Materials Sciences: Elastomers and Rubber

Structure-Property Relationships in Thermoplastic Elastomers. III. Segmented Polyacetal-Polyurethanes

04 APR 85

Authors: J. C. W. Chien; MASSACHUSETTS UNIV AMHERST MATERIALS RESEARCH LAB

The full text of this report is not available and therefore is not for sale. This information is provided for reference purposes only.

Dihydroxy terminated polyacetals had been synthesized from aldehydes and glycols and used as soft segments to obtain segmented polyurethane block copolymers. The glass transition temperature (T sub G) of PacPU with 1,350 M sub n polyacetals is raised to -38 C and none was observed for shorter polyacetal chains. The copolymers can be synthesized to have a broad range of mechanical properties such as modulus from 0.5 to 130 MPa, ...

Characteristics of Rapid Cure Magnetic Rubber Inspection Formulations

APR 85

Authors: B. C. Bishop; AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA)

Magnetic rubber inspection (MRI) is a form of magnetic particle inspection. In this particular form the magnetic particles are suspended in a liquid rubber curing at room temperature. The rubber, after the addition of a catalyst and a stablisizer, is poured into, or around, the area to be inspected, where it may be contained, if necessary, by a specially constructed reservoir. A magnetic field, complying with the principles of magnetic ...

Plastic Deformation of Crystalline Polymers

MAR 85

Authors: A. N. Gent; J. Jeong; AKRON UNIV OH INST OF POLYMER SCIENCE

Draw ratios have been measured for samples of polyethylene and trans- polyisoprene, crystallized at various temperatures and at various degrees of orientation. The values obtained range from unity, i.e., no drawing is observed, up to values of about 15X for materials crystallized in the oriented state and then drawn in a perpendicular direction. The results are in rough accord with a simple molecular network model in which network strands are ...

The Role of Molecular Diffusion in the Adhesion of EDPM (Ethhylene- Propylelediene Terpolymer) and EPR (Ethylene-Propylene Copolymer) Elastomers

MAR 85

Authors: M. D. Ellul; A. N. Gent; AKRON UNIV OH INST OF POLYMER SCIENCE

Adhesion of lightly crosslinked sheets of EPDM (ethylene- propylelediene terpolymer) to themselves and to a Mylar substrate has been investigated over wide ranges of peel rate and test temperature. The effect of incorporating ethylene-propylene copolymer (EPR) before crosslinking, to yield a loose macromolecular network containing dissolved linear EPR macromolecules, was also studied. The self-adhesion of these materials was found to be much greater than their adhesion to Mylar, over a ...

Handbook of Plastic Foams

FEB 85

Authors: A. H. Landrock; PLASTICS TECHNICAL EVALUATION CENTER DOVER NJ

This report describes the state of the art of all types of cellular materials particularly those of a polymeric nature (plastics and elastomers). The report is organized in the form of a handbook and has an Introduction and sections on Types of Foams (Cellular Materials), Methods of Manufacture, Foam Properties, Solvent Cementing, and Adhesive Bonding of Foams, Methods of Making Foams Conductive, and Applications. There are two Appendices, one on ...

Electrical Properties of Tank Pad Rubber: A Feasibility Study

JAN 85

41 pages

Authors: L. C. Burton; J. Patt; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG

The full text of this report is available for sale.

The purpose of this work is to investigate the feasibility of electrical measurements for improving the life and reliability of tank track pad rubber. Immediate goals are to determine if electrical measurements can be used to distinguish various types of rubbers used in tank track pads, to obtain more fundamental information about the electrical properties of the rubber, and to make recommendations. The most important results were related to the ...

