Polymers dynamics of the nonfluoro,nano-brush repelling agent with self-stratifying property in water-based coatings

While perfluoroalkyl acids (PFAAs), also known as C8s, are used extensively in textile repellent coatings, concerns have arisen for their carcinogenicity and hazardous effects on the environment. In this study, a novel water-based, nonfluoro, and nanobrush textile repelling agent was prepared by conventional sol–gel chemistry using amorphous fumed silica and n-octyltriethoxysilane as the starting materials. Minimal interaction between the designed repelling agent and marketed water-based resins was confirmed using linear viscosity region (LVR) analysis and asymmetric-flow field-flow fractionation (AF4), suggesting the self-stratification potential of the repelling agent. More specifically, the repelling agent exhibited excellent compatibility and self-stratifying ability with a force-emulsified acrylic-based resin, affording a water contact angle of 104.3° when incorporated at 7% solid content. Performance tests carried out on thermoplastic polyurethane (TPU) revealed excellent adhesion (100/100) of a final formulation, and a significant increase in water contact angle from 80.1° to 103.8° after treatment. In addition, the fouling area after the removal of a submerged sample from a mixture of slurry, polymer, and oil decreased from 48 to 1% when the repelling agent was added. Moreover, the sludge-fouling property remained unchanged after 1000 cycles of abrasion. These findings demonstrate the potential of the described nonfluoro, nanobrush repelling agent as an environmentally safe alternative for use with commercial resins, in turn realizing a fully water-based hydrophobic coating. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48003.     

The Loss of Hydrophobic Polypeptides during Fermentation and Conditioning of High Gravity and Low Gravity Brewed Beer

The object of this study was to investigate the loss of hydrophobic polypeptides, which are important for foam quality and stability in finished beer. Loss of hydrophobic polypeptide due to fermenter foaming occurs during transfer of fermented wort since a gradient of hydrophobic polypeptides towards the surface is created during fermentation. Due to higher polyphenol levels in high gravity (20°Plato) wort, more hydrophobic polypeptides are lost due to cold break (cold trub) precipitation compared to low gravity (12°Plato) wort. Another important factor affecting the loss of hydrophobic polypeptides could be proteinase A activity during fermentation, especially in high gravity fermentation where the yeast is exposed the higher stress. During high gravity fermentation, where osmotic pressures are higher, ethanol levels become greater, and nitrogen‐carbohydrate ratios are lower, more proteinase A is released by the yeast. This release of proteinase A into fermenting wort could have implications for the foam stability of the finished product.     

溶胶-凝胶法制备疏水型SiO-2气凝胶

以正硅酸乙酯 (TEOS)为硅源 ,用三甲基氯硅烷 (TMCS)为疏水试剂 ,通过溶胶 凝胶法在室温下制备出疏水型SiO2 气凝胶。用傅立叶变温红外 (FT IR)、扫描电镜 (SEM)、透射电镜 (TEM)和吸水性能对疏水型SiO2气凝胶的结构和性能进行了研究     

锌(Ⅱ)-氨基酸配合物分子内配体间疏水作用

应用 p H电位滴定法研究了配合物 Zn( Aa) 2 [Aa-=L- val(缬氨酸根 ) ,L- phe(苯丙氨酸根 ) ,L- trp(色氨酸根 ) ,L- tyr(酪氨酸根 ) ]在水和 2 0 %、40 %及 60 %二氧六环 /水溶液中的稳定性 [t=2 5℃ ,c=0 .1 mol/L Na Cl O4]。配合物 Zn( Aa) 2 相对于母体配合物 Zn( Aa) + 稳定性用Δlog K=log KZn( Aa)Zn( Aa) 2 - log KZn Zn( Aa) 表示。结果表明 :与 L-丙氨酸 ( L- ala)配合物 Zn( L- ala) 2 相比 ,所有这些氨基酸配合物 Zn( Aa) 2 均具有相对较大的 Δlog K值 ,表明这些配合物分子内存在着额外的稳定化作用。这种稳定性化作用可能主要归因于配合物分子内氨基酸侧链之间的疏水作用 ,并且这种作用随着氨基酸侧链结构及溶剂极性变化而变化     

Calorimetric determination of the enthalpy change for the binding of methyl orange to poly(vinylpyrrolidone) in aqueous solution

Thermodynamic parameters have been determined for the interaction of methyl orange and poly(vinylpyrrolidone) in aqueous solutions containing tris, tris and hydrochloric acid, or water only. Enthalpy changes were determined by use of a flow microcalorimeter. Free energy changes were calculated from the results of equilbrium dialysis studies. The results are interpreted in terms of the behaviour of poly(vinylpyrrolidone) in these systems. Analysis of data shows that the hydrophobic interactions in the systems are in the order: tris > wateronly > tris-HC1.     

