Research Progress of Mini-Emulsion in the Wood Industry

2011 ◽  
Vol 393-395 ◽  
pp. 280-283
Author(s):  
Shi Cheng Zhang ◽  
Li Jun Wang ◽  
Jiu Yin Pang
Keyword(s):  
Water Resistance ◽  
Materials Science ◽  
Phenol Formaldehyde ◽  
Rapid Development ◽  
Urea Formaldehyde ◽  
Wood Products ◽  
Research Progress ◽  
Timber Industry ◽  
The Past ◽  
Wide Range

This paper reviews the mini emulsion in the timber industry and development. Introduction of the small foreign Emulsion Synthesis and Application of the latest developments. Mini emulsion adhesive is a rapid development over the past decade and has practical use of new adhesives, with no formaldehyde pollution, water resistance and anti-aging performance, the application of mini emulsion polymerization of a wide range of performance. Discusses the mini prospects for the development of emulsion adhesive. With the development and application of wood-based panel industry continues to expand the range of wood products of a higher water resistance and durability requirements, adhesive application market more widely, the variety is also increasing. Between dissimilar materials, composite wood and the growing need for the traditional timber industry with plastic, urea formaldehyde(UF),phenol formaldehyde(PF),melamine formaldehyde(MF)plastic(the Department of formaldehyde glue) can not fully meet, in which The largest amount of formaldehyde, urea-formaldehyde glue pollution problems caused by people even more widespread concern, it is necessary to vigorously develop new wood adhesive for industrial use. Emulsion is a rapid development over the past decade and have been utility of the new adhesive, with no formaldehyde pollution, water resistance and excellent aging resistance, and adaptability to be glued materials, etc., widely used in wood glue and secondary processing Therefore, great attention by the timber industry, competing for exploitation. Diameter of dispersed droplets in the emulsion 50 ~ 500nm, between macro and micro emulsion between emulsion, known as fine emulsion. Miniemulsion system, in the sub-micron particle size, larger than monomer swollen micelles (diameter of about 40 ~ 50nm), less than the monomer droplets (diameter of about 1000nm), a wide size distribution. Miniemulsion polymerization can not be compared with the advantages of conventional[1], Therefore, polymer and materials science has become a hot research field, in the preparation of the special structure of polymers (such as the core - shell particles, polymer nanoparticles, polymer interpenetrating network structure, etc.) and stable polymer dispersions have Very broad application prospects.

scholarly journals Effect of Technical Aerosil on the Properties of Adhesive Compositions

2021 ◽  
pp. 133-144
Author(s):  
Ekaterina G. Sokolova ◽  
◽  
Dmitry S. Rusakov ◽  
Galina S. Varankina ◽  
Anatoly N. Chubinsky
Keyword(s):  
Water Resistance ◽  
Deep Structure ◽  
Raw Materials ◽  
Phenol Formaldehyde ◽  
Physical Adsorption ◽  
Urea Formaldehyde ◽  
High Water ◽  
Complex Compounds ◽  
Adhesive Compositions ◽  
Wide Range

The main drivers of competition among the products made with the use of adhesive compositions are the toxicity of finished products, the consumption of raw materials and energy resources, the duration of the main technological operations. These drivers can be controlled by using adhesives with different fillings and/or modifications. Adhesives based on phenol-formaldehyde and melamine-urea-formaldehyde resins are used to produce plywood with increased water resistance. Apart from resins, adhesives usually contain hardeners, fillers, and modifiers that affect the properties of the finished product. Technical aerosol is one of the modifiers of synthetic resins with a wide range of action. Aerosil is characterized by three types of interaction: physical adsorption, chemical adsorption (formation of hydrogen bridges by silanol groups), and chemical reactions on the surface layer. The chemical composition of aerosil was analyzed. Technical aluminum fluoride (AlF3) is of particular interest. It can interact with alkali metal fluorides with the formation of complex compounds that improve polymer structuring. The acids that make up aerosil reduce the pH to 2.0–3.5, so they can be catalysts for the curing process of melamine-urea-formaldehyde resins. The effect of technical aerosil on the properties of adhesive systems based on phenol-formaldehyde and melamine-ureaformaldehyde resins has been studied. Viscosity, curing time, and wetting ability of adhesive compositions were determined. The obtained results indicate the possibility of using this modifier in the composition of phenol-formaldehyde and melamine-urea-formaldehyde resins up to 15 pts. wt. The nature of the aerosil action on adhesive compositions was determined using IR spectroscopy. Analysis of the results showed that aerosil promotes deep structure formation of the polymer by increasing the molecular weight of the molecules. These bonds make it possible to form a more structured polymer with bound formaldehyde. Studies of the effect of aerosil on the properties of finished products were carried out. At the same time, an increase in performance indicators was found: the strength of adhesion increases, the toxicity of plywood decreases. The results of experiments on the effect of technical aerosil, taking into account the reduction of bonding time can be applied in the development of technological processes for obtaining plywood of high water resistance. For citation: Sokolova E.G., Rusakov D.S., Varankina G.S., Chubinsky A.N. Effect of Technical Aerosil on the Properties of Adhesive Compositions. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 133–144. DOI: 10.37482/0536-1036-2021-3-133-144

