Aldehyde Group Content Research Articles

Preparation and properties of walnut cake-based wood adhesive with oxidation modification

Walnut cake has the potential for use in preparing wood adhesives because of its richness in protein and carbohydrate. In this work, walnut cakes were treated with sodium periodate or potassium permanganate and then were directly used as wood adhesives. Their bonding properties, curing performances, thermal properties, and chemical structures were compared. The results showed that: (1) The oxidation by KMnO4was non-selective. The reaction was very intense, accompanied by the great variability of oxidation degree and degradation degree, enormous viscosity of oxidation products, high coating difficulty, and low content of active aldehyde groups. (2) The oxidation by NaIO4 was selective; the reaction was mild and easy to control. More active aldehydes could be produced and the treatment was beneficial for constructing a spatial net structure of the adhesive. (3) Compared with oxidation of KMnO4, the walnut cake adhesive prepared by NaIO4 oxidation exhibited a more compact structure, a higher crosslinking degree, low curing temperature, and high thermal stability after curing; its bonding performances met the requirements for Class II plywood specified in GB/T 17657(2013).

Fire zone forefront residual tar combustion characteristics and functional group transformation mechanism: Appling the based on thermogravimetric and in-situ high-temperature FTIR

When preventing spontaneous combustion disasters in extinguished coal fire zones, the influence of the tar re-ignition phenomenon is often overlooked. Therefore, in this study, using thermogravimetric analysis and high-temperature (630 °C) in-situ infrared technology, the combustion reactivity and real-time evolution mechanism of key functional groups for tar were deeply discussed under oxygen-lean conditions. Additionally, a novel two-step baseline drift correction method for spectral graphs at high temperatures is proposed. The results showed that tar combustion could be divided into two stages: pyrolysis-volatilization mass loss and crosslinked structure oxidation combustion. Reduced oxygen concentration limits the violent and stable rapid combustion of tar-crosslinked structures and reduces the re-ignition tendency of tar. Among, with a decrease in oxygen concentration, H (burnout performance), Cb (the reaction ability in the early stage of ignition) and S (overall combustion performance) decreased, while Ti (mass loss endpoint temperature), Th(burnout temperature), and HF (combustion stability) increased. This provides information for the selection of a reasonable process to prevent tar re-ignition. The contents of methylidene and aldehyde carbonyl in tar increased by approximately 2 and 3.7 times, respectively, compared to those of raw coal. In the first thermal decomposition stage of tar, the aromatic hydrocarbons were relatively stable under the action of the structural framework, whereas aliphatic hydrocarbons continued to decrease. Before burnout, a decrease in oxygen concentration increased the crosslinking ability of tar and delayed the tar burnout process. The contents of aromatic hydrocarbons and aldehyde groups are highly sensitive to the evolution of the oxygen concentration. Specifically, the Kubelka–Munk value of the aromatic hydrocarbons increased from 0.015 to 0.10, while that of aldehyde carbonyl groups increased from 0 to 0.23. Additionally, in the early stage of tar combustion, the volatile mass loss was basically not affected by the time-scale effect, and mass loss endpoint residual mass was approximately 48.11 %. In the later stage of tar combustion, owing to the cumulative of time-scale effect, the tar re-ignition tendency increased, H, Cb, and S increased, and HF decreased from 1.388 to 1.098. This research is helpful guiding disaster prevention and control of tar re-ignition in a fire area, which leads to reburning in the surrounding area.

Absolute contents of aroma-affecting volatiles in cooked rice determined by one-step rice cooking and volatile extraction coupled with standard-addition calibration using HS-SPME/GC–MS

To quantify volatiles in cooked rice, analysis methods for one-step rice cooking and volatile extraction in a single headspace vial, combined with standard addition calibration using solid-phase microextraction and GC–MS were developed and applied to 41 rice varieties with various fragrances and palatability. The newly developed methods significantly improved the qualitative and quantitative recovery of volatiles compared with conventional methods. Among 29 aroma-affecting volatiles, the highest average contents (ng/g) were observed for nonanal (39.30), octanal (13.29), and 1-octen-3-ol (13.18); the total volatile contents of aldehyde, base, and alcohol groups were 4156, 2481, and 1739 ng/g, respectively. Fifteen rice varieties contained 2-acetyl-1-pyrroline in range of 41.37–421.70 ng/g. Although there were no linear correlations among volatiles and the Toyo taste-score, multivariate PLS-DA analysis of the volatile could discriminate between low- and high-palatability rice varieties. The results indicated the accuracy and practicality of the newly developed methods for quantifying volatiles in cooked rice.

