Physico-mechanical properties

The Institute has many-year experience of investigations and developments in the field of NDT. These are, mainly, developments which allowed creation of a series of eddy current flaw detectors for various applications. The Institute has traditionally studied the physico-mechanical properties of materials, their stressed-strained state, fracture mechanics and developed on this basis the procedures and instruments which measure the properties and predict the behaviour of materials. Quite important are also developments of technologies and equipment for control of thickness and adhesion of thin protective coatings on various bases, corrosion control of underground pipelines by indirect method, acoustic emission control of hydrogen and corrosion cracking in structural materials, etc. 

Table 7. Physico-Mechanical Properties of Loose Materials.

The synthesis of new polymeric materials having complex properties has recently become of great practical importance to polymer chemistry and technology. The synthesis of new materials can be prepared by either their monomers or modification of used polymers in industry. Today, polystyrene (PS), which is widely used in industrial applications as polyolefins and polyvinylchlorides, is also used for the production of plastic materials, which are used instead of metals in technology. For this reason, it is important to synthesize different PS plastic materials. Among the modification of PS, two methods can be considered, viz. physical and chemical modifications. These methods are extensively used to increase physico-mechanical properties, such as resistance to strike, air, or temperature for the synthesizing of new PS plastic materials. 

New elastic polymeric materials (resistance to higher stroke or air) can be obtained by using physical modification methods, but using this method, two phases (PS and rubber) in the mixture were formed. Small rubber particles spread as a PS layer and, after awhile, the relationship between the layers decreases and rubber particles gather in the upper layer of the materials. This can be the cause of the loss of resistance of the materials. These material disadvantages have stimulated the polymer synthesis to increase the PS resistance to higher physico-mechanical properties, such as higher temperature and stroke for the chemical modification of PS with various functional modifiers. 

The acylation reaction of PS with organic anhydrides, such as maleic and acetic anhydrides, are very important for synthesizing polyfunctional (carbonyl-, carboxyl-, keto-, olefinic) PS. The incorporation of these groups to PS caused an increase of adhesion capability, physico-mechanical properties, elasticity, and photosensitivity [41-46]. 

In general, physico-mechanical properties of polymers depend on the molecular weight. However, the physico-mechanical properties of PSs decreased in the presence of cationic catalysis, but increased in the case of the binding of functional groups to the aromatic ring in spite of the destruction of PS. Therefore, new properties such as adhesion and photosensitive capability increase... 

Figure 7 The physico-mechanical properties of —CO—CH=CH—COOH groups polystyrenes (O, —) resistance to stretch, (cr) (A—) resistance to strike, (a) (A—) relative extention, (e) ( —) hardness (He) ( —-) adhesion, (A).

To introduce some interfacial physico-chemical linkage between EVA and PRP, blends were made by adding different quantities of M AH-PP. Some results are demonstrated in Table 12, The physico-mechanical properties of the PRP-EVA compositions modified with MAH-PP showed that properties are influenced by MAH-PP concentration. Compositions with better impact strength and improved brittleness can be prepared by varying the modifier concentration. Tensile strength and elongation are not significantly influenced by the addition of a modifier. An increase in the modifier con-... 

However, the chief purpose of introduction of fillers into PCM is to make possible the modification of polymers and thereby create materials with a prescribed set of physico-mechanical properties, and, obviously, the properties of filled materials may be controlled by, for example, varying the type of the base polymer (the matrix ) and filler, its particle size distribution and shape. It may not require a large quantity of filler [7]. Thanks to considerable advances in PCM research, their use in a broad range of industries — machine building, construction, aerospace technology, etc. — has become extensive [8 — 11]. 

Table 2. Physico-mechanical properties of polyamide matrices filled with resite particles [141 ]...

Lee [242] studied the dependence of the physico-mechanical properties of Wollastonite-filled polychloroprene rubber on the type of agent used to pre-treat the filler. The composition contained 26.9 part (weight) of the filler per 100 parts (weight) of the rubber (compositions CR-1100, CR-174, CR-151). The finishing agents were y-aminopropyl triethoxysilane (CR-1100 and CR-174) and vinyl triethoxysilane (CR-151). The mechanical properties of the compositions are listed in Table 7 below. The author proposed an empirical equation to relate the modulus with the equilibrium work of adhesion in the following form ... 

