Chemical microstructure

Koenig, J. L., Chemical Microstructure of Polymer Chains, Wiley, New York, 1980. 

Thiel, B.L., Kunkel, D.D., Viney, C. Physical and chemical microstructure of spider dragline a study by analytical transmission electron microscopy. Biopolymers 34 1089-1097, 1994. 

Such problems have led to a recognition of the importance of defect groups or structural irregularities.12 16 If we are to achieve an understanding of radical polymerization, and the ability to produce polymers with optimal, or at least predictable, properties, a much more detailed knowledge of the mechanism of the polymerization and of the chemical microstructure of the polymers formed is required.16... 

This chapter is primarily concerned with the chemical microstructure of the products of radical homopolymerization. Variations on the general structure (CHr CXY) are described and the mechanisms for their formation and the associated Tate parameters are examined. With this background established, aspects of the kinetics and thermodynamics of propagation are also considered (Section 4.5). 

Koenig JL (1980) Chemical microstructure of polymer chains. John Wiley Sons, New York... 

Faulkner, L. R., Chemical microstructures on electrodes, Chem. Eng. News, 27 February 1984, p. 28. 

The physico-chemical microstructural features leading to common classification... 

Fourier transform infrared microspectroscopy (FTIR) and Raman microspectroscopy provide quantitative information about the chemical microstructure of heterogeneous solid foods (Cremer and Kaletunq, 2003 Piot et al., 2000 Thygesen et al., 2003) without sample destruction. 

Cremer, D.R. and Kaletung, G. 2003. Fourier transform infrared microspectroscopic study of the chemical microstructure of corn and oat flour-based extrudates. Carbohydr. Polym. 52, 53-65. 

Pretzl M, Schweikart A, Hanske C, Chiche A, Zettl U, Horn A, Boker A, Fery A (2008) A lithography-free pathway for chemical microstructuring of macromolecules from aqueous solution based on wrinkling. Langmuir 24 12748-12753... 

On the other hand, it should be realized that radical copolymerization at heterogeneous conditions offers additional unique opportunities not available in homogeneous (solution) copolymerization. These include the intrinsic possibilities of exploiting the heterogeneities of the reaction system to control the chemical microstructure of the synthesized copolymers, making possible new paradigms for synthesis and production of polymeric materials. In this contribution, we discuss some new synthetic strategies, which have been developed in recent years to provide effective control of the chemical sequences. 

Thus, copolymers of the same composition can have qualitatively different sequence distributions depending on the solvent in which the chemical transformation is performed. In a solvent selectively poor for modifying agent, hydrophobically-modified copolymers were found to have the sequence distribution with LRCs, whereas in a nonselective (good) solvent, the reaction always leads to the formation of random (Bernoullian) copolymers [52]. In the former case, the chemical microstructure cannot be described by any Markov process, contrary to the majority of conventional synthetic copolymers [ 10]. 

The chemical microstructures of cis-polyisoprene (HR) vulcanised with sulfur and N-t-butyl-2-benzothiazole sulfenamide (TBBS) accelerator were studied as a function of extent of cure and accelerator to sulfur ratio in the formulations by solid-state 13C NMR spectroscopy at 75.5 MHz [29]. Conventional (TBBS/Sulfur=0.75/2.38), semi-efficient (SEV=1.50/1.50) and efficient (EV=3.00/1.08) vulcanisation formulations were prepared, which were cured to different cure states according to the magnitude of increase in rheometer torque. The order and types of the sulfurisation products formed are constant in all the formulation systems with different accelerator to sulfur ratios. However, the amount of sulfurisation has been found to vary directly with the concentration of elemental sulfur. 

Numerical micromagnetics, which may be based either on the finite difference or finite element method, resolve the local arrangement of the magnetization which arises from the interaction between intrinsic magnetic properties such as the magnetocrystalline anisotropy and the physical and chemical microstructure of the material. The numerical solution of the equation of motion also provides information on how the magnetization evolves in time. The time and space resolution of numerical micromagnetic simulations is in the order of nanometers and nanoseconds, respectively. 

Chemical microstructural analysis (CMA) method is based on reactivity of the cellulosic hydroxyl groups with diethylaminoethyl chloride under very mild basic conditions, which, to the best of our knowledge, does not further disrupt ordered regions. The cotton cellulose is reacted with diethylaminoethyl (DEAE) chloride as shown in Figure 5.24. 

This finite renormalization has two consequences. First, the nonuniver-sal parameters depend on both the microscopic system and the renormalized theory chosen. They thus have no direct microscopic meaning. Physical information is contained in the relative change upon changing the chemical microstructure or temperature, but not in the absolute values. Second, on a more technical level, numerical results of finite order calculations will differ for different renormalization schemes. This is a principle problem, unavoidable in low order calculations of scaling functions. Unambiguous results are foimd only for quantities not involving the nonuniversal constants, like exponents or critical ratios, or normalized scaling functions expressed in terms of RG-invariant variables. The function P pRa) (Eq. (11.52)) is an example. For such quantities the e-expansion is unique. This aspect will be discussed further in Sect. 12.4. 

Koc, H. and Wetzel, D.L (2007) Imaging local chemical microstructure of germinated wheat with synchrotron infrared microspectroscopy. Spectroscopy, 22 (10), 24-32. 

Panzer, D.D. (1999) Documenfrng the chemical microstructure in hard wheat variefies using infrared Microspectroscopy. MS thesis, Kansas State University, Manhattan, KS. 

Koenig JL (1980) Chemical microstructure of polymer chains. Whey, New York Kuchanov SI, Panyukov SV (1996) Statistical thermodynamics of heteropolymers and their blends. In Allen G (ed) Comprehensive Polymer Science, second suppl, chap 13. Pergamon Press, New York... 

It is obvious that the special characteristic of fluoropolymers for NMR is the incorporation of the F nucleus, which is in many ways particularly suitable for study and can act as a unique probe to examine the chemical microstructure, domain structure and mobility at the molecular level for these materials. However, some special techniques are frequently required for the best results from F NMR of solid polymers. These are fully described in Section 6.6. The net result of the difficulties encountered in obtaining high-resolution solid-state F spectra is that relatively few research papers to date have reported spectra with optimised resolution. Therefore, most reported F... 

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