scholarly journals Development of Kraft Lignin Chemically Modified as a Novel Crosslinking Agent for the Synthesis of Active Hydrogels

2021 ◽  
Vol 11 (9) ◽  
pp. 4012
Author(s):  
Diana Rico-García ◽  
Luis Guillermo Guerrero-Ramírez ◽  
Leonardo Ramses Cajero-Zul ◽  
Euologio Orozco-Guareño ◽  
Edgar Benjamin Figueroa-Ochoa ◽  
...  

In this research a chemical modification of kraft lignin was carried out using a basic nucleophilic substitution reaction (NSA) in order to functionalize it as a novel crosslinking agent for the synthesis of active hydrogels. The chemical modification success of the synthesized crosslinker was demonstrated by using several techniques such as volumetry probes, FTIR, 1H-NMR and DSC. Thus, the obtained materials were employed during the synthesis of acrylic acid-based hydrogels, due to its high-water absorption capacity to evaluate their retention potential of heavy metal ions. Characterization of the active hydrogels were performed by FTIR and SEM, showing the specific signals corresponding to the base monomers into the polymer skeleton and the efficiency of modified kraft lignin as a novel crosslinking agent. Additionally, to demonstrate the potential use of these hydrogels in wastewater treatment, metal ions adsorption experiments were conducted, showing adsorption percentages higher than 90% and 80% for Pb2+ and Cu2+, respectively.

Gels ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 5
Author(s):  
Samuel Mandin ◽  
Samuel Moreau ◽  
Malika Talantikite ◽  
Bruno Novalès ◽  
Jean-Eudes Maigret ◽  
...  

Bio-based aerogels containing cellulose nanofibrils (CNFs) are promising materials due to the inherent physical properties of CNF. The high affinity of cellulose to plant hemicelluloses (xyloglucan, xylan, pectin) is also an opportunity to develop biomaterials with new properties. Here, we prepared aerogels from gelled dispersions of CNFs and xyloglucan (XG) at different ratios by using a freeze-casting procedure in unidirectional (UD) and non-directional (ND) manners. As showed by rheology analysis, CNF and CNF/XG dispersions behave as true gels. We investigated the impact of the freezing procedure and the gel’s composition on the microstructure and the water absorption properties. The introduction of XG greatly affects the microstructure of the aerogel from lamellar to cellular morphology. Bio-based aerogels showed high water absorption capacity with shape recovery after compression. The relation between morphology and aerogel compositions is discussed.


Author(s):  
Adegbenle Bukunmi O

Laterite samples from Ede area with particle components of 19.7% clay, 32.8% silt and 47.5% sand was stabilized with combined cement, lime and bitumen and test for Compressive strength, Linear Shrinkage, Permeability and Water Absorption. The stabilizers were mixed with laterite soil in different ratios and percentage. The laterite carried 90% which is constant while the three stabilizers shared the remaining 10% in varying form. After 28 days of curing, laterite stabilizer with 90% of laterite, 8% of cement, 1% lime and 1% bitumen (LCLB1) possessed compressive strength of 2.01N/mm2. It Water Absorption Capacity was 3.05%. LCLB4 stabilizer (90% laterite, 6% cement, 2% lime and 2% bitumen) has the same compressive strength with LCLB1 stabilizer but with a high Water Absorption Capacity of 4.2%. The stabilizer of 90% laterite, 3.33% cement, 3.33% lime and 3.33% of bitumen (LCLB8) has the lowest compressive strength of 0.74N/mm2 and the highest Water Absorption Capacity of 5.39%. The results shows that LCLB1 stabilizer is a better stabilizer for strength and blocks made from laterite stabilized with it stand a good alternative to sand Crete blocks in building constructions. The combination of these stabilizers in order to determine a most economical volume combination for optimum performance is highly possible and economical.


2020 ◽  
Vol 8 (25) ◽  
pp. 12613-12622
Author(s):  
Xiaosai Hu ◽  
Qiao Wang ◽  
Qing Liu ◽  
Zongjin Li ◽  
Guoxing Sun

Villi-like structure greatly improved the water absorption capability of super water absorbing hydrogels (SAH).


2014 ◽  
Vol 805 ◽  
pp. 116-121 ◽  
Author(s):  
Greyce Yane Honorato Sampaio ◽  
Ana C.B.M. Fook ◽  
Thiago Bizerra Fideles ◽  
M.E.R.R.M. Cavalcanti ◽  
Marcus Vinícius Lia Fook

Currently researchers has pointed chitosan as one of the viable alternatives for application as scaffolds in tissue regeneration, mainly due to its availability, biocompatibility, biodegradability and ability to chemical modifications, among them, the crosslinking. With the growing number of investigations of crosslinking agents from natural sources and its applicability, this work focuses on the development and microstructural characterization of chitosan scaffolds and chitosan crosslinked with genipina using the technique of freeze drying. Solutions were prepared with chitosan concentration of 2% (w / t), and genipin 0.15% (w / t) and 0.3% (w / t). These were frozen at-20 ° C and ≈ 196 ° C, and lyophilized. The effect of different concentrations of genipin and freezing rates of the solutions in the porous architecture of the scaffolds were evaluated by Scanning Electron Microscopy (SEM), Optical Digital Microscopy 2D and 3D (OM) and testing the Degree of Swelling (DS). The SEM analysis revealed the formation of a three dimensional structure with pores and / or channels interconnected, influenced by the freezing rate and addition of crosslinking agent, these variables also influence the absorption capacity of the scaffolds. It was observed by OM, the effectiveness of the crosslinking with genipin, through points of fluorescence presented.