Table 8. Heats of interaction and physico-mechanical properties of PVC-based filled plasticized compositions [100]...

Physico-Mechanical Properties of Composites with Polymerization-Modified Fillers (PMF)... 

The introduction of large gas phase volumes into the polymer alters the physical characteristics of the material volume weight, permeability to fluids and gases, and physico-mechanical properties. Moreover, the properties of the polymer matrix itself are changed (owing to orientation effects, supermolecular structure of the polymer in the walls, ribs and tension bars of cells), which drives up the value of specific strength on impact, and results in anisotropy of elasticity. 

The fibres spun from copolymers of AN with 4 formed by the wet process from DMF solutions have satisfactory physico-mechanical properties. 

Different characteristics of solvents seriously affect the sol-gel reaction in solution. This in turn influences the physico-mechanical properties of the resultant rubber-silica hybrid composites. Bandyopadhyay et al. [34,35] have carried out extensive research on stmcture-property correlation in sol-gel-derived rubber-sihca hybrid nanocomposites in different solvents with both chemically interactive (ENR) and noninteractive (ACM) mbber matrices. Figure 3.12 demonstrates the morphology of representative ACM-sihca and ENR-sihca hybrid composites prepared from various solvents. In all the instances, the concentration of TEOS (45 wt%), TEOS/H2O mole ratio (1 2), pH (1.5), and the gelling temperature (ambient condition) were kept unchanged. 

Fluoroelastomers Novikova et al. [32] reported unproved physico-mechanical properties of fluoro mbbers by reinforcement with chopped polyamide fibers. Other fiber reinforcements are covered by Grinblat et al. [33]. Watson and Francis [34] described the use of aramid (Kevlar) as short fiber reinforcement for vulcanized fluoroelastomer along with polychloroprene mbber and a co-polyester TPE in terms of improvement in the wear properties of the composites. Rubber diaphragms, made up of fluorosilicone mbbers, can be reinforced using aramid fiber in order to impart better mechanical properties to the composite, though surface modification of the fiber is needed to improve the adhesion between fluorosUicone mbber and the fiber [35]. Bhattacharya et al. [36] studied the crack growth resistance of fluoroelastomer vulcanizates filled with Kevlar fiber. 

Furthermore, our results on the characterization of the physico-mechanical properties of tyrosine-derived poly(iminocarbonates) provide preliminary evidence for the soundness of the underlying experimental rationale The incorporation of tyrosine into the backbone of poly(iminocarbonates) did indeed result in the formation of mechanically strong yet apparently tissue-compatible polymers. 

Investigation of various donor-acceptor interactions in a polymer, where all the chemical reactions have been completed, is also of great interest because these interactions considerably affect its physico-mechanical properties. 

The above mechanism of the diffusion-controlled curing provides a good explanation of the established relation between various physico-mechanical properties of the... 

Table 1. Dependence of the kinetic parameters of the reaction, the structural parameters of the network and the physico-mechanical properties of polyurethane elastomers on the molar fraction of OH groups in the monofunctional reagent21...

Graftcopolymerization onto silicone rubber is rather difficult to achieve and is often accompanied by unwanted changes in physico-mechanical properties of the polymer caused by initiating agents. To overcome the problem, silica was introduced into the rubber matrix as an active filler capable of binding cationic compounds such a cationic compound being y-aminopropyltriethoxysilane. Schematically the pathway for heparinization of the latter may be presented as follows ... 

This examination includes numerous technical tests and investigations made with the object of determining the physico mechanical properties of the wares. The results obtained, together with those of the microscopic and chemical examinations, indicate if the material possesses the necessary characters for the required purpose and also allow of its value being established. This examination is carried out on a sample so chosen that it represents as far as possible the whole parcel. The tests made are numerous and only a few of the more important are given shortly here further details may be found in special books on the subject.1... 

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