Excellent Water Absorption Research Articles

Bletilla striata polysaccharide modified collagen fiber composite sponge with rapid hemostasis function

Emergencies often result in uncontrollable bleeding, which is thought to be the leading cause of death at the scene of the injured. Among various hemostasis scenarios, collagen fiber (CF) is gradually replacing traditional hemostatic materials due to its superior properties and ease of sourcing from animals. Herein, we use CF and the natural herbaceous Bletilla striata as raw materials to prepare a collagen fiber-oxidized Bletilla striata composite hemostatic sponge (CFOB). During the cross-linking process, the triple helix structure of collagen stays intact, and its porous three-dimensional network structure brings excellent bulkiness and water absorption properties. Experiments show that the optimal amount of sponge CFOB-10, namely oxidized Bletilla striata polysaccharide 0.5 mg/mL and CF 5 mg/mL, only needed 25 ± 4.06 s for hemostasis time in the rat liver hemorrhage model. In addition, CFOB meets the safety performance requirements of cytotoxicity classification standard 0. Therefore, the optimal amount of CFOB is an excellent new hemostatic material with application potential.Graphical

Novel superabsorbent polymer composites based on α-cellulose and modified zeolite: synthesis, characterization, water absorbency and water retention capacity

Most superabsorbent polymers (SAPs) are prepared based on synthetic polymers (from petroleum resources), making them costly, nondegradable, and not ecofriendly. To overcome these drawbacks, biodegradable and renewable natural materials are proposed as additions into SAPs. In this article, a new SAP composite was synthesized by using AA, AM, α-cellulose, and modified zeolite (MZE). The prepared SAP composites were analysed by FTIR spectroscopy, XRD, SEM and TGA. Then, their water absorbency and water retention capacity results were evaluated. AA and AM were successfully grafted to the α-cellulose chains, and MZE was uniformly dispersed in the SAP composite matrix as an inorganic filler, which endowed the SAP composites with a more undulant and coarser surface along with more abundant hydrophilic groups. In contrast with poly(AA-co-AM), the water absorbency of the prepared SAP composites increased by 93.88% in distilled water and 89.58% in 0.9 wt.% NaCl solution. Additionally, the water retention time of these SAP composites was 11.2 h when evaluated at 50 °C, which was a 71.79% increase. Moreover, both the Tonset and Tpeak of the prepared SAP composites slightly increased compared with those of α-cellulose-poly(AA-co-AM), showing that the introduction of MZE could slightly improve the thermal stability of the SAP composites. These novel SAP composites with their excellent water absorbency and retention capacity could be applied to the agricultural and horticultural fields as water-keeping materials.

A multifunctional 3D dressing unit based on the core-shell hydrogel microfiber for diabetic foot wound healing.

The healing mechanism of diabetic foot wounds is very complicated, and it is difficult for a single-function medical dressing to achieve good therapeutic effects. We propose a simple coaxial biological 3D printing technology, which uses one-step 3D deposition to continuously produce multifunctional medical dressings on the basis of core-shell hydrogel fibers. These dressings have good biocompatibility, controlled drug-release performance, excellent water absorption and retention, and antibacterial and anti-inflammatory functions. In vivo experiments with type 2 diabetic rats were performed over a 14-day period to compare the performance of the multifunctional 3D dressing with a gauze control; the multifunctional 3D dressing reduced inflammation, effectively increased the post-healing thickness of granulation tissue, and promoted the formation of blood vessels, hair follicles, and highly oriented collagen fiber networks. Therefore, the proposed multifunctional dressing is expected to be suitable for clinical applications for healing diabetic foot wounds.