Finger Materials for Air Cushion Vehicles. Volume 2. Base Fabrics for Finger Materials

DEC 84

Authors: M. M. Schoppee; J. Skelton; M. M. Toney; W. Klemens; ALBANY INTERNATIONAL RESEARCH CO DEDHAM MA

Since the short lifetimes of seal/skirt systems on surface effect vehicles (SEV's) severely limit the long-term serviceability on such craft. A systematic study was undertaken to evaluate the effects of fabric structure on the performance of rubber/fabric skirt materials under conditions of high speed, high-curvature flexing. A series of nylon fabrics was designed and manufactured in which the fiber denier, yarn denier, yarn t

Finger Materials for Air Cushion Vehicles. Volume 1. Flexible Coatings for Finger Materials

DEC 84

Authors: P. K. Conn; I. C. Snell; W. Klemens; BELL AEROSPACE TEXTRON BUFFALO NY

Twenty polymer formulations from ten selected gum rubber polymers or polymer blends and fourteen formulations of castable liquid polyurethane polymers were characterized as coatings for the coated fabric that is the type material used to make flexible fingers for air cushion vehicles. The formulations were screened for crack growth and flexural fatigue resistance; the results were compared to results from a naturak rubber/cisabutadiene blend control coating. In addition, selected polymers ...

Toughening Mechanism in Elastomer-Modified Epoxy Resins. Part 2

DEC 84

56 pages

Authors: A. F. Yee; R. A. Pearson; GENERAL ELECTRIC CO SCHENECTADY NY

The role of matrix ductility on the toughenability and toughening mechanism of elastomer-modified DGEBA epoxies was investigated. Matrix ductility was varied by using epoxide resins of varying epoxide monomer molecular weights. These epoxide resins were cured using 4,4' diaminodiphenyl sulfone (DDS) and, in some cases, modified with 10% HYCAR(R) CTBN 1300X8. Fracture toughness values for the neat epoxies were found to be almost independent on the monomer molecular weight of ...

Modification of Propellant Binder Network for Improvement of Mechanical Properties.

DEC 1984

66 pages

Authors: C. S. Youn-Kim; CALIFORNIA STATE UNIV SACRAMENTO DEPT OF CHEMISTRY

The blending of long straight chain hydroxy-terminated prepolymers with branched shorter chain hydroxy-terminated prepolymers yeidls cured rubbers, whether containing solid fillers or not, that have large improvements in strain capability compared to short chain prepolymer rubbers. Also, the stress capability of the cured rubbers is improved compared to the long chain prepolymer rubbers. Polyethylene glycol 8000 (PEG 8000) was successfully blended with glycidyl azide polymer (GAP) and polydinitropropyl acrylate. Large ...

Rubber-Modified Epoxies. II. Morphology, Transitions, and Mechanical Properties

NOV 1984

Authors: L. C. Chan; J. K. Gillham; A. J. Kinloch; S. J. Shaw; PRINCETON UNIV NJ DEPT OF CHEMICAL ENGINEERING

The mechanical properties of two fully cured rubber-modified epoxy systems, each with varying morphologies and maximum glass transition temperatures developed from different cure conditions, have been investigated versus temperature (-90 to 140 C) using the neat system (glass transition temperature = 167 C) as control. The mechanical properties of the amino- terminated rubber-modified system were more sensitive to cure history than those of the prereacted carboxyl-terminated rubber-modified system. The improvement ...

Poly(dimethylsiloxane)-Polyurethane Elastomers: Synthesis and Properties of Segmented Copolymers and Related Zwitterionomers

NOV 1984

Authors: Y. Xuehai; M. R. Nagarjan; T. G. Grasel; P. E. Gibson; S. L. Cooper; WISCONSIN UNIV-MADISON DEPT OF CHEMICAL ENGINEERING

A series of polyurethane block polymers based on hydroxybutyl- terminated poly(dimethylsiloxane) soft segments of molecular weight 2000 were synthesized. The hard segments consisted of 4,4'-methylenediphenylene diisocyanate (MDI) which was chain extended with either 1,4-butanediol (BD) or N-methyldiethanolamine (MDEA). The MDEA-extended materials were ionized using 1, 3-propane sultone. The weight fraction of hard segments was in range 0.13-o.39. The morphology and properties of these polyurethane elastomers were studied by variety of ...