A step towards tuning the jute fiber structure and properties by employing sodium periodate oxidation and coating with alginate

This paper outlines a novel simple protocol for tuning the structure and properties of jute using sodium periodate (NaIO4) oxidation and coating with alginate. When compared to the raw jute, fabrics oxidized with a 0.2 or 0.4 % NaIO4 solution for 30–120 min exhibited an increased aldehyde group content (0.185 vs. 0.239–0.398 mmol/g), a significantly increased negative zeta potential (from −8.57 down to −20.12 mV), a slight disruption of fiber crystallinity, 15.1–37.5 % and 27.9–49.8 % lower fabric maximum force and stiffness, respectively. Owing to the removal of hydrophobic surface barrier, decreased crystallinity index and the presence of micropores on the fabrics' surfaces, oxidized fabrics have a 22.3–29.6 % improved ability for moisture sorption compared to raw fabric. Oxidized fabrics characterized by very long wetting times and excellent antioxidant activities (> 98 %), can find applications as hydrophobic packaging materials. To further extend the utilization of jute in biocarpet engineering such as water-binding geo-prebiotic supports, oxidized fabrics were coated with alginate resulting in 7.9–24.9 % higher moisture sorption and 352–660 times lower wetting times than their oxidized counterparts. This modification protocol has never been applied to lignocellulosic fibers and sheds new light on obtaining jute fabrics with tuned structure and properties intended for various applications.

A self-healing hydrogel wound dressing based on oxidized Bletilla striata polysaccharide and cationic gelatin for skin trauma treatment

Skin trauma presents significant treatment challenges in clinical settings. Hydrogels made from naturally-derived polysaccharide have demonstrated great potential in wound healing. Here, a novel in-situ crosslinked self-healing hydrogel was prepared using oxidized Bletilla striata polysaccharide (BSP) and cationic gelatin via a Schiff-base reaction without the need for any chemical crosslinkers. Similar to the natural extracellular matrix, the BSP-gelatin hydrogel (BG-gel) exhibited typical viscoelastic characteristics. The rheological properties, mechanical behavior, porous structure, and degradation performance of BG-gel could be adjusted by changing the aldehyde group content of BSP. Importantly, the hydrogel showed superior hemostatic performance in mouse tail amputation and rat liver incision models. It significantly facilitated wound healing by promoting hair follicles regeneration, blood vessels repair, collagen deposition, and inducing skin tissue remodeling via increased CD31 expression in a full-thickness skin wound rat model. This multifunctional hydrogel holds potential as a wound dressing for skin trauma, offering both hemostasis and expedited healing.

Preparation of aldehyde-graphene quantum dots from glucose for controlled release of anticancer drug

In this study, we prepared graphene quantum dots (GQDs) via a green process using rice straw as a carbon source. The non-toxic nature of GQDs is suitable for application in human body-related research. Furthermore, GQDs possess biodegradability and biocompatibility characteristics, indicating high suitability for applications in the field of drug delivery. Based on the fact that acid-sensitive bonds between GQDs and the drug doxorubicin are formed by aldehyde groups on GQD surfaces, we adopted a semi-modified TEMPO method to partially oxidize the surface functional groups of GQDs without destroying the structure. This enabled an increase in the surface aldehyde group content, which in turn enhanced the drug loading capacity of GQDs. The aldehyde group content of the GQDs was measured via Fourier transform infrared (FTIR) spectroscopy, titration based on the Cannizzaro reaction, and X-ray photoelectron spectroscopy (XPS). The drug loading effect of the GQDs was determined via absorbance measurements at 485 nm on a UV-Vis spectrophotometer. The results indicated that the semi-modified TEMPO method significantly affected the introduction of surface aldehyde groups and the enhancement of the drug loading efficiency in GQDs. Finally, the polymeric material cationic poly (vinylcyclohexene carbonates) (CPVCHCs) was used for the encapsulation of GQDs and regulation of drug release. Under the premise that the total amount of drugs released remains unaffected, the initial burst release of the drug is effectively delayed, which aids in reducing harmful effects of the drug on the human body.

