안티푸라민-에스^® 로션의 레올로지 특성 연구

국화윤,송기원,Kuk, Hoa-Youn,Song, Ki-Won 한국약제학회 2009 Journal of Pharmaceutical Investigation Vol.39 No.3

Using a strain-controlled rheometer [Advanced Rheometric Expansion System (ARES)], the steady shear flow properties and the dynamic viscoelastic properties of $Antiphlamine-S^{(R)}$ lotion have been measured at $20^{\circ}C$ (storage temperature) and $37^{\circ}C$ (body temperature). In this article, the temperature dependence of the linear viscoelastic behavior was firstly reported from the experimental data obtained from a temperature-sweep test. The steady shear flow behavior was secondly reported and then the effect of shear rate on this behavior was discussed in detail. In addition, several inelastic-viscoplastic flow models including a yield stress parameter were employed to make a quantitative evaluation of the steady shear flow behavior, and then the applicability of these models was examined by calculating the various material parameters. The angular frequency dependence of the linear viscoelastic behavior was nextly explained and quantitatively predicted using a fractional derivative model. Finally, the strain amplitude dependence of the dynamic viscoelastic behavior was discussed in full to elucidate a nonlinear rheological behavior in large amplitude oscillatory shear flow fields. Main findings obtained from this study can be summarized as follows : (1) The linear viscoelastic behavior is almostly independent of temperature over a temperature range of $15{\sim}40^{circ}C$. (2) The steady shear viscosity is sharply decreased as an increase in shear rate, demonstrating a pronounced Non-Newtonian shear-thinning flow behavior. (3) The shear stress tends to approach a limiting constant value as a decrease in shear rate, exhibiting an existence of a yield stress. (4) The Herschel-Bulkley, Mizrahi-Berk and Heinz-Casson models are all applicable and have an equivalent validity to quantitatively describe the steady shear flow behavior of $Antiphlamine-S^{(R)}$ lotion whereas both the Bingham and Casson models do not give a good applicability. (5) In small amplitude oscillatory shear flow fields, the storage modulus is always greater than the loss modulus over an entire range of angular frequencies tested and both moduli show a slight dependence on angular frequency. This means that the linear viscoelastic behavior of $Antiphlamine-S^{(R)}$ lotion is dominated by an elastic nature rather than a viscous feature and that a gel-like structure is present in this system. (6) In large amplitude oscillatory shear flow fields, the storage modulus shows a nonlinear strain-thinning behavior at strain amplitude range larger than 10 % while the loss modulus exhibits a weak strain-overshoot behavior up to a strain amplitude of 50 % beyond which followed by a decrease in loss modulus with an increase in strain amplitude. (7) At sufficiently large strain amplitude range (${\gamma}_0$>100 %), the loss modulus is found to be greater than the storage modulus, indicating that a viscous property becomes superior to an elastic character in large shear deformations.

안티푸라민-에스(R) 로션의 레올로지 특성 연구

국화윤 ( Hoa Youn Kuk ),송기원 ( Ki Won Song ) 韓國藥劑學會 2009 Journal of Pharmaceutical Investigation Vol.39 No.3

Rheology of concentrated xanthan gum solutions: Oscillatory shear flow behavior

송기원,국화윤,장갑식 한국유변학회 2006 Korea-Australia rheology journal Vol.18 No.2

Nonlinear Viscoelastic Behavior of Concentrated Xanthan Gum Systems in Large Amplitude Oscillatory Shear (LAOS) Flow Fields : Fourier Transform Rheology

안혜진,국화윤,송기원,Ahn, Hye-Jin,Kuk, Hoa-Youn,Song, Ki-Won The Korean Fiber Society 2017 한국섬유공학회지 Vol.54 No.5

