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

Cellulose ◽  
2021 ◽  
Author(s):  
Peng Wei ◽  
Weiwei Chen ◽  
Qinghua Song ◽  
Yibing Wu ◽  
Youjia Xu
Keyword(s):  
Water Absorption ◽  
Cellulose Nanocrystals ◽  
Carboxymethyl Cellulose ◽  
Absorption Capacity ◽  
Swelling Ratio ◽  
Biodegradable Material ◽  
Equilibrium Swelling ◽  
The Matrix ◽  
Equilibrium Swelling Ratio ◽  
Superabsorbent Hydrogels

AbstractSuperabsorbent 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.

Preparation of pH Sensitive Polyacrylic Acid(PAAc) Macroporous Hydrogels in Aqueous NaCl Solutions and their Characterization

2009 ◽  
Vol 79-82 ◽  
pp. 1999-2002
Author(s):  
Yu Hua Xue ◽  
Wen Yuan Zhao ◽  
Shou Feng Sun ◽  
Hu Yu
Keyword(s):  
Polyacrylic Acid ◽  
Response Rates ◽  
Ph Sensitive ◽  
Swelling Ratio ◽  
Ph Changes ◽  
Nacl Concentration ◽  
Equilibrium Swelling ◽  
Swelling Studies ◽  
Equilibrium Swelling Ratio

In this study, macroporous, pH sensitive polyacrylic acid hydrogels were prepared by using different concentration of aqueous NaCl solutions as the polymerization medium. The optical photos showed that the pore morphologies of the hydrogels were dependent on the concentration of NaCl. Swelling studies showed an increase in equilibrium swelling ratio as the NaCl concentration in the polymerization medium increased from 0 to 0.7mol/L. The hydrogels exhibited stronger sensitivity to pH changes, and showed much faster reswelling and deswelling response rates with the NaCl concentration increasing in the polymerization medium.

Bio-nanocomposites based on compatibilized poly(lactic acid) blend-reinforced agave cellulose nanocrystals

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5538-5555
Author(s):  
Noor Afizah Rosli ◽  
Wan Hafizi Wan Ishak ◽  
Siti Salwani Darwis ◽  
Ishak Ahmad ◽  
Mohammad Fauzul Azim Mohd Khairudin
Keyword(s):  
Lactic Acid ◽  
Water Absorption ◽  
Cellulose Nanocrystals ◽  
Tensile Modulus ◽  
Crystallization Rate ◽  
Tensile Tests ◽  
Absorption Capacity ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Green Materials

Enhancing the mechanical, thermal, and degradation properties of a poly(lactic acid) (PLA) blend without deteriorating its other useful features was the goal of this work. The isolation of cellulose nanocrystals (CNCs) from Agave angustifolia fibers was carried out, and the properties of the bio-nanocomposites comprising these CNCs were evaluated, which included PLA, natural rubber (NR), and liquid NR (LNR). Transmission electron microscopy and zeta potential analysis confirmed the successful isolation of CNCs from agave fibers after several chemical treatment steps. The effects of different CNC loadings on the properties of the bio-nanocomposites were investigated using tensile tests, thermal analysis, morphological analysis, and water absorption tests. Bio-nanocomposites containing 5 wt% and 7.5 wt% CNC had the optimal tensile modulus and strength, respectively. Different levels of CNC did not noticeably affect the thermal stability of the bio-nanocomposites, although the thermogram curves increased slightly as CNC content increased. The addition of CNC at different loadings affects the crystallization rate of PLA blend. The water absorption capacity increased as CNC level increased, and 5 wt% CNC gave rise to the highest water absorption. The four-component bio-nanocomposites created in this study provided an alternative for producing new green materials with tunable physical, mechanical, and thermal properties.

Studies on Surface Hydroxypropylation and Swellability of Bacterial Cellulose

2012 ◽  
Vol 601 ◽  
pp. 12-15 ◽  
Author(s):  
Tong Wan ◽  
Li Ying Liu ◽  
Wei Zeng ◽  
Yong Zhu
Keyword(s):  
Surface Modification ◽  
Sodium Hydroxide ◽  
Bacterial Cellulose ◽  
Propylene Oxide ◽  
Acetobacter Xylinum ◽  
Swelling Ratio ◽  
Freeze Dried ◽  
Equilibrium Swelling ◽  
Equilibrium Swelling Ratio

