scholarly journals Effect of pH and pH-shifting on Lignin, Lignin-protein Properties, and Lignin-protein Interactions

2021 ◽  
Author(s):  
Sarocha Pradyawong ◽  
Ruben Shrestha ◽  
Ping Li ◽  
Xiuzhi Susan Sun ◽  
Donghai Wang
Keyword(s):  
Soy Protein ◽  
Water Resistance ◽  
Value Added ◽  
Titration Calorimetry ◽  
Multiple Point ◽  
Hydroxyl Groups ◽  
Binding Interaction ◽  
Lignin Modification ◽  
Protein Properties ◽  
Ph Shifting

Abstract Innovation of high-value added lignin derivatives has become a topic of interest, but lignin modification and utilization remain a challenge due to lignin’s complicated structure. In our previous study, we successfully improved water resistance and adhesion performance of soy protein adhesives using unmodified lignin. This study focuses on lignin modification as well as lignin-protein properties and interactions. Lignin modification was achieved by pH changes and pH-shifting. Cleavage of β-O-4 linkage was observed at pH 8.5 and pH 12, resulting in smaller particle sizes and changes in thermal properties. Partial repolymerization was found after pH-shifting treatments. Lignin increased the strength of protein films under high temperature and significantly enhanced the water resistance of soy protein at pH 12. Cross-linking of protein and lignin took place via carbonyl, amino, and hydroxyl groups. Multiple-point interactions between lignin and protein resulted in a stronger lignin-protein network. Additional lignin-protein complexes with high molecular weight were detected with an elevated lignin concentration at pH 8.5. The binding interaction between lignin and protein, although of non-specific nature, was also observed by isothermal titration calorimetry (ITC). Findings of this study contribute to the further development of green lignin-protein products.

Effect of Coal Structure on Mechanical and Thermal Properties of Coal Filled Soy Protein Composites

2011 ◽  
Vol 236-238 ◽  
pp. 288-291
Author(s):  
Guang Heng Wang ◽  
An Ning Zhou
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Soy Protein ◽  
Water Resistance ◽  
Group Analysis ◽  
Surface Functional Group ◽  
Hydroxyl Groups ◽  
Mechanical And Thermal Properties ◽  
Coal Rank ◽  
Coal Structure

Using different rank coals as filler, coal-soy protein isolate (SPI) composites were prepared by compression molding processing using glycerol as plasticizer. The structure of the coals used were characterized by Fourier transform infrared (FTIR), ultimate analysis, and surface functional group analysis. The effects of coal structure on the mechanical properties, water resistance, and thermal properties were investigated. The results showed that, in different rank coals, the atomic ratio of oxygen to carbon, carboxylic acid groups, phenolic hydroxyl groups, lactone bonds, and aliphatic chains decreased with coal rank. The strength, water resistance, and glass transition temperature of coal-SPI composites decreased with coal rank. Lower ran coal filler with more reactive functional groups caused the composites strong but brittle. While, higher rank coals provide poor mechanical properties for the composites.

Effect of pH and pH-Shifting on Adhesion Performance and Properties of Lignin-Protein Adhesives

2021 ◽  
Vol 64 (4) ◽  
pp. 1141-1152
Author(s):  
Sarocha Pradyawong ◽  
Guangyan Qi ◽  
Meng Zhang ◽  
Xiuzhi S. Sun ◽  
Donghai Wang
Keyword(s):  
Protein Structure ◽  
Soy Protein ◽  
Water Resistance ◽  
Glue Line ◽  
List Type ◽  
Wet Strength ◽  
Wet Adhesion ◽  
Adhesion Performance ◽  
Protein Adhesives ◽  
Ph Shifting

