Alkyd resins: From down and out to alive and kicking

Alkyd resins have been introduced in the 1930s as binders for paints. Their compatibility with many polymers and the extremely wide formulating latitude made them suitable for the production of a very broad range of coating materials. This includes do-it-yourself paints and varnishes for wood and metal, road marking paints, anticorrosive paints, nitrocellulose lacquers, two-component isocyanate curing coatings, acid curing coatings, stoving enamels, etc. Except for phthalic anhydride, being of petrochemical origin, the other raw materials used in the synthesis of the alkyds are from biologically renewable sources. This, combined with their biological degradability, makes them very interesting binders from an ecological point of view. Solvents which are used to reduce and adjust the paint viscosity are the only concern with respect to the ecological aspects of the alkyd paints. In recent years, however, we witness quite an activity in designing alkyd emulsions and high solids alkyds which can serve as binders for environmentally friendly coatings.     

An overview of luminescent bio‐based composites

The development of inorganic/organic composite materials represents a fast‐growing interdisciplinary area in materials science and engineering. In this topic, a key idea is the production of composites comprising biopolymers and functional inorganic phases that could replace conventional materials in several high‐technology applications. Following this concept, the use of different polymers from renewable sources, such as cellulose, starch, alginate, and chitosan, have gained great relevance because of their renewable nature, potential biocompatibility, and biodegradability, as well as specific physicochemical properties. The combination of these biopolymers with different fillers (including inorganic nanoparticles (NPs), clusters, or ions) allows the design of innovative bio‐based materials with specific and/or improved properties, namely, optical, mechanical, and barrier properties, luminescence, and biological properties (as antimicrobial activity and biocompatibility). This review will focus on the most important synthetic approaches, properties, and applications of luminescent bio‐based composites obtained by combining different biopolymers and fillers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41169.     

Recent Advances in Lipid Derived Bio-Based Materials for Food Packaging Applications

The utilization of lipids is presently in the spotlight of food industry as they are one of novel renewable and sustainable raw materials. Lipids derived materials are considered as a promising alternate to petro-based polymers as they are sustainable, biorenewable, biodegradable, and environmentally benign. These unique attributes draw the attention of scientific community for the use of lipids in food packaging applications with a potential to compete with fossil fuel derived polymers. This paper reviews recent advances in the use of lipids and their effect on the barrier, antimicrobial, antioxidant, and mechanical properties of films, coating and nanocomposites for food packaging applications. Modification of lipids and its chemical interactions with other biopolymers during processing for the synthesis of different materials are also discussed. Global patents and research trend in use of lipids for the preparation of biocomposites are also described. The role of lipids in the circular economy is highlighted and life cycle assessment of lipids derived products is outlined with examples. The review is concluded with synoptic view of existing and forthcoming potential use of lipids in various food packaging applications.     

Natural Polymers from Biomass Resources as Feedstocks for Thermoplastic Materials

With the objective of a more sustainable circular economy, one long‐term goal is the utilization of renewable resources as feedstock for the production of polymer‐based materials. In order to successfully process such materials using existing industrial‐scale technologies or even recycling processes, the natural polymers must have thermoplastic properties. With only a few exceptions, natural polymers are not thermoplastic. However, chemical and physical modification techniques are able to induce thermoplasticity in natural polymers from biomass resources such as cellulose, lignin, and chitin. Modification techniques focus on masking the hydroxyl groups to disrupt dense hydrogen bonding and so enable polymer chain mobility upon heating. The introduction of long alkyl chains into the polymer backbone effectively improves the thermoplastic processing of natural polymers. With regard to polymer blending, chemical grafting and graft copolymerization are powerful tools for enhancing compatibility. For both chemical and physical modification, solvents such as ionic liquids and deep eutectic solvents are currently being explored for biomass and fiber processing and show promise for the future development of thermoplastic biopolymers. This review describes possible modifications, potential processing difficulties, and gives a summary of relevant studies described in the scientific literature.     