Bacterial Cellulose (BC) consisting of hydrophobic ultra-fine fibers was produced by Acetobacter xylinum. Hydroxypropyl bacterial celluloses (HPBC) were synthesized by surface modification of nano-fibrils via hydroxypropylation using two modifier systems, sodium hydroxide/ propylene oxide as system (I) and sodium hydroxide/urea/propylene oxide as system (II) respectively. The equilibrium swelling ratio (ESR) of HPBC was studied. ESR of HPBC obtained from system (I) was significantly higher than that obtained from system (II). The maximum ESR of HPBC was nearly 70 times larger than that of air dried BC and 10 times larger than that of freeze dried BC.

scholarly journals Preformed particle gel: evaluation and optimization of salinity and pH on equilibrium swelling ratio

2012 ◽  
Vol 2 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Asefe Mousavi Moghadam ◽  
Mohsen Vafaie Sefti ◽  
Mahsa Baghban Salehi ◽  
Ahmad Dadvand Koohi
Keyword(s):  
Swelling Ratio ◽  
Preformed Particle Gel ◽  
Equilibrium Swelling ◽  
Equilibrium Swelling Ratio

Characterization of cellulose nanocrystals extracted from El Diss and El Retma local plants and their dispersion in poly(vinyl alcohol-co-ethylene) matrix in the presence of borax

2020 ◽  
pp. 096739112091087
Author(s):  
Lilia Benchikh ◽  
Abdelhafid Merzouki ◽  
Yves Grohens ◽  
Melia Guessoum ◽  
Isabelle Pillin
Keyword(s):  
Water Absorption ◽  
North Africa ◽  
Cellulose Nanocrystals ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
The Matrix ◽  
Dsc Analyses ◽  
Local Plants

This study aims to investigate the potential of two local fibers, namely El Diss and El Retma, which are abundant in the mountains of North Africa (Sétif, Algeria), to provide cellulose nanocrystals (CNCs). Then, the isolated CNCs from El Diss were used as a reinforcement for a poly(vinyl alcohol-co-ethylene) matrix (EVOH) in the absence and in the presence of borax which was added to improve the interactions between the CNCs and the matrix. The extracted CNCs from both El Diss (CNCD) and El Retma (CNCR) were characterized by Zeta-sizer analysis using dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electronic microscopy. Also, untreated EVOH/CNCD nanocomposites and borax-treated EVOH/CNCD/BOR have been characterized using FTIR, differential scanning calorimetry (DSC) analyses, and by the study of their water absorption behavior. The DLS analysis provided the transversal length of the particles and showed that the surface of the obtained CNCs is negatively charged due to the presence of sulfated ions. Also, FTIR results confirmed the elimination of extra cellulosic substances, whereas TGA proved that the degradation of CNCs occurs at relatively lower temperatures compared with the neat fibers. The incorporation of borax to EVOH/CNCD nanocomposites showed its efficiency in improving the interactions at the interface between EVOH and the CNCD, which significantly affected the material’s thermal properties as concluded from DSC results and their water absorption behavior.

scholarly journals Synthesis and characterization of temperature-sensitive and biodegradable hydrogel based on N-isopropylacrylamide

2010 ◽  
Vol 8 (2) ◽  
pp. 426-433 ◽  
Author(s):  
Yueqin Yu ◽  
Yanshun Li ◽  
Chunjing Zhu ◽  
Lingxiu Liu
Keyword(s):  
Enzymatic Degradation ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Swelling Kinetics ◽  
Swelling Ratio ◽  
Nacl Solution ◽  
Equilibrium Swelling ◽  
Cross Linker ◽  
The Cross ◽  
Equilibrium Swelling Ratio

AbstractBased on a biodegradable cross-linker, N-maleyl chitosan (N-MACH), a series of Poly(N-isopropylacrylamide) (PNIPAAm) and Poly(N-isopropylacrylamide-co-acrylamide) [P(NIPAAm-co-Am)] hydrogels were prepared, and their lower critical solution temperature (LCST), swelling kinetics, equilibrium swelling ratio in NaCl solution, and enzymatic degradation behavior in simulated gastric fluids (SGF) were discussed. The LCST did not change with different cross-linker contents. By altering the NIPAAm/Am molar ratio of P(NIPAAm-co-Am) hydrogels, the LCST could be increased to 39°C. The LCST of the hydrogel was significantly influenced by the monomer ratio of the NIPAAm/Am but not by the cross-linker content. In the swelling kinetics, all the dry hydrogels exhibited fast swelling behavior, and the swelling ratios were influenced by the cross-linker content and NIPAAm/Am molar ratios. Equilibrium swelling ratio of all the hydrogels decreased with increasing NaCl solution concentration. In enzymatic degradation tests, the weight loss of hydrogels was dependent on the cross-linker contents and the enzyme concentration.

