Polymer spontaneous

For rigid-chain crystallizable polymers, spontaneous transition into the nematic phase is accompanied by crystallization intermolecular interactions should lead to the formation of a three-dimensional ordered crystalline phase. 

We next investigated the dealkylation of S-b-tBM with TMSI. Unlike the reaction with S-b-MM, it required only 4 hr at room temperature to completely cleave the t-butyl ester. Work-up under acidic conditions gave S-b-MA which was virtually identical by NMR, IR, GPC, and titration with that just described above. Likewise, neutralization with KOH resulted in quantitative conversion to S-b-MA.K. Although the initially formed product of the reaction of alkyl esters with TMSI is presumably the trimethylsilyl ester (1 7 ), we were not able to isolate or characterize this copolymer. It is known that trimethysilyl methacrylate and its polymers spontaneously hydrolyze even in moist air (19). Any traces of water in the methanol used to precipitate the reaction mixture would thus preclude isolation of the intermediate trimethylsislyl ester. 

Polymers spontaneously flex (or bend), and they can also extend. As pointed out by Oosawa and AsakuraS any polymer behaving like a uniform rod will have an elastic reversible) modulus for flexing that is given by the following relationship ... 

DNA is a relatively stable polymer. Spontaneous reactions such as deamination of certain bases, hydrolysis of base-sugar A-glycosyl bonds, radiation-induced formation of pyrimidine dimers, and oxidative damage occur at very low rates, yet are important because of cells very low tolerance for changes in genetic material. 

The active material in our herbicide is a liquid that does not mix with water. It can be dispersed as droplets with a mixer - in our case the droplets have to be about 0.3 mm in diameter (Figure 11-7). If you then let a polymer-rich phase form by coacervation, the polymer spontaneously wets the drop surface. It forms a liquid polymer layer around the drop. Cross-linking the polymer gives a solid capsule. 

Figure 4.28 a) Disentanglement of the polymer main chain from the membrane surface by hydrophilic spacers, often ethylene glycol oligomers, is the best means to synkinetize vesicles from amphiphilic polymers. Ordering of the amphiphiles must not be disturbed by their covalent connections, b) Folding of the ionene polymer spontaneously yields monolayer vesicle membranes. ... 

The DIVEMA copolymer has also been covalently linked to methotrexate (356). This polymer spontaneously released methotrexate from the polymer backbone by... 

To a solution of A vinylcarbazole in ethyl acetate is added 0.1-1% aqueous solution of perchloric acid. A yellow-orange color develops immediately and the polymer spontaneously precipitates to give a polymer of MW 600-2000 (cryo-scopically in QH ). 

Fourthly, but not least, when the concentration becomes sufficiently high, rodlike polymers spontaneously orient towards some direction, and form a liquid crystalline phase. It is this capability of forming a highly ordered phase that produces strong fibres. 

The most spectacular aspect in such a solution is that above a certain concentration, the polymers spontaneously align in a certain direction, and the solution becomes anisotropic without any external fields. Such a solution is called a liquid crystal. 

The results of the OWLS experiments (see Figure 3) indicate that the PLL-g-PEG polymer spontaneously adsorbed from a pH 7.4 buffered aqueous solution onto metal oxide surfaces. The example shown in Figure 3 involved the adsorption of PLL-g-PEG onto three different metal oxide surfaces, specifically, titanium, niobium, and silicon/titanium. Tbis adsorption process occurred rapidly and resulted in the formation of a layer of adsorbed polymer on the surface. Typically, for Sio4Tio602 smfaces, a layer with an adsorbed areal density of approximately 125 ng/cm formed, and 95% of the final observed mass was reached within the first 5 min. Similar behavior was observed for the two other metal oxide surfaces investigated (that is, niobium pentoxide and titanium dioxide). Although the adsorption kinetics were quite similar, the resulting amount of PLL-g-PEG adsorbed to the surface was different and depended on the characteristic isoelectric point of the metal oxide, as shown in Figme 4 and Table 4. 37,38,46.48,49... 

Because the metathesis catalysts used in this process are often nondiscriminating, the precursor polymer is an atactic mixture of cis- and trans-linkages. According to theoretical calculations, the elimination of the substituted benzene from Feast s precursor polymer is symmetry allowed [66]. At room temperature this precursor polymer spontaneously eliminates hexafluoroxylene, pro-... 

The persistence of acetylenyl moieties in the final polymer spontaneous polymerization was considered the final strong evidence of the existence of a very selective recognition process capable of pre-organizing the monomer molecules for spontaneous polymerization. 

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