Natural Gums as Oleogelators

The natural gums used as high molecular weight oleogelators are mainly polysaccharides that deliver a broad spectrum of possible utilization methods when structuring liquid fats to solid forms. The review discusses a natural gums’ structuring and gelling behavior to capture the oil droplets and form the water/oil gelling emulsions basing on their structural conformation, internal charge, and polymeric characteristics. The specific parameters and characteristics of natural gums based oleogels are also discussed. In the future, oleogels may eliminate saturated and trans fats from food products and allow the production of low-fat products, thus reducing the environmental damage caused by the excessive use of palm oil. The increasing knowledge of molecular interaction in polysaccharide chains of natural gums allows to apply more sustainable and wiser strategies towards product formulation. Innovative solutions for using oleogels based on natural polysaccharide biopolymers let incorporate them into the food matrix and replace fats completely or create blends containing the source of fats and the addition of the oleogel. The profound insight into molecular characteristics of natural gums in the function of being oleogelators is presented.     

RETRACTED ARTICLE: Towards understanding polyhydroxyalkanoates and their use

It is fact that Polymers and their products have changed the face of the world in all the field of the technology. They are the future of the coming up generation of the research of the world. But this is also fact that these synthetic non biodegradable polymers have created a tough situation for the living being for a healthy life. Polyhydroxyalkanoates are polyesters produced by bacteria as intracellular storage materials in response to a variety of nutritional and environmental conditions, such as nitrogen limitation Polyhydroxyalkanoates (PHAs) are gaining increasing attention in the biodegradable polymer market due to their promising properties such as high biodegradability in different environments, not just in composting plants, and processing versatility. Indeed among biopolymers, these biogenic polyesters represent a potential sustainable replacement for fossil fuel-based thermoplastics. Most commercially available PHAs are obtained with pure microbial cultures grown on renewable feedstocks (i.e.glucose) under sterile conditions but recent research studies focus on the use of wastes as growth media.PHA can be extracted from the bacteria cell and then formulated and processed by extrusion for production of rigid and flexible plastic suitable not just for the most assessed medical applications but also considered for applications including packaging, moulded goods, paper coatings, non-oven fabrics, adhesives, films and performance additives. The present paper reviews the PHAs, their main properties, processing aspects, commercially available ones, as well as limitations and related improvements being researched,with specific focus on potential applications of PHAs in packaging.     

Pressure Sensitive Adhesives Based on Oleic Acid

Existing pressure sensitive adhesives (PSA) are mostly based on petrochemical‐based polymers. This study reveals a new class of bio‐based polymers that can be used as PSA. The polymers are hydroxyl‐containing polyesters from the step‐growth polymerization of epoxidized oleic acid (EOA), an AB‐type monomer containing both a carboxylic acid group (A) and an epoxy group (B). The monomer is derived from epoxidation of renewable methyl oleate followed by selective hydrolysis of the ester group. The polymers (PEOA) of EOA were characterized for their chemical structure and molecular weight. The PEOA after being cured with a very small amount of a crosslinking agent could serve as a PSA with high peel strength, high tack force, superior shear resistance, excellent aging resistance, and excellent thermal stability. The PSA contains 99 wt% of green renewable materials. The PSA were also characterized for their viscoelastic properties and thermal properties.     

Synthesis and characterization of hydrogenated sorbic acid grafted dicyclopentadiene tackifier

Hydrocarbon resins, which are defined as low molecular weight, amorphous, and thermoplastic polymers, are widely used as tackifier for various types of adhesives, as processing aids in rubber compounds, and as modifiers for paint and ink products, and for plastics polymers such as isotactic polypropylene. Typically, hydrocarbon resins are non-polar, and thus highly compatible with non-polar rubbers and polymer. However, they are poorly compatible with polar system, such as acrylic copolymer, polyurethanes, and polyamides. Moreover, recently the raw materials of tackifier from naphtha cracking had been decreased because of light feed cracking such as gas cracking. To overcome this problem, in this study, novel hydrocarbon resins were designed to have a highly polar chemical structure. And, it was synthesized by Diels–Alder reaction of dicyclopentadiene monomer and sorbic acid from blueberry as renewable resources. Acrylic resins were formulated with various tackifiers solution including hydrogenated sorbic acid grafted dicyclopentadiene tackifier in acrylic adhesive and rolling ball tack, loop tack, 180° peel adhesion strength, and shear adhesion strength were measured. The properties depend on the softening point and polar content of tackifiers.     