Structure-Property Relationships in Thermoplastic Elastomers. I. Segmented Polyether-Polyurethanes

26 OCT 1984

Authors: E. J. Woo; G. Farber; R. Farris; C. P. Lillya; J. C. W. Chien; MASSACHUSETTS UNIV AMHERST DEPT OF POLYMER SCIENCE AND ENGINEERING

Segmented poly(ether-b-urethanes) have been synthesized with 2000 MW polypropylene oxide coupled with diisocyanates and diol type chain extenders. The diisocyanates used were symmetric rigid 4,4'-diphenylmethane diisocyanate (MDI), linear aliphatic hexamethylene diisocyanate (HDI) and unsymmetric rigid toluene-2,4-diisocyanate (TDI). The chain extenders were symmetric N,N'-bis(2- hydroxyethyl) terephthalamide (BT) and N,N'-bis(2-hydroxyethyl)-hydroquinone (BH) unsymmetric N,N'-bis(2-hydroxyethyl)isophthalamide, and linear aliphatic butanediol. Hard segment contents ranged from 20 to 40 wt %. The thermal behavior of these ...

Rubber-Modified Epoxies. I. Cure, Transitions, and Morphology

OCT 1984

Authors: L. C. Chan; J. K. Gillham; A. J. Kinloch; S. J. Shaw; PRINCETON UNIV NJ DEPT OF CHEMICAL ENGINEERING

A methodology for investigating cure and its relationship to the development of morphology and transitions for rubber-modified thermosetting systems has been developed. An aromatic tetrafunctional diamine-cured digly- cidyl ether of bisphenol A epoxy resin (maximum glass transition temperature 167 C was modified separately with two reactive liquid rubbers; i.e., a prereacted carboxyl-terminated rubber and an amino-terminated rubber. In order to develop fully cured but distinct cure-dependent morphologies, the systems were ...

Characterization of Novel Binders Based on Energetic Thermoplastic Elastomers

30 SEP 1984

Authors: L. H. Sperling; LEHIGH UNIV BETHLEHEM PA COXE LAB

Beginning in the fall of 1981, a research program was undertaken to develop a series of block copolymers based on novel polyethers. This research is part of the Low Vulnerability Ammunition, LOVA, program of the Office of Naval Research. The principal polymers of interest in this program are the crystalline polyBEMO and polyBAMO, and their thermoplastic elastomers. The most important findings of the past year are: PolyBEMO decomposes endothermally at ...

Proceedings of the Workshop on NDE of Polymers Held at Vimeiro, Portugal on 4-5 September 1984

05 SEP 84

Authors: BRISTOL UNIV (ENGLAND) H H WILLS PHYSICS LAB

Partial contents: Microstructure at the molecular level; Dislocations in wave trains, with special reference to the information they carry about microstructure; Microphase separation in densely crosslinked polymers; Probing the mesophase layer in polymeric composites; Molecular orientation; The contribution of neutron scattering to the determination of chain trajectory in semi-crystalline isotactic polystyrene; Molecular extension and orientation in a crystalline polymer; NDE of laminates; Quality control and lifetime prediction of rubber fabric ...

The Role of Molecular Diffusion in the Adhesion of Elastomers

SEP 1984

Authors: M. D. Ellul; A. N. Gent; AKRON UNIV OH INST OF POLYMER SCIENCE

Butyl rubber (polyisobutylene-co-isoprene) mixed with polyisobutylene was crosslinked to yield elastomeric macromolecular networks containing dissolved linear macromolecules. Adhesion of these materials to themselves (self-adhesion) and to an inert substrate was investigated over a wide range of peel rates and test temperatures. Greatly enhanced self-adhesion was found when linear polyisobutylene molecules of high molecular weight were present, but the strength of adhesion to a rigid inert substrate was hardly affected. ...

Mechanochemical Reactions of Elastomers with Metals

SEP 1984

Authors: A. N. Gent; W. R. Rodgers; AKRON UNIV OH INST OF POLYMER SCIENCE

Metal powders have been incorporated into various elastomers and the mixtures subjected to intense shearing in either an air or a nitrogen atmosphere. The molecular weight after shearing was still relatively high, however, greater than 100 kg/mole. The elastomer was then dissolved and centrifuged to remove the metal particles, and the solution was then analyzed to remove the metal particles, and the solution was then analyzed for reaction products. A ...

T-156 Track with Removable Pad

SEP 1984

12 pages

Authors: A. B. Kendall; STANDARD PRODUCTS CO PORT CLINTON OH

The T-156 track being used on the M1 vehicle is made with the roadwheel path rubber and ground pad rubber molded on an integral unit around a binocular style metal insert. The life of this track shoe is severely limited by the rate of wear and chunking to the ground pad side of the track shoe. This contract is an effort to develop modifications to the shoe body and to ...

