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A-STAGE. An early stage in the reaction of certain thermosetting resins, in which the material is still soluble in certain liquids and fusible. Sometimes referred to as resol. (See C-STAGE.)
ABS. (See ACRYLONITRILE BUTADIENE STYRENE.)
ABSORPTION. (1) The penetration into the mass of one substance by another (2) The process whereby energy is dissipated within a specimen placed in a field of radiation energy. Since processes other than absorption occur, e.g., scattering, in which only a fraction of the energy removed from a beam is retained in the specimen. The total amount of energy removed from a well-collimated beam will be greater than the amount actually dissipated within the sample.
ACETAL RESIN. The molecular structure of this polymer is that of a linear acetal, consisting of unbranched poly-oxymethylene chains.
ACID-ACCEPTOR. A compound which acts as a stabilizer by chemically combining with acid which may be initially present in minute quantities in a plastic, or which may be formed by the decomposition of the resin.
ACRYLIC PLASTICS. Plastics based on resins made by the polymerization of acrylic monomers, such as ethyl acrylate and methyl methacrylate.
ACRYLIC RESIN. A synthetic resin prepared from acrylic acid or from a derivative of acrylic acid.
ACRYLONITRILE BUTADIENE STYRENE (ABS). Acrylonitrile and styrene liquids and butadiene gas are polymerized in a variety of ratios to produce the family of ABS resins.
ACTIVATION. The process of inducing radioactivity in a specimen by bombardment with neutrons and other types of radiation.
ADDITIVES. Products that are combined with resins and polymers as extenders or modifiers to alter the properties of the base polymer.
ADHEREND. A body which is held to another body by an adhesive.
ADHESION. The state in which two surfaces are held together by interfacial forces which may consist of valence forces or interlocking action or both. (See ADHESION, MECHANICAL; ADHESION, SPECIFIC.)
ADHESION, MECHANICAL. Adhesion between surfaces in which the adhesive holds the parts together by interlocking action. (See ADHESION, SPECIFIC.)
ADHESION, SPECIFIC. Adhesion between surfaces which are held together by valence forces of the same type as those which give rise to cohesion. (See ADHESION, MECHANICAL.)
ADHESIVE. A substance capable of holding materials together by surface attachment. Adhesive is the general term and includes among others cement, glue, mucilage, and paste. All of these terms are loosely used interchangeably. Various descriptive adjectives are applied to the term adhesive to indicate certain characteristics, as follows: physical form, e.g. liquid adhesive; tape adhesive chemical type e.g. silicate adhesive; resin adhesive materials bonded, e.g., paper adhesive; metal-plastic adhesive; can-label adhesive conditions for use, e.g. hot-setting adhesive.
ADHESIVE, ASSEMBLY. An adhesive which can be used in bonding parts together, such as in the manufacture of a boat, airplane, furniture, and the like. The term assembly adhesive is commonly used in the wood industry to distinguish such adhesives (formerly called joint glues) from those used in making plywood (sometimes called veneer glues). It is applied to adhesives used in fabricating finished structures of goods, or subassemblies thereof as differentiated from adhesives used in the production of sheet materials for sale as such, for example, plywood or laminates.
ADSORPTION. A concentration of a substance at a surface or interface of another substance.
AGING. (1) The effect of exposure of plastics to an environment for an interval of time. (2) The process of exposing plastics to an environment for an interval of time. Aging, according to the first definition, may be very great or not, depending on the environmental conditions, such as radiating, moisture, temperature, surrounding gases, etc., and the period of exposure.
AIR-ASSIST FORMING. A method of thermoforming in which air flow or air pressure is used to partially preform the plastics sheet immediately prior to the final pulldown onto the mold using vacuum.
AIR-SLIP FORMING. A variation of snap-back forming in which the male mold is enclosed in a box in such a manner that when the mold moves forward toward the hot plastics, air is trapped between the mold and the plastics sheet. As the mold advances, the plastic is kept away from it by the air cushion until the full travel is attained, at which point a vacuum is applied, removing the air cushion and forming the part against the plug.
AIR VENT. Small outlet usually a groove, to prevent entrapment of gases.
ALKYD PLASTICS. Plastics based on resins composed principally of saturated polymeric esters, in which the recurring ester groups are an integral part of the main polymer chain, and in which ester groups occur in any cross-links that may be present between chains. ( POLYESTER PLASTICS.)
ALL-VENEER CONSTRUCTION. Plywood without lumber cores, more frequently multiple for strength requirements, often 7-ply or 9-ply, to equal the thickness of conventional member-core plywood. The maximum thickness of any single sheet of veneer seldom exceeds 1/4".
ALLOY. Composite material produced by blending polymers or copolymers with other polymers or elastomers under controlled conditions.
ALLYL DIGLYCOL CARBONATE (ADC). A crystal clear thermosetting plastic with outstanding scratch resistance; used for goggles, etc.
ALLYL PLASTICS. Plastics based on resins made by additional polymerization of monomers containing ally groups, such as diallyl phthalate.
AMBIENT TEMPERATURE. Temperature of the medium surrounding an object.
AMINO PLASTICS. Plastics based on resins made by the condensation of amines such as urea and melamine, with aldehydes.
AMORPHOUS POLYMERS. Polymers that have randomly oriented molecular structure with no definite order or regularity.
ANCHORAGE. Part of the insert that is molded inside of the plastic and held fast by the shrinkage of the plastic.
ANILINE FORMALDEHYDE RESINS. Member of the aminoplastics family made by the condensation of formaldehyde and aniline in an acid solution. These resins are thermoplastic and have high dielectric strength.
ANNEAL (1) To heat a molded plastic article to a predetermined temperature and slowly cool it to relieve stresses. (2) To heat steel to a predetermined temperature above the critical range and slowly cool it, to relieve stresses and reduce hardness.
ANTIOXIDANT. A substance that prevents or slows down oxidation of plastics material that is exposed to air.
ANTISTATIC AGENTS. Materials and treatments used during or after the molding process to minimize static electricity in plastics materials.
ASSEMBLY. The collection of and placing together in proper order of the layers of veneer, lumber, and/or other materials with the adhesive ready to be pressed and bonded into a single unit.
ASSEMBLY TIME. In adhesives, refers to the elapsed time after the adhesive is spread and until the pressure becomes effective.
ATACTIC. A random arrangement of the unsymmetrical group with respect to the carbon-carbon backbone plane.
AUTOCLAVE. A closed vessel capable of withstanding high temperatures and pressures. Useful for conducting chemical reactions.
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