scholarly journals Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim
Keyword(s):  
Raw Materials ◽  
Phenol Formaldehyde ◽  
Raw Material ◽  
Wood Industry ◽  
Suitable Material ◽  
The Past ◽  
Wide Range ◽  
Recent Developments ◽  
Sustainable Materials ◽  
Materials Used

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.

Twentieth-Century Influences on the Development in Britain of Services for Child and Adolescent Psychiatry

1991 ◽  
Vol 159 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Christopher J. Wardle
Keyword(s):  
Rapid Development ◽  
Child And Adolescent Psychiatry ◽  
Therapeutic Interventions ◽  
Teaching Hospitals ◽  
The Past ◽  
Child Guidance ◽  
Wide Range ◽  
The Media ◽  
Post War ◽  
And Control

Modern comprehensive multidisciplinary mental-health services for children and adolescents have four origins: psychology from 1890, psychoanalysis from 1906, the child-guidance movement from 1920, and the children's departments of psychiatric teaching hospitals from 1930. Post-war changes in society and reform, especially the NHS Act 1946, contributed to rapid development of services and an increasingly wide range of sophisticated therapeutic interventions; professional and interdisciplinary associations and trans-Atlantic exchange were also influential. In the last three decades a succession of official inquiries, reports, legislation and reorganisations have had a damaging effect. Children and their services have been prey tocauses célèbres,fashion and the exaggerated fads and foibles of the media and politicians; they have thrived best when society and their carers were tolerant, and loving, sought good qualities to augment, not evil to exorcise, and succeeded in balancing structure and control with flexibility and freedom to grow. Planners should review the past before acting.

Optimising the process for production of high performance bagasse-based composites from rice bran-UF adhesive system

2014 ◽  
Vol 43 (4) ◽  
pp. 212-218 ◽  
Author(s):  
Altaf H. Basta ◽  
Houssni El-Saied ◽  
Emad M. Deffallah
Keyword(s):  
Environmental Impact ◽  
High Performance ◽  
Water Resistance ◽  
Urea Formaldehyde ◽  
Adhesive System ◽  
Wood Products ◽  
Particle Board ◽  
Wood Industry ◽  
Content Type ◽  
Board Strength

Purpose – The purpose of this paper is to prepare high-performance agro-based composites from the non-toxic rice bran-urea-formaldehyde (RB-UF) adhesive system. Investigations have continued for production high performance agro-based composites using environmentally acceptable approaches. The utilisation of such system with the available used local agro-based wood products (sugar-cane bagasse, SCB) adds economic value and helps reducing the environmental impact of commercial urea-formaldehyde (UF) adhesive, and most importantly, provides a potentially inexpensive alternative to the existing commercial artificial wood-panel mills. Design/methodology/approach – Optimising the process for incorporating the RB in UF, as wood adhesive for binding the bagasse fibres, was carried out, by partially replacing commercial UF by denaturalised RB in slurry (wet) and dry form or through synthesis of UF. The denaturalisation of RB was carried out at different pHs (10-11) and at temperature 60°C for two hours. While incorporating the RB during synthesis of UF, it was carried out according to the method reported elsewhere. The formulation of adhesive components, pH value of the denaturalisation stage and the process of incorporating the RB were optimised. Assessment of the role of RB adhesive was specified from its free-formaldehyde (HCHO) content, as well as the properties (mechanical and physical properties) of the produced composites of bagasse particle board type, in comparison with the environmental impact of commercial thermosetting resin (UF). Findings – The promising adhesive system exhibits improvement in the environmental performance (as E1 type) over a commercially UF adhesive (as E2 type), besides providing boards fulfill the requirements of grade H-3 (according to ANSI A208.1 (NPA1993). This adhesive system was resulted from replacing 30 per cent of UF by denalturalised RB (at pH 10) in slurry form. Where, its reduction in free-HCHO reached 53 per cent, as well as modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB) and TS of the produced boards were approximately 24.2 N/mm2, approximately 3753 N/mm2, approximately 0.84 N/mm2 and approximately 11.4 per cent, respectively. Research limitations/implications – The eco-adhesive with relatively high percentage of low-cost commercial UF (70 per cent) and 30 per cent RB, as oil production by-product, in slurry form provides good board strength and is environmentally friendly compared to SCB-based composite properties, with that produced from commercial UF. The mechanical (MOR, MOE and IB) and water-resistance properties of the produced composite comply with the standard values. Practical implications – The approach provided low HCHO-free UF adhesive with good comparative board strength and water resistance and reasonable working life. Replacing 30 per cent of UF by RB in slurry form and denaturalised at pH 10 is considered a promising inexpensive alternate adhesive (as E1) in the wood industry based on SCB wastes. Social implications – Incorporating the RB by-product of oil production to commercial UF will be beneficial for saving the health of wood co-workers and motivating the wood mill to export its wood products. Originality/value – It provided a potentially simple way to improve both the utilisation of commercial UF and SCB as industrial substrates for particle-board production. This will benefit farmers, local wood mills in Upper Egypt, significantly. Meanwhile, incorporating low percentage of RB, as oil-mill by-products, is promising to partly replace UF resin in the wood industry, minimising formaldehyde emission or toxic gasses during board formation.

