ASTM – ASTM American Society for Testing and Materials.

ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services.

List of ASTM International standards:

• A = Iron and Steel Materials.
• B = Nonferrous Metal Materials.
• C = Ceramic, Concrete, and Masonry Materials.
• D = Miscellaneous Materials.
• E = Miscellaneous Subjects.
• F = Materials for Specific Applications.
• G = Corrosion, Deterioration, and Degradation of Materials.

ASTM is a national organization that is a part of ISO organizations. ISO is an international organization that has representations from all countries including ASTM. ISO establishes documents and updates the standards of testing materials with global consensus from the experts of the associated national organizations.

ABRASION RESISTANCE – Abrasion resistance is the ability of materials to withstand the effects of abrasion, for example: repeated wearing, rubbing, scrapping, etc.

Abrasion-resistant materials are handy in inhibiting mechanical wearing and damage. They can be used in the construction of space shuttle components. The abrasion resistance of high-performance concrete is high. This concrete containing silica-fume is useful for concrete pavement overlays where heavy or abrasive traffic occurs more.

Abrasion resistance is a property that allows a material to resist wear. The abrasion resistance of a material helps to withstand mechanical action and tends to protect the removal of materials from its surface. This allows the material to retain its integrity and hold its form. This can be important when the form of a material is critical to its function, as seen when moving parts are carefully machined for maximum efficiency. Abrasion resistance can be measured by using the abrasion scrub tester.

Abrasion resistance can be controlled through:

• Using proper lubricants
• Covering items with an abrasion-resistant material
• Controlling the cause of abrasion
• Utilizing abrasion-resistant coating

In rubber, there are two types of abrasion:

1. Sliding – the passing of an adjacent surface across the rubber surface.
2. Impingement – wearing of the rubber exemplified by sand particles hitting the surface.
   When the rubber cannot withstand localized friction forces, abrasion and wear takes place.

ABRASION RESISTANCE INDEX – The resistance to abrasion can be expressed in several ways, the most common are the weight loss (in mg) per number of cycles or the number of cycles (per unit of film thickness) needed to wear through.

ACCELERATED AGING – The Accelerate Aging test simulates real-time aging using elevated temperatures to artificially speed up the aging process. This test enables manufacturers to get their product to market faster. Accelerated aging is optional, but real-time aging is required when establishing an expiration date.

The Accelerate Aging test simulates real-time aging using elevated temperatures to artificially speed up the aging process. This test enables manufacturers to get their products to market faster. Accelerated aging is optional, but real-time aging is required when establishing an expiration date. Often, referred to as Accelerated Shelf-Life Testing – is commonly used in the medical device industry to accelerate the effects of time on a Sterile Barrier System to establish Shelf Life parameters. The Accelerated Aging process is based on the relationship of temperature and reaction rate where an increase in temperature increases the reaction rate.

ACCELERATOR – Accelerants are substances that can bond, mix or disturb another substance and cause an increase in the speed of a natural, or artificial chemical process. Chemical accelerators are used in glove manufacturing to hasten the linkage of molecules in natural rubber latex or in synthetic rubber latex-like nitrile and vinyl. The accelerants transform the liquid materials into thin, strong, and elastic glove films. Accelerator, in the rubber industry, any of numerous chemical substances that cause vulcanization (q.v.) of rubber to occur more rapidly or at lower temperatures. Many classes of compounds act as accelerators, the most important being organic materials containing sulphur and nitrogen, especially derivatives of benzothiazole.

The use of alkaline compounds of metals as vulcanization accelerators was cited in the original patent of the vulcanization process, granted to Charles Goodyear in 1844; magnesium oxide, zinc oxide, and basic lead carbonate were used until early in the 20th century, when the superiority of aniline, an organic compound, was discovered. Despite its toxicity, aniline was used as an accelerator for several years. Thiocarbanilide, less poisonous than aniline, succeeded it as the most important accelerator until it was displaced by mercaptobenzothiazole (MBT) about 1925. Compounds related to MBT have proved especially useful in vulcanizing synthetic rubbers.

