The rheological behavior of collagen dispersion/poly(vinyl alcohol) blends

Guoying Li,Guoli Lai,Zongliang 한국유변학회 2007 Korea-Australia rheology journal Vol.19 No.2

Blends of collagen dispersion (COL) with poly(vinyl alcohol) (PVA) in different weight ratios were investigated by oscillatory rheometry, Fourier transform-infrared spectroscopy and scanning electron microscopy. It was found that even with 80% of PVA, the COL/PVA blends behaved more like collagen dispersion than pure PVA solution in the dynamic thermal and frequency processing, for instance, a dominant elastic appearance (G'>G"), a similar shear thinning behavior and the thermal denaturation below 40C. However, influence on the blend behaviour by PVA was noticeable, for instance, an increase of dynamic denaturation temperature, the decreasing intensity of amide I, II and III bands as well as the diminishing irregular pores on the surface of blends. The interaction between collagen and PVA could be observed, especially at the regions with low content or high content of PVA.

3D Analysis on Surrounding Soil Stability of Shaft Boring Machine Based on Plastic Limit Equilibrium Theory

Chao Li,Tao Li,Zhongqi Shi,Jinhui Li,Guoye Jing 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11

Shaft boring machine (SBM) plays a significant role in mechanized construction of deep and large shafts. However, surrounding soil instability of SBM pose great threats to the shaft construction. Therefore, it is necessary to analyse the soil stability underlying SBM’s gripper. On the basis of the first SBM (MSJ5.8/1.6D) that independently developed in China, the interaction between the SBM’s gripper and surrounding soil is investigated. According to the failure mode of the shaft obtained by numerical simulation, the geometry of the failure surfaces is first derived, and the stresses distribution on the failure surfaces are clearly presented. Then, the ultimate bearing capacity formula of the surrounding soil underlying SBM’s gripper is derived based on plastic limit equilibrium theory with Mohr-Coulomb criterion. The change rules of bearing capacity factors and the influence rules of basic parameters in this formula are obtained. Finally, the theoretical values in typical soils are compared with those from the numerical simulation to illustrate the rationality of the formula. The results of this investigation not only provide an advanced method for evaluating the surrounding soil stability of SBM in shaft construction, but also provide guidelines for the design and construction risk control of SBM.

Hybrid nanofiltration membranes prepared by a simultaneous synthesis method for precise molecular separation

Chenwei Li,Guoying Feng,Zhiguo Yan,Shaoping Li,Man Xu,Cunwen Wang,Yanbo Li 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-

Incorporation of nanofillers is an option to break through the trade-off of nanofiltration membranes. Inthe present work, a simultaneous synthesis method, ZIF and selective layer formed in one step, was proposedto prepare hybrid nanofiltration membrane. Co2+ ions pre-assembled on hydrolyzed polyacrylonitrile(PANH) support provided nucleation sites for ZIF-67 formation. The growth of ZIF-67 and theformation of polyethyleneimine (PEI) selective layer on the support completed in one step through codepositingof a solution of PEI and Hmim (2-methylimidazole). The feasibility of the simultaneous synthesismethod was verified by using different supports, PEIs, and the precursor concentrations. All resultsshow that ZIF-67 incorporation improved the water permenace, without significant compromising ofmembrane rejection. At an optimized condition, the obtained hybrid composite membrane showed highpermeance of 35 L/(m2*h*bar) and rejection of 93% toward PEG 200. The permeance increased by about150%–200% compared with the membrane without ZIF-67. Meanwile, the rejections of salts of the hybridmembrane were very low, exhibiting outstanding organic selectivity.

