Processing properties

Most of the common polymers are processed by a treatment in the molten state, followed by cooling. Dimensionless groups may be derived which control these processing steps. 

Criteria of extrudability, mouldability, spinnability and stretchability as used in practice are described (melt index, spiral length, mouldability index, melt strength, ultimate thread length, etc.). These criteria are based on the dimensionless parameters (numerics) of the processes. 

There are similar temperature and concentration influences on the viscosity of aqueous solutions of many sugars and sugar alcohols. As an example, Fig. 19.2 shows viscosity curves for sucrose as a function of both temperature and concentration. 

The viscosity of glucose syrup depends on its composition. It increases as the proportion of the high molecular weight carbohydrates increases (Fig. 19.3). 

All sugars with free reducing groups are very reactive. In mildly acidic solutions monosaccharides are stable, while disaccharides hydrolyze to yield monosaccharides. Fructose is maximally stable at pH 3.3 glucose at pH 4.0. At lower pH s dehydration reactions prevail, while the Lo-bry de Bruyn-van Ekenstein rearrangement oc- 

Belitz W. Grosch P. Schieberle, Food Chemistry Springer 2009 

Ntiine Relative sweetness Slatting material, applied process 

The use of PES material requires that it be self processed for injection and extrusion molding, etc. The toowledge of the rheological behavior of PES over an industrially relevant range of shear rate and temperature is essential for proper material processability, process design optimization and troubleshooting. 

The power law indices, n, in Table 1 are close to the value (n=0.53) reported by Saini [12]. As can be seen, the values often decrease with a decrease in temperature, and increase with shear rate. In other words, the lower the temperature and the higher the shear rates, the more non-Newtonian the behavior. 

Temperature (°C) Flow index values at shear rates of  

The viscosity of PES decreases with an increase in shear rate. PES as a polymer consists of semi-rigid molecular chains which have a strong affect on rheological behavior. Hence, a decrease in the degree of apparent viscosity of PES is less than that of a flexible-chain polymer, but higher than a rigid-chain polymer, with increase in shear rate. 

Flow tests are run in an actual injection molding machine. Results are usually direct, tangible, and easy to interpret. Typically the flow length mold forms a part in the form of a graduated spirals. The flow length is measured and can be related to flow conditions in an actual production mold. Spiral Flow Length (SFL) data is used especially for comparing various resins for ease of fill [13]. 

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Liquid products must undergo hydrogen processing before joining equivalent crude oil fractions and continuing the normal process property improvement steps. 

CLAIMS UNITERM adds enhanced indexing to the chemical and chemically related patent records general terms to describe processes, properties, end products, etc specific compound terms (over 15,000) and chemical fragment terms to describe generic compounds. 

Dow catalysts have a high capabihty to copolymetize linear a-olefias with ethylene. As a result, when these catalysts are used in solution-type polymerisation reactions, they also copolymerise ethylene with polymer molecules containing vinyl double bonds at their ends. This autocopolymerisation reaction is able to produce LLDPE molecules with long-chain branches that exhibit some beneficial processing properties (1,2,38,39). Distinct from other catalyst systems, Dow catalysts can also copolymerise ethylene with styrene and hindered olefins (40). 

T. J. Carbone, "Production Processes, Properties, and Apphcations for Calcined in High-Purity Aluminas," in L. D. Hart, ed., Jilumina Chemicals Science and Technology Handbook, The American Ceramic Society, Columbus, Ohio, 1990. 

The PEEK resia is gray, crystalline, and has excellent chemical resistance T is ca 185°C, and it melts at 288°C. The unfilled resia has an HPT of 165°C, which can be iacreased to near its melting poiat by incorporating glass filler. The resia is thermally stable, and maintains ductiUty for over one week after being heated to 320°C it can be kept for years at 200°C. Hydrolytic stabiUty is excellent. The resia is flame retardant, has low smoke emission, and can be processed at 340—400°C. Crystallinity is a function of mold temperature and can reach 30—35% at mold temperatures of 160°C. Recycled material can be safely processed. Properties are given ia Table 16. 

Increase in the chain branching in the polychloroprene, reducing the stability in polymer viscosity and deteriorating the processing properties. 

When formulating a silicone adhesive, sealant, or coating, based on hydrosilylation addition cure, one must consider the following properties of the uncured product pot life, dispensing technique, rheology, extrusion rate, cure performance. These characteristics directly affect the processing properties of the polymer base or crosslinker parts. The degree of cure conversion at the temperature of interest is determined by properties such as tack free time, cure profile and cure time. Once... 

Small amounts (usually <10%) of plasticizer could be used in the blending system to improve the processing properties of the material by lowering the melting and glass-transition temperatures. The addition of liquid plasticizer also makes the material soft but at the same time, the strength and toughness of the material decreases. 

When selecting a plasticizer, the overall properties are the major concern. The processing properties of the blending material and cost should also be considered. 

A compatible blend should have good processing properties along with a smooth surface and cross-section. If needed, further tests on mechanical properties should be carried out on testing samples made from 2-mm films produced by compression molding. 

The requirement for consistent, high-quality incoming raw materials comes from the need for the elastomeric compounds to have consistent processing properties. Therefore, it is important to ... 

Thermoplastic elastomers are materials that have the properties of vulcanized rubbers but can be processed by techniques associated with thermoplastics. The commercial importance of TPEs is due to their superior processing properties and economic advantages over conventional rubbers and plastics. TPEs from rubber-plastic blends became important because they combine the superior processability of thermoplastics and the... 

Chemistry of Petrochemical Processes Properties and Uses of Nylons... 

The remaining anhydrides are destroyed by subsequent hydrolysis through the addition of a small amount of water [152,154]. The color of the acid deteriorates during storage and therefore should be processed as quickly as possible, usually by neutralization. The most important is product LAS, which can be found on the market in various forms. The storage and processing properties can be improved by the addition of suitable additives. From such forms (LAS Na content 80-96%) powders can be manufactured by appropriate processes... 

A considerable amount of work has already been successfully carried out in HASETRI with naturally occurring oils as eco-friendly process oils in conventional tire recipes [31,32]. These naturally occurring oils were found to be suitable on the basis of low PCA content. Some of the naturally occurring oils showed better processing properties, polymer-filler interaction, and dispersion properties in NR-based truck tire tread cap compound and hence better mechanical and dynamic mechanical properties. As the presently available low PCA oil in the market in the form of MES TDAE and naphthenic oil are comparatively costly, these natural oils can act as the best alternative processing aids for the elastomer industry, especially in developing and underdeveloped countries. 

Birley AW, Haworth B, Batchelor J (1992) Physics of plastics. Processing, properties and materials engineering. Hanser, Munich... 

Fluorinated ethylene propylene (Teflon) (FEP) is a fully fluori-nated plastic. This polymer was developed to have a combination of unique properties. It combines the desirable properties of PTFE with advantageous melt processing properties. 

J. R. Groza 2002, in Nanostructured Materials - Processing, Properties and Potential Applications, ed. C. C. Koch, William Andrew Publishing, New York, chap. 4. 

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