Rubber Compound Development for Improved Military Tank Track. Phase II

AUG 1984

Authors: M. B. Hoying; GOODYEAR TIRE AND RUBBER CO ST MARYS OH

Using compound 17CD737 which was developed under phase I of this contract, fifty T-142 track pads and one vehicle set of T-156 track shoe assemblies were fabricated and shipped to TACOM for their analysis.

Unidirectional Fibers and Polyurethane Elastomer Matrix Based Composites - Synthesis and Properties

AUG 84

203 pages

Authors: A. Chakar; SCITRAN SANTA BARBARA CA

The purpose of this work is to provide a synthesis and study of elastomers, then to fabricate and characterize elastomer-fiber reinforcement composites used for making flexible and absorbent structures. To obtain castable elastomer matrices whose vitreous transition temperature may vary from -80 deg C to 110 deg C and exhibiting good adhesion with the fiber we turned to the polyurethane family. jg p9

Spray Coating with Butyl Rubber

AUG 1984

Authors: R. B. Martin; EG AND G FLORIDA COCOA

An inexpensive technique of renewing worn or damaged butyl rubber equipment was developed the Kennedy Space Center, Florida. This technique was required to extend the service life of the protective butyl rubber suits worn by workers handling hypergolic (self-igniting) fuels and oxidizers. Previously, there was no economical way to refurbish suits worn thin through extended use and cleaning. To coat an entire suit, a commercially available two-part butyl adhesive is ...

Runway Rubber Removal Specification Development: Field Evaluation Procedures Development

JUL 84

Authors: R. G. McKeen; L. R. Lenke; R. A. Graul; AIR FORCE ENGINEERING AND SERVICES CENTER TYNDALL AFB FL ENGINEERING AND SERVICES LAB

The phenomenon of runway touchdown zone rubber buildup is a potentially hazardous problem. Methods and equipment are available for evaluating the wet friction coefficient; however, these methods are expensive and require highly trained personnel. Therefore, most airport and airbase managers rely exclusively on visual impressions on rubber buildup in lieu of quantitative measurements. Nonetheless, quantitative evaluation techniques are desireable for evaluating rubber buildup. Rubber buildup alters the texture properties of ...

Direct Analysis of Heavily Loaded Carbon Black Filled Styrene-Butadiene Rubber Used in Tank Track Pads by FT-IR

JUN 1984

Authors: J. M. Sloan; J. P. Clements; ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MA

Infrared spectra have been obtained of a heavily loaded (50 per hundred) carbon black filled styrene-butadiene rubber using a Fourier transform infrared spectrometer (FT-IT). Attenuated total reflectance (ATR) spectroscopy sampling employing a germanium (Ge) internal reflectance element was found to yield quality infrared spectra where other techniques have failed. Subtle changes were observed between the spectra of the filled and unfilled styrene- butadiene rubber (SBR). These changes are attributed to ...

Molecular Aspects of Tack

JUN 1984

Authors: R. P. Wool; ILLINOIS UNIV AT URBANA DEPT OF METALLURGY AND MINING ENGINEERING

Scanning Photoacoustic Microscopy of Aluminum with Aluminum Oxide, Roughness Standards and Rubber

JUN 1984

53 pages

Authors: R. L. Thomas; L. D. Favro; P. K. Kuo; D. N. Rose; D. Bryk; WAYNE STATE UNIV DETROIT MI

Thermal wave imaging of coated samples, surface geometries of homogeneous samples, and dispersed particles in rubber samples are presented and discussed. Preliminary results of color-encoding of images are encouraging. Further photothermal (infrared radiation) detection studies of the coated graphite samples are recommended, along with more detailed study of numerical analysis of surface roughness applications. Preparation of rubber samples containing layer defects is also recommended.

Military Engineering Exhibition by Pirelli Group of Italy

11 APR 1984

11 pages

Authors: M. Zhu; FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH

A review of various products of the Pirelli Group of Italy, displayed at an exhibition, which have military battlefield, applications is presented. Products described include: fiberglass cloth protective suits with activated carbon to adsorb nuclear radiation, and biological and chemical agent contaminants; underground shelters and storage tanks with vulcanizates or elastomers as liners and insulation for shielding against blast shocks; self sealing fuel tanks; and tire cord for combat vehicles. ...