Rheological behavior of acylated pepsin-solubilized collagen solutions: Effects of concentration

Conghu Li,Lian Duan,Zhenhua Tian,Wentao Liu,Guoying Li,Xiaoping Huang 한국유변학회 2015 Korea-Australia rheology journal Vol.27 No.4

Effects of concentration on the rheological behavior of acylated pepsin-solubilized collagen solutions were investigated by steady shear tests, dynamic frequency sweep, creep tests and thixotropic loop measurements in this paper. The results showed that both acylated collagen and native collagen solutions exhibited the typical pseudoplastic behavior and displayed shear thinned behavior with the increase of shear rate. With the increase of acylated collagen concentrations from 5 to 10 mg/mL, shear viscosity, elasticity modulus (G'), viscous modulus (G''), complex viscosity (η*), and the ability to resist deformation increased due to the physical entanglement, whilst loss tangent (tan δ) decreased. Additionally, with the increase of acylated collagen concentrations, the area of thixotropic loop increased from 6.94 to 44.40 watts/m3, indicating that the thixotropy of acylated collagen increased. Compared with native collagen solution, acylated collagen solution had stronger shear viscosity, η*, thixotropy, and ability to resist deformation. Furthermore, Power law model, Carreau model, Cross model, Leonov model and Burger model, were suitable for the fitting of the experimental data

Effects of NaCl on the rheological behavior of collagen solution

Duan, Lian,Li, Jiheng,Li, Conghu,Li, Guoying 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.3

The effects of NaCl on the rheological properties of collagen solutions were studied by steady shear test and thixotropic loop test. The results showed the rheological properties of the collagen solutions with different NaCl concentrations were quite different. With low NaCl concentrations (0 to 0.1 mol/L), the collagen solutions exhibited salting in effect. The pseudoplastic behavior of the solutions became weak, while the thixotropy became strong. The collagen solutions with high NaCl concentrations (0.1 to 0.3 mol/L) exhibited salting out effect. The pseudoplastic behavior of the solutions became strong and the thixotropy had no obvious variation. In addition, Ostwald de-waele model, Carreau model and Herschel-Bulkley model were used to fit the experimental data. The superimposed experimental data and the model curves indicated the suitability of the models used, except for the up curves in thixotropic loop test.

Effects of NaCl on the rheological behavior of collagen solution

Lian Duan,Jiheng Li,Conghu Li,Guoying Li 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.3

The effects of NaCl on the rheological properties of collagen solutions were studied by steady shear test and thixotropic loop test. The results showed the rheological properties of the collagen solutions with different NaCl concentrations were quite different. With low NaCl concentrations (0 to 0.1 mol/L), the collagen solutions exhibited salting in effect. The pseudoplastic behavior of the solutions became weak, while the thixotropy became strong. The collagen solutions with high NaCl concentrations (0.1 to 0.3 mol/L) exhibited salting out effect. The pseudoplastic behavior of the solutions became strong and the thixotropy had no obvious variation. In addition, Ostwald de-waele model, Carreau model and Herschel-Bulkley model were used to fit the experimental data. The superimposed experimental data and the model curves indicated the suitability of the models used, except for the up curves in thixotropic loop test.

Study on Anomalous Codeposition Phenomenon of CoNi Magnetic Films

Yundan Yu,Guoying Wei,Hongliang Ge,Li Jiang,Lixia Sun 한국자기학회 2017 Journal of Magnetics Vol.22 No.2

CoNi alloy films prepared from electrolytes with various concentrations of cobalt ions were studied in the paper. Influences of different cobalt ions concentrations on electrochemistry processes, components, microstructures, surface morphologies and magnetic properties of CoNi films were investigated. It was found that CoNi film plating was a kind of anomalous codeposition process. The percentage of cobalt content in CoNi films was higher than that of in the electrolyte. Moreover, with the rise of cobalt ions concentrations, the percentage of cobalt content in the samples increased gradually. CoNi films possessed crystal structures with four stronger diffraction peaks. However, CoNi films prepared from bath with higher cobalt ions possessed hcp structures which contributed to dendrite structures resulting in the increase of coercivity.

