Factbites
 Where results make sense
About us   |   Why use us?   |   Reviews   |   PR   |   Contact us  

Topic: Bond strength


Related Topics

In the News (Mon 6 Jul 09)

  
  Strengths of Covalent Bonds   (Site not responding. Last check: 2007-10-25)
The stability of a molecule is a function of the strength of the covalent bonds holding the atoms together.
The bond energy for a given bond is influenced by the rest of the molecule.
However, this is a relatively small effect (suggesting that bonding electrons are localized between the bonding atoms).
wine1.sb.fsu.edu /chm1045/notes/Bonding/Strength/Bond09.htm   (320 words)

  
 ChemViz Determination of Pi Bond Strength in the Ethene Molecule Lab
In this lab the pi bond strength in the ethene molecule is determined by optimizing the carbon-carbon bond length during this transition.
Rotation of one carbon atom of the double bond in the ethene by ninety degrees breaks the pi bond; this in turn allows a relaxation and a subsequent increase in the bond length during this transition.
In this lab the bond length of C-C bond is increased, consistent with the loss of the pi bond attraction between the carbon atoms, at 1.34 and 1.46 Ångstrom units.
chemviz.ncsa.uiuc.edu /content/lab-s-pibond.html   (729 words)

  
 Composite material having improved bond strength - Patent 4429022
As previously indicated, the metallurgically bonded composite is obtained by rolling together the core and cladding in strip form in a single pass with a reduction of from about 50 to about 75% and thereafter subjecting the bonded core and cladding to a heat treatment at a temperature in the range of about 200.degree.
The problem of low bond strength is believed to be the result of several factors including long continuous grain boundary cracks, a layer of detritus at the interface, and degradation of the interface as the result of residual oxygen in the core material.
The bond strength of the C15100-containing composite was substantially retained with cold rolling after the anneal, whereas the bond strength of the C11000-containing composite was reduced significantly.
www.freepatentsonline.com /4429022.html   (4315 words)

  
 SparkNotes: Properties of Chemical Bonds: Properties of Chemical Bonds
Therefore, it is sensible to define bond strength as the amount of energy needed to break a chemical bond.
Trends in bond strength show that homoatomic bonds (those formed between atoms of the same element) tend to be strong.
Bond lengths follow the expected trend that bonds between larger atoms are longer and bonds between smaller atoms are smaller.
www.sparknotes.com /chemistry/bonding/properties/section1.html   (779 words)

  
 2-Cyanoacrylate adhesive compositions having enhanced bond strength - Patent 4139693
Adhesive compositions having enhanced bond strength are obtained by mixing a monomeric ester of 2-cyanoacrylic acid with an anionic polymerization inhibitor and from 1 to 30 mmoles per kg.
Although adhesive compositions consisting of 2-cyanoacrylate esters and conventional stabilizers inherently yield high bond strength (as commonly measured by the test of tensile shear strength), improvements therein would be desirable particularly in cases where the substrate is of greater strength than the adhesive, as in the case of many metal bonds.
The bond strength, or tensile shear strength, is determined by pulling the bars apart with an Instron Tensile Tester at a crosshead operation speed of 0.254 cm./min.
www.freepatentsonline.com /4139693.html   (4273 words)

  
 Bond Strength in Battened Composite Columns   (Site not responding. Last check: 2007-10-25)
Several factors believed to affect the bond between the two materials are investigated, including age and size of specimen, curing, and temperature.
The strength of bond at the age of one year is about 30% of that at the age of three weeks.
The size of the specimen, which affects the shrinkage and the confinement of the concrete, proves to be a significant factor of bond reduction.
www.pubs.asce.org /WWWdisplay.cgi?9100448   (169 words)

  
 bond strength - Parkell, Inc.
You see, bonding studies are based on the assumption that there’s a correlation between tensile bond or shear bond strength and clinical success.
There’s considerable research showing that bond strength varies significantly according to the specific tooth you’re bonding to.* Third molars may not be representative.
This means that a rank-order of adhesives according to their bond strength might change if the researcher simply used a different test technique.
www.parkell.com /bondstrength.html   (1417 words)