Nitrile Elastomer Treating Solution and Method of Treating Nitrile Elastomer Therewith.

10 APR 1984

Authors: Martin H. Kaufman; DEPARTMENT OF THE NAVY WASHINGTON DC

A method of preparing nitrile elastomer surfaces for bonding by epoxy adhesives is presented. A treating solution comprising a dilute concentration of a mineral acid such as HCL in a carrier comprising water and either alcohol or ketones is prepared. The treating solution is applied to the elastomer surface with the surface being hydrolyzed in a mild manner therby providing an improved adherable surface for covalent bonding by epoxy adhesives. ...

Rubber to Backing Bond Strength for Stave Bearings

APR 1984

Authors: T. L. Daugherty; DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD

Rubber-surfaced stave bearings in most U.S. Navy ships support the propulsion shafting and propeller aft of the main shaft seal. Problems have been encountered with inadequate bonding of the rubber surface to their brass backing and with corrosion of the brass backing. The objective of this work was twofold: to develop improved specification criteria that would ensure reliable bonding between the rubber surface and the backing, and to evaluate the ...

The Role of Chemical Bonding in Adhesion

APR 1984

Authors: A. N. Gent; P. Dreyfuss; AKRON UNIV OH INST OF POLYMER SCIENCE

Work during the period from March 1, 1983 to February 29, 1984 has been focussed in two main categories, namely, studies of basic failure processes in elastomeric materials and studies of factors affecting the adhesion of various materials to each other. These studies are summarized in this report which describes eight technical reports, 6 publications, and 4 technical presentations made during the year.

Synthesis and Investigation of Polyimidobenzimidazoles

29 MAR 1984

Authors: N. P. Lyubchenko; B. A. Zhubanov; FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH

Effect of Interfacial Bonding on the Strength of Adhesion of Elastomers. III. Interlinking by Molecular Entanglements

FEB 1984

Authors: A. N. Gent; R. H. Tobias; AKRON UNIV OH INST OF POLYMER SCIENCE

Polydimethylsiloxane (PDMS) networks have been formed by endlinking linear PDMS molecules. When second layer is cast on top of a fully-gelled lower- layer, the new molecules diffuse into the surface of the lower layer and form molecular loops ('entanglements') in the course of endlinking with themselves. The two layers are then joined only by the macromolecular loops. Measurements have been made of the work required to separate such layers under ...

Micromechanics of Fracture in Elastomers

FEB 1984

33 pages

Authors: A. N. Gent; C. T. R. Pulford; AKRON UNIV OH INST OF POLYMER SCIENCE

A study of torn surfaces and of the tips of propagating tears in elastomers has been carried out using scanning electron microscopy. Vertical steps separating smooth featureless torn regions are characteristics features of the torn surfaces. They are found to be more frequency and larger in stronger elastomers. They are attributed to the intersection of secondary cracks at the tear tip, displace somewhat from the general tear plane, and nucleated ...

Peroxide Cross-Linked Natural Rubber and Cis-Polybutadiene: Characterization by High-Resolution Solid-State Carbon-13 NMR

1984

Authors: D. J. Patterson; J. L. Koenig; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE

Diffusive Fronts of Penetrants in Glassy Polymers

Authors: D. S. Cohen; CALIFORNIA INST OF TECH PASADENA DEPT OF APPLIED MATHEMATICS

In this paper we derive and present a model which incorporates and unifies many of the diverse observations occurring in diffusive motion in glassy polymers. Our model explicitly incorporates the most important property of a glassy polymer, namely the finite relaxation time implied by the slow response to changing conditions. While this slow response property of a glassy polymer is recognized by all researchers, almost all other models do not ...

