Molecular structure, morphology

Structural steels, tellurium in, 24 425 Structure(s), see also Chain structure Chemical structures Cocontinuous structures Controlled structure Crystal structure Molecular structure Morphology Phase structure of carbon fibers, 26 737-739 detersive systems for, 8 413t HDPE, 20 157-162 LLDPE, 20 182-184, 203-205 polyesterether elastomer, 20 72-73 polyester fiber, 20 21 polyether antibiotics, 20 137-139 polyimide, 20 276-278 polymer, 20 395-405 protein, 20 449 PTT, 20 68t... 

The response of a polymer depends upon temperature, time scale of the experiment, and molecular structure, morphology, and composition. In... 

Characterization techniques were used to determine molecular mass, molecular structure, morphology, thermal as well as mechanical properties. Various techniques commonly used for characterization of PHB include FTIR,NMR, DSC,TGA, GPC, and AFM. 

Figure 1.1 Scheme of correlations between polymerization, molecular structure, morphology, processing conditions, and micro- or nanomechanical mechanisms of deformation and fracture depending on loading conditions, all of which determine the ultimate mechanical properties... 

With these contrasts in molecular structure, morphology and crystallinity between poly-1,6 and polyacetylene, we undertook a study of the oxidation (doping) of poly-1,6 to a conductive state. Indeed exposure to iodine vapor in vacuo at room temperature successfully raised the onductivity from an initial value of 10 s/cm to 10 to 10 s/cm over the period of one hour, a rate similar to that of polyacetylene. However, the conductivity-time curve proceeded through this maximum value and then decreased by about a factor of 10 before plateauing (Figure 1). 

Induction time depends on the type of polymer (molecular structure, morphology). Table 1.9, while the rate of oxygen absorption is proportional to the mass of the polymer and not to its surface. It decreases with increasing film thickness [52]. 

On the other hand, three sulfonated aromatic polymers with different seqnences, that is, alternating, random, and multiblock sequences (Figure 4.25), were studied in order to better understand the relationship between the molecular structure, morphology, and properties of the PEMs as a function of the RH [38]. 

Descriptors Polymers Optical variables measurement Powders Plastic films Molecular structure Morphology Proteins Casein Polypeptides Sodium compounds... 

While cooling the melt to solidify in a processing operation, alignment of molecules controlling the crystallinity and overall morphology depends on the molecular structural parameters of PEs. 

A reactive polymer (RP) is simply a device to alloy different materials by changing their molecular structure inside a compounding machine. True reactive alloying induces an interaction between different phases of an incompatible mixture and assures the stability of the mixture s morphology. The concept is not new. This technology is now capable of producing thousands of new compounds to meet specific design requirements. 

In order to get a quantitative idea of the magnitude of the effects of these temperature variations on molecular structure and morphology an experimental study was undertaken. Two types of polymerizations were conducted. One type was isothermal polymerization at fixed reaction time at a series of temperatures. The other type was a nonisothermal polymerization in the geometry of a RIM mold. Intrinsic viscosities, size exclusion chromotograms (gpc) and differential scanning calorimetry traces (dsc) were obtained for the various isothermal products and from spatially different sections of the nonisothermal products. Complete experimental details are given below. 

TEM is a direct analysis tool for knowing if metal clusters are present in catalytic solutions. This technique permits to define the size, structure, morphology and state of aggregation of the metal particles [11]. Hence, this technique can be in particular useful to identify nanoclusters in metal-catalysed reactions, using molecular complexes as catalytic precursors. But the catalytic activity of these observed nanoclusters must be further checked. 

A brief review is given of the important qualitative features of thermoplastic elastomers. Particular emphasis is given to the molecular structure, bulk morphology and interfacial character of these materials. Both equilibrium and nonequilibrium structures are discussed... 

Reversible network structure is the single most important characteristic of a thermoplastic elastomer. This novel property generally arises from the presence of a phase-separated morphology in the bulk material which in turn is dictated by the molecular structure, often of a block copolymer nature. A wide variety of synthetic methods can, in principle, produce endless varieties of thermoplastic elastomers this fact coupled with the advantageous processing characteristics of these materials suggest that the use of thermoplastic elastomers will continue to grow in the 1980 s. 

Fig. 32 Schematic representation of molecular structure and morphology observed in PS-fo-PB-fc-PS linear and star-block copolymers. Oblique lines between blocks for LN2 and ST2 indicate tapered transition of dissimilar blocks. From [102], Copyright 2003 Wiley...

Siskin, M. Kelemen, S. R. Eppig, C. P., et al., Asphaltene Molecular Structure and Chemical Influences on the Morphology of Coke Produced in Delayed Coking. Energy Fuels Published on Web Nov. 4th, 2006, pp. 1-8. 

The general principles of the structure of glassy polymers and their rubber-modified derivatives, and of the molecular and morphological parameters have been thoroughly investigated. 

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