composites. This body of work has shown that a substantial fraction of the amine of the organosilane-coupling agent does not participate in a reaction with the epoxy resin. This evidence suggests an interphase that will have mechanical properties significantly different than the bulk epoxy/amine matrix. Previous research has shown that drastic changes occur in the coupling agent chemistry, interphase chemistry, and composite mechanical properties as the amount of adsorbed coupling agent is varied over the industrially relevant range used in this work. A commercially available epoxy resin, EPON 828, and aliphatic amine-curing agent, EPI-CURE 3283, make up the polymer matrix in this study. The reinforcement is silica optical or E-glass fibers.
Date: April 1, 1998
Creator: Winter, R.M. & Houston, J.E.
Partner: UNT Libraries Government Documents Department

THE COVALENT BINDING OF ENANTIOMERIC BENZO [A] PYRENE DIOL EPOXIDES TO DOUBLE STRANDED DNA IS STEREOSELECTIVE

Description: Reaction of optically pure (+) and (-) 7{beta},8{alpha}-dihydroxy-9{alpha},10{alpha}-epoxy-7,8,9.10-tetrahydrobenzo[a]pyrene with DNA in vitro yielded diastereomeric covalent adducts with the exocyclic amino groups of deoxyguanosine and deoxyadenosine. The ratio of two deoxyguanosine diastereomers derived by reacting the (+) and (-) hydrocarbons with native calf thymus and double stranded 0X174 DNA was 20:1 while reaction of the enantiomers with heat denatured calf thymus and single stranded 0X174 DNA resulted in a ratio near 1:1. In contrast, deoxyaadenosine diastereomer pairs were approximately 1:1 in all cases studied. The (+) and (-) enantiomers of the benzo[a]pyrene diol epoxide, therefore, interact asymmetrically with the guanine binding sites of double stranded but not single stranded polydeoxynucleotides. In contrast, reaction of the enantiomers with adenine is not stereoselective.
Date: July 1, 1978
Creator: Meehan, T. & Straub, K.
Partner: UNT Libraries Government Documents Department

Benzo[a]Pyrene Diol Epoxide Perturbation of Cell Cycle Kinetics of Synchronized Mouse Liver Epithelial Cells

Description: A cell cycle synchronization system is described for the analysis of the perturbation of cell cycle kinetics and the cycle-phase specificity of chemicals and other agents. We used the system to study the effects of ({+-})r-7, t-8-dihydroxy-t-9, 10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BaP diol epoxide) upon the cell cycle of mouse liver epithelial cells(NMuLi). BaP diol epoxide(0.6 uM) was added to replated cultures of NMuLi cells that had been synchronized in various stages of the cell cycle by centrifugal elutriation. DNA histograms were obtained by flow cytometry as a function of time after replating. The data were analyzed by a computer modeling routine and reduced to a few graphs illustrating the 'net effects' of the BaP diol epoxide relative to controls. BaP diol epoxide slowed S-phase traversal in all samples relative to their respective control. Traversal through G{sub 2}M was also slowed by at least 50%. BaP diol epoxide had no apparent effect upon G{sub 1} traversal by cycling cells, but delayed the recruitment of quiescent G{sub 0} cells by about 2 hrs. The methods described constitute a powerful new approach for probing the cell cycle effects of a wide variety of agents. The present system appears to be extremely sensitive and capable of characterizing the action of agents on each phase of the cell cycle. The methods are automatable and would allow for the assay and possible differential characterization of mutagens and carcinogens.
Date: July 1, 1980
Creator: Pearlman, A.L.; Navsky, B.N. & Bartholomew, J.C
Partner: UNT Libraries Government Documents Department

Low density foams for vacuum insulation

Description: An investigation to find an open cell foam polymer for vacuum insulation has shown an epoxy-modified isocyanurate foam to be superior to urea/formaldehyde foams. Though improved during the study, the urea/formaldehyde foams still had problems of being too friable, dimensionally unstable, and possessed of the odor of unreacted formaldehyde. Thermogravimetric and thermomechanical analyses showed the epoxy-modified isocyanurate foam to be more thermally and dimensionally stable than the urea/ formaldehyde foams. (auth)
Date: September 1, 1973
Creator: Richardson, W.E.
Partner: UNT Libraries Government Documents Department

Characterization of interphase structure using neutron reflection

Description: Neutron reflection is one of only a few characterization techniques which can be used to study buried interfaces in situ. While restricted to model samples, interfacial density and composition profiles can be obtained with a resolution of {approx}5 {angstrom} using isotopic substitution (typically H/D for organic materials). We are using neutron reflection to address several problems of fundamental importance to the durability of organic/inorganic interphases. One important focus of this study is water adsorption within interphases with and without coupling agents. From the time and temperature dependence of moisture uptake and removal in vacuum, information regarding the nature of the interaction of water with the interphase species can be obtained.
Date: May 1, 1997
Creator: Kent, M.S.; McNamara, W.F. & Domeier, L.
Partner: UNT Libraries Government Documents Department