Synthesis and characterization of petroleum and biobased epoxy resins: a review

Petroleum based epoxy resins exhibit various excellent properties such as adhesion, mechanical performance, electrical insulation and chemical resistance. There is wide concern towards depletion of non‐renewable resources, climate change and finding renewable alternatives for petroleum based materials to reduce the emission of greenhouse gases. This review mainly draws attention towards the utilization of renewable resource based epoxy resin derived from lignocellulosic biomass, furan, tannins, itaconic acid, rosin acid and bio‐oil etc. Without altering the mechanical and thermal properties much, epoxy resins derived from renewable materials have been widely investigated. The last two decades have witnessed an exponential growth in using bio‐derived products, which has been driven by the need to replace petroleum based materials, reduce fuel consumption and lower the overall environmental impact. © 2018 Society of Chemical Industry     

Chitosan Derivatives as Important Biorefinery Intermediates. Quaternary Tetraalkylammonium Chitosan Derivatives Utilized in Anion Exchange Chromatography for Perchlorate Removal

There has recently been great interest in the valorization of biomass waste in the context of the biorefinery. The biopolymer chitosan, derived from chitin, is present in large quantities of crustacean waste. This biomass can be converted into value-added products with applications in energy, fuel, chemicals and materials manufacturing. The many reported applications of this polymer can be attributed to its unique properties, such as biocompatibility, chemical versatility, biodegradability and low toxicity. Cost effective water filters which decontaminate water by removal of specific impurities and microbes are in great demand. To address this need, the development of ion exchange resins using environmentally friendly, renewable materials such as biopolymers as solid supports was evaluated. The identification and remediation of perchlorate contaminated water using an easy, inexpensive method has come under the spotlight recently. Similarly, the use of a low cost perchlorate selective solid phase extraction (SPE) cartridge that can be rapidly employed in the field is desirable. Chitosan based SPE coupled with colorimetric analytical methods showed promise as a renewable anion exchange support for perchlorate analysis or removal. The polymers displayed perchlorate retention comparable to the commercial standard whereby the quaternized iron loaded polymer TMC-Fe(III) displayed the best activity.     

以淀粉为原料的化工制品

综述了以淀粉为原料而得到的多种化学品的性质和应用。淀粉来自可更新资源，具有良好的可获得性，而且价格低廉，因此某些以淀粉为原料所得到的化学品与来自其他资源的化学品(例如石油化学品等)相比，具有较多的优越性。重点介绍的这类化学品有：表面活性剂、超强吸水剂、可生物降解塑料、絮凝剂和粘结剂等。     

Recent developments in biopolymers

Society has been reaping the benefits of industrial polymers for a long time. Polymers have entered every market in a very influential manner, from the packaging industry to the construction business. The very properties that made polymers commercially viable are posing great environmental problems for our future generations. Also, the starting material for most of the commercial polymers is crude oil. Thus, environmental issues coupled with decreasing crude oil reserves have forced the polymer industry to find new sources. These problems having been taken into consideration, biopolymers have emerged as a promising field. This paper takes into consideration the sources of renewable materials, such as starch, lignocellulosic biomass, vegetable oils, proteins, etc.; the synthesis of polymers such as polylactic acid and monomers such as furfural, ethane, propanediol, etc., from renewable materials; and the recent developments in this field. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Treatments of protein for biopolymer production in view of processability and physical properties: A review

The development of bio‐based polymers from proteins has gained attention for their large availability and renewable and biodegradable nature. However, protein‐based plastics have limited commercial applications because of several drawbacks, such as poor processability, brittleness, moisture sensitivity, and inferior mechanical and thermal properties. Extensive studies have been conducted to solve or ameliorate these issues by pretreatment or modification of proteins or protein‐derived biopolymers before or during wet processing or dry processing at elevated temperatures. This review provides an overview of research efforts conducted in the area of physical and chemical treatment of proteins to achieve better processability, mechanical properties, and other physical performance based on a literature review in this subject. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43351.     

