Epoxy resins from rosin acids: synthesis and characterization

Bio-based monomers for amide-containing sustainable polymers

The field of sustainable polymers from renewable feedstocks is a fast-reviving field after the decades-long domination of petroleum-based polymers. Amide-containing polymers exhibit a wide range of properties depending on the type of amide (primary, secondary, and tertiary), amide density, and other molecular structural parameters (co-existing groups, molecular weight, and topology). Engineering amide groups into sustainable polymers via the "monomer approach" is an industrially proven strategy, while bio-based monomers are of enormous importance to bridge the gap between renewable sources and amide-containing sustainable polymers (AmSPs). This feature article aims at conceptualizing the monomer-design philosophy behind most of the reported AmSPs and is organized by discussing di-functional monomers for step-growth polymerization, cyclic monomers for ring-opening polymerization and amide-containing monomers for chain-growth polymerization. We also give a perspective on AmSPs with respect to monomer design and performance enhancement.

Sustainable cycloaliphatic polyurethanes: from synthesis to applications

Polyurethanes (PUs) are a versatile and major polymer family, mainly produced via polyaddition between polyols and polyisocyanates. A large variety of fossil-based building blocks is commonly used to develop a wide range of macromolecular architectures with specific properties. Due to environmental concerns, legislation, rarefaction of some petrol fractions and price fluctuation, sustainable feedstocks are attracting significant attention, e.g., plastic waste and biobased resources from biomass. Consequently, various sustainable building blocks are available to develop new renewable macromolecular architectures such as aromatics, linear aliphatics and cycloaliphatics. Meanwhile, the relationship between the chemical structures of these building blocks and properties of the final PUs can be determined. For instance, aromatic building blocks are remarkable to endow materials with rigidity, hydrophobicity, fire resistance, chemical and thermal stability, whereas acyclic aliphatics endow them with oxidation and UV light resistance, flexibility and transparency. Cycloaliphatics are very interesting as they combine most of the advantages of linear aliphatic and aromatic compounds. This original and unique review presents a comprehensive overview of the synthesis of sustainable cycloaliphatic PUs using various renewable products such as biobased terpenes, carbohydrates, fatty acids and cholesterol and/or plastic waste. Herein, we summarize the chemical modification of the main sustainable cycloaliphatic feedstocks, synthesis of PUs using these building blocks and their corresponding properties and subsequently present their major applications in hot-topic fields, including building, transportation, packaging and biomedicine.

Experimental Determination and Computational Prediction of Dehydroabietic Acid Solubility in (−)-α-Pinene + (−)-β-Caryophyllene + P-Cymene System

The solubility of dehydroabietic acid in (−)-α-pinene, p-cymene, (−)-β-caryophyllene, (−)-α-pinene + p-cymene, (−)-β-caryophyllene + p-cymene and (−)-α-pinene + (−)-β-caryophyllene were determined using the laser monitoring method at atmospheric pressure. The solubility of dehydroabietic acid was positively correlated with temperature from 295.15 to 339.46 K. (−)-α-pinene, p-cymene, and (−)-β-caryophyllene were found to be suitable for the solubilization of dehydroabietic acid. In addition, the non-random two liquid (NRTL), universal quasi-chemical (UNIQUAC), modified Apelblat, modified Wilson, modified Wilson–van’t Hoff, and λh models were applied to correlate the determined solubility data. The modified Apelblat model gave the minor deviation for dehydroabietic acid in monosolvents, while the λh equation showed the best result in the binary solvents. A comparative analysis of compatibility between solutes and solvents was carried out using Hansen solubility parameters. The thermodynamic functions of Δ_solH⁰, Δ_solS⁰, Δ_solG⁰ were calculated according to the van’t Hoff equation, indicating that the dissolution was an entropy-driven heat absorption process. The Conductor-like Screening Model for Real Solvents (COSMO-RS) combined with an experimental value was applied to predict the reasonable solubility data of dehydroabietic acid in the selected solvents systems. The interaction energy of the dehydroabietic acid with the solvent was analyzed by COSMO-RS.

