Morphology crystallinity

Compatibility and various other properties such as morphology, crystalline behavior, structure, mechanical properties of natural rubber-polyethylene blends were investigated by Qin et al. [39]. Polyethylene-b-polyiso-prene acts as a successful compatibilizer here. Mechanical properties of the blends were improved upon the addition of the block copolymer (Table 12). The copolymer locates at the interface, and, thus, reduces the interfacial tension that is reflected in the mechanical properties. As the amount of graft copolymer increases, tensile strength and elongation at break increase and reach a leveling off. 

S. The diffusion coefficients of gases in glassy polymer membranes are strong functions of the penetrant gas concentration in the membranes (or of the gas pressure), and depend also on polymer morphology (crystallinity, orientation), crosslinking, and chain mobility. The chain mobility depends, in turn, on the polymer free volume, the... 

The best and most direct methods to observe the hydration of a macromolecule are X-ray and neutron diffraction analyses carried out at high resolution to better than 1.8 A. In the crystals of proteins, the macromolecules are heavily hydrated so that between 20Vo and 909o of the total volume are solvent. In fact, despite their well-defined crystal morphology, crystalline proteins more resemble concentrated protein solutions than the solid state. 

The problem of the nature of the conducting state in polyacetylene cannot be considered without a close investigation of the real nature of the samples, including characteristics such as morphology, crystallinity, defect concentration, chain length, and so on. In the early 1980s the studies were concerned with (CH) obtained by the Shirakawa method. The doping level y appeared to be a crucial parameter. As a function of y, basically... 

This survey of the pharmaceutical aspects of polymers and macromolecules emphasises their use in formulation. It stresses the key features of polymers - their molecular weight distribution and their versatility in terms of their morphology, crystallinity, solubility and performance. 

For a given polymeric structure, the morphology (crystallinity and orientation), formulation (additives, fillers and impurities), humidity (especially for polar polymers), temperature, and pressure, are the most important factors which affect the thennal conductivity. References [1-8] review many of these factors. In addition, see Bigg [14] and Ross et al [15] for detailed treatments of the effects of fillers and of pressure, respectively, on thermal conductivity. 

Various theories and empirical expressions are available (14. 16) for estimating K for special situations. Obviously, this factor will depend on the volume fraction of impermeable particles, their shape, and their arrangement in space, that is, morphology. Crystalline polymers are much better barriers to permeation than are equivalent amorphous polymers by virtue of the obstruction to transport caused by their crystallites. Often their resistance to permeation can be further improved by stretching or drawing so that the crystals are converted from a random arrangement to a more ordered array such as that illustrated in Figure 4. 

Mesoscale crystalline morphology, crystallinity, and molecular orientation in these deposited thin films strongly depend on molecular properties [17,18], chemical nature of the solvent, and processing condition, resulting in very different field-effect mobilities [15,23,36]. Specifically, due to heterogeneous surface-induced (epitaxy) crystal growth as a nature of semicrystalline polymers, fine control of substrate properties and solvent evaporation rate tends to yield favorable molecular orientation of these polymers (i.e., edge-on structure with respect to dielectric substrates) in solution-deposited films [24,66]. 

Like other semi-crystalline polymers, the glass transition of PLA is influenced by physical aging [150], crystallinity, morphology, and impurities [151, 152]. Other properties of PLA such as the mechanical strength also depend on the morphology, crystallinity, and orientation. It was found by Wong et al. [153] that the orientation of the crystalline phase was always higher than that of the amorphous phase. 

Each kind of CNs has a characteristic size, aspect ratio, morphology, crystallinity, crystal structure, and properties. Figure 13.7a shows the microstructure of the T-CNs prepared by acid hydrolyzation. T-CNs have a high-aspect-ratio [20-30 nm wide, 0.5-4 pm in length], are about 100% cellulose, highly crystalline [85-100%] and containing a high fraction of crystal structure [ 90%] [19, 28-30]. After sonicatlon, the T-CNs became much... 

In addition to the dependence on constitutional parameters, the rate and extent of dyeing also depend significantly on the morphology, crystallinity, and molecular orientation of the fiber, for any of the processes considered [353]. 

M. Eslamian, N. Ashgriz Effect of precursor, ambient pressure, and temperature on the morphology, crystallinity, and decomposition of powders prepared by spray pyrolysis and drying, Powder Technol. 167 (3), 149-159 (2006a). 

Fourier transform infrared (FTIR) spectroscopy is a powerful and reliable technique that for many years has been an important tool for investigating chemical processes and structures. In the polymer fields, FTTR data is used in order to study characterization of chemical bonds, polymer microstructure, chain conformation, polymer morphology, crystallinity and etc, consequently is useful in SPR studies. 

As will be described in the following sections, property (size and size distribution, morphology, crystallinity, and so on) control implies precise process control, i.e., control of reaction conditions. Here, a microreactor is a useful tool that can control reaction conditions flexibly and accurately. Furthermore, a microreactor can be an easy setup for online reaction analyzer, in particular allowing in situ observation of nanoparticle properties, for example, optical spectroscopy. 

Catalyst morphology (crystallinity, porosity, external and internal surface). 

PLA hydrolysis is an important phenomenon since it leads to chain fragmentation [4, 7, 39], and can be associated with thermal or biotic degradation. This process can be affected by various parameters such as the PLA structure, its molecular weight and distribution, its morphology (crystallinity), the shape of its sanples and its thermal and mechanical history (including processing), as well as, of course, the hydrolysis conditions. Hydrolytic... 

Electrospinning of biodegradable polylactide/hydroxyapatite nanofibers study on the morphology, crystallinity structure and thermal stability. Polym. Degrad. Stab., 97, 2052-2059. 

The main physicochemical characteristics of the rice husks and the products of its thermal degradation in different atmosphere used as fillers of polymers are morphology, crystalline, or amorphous state, surface reactivity functional groups, thermal stability, and pore structure. Some of them are presented in Table 13.1, and compared with those of Aerosil A200 (AR), Degussa AG, Germany. 

What Is Polymer Morphology Crystalline versus Amorphous Materials... 

The physical characteristics of an in -polymerized PEDOT film are affected by a variety of factors. Variables in the synthetic method used to manufacture PEDOT will affect the resulting polymer morphology, crystallinity, doping level, conductivity and molecular weight. In general, the more uniform or crystalline a PEDOT film is, the higher wiU be its conductivity a. Values of a = 500-700 Scm are achievable [47]. 

Each method yields powders suitable for sintering but with different morphologies, crystallinity, specific surface area, oxygen, carbon and impurity contents, all of which can significantly influence the rate of densification. The ideal powder should have the following characteristics ... 

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