Unique adhesive properties of pressure sensitive adhesives from plant oils

We report novel insights into the adhesive performance of bio-based pressure sensitive adhesives (PSAs). Three different homopolymers based on renewable fatty acid methyl esters were characterized in terms of their mechanical and adhesive properties. The polymers display the typical dependence of adhesive properties on molecular weight and degree of crosslinking, as quantified by shear modulus, tack and peel measurements. The absolute values of characteristic adhesion parameters are in the range of commercially available petrochemical PSAs. Curing of applied PSA films at elevated temperature results in a pronounced maximum in tack and peel strength at a critical curing time, which corresponds to a change from cohesive to adhesive failure. Thus, demand-oriented tailoring of adhesive properties can be achieved via an appropriate choice of curing time. Moreover, these bio-based adhesives offer improved adhesion on hydrophobic substrates and high water-resistance without any whitening, thus rendering them an attractive alternative to conventional petroleum-based products. These peculiar features are attributed to the high hydrophobicity of the used monomers.     

Chitinous polymers: extraction from fungal sources,characterization and processing towards value-added applications

Chitin, chitosan and their complexes with β-glucan (chitin–glucan complex, CGC, and chitosan–glucan complex, ChGC) are value-added polysaccharides extracted from the cell-walls of many fungi. Commercial chitin and its deacetylated form, chitosan, are currently obtained from marine waste material, mostly animal sources (crustaceans and marine invertebrates), through harsh chemical procedures that have low reproducibility due to the variability of the composition of the sources and their seasonal character. These disadvantages are overcome by using fungi as sources of chitinous polymers. The extraction of chitin/chitosan from fungi cell-walls has the great advantage of yielding products with stable composition and properties, using simpler procedures, with the added benefit of also generating CGC and ChGC, two copolymers that combine the proven properties of chitin/chitosan with those of β-glucans. Over the last decades, fungal chitinous polymers have been the focus of extensive research that included optimization of the cultivation conditions of a wide range of species and the development of optimized extraction, purification and characterization techniques, as well as the demonstration of the biopolymers' biological properties, which include immunomodulatory, anticancer, antioxidant and antimicrobial activity. Given these properties, several attempts were made to develop applications for them in areas ranging from biomedicine and pharmaceuticals to food and agriculture. Despite their wide range of proven functional properties that include the ability to form different polymeric structures, as well as biological activity, fungal chitinous biopolymers are still underexplored. Nevertheless, these biopolymers hold great potential for development into valuable products or applications that are surely worth further investigation. © 2019 Society of Chemical Industry     

The contribution of bisfurfurylamine to the development and properties of polyureas

Polyureas are versatile polymers with diversified properties dependent on their chemical composition. Furan diamines can be interesting monomers for such materials because of their renewable character and ready availability from furfural, but they have not been extensively studied. The synthesis of furfurylamine‐based diamine and its condensation with an aliphatic and an aromatic diisocyanate to generate polyureas are described here together with the structure and properties of the ensuing materials. The thermoplastic features of both polymers were exploited through hot pressing of their respective powders, indicating the versatile properties of these polyureas based on a renewable comonomer. © 2020 Society of Chemical Industry     

Soy-based adhesives for wood-bonding – a review

Over recent years, the interest in bio-adhesives, including soy-based adhesives, has increased rapidly. Among natural renewable resources suitable for industrial use, soy is a reasonable choice due to its high production volume and the small use of soy meal-based products for human food consumption. Soy flour can be an ideal raw material for the manufacturing of wood adhesives due to its low cost, high protein content and easy processing. There are also more concentrated forms of soy proteins, i.e. concentrates and isolates, which are also suitable raw materials for adhesive production except that their prices are higher. Extensive research has been carried out on improving the cohesive properties, especially water resistance, of soy-based adhesives. However, there is insufficient experimental data available for understanding the influences of modification methods on the structure of soy proteins and therefore for understanding the influences of structural changes on the adhesion. In this paper, some experimental techniques are proposed to be used for analysing soy-based adhesives to enable better understanding of those factors and improve future development. This review of soy-based adhesives is made with the focus on soy proteins’ chemical composition, soy protein product types (raw materials for adhesive production), modification methods for improving the adhesive properties of soy-based adhesives, and commercial soy-based adhesives.     