  
 Testing Data - Bond Strength
Bond Strength test were performed on samples with and without ABC Fibers.
The goal of the bond strength test is to determine if the addition of ABC Fibers to concrete adversely affects the bond strength between the concrete and the primary reinforcement.
The conditions for acceptance are that the average bond strength for the steel reinforcement embedded in the concrete with the fibers must be equal to the average bond strength in the control sample.
www.abcpolymerindustries.com /bs.shtml   (304 words)

  
 Hydrogen Bond Encyclopedia Article @ BondsTrade.com (Bonds Trade)   (Site not responding. Last check: 2007-10-25)
The length of hydrogen bonds depends on bond strength, temperature, and pressure.
When more molecules are present, as is the case in liquid water, more bonds are possible because the oxygen of one water molecule has two lone pairs of electrons, each of which can form a hydrogen bond with hydrogens on two other water molecules.
molecular geometry of these complexes are similar to hydrogen bonds, in that the bond length is very adaptable to the metal complex/hydrogen donor system.
www.bondstrade.com /encyclopedia/Hydrogen_bond   (1555 words)

  
 Chemical bonding: introduction
A chemical bond is so often represented as a line drawn between atom symbols or a stick connecting two balls in a plastic molecular model that we sometimes tend to think of chemical bonds as “things”.
Chemical bonding connotes the existence of an aggregate (assembly) of atoms that is sufficiently stable to possess a characteristic structure and composition.
Bond lengths depend mainly on the sizes of the atoms, and secondarily on the bond strengths, the stronger bonds tending to be shorter.
www.chem1.com /acad/webtext/chembond/cb01.html   (2737 words)

  
 Refrigeration and tensile bond strength
After the tensile bond strength tests, the fractured surfaces of the specimens were visually examined with a stereomicroscope (Olympus Corp., Tokyo, Japan) at X20 to classify the type of failure that occurred during the debonding procedure.
Another theoretical disadvantage of refrigeration, the decrease in bond strength due to the adverse effect of refrigeration upon the physical properties of the adhesive materials, seems not to have occurred, because little or no effect could be detected in the bond strength under refrigerated conditions.
In the shear bond tests, there is a tendency for cohesive failures to occur in dentin due, in part, to the mechanism of the test (18).
www.forp.usp.br /bdj/bdj12(2)/trab01122/trab01122.html   (2920 words)

  
 World Dentistry | Long-Term Resin Bond Strength to Zirconia Ceramic   (Site not responding. Last check: 2007-10-25)
The purpose of this study was to evaluate the long-term bond strength of YPSZ ceramic via certain resin cements.
The bond strength of group T and ST was initially very low (14.2 MPa and 13.9 MPa, respectively) and both groups debonded spontaneously during the 2-year storage time.
Due to the fact that the failure modes of P and P21 were completely cohesive, the decrease in bond strength is attributed to a degradation of the resin itself and not to its bond with the ceramic.
www.worlddent.com /2001/05/journal.reviews/jad-2000-2-139-146.xml   (717 words)

  
 Bond strength - Wikipedia, the free encyclopedia
In chemistry, bond strength is measured between two atoms joined in a chemical bond.
Bond strength is intimately linked to bond order.
Another criterion of bond strength is the qualitative relation between bond energies and the overlap of atomic orbitals of the bonds (Pauling and Mulliken).
en.wikipedia.org /wiki/Bond_strength   (149 words)

  
 Medical Devices — Adhesive Applications - Bondmaster
Bondmaster needle bonding adhesives secure the cannula byuniformly filling the gap between the hub wall and the needle.
Bondmaster needle bonding adhesives can be formulated with multiple viscosities to allow the use of different gauge cannulae within a standard hub.
Bond length must also be considered if the hub is constructed of bond-resistant materials like polypropylene.
www.bondmaster.com /medicalApps.asp   (850 words)