Autonomic Healing of Epoxy Using Micro-Encapsulated Dicyclopentadiene

Description: The autonomic healing ability of an epoxy adhesive containing micro-encapsulated dicyclopentadiene (DCPD) was evaluated. The epoxy resin used was Epon 828 cured with either Versamid 140 or diethylenetriamine (DETA). Variables included total weight percent of microcapsules (MCs) and catalyst, as well as the catalyst to DCPD ratio. The degree of healing was determined by the fracture toughness before and after ''healing'' using double-cantilever beam analysis. It was found that the degree of self-healing was most directly related to the contact area (i.e. crack width) during healing. Temperature also played a significant role. Observed differences between the results of this study and those in literature are discussed.
Date: May 1, 2003
Creator: THOMA, STEVEN G.; GIUNTA, RACHEL K.; STAVIG, MARK E.; EMERSON, JOHN A. & MORALES, ALFREDO M.
Partner: UNT Libraries Government Documents Department

A performance evaluation of coating systems for long term aqueous immersion service

Description: The static immersion of coated steel panels in various media representative of chemical and waste processes around the Oak Ridge Y-12 Plant was terminated after 16 months exposure for evaluation of coating performance and comparison with observations collected following 1, 6, and 11 months exposure. In each environment, a wide range of coating performance was observed, including some coatings unsuitable for use in the test environment (despite the high recommendation of the vendor). Further, coating performance as a function of time suggests a test duration of at least several months is required to fully assess candidate coating performance for specific applications. The performance of many coatings, particularly in the most alkaline environment, was adversely affected by the imposition of supplemental cathodic protection on the coated test panels.
Date: November 8, 1994
Creator: Pawel, S.J.
Partner: UNT Libraries Government Documents Department

Interim report on the development of an epoxy resin bonded explosive

Description: This report summarizes the work done to date on the development of an epoxy resin bonded explosive (HMX). The original target values have been satisfied and further investigations will be on a semi-pilot plant scale. The following characteristics have been determined on laboratory specimens. Compressive strength, 11-12,000 psi; sensitivity (50 % height) 31 cm; density, 1.81 gm/cc; vacuum stability (cc gas/gm/24 hrs at 100{degrees}C), .42 cc/gm.
Date: August 19, 1957
Creator: Archibald, P.
Partner: UNT Libraries Government Documents Department

Optical Isolation of Scintillating Tiles Using TiO{subscript 2} Doped Epoxy for the D-Zero ICD in Run II

Description: A Run II D0 Inter Cryostat Detector tile array will be composed of 16 identical modules. Each module contains 12 optically isolated scintillating tile elements, each with dimension of 0.1 x 0.1 in {eta} and {phi} in the pseudora-pidity region from 1.1 to 1.4. The 12 tiles in a module are formed by routing grooves in a single piece of scintillator - optical isolation is achieved by fill-ing the grooves with a white re ective epoxy. The procedure for filling these isolation grooves is described here.
Date: February 16, 1999
Creator: Gallas, Elizabeth
Partner: UNT Libraries Government Documents Department

Mechanical properties, microscopy, and failure mechanisms of carbon fiber reinforced epoxy laminated composites

Description: The mechanical behavior of quasi-isotropic and unidirectional epoxy- matrix carbon-fiber laminated composites subjected to compressive loading at strain rates of 10{sup {minus}3} and 2000 s{sup {minus}1} are described. Failure in the studied composites was dominated by delamination which proceeded by brittle fracture of the epoxy matrix. The matrix-fiber bonding in these composites is very strong and prevented the occurrence of significant fiber-pullout. The mode I delamination strain energy release rate of the unidirectional composites was determined using the double cantilever beam and hole in plate compression methods. The DCB method indicated a significant R curve effect attributed to fiber bridging while the presently available hole in plate analytical methods show questionable validity for highly anisotropic materials.
Date: December 1995
Creator: Thissell, W. R.; Zurek, A. K. & Addessio, F.
Partner: UNT Libraries Government Documents Department

Epoxy and acrylate stereolithography resins: In-situ measurements of cure shrinkage and stress relaxation

Description: Cross-sections of resin strands. Techniques were developed to make in situ measurements of gelled resin to determine linear shrinkage, stress-strain response and stress relaxation of single strands of SL 5170 epoxy and SL 5149 photocurable resins. Epoxy strands shrank approximately 1.4% and the acrylate strands about 1.0% after a single exposure. No forces were measured during cure shrinkage of strands following the first laser exposure. In multiple laser exposures, the acrylate continues to shrink; whereas (University of Dayton data) no additional shrinkage is observed in epoxy strands on a second hit. In force relaxation tests, a strand is drawn and then a 0.5% step strain is applied after different elapsed times. The epoxy initial modulus evolves (increases) with elapsed time following draw of the strand, and this evolution in modulus occurs after linear shrinkage has stopped. On the other hand, acrylates show no evolution of modulus with elapsed time following a single laser draw; i.e., once shrinkage stops after one laser hit, the initial modulus remains stable with elapsed time. Finally, relaxation response times of epoxy strands get larger with increasing elapsed time after laser draw. In acrylate strands there was no evolution in initial modulus with elapsed time after a single draw so relaxation times are not a function of elapsed time after a single hit with the laser.
Date: March 1, 1995
Creator: Guess, T.R.; Chambers, R.S.; Hinnerichs, T.D.; McCarty, G.D. & Shagam, R.N.
Partner: UNT Libraries Government Documents Department

