Processing Characteristics Plasticizers

Function Added to make a compound more flexible, easier to process mainly used with PVC also for cellulosics. 

Materials Monomeric esters of phthalates, adipates, benzoates, mellitates. Polymerizable esters di-phthalate ester. 

Disadvantages Migration strict compliance with food contact regulations. 

New developments Creator efficiency at lower addition levels, easier mixing replacement of potentially hazardous types reduction ofleaching/migration. 

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J. Murphy, "Modifying processing characteristics Plasticizers," in Additives for Plastics Handbook, pp. 169-175. Elsevier Science, Amsterdam, 2nd edition, 2001. 

Additives for Plastics Handbook, Chapter Chapter 14 Modifying Processing Characteristics Plasticizers, J. Murphy, Elsevier, 2001. 

Plasticity Retention Index. The oxidation behavior of natural mbber may affect both the processing characteristics and final vulcanizate performance, and the plasticity retention index (PRI) test can be used to give an indication of both. Natural antioxidants present in natural mbber give some protection and a measure of the efficacy of protection is given by PRI. PRI% = P q j Pq x 100, where Pq is the initial Wallace plasticity and P q is the... 

Petroleum sulfonates have traditionally been produced by both batch and continuous treatment of petroleum oils with oleum. These processes have been covered in several reviews (138,139). Natural petroleum sulfonates are coproducts in the manufacture of a variety of refined oils, most notably white (mineral) oils, lube oils, and process oils (plasticizer oils for mbber compounding). The feedstocks are selected primarily on the basis of the desired characteristics of the refined oils which generally contain 15—30% aromatics. 

Subsequent chapters deal with individual classes of plastics. In each case a review is given of the preparation, structure and properties of the material. In order to prevent the book from becoming too large I have omitted detailed discussion of processing techniques. Instead, with each major class of material an indication is given of the main processing characteristics. The applications of the various materials are considered in the light of the merits and the demerits of the material. 

Recently elaborated methods for predicting volumetric flow rate/pressure characteristics, extrudate structures, and determining high and low limits of optimal processing, can now be used in industrial processing of plastics. 

As there are many different plastics, a number of techniques for defining and quantifying their characteristics exist. As an example molecular weight distribution (MWD) is an indication of the relative proportions of molecules of different weights and lengths. In turn MWD relates to processing characteristics that directly relate to product performances (Chapter 8). 

To maximize control in setting tolerances there is usually a minimum and a maximum limit on thickness, based on the process to be used such as those in Tables 3-6 to 3-9. Each plastic has its own range that depends on its chemical structure, composition (additives, etc.), and melt-processing characteristics. Any dimensions and tolerances are theoretically possible, but they could result in requiring special processing equipment, which usually becomes expensive. There are of course products that require and use special equipment such as polycarbonate compact discs (CDs) to meet extremely tight tolerances. 

As reviewed throughout this book, designing acceptable products requires knowledge of the behavior of the different plastics and their processing characteristics (Chapter 6, MATERIAL VARIABLE and Chapter 8 EQUIPMENT/PROCESSING VARIABLE). 

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. 

Fuel type plasticizers such as phthalates, polyester adipate, or urethane to improve physical and processing characteristics. 

Oxidative transformations of hindered synthetic phenols and a-tocopherol are analogous to the oxidation of various mono- and dihydric phenols of plant origin. Natural phenols present in fruits or green tea leaves are oxidized on contact with air and/or during fermentation (a process characteristic of tea leaves) and are transformed into dark colored quinoid systems, not harmful for human beings. It may be extrapolated that trace amounts of discoloring quinones or quinone methides arising from phenolic antioxidants in plastics are harmless as well. 

When designing and/or fabricating a product a specific plastic is used. A type from a plastic producer and/or requirements for a plastic identifies it. The same named, such as low density polyethylene, from two different companies usually has slightly different properties and processing characteristics. Data throughout this book which identifies a... 

As a construction material, plastics provide practically unlimited benefits to the fabrication of products, but unfortunately, as with other materials, no one specific plastic exhibits all these positive characteristics. The successful application of their strengths and an understanding of their weaknesses (limitations) will allow to produce useful products. With any material (plastic, steel, etc.) products fail not because of its disadvantage(s). They failed because someone did not perform their selection in the proper manner and/or incorrectly processed the plastic. 

Different TS plastics are used such as phenolics, TS polyesters, DAPs, epoxies, ureas, melamines, and silicones, all with their own processing requirements and performance molded properties based on their composiuons. [Note there are TS and TP polyesters (Chapter 2)]. Also used are TPs. TSs are used primarily in CM and TPs in injection molding, extrusion, blow molding, etc. In this review the emphasis is on TSs, which have different processing characteristics to TPs (Chapter 1). 

Mixing carbon with microwave-transparent materials, particularly plastics, and subjecting the mix to microwave radiation, is a very efficient way to heat up such materials, increasing their bulk temperature to a point where pyrolysis occurs. In this chapter the main characteristics of a number of microwave pyrolysis processes, for plastics and other materials, have been introduced, showing that these processes combine the advantages of microwave heating with the commercial and environmental opportunities intrinsic to the pyrolysis of wastes. 

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