Development of Criteria for the Use of Asphalt-Rubber as a Stress- Absorbing Membrane Interlayer (SAMI)

DEC 1983

Authors: D. E. Newcomb; R. G. McKeen; NEW MEXICO ENGINEERING RESEARCH INST ALBUQUERQUE

This report documents over 2 years of research efforts to characterize asphalt-rubber mixtures to be used in Stress-Absorbing Membrane Interlayers (SAMI). The purpose of these SAMIs is to retard or prevent reflection cracking in asphalt-concrete overlays. Several laboratory experiments and one field trial were conducted to define significant test methods and parameters for incorporation into construction design and specification documents. Test methods used in this study included a modified softening ...

Mechanical Properties of Silicone Rubber in a Closed Volume

DEC 1983

21 pages

Authors: G. P. O'Hara; ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER WATERVLIET NY LARGE CALIBER WEAPON SYSTEMS LAB

This report covers an experiment to measure the mechanical properties of four samples of RTV silicone rubber. The test was conducted under conditions of small strains and an elevated hydrostatic pressure component of stresses (0 - 4000 psi). The results gave a Young's modulus in the range of 13,000 to 21,000 and a Poisson's ratio range of 0.48 to 0.49. The young's modulus values were much higher than the usual ...

Rubber Compound Development for Improved Military Tank Track. Phase I

DEC 1983

Authors: M. B. Hoying; GOODYEAR TIRE AND RUBBER CO ST MARYS OH

Ten each T-156 blocks were prepared from six different experimental compounds for analysis by TACOM. The compounds were formulated without regard for the requirements of Mil-T-11891B. These six compounds were chosen after laboratory testing of over 110 experimental formulations.

Vulcanization Studies of Elastomers Using Solid-State Carbon-13 NMR

DEC 1983

Authors: D. J. Patterson; J. L. Koenig; J. R. Shelton; CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE

Effect of Pressure on the Static and Dynamic Acoustic Properties of Porous Rubber

01 OCT 1983

Authors: G. C. Gaunaurd; E. Callen; J. Barlow; NAVAL SURFACE WEAPONS CENTER SILVER SPRING MD

In this report we analyze the effects of pressure on the acoustic properties of porous rubbers. We consider the static and dynamic bulk moduli, the velocities of dilatational and shear waves, the characteristic wave impedances, the fundamental frequency of the monopole resonance, and the frequency dependence of the effective sound speed and attenuation. A series of figures at the end of the report shows how the (static) acoustic properties vary ...

Preparation and Properties of Polyurethane and Polyurethaneurea Elastomers from Methylene Bis(4-Cyclohexylisocyanate)

OCT 1983

Authors: C. A. Byrne; E. A. McHugh; R. W. Matton; M. A. Cleaves; D. P. Mack; ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MA

Transport polyurethane elastomers have been prepared and evaluated as flexible lens materials. The main ingredients of the polymers include methylene bis(4-cyclohexylisocyanate), poly(tetramethylene oxide) polyols, and 1,4-butane- diol, with small amounts of ethylene glycol and trimethylol propane added to improve properties. The polymers exhibit very good mechanical properties for the desired use, however, the low temperature (-20 C) bend recovery needs to be improved. Additional problems include the lack of a ...

Elastomeric Seal.

13 SEP 1983

Authors: Fred B. McCarty; Christopher M. Gibson; DEPARTMENT OF THE AIR FORCE WASHINGTON DC

This document describes an elastomeric bore seal, and a method of making andinstalling it. The seal is a fluid-impervious, thin-walled (0.025 inch), open-ended, cylinder-like member which is made of an expansible material that can withstand a wide range of temperatures (-65 F. to +400F.) and that is to be bonded and thereby installed. The use of the seal is a bore seal in an electrical machine not only provides an ...

Effects of Fuels on the Physical Properties of Nitrile Rubber O-Rings

SEP 1983

Authors: J. R. Coleman; L. D. Gallop; DEFENCE RESEARCH ESTABLISHMENT OTTAWA (ONTARIO)

The effects were studied of containing nitrile O-rings with a variety of fuels and fuel blends. Properties (tensile strength, elongation, swelling) depended markedly on the aromatic content. When O-rings were cycled between fuels of low and high aromatic content, these properties took up values characteristic of the fuel in which the sample was currently immersed. Rubber samples were exposed to a commercial fuel (gas oil side stream) of high (greater ...