Surface tailoring of an ethylene propylene diene elastomeric terpolymer via plasma‐polymerized coating of tetramethyldisiloxane

In the research presented here, we explore the use of a low‐energy plasma to deposit thin silicone polymer films using tetramethyldisiloxane (TMDSO) (H(CH₃)₂? Si? O? Si? (CH₃)₂H) on the surface of an ethylene propylene diene elastomeric terpolymer (EPDM) in order to enhance the surface hydrophobicity, lower the surface energy and improve the degradation/wear characteristics. The processing conditions were varied over a wide range of treatment times and discharge powers to control the physical characteristics, thickness, morphology and chemical structure of the plasma polymer films. Scanning electron microscopy (SEM) shows that pore‐free homogeneous plasma polymer thin films of granular microstructure composed of small grains are formed and that the morphology of the granular structure depends on the plasma processing conditions, such as plasma power and time of deposition. The thicknesses of the coatings were determined using SEM, which confirmed that the thicknesses of the deposited plasma‐polymer films could be precisely controlled by the plasma parameters. The kinetics of plasma‐polymer film deposition were also evaluated. Contact angle measurements of different solvent droplets on the coatings were used to calculate the surface energies of the coatings. These coatings appeared to be hydrophobic and had low surface energies. X‐ray photoelectron spectroscopy (XPS) and photoacoustic Fourier‐transform infrared (PA‐FT‐IR) spectroscopy were used to investigate the detailed chemical structures of the deposited films. The optimum plasma processing conditions to achieve the desired thin plasma polymer coatings are discussed in the light of the chemistry that takes place at the interfaces. Copyright © 2004 Society of Chemical Industry     

F2.4微孔膜的制备及在膜蒸馏过程中应用的初步研究

采用相转化法制备了F2 4的疏水微孔膜 ,并对F2 4和PVDF微孔膜的机械性能以及疏水性等方面进行了对比 .结果表明 ,F2 4微孔膜在拉伸时的应变以及断裂伸长率约为PVDF微孔膜的 6～ 9倍 ;其接触角 (77 4°)也大于PVDF膜的接触角 (6 6 7°) .尽管膜蒸馏的数据显示F2 4微孔膜的蒸馏通量尚不及PVDF膜 ,但通过调节各项制膜参数 ,F2 4可能具有良好的应用前景     

防水粉憎水膜形成机理及稳定性的研究

通过对防水粉憎水膜形成途径的探索，提出了憎水膜形成过程的基本假设，利用微观测试方法证实了憎水膜层的存在．试验并研究了防水粉长期稳定性的诸多问题。     

Dyestuff—fibre interactions

The strength and nature of dye–fibre interactions vary according to fibre type and dye type. In the case of acid dyes for polyamide fibres, cationic dyes for acrylic fibres, disperse dyes for hydrophobic fibres, and direct dyes for cellulosic fibres, these interactions may be classified as non-covalent, a classification which includes van der Waals (VDW), electrostatic, induction, solvophobic and charge-transfer interactions.
Reactive dyes are a notable exception to the above, since the interaction which is responsible for their excellent wet fastness is the dye–fibre covalent bond, however, these dyes are increasingly viewed as environmentally unfriendly due to high salt usage and residual unfixed colour. This situation may be improved by either incorporating amine sites in the cellulose or by reversing the system to incorporate reactive residues in the fibre and nucleophilic sites in the dye.
Nonionic disperse dyes are valuable for hydrophobic fibres such as polyester but have made little impact on hydrophilic fibres such as silk, wool and cotton. Experiments to develop simple treatments to render the latter fibres disperse dyeable are described and the combined role of solvophobic and – interactions discussed.