塗料の保水性が塗工紙物性に与える効果（第１報） 塗工適性に対する塗料の保水性の影響

Water retentivity of allophane–titania nanocomposite films

This study presented a sustainable methodology for designing collagen-based biomaterials by using natural reinforcing agents and environmentally friendly cross-linking to improve water absorption, water retention and thermal stability − key features for biomedical and environmental applications. Collagen films were enhanced with keratin and natural polysaccharides (carboxymethyl cellulose, microcrystalline cellulose, acacia gum, soy protein, and carrageenan), then cross-linked by Vitex agnus-castus (VAC) extract as an eco-friendly alternative for synthetic cross-linkers. Glutaraldehyde was used for comparative analysis. A series of comprehensive analyses were conducted, including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and water absorption testing. Among all compositions, films containing 30% acacia gum and 3% VAC demonstrated the highest water absorption and retention capacity (5.90 g/g after 48 h) and enhanced thermal stability, with the minimal weight loss observed at 600 °C. FTIR analysis confirmed enhanced molecular connections through cross-linking, while DSC results validated increased structural resilience. The results indicated that VAC serves as both a structural and functional cross-linker, facilitating the creation of biodegradable, thermally resilient, and moisture-retentive films. This natural system presents significant potential for wound dressing and other biomedical applications within a sustainable material framework.

Comparison tests for plasma viscosity measurements

Poly(aryl ether ketone)/sulfated poly(vinyl alcohol) (S-SPAEK/SPVA) composite membranes with different mass fractions of SPVA were prepared by solution casting using highly sulfonated side-chain-type sulfonated poly(aryl ether ketone) and sulfated poly(vinyl alcohol) as raw materials. Fourier transform infrared (FTIR) spectroscopy confirmed the structure of the S-SPAEK/SPVA composite membranes. Scanning electron microscope (SEM) images showed that SPVA was uniformly dispersed in an S-SPAEK polymer matrix. The uptake and swelling behavior, water retention capacity, methanol permeability, and proton conductivity of the composite membrane were investigated systematically. The performance testing of the composite membranes revealed that thermal stability and water absorption and retention capabilities were improved by introduction of SPVA. The methanol permeability of S-SPAEK/SPVA composite membranes decreased as the content of SPVA increased because the hydroxyl groups could effectively obstruct diffusion of methanol molecules. The methanol diffusion coefficients of the composite membranes decreased from 7.9 x 10(-7) cm(2) . s(-1) for S-SPAEK/SPVA5 to 1.3 x 10(-7) cm(2) . s(-1) for S-SPAEK/SPVA30; considerably lower than 11.5x10(-7) cm(2) . s(-1) for the pure S- SPAEK membrane. The water absorption and retention capabilities increased as the numbers of hydrophilic groups increased by introduction of SPVA. As a result, the proton conductivity of the composite membranes increased with increasing water absorption and retention capabilities according to the Vehicle and Grotthuss mechanisms. The flexible chain segment of SPVA interacted strongly with the pendant chain of S-SPAEK, aiding hydrophilic/hydrophobic separation, and improving the proton conductivity of the composite membranes. The proton conductivity of the S- SPAEK/SPVA30 composite membrane reached 0.071 and 0.095 S . cm(-1) at 25 and 80 degrees C, respectively. These results show that S-SPAEK/SPVA composite membranes are promising for application in direct methanol fuel cells.

While hydrogel-based flexible sensors find extensive applications in fields such as medicine and robotics, their performance can be hindered by the rapid evaporation of water, leading to diminished sensitivity and mechanical durability. Despite the exploration of some effective solutions, such as introducing organic solvents, electrolytes, and elastomer composites, these approaches still suffer from problems including diminished conductivity, interface misalignment, and insufficient protection under dynamic conditions. Inspired by cell membrane structures, we developed an adaptive lipid-integrated bilayer coating (ALIBC) to enhance water retention in hydrogel-based sensors. Lipid layers and long-chain amphiphilic molecules are used as compact coating and anchoring agents on the hydrogel surface, mimicking the roles of lipids and membrane proteins in cell membranes, while spare lipids from aggregates within hydrogels can migrate to the surface to combat dehydration under deformation. This lipid-integrated bilayer coating prevents the water evaporation of hydrogels at both static and dynamic states without affecting the inherent flexibility, conductivity, and no cytotoxicity. Hydrogel-based sensors with ALIBC exhibited significantly enhanced performance in conditions of body temperature, extensive deformation, and long-term dynamic sensing. This work presents a general approach for precisely controlling the water-retaining capacity of hydrogels and hydrogel-based sensors without compromising their intrinsic physical properties.

Analysis of interfacial phenomena of aqueous solutions of polyethylene oxide and polyethylene glycol flowing in hydrophilic and hydrophobic capillary viscometers