Advances in nano-biomaterials and their applications in biomedicine

2021 ◽  
Author(s):  
Yogita Patil-Sen
Keyword(s):  
Tissue Engineering ◽  
Regenerative Medicine ◽  
Biomedical Applications ◽  
Materials Science ◽  
Disease Diagnosis ◽  
Biological Properties ◽  
The Past ◽  
Physico Chemical ◽  
Wide Range ◽  
Biomolecules Detection

Nano0technology has received considerable attention and interest over the past few decades in the field of biomedicine due to the wide range of applications it provides in disease diagnosis, drug design and delivery, biomolecules detection, tissue engineering and regenerative medicine. Ultra-small size and large surface area of nanomaterials prove to be greatly advantageous for their biomedical applications. Moreover, the physico-chemical and thus, the biological properties of nanomaterials can be manipulated depending on the application. However, stability, efficacy and toxicity of nanoparticles remain challenge for researchers working in this area. This mini-review highlights the recent advances of various types of nanoparticles in biomedicine and will be of great value to researchers in the field of materials science, chemistry, biology and medicine.

scholarly journals A Review on Metal- and Metal Oxide-Based Nanozymes: Properties, Mechanisms, and Applications

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Qianwen Liu ◽  
Amin Zhang ◽  
Ruhao Wang ◽  
Qian Zhang ◽  
Daxiang Cui
Keyword(s):  
Metal Oxide ◽  
Catalytic Mechanism ◽  
Clinical Medicine ◽  
Low Cost ◽  
Rapid Development ◽  
Research Progress ◽  
Future Research ◽  
Chemical Production ◽  
The Past ◽  
Metal Oxide Nanomaterials

AbstractSince the ferromagnetic (Fe3O4) nanoparticles were firstly reported to exert enzyme-like activity in 2007, extensive research progress in nanozymes has been made with deep investigation of diverse nanozymes and rapid development of related nanotechnologies. As promising alternatives for natural enzymes, nanozymes have broadened the way toward clinical medicine, food safety, environmental monitoring, and chemical production. The past decade has witnessed the rapid development of metal- and metal oxide-based nanozymes owing to their remarkable physicochemical properties in parallel with low cost, high stability, and easy storage. It is widely known that the deep study of catalytic activities and mechanism sheds significant influence on the applications of nanozymes. This review digs into the characteristics and intrinsic properties of metal- and metal oxide-based nanozymes, especially emphasizing their catalytic mechanism and recent applications in biological analysis, relieving inflammation, antibacterial, and cancer therapy. We also conclude the present challenges and provide insights into the future research of nanozymes constituted of metal and metal oxide nanomaterials.

Research Advance of Electrochemical Sensor Fabricated with Nanomaterials and their Application

2011 ◽  
Vol 418-420 ◽  
pp. 2126-2129 ◽  
Author(s):  
Ying Gao ◽  
Qian Xiang ◽  
Jing Qiu Liu ◽  
Qun Qi Wang ◽  
Juan Tang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Specific Surface ◽  
Electrochemical Sensor ◽  
Surface Area ◽  
Active Sites ◽  
Rapid Development ◽  
Research Progress ◽  
The Past ◽  
Research Advance ◽  
Carbon Nanotube Composite