Effects of organification degree of mordenite on swelling behaviors of starch-g-poly (acrylic acid) /organo-mordenite superabsorbent composites

Starch-g-poly(acrylic acid)/organo-mordenite (St-g-PAA/OMOR) superabsorbent composites were prepared via inverse suspension polymerizationutilizing potassium persulfate as an initiator and N, N’-methylene bisacrylamide as a crosslinker. Different dosages of cetyltrimethylammonium bromide were used to obtain organo-mordenite (OMOR) samples with different organification degrees. The effects of the organification degree of OMOR on the water absorbency, swelling behavior, and reswelling properties of St-g-PAA/OMOR were studied. The results from both FTIR and XRD analyses indicate that the Si–OH group of OMOR was involved in the formation of the St-g-PAA/OMOR composite. SEM analyses showed that the organification degree of OMOR influenced the morphology of the St-g-PAA/OMOR composite. The water absorption absorbency, swelling rate, and reswelling capability of the St-g-PAA/OMOR composite prepared using the OMOR with the optimal organification degree were superior to those of the St-g-PAA/mordenite composite. The swelling behaviors of the St-g-PAA/OMOR composites, which were measured in distilled water, obeyed Schott’s second-order kinetics model. The St-g-PAA/OMOR composite prepared using the OMOR with the 8 wt.% organification degree had the highest water absorption capacity and the highest swelling rate. Moreover, after five swelling–shrinking cycles, the composite retained its excellent water absorption capacity.

A novel multifunctional fertilizer derived from wasted straw: Synthesis, characteristics and agriculture applications

In order to enhance utilization of millet straw and reduce fertilizer loss, a novel multifunctional fertilizer (MS-g-PAA/PDMUA) was developed using straw cellulose and linear polymer (PDMUA) by semi-interpenetrating technology. The structure and morphology characterization of MS-g-PAA/PDMUA were measured by fourier-transform infrared, x-ray diffraction, x-photoelectron spectroscopy and scanning electron microscopy techniques, to provide evidence of semi-IPNs networks and component interactions, and the results show that the product exhibited excellent water absorbency (562.3 g/g) and enhanced the soil infiltration. Cumulative release of N, P was 49.2% and 55.1%, respectively, after 40 days, coming up to the Committee of European Normalization (CEN) standard. The agricultural application of MS-g-PAA/PDMUA showed that it could promote growth indexes of wheat, which could improve wheat yields. Therefore, desirable water retention, slow-release properties, and wheat growth effects highlight the product’s potential for agriculture application.

Enhancement of water absorption capacity and compressibility of hydrogel sponges prepared from gelatin/chitosan matrix with different polyols

The hydrogel sponges have prepared successfully from gelatin/chitosan (GEL/CTS) matrix with different polyols basing on scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analysis. The results indicate that the compressibility and thermal properties (thermal gravimetric analysis, TGA) were improved significantly with adding the different polyols [poly(vinyl alcohol) – PVA, and poly(ethylene glycol)-poly(propylene glycol)- poly(ethylene glycol) – PEPEG] into GEL/CTS matrix. Specially, the as-prepared hydrogel sponges with superabsorbent behavior were also investigated with the attained water absorption capacity to 605 ​g ​g−1 and 585 ​g ​g−1 for GCV_1/1/0.3 and GCE_1/1/0.3 sponges, respectively, as well as the excellent water absorption capacity in a wide range of pH and salt concentration. Hence, these studies demonstrated that the hydrogel sponges are concerned as potential and promising candidates to apply especially in the fields of biomedicine and hygiene.

White Cabbage (Brassica oleracea L.) waste, as biowaste for the preparation of novel superabsorbent polymer gel

In order to reduce the pollution of the bio-waste cabbage to the environment and achieve recycling of biological waste resources, synthesis of a novel superabsorbent polymer gel based on waste cabbage (CB) using two monomers AMPS (2-acrylamide-2-methyl-1-propane sulfonic acid) and AA (acrylic acid). And the synthesis conditions were optimized, such as the ratio of AMPS and AA, initiator content, and crosslinker content. And the water retention, salt resistance and repeated swelling performance were investigated too. The chemical structure thermal stability and microscopic appearance of the superabsorbent polymer gel were investigated by Fourier transform infrared spectroscopy (FTIR), Thermal gravimetric analysis (TGA) and Scanning electron microscope (SEM). The results showed that the novel superabsorbent polymer gel exhibits excellent water absorbency, which can absorb ultrapure water, distilled water, tap water and 0.9% NaCl solution are 1914 g/g, 1726 g/g, 306 g/g and 114 g/g, respectively. This is higher than in related studies 30%− 40% in distilled water, 60%− 70% in tap water and 10%− 20% in 0.9% NaCl solution. Therefore, this superabsorbent polymer gel showed a high swelling property and stable salt resistance. It has a broad application prospect.