HighlightsLignin improved the wet adhesion strength of soy protein adhesives when pH shifted from 8.5 to 4.5.Lignin increased the water resistance of soy protein adhesives from 5% to 40% at pH 12.Lignin improved the thermal resistance of soy protein adhesives.pH and pH-shifting treatments led to property changes of lignin, soy protein, and lignin-soy protein.Abstract. Concerns about public health and the environment have created strong interest in developing alternative green products. The focus of this research was to study the effect of lignin on soy protein (SP) adhesives under different pH and pH-shifting treatments. Additionally, this research was designed to understand the consequence of pH and pH-shifting treatments on the adhesion performance of SP and lignin-SP (LSP) adhesives as well as the characteristics, solubility, glue line patterns, and physiochemical properties. To study the aggregation, soluble, and denatured stages of protein, the protein solutions were adjusted to pH 4.5, 8.5, and 12, respectively. In addition, the study of pH-shifting treatments was performed at pH 8.5 and 12 to unfold and denature the protein, respectively. The protein structure was then refolded by adjusting the pH to 4.5 in adhesive slurries. The adhesives presented good adhesion performance under dry conditions with wood failure in most treatments, while satisfactory wet adhesion performance was obtained at pH 4.5, 8.5 to 4.5, and 12. Shifting the pH from 8.5 to 4.5 increased the lignin-protein interaction and provided the best improvement in adhesion performance. Lignin strengthened the protein structure, increased the water resistance, and improved the thermal stability of SP adhesives. At an extremely high pH, the water resistance of SP increased from 5% to 40% with the addition of lignin. Lignin showed great potential for increasing the wet strength of SP adhesives. The SP and LSP properties and adhesion performance could be adjusted and improved by pH and pH-shifting processes. Lignin-SP interactions, water resistance, and glue line pattern proved to be significant factors contributing to adhesion performance. Keywords: Adhesive, Lignin, Lignin-protein interactions, pH, pH-Shifting, Protein.

scholarly journals Chitosan Adsorbent Derivatives for Pharmaceuticals Removal from Effluents: A Review

Macromol ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 130-154
Author(s):  
Efstathios V. Liakos ◽  
Maria Lazaridou ◽  
Georgia Michailidou ◽  
Ioanna Koumentakou ◽  
Dimitra A. Lambropoulou ◽  
...  
Keyword(s):  
Emerging Contaminants ◽  
Low Cost ◽  
Value Added ◽  
Ph Effects ◽  
Hydroxyl Groups ◽  
Research Papers ◽  
Natural Polysaccharide ◽  
Best Fitting ◽  
Isotherm And Kinetic Models ◽  
Published Research

Chitin is mentioned as the second most abundant and important natural biopolymer in worldwide scale. The main sources for the extraction and exploitation of this natural polysaccharide polymer are crabs and shrimps. Chitosan (poly-β-(1 → 4)-2-amino-2-deoxy-d-glucose) is the most important derivative of chitin and can be used in a wide variety of applications including cosmetics, pharmaceutical and biomedical applications, food, etc., giving this substance high value-added applications. Moreover, chitosan has applications in adsorption because it contains amino and hydroxyl groups in its molecules, and can thus contribute to many possible adsorption interactions between chitosan and pollutants (pharmaceuticals/drugs, metals, phenols, pesticides, etc.). However, it must be noted that one of the most important techniques of decontamination is considered to be adsorption because it is simple, low-cost, and fast. This review emphasizes on recently published research papers (2013–2021) and briefly describes the chemical modifications of chitosan (grafting, cross-linking, etc.), for the adsorption of a variety of emerging contaminants from aqueous solutions, and characterization results. Finally, tables are depicted from selected chitosan synthetic routes and the pH effects are discussed, along with the best-fitting isotherm and kinetic models.