During vulcanization, the accelerator apparently converts the sulphur into a compound that reacts more rapidly with rubber than does sulphur itself. An alternative possibility is that the accelerator reacts first with the rubber, changing it into a form that combines rapidly with sulphur.

ACRYLATE RUBBER: acrylate is (organic chemistry) any salt or ester of acrylic acid, Acrylates have found application in the manufacture of co-polymers for coatings and paints, sealants, adhesives, textile fibres, printing inks. It is highly superabsorbent polymers and thus used in diapers. Thermoplastic acrylate co-polymers, in biomedicine and a variety of other advanced application areas.

Acrylate polymers are a group of polymers prepared from acrylate monomers. … They are also commonly known as acrylics or polyacrylates. Acrylate polymer is commonly used in cosmetics, such as nail polish, as an adhesive.

ACRYLIC RUBBER – Acrylic rubber is a copolymer or terpolymer of ethyl acrylate and other acrylates, with a small amount of a vulcanisation-supporting monomer. It is produced by radically initiated emulsion polymerisation or by suspension polymerisation. Curing takes place by means of diamines, fatty acid soaps and peroxides, for example.

ACM is characterised by high oxygen and ozone resistance, thermal stability and good heat and chemical resistance, but it has poor hydrolysis resistance and relatively high-water absorption.

The swelling resistance in the presence of mineral oils is better than that of ethylene acrylic rubber (AEM/Vamac®).

Acrylic rubber is mostly used in the automotive industry because it is resistant to engine and transmission oil and to automatic transmission fluids (ATF). The operating temperature range is between -20°C and +150°C, while the latest generation, HT-ACM (high-temperature-resistant polyacrylate elastomers), offers long-term thermal stability up to 175°C. ACM is used to manufacture components such as engine and transmission seals, turbocharger hoses, O-rings, diaphragms and hose applications. It is also used for roller coverings.

ACRYLONITRILE – acrylonitrile toxic colourless liquid organic compound, CH=CH.CN, synthesized from propylene and ammonia; used as a monomer in the production of acrylic resins and synthetic rubber.

Acrylonitrile is manufactured by combining propylene, ammonia, and air in a process called ammoxidation. During ammoxidation, propylene, ammonia and air are fed through a catalyst at a high temperature.

Acrylonitrile is used in many industries.

It is used to make certain plastics, rubbers, and chemicals, and in the past, as a pesticide. Some examples of workers at risk of being exposed to acrylonitrile include the following: Workers involved in the manufacturing of acrylic fibers and plastics.

ACTIVATOR – Activator may refer to: Activator (genetics), a DNA-binding protein that regulates one or more genes by increasing the rate of transcription. Activator (phosphor), a type of dopant used in phosphors and scintillators. Enzyme activator, a type of effector that increases the rate of enzyme mediated reactions.

Use as an activator:

• BORAX POWDER. Borax powder is the most widely known of the slime activators and contains borax or sodium tetraborate
• SALINE SOLUTION. This is our number one favorite on the slime activator list because it makes an awesome stretchy slime
• LIQUID STARCH
• EYE DROPS OR EYE WASH

ADHESION: adhesion is the tendency of dissimilar surfaces to stick to one another. It can be measured in terms of work of adhesion in J/m2. It is the energy needed to separate 1m² of joined materials. It can also be measured as peel in N/m, which is the force required to pull off a strip of material that is 1 meter wide.

Thus, the two measures are identical: 1 J/m2 equals 1 N/m.

It is believed that surface energy is important for adhesion. However, an increase in surface energy does not necessarily improve adhesion, that is, the energy that is required to separate a (viscoelastic) polymer from a surface (often called work of adhesion) is not directly proportional to the surface tension. This can be easily shown: The typical surface energy of a polymer is in the range of 20 to 40 dyne/cm or 40 mN/m, whereas typical peel values are in the range of a 20 to 1000 N/m. Therefore, adhesion forces are at least 100 times and typically 10,000 times stronger. Thus, surface tension plays only a minor role for adhesion contrary to what is often believed. However, surface tension and wetting is still important when it comes to initiating adhesion.