Polyhydroxyalkanoates: biodegradable polymers with a range of applications

Increased and accelerated global economic activities over the past century have led to interlinked problems that require urgent attention. The current patterns of production and consumption have raised serious concerns. In this context, greater emphasis has been put on the concept of sustainable economic systems that rely on technologies based on and supporting renewable sources of energy and materials. Average UK households produce around 3.2 million tonnes of packaging waste annually whereas 150 million tonnes of packaging waste is generated annually by industries in the UK. Hence, the development of biologically derived biodegradable polymers is one important element of the new economic development. Key among the biodegradable biopolymers is a class known as polyhydroxyalkanoates. Polyhydroxyalkanoates (PHAs) are a family of polyhydroxyesters of 3‐, 4‐, 5‐ and 6‐hydroxyalkanoic acids, produced by a variety of bacterial species under nutrient‐limiting conditions with excess carbon. These water‐insoluble storage polymers are biodegradable, exhibit thermoplastic properties and can be produced from renewable carbon sources. Thus, there has been considerable interest in the commercial exploitation of these biodegradable polyesters. In this review various applications of polyhydroxyalkanoates are discussed, covering areas such as medicine, agriculture, tissue engineering, nanocomposites, polymer blends and chiral synthesis. Overall this review shows that polyhydroxyalkanoates are a promising class of new emerging biopolymers. Copyright © 2007 Society of Chemical Industry     

木质类废弃物液化及其高效利用研究进展

木质类废弃物具有数量多、分布广、可再生等特点,采用热化学液化技术将其转变为具有反应活性的新的化学原料,能替代或部分替代化石产品制备高品质化学品。本文将不同生物质转化技术以及可利用途径进行归纳总结,回顾了近年来国内外常见的木质类废弃物液化技术如高温高压液化、快速热解液化和常压催化液化等,重点介绍了广为关注的常压催化液化及其高效利用研究现状。概述了不同的液化剂和催化剂所得液化物的性质及所制备胶黏剂、聚氨酯材料等高附加值生物质基树脂材料的性能。指出木质类生物质液化过程只有朝着低成本、绿色、高效反应方向发展,才有可能向大规模工业化转化。作者结合自己的科研实践,提出该领域目前存在的一些问题以及解决途径的建议,对液化生物质基高分子材料的产业化应用提出展望。     

Polyurethanes from vegetable oils and applications: a review

Among the various polymers, polyurethanes are likely the most versatile specialty polymers. These polymers are widely used in many applications such as foams, coatings, insulations, adhesives, paints and upholstery. Similar to many polymers, polyurethanes relies on petrochemicals as raw materials for its major components. Indeed, nowadays many researches have focused to replace petroleum-based resources with renewable ones to improve polyurethanes sustainability. Polyurethanes are synthesized by polymerization reactions between isocyanates and polyols. Only a few isocyanates are commonly used in polyurethane industries, while a variety of polyols are available. Renewable materials such as vegetable oils are promising raw materials for the manufacture of polyurethane components such as polyols. Vegetable oils are triglycerides which are the esterification product of glycerol with three fatty acids. Several highly reactive sites including carbon-carbon double bond, allylic position and ester group in triglycerides and fatty acids open the opportunities for various chemical modifications for new polyol with different structures and functionalities. Different methods such as are epoxidation, ozonolysis, hydroformylation and metathesis have been widely studied to synthesise bio-polyol from vegetable oil for new polyurethanes, which depend on triglyceride and isocyanate reagents used. The incorporation of a vegetable oil moiety can enhance thermal stability and mechanical strength of polyurethanes. Similar to bio-polyol, the development of renewable resource based bio-isocyanates is also gained attention to produce entirely bio-polyurethanes. This article comprehensively reviews recent developments in the preparation of renewable resource based polyols and isocyanates for producing polyurethanes and applications.