Wood-Polymer Composite Prepared by In Situ Synthesis of Copolymer within Wood and its Dimensional Stability

2010 ◽  
Vol 150-151 ◽  
pp. 1-5
Author(s):  
Yong Feng Li ◽  
Chi Jiang ◽  
Duo Jun Lv ◽  
Xiao Ying Dong ◽  
Yi Xing Liu
Keyword(s):  
Contact Angle ◽  
Porous Structure ◽  
Polymer Composite ◽  
Dimensional Stability ◽  
Value Added ◽  
Hydroxyl Groups ◽  
Wood Polymer ◽  
Volume Swelling ◽  
Wood Polymer Composite

In order to improve the value-added applications of low-quality wood, a novel Wood-Polymer Composite was fabricated by in-situ synthesis of copolymer from monomers within wood porous structure. The structure was characterized with SEM and FTIR, and its dimensional stability was also tested. The SEM observations showed that copolymer filled up wood pores and contact tightly with wood matrix, indicating strong interactions between them. FTIR analysis indicated that when the monomers copolymerized in situ wood porous structure, they also reacted with wood matrix by reaction of hydroxyl groups and ester groups, indicating chemical bond between the two phases, which is agreement with SEM observations. The volume swelling efficiency and contact angle of such composite were higher than those of wood, respectively, indicating good dimensional stability involving volume swelling efficiency and contact angle. Such composite could be potentially applied in fields of construction, traffic and indoor decoration.

scholarly journals Preparation and Properties of Cyanobacteria-Based Carbon Quantum Dots/Polyvinyl Alcohol/ Nanocellulose Composite

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1143 ◽  
Author(s):  
Li Xu ◽  
Ying Li ◽  
Shiyu Gao ◽  
Yue Niu ◽  
Huaxuan Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Polyvinyl Alcohol ◽  
Water Resistance ◽  
Composite Films ◽  
Barrier Properties ◽  
Carbon Quantum Dots ◽  
Infrared Light ◽  
Quantum Yields ◽  
Hydroxyl Groups ◽  
Light Barrier

Blue luminescent carbon quantum dots (CQDs) were prepared from cyanobacteria by a hydrothermal method. The PL quantum yields of the obtained CQDs was 5.30%. Cyanobacteria-based carbon quantum dots/polyvinyl alcohol/nanocellulose composite films were prepared, which could emit bright blue under UV light. FTIR characterization showed that the composite films had hydroxyl groups on the surface and no new groups were formed after combining the three materials. The photoluminescence (PL) spectra revealed that the emission of the prepared CQDs was excitation dependent. Studies on the water resistance performance and light barrier properties of the composite films showed that they possessed higher water resistance properties and better UV/infrared light barrier properties. Therefore, we report the cyanobacteria-based carbon quantum dots/polyvinyl alcohol/nanocellulose composite films have the potential to be applied in flexible packaging materials, anti-fake materials, UV/infrared light barrier materials and so on.

scholarly journals Advanced Analytical Methods for Phenolics in Fruits

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Nesibe Ebru Kafkas ◽  
Müberra Kosar ◽  
Ayşe Tülin Öz ◽  
Alyson E. Mitchell
Keyword(s):  
Phenolic Compounds ◽  
Value Added ◽  
Biological Tissues ◽  
Carbon Chain ◽  
Polyphenolic Compounds ◽  
Hydroxyl Groups ◽  
Plant Metabolites ◽  
Secondary Plant Metabolites ◽  
Extraction Separation ◽  
Health Promoting

Phenolic compounds are a group of secondary plant metabolites, many with health-promoting properties that are present in all parts of plants. They have an aromatic structure, including either one or more hydroxyl groups giving them the ability to stabilize free radicals and protect biological tissues against damage related to reactive oxygen species. Phenolic compounds are concentrated in the fruit of plants, and therefore, the fruit can be an important dietary source of these phytochemicals, which exist as monomers, or bound to one another. Polyphenolic compounds are classified into different subclasses based upon the number of phenol ring systems that they contain, saturation, and length of the carbon chain that bind the rings to one another. The phenolic acids present in fruit tissues protect the plant against disease, infections, UV radiation, and insect damage. For this reason, the beneficiary effects of phenolic compounds are continually being investigated for their health-promoting properties and for meeting increased consumer demand for healthy nutritious food. Due to the functional properties of polyphenolic compounds, there is increased interest on improving extraction, separation, and quantification techniques of these valuable bioactive compounds, so they can be used as value-added ingredients in foods, pharmaceuticals, and cosmetics. This review provides information on the most advanced methods available for the analysis of phenolics in fruits.

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