Bio-based Amines Research Articles

Synthesis of bio-based polyimine networks with flame-retardancy, acid-degradablility, and reprocessability

Conventional thermosetting materials lack of reprocessability, acid-degradability, and fire-safety, which limit the further popularization and application of materials. In this study, a hexasubstituted cyclotriphosphazene (HVP) was synthesized from abundant renewable vanillin, and then combined with two bio-based amines (castor oil polyamine and furan-derived diamine) to establish polyimine networks through a condensation reaction between amino groups and aldehyde groups. Five bio-based polyimine thermoset networks (FA-0, FA-25, FA-50, FA-75, and FA-100) were prepared with an ammonia-formaldehyde ratio of 1:1, and varying the ratio of the two bio-based amines allowed for regulating the final mechanical properties (from tough plastic-like to hard plastic-like) and flame resistance of the materials. Among the five experimental samples, FA-100 exhibited the best physical properties stress and Tg of 28.47 MPa and 63.8 °C, respectively. FA-100 networks also showed the best flame retardant properties (LOI, 28.8 vol/%). Furthermore, due to the dynamic imine bonds in the polymer network, the material could be recycled under hot pressing conditions (120 °C and 15 MPa). Meanwhile, the monomer HVP could be recovered under mild acidic circumstances. These thermosetting polyimine networks provide a new avenue for the development of multifunctional bio-based polymer materials for practical applications.

Isocyanate-free urethanediol itaconates as biobased liquid monomers in photopolymerization-based 3D printing

Nowadays, most of the commercial resins for VP are composed of (meth)acrylated urethanes, as they are cheap and provide good mechanical properties to the thermosets produced by their photocuring. However, such urethanes are still produced using toxic and polluting isocyanates, though alternative pathways exploiting cyclic carbonates and biobased amines are arising. Unfortunately, the use of biobased amines and carbonates to produce (meth)acrylate urethanes often leads to the formation of solid products that display poor solubility in the liquid components of photocurable resins. In this work, we describe the synthesis of fully biobased diurethanediols using a biobased diamine and bioderived carbonates functionalized with itaconic acid moieties that are liquid at room temperature and that can be efficiently formulated with (meth)acrylic and itaconic acid-based formulations for VP leading to 3D printed materials with good mechanical properties, comparable to those of commercially available non-biobased alternatives. In fact, depending on the resin formulations, the addition of diurethanediols diitaconates led to the obtainment of 3D printed materials with elastic moduli as high as 1 GPa, and tensile strengths over 30 MPa, and biobased contents as high as 90 wt.%. These products may serve as candidates for the replacement of isocyanate-based components with the aim of increasing the sustainability of resins’ manufacturing for VP.

Fabrication of Eco-friendly Sustainable Superhydrophobic and Anticorrosive Coatings from Acrylated Soybean Oil and Biobased Amine by the Aza-Michael Reaction

Fabrication of Eco-friendly Sustainable Superhydrophobic and Anticorrosive Coatings from Acrylated Soybean Oil and Biobased Amine by the Aza-Michael Reaction

Bio-based amine curing agents prepared from lignin by ring-opening functionalization with cyclic aza-silanes and their curing kinetics investigated for aliphatic and aromatic epoxy species

Bio-based epoxy curing agents from lignin was synthesized by ring-opening reactions of cyclic aza-silane species to obtain lignin-based curing agents with amine hydroxyl equivalent weights up to 68 g/eq. Its cure kinetics was investigated by differential scanning calorimetry in which two representative aromatic and aliphatic epoxy species were employed being diglycidyl ether bisphenol F (DGEBF) and epoxidized soybean oil (ESBO). Utilizing Borchardt and Daniels' method to obtain cure kinetic parameters, the activation energies, Ea, were determined to 101 ± 3 kJ/mol and 71 ± 7 kJ/mol and pre-exponential factors, ln(Z), to 27.6 ± 0.9 s−1 and 13.3 ± 1.7 s−1 respectively for DGEBF and ESBO. The higher pre-exponential factor for DGEBF was attributed to π-π stacking interactions between the aromatic components resulting in overall faster cure kinetics of aromatic-based epoxy species. The lignin-based curing agent retained antioxidative properties which in cured DGEBF thermosets could act as an anti-corrosive agent. This enables the preparation of coatings without the need for leachable additive antioxidants.

Recent Advances in the Efficient Synthesis of Useful Amines from Biomass-Based Furan Compounds and Their Derivatives over Heterogeneous Catalysts

Bio-based furanic oxygenates represent a well-known class of lignocellulosic biomass-derived platform molecules. In the presence of H2 and different nitrogen sources, these versatile building blocks can be transformed into valuable amine compounds via reductive amination or hydrogen-borrowing amination mechanisms, yet they still face many challenges due to the co-existence of many side-reactions, such as direct hydrogenation, polymerization and cyclization. Hence, catalysts with specific structures and functions are required to achieve satisfactory yields of target amines. In recent years, heterogeneous catalytic synthesis of amines from bio-based furanic oxygenates has received extensive attention. In this review, we summarize and discuss the recent significant progress in the generation of useful amines from bio-based furanic oxygenates with H2 and different nitrogen sources over heterogeneous catalysts, according to various raw materials and reaction pathways. The key factors affecting catalytic performances, such as active metals, supports, promoters, reaction solvents and conditions, as well as the possible reaction routes and catalytic reaction mechanisms are studied and discussed in depth. Special attention is paid to the structure–activity relationship, which would be helpful for the development of more efficient and stable heterogeneous catalysts. Moreover, the future research direction and development trend of the efficient synthesis for bio-based amines are prospected.

