Plastics combined with other materials

Film and sheet are defined as flat unsupported sections of a plastic resia whose thickness is very thin ia relation to its width and length. Films are generally regarded as being 0.25 mm or less, whereas sheet may range from this thickness to several centimeters thick. Film and sheet may be used alone ia their unsupported state or may be combined through lamination, coextmsion, or coating. They may also be used in combination with other materials such as paper, foil, or fabrics. 

A variety of cellular plastics exists for use as thermal iasulation as basic materials and products, or as thermal iasulation systems ia combination with other materials (see Foamed plastics). Polystyrenes, polyisocyanurates (which include polyurethanes), and phenoHcs are most commonly available for general use, however, there is increasing use of other types including polyethylenes, polyimides, melamines, and poly(vinyl chlorides) for specific appHcations. 

Costs of ceUular plastic insulations are stiU higher than those of fibrous and other mass insulation types, but these can often be justified based on overall advantages of combined stmctural, thermal, and permeance properties. It is difficult to provide a single cost for each material type since there are many different forms of a material-based product avaUable and differing forms of manufacture and appHcation, often in combination with other materials. In the United States, EPS board costs on the order of 0.12 to 0.18 XEPS, 0.25 to 0.30 and PU, 0.30 to 0.35, per board foot ( 0.30/board ft fx 127/m ). 

From a practical review, perhaps it can be stated that buildings and construction materials are exposed to the most severe environments on earth, particularity when the long time factor is included. The environments include such conditions as temperature, ultraviolet, wind, snow, corrosion, hail, wear and tear, etc. Basically the following inherent potentials continue to be realized in different plastics ease of maintenance, light weight, flexibility of component design, combine with other materials, corrosion/abrasion/weather resistance, variety of colors and decorative appearance, multiplicity of form, ease of fabrication by mass production techniques, and total cost advantages (combinations of base materials, manufacture and installation). 

With the application of plastics in combination with other materials, the coefficient of expansion plays an important role in making design allowances for expansions (also contractions) of various materials at different temperatures so that satisfactory functions of products are ensured. 

Plastics can also be combined with other materials such as aluminum, steel, and wood to provide specific properties. Examples include PVC/wood window frames and plastic/ aluminum-foil packaging material. All combinations require that certain aspects of compatibility such as processing temperature and linear coefficient of thermal expansion or contraction exist. 

Arcus gasification combuster is described and the principles upon which it works are explained. This combuster combines solid fuel gasification with the burning of the lean gases produced on a small capacity scale. The types of solid fuels which can be used are listed and these include segregated municipal waste and industrial waste such as rigid PU foam and plastics mixed with other materials. Uses of the gas produced are included. 

Recent discoveries in the fields of plastics and synthetic fiber production have resulted in materials with excellent armoring properties. These new products are being used not only as individual armor pieces, but also in combination with other materials.These composite applications allow the designer to choose the type of armor most suited to the design criteria outlined in Section II. 

Plastics are used in virtually every pharmaceutical application (oral, topical, ophlthalmic, parenteral applications), either as a single material or in combination with other materials, as coatings or laminations. 

Polytetrafluoroethylene has a somewhat higher coefficient of expansion than other plastics. This differential expansion can result in leaking of joints when PTFE is combined with other materials. Addition of fillers such as glass, fiber, graphite, bronze, and molybdenum disulfide alters the coefficient of expansion of polytetrafluoroethylene compounds (Table 3.36). A compound containing 25% filler has a coefficient of expansion about half that of the unmodified resin. 

With the exception of glass and mineral fiber products, and, like rubbers and plastics, textiles are largely hydrocarbon polymers and as such have a strong tendency to ignite and burn from a small flame. Textiles are essentially sheets of woven, knitted, or sometimes randomly orientated fibers and may be directly used on their own or in combination with other materials, e.g., coated fabrics, or as reinforcement, e.g., in rubber hoses. Other examples of textile products are upholstered furniture and protective clothing. 

