• Title/Summary/Keyword: Polymer adsorption

Search Result 19, Processing Time 0.085 seconds

Effect of polymer adsorption on film formation of silica/PVA suspension

  • Kim, Sun-Hyung;Sung, Jun-Hee;Ahn, Kyung-Hyun;Lee, Seung-Jong
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
    • /
    • 2009.10a
    • /
    • pp.79-84
    • /
    • 2009
  • Understanding the polymer adsorption in particle/binder/solvent system is important to achieve successful film products. While most of the reported work has dealt with the suspension microstructure, a few studies have focused on film formation. We investigated the effect of adsorption on film formation through measurement of adsorption amount in suspension and stress development in drying film with respect to mixing time ($t_m$). All of the adsorption amount (PVA), characteristic stress ($\sigma_{ch}$) exhibited similarities expressed by the form of $1-e^{t_m/{\tau}}$. The porous and non-unifonn dried film at short tm became close-packed and uniform with longer $t_m$. We found that polymer adsorption plays the key role in film fonnation as it introduces steric repulsion in suspension and suppresses the flocculation during solvent evaporation. We also found that the mixing time for the saturated polymer adsorption is the important variable to acquire the consolidated and uniform film microstructure.

  • PDF

A Theory of Polymer Adsorption from Solution

  • Lee, Woong-Ki;Pak, Hyung-Suk
    • Bulletin of the Korean Chemical Society
    • /
    • v.8 no.1
    • /
    • pp.19-26
    • /
    • 1987
  • A statistical thermodynamical treatment for polymer adsorption from solution is presented. The canonical partition function for the polymer solution in the presence of a surface or an impermeable interface is formulated on the basis of usual quasi-crystalline lattice model, Bragg-Williams approximation of random mixing, and Pak's simple treatment of liquid. The present theory gives the surface excess ${\Gamma}_{exc}$ and the surface coverage ${\phi}^s_2$ of the polymer as a function of the chain length x, the Flory-Huggins parameter x, the adsorption energy parameter $x_s$, and polymer concentration $v_2$. Present theory is also applicable to the calculation of interfacial tension of polymer solution against water. For the idealized flexible polymer, interfacial tensions according to our theory fit good to the experimental data to the agreeable degrees.

Effects of Polymer Adsorption on Stabilities and CMP Performance of Ceria Abrasive Particles

  • Shimono Norifumi;Kawaguchi Masami;Koyama Naoyuki
    • Transactions on Electrical and Electronic Materials
    • /
    • v.7 no.3
    • /
    • pp.112-117
    • /
    • 2006
  • In this paper we present that the effects of polymer adsorption on stabilities and CMP performance of ceria abrasive particles. Characterization of ceria abrasive particles in the presence of poly(vinyl pyrrolidone) (PVP) was performed by the measurements of adsorbed amounts of PVP, average sizes, and the back scattering intensities of the ceria abrasive particles as functions of PVP molecular weight and PVP concentration. The ceria abrasive particles in the presence of PVP were used to polish $SiO_2\;and\;Si_3N_4$ films deposited on Si wafers in order to understand the effect of PVP adsorption on chemical mechanical polishing (CMP) performance, together with ceria abrasive particles without PVP. Adsorption of PVP on the ceria abrasive particles enhanced the stability of ceria abrasive particles due to steric stabilization of the thick adsorbed layer of PVP. Removal rates of the deposited $SiO_2\;and\;Si_3N_4$ films by the ceria abrasive particles in the presence of PVP were much lower than those in the absence of PVP and their magnitudes were decreased with an increase in the concentration of free PVP chains in the dispersion media. This suggests that the CMP performance in the presence of PVP could be mainly controlled by the hydrodynamic interactions between the adsorbed PVP chains and the free ones. Moreover, the molecular weight dependence of PVP on the removal rates of the deposited films was hardly observed. On the other hand, high removal rate selectivity between the deposited films in the presence of PVP was not observed.

Polymer Adsorption and fiber Dispersion Stability of a Paper Stock Colloidal Suspension with a PAC-PAE Dual Polymer System (PAC-PAE 2중 고분자 내첨 지료의 고분자 흡착 및 교질 분산계의 안정성 연구)

  • 윤성훈;김태영;김덕기;송병규
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.35 no.2
    • /
    • pp.18-25
    • /
    • 2003
  • The adsorption of co-cationic dual polymer system was investigated as was the fiber dispersion stability of a paper stock suspension. Polyaluminum chloride(PAC) and polyamidoamine epichlorohy-drin(PAE) polymers were used as wet-end additives. The adsorbed amounts of PAE polymer in a wet stock were measured by using polyelectrolytic PCD titration. The sheet forming experiments were carried out in a standard handsheet machine. Fiber dispersion stability and relative retention were evaluated in terms of M/K non-uniformity index and sheet basis weight, respectively. The PAE polymer adsorption of Langmuir-isothermal type decreased with increasing PAC addition level. The combination of the two cationic polymers presumably exerts a site-blocking effect by the low molecular weight PAC which gives a partial charge neutralization at a minimum level of addition. From a thermodynamic view point of PAE adsorption, an increase in adsorption entropy and a decrease in train number suggests that the PAR polymer has an extended conformation structure that potentially leads to an enhancement of the fiber dispersion stability. This conclusion is supported by handsheet experiments that examined the PAC-PAE dual polymer effects on the sheet formation and retention.

