Polymer bridging effect, soluble

Polymers such as EVA, are used as admixture because it modify the elastic modulus, toughness, permeability and bond strength to various substrates in cement and mortars [10]. The polymer forms a film that creates a network inside the cement matrix, partially covering hydrated and anhydrous cement particles, sealing pores and bridging microcracks. Besides, this addition also changes the hydration rate. Silva et al [11] compare the effects of two polymers a water soluble polymer (HPMC — hydroxypropylmethylcellulose) and a latex [EVA-poly(ethylene-co-vinyl acetate)] on... 

Water-soluble organic polymers, sueh as hydroxethylcellulose, have been used to slow the leak-off rate of clear brines into permeable formations. Fluid loss or leak-off, however, can be effectively controlled only by bridging the pore openings with rigid or semirigid particles of sufficient size and number. 

The hydrophobic microenvironments created on the cross-linked polystyrene may raise the intrinsic peptide-hydrolyzing activity of the metal center, as noted above. The microdomains created on the synthetic polymer may facilitate complexation of the protein substrate with the catalytic center. Possible inactivation of the metal center by formation of hydroxo- or oxo-bridged dimers or oligomers can be prevented upon immobilization of the metal center to a sohd support. Higher pH values inaccessible by a soluble metal complex can be attained by the corresponding immobilized metal complex. The enhancement in the proteolytic activity of the Cu(II) complex of cyclen upon attachment to the polystyrene may be attributed to some of these effects. 

The thermodynamic behavior of fluids near critical points is drastically different from the critical behavior implied by classical equations of state. This difference is caused by long-range fluctuations of the order parameter associated with the critical phase transition. In one-component fluids near the vapor-liquid critical point the order parameter may be identified with the density or in incompressible liquid mixtures near the consolute point with the concentration. To account for the effects of the critical fluctuations in practice, a crossover theory has been developed to bridge the gap between nonclassical critical behavior asymptotically close to the critical point and classical behavior further away from the critical point. We shall demonstrate how this theory can be used to incorporate the effects of critical fluctuations into classical cubic equations of state like the van der Waals equation. Furthermore, we shall show how the crossover theory can be applied to represent the thermodynamic properties of one-component fluids as well as phase-equilibria properties of liquid mixtures including closed solubility loops. We shall also consider crossover critical phenomena in complex fluids, such as solutions of electrolytes and polymer solutions. When the structure of a complex fluid is characterized by a nanoscopic or mesoscopic length scale which is comparable to the size of the critical fluctuations, a specific sharp and even nonmonotonic crossover from classical behavior to asymptotic critical behavior is observed. In polymer solutions the crossover temperature corresponds to a state where the correlation length is equal to the radius of gyration of the polymer molecules. A... 

Studies [41,47] have demonstrated that polyimides derived from ether-bridged aromatic diamines with -CF3 groups are soluble, high-temperature polymer materials with low moisture absorption, low dielectric constant, high optical transparency, and low birefringence. The effect of fluorene substitution on the dielectric constant of polyimides has been demonstrated for a broad spectrum of fluorene-containing diamine structures (Table 3.2). The... 

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