In products properties

Solvent recovery is fast and complete, with minimal residue in product. Properties of GO2 as a solvent ... 

At this point, the final specifications for the one or two chosen product(s) after selection process should be identified. This can be done using a three-step procedure. First, we define the product micro and macrostructure. Second, we rank the product s most important attributes, an effort that forces a review of how the product will be used. Third, we review any chemical triggers, that is, chemical stimuli which cause major changes in product properties. Finally, we turn to the manufacture itself, which relies on technical know-how of thermodynamics, chemical reaction kinetics, transport phenomena, and unit operations. Some of these ideas are illustrated in the following example. Except for a schematic of the manufacturing process, the many details related to the manufacturing plant are omitted in this discussion. 

The chemical systems for RIM all have one characteristic in common they require a RIM machine to convert liquid raw materials into quality plastic products. Assuming a properly formulated chemical system, the quality of the end product results from the ability to measure, control (Chapter 3), and adjust temperature, ratio, pressure, and other essential process parameters of the RIM dispensing machine. Such exacting control leads to a reduction in start-up time, minimal rejects and touch-up work, reproducible product quality, and the ability to pinpoint changes in product properties. 

Continuous processes will generally not be used for acrylic surface coating latexes, adhesives, and other low tonnage products. Scmibatch processes are frequently used in which not all the ingredients are added initially. Continuous systems are favored for large-volume polymers like SBR in order to increase the reactor output and reduce fluctuations in product properties. Such continuous reactor trains usually consist of a series of batch reactors each connected with bottom inlets and top outlets and operated with continuous overflow. 

In a single CSTR, monomer and other ingredients of the polymerization recipe are continually fed into the vessel while polymer and the rest of the reaction mixture are removed. The effluent can, of course, serve as the feed to the next CSTR in a series operation. Problems with heat removal are alleviated to some extent because of the beneficial effects of cold monomer feed and the removal of reaction heat with the effluent. CSTR reactors are economically attractive for large-scale production with relatively infrequent changes in product properties. 

Below a certain degree of agitation (i.e., 200 rpm) product quality deteriorated drastically, but increased agitation beyond the minimum brought only marginal changes in product properties. 

In daily practice, researchers and product developers aim to connect the results of analytical research - in this case thermal analysis - to improvements in product properties. To be effective, researchers need the capability to change the... 

There are two commercial installations of Condebelt dryers on board machines. According to recent reports [75,76], the minor operational issues have been resolved with modified design and expected improvements in product properties are realized. 

InjGCtion Molding. This market, which includes fids, buckets, toys, freezer containers, has seen significant penetration by LLDPE. LLDPE offers advantages in product properties such that higher melt index products can be used without sacrificing product performance. The use of the higher melt indices allows the fabricator to increase production speed and reduce costs. The markets where LDPE... 

Figure 7.31 Improvement in product properties by a direct molding system. Impact kgfcm/cm Flex. Modulus kgf/cm2 DI Direct feeding in injection molding machine Comp. Conventional compounding system D.M. Direct compounding and molding system...

Irreversible behavior. It is often impossible to reverse the effects of history-dependent evolution in product properties such as molecular weight distribution in a polymer or crystal size distribution in a pharmaceutical product. In the semiconductor industry, once a semiconductor wafer is made, it is difficult to modify its electrical properties by further processing or rework. 

Each combination of reactor system, polymerization conditions and initiators or catalysts produces a different molecular structure. In addition, some variation in catalyst activity and operating conditions is inevitable in an industrial setting, so that some variability in product properties from one day to the next is a normal aspect of commercial polymer production. 

The results of the two-reactor bench-scale unit are discussed first in this section to analyze the effect of reaction conditions on impurities removal and changes in product properties. The results of the one-reactor bench-scale unit are reported later to develop the kinetics of the different noncatalytic reactions. 

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