Showing papers on "Epoxy published in 1970"

Curable polyepoxide compositions

Abstract: This application relates to curable compositions, based on cycloaliphatic epoxides in admixture with epoxy hardeners and polymers of butadiene, which can be cast into articles of desired configuration or used as binders in the preparation of laminates, and cured at elevated temperatures to form articles characterized by excellent physical properties such as tensile strength, toughness, resistivity to development and propagation of internal cracks, heat distortion temperatures and also characterized by excellent electrical properties.

The effect of fibre length and interfacial bond in glass fibre-epoxy resin composites

Abstract: The effect of fibre length on the strength of glass fibre-epoxy resin composites has been examined by beam bending experiments on uniaxially aligned material. The results agree well with theoretical predictions and the critical fibre length is found to be 12.7 mm (0.5 in.). A method of measuring the interfacial shear strength of the fibre-matrix interface has been developed and the measured value of the interfacial shear strength found to be 9.5 N mm−2. The mechanism of shear failure is examined and discussed in detail.

Combined pyrolysis and radiochemical gas chromatography for studying the thermal degradation of epoxy resins and polyimides. I. The degradation of epoxy resins in nitrogen between 400°C and 700°C

Abstract: The thermal degradation of a bisphenol A-based epoxy resin (EP 274) cured with 4,4′-diaminodiphenyl methane (DDM) and with phthalic anhydride (PA) was studied using a radiochemical pyrolysis gas chromatography technique Conclusive evidence for some of the degradation mechanisms of these resins was obtained by pyrolyzing samples containing various 14C-labelled groups and analyzing the products using this method

Coating compositions containing epoxy resins and carboxyl terminated polyesters

Abstract: IMPROVED COATING COMPOSITIONS COMPRISING A BLEND OF AN EPOXY RESIN AND A POLYESTER HAVING A TERMINAL CARBOXYL FUNCTIONALITY BETWEEN BOUT TWO AND FOUR. THE PREFERRED POLYESTER IS THE ESTERIFICATION PRODUCT OF (1) A HYDROXYL TERMINATED POLYESTER AND (2) A CARBOXYLIC ACID-CONTAINING MONOANHYDRIDE COMPOSITION MADE UP OF A MIXTURE OF TRIMELITIC ANHYDRIDE AND DODECNYLSUCCINIC ANHYDRIDE. CARTERING OF COATINGS HAS BEEN VERY SUBSTANTIALLY REDUCED BY USED OF TERMINALLY LOCATED DODECENYLSUCCINIC ANHYDRIDE-PRODUCED SIDE CHAINS ON THE POLYESTER. CRATERING IS STILL FURTHER REDUCED AND SOLUBILITY PARAMETERS ARE IMPROVED BY EMPOLYING A GLYCIDYL ESTER OF A TERTIARY CARBOXYLIC ACID, SUCH AS CARDURA E, IN THE PREPARATION OF THE HYDROXYL TERMINATED POLYESTER.

Epoxy resin and graded acrylic rubber-urethane-acrylate paint and painting process

Abstract: A radiation-curable paint binder dispersion comprises vinyl monomers, an alpha-beta olefinically unsaturated epoxy resin having molecular weight in excess of about 370, and an addition product of a hydroxy-functional acrylic rubber particle, a diisocyanate and a hydroxyalkyl acrylate. The dispersion is applied to substrates and cured thereon by exposure to ionizing radiation, e.g., an electron beam.

Electron probe analysis of freeze-substituted, epoxy resin embedded tissue for ion transport studies in plants.

Abstract: A new technique is described to prepare plant material for electron probe analysis. Root segments 1 mm in length were frozen at-170°, freeze-substituted with anhydrous ether at-30° and infiltrated with Spurr's low-viscosity epoxy resin embedding medium at low temperatures. Sections 1 and 2μ thick were cut anhydrously using hexylene glycol in the ultramicrotome trough, mounted on the polished surface of a Be disc and vacuum coated with 150–200 A aluminum.

Sizing composition and glass fibers treated therewith

Abstract: A SIZING FOR GLASS FIBERS, COMPRISING WATER SOLUBLE EPOXY RESIN, AN ORGANOSILANE, POLYVINYL ACETATE COPOLYMER AND A LUBRICANT IS PROVIDED, WHEREBY THE SIZED GLASS FIBERS IN THE FORM OF STRANDS, POSSESS EXCELLENT INTEGRITY

The fracture energy of some epoxy resin materials

Abstract: The double cantilever beam technique has been used to measure the fracture energy of a series of cured epoxy resins. A range of materials was produced by varying the proportion of resin to hardener agent (Araldite CT200 and hardener HT901 — phthalic anhydride, CIBA Ltd) and by adding silica flour or aluminium powder as a filler.

