Poly inverse

Materials that typify thermoresponsive behavior are polyethylene—poly (ethylene glycol) copolymers that are used to functionalize the surfaces of polyethylene films (smart surfaces) (20). When the copolymer is immersed in water, the poly(ethylene glycol) functionaUties at the surfaces have solvation behavior similar to poly(ethylene glycol) itself. The abiUty to design a smart surface in these cases is based on the observed behavior of inverse temperature-dependent solubiUty of poly(alkene oxide)s in water. The behavior is used to produce surface-modified polymers that reversibly change their hydrophilicity and solvation with changes in temperatures. Similar behaviors have been observed as a function of changes in pH (21—24). 

Tempera.ture Effect. Near the boiling point of water, the solubiUty—temperature relationship undergoes an abmpt inversion. Over a narrow temperature range, solutions become cloudy and the polymer precipitates the polymer caimot dissolve in water above this precipitation temperature. In Figure 4, this limit or cloud point is shown as a function of polymer concentration for poly(ethylene oxide) of 2 x 10 molecular weight. 

Poly(vinyl alcohol) can be recovered from the desizing Hquid by means of commercial ultrafiltration equipment. Recovery rates and effluent losses ate inversely proportional to the PVA solution viscosity and independent of the degree of hydrolysis. 

IBI 1,4-Polyisoprene 1,4-Polybutadiene Poly(ethylene-co- propylene Polyethylene Inverse block polymer— properties dependent on composition... 

Several selective interactions by MIP membrane systems have been reported. For example, an L-phenylalanine imprinted membrane prepared by in-situ crosslinking polymerization showed different fluxes for various amino acids [44]. Yoshikawa et al. [51] have prepared molecular imprinted membranes from a membrane material which bears a tetrapeptide residue (DIDE resin (7)), using the dry phase inversion procedure. It was found that a membrane which contains an oligopeptide residue from an L-amino acid and is imprinted with an L-amino acid derivative, recognizes the L-isomer in preference to the corresponding D-isomer, and vice versa. Exceptional difference in sorption selectivity between theophylline and caffeine was observed for poly(acrylonitrile-co-acrylic acid) blend membranes prepared by the wet phase inversion technique [53]. 

Poly(VPGVG) (Fig. 6) has been smdied most thoroughly and it was shown that it exhibits an inverse phase transition. The biopolymer undergoes phase separation from solution upon increasing temperature, resulting in a p-spiral structure and simultaneous release of water molecules associated with the polymer chain (Fig. 7). 

Fig. 7 (a) Recurring P-tum found in poly(VPGVG). (b) P-spiral structure adopted by the poly(VPGVG) upon raising the temperature above the inverse transition temperature. Reprinted from [22] with permission from Elsevier, copyright 1992... 

After expression of poly(VPGXG) genes, the biopolymer can easily be purified from a cellular lysate via a simple centrifugation procedure, because of the inverse temperature transition behavior. This causes the ELPs to undergo a reversible phase transition from being soluble to insoluble upon raising the temperature above the and then back to soluble by lowering the temperature below Tt (Fig. 9). The insoluble form can be induced via addition of salt [27]. The inverse transition can... 

Resistance to acid erosion depends on brand and varies from 0 04 to 0-54% per hour (Setchell, Teo Kuhn, 1985 Wilson et al, 1986a Walls, McCabe Murray, 1988). It would appear that cements based on copolymers of acrylic and maleic acids are less durable than those based on poly(acrylic acid). The extent of erosion varies inversely with the time allowed for the cement to cure prior to exposure (Walls, McCabe Murray, 1988). 

J. P. and Moller, M. (2001) Excimer laser ablation of gold-loaded inverse polystyrene-block-poly (2-vinylpyridine) micelles. Appl. Phys. A, 72, 679-685. 

A second project [10] was based on the production of Pd nanocluster inside poly-methacrylic acid (8%mol)-A,iV-di-methylacrylamide (88 % mol)-A, A -methylenebisacrylamide (4% mol). ISEC (Inverse Size Exclusion Chromatography) analysis of the resin in water in terms of cylindrical pores [7]... 

From these results it is reasonable to conclude that no inversion in the order of the chemical shifts of the tertiary carbon atoms belonging to the different triads occurs from the starting PV0CC1 to the poly(vinyl phenyl carbonate). Moreover the chemical modification of PV0CC1 by phenol does not induce any degradation of the polymer. 

Fig. 10. Amide end-capped poly(hexafluoropropy-lene oxide) used for the inverse emulsion polymerization of acrylamide in C02 [123]...

Foams for woodland and grass fire-fighting have been developed with low drainage (water loss from foam) and high expansion (volume of foam per volume of starting liquid), two parameters traditionally considered to be inversely proportional. The stabilizing additive is poly (methyl vinyl ether/maleic anhydride), thought to cross-react with fatty alcohol components of the foam base via the anhydride function. 

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