Physical characteristics of plastics

Published by the Plastics Design Library, PDLCOM is an exhaustive reference source of how exposure environments influence the physical characteristics of plastics. Data include resistance to thousands of chemicals, weathering and UV exposure (i.e. color change after accelerated weathering or outdoor exposure) sterilization (radiation, ethylene oxide, steam, etc.) thermal air and water aging environmental stress cracking and much more. 

This book focuses on the relationships between the chemical structure and the related physical characteristics of plastics, which determine appropriate material selection, design, and processing of plastic parts. The book also contains an in-depth presentation of the structure-property relationships of a wide range of plastics, including thermoplastics, thermosets, elastomers, and blends. 

The term plastic also refers to a material that has the physical characteristics of plasticity and toughness. See ductility plasticity toughness, plastic, advanced A high-performance material. Also called advanced reinforced plastic or advanced plastic composite. See engineering plastic reinforced plastic, advanced. 

The chemical and physical characteristics of plastics are derived from the four factors of chemical structure, form, arrangement, and size of the polymer. As an example, the chemical structure influences density. Chemical structure refers to the types of atoms and the way they are joined to one another. The form of the molecules, their size and disposition within the material, influences mechanical behavior. It is possible to deliberately vary the crystal state in order to vary hardness or softness, toughness or brittleness, resistance to temperature, and so on. The chemical structure and nature of plastics have a significant relationship both to properties and the ways they can be processed, designed, or otherwise translated into a finished product (Figures 3.8 and 3.9). 

This patented new product is to be used in place of straight antlsKHiy oxide powder or concentrates. This new product, having antlzKmy oxide loadings of 85% or greater, provides dustless operation, improves the physical characteristics of plastics and reduces waste. 

CPA. Copolymer alloy membranes (CPAs) are made by alloying high molecular weight polymeries, plasticizers, special stabilizers, biocides, and antioxidants with poly(vinyl chloride) (PVC). The membrane is typically reinforced with polyester and comes in finished thicknesses of 0.75—1.5 mm and widths of 1.5—1.8 m. The primary installation method is mechanically fastened, but some fully adhered systems are also possible. The CPA membranes can exhibit long-term flexibiHty by alleviating migration of the polymeric plasticizers, and are chemically resistant and compatible with many oils and greases, animal fats, asphalt, and coal-tar pitch. The physical characteristics of a CPA membrane have been described (15). 

The chemical or physical characteristics of solid or liquid additives, such as extenders, white pigments, dispersing agents, plasticizers, or pigment/extender combinations. 

Benzimidazolone pigments, especially those covering the red range of the spectrum, were originally developed and used mostly for plastics. None of them were found to adversely affect the physical characteristics of their host medium. Benzimidazolone pigments do not bloom in plasticized PVC and other polymers. They are usually bleed resistant under typical application conditions. 

Several types of materials are in use in the preparation of containers and closure systems glass, plastics, metals, and combinations of these materials. However, care should be taken in the selection of appropriate material. These materials should not present any physical or chemical reactivity that could modify drug activity, quality, purity, or physical characteristics of the drug and pharmaceutical preparations. Any minor modification in the pharmacopeial specification is acceptable if it does not present a threat to patient s health. 

The physical characteristics of the plastic input influence the carbonization process. In static conditions, the heating rate of small particles is higher than for large particles. In this case, difficulties could occur for the extrapolation from small-scale carbonization data to pilot- and industrial-scale units. The physical and chemical properties of the material are of great importance in order to be able to evaluate the heat transfer from the reactor inside the material. 

Soft lenses are made of hydrophilic hydrogel polymers that contain 36-74% water. Other plastics and copolymers are added to alter the physical characteristics of the lens. The diameter is 10.5-15.5 mm and the thickness at the center 0.03-20 mm. Soft lenses can correct most optical defects, including myopia, hyperopia, and astigmatism. Bifocal lenses are also available. They can be colored with either transparent hnes or opaque patterns to change apparent eye color or to mask malformations of the cornea or iris. They are available for daily, weekly, and twice-weekly disposable nse, 1-3 months frequent replacement, and annual replacement. 

Expansion of the strip after pressure release is influenced by the physical characteristics of the material to be compacted (plasticity, brittleness, particle size and distribution, particle shape, etc.), the roll diameter, the speed of rotation, and the surface configuration of the rollers. With increasing roll diameter and/or decreasing speed the expansion of compacted material is reduced due to better deaeration during densification and a more complete conversion of elastic into permanent, plastic deformation. 

Physical characteristics of polymers are dependant on their molecular weights, molecular shapes and structures. The physical properties of greatest interest to conservation professionals are those used to determine plastics reaction to outside stimuli and environment, their mechanical behaviour and their response to heat. These properties described here under the categories density, electrical, mechanical and thermal. 

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