Method of producing carbon fibers

Abstract: Nonflammable fibers are produced by subjecting a composite fiber comprising a pitch and a synthetic organic polymer bonded uniformly along the longitudinal direction of the fiber to an oxidation treatment to render it infusible and then to a set treatment in air or gaseous nitrogen at a temperature of 200 DEG to 500 DEG C. for at least 2 hours. The nonflammable fiber is converted to carbon fiber by heating to a temperature higher than 800 DEG C. in gaseous nitrogen. Suitable pitches include petroleum asphalt, coal tar pitch, and pitch obtained by baking polyvinyl chloride. Suitable synthetic organic polymers include polyamides, polyesters, polyolefins, polyvinyl chloride, polyvinylidene chloride, polyurethane, epoxy resins, and phenol resins.

Epoxy silane coupling agents

Abstract: THE BONDING OF SILCEOUS SURFACES, SUCH AS GLASS, TO ORGANIC RESINS, SUCH AS POLYAMIDES, IS IMPROVED BY COATING THE SILICEOUS SURFACE WITH A MIXTURE OF 3-GLYCIDOXYPROPYLTRIMETHOXYSILANE AND METHYLTRIMETHOXYSILANE.

A comparison of some imidazole catalysts as epoxy curing agents

Abstract: Some physical properties of epoxy resins cured with 2-substituted imidazoles, e.g., 2-ethyl-4-methylimidazole (EMI-24), and 1-substituted imidazoles, e.g., 1-methylimidazole (MI-1), were studied in order to determine the effect of additional crosslinking that has been proposed to occur with EMI-24. While these catalysts were found to yield identical physical properties in that system, they were found to behave differently when the epoxy resin was flexibilized with a polysulfide rubber. Evidence from infrared (IR) and nuclear magnetic resonance (NMR) spectra proved that imidazoles unsubstituted in the 2-position were being deactivated through their conversion to a dihydroimidazole compound in a proportion related to the amount of polysulfide rubber present. Hence, only imidazoles substituted in the 2-position will cure epoxy–polysulfide rubber systems.

The time dependence of surface energy in cohesive fracture

Abstract: The time-temperature dependence of the cohesive fracture energy is deduced from experiments on a centrally cracked sheet of butadiene-acrylonitrile-acrylic acid viscoelastic terpolymer crosslinked with an epoxy curing agent. Analytic results based upon a cylindrical flaw model of the crack permit the segregation of the fracture energy time dependence from that of the relaxation modulus.

Epoxy resin composition containing a prepolymer of an n n'-bis-imide and a diamine

Abstract: CURED EPOXY RESINS OF GOOD HEAT RESISTANCE ARE MADE BY HEATING AN EPOXY RESIN WITH A PREPOLYMER MELTING BELOW 200*C. MADE FROM AN N,N''-BIS-IMIDE, E.G. N,N''4,4''-DIPHENYLMETHANE-BIS-MALEIMIDE, AND A DIAMINE.

Polyester hot‐melt adhesives. I. Factors affecting adhesion to epoxy resin coatings

Abstract: The peel strength and tensile shear strength of polyester hot-melt adhesives on metals coated with epoxy resins are affected by four characteristics of the polyester: (1) inherent viscosity, (2) glass transition temperature (Tg), (3) degree of crystallinity, and (4) melting point. The inherent viscosity affects the strength, toughness, and crystallinity of the adhesive. The Tg and degree of crystallinity affect the low-temperature adhesive properties; the peel strength is relatively low when the Tg is appreciably above the use temperature. The Tg, degree of crystallinity, and melting point affect the high-temperature adhesive properties. A hot-melt adhesive with high peel and tensile shear strengths from 0° to 120°C is the polyester of 1,4-butanediol and trans-1,4-cyclohexanedicarboxylic acid.