Fuel System O-Ring Leaks on Post P.D.M. (Programmed Depot Maintenance) C-5A Aircraft

SEP 1983

Authors: C. J. Forzono; SAN ANTONIO AIR LOGISTICS CENTER KELLY AFB TX DIRECTORATE OF MATERIEL MANAGEMENT

This report presents the data developed and gathered as a result of fuel leaks around O-rings found in C-5 fuel systems following long periods of Programmed Depot Maintenance (PDM). The O-ring leaks occured when the fuel system was refilled after having been empty for 60-90 days during PDM. The study also involved an investigation of Buna-N O-ring shrinkage and swelling characteristics along with some testing of less or no shrinkage ...

Seamless Collapsible Fuel Tanks

JUL 1983

Authors: Norman J. Abbott; Robert E. Erlandson; ALBANY INTERNATIONAL RESEARCH CO DEDHAM MA

Twenty-Three by twenty foot (lay flat) pieces of tubular fabric was coated with polyurethane and fabricated into two 7500-gallon fuel tanks. The tanks were shipped to Arizona for filling and exposure testing. (Author)

1982 Inspection of Experimental Marine Piling at Pearl Harbor, Hawaii

JUL 1983

Authors: Thomas B. O'Neill; NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA

The Navy is considering alternative wood preservatives that are environmentally acceptable. In order to determine the effectiveness of wood preservatives in the marine environment, the Naval Civil Engineering Laboratory (NCEL), in cooperation with industry, installed pilings with test preservatives in Pearl Harbor, Hawaii, in 1963 through 1966 and has observed and evaluated the preservatives. Certain chemicals, such as the chlorinated hydrocarbons, chlordane, and dieldrin, have demonstrated outstanding presersvative qualities; the ...

Inspection of Sonar Dome Rubber Windows Using Collimated Photon Scattering

JUN 1983

Authors: Nicholas Vagelatos; Dale D. Thayer; Kenneth Brown; Frederic N. Howe Jr; IRT CORP SAN DIEGO CA

Laboratory measurements have been performed on a test piece of sonar dome rubber window (SDRW) which demonstrate the feasibility of using the collimated photon scattering (CPS) technique to detect and measure defects, especially voids, in SDRW. The CPS technique was originally identified by IRT as a powerful industrial inspection method for certain nondestructive evaluation tasks about eight years ago and has since been successfully implemented by IRT in industrial inspection ...

Forced Vibration of Timoshenko Beams Made of Multimodular Materials

JUN 1983

Authors: F. Gordaninejad; C. W. Bert; OKLAHOMA UNIV NORMAN SCHOOL OF AEROSPACE MECHANICAL AND NUCLEAR ENGINEERING

This paper presents a transfer-matrix analysis for determining the sinusoidal vibration response of thick, rectangular-cross-section beams made of multimodular materials (i.e., materials which have different elastic behavior in tension and compression, with nonlinear stress-strain curves approximated as piecewise linear). An experimentally determined stress-strain curve for aramid- cord rubber is approximated by four straight-line segments (two segments in tension and two segments in compression). To validate the transfer-matrix results, a closed-form ...

Engineering and Development Support of General Decon Technology for the DARCOM Installation Restoration Program. Task 1. Lagoon/Landfill Liner Compatibility Testing with Explosives

JUN 1983

Authors: Gregory M. Gibbons; Jonathan W. Braswell; ENGINEERING-SCIENCE FARIFAX VA

This report presents the results of liner compatibility screening tests with TNT, RDX and TCE. Using the NSF Liner Compatibility Screening Tests, eight types of liners (PVC, PVC-OR, CPE, Hypalon, XR-5, HDPE, Neoprene, and EPDM) were immersed in TNT, RDX, and TCE solutions for 1 week. Liner and test method selection and data analysis for the screening test are presented. (Author)

Fracture Mechanics Applied to Elastomeric Composites

APR 1983

Authors: A. N. Gent; AKRON UNIV OH INST OF POLYMER SCIENCE

Griffith introduced a general fracture criterion in 1920: a crack will grow only when enough energy is available in the system to cause further fracture. This simple concept has been applied to various tear processes in elastomeric materials by Rivlin and Thomas and to a variety of adhesive failures by Kendall. Their results are reviewed, with particular reference to the fracture and debonding of elastomeric composites. Two further cases are ...