Bionanocellulose/Poly(Vinyl Alcohol) Composites Produced by In-Situ Method and Ex-Situ/Impregnation or Sterilization Methods.

The purpose of the work was to obtain composites based on bionanocellulose (BNC) and poly(vinyl alcohol) (PVA) for specific biomedical and cosmetic applications and to determine how the method and conditions of their preparation affect their utility properties. Three different ways of manufacturing these composites (in-situ method and ex-situ methods combined with sterilization or impregnation) were presented. The structure and morphology of BNC/PVA composites were studied by ATR-FTIR spectroscopy and scanning microscopy (SEM, AFM). Surface properties were tested by contact angle measurements. The degree of crystallinity of the BNC fibrils was determined by means of the XRD method. The mechanical properties of the BNC/PVA films were examined using tensile tests and via the determination of their bursting strength. The water uptake of the obtained materials was determined through the gravimetric method. The results showed that PVA added to the nutrient medium caused an increase in biosynthesis yield. Moreover, an increase in base weight was observed in composites of all types due to the presence of PVA. The ex-situ composites revealed excellent water absorption capacity. The in-situ composites appeared to be the most durable and elastic materials.

An extrusion granulation process without sintering for the preparation of aggregates from wet dredged sediment

In order to avoid the energy consumption of dewatering and dust pollution in the preparation of non-sintered lightweight aggregates from dredged sediment, a new low-dust process of preparing non-sintered extruded wrap-shell aggregates (TH-WSLAs-W) by extrusion granulation is proposed and applied to produce TH-WSLAs-W baking-free bricks (TH-WSLAB-W). The basic physical properties (cylinder compressive strength, bulk density and water absorption) and microstructure of TH-WSLAs-W was explored. It shows that the curing agent will form a hydrophobic gel film around the sediment particles and form a network structure, which enhances the cylinder compressive strength (6.7 MPa) and frost resistance of TH-WSLAs-W. In addition, the interfacial transition zone among TH-WSLAB-Ws was studied by scanning electron microscope. It found that the micropore structure endow the TH-WSLAs-W with excellent water absorption and drainage property, promoting the hydration of cement, promising the integration of aggregate and cement, and its compressive strength reaches 20.5 MPa.

Optimization of N,N’-methylenebis(acrylamide), and ammonium persulfate content in carbonaceous/acrylic acid-co-acrylamide superabsorbent polymer

Carbon filler addition in the superabsorbent polymers (SAP) network shows excellent water absorption capability. However, other than filler, the water absorbency was also influenced by crosslinker, initiator, and monomer contents during the SAP synthesis. This work aimed to optimize the amount of N,N’-methylenebisacrylamide (NNMBA) as a crosslinker, and ammonium persulfate (APS) as initiator using Response Surface Methodology (RSM) for carbonaceous/acrylic acid-co-acrylamide based SAP (C-SAP) synthesis. Inverse suspension polymerization was used for the C-SAP synthesis with a fixed amount of acrylic acid, acrylamide, and carbonaceous filler at 70 °C for 3 h. The characteristics of the C-SAP were further analyzed using the tea bag method, FTIR, and FESEM. The highest water absorbency recorded is 453.11 g/g at 0.006 wt% APS and 0.0009 wt% NNMBA with R2 of 0.9077, which is low content of crosslinker and initiator. Overall, optimum crosslinker and initiator are important parameters that increase the prospect of C- SAP, particularly in agricultural applications.