scholarly journals Materiale compozite pe baza de deseuri de beton celular autoclavizat si rasina poliesterica nesaturata

2019 ◽  
Vol 56 (1) ◽  
pp. 256-260
Author(s):  
Gelu Coman ◽  
Gabriel-Bogdan Carp ◽  
Ion Ion ◽  
Alina Ceoromila ◽  
Nicusor Baroiu
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Thermal Resistance ◽  
Water Absorption ◽  
Unsaturated Polyester ◽  
Absorption Capacity ◽  
Insulation Material ◽  
Water Absorption Capacity ◽  
The Matrix ◽  
Influence Of Water

This paper presents an experimental study on the potential use of new type of composite as insulation material. The composite material (AACW-UPR) was synthesised through mixture between the Autoclaved Aerated Concrete Waste (AACW) as filler and Unsaturated Polyester Resin (UPR) as matrix. Several samples of the composite material with different UPR concentrations (50 and 70 vol.%) and different AACW particle size (0.2-1 mm, 1.5-2.5 mm, 3-6 mm) were prepared. The thermal behaviour and the water absorption capacity of the AACW-UPR composite materials were studied. Also, the influence of water absorption capacity on thermal resistance and thermal conductivity was studied. During the investigations we noticed the following: good chemical compatibility between the AACW particles and the UPR matrix; a decrease in thermal conductivity for samples with 50 vol.% UPR and inserted particles size between 3-6 mm and an increase in water absorption capacity with the increase in the filler content in the matrix. The increasing water absorption capacity determined a decrease in thermal resistance and a reduction of the composite features as insulating material.

Effect of pH and temperature on swelling Behaviour of tamarind gum

2021 ◽  
pp. 5471-5474
Author(s):  
Braja B. Panda ◽  
Rudra N. Sahoo ◽  
Nilamadhab Nayak ◽  
Subrata Mallick
Keyword(s):  
Water Content ◽  
Gravimetric Method ◽  
Swelling Ratio ◽  
Effect Of Ph ◽  
Plant Polysaccharide ◽  
Solvent Uptake ◽  
Equilibrium Swelling ◽  
Ph Conditions ◽  
Solvent Molecules ◽  
Equilibrium Swelling Ratio

Natural gum tamarind is a plant polysaccharide extracted from seeds endosperm of the plant, Tamarindus indica Linn. Thin film of the gum was prepared by direct compression method. The prepared film was investigated for the effect of pH and temperature on solvent uptake property of film by gravimetric method. Different swelling parameters such as mass swelling ratio (MSR), equilibrium swelling ratio (ESR), equilibrium swelling ratio (ESw) and the equilibrium water content (EWC) were studied. It was found that swelling parameters were influenced by different pH and temperature conditions. The results suggested that the water content in equilibrium state was similar to body fluid. The gum converted to a high viscous gel of pseudo plastic characteristics in different pH conditions and the mechanism of continuous diffusion of solvent molecules into tablet during swelling was a non fickian and followed a second order kinetics.

Water-Swelling Rubber Containing Small Amount of Nanofillers with Enhanced Water Swelling Durability

2013 ◽  
Vol 774-776 ◽  
pp. 544-547
Author(s):  
Wei Han ◽  
You Hong Tang
Keyword(s):  
Room Temperature ◽  
Superabsorbent Polymer ◽  
Swelling Ratio ◽  
Loss Ratio ◽  
Degree Of Swelling ◽  
Equilibrium Swelling ◽  
Mechanical Behaviours ◽  
Equilibrium Swelling Ratio ◽  
Water Swelling ◽  
Weight Loss Ratio

A series of water-swelling rubbers (WSR) were prepared by directly mixing room temperature vulcanization-2 components silicone rubber (RTV-2 SR) with superabsorbent polymer (SAP) and nanofiller (s) (halloysite nanotube or/and CaCO3). The effects of component on its mechanical behaviours and water-absorbent properties such as degree of swelling, swelling ratio, and weight loss ratio were investigated. The equilibrium swelling ratio increased with increasing amounts of water-absorbent resin. Well-dispersed nanofiller (s) increased the mechanical properties of WSR and prevented SAP breaking off from the elastomer network to effectively enhance the water-swelling durability of WSR.

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