Extracting dialdehyde cellulose nanocrystals using choline chloride/urea-based deep eutectic solvents: A comparative study in NaIO4 pre-oxidation and synchronous oxidation

Dialdehyde cellulose nanocrystals (DCNC) are defined as C2 and C3 aldehyde nanocellulose, which can be used as raw materials for nanocellulose derivatization, owing to the high activity of aldehyde groups. Herein, a comparative study in NaIO4 pre-oxidation and synchronous oxidation is investigated for DCNC extraction via choline chloride (ChCl)/urea-based deep eutectic solvent (DES). Ring-liked DCNC with an average particle size of 118 ± 11 nm, a yield of 49.25 %, an aldehyde group content of 6.29 mmol/g, a crystallinity of 69 %, and rod-liked DCNC with an average particle size of 109 ± 9 nm, a yield of 39.40 %, an aldehyde group content of 3.14 mmol/g, a crystallinity of 75 % can be extracted via optimized DES treatment combined with pre-oxidation and synchronous oxidation, respectively. In addition, the average particle size, size distribution, and aldehyde group content of DCNC were involved. TEM, FTIR, XRD, and TGA results reveal the variation of microstructure, chemical structure, crystalline structure, and thermostability of two kinds of DCNC during extraction even though the obtained DCNC exhibiting different micromorphology, pre-oxidation, or synchronous oxidation during ChCl/urea-based DES treatment can be considered as an efficient approach for DCNC extraction.

Eco‐friendly and non‐toxic lysozyme immobilised on chitosan bacteriostatic agent for strawberry and fresh Tremella fuciformis preservation

SummarySafe and suitable food preservatives can ensure food safety and reduce resource wastage. This paper focuses on the modification of chitosan (CS) using 2,2,6,6‐tetramethylpiperidine‐1‐oxyl radical (TEMPO)/laccase oxidation system and chitosanase. The experimental results showed that the aldehyde group content of the modified CS was increased by 83.3% and the water solubility increased by 4.5 times. In addition, the covalent binding with lysozyme (LSZ) also improved the inhibition effect and the diameter of the inhibition circle was increased by 3 mm. Applying the LSZ‐modified CS to the preservation of strawberries and Tremella fuciformis (T. fuciformis), it was found that the preservation time of strawberries could be extended by 2 days at room temperature, and the microbial spoilage of T. fuciformis was also inhibited. This study provided a CS derivative that could be used as a carrier of natural antibacterial agents, which increased application scope of CS and provided a basis for antimicrobial preservation of food.

Free-aldehyde neutralized and oligohyaluronan loaded bovine pericardium with improved anti-calcification and endothelialization for bioprosthetic heart valves.

The number of patients with valvular heart disease is increasing yearly, and valve replacement is the most effective treatment, during which bioprosthetic heart valves (BHVs) are the most widely used. Commercial BHVs are mainly prepared with glutaraldehyde (Glut) cross-linked bovine pericardial or porcine aortic valves, but the residual free aldehyde groups in these tissues can cause calcification and cytotoxicity. Moreover, insufficient glycosaminoglycans (GAGs) in tissues can further reduce biocompatibility and durability. However, the anti-calcification performance and biocompatibility might be improved by blocking the free aldehyde groups and increasing the GAGs content in Glut-crosslinked tissues. In our study, adipic dihydrazide (ADH) was used to neutralize the residual free aldehyde groups in tissues and provide sites to blind with oligohyaluronan (OHA) to increase the content of GAGs in tissues. The modified bovine pericardium was evaluated for its content of residual aldehyde groups, the amount of OHA loaded, physical/chemical characteristics, biomechanical properties, biocompatibility, and in vivo anticalcification assay and endothelialization effects in juvenile Sprague-Dawley rats. The results showed that ADH could completely neutralize the free aldehyde groups in the Glut-crosslinked bovine pericardium, the amount of OHA loaded increased and the cytotoxicity was reduced. Moreover, the in vivo results also showed that the level of calcification and inflammatory response in the modified pericardial tissue was significantly reduced in a rat subcutaneous implantation model, and the results from the rat abdominal aorta vascular patch repair model further demonstrated the improved capability of the modified pericardial tissues for endothelialization. Furthermore, more α-SMA+ smooth muscle cells and fewer CD68+ macrophages infiltrated in the neointima of the modified pericardial patch. In summary, blocking free-aldehydes and loading OHA improved the anti-calcification, anti-inflammation and endothelialization properties of Glut-crosslinked BHVs and in particularly, this modified strategy may be a promising candidate for the next-generation of BHVs.