The purpose of this study was to explore the water retention mechanism of chicken claws by detecting the structural changes in collagen in boneless chicken claws under different expansion rates. Firstly, boneless chicken claw collagen with different expansion rates (0%, 10%, 20%, 30%, 40%, 50%) was extracted by the acid-enzyme complex method, and the changes in collagen were determined by scanning electron microscopy (SEM), ultraviolet spectroscopy (UV), Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), low-field nuclear magnetic resonance LF-NMR) and surface hydrophobicity to explore the mechanism that leads to changes in the water retention performance. The results of scanning electron microscopy showed that with the increase in the expansion rate, collagen molecules showed curling, shrinking, breaking and crosslinking, forming a loose and irregular pore-like denatured collagen structure. UV analysis showed that the maximum absorption wavelength of chicken claw collagen was blue shifted under different expansion rates, and the maximum absorption peak intensity increased first and then decreased with the increase in expansion rate. The FTIR results showed that collagen had obvious characteristic absorption peaks in the amide A, B, I, II and III regions under different expansion rates, and that the intensity and position of the characteristic absorption peaks changed with the expansion rate. The results of the CD analysis showed that collagen at different expansion rates had obvious positive absorption peaks at 222 nm, and that the position of negative absorption peaks was red shifted with the increase in expansion rate. This shows that the expansion treatment makes the collagen of chicken claw partially denatured, and that the triple helix structure becomes relaxed or unwound, which provides more space for the combination of water molecules, thus enhancing the water absorption capacity of boneless chicken claw. The results of the surface hydrophobicity test showed that the surface hydrophobicity of boneless chicken claw collagen increased with the increase in expansion rate and reached the maximum at a 30% expansion rate, and then decreased with the further increase in the expansion rate. The results of LF-NMR showed that the water content of boneless chicken claws increased significantly after the expansion treatment, and that the water retention performance of chicken claws was further enhanced with the increase in the expansion rate. In this study, boneless chicken claws were used as raw materials, and the expansion process of boneless chicken claws was optimized by acid combined with a water-retaining agent, which improved the expansion rate of boneless chicken claws and the quality of boneless chicken claws. The effects of the swelling degree on the collagen structure, water absorption and water retention properties of boneless chicken claws were revealed by structural characterization. These findings explain the changes in the water retention of boneless chicken claws after expansion. By optimizing the expansion treatment process, the water retention performance and market added value of chicken feet products can be significantly improved, which is of great economic significance.

Probabilistic structural analysis of a Space Shuttle main engine turbopump blade is conducted using the computer code NESSUS (numerical evaluation of stochastic structures under stress). The goal of the analysis is to derive probabilistic characteristics of blade response given probabilistic descriptions of uncertainties in blade geometry, material properties, and temperature and pressure distributions. Probability densities are derived for critical blade responses. Risk assessment and failure life analysis is conducted assuming different failure models.

To alleviate soil impoverishment and water shortage in desert areas, as well as to reduce the impact of waste cabbage on the environment and human health, we used waste cabbage as a substrate, 2-acrylamide-2-methyl-1-propane sulfonic acid (AMPS) and acrylic acid (AA) as polymerization units, and NH4Cl and KNO3 as nutriment to obtain two waste cabbage-superabsorbent polymers (CB-SAPNH4Cl and CB-SAPKNO3) by the one-pot method. The chemical structure, thermal stability, and morphology of the polymers were investigated by Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and scanning electron microscope (SEM). Meanwhile, the water retention, water absorption, and salt resistance were compared with the purchased polymers. The results showed that the nutriment was successfully encapsulated inside the polymer, and CB-SAPNH4Cl and CB-SAPKNO3 at 1% nutrient concentration showed excellent water retention properties, salt resistance, and water absorption performance of 1546 and 1131 g/g (distilled water), 306 and 277 g/g (tap water), and 116 and 91 g/g (0.9% NaCl solution). Therefore, they are highly promising materials for the application.

This paper describes the synthesis of highretention water absorbents from kraft pulp and examination of their properties. A bleached kraft pulp from mixed hardwoods (LBKP) was carboxymethylated, then crosslinked with polyethylene glycol diglycidyl ethers (PEGDGE) with different degrees of polymerization under different conditions. A crosslinking agent with longer chain length might be advantageous for preparing a water absorbent with high water retention, and water retention could be improved at lower molar ratio of the crosslinking agent to the glucose unit. Isolation of carboxymethylated LBKP before crosslinking was advantageous for higher water absorbence. A water absorbent with a water retention value of as high as 500 times its weight was obtained.

Using corn straw as raw material, the water solution polymerization method was used to synthesize water absorption resin, and analyzed the initiator potassium persulfate dosage, crosslinking agent N-hydroxymethyl acrylamide (MBA) dosage, straw and acrylic acid mass ratio, and temperature of four factors, selected three influential factors for an orthogonal test. The results showed that the optimum single factor preparation conditions were as follows: the mass ratio of acrylic acid to corn stalk was 5, the mass ratio of acrylic acid to acrylamide was 5, the crosslinking agent was 1.0%, the initiator was 1.0%, the reaction temperature was 70°C, the water absorption rate was 17.232 g·g−1 and the water retention rate was 90.96%. The optimum preparation conditions were as follows: mass ratio of acrylic acid to straw was 5, initiator dosage ratio was 1.5%, and the reaction temperature was 70°C. Under these conditions, water absorption was 18.844 g·g−1 and water retention was 97.73%, indicating that the resin had good water absorption and water retention.

Effect of plates coating on performance of an indirect evaporative cooling system

Physically-based model of soil hydraulic properties accounting for variable contact angle and its effect on hysteresis

Research and application on the characteristics of compound cold water soluble gel in petrifilm aerobic count plates

The performance of hydrogels prepared with traditional natural starch as raw materials is considerable; the fixed ratio of amylose/amylopectin significantly limits the improvement of hydrogel structure and performance. In this paper, starch hydrogels were prepared by physical blending and chemical grafting, with the aid of ultrasonic heating. The effects of different amylose/amylopectin ratios on the microstructure and water retention properties of starch hydrogels were studied. The results show that an increase in amylopectin content is beneficial to improve the grafting ratio of acrylamide (AM). The interaction between the AM grafted on amylopectin and amylose molecules through hydrogen bonding increases the pores of the gel network and thins the pore walls. When the amylopectin content was 70%, the water absorption (swelling 45.25 times) and water retention performance (16 days water retention rate 44.17%) were optimal. This study provides new insights into the preparation of starch-based hydrogels with excellent physical and chemical properties.