The present study has been performed to quantitatively characterize the nonlinear rheological behavior of concentrated xanthan gum systems in large amplitude oscillatory shear (LAOS) flow fields by means of the methodology of Fourier transform (FT) rheology. Using an Advanced Rheometric Expansion System (ARES), the dynamic viscoelastic behavior of aqueous xanthan gum solutions with different concentrations has been experimentally investigated in LAOS flow conditions with a various combination of several fixed strain amplitudes and constant angular frequencies. The nonlinear viscoelastic functions were derived from the Fourier spectra of stress responses, and then the fundamental and higher harmonic contributions were calculated from discrete Fourier transform (DFT). The nonlinear viscoelastic behavior was interpreted by displaying 3D plots, and then the effects of strain amplitude and angular frequency on the nonlinear behavior were discussed in depth. A comparison of the experimentally obtained stress response with the stress waves calculated from higher harmonic nonlinear viscoelastic functions was made to clarify the role of higher harmonic contributions. The main findings obtained from this study are summarized as follows : (1) When the strain amplitude becomes larger than a critical value of 50%, the higher nonlinear viscoelastic functions must be considered to explain the nonlinear viscoelastic behavior. However, the fundamental stress amplitude is dominantly larger than those of higher harmonics. (2) As the strain amplitude is increased, the fundamental stress amplitude is steeply increased within the linear viscoelastic region beyond which followed by an approximately constant magnitude at large deformations. This strain dependence may be explained as a distinction between linear and nonlinear viscoelastic behavior. (3) When the strain amplitude exceeds a critical value of 50%, the higher stress amplitudes are sharply increased with an increase in strain amplitude at large deformations, indicating that the higher stress harmonics exert an influence on the nonlinear viscoelastic behavior. (4) In order to interpret the complicated nonlinear viscoelastic behavior occurring at large deformations, the fundamental terms as well as the higher harmonics of phase angles defined at the odd terms should be deliberated for a quantitatively advanced analysis. (5) An overall shape of the experimentally obtained stress response is strongly affected by the higher harmonic contributions. As the angular frequency is decreased, a more distorted and a sharper stress waveform is observed at LAOS deformations. (6) A distorted stress waveform is qualitatively inclined to the left side with respect to a sinusoidal curve. In order to explain the nonlinear viscoelastic behavior of concentrated xanthan gum systems in LAOS flow fields, the nonlinear viscoelastic functions from the first to at least seventh harmonics should be considered for an accurate analysis.

Nonlinear Viscoelastic Behavior of Concentrated Xanthan Gum Systems in Large Amplitude Oscillatory Shear (LAOS) Flow Fields : Stress Waveform and Lissajous Pattern Analysis

안혜진,국화윤,이지석,송기원,Ahn, Hye-Jin,Kuk, Hoa-Youn,Lee, Ji-Seok,Song, Ki-Won The Korean Fiber Society 2016 한국섬유공학회지 Vol.53 No.5

The objective of the present study is to phenomenologically characterize the nonlinear rheological behavior of concentrated xanthan gum systems in large amplitude oscillatory shear (LAOS) flow fields by means of stress waveform and Lissajous pattern analysis. Using an Advanced Rheometric Expansion System (ARES), the dynamic viscoelastic behavior of aqueous xanthan gum solutions with different concentrations has been experimentally investigated in LAOS flow conditions with a various combination of several fixed strain amplitudes and constant angular frequencies. The main findings obtained from this study are summarized as follows: (1) When a sinusoidal deformation with large strain amplitude is applied, a distorted and nonsinusoidal but symmetrical stress response waveform is observed with time. (2) A saw-tooth shaped stress signal detected at large strain amplitudes may arise from a unique microstructure of xanthan polymer chains. A small peak of stress wave appearing at the position of maximum and minimum stress represents a nonlinear viscous nature of concentrated xanthan gum systems in LAOS flow fields. (3) As an increase in polymer concentration, the shape of stress wave becomes sharper and more distorted. This trend may be explained by an increase in structural density. (4) As a decrease in angular frequency, the stress wave exhibits a more distorted shape and both of the maximum and minimum peaks of a saw-tooth shaped stress response becomes more dominant. (5) At relatively small strain amplitudes, the Lissajous patterns (stress versus strain rate loops) show an elliptical form and their normalized ones are coincident with each other. When larger strain amplitudes are applied, however, the Lissajous patterns are noticeably nonelliptical, and moreover, as the strain amplitude is further increased, the tips of loops become more pointed with exhibiting a characteristic "S" shape.