E-Nose Discrimination of Almond Oils Extracted from Roasted Kernels.

Almonds contain around 50% fat with a health-promoting fatty acid profile that can be extracted by pressing to obtain high-quality oils. To improve oil sensory properties, the almonds can be subjected to roasting treatments before oil extraction. However, intense thermal treatments may cause the appearance of undesirable volatile compounds causing unpleasant aromas. Thus, oils from almonds subjected to different roasting treatments (30, 45, 60 and 90 min at 150 °C) were analyzed from sensory and the chemical points of view. In addition, an electronic device (E-nose) was used in order to evaluate its usefulness in discriminating samples according to their aromas. The almonds' roasting treatments caused changes in the sensory properties, since defects such as a burned, dry smell or wood fragrance appeared when almonds were subjected to roasting treatments (>45 min). These data agree with the analysis of volatile compounds, which showed an increase in the content of aldehyde and aromatic groups in roasted almonds oils while alcohols and terpenes decreased. Partial least squares discriminant analysis and partial least squares obtained from the E-nose were able to classify samples (97.5% success) and quantify the burned defect of the oils (Rp2 of 0.88), showing that the E-nose can be an effective tool for classifying oils.

The effects of pulsed electric fields treatment on the structure and physicochemical properties of dialdehyde starch

The structural and physicochemical properties changes of corn starch oxidized by sodium periodate under the assistance of pulsed electric fields (PEF) were studied. It was found that dialdehyde starch (DAS) particles produced by PEF-assisted oxidation exhibited shrinkage and pits, and had a larger particle size when compared to the control without PEF. The solubility of the DAS (12 kV/cm PEF- assisted oxidation) improved by 70.2% when compared to the native starch. Increment in the strength of the PEF, led to a decrease in the viscosity of the DAS. In addition, the aldehyde group content of the DAS produced by PEF-assisted oxidation exhibited shrinkage and pits, and had a larger particle size when compared to the control increased by 11.6% when compared with the traditional oxidation method. PEF is an effective method to promote oxidation reaction of starch.

Structural and functional properties of sodium caseinate glycosylated by dextran aldehyde

Glycosylation is an effective method of protein modification which can improve the functional properties of proteins. Traditional protein glycosylation methods are typically limited by slow reaction rates. A method for improving the efficiency of protein glycosylation from different degrees of dextran oxidation with periodate, to obtain dextran aldehydes, is presented. Increased molar ratio between periodate and glucose unit in dextran led to dextran aldehyde with higher aldehyde group content and reduced molecular weight. This is due to an increased oxidation, which increases the degree of glycosylation by 43.22%. Compared with dextran glycosylated products, the emulsifying activity, stability indices and foaming capacity of dextran aldehyde glycosylated products increased by 30.8, 301 and 50%, respectively, with poor foam stability. Dextran aldehyde-modified sodium caseinate presented lower digestibility and could maintain better stability against salt ions and heat treatment. The polysaccharide aldehyde showed great potential for expanding protein modification methods to promote its industrialization.

Obtaining Medical Textiles Based on Viscose and Chitosan/Zinc Nanoparticles with Improved Antibacterial Properties by Using a Dielectric Barrier Discharge.

