Engineering plastics compounding

A three-year joint European project, RECAM, recommends that it should be possible to colleet more than 50% of carpet waste in Western Europe. High-grade materials such as PA and PP could be recovered for the manufacture of engineering plastics compounds and more than 8 million Gigajoules of energy could be reeovered from the remainder. At the heart of the proj ect are ehemieal recycling processes developed by both DSM and Enichem. 

Plastics carboys Plastics compounding Plastics, engineering Plastic sheet Plastics processing Plastics testing Plastic tapes Plastic working Plastiform Plastisols... 

Plastics. In the plastics industry, the term filler refers to particulate materials that are added to plastic resins in relatively large, ie, over 5%, volume loadings. Except in certain specialty or engineering plastics appHcations, plastics compounders tend to formulate with the objective of optimizing properties at minimum cost rather than maximizing properties at optimum cost. Table 2 fists typical plastic fillers and their uses. 

Derivatives of CPD have also been incorporated into these resins. CPD and 2-butene-l,4-diol have been condensed in ethanol and catalyticaHy hydrogenated in situ to give 2,3-bis(hydroxymethyl)bicyclo[2.2.1]heptane (51). This latter compound is used as a chain extender in polyesters for engineering plastics (52). 

Commonly accepted practice restricts the term to plastics that serve engineering purposes and can be processed and reprocessed by injection and extmsion methods. This excludes the so-called specialty plastics, eg, fluorocarbon polymers and infusible film products such as Kapton and Updex polyimide film, and thermosets including phenoHcs, epoxies, urea—formaldehydes, and sdicones, some of which have been termed engineering plastics by other authors (4) (see Elastol rs, synthetic-fluorocarbon elastol rs Eluorine compounds, organic-tdtrafluoroethylenecopolyt rs with ethylene Phenolic resins Epoxy resins Amino resins and plastics). 

The UL flammability ratings describe the relative ease of ignition and combustibiUty of plastics. Tests include the measurement of flame propagation, time to self-extinguish, melt and drip with and without flame, and oxygen indexes. Some engineering plastics, eg, polyetherimides, are, as ranked by this test, inherently nonflammable. Others can be made nonflammable by compounding with flame retardants (ERs) such as bromine... 

Aroma.tic-AUpha.tic Polyester Resins. Unlike most other classes of engineering plastics, which are made by only a few manufacturers, aromatic-aHphatic polyester resins are produced and compounded by several dozen firms (66). The aHphatic polyester resin marketplace is characterized by wide product differentiation and competition. Some firms make only a few hundred tons per year and presumably retain profitabiHty because of the avadabiHty of low cost monomer and the simplicity of the processes employed. Low investment and low manufacturing costs are possible even for smaH-volume operations. 

In recent years there has been some concern in the thermosetting material industry that usage of these materials is on the decline. Certainly the total market for thermoset compounds has decreased in Western Europe. This has happened for a number of reasons. One is the image that thermosets tend to have as old-fashioned materials with outdated, slow production methods. Other reasons include the arrival of high temperature engineering plastics... 

In addition to the broad categories of TPs and TSs, TPs can be further classified in terms of their structure, as either crystalline, amorphous, or liquid crystalline. Other classes (terms) include elastomers, copolymers, compounds, commodity resins, engineering plastics, or neat plastics. Additives, fillers, and reinforcements are other classifications that relate directly to plastics properties and performance. 

As aromatic compounds have been exhausted as building blocks for life science products, A-heterocyclic structures prevail nowadays. They are found in many natural products, such as chlorophyll hemoglobin and the vitamins biotin (H), folic acid, niacin (PP), pyridoxine HCl (Be), riboflavine (B2), and thiamine (Bi). In life sciences 9 of the top 10 proprietary drugs and 5 of the top 10 agrochemicals contain A-heterocycIic moieties (see Tables 11.4 and 11.7). Even modern pigments, such as diphenylpyrazolopyrazoles, quinacri-dones, and engineering plastics, such as polybenzimidazoles, polyimides, and triazine resins, exhibit an A-heterocydic structure. 

The UL temperature indexes for a variety of engineering plastics are in Table 4. Glass-filled PPS compounds exhibit a high UL temperature index, which indicates excellent retention of properties for long-term exposure to high temperature. Other fillers, eg, mineral (talc), may also be used. ... 

Organic compounds having labile hydrogens, such as phenols [41,42], phenylene-diamines [43], and acetylenes [44], can be oxidatively coupled in the presence of specific metal complexes to form polymeric compounds. The oxidative polymerization of 2,6-disubstituted phenols with a copper-amine complex produces poly(2,6-disubstituted phenylene ether) [45-51], Poly(2,6-dimethylphenylene ether) and poly(2,6-diphenylphenylene ether) are commercially produced from 2,6-dimethyl phenol and 2,6-diphenylphenol, respectively (Figure 5). These polymers exhibit excellent performance as engineering plastics. 

Typical applications for products and processes with high and low torque requirement are shown in Fig. 14.9. Typical uses of high torques are reinforcing and alloying of engineering plastics and compounding and pelletizing of polyolefin powders into polyolefin pellets, or direct extrusion of films. Low torques are used for products that are shear-sensitive or difficult to feed, such as those often found in the chemical/food/pharmaceutical industries. 

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