Analysis of the influence of cardanol content on the properties of phenol-cardanol-formaldehyde novolac resins

The influence of cardanol content on the molecular-weight distribution and curing kinetics of phenol-cardanol-formaldehyde novolac oligomers is investigated. It is shown that, depending on the cardanol content, the resulting oligomers can be used as components in glues and sealants of different purposes.     

Plasticizer for poly(vinyl chloride) from cardanol as a renewable resource material

The present work is aimed to the preliminary analysis of the applicability of cardanol derivatives as renewable plasticizers for soft PVC. Two different plasticizers were studied, obtained by esterification of the cardanol hydroxyl group (cardanol acetate) and further epoxidation of the side chain double bonds (epoxidated cardanol acetate). Differential Scanning Calorimetry (DSC) was used to study the miscibility between PVC and cardanol derived plasticizers. The miscibility was correlated to the chemical structure of plasticizer by means of the Hansen solubility parameter analysis. Results obtained indicated that esterification of cardanol yields a partial miscibility with PVC, whereas esterification and subsequent epoxidation yield a complete miscibility with PVC. Therefore cardanol acetate, obtained by solvent-free esterification of cardanol, was used as a secondary plasticizer of PVC. Mechanical and rheological analysis showed that the cardanol acetate can partially replace DEHP in PVC formulation.     

Physicochemical properties of series of cardanol polyoxyethylene ether carboxylates with different ethoxylation unit at the interface

Series of cardanol polyoxyethylene ether carboxylates were synthesized with biomass cardanol as material to study their physicochemical properties at the interface. The surface tensions of the cardanol nonionic-anionic surfactants were measured at 25?°C and the thermodynamic parameters of adsorption were also calculated. The surface activity and thermodynamic properties of the cardanol nonionic-anionic surfactants were correlated to their chemical structures. With increasing of the number of the ethoxylation unit in the hydrophilic group, a decrease in adsorption efficiency and an increase in surface tension at critical micelle concentration and thermodynamic free energy of adsoption were observed and were attributed to a decrease in adsorption of the cardanol nonionic-anionic surfactants at the interface. Series of the cardanol nonionic-anionic surfactants have good wettability and foaming property. The foaming capacity and the foaming stability of the solution of the cardanol nonionic-anionic surfactants increase by decreasing in the ethoxylation unit and by increasing the double bond of the hydrophobic group. The physicochemical properties of the cardanol nonionic-anionic surfactants at the interface are correlated to the chemical structures of the investigated surfactants, and there is the synergy effect between the nonionic hydrophilic group and the anionic hydrophilic group at the interface.     

具有光引发活性腰果酚衍生物的合成及其UV固化

以腰果酚与4-溴甲基二苯甲酮为原料,合成了具有光引发活性的腰果酚衍生物,收率86%。 该衍生物的光引发活性优于普通的二苯甲酮。 在不加其它光引发剂的情况下,UV光照30 s该液体衍生物即可固化。 该衍生物与腰果酚不同比例的混合物,也可进行UV 固化,腰果酚含量越高,所需固化时间越长。膜的硬度为3H-5H,且具有较好的耐溶剂与耐酸碱性能,可望用于防腐漆中。     

腰果酚的紫外光固化机理和固化膜性能

研究了腰果酚在无光引发剂条件下的紫外光固化反应,并用IR、UV、元素分析、GPC等分析手段分析了腰果酚的紫外光固化机理及其固化膜性能。结果表明:在紫外光辐照下,腰果酚通过侧链发生氧化聚合反应,和酚羟基的邻对位失去质子形成的自由基引起的苯环缩合反应,最终形成体型高聚物。腰果酚的紫外光固化膜的常规物理机械性能、抗溶剂性、耐化学介质腐蚀性、热稳定性和抗紫外线性能均优于腰果酚醛缩聚物(PC)涂膜。     

A study on the kinetics of condensation reaction of phenol‐modified cardanol–formaldehyde resin

Phenol‐modified cardanol–formaldehyde novolac resins have been synthesized using equal proportions of phenol and cardanol. To this mixture of phenol and cardanol, 0.6 and 0.8 mol of formaldehyde were added separately, under acidic conditions, at five different temperatures ranging between 80 and 120°C with an interval of 10°C. This was carried out for a maximum period of 6 h. The free formaldehyde and free phenol contents were determined at regular time intervals to check the completion of the reaction. The synthesized novolacs have been studied by infrared spectroscopic analysis (FT‐IR). The reaction between cardanol, phenol, and formaldehyde was found to follow a second‐order rate kinetics. The overall rate constant (k) increased with the increase of temperature. Based on the value of rate constants, various other parameters such as activation energy (E_a), change in enthalpy (Δ H) and entropy (Δ S), and free energy change (Δ G) of the reaction were also evaluated. It was found that the condensation reaction of phenol and cardanol with formaldehyde was nonspontaneous and irreversible. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 380–389, 2010     

Enzymatic modification of lignocellulosic substances for the production of fiberboards

The object of the research is the development of enzyme systems for the enzymatic modification of wood fiber materials as well as fiber materials from annual plants for the production of glue-free fiberboards. The project is aimed first at the process development for the enzymatic modification and second at the development of cellulase/hemicellulase complexes on the basis of stillage as a substrate and inducer for the enzymatic modification. The results demonstrate that it is possible to substitute synthetic resins by means of activation and biocatalytic cross-linking of fibers with hydrolytic enzyme systems, in particular, for the production of medium-density fiberboards. The article is published in the original.     