So, what is the root cause of adhesion?

In fact, there are many types of forces that can occur when surfaces come in close contact:

1.  MECHANICAL ADHESION
   The adhering polymer (adhesive) flows into the voids / pores of the substrate and thus interlocks with the micro-porosity like pieces of puzzles. If the liquid hardens, as it is the case with structural adhesive, a strong bond is formed between the substrate and the adhesive.
2. NON-SPECIFIC OR DISPERSIVE ADHESION
   Dispersive adhesion is caused by rather weak non-specific intermolecular forces (Van der Waals Forces) which are present in all materials. These attractive forces originate from induced dipole – induced dipole interactions between uncharged atoms and molecules and are the main cause of cohesion in condensed matter (liquids and solids).
3. ELECTROSTATIC ADHESION
   Electrostatic adhesion is based on the formation of an electrical double layer when two materials come in contact and exchange electrons. This creates an attractive electrostatic or Coulomb force between the two materials similar to the two plates of a capacitor.
4. SPECIFIC ADHESION
   Specific adhesion occurs when the atoms/molecules of the two adhering surfaces form specific bonds such as hydrogen bonds. These forces are responsible for the high boiling point of low molecular weight liquids with strong dipoles such as water, glycerin, methanol and so on.
   Another specific adhesion force at the surfaces is acid-base interaction which includes Lewis donor-accepter, and Bronsted acid-base interactions. The acid-base theory suggests that adhesion forces are the result of electron (proton) donation and acceptance between acids and bases.
5. CHEMICAL ADHESION
   Chemical adhesion is a special case of specific adhesion. The atoms/molecules of the two adhering materials form chemical bonds that can be of ionic or covalent character. This is usually the strongest form of adhesion. Since polymers adhere to a substrate at multiple sites along the chain, the force of adhesion is typically much stronger than that of the corresponding monomer.
6. DIFFUSION ADHESION
   Some materials may fuse at the joint by diffusion. This happens when the two polymeric materials are soluble in each other and mobile enough to interdiffuse. The phenomenon is known as interdiffusion or interpenetration. Even modest “intermingling” of the polymers of the two plastic substrates can lead to noticeable adhesion and if the polymers truly “entangle”, when they cross the interface, strong adhesion will occur due to physical crosslinking (entanglement).

ADHESION FAILURE – When separating adhering materials, two types of failure can occur. In the case of adhesive failure, the bonds between the adhesive and adherend break, i.e., no contaminations from the adhesive and adherend remain on the separated surfaces. This is the preferred failure mode for pressure sensitive adhesive tapes. In the case of cohesive failure, the fracture appears within either the adhesive or adherend. This is the preferred failure mode for structural adhesives.

Adhesion failure refers to the state when the adhesive loses adhesion from one of the bonding surfaces. It is characterized by the absence of an adhesive on one of the material surfaces. Surface treatment is required to fix this failure.

Understanding this state requires a careful analysis of adhesive failures. The failure may be located at the bonding interface with a very thin layer. This interface may be contaminated during surface preparation of the adherend surface and while applying an adhesive.

Adhesion failure happens at the interface between the adhesive layer and the adherends. This failure results from the hydration of the chemical bonds, which form the connection between the adhesive and the bonding surface. An adhesive bond fails when either the adhesive loosens from the substrate or when the adhesive breaks apart.

Adhesion failure is mainly substrate adhesion failure and inter coat adhesion failure. Substrate adhesion failure occurs when the whole coating system that has been used for bonding can be easily detached from the substrate. It shows the absence of adhesion of the whole coating system that has been applied. Causes of this failure are linked to three things:

• Inadequate or non-existent blast profile
• The presence of surface contaminants
• An under-cured film