Character plasticity

Cornwell DW, Rodary G., Modification of rigid PVC properties through effective use of synthetic calcium carbonates of controlled morphology and surface character, Plastic, Rubbers and Composites, 34, 105-110(2005)... 

When sulphur is melted viscosity changes occur as the temperature is raised. These changes are due to the formation of long-chain polymers (in very pure sulphur, chains containing about 100 (X)0 atoms may be formed). The polymeric nature of molten sulphur can be recognised if molten sulphur is poured in a thin stream into cold water, when a plastic rubbery mass known as plastic sulphur is obtained. This is only slightly soluble in carbon disulphide, but on standing it loses its plasticity and reverts to the soluble rhombic form. If certain substances, for example iodine or oxides of arsenic, are incorporated into the plastic sulphur, the rubbery character can be preserved. 

Up to 0.4 g/L of the iodine stays in solution and the rest precipitates as crystallized iodine, which is removed by flotation (qv). This operation does not require a flotation agent, owing to the hydrophobic character of the crystallized element. From the flotation cell a heavy pulp, which is water-washed and submitted to a second flotation step, is obtained. The washed pulp is introduced into a heat exchanger where it is heated under pressure up to 120°C to melt the iodine that flows into a first reactor for decantation. From there the melt flows into a second reactor for sulfuric acid drying. The refined iodine is either flaked or prilled, and packed in 50- and 25-kg plastic-lined fiber dmms. 

Testing of phthalocyanines includes crystallization (qv), flocculation, and appHcation in paints, plastics (qv), and printing inks (1). The ASTM standard specifications include CuPc in dry powder form for various appHcations (153). The specifications cover color (qv), character or tint, oil absorption, reactions in identification tests, and dispersions and storage stabiUty. Quantitative deterrninations are possible with ceric sulfate (30) or sodium vanadate (154). Identification methods are given (155), including tests for different appHcations. 

Large and small shapes may be sUp cast from both plastic and nonplastic mixes by the usual techniques. Precise shapes, such as glass feeder parts, are made in this way as well as large flux blocks. The process requkes the formulation of a sUp of suitably stable character to be poured into a plaster mold to be dewatered. After it solidifies, the mold is removed and dried further before firing. 

The furnace process involves injecting low end fraction of cmde oil, eg. Bunker Euel C, into a heated chamber. The temperature, shape of the injectors of the oil, rate of injection, and other factors are controlled to produce black fillers of different particle si2e and stmcture. The particle si2e and stmcture control the reinforcing character of the carbon black. There are 30 common grades of carbon black used in the mbber industry. There are numerous specialty grades produced, and several hundred are used in plastic, conductive appHcations, and other uses. 

In the presence of excess fatty acid, different soap crystalline phase compounds can form, commonly referred to as acid—soaps. Acid—soap crystals are composed of stoichiometric amounts of soap and fatty acid and associate in similar bilayer stmctures as pure soap crystals. There are a number of different documented acid—soap crystals. The existence of crystals of the composition 2 acid—1 soap, 1 acid—1 soap, and 1 acid—2 soap has been reported (13). The presence of the acid—soaps can also have a dramatic impact on the physical and performance properties of the finished soap. The presence of acid—soaps increases the plasticity of the soap during processing and decreases product firmness, potentially to the point of stickiness during processing. Furthermore, the presence of the acid—soap changes the character of the lather, decreasing the bubble size and subsequently increasing lather stabiUty and... 

StabiHty (dilution, mechanical, shear, freeze—thaw, heat, bacterial) compatibiHty (plasticizers, thickeners, pigments, extenders, coalescing agents) rheological character... 

Accumulatioa of electrical charges oa textiles, plastics, and other materials of iasulating character causes problems which occur with greater frequency as the relative humidity decreases, particularly duriag wiater months. Heated rooms ia wiater provide an environment ia which static phenomena are frequeafly appareat. 

The mechanical behavior of plastics on time-dependent applied loading can cause different important effects on materials viscoelasticity. Loads applied for short times and at normal rates (Chapter 2) causes material response that is essentially elastic in character. However, under sustained load plastics, particularly TPs, tend to creep, a factor that is included in the design analysis. 

Housman, D. C., Price, M. V. and Redak, R. A. 2002. Architecture of coastal and desert Encelia farinosa (Asteraceae) consequences of plastic and heritable variation in leaf characters. Amer. J. Bot. 89 1303-1310. 

The diametral compressive strength has been used to estimate the tensile strength of certain AB cements (Smith, 1968). In this test, the load is applied diametrically across a cylinder of cement. Theoretical consideration of the test geometry shows that for a perfectly brittle material the failure that occurs is tensile in character. The difficulty in applying this test to AB cements is that they are not sufficiently brittle for this to hold true. In particular, the zinc polycarboxylate and glass-ionomer cements show sufficient plastic character to make the relationship between diametral compressive and tensile strength vary between AB cements of different types like the compressive strength test, this test is valid only as a means of comparison between similar materials (Darvell, 1990). 

Other suggestions on distributed processing reach beyond the capabilities of today s micro reactors, and hence are of more visionary character [5]. These include desktop pharmacies, home-recycle factories, mobile factories, house-water treatment plants, processing cereal crops at the combine, purification of blood in the body, recycling of plastics in the collection vehicle and more [5]. 

The term semisolid infers a unique rheological character. Like solids, such systems retain their shape until acted upon by an outside force, whereupon, unlike solids, they are easily deformed. Thus, a finger drawn through a semisolid mass leaves a track that does not fill up when the action is complete. Rather, the deformation made is for all practical purposes permanent, an outcome physically characterized by saying semisolids deform plastically. Their overall rheological properties allow them to be spread over the skin to form films that cling tenaciously. 

We can divide commodity plastics into two classes excellent and moderate insulators. Polymers that have negligible polar character, typically those containing only carbon-carbon and carbon-hydrogen bonds, fall into the first class. This group includes polyethylene, polypropylene, and polystyrene. Polymers made from polar monomers are typically modest insulators, due to the interaction of their dipoles with electrical fields. We can further divide moderate insulators into those that have dipoles that involve backbone atoms, such as polyvinyl chloride and polyamides, and those with polar bonds remote from the backbone, such as poly(methyl methacrylate) and poly(vinyl acetate). Dipoles involving backbone atoms are less susceptible to alignment with an electrical field than those remote from the backbone. 

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