Effect of highly efficient substrate modifier, super-absorbent polymer, on the performance of the green roof

Green roofs are commonly used in sponge city construction. However, the limitations of substrate thickness and strong sunlight have caused water retention to become the primary problem in the promotion of this technology. Super-absorbent polymer (SAP) is a material with excellent water absorption capacity that is expected to improve the substrate to solve the problem of the insufficient water storage capacity of green roofs. In this study, the basic performances of two types of SAPs, namely polyacrylate sylvite and acrylic acid-attapulgite hybrid (P-SAP and A-SAP, respectively), were evaluated on a bench-scale. The results showed that both SAPs had good water absorption, reusability, and fertilizer protection ability. These SAPs could maintain high water absorption within a certain range of salinity, pH, and temperature. Although water absorption of P-SAP was higher than that of A-SAP, the latter showed a significant advantage in substrate modification. After adding A-SAP (application rate: 0.6%, particle size: 12 mesh), the water storage capacity of the substrate was significantly improved, with an increase in the saturation moisture content of 23.8% and a decrease in the infiltration rate of 48.5%. A simulator of green roof was constructed with A-SAP under optimal conditions. The enhancement of the water retention capacity increased the drought resistance of the plants, which improved their growth; in particular, the fresh weight was 98% higher than that of the control group. A-SAP increased the rate of building up the lawn by 25%. The average soil moisture of the A-SAP group was 63.3%, which was 10.0% higher than that of the control group. An increase of more than 26% in the runoff control capacity was found in the green roof with A-SAP. Overall, our study indicates that A-SAP is a practical and efficient modifier for green roofs.

Biomimetic three-layered membranes comprising (poly)-ε-caprolactone, collagen and mineralized collagen for guided bone regeneration.

The distinct structural properties and osteogenic capacity are important aspects to be taken into account when developing guided bone regeneration membranes. Herein, inspired by the structure and function of natural periosteum, we designed and fabricated using electrospinning a fibrous membrane comprising (poly)--ε-caprolactone (PCL), collagen-I (Col) and mineralized Col (MC). The three-layer membranes, having PCL as the outer layer, PCL/Col as the middle layer and PCL/Col/MC in different ratios (5/2.5/2.5 (PCM-1); 3.3/3.3/3.3 (PCM-2); 4/4/4 (PCM-3) (%, w/w/w)) as the inner layer, were produced. The physiochemical properties of the different layers were investigated and a good integration between the layers was observed. The three-layered membranes showed tensile properties in the range of those of natural periosteum. Moreover, the membranes exhibited excellent water absorption capability without changes of the thickness. In vitro experiments showed that the inner layer of the membranes supported attachment, proliferation, ingrowth and osteogenic differentiation of human bone marrow-derived stromal cells. In particular cells cultured on PCM-2 exhibited a significantly higher expression of osteogenesis-related proteins. The three-layered membranes successfully supported new bone formation inside a critical-size cranial defect in rats, with PCM-3 being the most efficient. The membranes developed here are promising candidates for guided bone regeneration applications.

Modelling of basic blue-9 dye sorption onto hydrolyzed polyacrylonitrile grafted starch composite

This study reports the synthesis of a superabsorbent hydrogel (HS) through the polyacrylonitrile (PAN) graft copolymerization and subsequent hydrolysis of corn starch. The surface morphology and chemistry, as well as the physicochemical characteristics of the hydrogel, were elucidated. The effectiveness of the synthesized hydrogel sorbent for remediating a basic blue-9 dye contaminated stream was subsequently investigated. Also, the relationship between the different process variables and the hydrogels’ remediation (sorption) capacity was studied, while the generated experimental kinetic and equilibrium data were effectively modelled using relevant isotherm and kinetic models. The Langmuir isotherm and pseudo-first-order kinetic models fitted best to the equilibrium and kinetic data, respectively. By applying specified mechanistic models, the intraparticle diffusion mechanism was identified as the sole rate-limiting step of the sorption process. The hydrogel showed excellent water absorption and monolayer sorption capacities of 710 ±1.6 g water/g and 343.27 ±1.3 mg/g, respectively. Thus, the hydrogel shows potential for the decontamination of dyestuff polluted streams.