EPI adhesives have very good adhesion properties to the wood surface and thus can glue different wood species very well. Since this adhesive type also has very good adhesion to materials like metals, plastics and foams, it is very well suited for gluing composite materials where wood is combined with other materials [2,4, 5]. The excellent adhesion of EPI adhesives to metals has to be taken into account in the production process since the glued pieces may adhere to the press plates if no surface treatment of the press plates is used. Release agents are available and are in use. 

The use of polymers seems limitless in its variety the technology associated with these uses rich in its sophistication. One of the main reasons for this is that polymers are virtually never used alone, but always in combination with other materials. These added materials may be stabilizers, plasticizers, reinforcing fibers, pigments or other polymers, formulated into multi-component systems with properties well suited for specified applications. Obviously, in multi-phase polymer systems, interfaces and interphases must exist. It seems obvious intuitively that the nature of these interfaces and interphases will affect the performance of the system as a whole. Inherent in that statement is the link between component interactions on the one hand, and the rheological, physico-chemical and mechanical properties of the system, on the other. 

PET in fibers and bottles and polycarbonates in compact discs represent large-volume markets. As with most polymer families, there is a wide diversity of applications, many of which involve combinations with other materials. Aliphatic polyesters have been used as lubricants and vinyl plasticizers. Hydrolytic stability is a factor to be considered in many applications. As a rule, aryl acids and branched-chain diols resist hydrolysis. Fibers and films of terephthalic acid esters and polycarbonates are not particularly sensitive to moisture. Alkyd resins are so highly cross-linked in the final coating that water is not a major problem, although alkaline solutions of soaps and detergents can cause film failure. It is in the urethane foams that hydrolytic stability... 

Hybrids combine plastics or composites with other materials such as metal, wood, etc. Plastics filled with talc or other powders are not taken into account in this chapter. 

The polymeric materials usually used to manufacture rigid closures are practically the same as those seen under plastic containers (Section 6.1.3.2). The same impurities are therefore to be expected in these packaging components. On the other hand, though made of polymeric materials, elastomeric closures present a different structure. In the manufacture of rubber, elastomer, the chief component, is combined with other chemicals to produce a material with specific properties that meet target needs, such as its above-mentioned ability to reseal on repeated use. Table 28 lists the common elastomers used in the pharmaceutical industry and their monomeric structures. 

Techniques and plants for polymerization have become more precise and specific but there is a possibility still that similar grades of the same material made in different units may differ in practice (in features such as the distribution of molecular weights, and colour). It will be appreciated too that many polymers and copolymers are used in combination with other substances— stabilizers, fillers, and miscellaneous additives—all of which (and especially those occurring naturally, like China clay and some types of plasticizer) may themselves differ appreciably from batch to batch. 

In 2004, Office Media (Tokyo) developed a new PLA film exhibiting vastly improved functionality as a packaging material. Through combination with other biodegradable plastics, the film s transparency, flexibility, heat resistance and impact resistance, have been balanced in multiple dimensions, and through adopting two-layer and three-layer structures, gas barrier properties have also been improved. Technology to eliminate the characteristic odour of PLA developed independently by Office Media, have also been applied. 

Customer preferences for recycled products have encouraged a more efficient use of wood and natural fibers. One potential approach to preserve wood and use natural fibers is the development of commodity-engineered composites that blend wood and natural fibers with other materials, such as plastic. The idea of combining wood and plastic is to produce a product with performance characteristics that combine the positive attributes of both materials. Wood and other natural fibers have been used as fillers and/or reinforcement to improve the mechanical properties of a variety of products. The combination of wood and plastic creates the ability to develop diverse products using many different manufacturing processes. 

It is possible to make completely new types of composites by combining different resources. It is possible to combine, blend, or alloy leaf, bast and stick fiber with other materials such as glass, metals, plastics, and synthetics to produce new classes of materials. The objective is to combine two or more materials in such a way that a synergism between the components results in a new material that is much better than the individual components. 

The dimensional stability of plastic structural components - especially when integrated with other parts to make up components or a system, and in particular in combination with different materials (steel, aluminum, magnesium, ceramic, fiber composites) - is often a factor of central importance in technical applications (Fig. 75) [16]. 

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