The Effect of Cellulase on the Pore Structure of Cellulose Fibers

  • Park, Sun-Kyu;Venditti Richard A.;Abrecht David G.;Jameel Hasan;Pawlak Joel J.;Lee, Jung-Myoung
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
    • /
    • 2006.06a
    • /
    • pp.43-49
    • /
    • 2006
  • The surface and pore structure of cellulose fibers have a significant impact on the properties and performance in applications. Cellulase enzymatic hydrolysis of cellulose fibers can result in changes to the surface and pore structure thus providing a useful tool for fiber modification. This research characterizes these changes using various test methods such as fiber dimension, water retention value, hard-to-remove water content, freezing and non-freezing bound water content, polymer adsorption, and crystallinity index. For a high-dosage enzyme treatment (0.10 g/g), the fiber length was significantly decreased and the fibers were 'cut' in the cross direction, not in the axial direction. The swelling capacities as measured by the WRV and HR water content increased for the high-dosage treatment. Three independent measurements (non-freezing bound water, polymer adsorption, and crystallinity index) are in good agreement with the statement that the amorphous regions of cellulose fibers are a more readily available substrate relative to crystalline regions. Based on the experimental results obtained herein, a model was proposed to explain surface and pore structure modification of cellulose fibers via enzymatic treatment.

  • PDF

Polymer Adsorption at the Oil-Water Interface

  • Lee, Woong-Ki;Pak, Hyung-Suk
    • Bulletin of the Korean Chemical Society
    • /
    • v.8 no.5
    • /
    • pp.398-403
    • /
    • 1987
  • A general theory of polymer adsorption at a semi-permeable oil-water interface of the biphasic solution is presented. The configurational factor of the solution in the presence of the semi-open boundary at the interface is evaluated by the quasicrystalline lattice model. The present theory gives the feature of the bulk concentration equilibria between oil-water subsystems and the surface excesses of ${\Gamma}^{\alpha}$ and ${\Gamma}^\{beta}$ of the polymer segments as a function of the degree of polymerization $\gamma$, the Flory-Huggins parameter in $\beta$-phase $x_{\rho}^{{\beta}_{\rho}}$, the differential adsorption energy parameter in $\beta$-phase $x_{\sigma}^{{\beta}_{\rho}}$, the differential interaction energy parameter ${\Delta}x_{\rho}$ and the bulk concentration of the polymer in ${\beta}-phase ${\varphi}_2^{{\beta(*)}_2}$. From our numerical results, the characteristics of ${\Gamma}^{\alpha}$ are shown to be significantly different from those of ${\Gamma}^{\beta}$ in the case of high polymers, and this would be the most apparent feature of the adsorption behavior of the polymer at a semi-permeable oil-water interface, which is sensitively dependent on ${\Delta}x_{\rho}$ and r.

Theoretical Overview of Membrane Transport (막물질 이동의 이론적 고찰)

  • Park, Young
    • Membrane Journal
    • /
    • v.3 no.3
    • /
    • pp.94-107
    • /
    • 1993
  • Many researchers have discussed how membrane performance can be enhanced through an understanding of polymer science and engineering. The understandings of transport in porous membrane are used to achieve the isolation of certain components from mixtures. Particular emphasis is placed on the applicability of membrane separations for the isolation of macromolecules[1]. An awareness of membrane structure characteristics is required for the rational design of membranes for specific and/or new applications. This understanding rests on the knowledge of fields such as polymer thermodynamics[2], polymer adsorption [3, 4], diffusion in polymers[5, 6], reaction mechanism[7], and the dynamic behavior[8, 9] of polymer in porous membrane.

  • PDF

Composition Studies on the Aromatic Tobacco Varieties (Nicotiana tabacum L. ) : II. Characteristics of Headspace Vapors (향끽미종 잎담배 성분조성에 관한 연구 II. 헤드스페이스 휘발성 유기성분의 특성 조사)

  • Kim, Kyoung-Rae;Lee, Un-chul
    • Journal of the Korean Society of Tobacco Science
    • /
    • v.3 no.1
    • /
    • pp.1-10
    • /
    • 1981
  • Volatile compounds in the headspace vapors of five aromatic tobacco varieties have been examined us ins the polymer adsorption method and high- resolution glass capillary gas chromatography. The gas chromatographic profiles thus obtained were compared, and the aroma composition was found to be characteristic of each tobacco sample with significant differences in the concentrations of major components.

  • PDF

A Kinetic Consideration on the Selective Adsorption and Molecular Recognition by Molecularly Imprinted Polymer

  • Li, Wuke;Li, Songjun;Luo, Gang;Ding, Kerong
    • Bulletin of the Korean Chemical Society
    • /
    • v.28 no.8
    • /
    • pp.1346-1352
    • /
    • 2007
  • This article presents an original work on kinetically studying the selective adsorption and recognition by molecularly imprinted polymer (MIP). With S-naproxen as template, the imprinted polymer was prepared. The result indicates that the prepared polymer shows a more complicated sorption toward S-naproxen than toward its enantiomer R-naproxen. The rate constant in the case of template appears to be a variable. There are also significant deviations from the idealized Langmuir model. Related information indicates that these, in logic, can be a result of biomimic structural and functional complements between imprint and the template, which makes the polymer capable of selectively recognizing the imprint species.