Design of acrylic acid/nanoclay grafted polysaccharide hydrogels as superabsorbent for controlled release of chlorpyrifos

In the present study, acrylic-bonded starch nanocomposite hydrogels were synthesized in the presence of montmorillonite nanoclay. N,N′-methylenebisacrylamide was used as a crosslinker and ammonium persulfate was used as an initiator. The hydrogel performance was investigated as superabsorbent for water absorption under different synthesis conditions such as acrylic acid to starch ratio, crosslinker, initiator, and nanoclay amounts, and pH. Synthetic nanocomposites were characterized and approved using FTIR, XRD, FESEM-EDX, and DTA techniques. Under optimal conditions (acrylic acid to the starch ratio: 7 to 1, potassium persulfate: 0.04 g, methylenebisacrylamide: 0.002 g, nanoclay: 1 g, and pH = 7), the swelling ratio of synthetic hydrogel reached up to 400 times of the gel strength of the matrix. This superabsorbent was then investigated as a carrier for the controlled release of chlorpyrifos after in situ loading in different concentrations. The hydrogel with 1.0 M chlorpyrifos content showed a release percentage of 85% after 14 days. This proposed nanocomposite with excellent water absorbency, controlled release of chlorpyrifos, the economical and environment-friendly structure can be useful in agricultural applications.

Potential of preparing meat analogue by functional dry and wet pea (Pisum sativum) protein isolate

The process of replacing animal proteins with plant-based proteins is still faced with the uncertain structural and processing properties of the isolated plant proteins. This study evaluated pea proteins obtained by dry (air classification combined with electromagnetic separation) and wet (isoelectric point precipitation) separation at the process-function-product level. The results showed that there was a significant difference in the purity of the isolated pea proteins obtained by dry (72.3 ± 0.7 g/100 g) and wet (89.2 ± 0.5 g/100 g) separation. High performance liquid chromatography, SDS gel electrophoresis and fluorescence analysis techniques showed that the dry-separated proteins maintained their native structure and presented excellent solubility and water absorption property, which lead to a porous and soft meat analogue. Although the wet separation resulted in denaturation of the protein, the essential amino acids contents were closer to the recommended level. Due to its higher purity, wet-separated proteins had better emulsification and foaming properties, and the resulting dough was more solid-like with higher hardness than dry-separated proteins. This study allowed a deeper understanding of pea proteins obtained by dry and wet separation and their potential use in the development of meat analogues.

From the Waste Semicoke to Superabsorbent Composite: Synthesis, Characterization and Performance Evaluation

Oil shale semicoke (SC), which generated during the production of shale oil has attracted much attention in agriculture recently, as the composition of organic matter, clay mineral and else. In this study, a novel superabsorbent composite of poly(acrylic acid-co-acrylamide)/semicoke (P(AA-co-AM)/SC) was prepared by polymerization of the acrylic acid (AA) and acrylamide (AM) via a convenient one-step reaction as the presence of SC. The characterization of FTIR, SEM, XPS and TG indicated that the successful polymerization and the SC had participated into the construction of 3D polymeric network in superabsorbent. The performance testing results showed that the superabsorbent composites exhibited the excellent water absorbency, favorable water retention properties, fast swelling rate, and nice water reusability. And a 10% of SC amount could improve the water absorbency to 643.13 g/g and 79.82 g/g in distilled water and 0.9% NaCl solution, respectively. The potted culture experiments revealed that the increased water retaining capacity of soil and obvious growth promoting effect for crop. In a word, the novel superabsorbent composite could be as a potential water-saving product used in the agriculture, and the approach reported in this work also can be as a new pathway for high value using of SC via a sustainable chemical engineering process.

Preparation of nano-hydroxyapatite/chitosan/tilapia skin peptides hydrogels and its burn wound treatment

There is an urgent need for wound dressings to treat partial-thickness burns. Hydrogels are a promising material that can maintain hydration to promote necrotic tissue removal. Tilapia peptides (TP) and hydroxyapatite (HA) were incorporated into chitosan system to prepare new types of hydrogels. The hydrogels were cross-linking by tannin (TA), which were developed to promote rapid wound healing in a New Zealand rabbit partial-thickness burn model. Nanohydroxyapatite (NHA) was synthesized by coprecipitation method, which made hydrogels have a highly porous structure comprised of interconnected pores, excellent water absorption and low hemolysis. Besides, the hydrogels showed excellent antimicrobial activities against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), as well as the cytocompatibility on endothelial cells. Moreover, the hydrogels promoted epithelial and dermal regeneration, reduce the expression of TNF-α and IL-6 and promote the skin regeneration by enhancing expression of collagen, STAT3, and VEGF.

