Durability reprocessing

This is an extremely important area. Commercial polymers are very rarely prepared or used without additives and they often contain a combination of additives. These improve processability of the polymer, its durability, service life under adverse conditions (e.g., temperature, UV light and various chemical environments), strength (e.g., using reinforcing fillers), appearance (colorants), etc. A recent use of additives is to facilitate reprocessing or recycling or, alternatively, to promote decomposition (which is often difficult because the stability is inherent in the polymer s chemical structure). (The analysis of additives in polymers is the subject of Chapter 14.)... 

Profile material has been successfully subjected to repeated extrusion to investigate the effect of loss of properties and durability when PVC waste is reprocessed. Colour deterioration was the main issue (indicating a need for a virgin cap material to retain colour, if necessary) (211). Fence posts based on a core of recycled PVC, enclosed in a virgin cap skin, have been developed. At present, this depends on post industrial waste, such as off-cuts and off specification profile materials as the source (99). Arecycling project, for vinyl sidings in the USA, has also been conducted (397) (www.vinylinfo.org). 

Is a semi-durable solvent phase water repellent material designed for use in a complete solvent system. This product is frequently useful in drycleaning establishments for the reprocessing of outerwear garments to produce water repellency. 

During the past ten years, there has been considerable research devoted to the development of crystalline waste forms for actinide immobilization [7,8,24,27, 28,39,40,67,68,41-43,69]. Many of the phases are based on studies of minerals that contain Th and U, such as pyrochlore [16-18], zirconolite [70,71], zircon [1,72], monazite [73], britholite [74]. Based on their degrees of alteration, most of the minerals are considered to have an acceptable chemical durability. In addition, closely related mineral structures, such as murataite and garnet, which do not contain U or Th have been synthesized with actinides [29,75,76]. Multiphase ceramics. Ceramic matrices were initially designed for the immobilization of non-partitioned HLW from SNF reprocessing and considered... 

Although the work on TPD is relatively recent, there is already a substantial amount of data on its chemical durability, and leach rates are comparable to those of other phosphate waste forms. One can anticipate important advances in the use of TPD or mixed phase assemblages of TPD-monazite (Clavier et al., in press) in reprocessing spent nuclear fuel, processing HEW, and developing new nuclear waste forms for special applications. 

High-level radioactive waste (HLW) will be converted from an alkaline slurry to a durable borosilicate glass in the Defense Waste Processing Facility (DWPF) at the Savannah River Plant (SRP) in South Carolina [17]. This waste is the residue from thirty years of reprocessing of irradiated nuclear fuels for national defense purposes and is currently stored in large carbon-steel tanks. 

I. Jakubowicz, J. Enebro, Effects of reprocessing of oxobiodegradable and non-degradable polyethylene on the durability of recycled materials. Polym. Degrad. Stab. 97, 316 (2012)... 

It was found that the use of 30% liquid-crystal copolyester of n-oxy-benzoic acid/polyethyleneterephthalate makes polymethylmethacrylate 30% more durable and increases the elasticity modulus on 110%, with the reprocessibility being the same. 

Linear polysulfones based on bisphenylolpropane and containing iso-propylidene groups in the chain are easily reprocessible into the articles and have high hydrolysis stability. The presence of simple ester links in the polymeric chains makes them more flexible and durable. The main effect on properties of such polysulfones is produced by sulfonic bond which makes the polymer more stable to oxidation and more resistant to heat. Above properties of polysulfones along with the low cost of bisphenylolpropane change them into almost ideal polymers for constmctional plastics. Polysulfones of higher heat-resistance can be obtained on the basis of some other bisphenols. 

The mechanical recycling is recommended by authorities at a level of 10 to 15%. At the same time, the first R D efforts have been committed to recovery of single pol5Tner species, with an option of their reprocessing either to the original application or to less demanding use or preferably into durable items (for example bottles to pipes). 

In considering life cycle assessments, it is useful to divide products into three major categories as illustrated in Fignre 14.6. Consumable products, such as gasoline bnrned in an antomobile engine, are used up or dispersed to the environment with no possibility of recovery. Recyclable commodities are potentially reclaimed, reprocessed, and reused engine oil is such a material. Service products (sometimes called durable products) are devices that can be nsed multiple times and have a long lifetime. An automobile is a service product. 

The amount of plastics recycled in 1998 was 260,000 tons from durable goods, and 950,000 tons from containers and packaging, for a total of 1.2 million tons. Plastics News reported sales of North American plastics recyclers and brokers totaled 1.74 billion in 2000, with 29 percent of that post-consumer plastics and the remainder post-industrial and brokered plastics. The total amount of plastics reprocessed was 5.54 biUion pounds. ... 

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