Smoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires, but may also be used for pest control (fumigation), communication, defensive and offensive capabilities in the military, cooking, or smoking. It is used in rituals where incense, sage, or resin is burned to produce a smell for spiritual purposes. Smoke is sometimes used as a flavoring agent, and preservative for various foodstuffs. Smoke is also a component of internal combustion engine exhaust gas, particularly diesel exhaust.
Polystyrene (PS) is a synthetic aromatic hydrocarbon polymer made from the monomer styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and rather brittle. It is an inexpensive resin per unit weight. It is a rather poor barrier to oxygen and water vapour and has a relatively low melting point. Polystyrene is one of the most widely used plastics, the scale of its production being several million tonnes per year. Polystyrene can be naturally transparent, but can be coloured with colourants. Uses include protective packaging, containers, lids, bottles, trays, tumblers, disposable cutlery and in the making of models.
The flash point of a volatile material is the lowest temperature at which vapours of the material will ignite, when given an ignition source.
The autoignition temperature or kindling point of a substance is the lowest temperature at which it spontaneously ignites in normal atmosphere without an external source of ignition, such as a flame or spark. This temperature is required to supply the activation energy needed for combustion. The temperature at which a chemical ignites decreases as the pressure or oxygen concentration increases. It is usually applied to a combustible fuel mixture.
The term flame retardants subsumes a diverse group of chemicals which are added to manufactured materials, such as plastics and textiles, and surface finishes and coatings. Flame retardants are activated by the presence of an ignition source and are intended to prevent or slow the further development of ignition by a variety of different physical and chemical methods. They may be added as a copolymer during the polymerisation of a polymer, mixed with polymer at an moulding or extrusion process or, in particular for textiles, applied as a topical finish. Mineral flame retardants are typically additive while organohalogen and organophosphorus compounds can be either reactive or additive.
Vinyl siding is plastic exterior siding for houses and small apartment buildings, used for decoration and weatherproofing, imitating wood clapboard, board and batten or shakes, and used instead of other materials such as aluminum or fiber cement siding. It is an engineered product, manufactured primarily from polyvinyl chloride (PVC) resin. In the UK and New Zealand a similar material is known as uPVC weatherboarding.
The melt flow index (MFI) is a measure of the ease of flow of the melt of a thermoplastic polymer. It is defined as the mass of polymer, in grams, flowing in ten minutes through a capillary of a specific diameter and length by a pressure applied via prescribed alternative gravimetric weights for alternative prescribed temperatures. Polymer processors usually correlate the value of MFI with the polymer grade that they have to choose for different processes, and most often this value is not accompanied by the units, because it is taken for granted to be g/10min. Similarly, the test conditions of MFI measurement is normally expressed in kilograms rather than any other units. The method is described in the similar standards ASTM D1238 and ISO 1133.
Low smoke zero halogen or low smoke free of halogen is a material classification typically used for cable jacketing in the wire and cable industry. LSZH cable jacketing is composed of thermoplastic or thermoset compounds that emit limited smoke and no halogen when exposed to high sources of heat.
In physics and engineering, permeation is the penetration of a permeate through a solid. It is directly related to the concentration gradient of the permeate, a material's intrinsic permeability, and the materials' mass diffusivity. Permeation is modeled by equations such as Fick's laws of diffusion, and can be measured using tools such as a minipermeameter.
Biodegradable plastics are plastics that can be decomposed by the action of living organisms, usually bacteria.
A fire test is a means of determining whether fire protection products meet minimum performance criteria as set out in a building code or other applicable legislation. Successful tests in laboratories holding national accreditation for testing and certification result in the issuance of a certification listing. The listing is public domain, whereas the test report itself is proprietary information belonging to the test sponsor.
Flammable materials are those that ignite more easily than other materials, whereas those that are harder to ignite or burn less vigorously are combustible.
A cone calorimeter is a modern device used to study the fire behavior of small samples of various materials in condensed phase. It is widely used in the field of Fire Safety Engineering.
Filler materials are particles added to resin or binders that can improve specific properties, make the product cheaper or a mixture of both. The two largest segments for filler material use is elastomers and plastics. Worldwide, more than 53 million tons of fillers are used every year in different application areas, such as paper, plastics, rubber, paints, coatings, adhesives and sealants. As such, fillers, produced by more than 700 companies, rank among the world's major raw materials and are contained in a variety of goods for daily consumer needs. The top filler materials used are ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), kaolin, talc, and carbon black. Filler materials can affect the tensile strength, toughness, heat resistance, color, clarity etc. A good example of this is the addition of talc to polypropylene. Most of the filler materials used in plastics are mineral or glass based filler materials. There are two main subgroups of filler materials: particulates and fibers. Particulates are small particles of filler which are mixed in the matrix where size and aspect ratio are important. Fibers are small circular strands that can be very long and have very high aspect ratios.
Stabilizers are a class of chemical additives commonly added to polymeric materials, such as plastics, to inhibit or retard their degradation. Polymers can be subject to various degradation processes, including oxidation, UV-damage, thermal degradation, ozonolysis, or combinations thereof like photo-oxidation. These processes all degrade the polymer on a chemical level, leading to chain scission that can adversely affect its mechanical properties such as strength and malleability, as well as its appearance and colour.
Fire-safe polymers are polymers that are resistant to degradation at high temperatures. There is need for fire-resistant polymers in the construction of small, enclosed spaces such as skyscrapers, boats, and airplane cabins. In these tight spaces, ability to escape in the event of a fire is compromised, increasing fire risk. In fact, some studies report that about 20% of victims of airplane crashes are killed not by the crash itself but by ensuing fires. Fire-safe polymers also find application as adhesives in aerospace materials, insulation for electronics, and in military materials such as canvas tenting.
Aluminium diethyl phosphinate is a chemical compound with formula Al(C
4H
10O
2P)3. It decomposes above 300 °C.
Conservation and restoration of objects made from plastics is an activity dedicated to the conservation of objects of historical and personal value made from plastics. When applied to cultural heritage this activity is generally undertaken by a conservator-restorer. Within museum collections there are a variety of artworks and artifacts that are composed of plastic material whether they are synthetic or semi-synthetic; these were created for a range of uses from artistic, to technical, to domestic use. Plastics have become an integral component of life and many plastic objects have become staple icons or objects worth preserving for the future. Although relatively new material for museum collections, plastics having originated in the 19th century, they are deteriorating at an alarming rate, risking the loss not only of the objects themselves, but through their deterioration processes they place objects within their vicinity at risk too. Plastics are made of synthetic, semi-synthetic and organic material, all of which are susceptible to degradation, with their respective off-gassing being harmful to the objects nearby in museum collections.
The four-point bending flexural test provides values for the modulus of elasticity in bending , flexural stress , flexural strain and the flexural stress-strain response of the material. This test is very similar to the three-point bending flexural test. The major difference being that the addition of a fourth bearing brings a much larger portion of the beam to the maximum stress, as opposed to only the material right under the central bearing.