Nanomaterials include nanometal, nanooxide, carbon nanotube, carbon nanotube composite and other types of nanomaterials. They provide a significant way for the manufacture of sensors due to their small size, larger specific surface area, surface atomic slots insufficiency and more active sites. The rapid development of electrochemical sensor fabricated with nanomaterials is of significant value. In this article, we address some of the main advances in this field over the past few years, discussing the research progress of electrochemical sensor fabricated with nanomaterials and their application.

scholarly journals Advances in Density-Functional Calculations for Materials Modeling

2019 ◽  
Vol 49 (1) ◽  
pp. 1-30 ◽  
Author(s):  
Reinhard J. Maurer ◽  
Christoph Freysoldt ◽  
Anthony M. Reilly ◽  
Jan Gerit Brandenburg ◽  
Oliver T. Hofmann ◽  
...  
Keyword(s):  
Density Functional ◽  
Materials Science ◽  
Inorganic Materials ◽  
The Past ◽  
Biological Matter ◽  
Materials Modeling ◽  
Wide Range ◽  
Low Dimensional ◽  
Low Dimensional Materials

During the past two decades, density-functional (DF) theory has evolved from niche applications for simple solid-state materials to become a workhorse method for studying a wide range of phenomena in a variety of system classes throughout physics, chemistry, biology, and materials science. Here, we review the recent advances in DF calculations for materials modeling, giving a classification of modern DF-based methods when viewed from the materials modeling perspective. While progress has been very substantial, many challenges remain on the way to achieving consensus on a set of universally applicable DF-based methods for materials modeling. Hence, we focus on recent successes and remaining challenges in DF calculations for modeling hard solids, molecular and biological matter, low-dimensional materials, and hybrid organic-inorganic materials.

Microfluidic Droplet Technique for In Vitro Directed Evolution

2010 ◽  
Vol 63 (9) ◽  
pp. 1313 ◽  
Author(s):  
Nan Wu ◽  
John Oakeshott ◽  
Sue Brown ◽  
Christopher Easton ◽  
Yonggang Zhu
Keyword(s):  
Directed Evolution ◽  
High Throughput Screening ◽  
Rapid Development ◽  
Dna Amplification ◽  
Industrial Applications ◽  
The Past ◽  
Wide Range ◽  
In Vitro Protein Expression ◽  
Mutant Genes

Increasingly over the past two decades, biotechnologists have been exploiting various molecular technologies for high-throughput screening of genes and their protein products to isolate novel functionalities with a wide range of industrial applications. One particular technology now widely used for these purposes involves directed evolution, an artificial form of evolution in which genes and proteins are evolved towards new or improved functions by imposing intense selection pressures on libraries of mutant genes generated by molecular biology techniques and expressed in heterologous systems such as Escherichia coli. Most recently, the rapid development of droplet-based microfluidics has created the potential to dramatically increase the power of directed evolution by increasing the size of the libraries and the throughput of the screening by several orders of magnitude. Here, we review the methods for generating and controlling droplets in microfluidic systems, and their applications in directed evolution. We focus on the methodologies for cell-based assays, in vitro protein expression and DNA amplification, and the prospects for using such platforms for directed evolution in next-generation biotechnologies.

A review of progress on high nitrogen austenitic stainless-steel research

2021 ◽  
Vol 11 (12) ◽  
pp. 1901-1925
Author(s):  
Shuai Li ◽  
Chengsong Zhang ◽  
Jiping Lu ◽  
Ruiduo Chen ◽  
Dazhi Chen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Research Progress ◽  
High Nitrogen ◽  
Friction Stir ◽  
The Past ◽  
Wide Range

High nitrogen austenitic stainless steels are commonly used in wide range of applications because of their excellent properties, attracting super attention over the past decades. Compared with other metal materials, high nitrogen austenitic stainless steel increases the nitrogen content under the premise that the structure is austenite, giving it excellent mechanical properties and corrosion resistance. Based on relevant documents from the past ten years, this article summarizes and compares three preparation methods for high nitrogen austenitic stainless steels, namely: powder nitriding, melt nitriding and bulk nitriding. They can be divided into six categories according to other differences as explained by the latest research progress on strengthening and toughening mechanism for high nitrogen austenitic stainless steels: composite structure strengthening, fine grain strengthening, precipitation strengthening and strain strengthening. This article also reviews the research progress on excellent properties of high nitrogen stainless steel, including strength, hardness and corrosion resistance. It further describes the emerging nickel-free high nitrogen austenitic stainless steels and its biocompatibility. Welding applications of high nitrogen austenitic stainless steels are also described from three aspects: friction stir welding, arc welding and brass solder. Finally, this article puts forward the development direction of high nitrogen austenitic stainless steels in the future.

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