Rheological properties of fish skin collagen solution: Effects of temperature and concentration

Min Zhang,Yihui Chen,Guoying Li,Zongliang Du 한국유변학회 2010 Korea-Australia rheology journal Vol.22 No.2

To use collagen from freshwater fish skin as an alternative source of mammalian collagens for biomedical applications, we tested the rheological and structural properties of collagen from the skin of largefin longbarbel catfish (Mystus macropterus) by dynamic viscoelasticrheologimenteolFish skin collagen solution (FSCS) exhibited a sheor-thinning fedi behaMysr. The compllastiscosity (h*), loss tangent (tan d) and relaxic visc me of 1.5% FSCS decreased wies tkin ocrease of temperature. Also, tan d decreased wehaMythe relaxic visc me ocreased wies tkin ocrease of FSCS concentration. FSCS tiscconsider coymedicr stocon rhodulus (G'), loss hodulus (G"), h* tested and relaxic visc me and arus) by tan d teste tkaischose of bovine skin collagen solution (BSCS). Hdicver, FSCS behaMed wiesout regularity above 27.5oCi behtiowas in agreiment wies tkinisc me tkat tkindynamic denaturac viscemperature of thed collagen was approx mateoym29.5oC. Thes decreasedindicated tkat temperature and concentration ), ltococenols suitaconcfor isjusting FSCS tiscosity. The Arrhenius-typoce me-temperature superposition (TTS) was appliedCS tiisdition, tkinactitetion energy of 149.6KJ hol-1cfor 1.5% FSCS was calculated accor6KJ hentthe Arrhenius equation, indicatKJ ha weakby dntangliment effect amongal amongal amongal holeculeus (aischat amongal bovine skin collagen molecules, which was in agreement with the results from AFM measurement.

The rheological behavior of collagen dispersion/poly(vinyl alcohol) blends

Lai, Guoli,Du, Zongliang,Li, Guoying The Korean Society of Rheology 2007 Korea-Australia rheology journal Vol.19 No.2

Blends of collagen dispersion (COL) with poly(vinyl alcohol) (PVA) in different weight ratios were investigated by oscillatory rheometry, Fourier transform-infrared spectroscopy and scanning electron microscopy. It was found that even with 80% of PVA, the COL/PVA blends behaved more like collagen dispersion than pure PVA solution in the dynamic thermal and frequency processing, for instance, a dominant elastic appearance (G'>G"), a similar shear thinning behavior and the thermal denaturation below $40^{\circ}C$. However, influence on the blend behaviour by PVA was noticeable, for instance, an increase of dynamic denaturation temperature, the decreasing intensity of amide I, II and III bands as well as the diminishing irregular pores on the surface of blends. The interaction between collagen and PVA could be observed, especially at the regions with low content or high content of PVA.

Properties of alkali-solubilized collagen solution crosslinked by N-hydroxysuccinimide activated adipic acid

Chen, Yihui,Zhang, Min,Liu, Wentao,Li, Guoying 한국유변학회 2011 Korea-Australia rheology journal Vol.23 No.1

The effect of N-hydroxysuccinimide activated adipic acid (NHS-AA) on the properties of alkali-solubilized collagen solutions was examined. The residual amino group content in crosslinked collagen, determined by trinitrobenzensulfonic acid (TNBS) assay, was decreased with increasing NHS-AA concentration. The results from differential scanning calorimeter (DSC) indicated that the maximum denaturation temperature ($T_d$) of crosslinked collagen solution was about $4.2^{\circ}C$ higher than that of un-crosslinked collagen solution ($36.6^{\circ}C$). Moreover, the values of storage modulus (G'), loss modulus (G") and complex viscosity (${\eta}^*$), obtained by means of dynamic frequency sweeps, were increased as NHS-AA concentration added up to 1.5 mM, and then decreased slightly when further increased NHS-AA concentration. Besides, for collagen solution crosslinked with 1.5 mM NHS-AA, dynamic denaturation temperature ($T_{dd}$) was about $1.1^{\circ}C$ lower than $T_d$ ($40.8^{\circ}C$), and the Arrhenius-type time-temperature superposition (TTS) principle was applied to yield the activation energy to be $474.4kJmol^{-1}$.