Rosin modified aminated mesoporous silica adsorbed tea tree oil sustained-release system for improve synergistic antibacterial and long-term antibacterial effects

Tea tree oil, a natural antibacterial compound, cannot be used effectively because of its volatile nature. In this work, a biocompatible carrier was prepared and loaded with tea tree essential oil. The carrier was prepared via the electrostatic or chemical action of aminated mesoporous silica and sodium rosin for achieving a low volatilization rate of tea tree essential oil. A synergistic antibacterial effect was observed between sodium rosin and tea tree essential oil. This method utilized the positive charge of the amino group and the condensation reaction with the carboxyl group to achieve physical and chemical interactions with sodium rosin. Fourier Transform Infrared, Brunauer-Emmet-Teller, Zeta potential, SEM, TEM, and TG were performed to characterize the structure and properties of the samples. Compared to the electrostatic effect, the chemically modified system exhibited a longer sustained release, and the sustained release curve followed the Korsmeyer-Peppas release model. Also, the antibacterial properties of the chemically modified system exhibited better minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) respectively, the MIC and MBC forE. coliwere 0.3 mg ml^-1and 0.6 mg ml^-1respectively, forS. aureuswere 0.15 mg ml^-1and 0.3 mg ml^-1respectively. More strikingly, the sample also demonstrated long-term antibacterial performance. Therefore, this work provides a new way for the delivery of volatile antibacterial drugs to achieve sustained-release and long-lasting antibacterial effects.

Polyamides containing a biorenewable aromatic monomer based on coumalate esters: from synthesis to evaluation of the thermal and mechanical properties

A new biobased alternative for terephthalic acid (TPA) in (semi-)aromatic polyamides is proposed, namely 4-carboxybenzene propionic acid (4CBPA).

Multi-Functional Cardanol Triazine Schiff Base Polyimine Additives for Self-Healing and Super-Hydrophobic Epoxy of Steel Coating

The designing of multifunctional materials in system-level efficiency is one of the main targets and a hot topic for the application of novel green or bio-based materials and structures. In this work, the chemical structure of bio-based cardanol that was derived from cashew oil was modified through a reaction with a bishydrazino-s-triazine derivative followed by condensation polymerization or reaction with terephthaldehyde to obtain a Schiff base polymer. The chemical structures of the modified cardanol-bishydrazino-s-triazine-based monomer and the Schiff base polymer were confirmed from FTIR and NMR spectroscopy analyses. The modified cardanol bishydrazino-s-triazine monomer and polymer were added with different weight ratios during the curing of the epoxy/polyamine hardener to improve the thermal, mechanical, and anti-corrosion characteristics of the epoxy coating of a steel substrate. The data elucidated that the presence of a cardanol bishydrazino-s-triazine monomer and polymer improves the thermal, mechanical, adhesion, and anti-corrosion characteristics of epoxy coatings after exposure for more than 1500 h. The presence of a cardanol- bishydrazino-s-triazine polymer more than 3 wt.% during the curing of epoxy networks produces superhydrophobic and self-healing epoxy coatings. The modification of the epoxy coating with the cardanol bishydrazino-s-triazine polymer improves the seawater contact angle by more than 150° and the adhesion strength of the epoxy coating with the steel surface.

Structure-based rational design, synthesis, crystal structure, DFT and molecular docking of 1,4-benzene dicarboxamide isomers with application as hardeners

Molecular structures of two isomers have been investigated by SXRD analysis and DFT calculations and the isomers are assessed for their antimicrobial properties and as curing agents for epoxy resins.

Property enhancement and DFT study of wood polymer composites using rosin derivatives as co-monomers

Synthesis of wood polymer composites with a polymer matrix and a reinforcing agent derived from renewable resources having satisfactory properties.

Synthesis of environmentally friendly highly dispersed magnetite nanoparticles based on rosin cationic surfactants as thin film coatings of steel

This work presents a new method to prepare monodisperse magnetite nanoparticles capping with new cationic surfactants based on rosin. Core/shell type magnetite nanoparticles were synthesized using bis-N-(3-levopimaric maleic acid adduct-2-hydroxy) propyl-triethyl ammonium chloride (LPMQA) as capping agent. Fourier transform infrared spectroscopy (FTIR) was employed to characterize the nanoparticles chemical structure. Transmittance electron microscopies (TEM) and X-ray powder diffraction (XRD) were used to examine the morphology of the modified magnetite nanoparticles. The magnetite dispersed aqueous acid solution was evaluated as an effective anticorrosion behavior of a hydrophobic surface on steel. The inhibition effect of magnetite nanoparticles on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Results obtained from both potentiodynamic polarisation and EIS measurements reveal that the magnetite nanoparticle is an effective inhibitor for the corrosion of steel in 1.0 M HCl solution. Polarization data show that magnetite nanoparticles behave as a mixed type inhibitor. The inhibition efficiencies obtained from potentiodynamic polarization and EIS methods are in good agreement.