Horseradish Peroxidase Catalyzed Synthesis of Polycardanol Microcapsules

Polymers synthesized from naturally derived monomers are valuable since they decrease the reliance on petroleum based feed stocks. Cashew nut shell oil (CNSL) is a side-product from processing of edible Cashew nuts of Annacardium occidentale. One of the major components of CNSL is cardanol, which is a phenol derivative having an unsaturated pentadecyl substituent in the ‘meta’ position with varying amount of unsaturation (no double bonds to three double bonds). The substituent in the meta position can also be hydrogenated to yield completely saturated hydrogenated cardanol. Cardanol can be utilized to stabilize the dispersions of oil in water and vice versa since it displays amphiphilic behavior owing to the phenolic head and the C15 aliphatic tail. Here we report the horseradish peroxidase (HRP) catalyzed polymerization of cardanol at oil water interface to obtain polycardanol microcapsules. A synthetic analogue of hydrogenated cardanol, 3-pentadecylphenol (3PDP), was also oxidatively polymerized at the oil-water interface to obtain Poly(3-pentadecylphenol) microcapsules.     

Amphiphilic antioxidants from "cashew nut shell liquid" (CNSL) waste

Hydrogenated cardanol and cardols, contained in industrial grade cardanol oil and obtained by distillation of the raw "cashew nut shell liquid" (CNSL), are easily transformed into efficient 4-thiaflavane antioxidants bearing a long alkyl chain on A ring and a catechol group on B ring.     

Adhesive binders for PCM components of a cellular structure

The main physical, mechanical, and rheological properties of VSK-14-2m and VSK-14-3 moltentype epoxy adhesive binders are described. The optimal temperature range for the processing of these binders for the synthesis of high-quality adhesive prepregs reinforced with glass and coal fillers is shown.     

Cyanate esters based on cardanol modified-phenol-formaldehyde resins: Syntheses and thermal characteristics

Cardanol incorporated-phenol-formaldehyde novolac resins were synthesized by acid and base catalyzed reactions. The novolacs were transformed to their cyanate esters. The thermal cure characteristics of the cyanate esters depended upon the composition. The presence of cardanol proportionately facilitated the curing. The thermal characterization of the novolacs and the corresponding cured phenolic-triazine networks indicated a dedicated a detremental effect of cardanol on the thermal stability and char residue of the resins. © 1995 John Wiley & Sons, Inc.     

生物质腰果酚磺酸盐表面活性剂的合成及其乳化性能

采用发烟硫酸对生物质腰果酚进行磺化,得到腰果酚磺酸盐表面活性剂;利用红外光谱表征了产物的化学结构;分别采用悬滴法和小液滴法测定了腰果酚磺酸盐水溶液的表面张力和润湿性能,采用分水法测定了产物对液体石蜡的乳化性能,同时考察了氯化钠对乳化性能的影响.结果表明:所制备的腰果酚磺酸盐的临界胶束浓度(cmc)及γcmc分别为3.3...     

Renewable epoxidized cardanol‐based acrylate as a reactive diluent for UV‐curable resins

A novel kind of biobased monomer, epoxidized cardanol‐based acrylate (ECA), was successfully synthesized from cardanol via acrylation and epoxidization. The chemical structure was confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Then, the ECA was employed to produce UV‐curable films and coatings copolymerized with castor oil‐based polyurethane acrylate. Compared to coatings from petroleum‐based diluent hydroxyethyl acrylate‐based castor oil‐based polyurethane acrylate resins, ECA‐based biomaterials exhibited a little inferior dilution ability but overcome the drawback of high volumetric shrinkage with a special lower value. Moreover, ultimate properties of the UV‐cured biomaterials such as thermal, mechanical, coating, swelling, and hydrophobic properties were investigated. The UV‐curing behavior was investigated using real‐time IR, and the overall double bond conversion was more than 90%. This biobased UV‐curable cardanol‐based diluent shows a promise in “green + green” materials technologies.     