Correlation of the crack initiation stress with epoxy network topology

Description: Much controversy surrounds the dependence of stress intensity factor of glassy thermosets, epoxies in particular, with crosslink density. One could scan the literature and find references that claim K{sub Ic} increases with crosslink density, decreases with crosslink density, or is independent of crosslink density. The authors feel that two factors contribute to this confusion. First, a typical method for assessing this dependence relies on modifying the crosslink density by changing the precursor epoxy molecular weight. On the other hand, one could change stoichiometry or quench the reaction at intermediate extents of reaction to obtain large changes in crosslink density. However, most studies have not measured the resulting stress intensity factor of these partially cured systems at constant T-T{sub g}, where T{sub g} is the glass transition temperature of the epoxy. Since T{sub g} can change significantly with cure and since fracture processes at the crack tip are dissipative, they must work at constant T-T{sub g} to ensure that the nonlinear viscoelastic mechanisms are fairly compared. In this study, they quenched the reaction of the diglycidyl ether of bisphenol A (DGEBA) and diethanolamine (DEA) at various stages past the gel point and measured the three-point-bend stress intensity factor at a constant T-T{sub g} = {minus}50 C. The trend is clear and significant; increasing crosslink density directly increases the load-to-fail.
Date: March 1, 1997
Creator: Adolf, D.; Weeks, T. & McCoy, J.
Partner: UNT Libraries Government Documents Department

Moldable Transient Suppression Polymer Composite

Description: The objective of the CRADA was to cooperate in the development of a moldable transient suppression polymer composite that can be used to protect electrical equipment and electronics from damage caused by electrical disturbances and faults. The composite was to provide a solid- state means of fault current limitation, particularly for high-current applications. The composite was envisioned to have the following properties: (1) be moldable and therefore suited to the automated manufacture at a low cost; (2) operate with greater speed and reliability than electromechanical devices; and (3) operate in conjunction with appropriately designated mechanical breakers to limit the current and energy under short-circuit fault conditions, thereby providing improved protection to equipment connected to the circuit. The technical work of the project was in part shared between Lockheed Martin and the General Electric Company and in part divided between the participants according to their capabilities. Work was performed in the Oak Ridge K-25, Y-12, and X-10 facilities of Lockheed Martin and at the General Electric Company Corporate Research and Development (GE-CR&D) and Electrical Distribution and Control (GE-ED&C) facilities. Materials were fabricated in facilities of the Y-12 Development. Department, where polymers were filled with varying amounts of conductive materials. However, as the effort was reduced because of curtailed DOE funding, GE took over fabrication of filled epoxies and then assumed responsibility for all materials fabrication. Electrical testing and theoretical modeling by Lockheed-Martin were performed at X-10, excepting that some pulse testing of materials and the development of specialized pulse test apparatus was done at the K-25 site. GE shared in low-power electrical testing at CR&D and pefiormed high-power electrical testing using specialized facilities at the ED&C. GE took responsibility for setting the performance requirements of the materials for their product applications. Other phases of the project such as product integration, breaker ...
Date: November 24, 1998
Creator: Campbell, v.b. & modine, f.a.
Partner: UNT Libraries Government Documents Department

Fabrication and evaluation of uniform and gradient density epoxies

Description: Filled epoxy materials which vary in density in a designed manner have been fabricated and their mechanical properties evaluated. Density variations were produced by incorporating different volume fractions of either glass microballoons (GMB) or alumina. Several different sample types were evaluated including uniform density (0.8 g/cm{sup 3} < {rho} < 2.0 g/cm{sup 3}) samples and gradient density samples (GMB only, 0.8 g/cm{sup 3} < {rho} < 1.2 g/cm{sup 3}). The uniform density specimens were evaluated for the effects of filler type and concentration on modulus and toughness. Results indicated that addition of alumina filler significantly increased the resulting modulus while addition of GMB had little measurable effect. These differences could be understood in terms of the differing moduli of the additives relative to that of the epoxy matrix. In the former case the alumina particulates had a modulus much greater than that of the epoxy while in the latter case, the modulus of the GMB additive was only slightly greater than that of the matrix. Addition of either filler significantly degraded the toughness of the composite specimens and precluded the use of gradients to enhance toughness performance. Discontinuous {open_quotes}block{close_quotes} gradients used for testing were fabricated by simple sequential pours of formulations with different GMB loadings and were evaluated for modulus, strength and ductility. Continuous gradients were fabricated in process studies by programmed shifts in the peristaltic pumping/mixing ratio of epoxies filled with either alumina or GMB. None of the continuous gradient materials were mechanically tested. These results suggest that applications utilizing gradient materials containing alumina and similar high modulus fillers to provide designed stiffness rather than improved toughness are the most appropriate targets for future investigation.
Date: November 1, 1997
Creator: Domeier, L.A.; Skala, D.M. & Goods, S.H.
Partner: UNT Libraries Government Documents Department