Poly chemical gels

R. S. Hadand, R. K. Pmd homme, Poly electrolyte Gels, Properties and Applications, American Chemical Society, Washiagton, D.C., 1992. 

Fig. 6.16 NSE relaxation curves obtained from a 16% volume fraction poly(fluorosilicone) gel in acetone using tbe bigb resolution NSE spectrometer INI5 at tbe ILL, Grenoble. Tbe existence of plateaus that represent tbe level of excess scattering from static inhomogenieties at low wave vector Q is clearly visible. Tbe decay rates times of tbe dynamic parts yield tbe collective diffusion coefficient of tbe gel. (Reprinted with permission from [291]. Copyright 2002 American Chemical Society)...

The temperature dependence of the friction coefficient normalized by the viscosity of the water, f/rj, is given in Fig. 10. The solid symbols are used in the increasing of the temperature and the open symbols are used in the lowering of the temperature. The values of the viscosity of the water, tj(T), are taken from the literature. For the chemically cross-linked gels, such as the poly(acrylamide) gel, the friction, f/rj, is independent of the temperature which has been already shown in previous section. It is, however, found from this figure that the friction... 

Chemical gels are covalently cross-linked polymer networks, featuring very high viscosity and well-defined pore structure. Polyacrylamide is the most widely used chemical gel material, usually cross-linked with N,N-methylene-bisacryl-amide (BIS). The pore size of the gel is determined by the relative concentration of monomer and cross-linker used during polymerization (%T, total monomer concentration and %C, cross-linker concentration as a percent of the total monomer and cross-linker concentration [34]). Highly cross-linked ( 5%C) poly-... 

This section is concerned with the poly(methacrylic acid) (PMAA) gel as the chemical gel where crosslinkages are composed of chemical bonds. The hydro-swollen polyelectrolyte gels, such as the PMAA, deform and change their volume in response to the change in environment as described in Section... 

Evidence for electrostatic repulsion has been adduced from the small retention volumes for proteins in pure water on recently developed crosslinked poly(vinylalcohol) gels (84). Lysozyme and chymotrypsinogen elute late from these GS" columns (Asahi Chemical Ind. Co.). On the other hand, the elution volumes of BSA and myoglobin are essentially unchanged over the ionic strength range ca. 0,3 M - 0.8 M. 

Potta, T., Chun, C., Song, S.C., 2009. Chemically crossUnkable thermosensitive poly-phosphazene gels as injectable materials for biomedical applications. Biomaterials 30 (31), 6178-6192. 

Uses organic intermediate cross-linking agent for preparation of polyacrylamides in preparing poly-acrylamide gel for electrophoresis, chemical grouting and other purposes in NAPP and Nyloprint UV-cured printing plates A... 

The presence of residual toxic chemical species, such as the electrolyte (HF) itself and the etch by-products silicon tetrafluoride (Sip4) and hexafluorosilicic acid (H2S1F6), all water soluble, must be considered after anodization (Koynov et al. 2011) and, likewise, any residual electrolyte additives. The secondary reaction of H2Sip6 with water in the aqueous environment of the pores may produce metasilicic acid (H2Si03) - this can polymerize to a less-soluble (poly-silicate) gel (and ultimately a solid), which may entrap the residual toxic species mentioned above (Koynov et al. 2011). The complete removal of all toxic species is a prerequisite for most applications and is particularly important for the biomedical field. 

Poly(2-aciylamido-2-methylpropane sulfonic acid) [PAMPS] Synthetic, organic, vinyl polymer Chemical gel Hydrogel... 

One of the first PEO chemical gels cmistructed through triazole cross-linking was disclosed by HUbom (Scheme 8) [47]. Poly(vinyl alcohol) derivatives with acetylene 25 and azide side chains 26 were prepared and cross-Unked to produce a hydiogelating network 27. For comparative study, a similar type of hydrogelator 29... 

The chemical adsorption of a relatively high molecular weight neutral polymer (poly(succinimide), M = 13000) on aminopropyl-Vydac 101 TP silica gel was applied by Alpert [47, 48] to prepare a reactive composite support for use in cation-exchange [47] and hydrophobic-interaction [48] chromatography of pro-... 

In the field of soluble conducting polymers new data have been published on poly(3-alkylthiophenes " l They show that the solubility of undoped polymers increases with increasing chain length of the substituent in the order n-butyl > ethyl methyl. But, on the other hand, it has turned out that in the doped state the electro-chemically synthesized polymers cannot be dissolved in reasonable concentrations In a very recent paper Feldhues et al. have reported that some poly(3-alkoxythio-phenes) electropolymerized under special experimental conditions are completely soluble in dipolar aprotic solvents in both the undoped and doped states. The molecular weights were determined in the undoped state by a combination of gel-permeation chromatography (GPC), mass spectroscopy and UV/VIS spectroscopy. It was established that the usual chain length of soluble poly(3-methoxthythiophene) consists of six monomer units. 

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