  
 AATCC Test Method 136, Bond Strength of Bonded and Laminated Fabrics   (Site not responding. Last check: 2007-10-25)
Bond strength tests can be made on the fabric as bonded or laminated or after a specified number or drycleaning and/or laundering cycles.
2.1 Bond strength tests can be made on the fabric as bonded or laminated and subsequently drycleaned, or laundered and dried, or both, through a prescribed cycle that is repeated a specified number of times.
The drycleaned or washed specimens are tested to determine the strength of the bond.
www.aatcc.org /Technical/Test_Methods/scopes/tm136.cfm   (136 words)

  
 Destructive and Non   (Site not responding. Last check: 2007-10-25)
Two tests are industry standards for establishing wire bond strength and the acceptability of part lots based on that bond strength.
For cases where the die and the substrate bonds are at equal height (θ = 0 in Figure X below), or very flat, the pulling force is applied, by using a hook, approximately in the center of the wire in a direction normal to the die or substrate.
If the bonds are not equal height, the bond pull shall be performed where the bend (loop) is formed between the two bonds.
nepp.nasa.gov /wirebond/destructive_and_non.htm   (875 words)

  
 Slick Bricks - Properties, Accessories and Certifications of Slick Bricks - Austral Bricks Australia   (Site not responding. Last check: 2007-10-25)
Bond strength is a good indication of the overall robustness of a masonry wall.
Bond is influenced by many factors including the suction of the masonry unit, the water retention of the mortar, the ingredients of the mortar and any additives used.
Mortar is relatively weak compared to clay bricks, so that the removal of the mortar increases the masonry strength as shown in the results achieved with Slick Bricks in Table 2.
www.azom.com /details.asp?ArticleID=2164   (819 words)

  
 Bond strength - Parkell, Inc.
The big fib is that those bond strength numbers published in literature have some kind of clinical significance.
Bond strength data for a particular bonding agent can vary wildly from study to study.
By a "good quality bond" they mean the adhesive resin has penetrated all the way through the collagen on the surface of the preparation and encapsulated crystals of hydroxyapatite below.
www.parkell.com /article5.html   (2677 words)

  
 Master Bond Products by Type
Their most desirable properties include high bond strength to a wide variety of different substrates, outstanding gap filling capabilities, excellent electrical insulation, high chemical inertness and outstanding resistance to shock and vibration.
Master Bond elastomeric contact cements are formulated with a variety of synthetic and natural rubbers and special thermosetting resins.
The Master Bond product line includes polysulfide/epoxy alloys which combine the well known adhesive strength properties of epoxy resins with the inherent flexibility of polysulfides to produce a truly unique family of tough, chemically resistant, high strength materials with a wide range of carefully controlled performance characteristics.
www.masterbond.com /prodtype.html   (1559 words)

  
 CiteULike: Dynamic strength of molecular adhesion bonds.   (Site not responding. Last check: 2007-10-25)
To examine what can be learned from measurements of bond strength, we have extended Kramers' theory for reaction kinetics in liquids to bond dissociation under force and tested the predictions by smart Monte Carlo (Brownian dynamics) simulations of bond rupture.
By definition, bond strength is the force that produces the most frequent failure in repeated tests of breakage, i.e., the peak in the distribution of rupture forces.
First, bond strength emerges at a critical rate of loading (> or = 0) at which spontaneous dissociation is just frequent enough to keep the distribution peak at zero force.
www.citeulike.org /user/ruudvanleeuwen/article/463297   (874 words)

  
 S-Bond Technologies LLC
The bonded layer at the substrate surface will not be affected, so good interfacial bond strength is maintained and re-activation is not required.
The bonding strength to both titanium and stainless steel can be improved by use of our proprietary process to covalently bond our materials to the metal surface.
The joint strengths are generally lower than metal-to-metal bonds, and the structures vary with the substrate materials.
www.s-bond.com /technology.htm   (2100 words)