2014 ◽  
Vol 887-888 ◽  
pp. 669-673 ◽  
Author(s):  
Wan Tao Guo ◽  
Ling Bin Lu ◽  
Jian Jun Shi ◽  
Jia Yu Sun

Carboxymethyl chitosan aerogel was prepared by freeze-drying method with glutaraldehyde as crosslinking agent. The effect of different concentrations of crosslinking agent and solvent on the gel time and porosity was investigated. The absorption capacity of aerogel was investigated with different oils (gasoline, diesel oil, peanut oil, dimethyl silicone). The results were shown as 1) the highest porosity of the aerogel was 95.01% and the lowest density was 0.026g/cm3. 2) The optimum preparation condition was the concentration of crosslinking agent 20%, the solvent concentration 2%. Oil absorption capacity of the aerogel was up to the maximum of 28.6g/g (to dimethyl silicone), which was higher than to the other three oils. This work offered a preparation method for the high porosity, high oil-absorbing massive carboxymethyl chitosan aerogel and revealed its potential application in the treatment of oil pollution.


1966 ◽  
Vol 46 (5) ◽  
pp. 545-551 ◽  
Author(s):  
H. H. Marshall

Significant differences in the water absorption capacity of mature pea seeds were found between lines or varieties within and between each of four genetically different seed types, round, wrinkled, "new" wrinkled, and "double" wrinkled. The differences in water absorption were positively correlated with sugar content of immature peas. They were also negatively correlated with seed weight in lines with the genes for new wrinkled.Peas with both classical (rr) and the genes for new wrinkled have high water absorption indices and small seeds. Immature seeds contain from 14.6 to 17.0% sugar or about 1% more than classical wrinkled varieties.


2020 ◽  
pp. 74-83
Author(s):  
Ju. V. Ushakova ◽  
E. M. Paskova ◽  
G. E. Rysmukhambetova ◽  
T. B. Kulevatova

The article presents experimental data on the assessment of the rheological properties of dough from new types of flour, formed on the basis of cumulative curves using the Mixolab device. The data of mixolabograms and radial diagrams (Mixolab profiler) made it possible to reveal the existing differences in the parameters of the rheological profile and Mixolab indices. The object of the study is composite mixtures of gluten-free flours: No. 1 is 50% of pumpkin and 50% of corn flour, No. 2 is 50% of linseed and 50% of corn flour, No. 3 – 50% of rice and 50% of corn flour, No. 4 – 75% of linseed and 25% of corn flour, No. 5 is 30% of linseed and 70% of rice flour. The use of composite mixtures is promising due to high oven rise and low starch thickening because of its high water absorption capacity (WAC). In addition, there is certain economic efficiency, since it is possible to produce more dough at a lower cost.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Karina Ríos-Ríos ◽  
Edith González-Mondragón ◽  
Maira Segura-Campos ◽  
Mariela Ramírez-Jiménez ◽  
Jesús López-Luna ◽  
...  

The physicochemical and nutritional characteristics ofColocasia antiquorum(taro coconut or Chinese taro) starch cultivated in Oaxaca, Mexico, were determined. The granules ofColocasia antiquorumpresented a truncated ellipsoidal shape. The chemical composition analysis showed levels of moisture, ash, protein, fat, fiber, and NFE in a dry base of 10.29, 0.18, 2.0, 0.05, 0.01, and 97.76, respectively, as well as amylose and amylopectin contents of 13.05 and 86.95%, respectively. Gelatinization temperatures, onset (To), peak (Tp), and final (Tf), were 72.86, 82.91, and 93.05°C, respectively. Solubility, swelling power (SP), and water absorption capacity (WAC) correlate directly with increments in temperature. Transmittance value (% T) for taro coconut was 0.3% and its apparent viscosity ranged from 100 to 150 cp. The nutritional characterization ofColocasia antiquorum’s starch amounted to 97.88% of total starch (TS), while available (AS) and resistant starch (RS) were 93.47 and 3.70%, respectively.Colocasia antiquorum, grown in Oaxaca, Mexico, is an unconventional source of starch with added value due to its potential use as an ingredient in the development of new products or as a substitute for conventional starch sources in industrial processes.


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