Competitive Materials

The properties of unmodified PP are compared with other competitive thermoplastics in Table 1. It can be seen from the table that PP offers advantages over most of its competitive materials on the basis of specific modulus (modulus to density ratio), heat deflection temperature (HDT), maximum continuous use temperature or modulus to cost ratio. Environmental and food legislation may further tip the balance in favour of PP. 

PP is most frequently compared with PE but other competitive materials are polystyrene and its derivatives, cellulose acetate (CA), cellulose acetate butyrate (CAB) and PVC. PP is used to replace engineering plastics, such as polyethylene terephthalate (PET), polyamide (PA), polycarbonate (PC) and ABS, etc., in kitchen appliances and domestic appliances. In non-plastics, PP faces competition from glass and metal. 

Major competitive materials for PP and their crude advantages/disadvantages over PP are given in Table 3. This table is for broad comparison only. In many cases, polymers are filled or modified to improve properties or to reduce cost which makes the distinction between the properties of two polymers for a particular application quite blurred. Consequently, choice of a particular material for a given application will require a careful study of the product requirements, material properties and other commercial, environmental and legislative issues. 

LDPE Higher impact resistance Lower brittle temperature Lower strength and stiffness Lower surface hardness Lower heat distortion temperature 

More than 30 years after their invention, polyaryletherketones (PAEK) are present in almost every industry sector. However, world sales are only around 3000 tonnes per year. The high price (around 40 per kilogram) means that alternative materials will be used if possible. In some applications even more expensive polymeric materials such as polybenzimidazole or polyimides must be used to meet performance requirements. 

This chapter briefly reviews the main classes of competitive material and identifies, in general terms, their typical strengths and weaknesses. It should then be clear why PAEK are the material of choice as each of the application segments is reviewed in Chapters 7 and 8. Table 

1 compares some of the basic properties of typical competitive materials. A more extensive review of many of these materials can be found in reference [1]. Here, emphasis is given to the more recent developments. 

Polymer Tensile strength/ MPa Tensile elongation/% Flexural modulus/ GPa Limiting oxygen index (LOI)/% Heat distortion temperature (HDT)/°C Continuous use temperature (CUT)/°C Tm// C Density (g/cm ) 

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Many problems need to be solved before chemurgic materials can be economically used as feedstocks. Among these problems are the recovery, purification, and fractionation of the diverse materials. However, none of these problems are insurmountable. Serious concerns are the supply of the raw material, the relative costs of competitive materials, and competition with other uses for the raw materials. Competition is particularly significant because materials, such as wood, could easily be used in many cases for pulping or even higher value products, such as stmctural timber. Municipal soHd waste offers a substitute raw material with few other uses (33). 

The commercial value of a clay deposit depends on market trends, competitive materials, transportation faciflties, new machinery and processes, and labor and fuel costs. Naturally exposed outcrops, geological area and stmcture maps, aerial photographs, hand and power auger drills, core drills, earth resistivity, and shallow seismic methods are used ia exploration for clays (32). Clays are mined primarily by open-pit operation, including hydraulic extraction however, underground mining is also practiced. 

General Vuleanizate Properties. Table 4 smmnaiizes the properties of CR vulcanizates that ate impoitant to the designers of rubber parts, and compares these properties to those of two competitive materials. The comparison is general and varies depending on compound design (90). The... 

Table 1 Properties of Kevlar and Other Competitive Materials...

Costs of stoneware articles are usually lower than those of competitive materials. The cost per pound is always much lower, but the degree of complexity of the required article and its availability or otherwise in standard stock sizes will, of course, influence the total cost. Owing to the manufacturing methods employed for stoneware, special designs may easily be produced, and hence mould charges may be very low. 

The suitability of proton-conducting materials as separators in a particular fuel-cell application is essentially dependent on its transport properties, durability, and reactivity. Thus far, this review has focused on the transport properties only, but any approach toward new separator materials must consider all relevant aspects, which makes the development of new competitive materials a complex and challenging task. 

One of the major reasons for the intense interest in CNT is their extreme and varied properties. Table 12.7 contains a comparison between SWCNTs and competitive materials and techniques. Another reason is that CNTs are produced from readily available inexpensive materials and are being considered for use as both bulk materials, such as in composites and clothing, and as components in computers, electrical devices, etc. 

Comparison between Selected Properties of Single-Walled CNTs (SWCNTs) and Competitive Materials or Techniques... 

The presence of the admixture at the surface, depending on the forces between the admixture and the surface will impose an additional barrier to the diffusion of hydration products, therefore increasing the length of the dormancy period. Because of the introduction of competitive material for sites, particularly on the C3A phase, the... 

Dental amalgams have been used as dental restorative materials in the United States for the past 160 years and are currently used in approximately 75% of all direct restorations [1]. Of the direct posterior permanent fillings placed in the United States by private practice dentists, 88 % are dental amalgam [2], This material has been considered the preferred material for several reasons. The first is amalgam s history of long term clinical success [3]. The dental amalgam is also easy to place with relatively little technique sensitivity. Dental amalgam is inexpensive to the patient when compared with currently competitive materials... 

Sustainable material management has to pursue both economic and ecological objectives in order to succeed in global competition. Material flows have to be optimised in quantitative and qualitative terms so that the services in question can be rendered with maximum efficiency and minimal emissions. Moreover, business companies are generally aware of the fact that only those companies will survive that continuously improve their performance while enhancing customer orientation and, above all, avoiding excessive resource consumption. 

Use Research., Use research is applied research in the laboratory, field, or plant aimed at determining the potential profitable applications for the new plastic. Such research would include the evaluation and comparison of the new material with potentially competitive material now successfully used. 

Next the identified need and the properties of the engineering plastic have to be meshed. These properties include physical, mechanical, environmental, processing, finishing, and cost characteristics. The way these properties stack up and perform under the use conditions of the part relative to a competitive material really determines if a sale can be closed or the development continues. Making all of this gel takes time, and requires close cooperation between the raw material supplier, end user, and the fabricator. 

It has been estimated that the consumption of rubber in ebonite products increased on an average of about 6% a year until 1951 when different plastics appeared in the market as competitive materials [6]. But because of the superiority of ebonites in acid and chlorine duties, it still maintains its place in the process industries as a material of construction as evidenced by its increased use in anticorrosive lining of chemical process vessels and tanks for the process industries and rolls for steel and textile and paper and pulp industries. 

Mixts of Nitrocyclopentanone with RDX, Hale-ite PETN are more powerful more brisant than corresponding mixts with TNT, but they are also more sensitive. The compd is also a successful plasticizer -for NC in double-base propellants, but a competitive material, DINA, has proved to be more satisfactory... 

The first essential step in color matching is to define the requirements of the color project. A standard form, that is, a color match request (CMR) form, is highly recommended. The CMR form, shown in Figure 5.2, asks the questions needed to define the sphere in which the color match must be accomplished polymer type, standard, competitive material, performance, volume, cost, and so on. Once the CMR is fully filled out, the scope of the match is defined and the process can be started. 

Based on ion-exchange and self-assembly techniques, in this paper we try to synthesize porous silica-montmorillonite heterostructured materials, starting with natural sodium montmorillonite which are ubiquitous so their cost effectiveness will continue to be lower than any synthetic competitive materials. The silica will be orderly assembled within gallery of layers, using the template-directing action. Through the catalytic alkylation reaction of catechol to produce polymerization inhibitor 4-tertbutylcatechol, the catalytic properties of porous silica-montmorillonite heterostructure were evaluated. 

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