Unidirectional Water-Transport Antibacterial Trilayered Nanofiber-Based Wound Dressings Induced by Hydrophilic-Hydrophobic Gradient and Self-Pumping Effects

Excessive wound exudates often cause infection and hinder wound repair and regeneration. It is therefore urgently needed to develop an ideal wound dressing for pumping the excessive biofluids and inhibiting bacterial infection in the wound healing process. Herein, we demonstrate a facile and efficient strategy to fabricate the unidirectional water-transport antibacterial wound dressings by embedding macromolecular antimicrobials into a multilayer nanofibrous membrane featured with hydrophobic-to-hydrophilic gradient structure and self-pumping effect using an electrospinning technique. Thanks to these features, the obtained nanofibrous dressings achieved excellent unidirectional water-transport performance, which could drive wound exudates to flow spontaneously from inside to outside and prevent pumped biofluids rewetting the wounds. In addition, the designed trilayered dressing exhibited approximately 100% antibacterial ability against Staphylococcus aureus and Escherichia coli when the concentration of antibacterial agents polyhexamethylene guanidine hydrochloride (PHGC) was 0.06 wt%. Moreover, the trilayered dressings revealed excellent water absorption performance, air and moisture permeability, mechanical strength, biocompatibility, and low cell adhesion behavior, indicating the potential applications for the trilayered nanofibrous wound dressings in wound care.

Superabsorbent hydrogels enhanced by quaternized tunicate cellulose nanocrystals with adjustable strength and swelling ratio

Superabsorbent hydrogels were prepared from biodegradable material, where the matrix was cross-linked cellulose and carboxymethyl cellulose and reinforced by quaternized tunicate cellulose nanocrystals (Q-TCNCs). Due to the large amount of hydrophilic groups on cellulose, carboxymethyl cellulose, and Q-TCNCs, the hydrogels had excellent water absorption capacity. The equilibrium swelling ratio of superabsorbent hydrogels exceeded 500 g/g in deionized water and exceeded 120 g/g even in synthetic urine, which was higher than those of commercial absorbent materials composed of copolymers of acrylic acid and acrylamide. The water absorption performances and mechanical properties of the hydrogels could be adjusted by changing the content of Q-TCNCs. The resultant materials were expected to replace those polyolefin-based materials, thereby reducing environmental pollution.

Bottom‐Up Ecofriendly Strategy for Construction of Sustainable Bacterial Cellulose Bioaerogel with Multifunctional Properties

AbstractThe production of sustainable bioaerogel by using renewable biomass via eco‐friendly techniques is a meaningful research topic. This study reports a facile bottom‐up green strategy to construct dimensionally stable bioaerogel derived from bacterial cellulose (BC). Taking advantages of the natural hierarchical and interconnected network structure of BC, the preparation of bioaerogel comprises directional freezing, followed by freeze‐drying approach. Aside from the multifunctional characteristics such as high porosity, low density, and large specific surface area, the resultant BC bioaerogels show superhydrophilic property, excellent water absorption, and swelling characteristics. In addition, the extremely compressed bioaerogel film exhibits flexibility and good mechanical properties. And the BC bioaerogels display a low coefficient of thermal conductivity (25.8 mW m−1 K−1). Moreover, the BC bioaerogels reveal excellent sound absorption at board frequencies from 200 to 6000 Hz with a maximum sound‐absorption coefficient of 0.97. The BC bioaerogel is further used as the green, sustainable, and degradable cigarette filter tip, exhibiting good adsorption effect for the smoke main components. In summary, this study provides a feasible solution to rationally construct lightweight, high porous, heat‐insulating, and highly efficient sound‐adsorption BC bioaerogel, which has potential applications in the future as green advanced functional materials.