This study aimed to obtain functional viscose textiles based on chitosan coatings with improved antibacterial properties and washing durability. For that reason, before functionalization with chitosan/zinc nanoparticles (NCH+Zn), the viscose fabric was modified by nonthermal gas plasma of dielectric barrier discharge (DBD) to introduce into its structure functional groups suitable for attachment of NCH+Zn. NCH+Zn were characterized by measurements of hydrodynamic diameter and zeta potential and AFM. DBD-plasma-modified and NCH+Zn-functionalized fabrics were characterized by zeta potential measurements, ATR-FTIR spectroscopy, the calcium acetate method (determination of content of carboxyl and aldehyde groups), SEM, breaking-strength measurements, elemental analysis, and ICP-OES. Their antibacterial activity was determined under dynamic contact conditions. In addition to SEM, the NCH+Zn distributions on viscose fabrics were also indirectly characterized by measuring their absorbent capacities before and after functionalization with NCH+Zn. Washing durability was monitored through changes in the zeta potential, chitosan and zinc content, and antibacterial activity after 1, 3, and 5 washing cycles. The obtained results showed that DBD plasma modification contributed to the simultaneous improvement of NCH+Zn sorption and antibacterial properties of the viscose fabric functionalized with NCH+Zn, and its washing durability, making it suitable for the production of high-value-added medical textiles.

Feasibility study of oxidized naringin as a novel crosslinking agent for crosslinking decellularized porcine Achilles tendon and its potential application for anterior cruciate ligament repair.

Naringin (Nar), a natural flavanone glycoside, has been shown to possess a variety of biological activities, including anti-inflammatory, anti-apoptotic, bone formation, and so forth. In this study, Nar was oxidized by sodium periodate and the oxidized naringin (ONar) was used as a novel biological crosslinking agent. In addition, ONar-fixed porcine decellularized Achilles tendon (DAT) was developed to substitute anterior cruciate ligament (ACL) for researching a novel ACL replacement material. The ONar with a 24 h oxidation time had appropriate aldehyde group content, almost no cytotoxicity, and a good crosslinking effect. The critical characteristics and cytocompatibility of ONar-fixed DAT were also investigated. The results demonstrated that 1% ONar-fixed DAT exhibited good resistance to enzymatic degradation and thermal stability as well as suitable mechanical strength. Moreover, 1% ONar-fixed specimens exhibited excellent L929 fibroblasts-cytocompatibility and MC3T3-E1-cytocompatibility. They also promoted the secretion of hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF) from fibroblasts and bone morphogenetic protein-2 (BMP-2) from osteoblasts. And they also showed the good anti-inflammatory properties in vivo experiments. Our data provided an experimental basis for ONar as a new cross-linking reagent in chemical modification of DAT and ONar-fixed DAT for ACL repair.

Constructing ultra-stable photothermal plastics assisted by carbon dots with photocaged reactivity

Constructing ultra-stable photothermal plastics assisted by carbon dots with photocaged reactivity

Improved Cytocompatibility and Reduced Calcification of Glutaraldehyde-Crosslinked Bovine Pericardium by Modification With Glutathione

Bioprosthetic heart valves (BHVs) used in clinics are fabricated via glutaraldehyde (GLUT) crosslinking, which results in cytotoxicity and causes eventual valve calcification after implantation into the human body; therefore, the average lifetime and application of BHVs are limited. To address these issues, the most commonly used method is modification with amino acids, such as glycine (GLY), which is proven to effectively reduce toxicity and calcification. In this study, we used the l-glutathione (GSH) in a new modification treatment based on GLUT-crosslinked bovine pericardium (BP) as the GLUT + GSH group, BPs crosslinked with GLUT as GLUT-BP (control group), and GLY modification based on GLUT-BP as the GLUT + GLY group. We evaluated the characteristics of BPs in different treatment groups in terms of biomechanical properties, cell compatibility, aldehyde group content detection, and the calcification content. Aldehyde group detection tests showed that the GSH can completely neutralize the residual aldehyde group of GLUT-BP. Compared with that of GLUT-BP, the endothelial cell proliferation rate of the GLUT + GSH group increased, while its hemolysis rate and the inflammatory response after implantation into the SD rat were reduced. The results show that GSH can effectively improve the cytocompatibility of the GLUT-BP tissue. In addition, the results of the uniaxial tensile test, thermal shrinkage temperature, histological and SEM evaluation, and enzyme digestion experiments proved that GSH did not affect the ECM stability and biomechanics of the GLUT-BP. The calcification level of GLUT-BP modified using GSH technology decreased by 80%, indicating that GSH can improve the anti-calcification performance of GLUT-BP. Compared with GLUT-GLY, GLUT + GSH yielded a higher cell proliferation rate and lower inflammatory response and calcification level. GSH can be used as a new type of anti-calcification agent in GLUT crosslinking biomaterials and is expected to expand the application domain for BHVs in the future.