Leaf wax fine structure and ontogeny in Eucalyptus demonstrated by means of a specialized fixation technique

Abstract: SUMMARY The epidermal cells of Eucalyptus leaves are not well preserved by the conventional sectioning methods used for electron microscopy. More satisfactory preservation results from the use of an in vivo perfusion technique using glutaraldehyde or glutaraldehyde-formaldehyde mixtures. This technique preserves wax on the cuticle surface, rendering it insoluble in the organic solvents used for dehydration and embedding in epoxy resins. Using this method, no direct connection is apparent between leaf wax, cuticle, cell wall and cytoplasm. The Golgi bodies appear to produce vesicles which migrate only in the direction of the outer cell wall, and which might liberate wax precursors into the wall, from where they could diffuse through cuticular lamell to polymerize or oxidize at the leaf surface as waxes of characteristic morphology.

Glass fiber articles with a protective layer of polyurethane and method of preparation

Abstract: A coating to protect exposed glass fabric articles comprising polyurethane. The polyurethane is bonded to the glass fabric by applying a graduated premixture of polyurethane and epoxy resin between the polyurethane and glass fabric.

Casting procedure for high quality epoxy layers

Abstract: A PRECISION EPOXY RESIN STRUCTURE IS PREPARED BY CASTING AN EPOXY RESIN ON A MOLD OF OXIDIZED COPPER OR SILVER. THE METHOD IS PARTICULARLY ADAPTED FOR MAKING FLAT EPOXY SUBSTRATES FOR CLOSED FLUX STORAGE ELEMENTS.

Wetting Kinetics and the Strength of Adhesive Joints

Abstract: The work of adhesion, depending solely on the contact angle and surface tension, is unreliable as a guide to the strength of a joint. The kinetics of joint formation, exemplified by the rate of wetting, is also important and can be measured by rate of change of contact angle, a process for which an empirical equation has previously been suggested. A proposed mechanism introduces a viscosity term into the differential form of this equation. A series of metal lacquers was prepared from epoxy, U/F and M/F resins in various ratios and also epoxy/P/F and epoxy/acrylic mixtures. Stainless steel substrates, coated with these lacquers were then cemented together using polyethylene as an adhesive. It is shown that joint strength correlates better with a high wetting constant (γ/ηL) than with a low contact angle except where this is very low.

Accelerator combination for epoxy curing

Abstract: An accelerator combination of N-(3-aminopropyl)piperazine and salicylic acid is synergistic for accelerating the cure of a polyglycidyl ether of a polyhydric phenol cured with a polyoxyalkylenepolyamine. The epoxy resin product is useful in castings, coatings, adhesives, laminates, filament reinforced compositions, seamless flooring, terrazo flooring, crushed-stone aggregates and in grouting, caulking and sealing compositions.

Composite belleville type springs and manufacture

Abstract: Disc spring fabrication of composites, such as fiber glass in epoxy with fiber orientation, composite material, and mounting technique teachings to produce disc springs of uniform high strength, high durability, long fatigue life in high frequency cycling applications, and desirable physical characteristics, such as low weight, electrical insulation, lack of corrosion, graduated loss of load-carrying capacity, and the like.

Limits of linear viscoelasticity and yield of a filled and unfilled epoxy resin

Abstract: An experimental program was performed to determine the limit of linear viscoelastic response, the onset of yielding, and the condition of gross yielding for a pure and quartz particle filled epoxy resin. The onset of yielding was investigated by a number of different tests, e.g., examination of hysteresis loops, photoelasticity. The tests were performed in both tension and compression over a range of loading times. The limit stresses were found to depend strongly on the loading times.

Production of low molecular weight polyanhydrides and epoxy compositions derived therefrom

Abstract: POLYANHYDRIDES ARE PRODUCED BY A NOVEL BULK POLYMERIZATION PROCEDURE FROM MALEIC MONOMERS AND ALKYL STYRENES. THE POLYANHYDRIDES, OF LOW MOLECULAR WEIGHT AND CONTAINING MALEIC MONOMER TO ALKYL STYRENE IN A RATIO GREATER THAN 1 TO 1, ARE PARTICULARLY USEFUL AS HARDENERS FOR EPOXY RESIN-CONTAINING COMPOSITIONS AND GIVE RISE TO EPOXY COMPOSITIONS WHICH RESULT IN CURED PRODUCTS EXHIBITING HIGH HEAT DISTORTION TEMPERATURES AND EXCELLENT ELECTRICAL AND SHELF LIFE PROPRETIES.

Superposition of dynamic mechanical properties in the glassy state

Abstract: Glassy state beta transition temperatures in cured epoxy resins, showing diglycidyl ether of bisphenol A /DGEBA/ dependence