Crystallinity mechanical properties and

Mati and coworkers [17-21] synthesized a number of poly ethers using a novel nitrate displacement polymerization. The structures of these materials is given below (10-12). This is part of an extensive study that includes evaluation of solubility parameters, biological characteristics, thermal properties, density, crystallinity, mechanical properties, and flame retarding ability. In fact, one of the most common uses for antimony oxides and organoantimony compounds is as flame retardants. The following is a description of some of these results. 

Melt blending studies are currently underway where each composition will be mixed and injection molded into a strip 0.020 inches in thickness. These blends will be analyzed for miscibility, domain size distribution, crystallinity, mechanical properties, and degradability. 

Alternating co-polymerization of olefins with carbon monoxide (CO), typically by using Pd-based catalysts, produces 1,4-polyketones (y-polyketones) that exhibit unique material properties (e.g., high crystallinity, excellent mechanical properties, and high chemical resistance). Whereas Shell suspended their efforts to commercialize these polyketones. 

The key to the successful application of high performance, pourable nitrocellulose plastisols lies in a reasonably priced, high quality source of fine-particle, at least partially colloided, spheroidal nitrocellulose. Here we are speaking of particles much finer than the well-known ball powder, produced by the Olin Mathieson Chemical Co. for small arms for over 30 years (7). Actually, particles on the order of 5-50/x diameter appear to be required to assure a reasonable continuum of uniformly plasticized nitrocellulose binder in a propellant containing 45% or more of combined crystalline oxidizer and powdered metal fuel. Such a continuum of binder is necessary to assure acceptable mechanical properties and reproducible burning characteristics of the finished propellant. Preincorporation of a certain content of the water-insoluble solids within the nitrocellulose microspheres is an effective means of helping to assure this continuum of binder and alleviates the requirements for extremely small ball size. The use of a total of 45% or more of crystalline oxidizer and (generally) metal fuel is essential if the propellant is to be competitive with other modern propellants now in service. 

Heijboer, J. Mechanical properties and molecular structure of organic polymers, in Physics of non-crystalline solids (ed.) Prins, J. A., p. 231, Amsterdam, North-Holland 1965... 

Online separations are often based on spectroscopic identification of polymeric type, but seldom give any indications of polymeric properties (e.g. melt index, crystallinity, mechanical properties) or of the level of low molecular weight compounds. A complicating factor when trying to define properties of recycled plastics has to do with the word contamination . Depending on the context and also the person it may imply as vastly different things as dirt or low molecular weight compounds. 

In addition to the polybenzimidazole blends with imide-siloxanes, it was also demonstrated that other different polyether imide-siloxane-segmented copolymers of variable composition could be used to modify semi-crystalline polyether ketones (PEEK) by presumably an analogous mechanism. The mechanical properties and transition temperatures of those systems have been reported [124,125], and would appear to be additional suitable candidates for the harsh outer space environment (see Table 4 and Fig. 21). 

The engineers must work closely with the chemists, however to ensure that the polymer they are processing has the appropriate composition, degree of crystallinity, and molar mass. Materials scientists may also be consulted because the part being manufactured may not consist of pure polymer It may contain one or more additives or be a composite. The final product must satisfy several important criteria. Its mechanical properties and appearance must remain essentially constant throughout the lifetime of the product. Because... 

The compatibility, mechanical properties, and segmental orientation characteristics of poly-e-caprolactone (PCL) blended with poly (vinyl chloride) (PVC) and nitrocellulose (NC) are described in this study. In PVC blends, the amorphous components were compatible from 0-100% PCL concentration, while in the NC system compatibility teas achieved in the range 50-100% PCL. Above 50% PCL concentration, PCL crystallinity was present in both blend systems. Differential IR dichroism was used to follow the dynamic strain-induced orientation of the constituent chains in the blends. It was found for amorphous compatible blends that the PCL oriented in essentially the same manner as NC and the isotactic segments of PVC. Syndio-tactic PVC segments showed higher orientation functions, implying a microcrystalline PVC phase. 

The various classes of metallic phases that may be encountered in crystalline alloys include substantially pure elements, solid solutions of one element in another and intermetallic compounds. In crystalline form, alloys are subject to the same type of defects as pure metals. Crystalline alloys may consist of a solid solution of one or more elements (solutes) in the major (base) component, or they may contain more than one phase. That is, adjacent grains may have slightly or extremely different compositions and be of identical or disparate crystallographic types. Often, there is one predominant phase, known as the matrix, and other secondary phases, called precipitates. The presence of these kinds of inhomogeneities often results in the alloy having radically different mechanical properties and chemical reactivities from the pure constituent elements. (Noel)5... 

The stereoregularity—i.e., distribution of the stereosequence length in these polymers—has a marked effect on the crystallization rates and the morphology of the crystalline aggregates. These differences, in turn, influence the dynamic mechanical properties and the temperature dependence of the dynamic mechanical properties. In order to interpret any differences in the dynamic mechanical properties of polymers and copolymers of propylene oxide made with different catalysts, it was interesting to study the differences in the stereosequence length in the propylene oxide polymers made with a few representative catalysts. 

Partial replacement of siloxane units with silphenylene groups also increases polymer crystallinity (5, 6), results in a higher viscosity (7), increases the mechanical properties, and improves thermal stability. On the other hand, incorporation of the rigid silphenylene units into the poly siloxane backbones could decrease the low-temperature elasticity of these polymers (8). 

These different contrast mechanisms can all be used to reveal the scale of liquid crystalline polymer microstructures. In specimens that exhibit a mosaic texture, and in those that contain predominantly planar defects, domain size is easily defined in terms of areas that uniformly show extinction between crossed polars. However, if the defects are predominantly linear, as in specimens that exhibit schlieren textures, such simple characterization of microstructural scale is no longer possible. Here it is more convenient to look at the length of disclination line per unit volume, which is equivalent to the number of lines intersecting unit area, and analogous to the dislocation density as defined for crystalline solids. Good contrast is essential in order to obtain an accurate count. Technologically, microstructural scale is of growing interest because of its relevance to processability, mechanical properties and optical transparency. 

Among others, chain flexibility/rigidity, crystallinity, hydrophilicity/hydrophobicity, molecular weight, chemical property, biodegradability, thermal property, mechanical property, and electrochemical property of polymers are considered to affect the performance of membranes most strongly. Moreover, these properties are often mutually interrelated. 

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