Bio-based polybenzoxazine composites for oil-water separation,sound absorption and corrosion resistance applications

In the present work, an attempt has been made to develop bio-based composites using cardanol and eugenol based benzoxazine matrices with bio-silica as well as natural fibrous materials (coir felt, kapok fabric, jute felt and rice husk) as reinforcements. The bio-composites developed were studied for different applications viz., dielectric, water repellent, oil-water separation, sound-absorption including corrosion resistance use. Among the bio-silica reinforced benzoxazine composites, 7 wt% bio-silica reinforced cardanol composites possesses the highest value of water contact angle (147°) and the lowest value of dielectric constant (2.0) than those of other bio-silica reinforced composites. Further, the cotton fabric was coated with cardanol and eugenol based polybenzoxazines separately, whose values of water contact angles are found to be 159° and 157° with oil-water separation efficiency as 96% and 95% respectively. Furthermore, the cardanol based benzoxazine was separately reinforced with jute felt, coir felt, kapok fabric and rice-husk. The corresponding sound absorption efficiency was found to increase in the following order, Neat polybenzoxazine < rice husk < coir felt < kapok fabric < jute felt. Data resulted from corrosion studies, it was noticed that the mild steel specimen coated with bio-based benzoxazine matrices and bio-silica reinforced benzoxazine composites coated specimens exhibit an excellent resistance to corrosion. Data resulted from different studies, it is suggested that the cardanol and eugenol based bio-composites can be considered as an effective materials for microelectronics insulation, water repellent, oil-water separation, sound absorption and corrosion resistant applications.     

DNA‐Encoded Dynamic Combinatorial Chemical Libraries

Dynamic combinatorial chemistry (DCC) explores the thermodynamic equilibrium of reversible reactions. Its application in the discovery of protein binders is largely limited by difficulties in the analysis of complex reaction mixtures. DNA‐encoded chemical library (DECL) technology allows the selection of binders from a mixture of up to billions of different compounds; however, experimental results often show low a signal‐to‐noise ratio and poor correlation between enrichment factor and binding affinity. Herein we describe the design and application of DNA‐encoded dynamic combinatorial chemical libraries (EDCCLs). Our experiments have shown that the EDCCL approach can be used not only to convert monovalent binders into high‐affinity bivalent binders, but also to cause remarkably enhanced enrichment of potent bivalent binders by driving their in situ synthesis. We also demonstrate the application of EDCCLs in DNA‐templated chemical reactions.     

Novel Synthetic Strategy for the Production of Fully Bio-Based Binders Using 2,5-Diformylfuran

In this work, resol based binders were prepared with lignin, resorcinol and the bio-based aldehydic platform chemicals 5-hydroxymethylfurfural (HMF) and 2,5-diformylfuran (DFF). In preliminary studies, the solubility and stability of DFF in aqueous-alkaline conditions was investigated. Various binders were prepared to investigate the influence of the HMF-DFF ratio and the influence of the aldehyde concentration on the molar mass, rheological properties and curing characteristics of the final binders. It is shown that significantly higher molecular weights and viscosities are obtained by using DFF instead of HMF. The properties of the final binder could also be affected by the precise choice of DFF concentration, as this resulted in higher levels of crosslinking. This work offers a novel type of fully bio-based binder that consists of non-toxic components and is therefore less hazardous than some conventional binders.     

Extraction and characterization of cellulose nanocrystals from post-consumer wood fiberboard waste

This study investigates the potential of wood wastes, specifically post-consumer fiberboards, as a new source for cellulose nanocrystals (CNC). This underused resource has currently no commercially viable way to recycle it and so the volumes of fiberboard waste are growing rapidly. A sequential chemical fractionation was used to separate the three main constituents of wood, namely cellulose, hemicelluloses and lignin, and the non-wood components present in fiberboards, such as resins and finishes (e.g. varnishes, paints, plastics, laminates, etc.). Most of the non-cellulosic components and non-wood elements were removed by an alkali treatment followed by bleaching, resulting in a cellulosic fraction which is suitable for the further isolation of CNC by an acid hydrolysis step. The intermediate and final products were characterized by chemical composition, microscopic, spectroscopic and X-ray diffraction methods. The CNC obtained from wood waste are totally devoid of traces of contaminants and possess comparable characteristics and quality to those extracted from virgin wood fibers. The results indicate that fiberboard wastes can be used as promising alternative source for nanocelluloses production.     

Nicotinamide Adenine Dinucleotide Oxidation Studies at Multiwalled Carbon Nanotube/Polymer Composite Modified Glassy Carbon Electrodes

NADH oxidation has previously been investigated at carbon nanotube surfaces, although studies into the effect of the polymer binders are needed to fully understand whether the polymer binder affects the electrochemistry. This work details NADH oxidation at glassy carbon electrodes modified with composites containing multiwalled carbon nanotubes and selected polymer binders. NADH is shown to be oxidized at a lower potential than at glassy carbon electrodes and the oxidation potential is a function of the polymer binder. Hydrophobically modified Nafion, Nafion, linear poly(ethylenimine) (LPEI), octyl‐modified LPEI, and poly(vinylpyridine) binders were studied. Experiments showed the peak current and electrochemically assessible electrode area are dependent on the polymer binder. Overall, this paper shows that polymer binders affect NADH oxidation potential at carbon nanotube modified electrodes.     

Synthesis of brominated cardanol derivatives and their effeciency as fire retardants for wood

The synthesis of a fire retardant based on bromo derivatives of cardanol was examined and the composition, structure, and fire-protective efficiency of this retardant were studied.