  
 15.9
The polarity of a X—H bond increases with the electronegativity of the nonmetal atom.
The importance of bond polarity in determining acid strength outweighs that of atomic radius.
This increases the polarity of the O—H bond.
www.mhhe.com /physsci/chemistry/chang7/ssg/chap15_9sg.html   (752 words)

  
 Chapter 8 - Bond Length, Strength & Order
In a molecule as you increase the number of electrons shared between two atoms, you increase the bond order, increase the strength of the bond, and decrease the distance between nuclei.
We experimentally measure bond lengths using x-ray and neutron diffraction, which was mentioned briefly in chapter 6.
Then remember to multiply the number of bonds in each molecule by the coefficient in front of the molecule.
www.chemistry.ohio-state.edu /~woodward/ch121/ch8_bondorder.htm   (411 words)

  
 Applications: transport - From Research to Reality - Bondmaster Knows Transport Assembly
Whether your application is bonding stress panels, external panel work, or honeycomb panels, Bondmaster's experience in formulating panel bonding adhesives can help bring a new product to market faster, or even reduce an existing product's cost of production.
If the zinc coating is not properly analyzed, poor bonds will result due to inaccurate formulation of the adhesive relative to the thickness of the zinc coating.
Because the final strength of the bond often depends on the adhesion of the zinc coating, Bondmaster's transport adhesives have been developed to interact with the zinc itself to strengthen the bond rather than resist it like many commodity adhesives.
www.bondmaster.com /transportApps.asp   (732 words)

  
 The Zone : From the inside, Howdt: Nature of the Chemical Bond IV : Bond Strength
The other type, the covalent chemical bond involves a sharing of the electrons by both partners elevating their control status to eight by pairing otherwise unshared electrons into hybridized overlapping orbitals.
When it pairs to make carbon-carbon double bonds with bond order two, the second overlapping bond turns up in an antibonding orbital causing high reactivity.
Orbital for the carbon-carbon double bond are somewhat different from the orbital for the oxygen-oxygen double bond.
www.howdt.com /blog/2006/06/nature-of-chemical-bond-iv-bond.html   (734 words)

  
 SparkNotes: Ionic Bonds: Ionic Bonding
As we shall explore in this section on ionic bonding, ionic bonds result from the mutual attraction between oppositely charged ions.
They tend to be stronger than covalent bonds due to the coulombic attraction between ions of opposite charges.
Bond strength, it will be shown, depends mostly on the charges present on each ion and the distance between them.
www.sparknotes.com /chemistry/bonding/ionic/summary.html   (205 words)

  
 Master Bond Polymer System X17 Product Description
Master Bond Polymer System X17 is a specially formulated one component adhesive especially designed for bonding polyolefins such as polypropylene, polyethylene as well as their many co-polymers and blends.
Bond strength increases sharply as evaporation of the solvent progresses and with some adherents it might approach the strength of the substrate materials.
Maximum bond strength is obtained upon complete evaporation of the solvent.
www.masterbond.com /tds/x17.html   (416 words)

  
 Portable Wire-Bond Strength Tester
These features assure the repetitive read-out accuracy that is essential in wire bond testing—but which is impossible with other testers.
(The Wire-Bond Strength Tester is designed for use with most standard wire bond chucks; the magnetic accessory chuck is suitable for most applications.) Next, you position the pull hook under the wire to be tested with the aid of a microscope (not included).
Because the wire-loop heights of finished bonds are within close tolerances, this limited force testing can be performed with sufficient accuracy to ensure that wire bonds are good.
www.terrauniversal.com /products/tweezers/portablewiretest.php   (536 words)

Try your search on: Qwika (all wikis)

Factbites
  About us   |   Why use us?   |   Reviews   |   Press   |   Contact us  
Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.