Study on the cross-linking process of carboxylated polyaldehyde sucrose as an anti-wrinkle finishing agent for cotton fabric

Sucrose was oxidized in a two-step oxidation reaction catalyzed by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-laccase and sodium periodate (NaIO4). To generate carboxylated polyaldehyde sucrose (openSu) containing multiple aldehyde and carboxyl groups. The amount of TEMPO and laccase used, as well as the temperature and reaction time were optimized for the oxidation reaction. The successful combination of aldehyde and carboxyl groups of openSu with cellulose was achieved by changing the composition, ratio of the catalyst and the curing conditions. Thereafter, we analyzed the structural characteristics of openSu as well as the aldehyde and carboxyl group content using nuclear magnetic resonance carbon spectroscopy (13C NMR). We found that the optimal finishing conditions were a mixture of magnesium chloride and sodium hypophosphite at a mass concentration ratio of 16 g/L:4 g/L, and curing at 150 °C for 3 min followed by curing at 180 °C for 2 min. There was significant improvement in the anti-wrinkle performance of the openSu-finished fabric, with a wrinkle recovery angle of 258°, whiteness index of 72.1, and a tensile strength rate of more than 65%. We also studied the covalent crosslinking mechanism between openSu and the cotton fabrics.

Structural Changes of Alkali Lignin under Ozone Treatment and Effect of Ozone-Oxidized Alkali Lignin on Cellulose Digestibility

In this study, the structural changes of alkali lignin induced by ozonation were investigated, and the effect of ozone-treated alkali lignin and its mechanism on Avicel enzymatic hydrolysis was examined. The physicochemical properties of alkali lignin were analyzed by FTIR, 1H-13C HSQC NMR, and GPC. It was revealed that ozone pretreatment increased the content of carboxyl and/or aldehyde groups and the negative zeta potential of alkali lignin, which enhanced the electrostatic repulsion between alkali lignin and cellulase; The S/G ratio was reduced, indicating the hydrophobic interaction was diminished. The Langmuir adsorption isotherm showed that the cellulase binding strength of ozone pretreated alkali lignin (OL-pH3, OL-pH7, and OL-pH12 were 16.67, 13.87, and 44.05 mL/g, respectively) was significantly lower than that of alkali lignin (161.29 mL/g). The 72 h hydrolysis yields of Avicel added with OL-pH3, OL-pH7, and OL-pH12 were 55.4%, 58.6%, and 54.9% respectively, which were 2.6–6.3% higher than that of Avicel added with AL (52.3%). This research aimed to reduce the non-productive adsorption between cellulase and lignin by investigating the structural changes of lignin caused by ozone treatment. For the first time, we discovered that ozone-treated alkali lignin has a further promotion effect on the enzymatic digestion of cellulose, providing a green and feasible pretreatment process for the enzymatic hydrolysis of lignocellulose and aiding in the more efficient utilization of biomass.

Electrochemical Oxidation of Starch Investigated by Single‐Current‐Transition Method

AbstractNumerous research has been conducted on starch oxidation, but few reports have described it quantitatively. The oxidation of soluble starch (SS) can be quantitatively determined using a single‐current‐step method, where the aldehyde group content of oxidized starch approaches the maximum value at the voltage jump point. To verify the feasibility of the method, SS electrooxidation and electrochemical synthesis with gelatin (G) are observed and analyzed with reference to voltage changes. As an experimental application, the electrochemical synthesis of SS‐G at varying pH is compared to that of a physical mixture SS+G. According to the changes in the electrosynthesis and differences in the structure and properties of the synthesized products, the single‐current‐step method can be used to distinguish online.

Comparison of the Properties of Cellulose Obtained from Various Sources

The article discusses the structure, structure and properties of cellulose obtained from various natural sources of plant origin. The physical and mechanical properties of celluloses (content of α–cellulose, determination of the mass fraction of pentosans; determination of the copper number; viscosity characteristics; determination of the degree of purity, moisture content and ash content and determination of the average molecular weight, degree of polymerization and content of aldehyde and carboxyl groups), interaction with nitrogen acid as well as the ability of various cellulose samples to complex formation with copper ions.