Synthesis, Curing and Thermal Behavior of Amine Hardeners from Potentially Renewable Sources.

Research into bio-based epoxy resins has intensified in recent decades. Here, it is of great importance to use raw materials whose use does not compete with food production. In addition, the performance of the newly developed materials should be comparable to that of conventional products. Possible starting materials are lignin degradation products, such as vanillin and syringaldehyde, for which new synthesis routes to the desired products must be found and their properties determined. In this article, the first synthesis of two amine hardeners, starting with vanillin and syringaldehyde, using the Smiles rearrangement reaction is reported. The amine hardeners were mixed with bisphenol A diglycidyl ether, and the curing was compared to isophorone diamine, 4-4'-diaminodiphenyl sulfone, and 4-Aminonbenzylamine by means of differential scanning calorimetry. It was found that the two amines prepared are cold-curing. As TG-MS studies showed, the thermal stability of at least one of the polymers prepared with the potentially bio-based amines is comparable to that of the polymer prepared with isophorone diamine, and similar degradation products are formed during pyrolysis.

Synthesis of biobased amines via Pd-catalysed telomerisation of the renewable β-myrcene in a water/ethanol multiphase system: catalyst recycling enabled by a self-separating product phase

A recycling concept for the palladium-catalyzed amino-telomerization of the renewable β-myrcene was established via self-separating products in an aqueous multiphase system.

Synthesis and characterization of 1 K waterborne non-isocyanate polyurethane epoxy hybrid coating

Non-isocyanate polyurethanes (NIPU) attract more attention these days due to the increasing environmental concerns from the traditional polyurethanes that involve isocyanates in the synthesis. Herein we prepared a novel one-package (1 K) waterborne non-isocyanate polyurethane in this study. A series of 1 K waterborne epoxy hybrid coatings were synthesized from bio-based amine, cyclic carbonate, internal emulsifier, and epoxy resin. Different formulations of the 1 K waterborne NIPU epoxy hybrid coatings were designed including different ratios of soft and hard segments, different urethane contents, and different functionalities and structures of the hybridized epoxy. The chemical structure of the NIPU polymers was analyzed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The thermal stability and mechanical property of the 1 K waterborne NIPU coatings were investigated by thermogravimetric analysis and tensile tests, respectively. One glass transition temperature studied by differential scanning calorimetry was found for each coating which demonstrated that the soft segments and the hard segments were mixed well in the 1 K waterborne NIPU coating systems. The coatings with different formulations can achieve a broad range of thermal and mechanical properties. In addition, the general coating properties, such as hardness, adhesion, and chemical resistance, were evaluated to demonstrate the practical application of the 1 K waterborne NIPU in coatings.

Diamine derivatives of dimerized fatty acids and bio-based polyether polyol as sustainable platforms for the synthesis of non-isocyanate polyurethanes

A series of environmentally friendly non-isocyanate polyurethanes (NIPUs) were successfully prepared via the polyaddition reaction of bio-based polyether polyol-based cyclic carbonate with diamine derivative of dimerized fatty acids. The syntheses of NIPUs were realized by the three-step method in the absence of toxic solvents and, importantly, the process of carbonation did not require the use of elevated pressure. The effect of using various types of bio-based amines, [amine]/[cyclic carbonate] molar ratio as well as different reaction temperatures on the chemical structure and thermal properties were widely investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), respectively. The Gaussian deconvolution technique was used to decompose the carbonyl region (-CO) of three peaks in various samples. It was found that the molar ratio of substrates and curing temperature have an effect on the distribution of free and H-bonded carbonyl groups as well as carbonyl groups from cyclic carbonates in the chemical structure of the prepared compounds. On this basis, the role of hydrogen bonds in the chemical structure of NIPU on selected sample properties was determined. Moreover, the impact of water during 6 months of immersion on the polymer networks was examined.

Mechanistic Insight into Selective Deoxygenation of l-Lysine to Produce Biobased Amines

The shift in consumer preference toward eco-friendly plastic products is driving the overall bioplastics and biopolymers market. As such, there is a strong demand for innovative processes that prod...

A Shortcut Route to Close Nitrogen Cycle: Bio-Based Amines Production via Selective Deoxygenation of Chitin Monomers over Ru/C in Acidic Solutions.

SummaryChitin, a long-chain polymer of N-acetyl-D-glucosamine (NAG) and the most abundant natural nitrogen-containing organic material in the world, is far under-utilized than other biomass resources. Herein, we demonstrate a highly efficient deoxygenation process to convert chitin monomer, i.e., NAG, into various amines, which are the ubiquitous platform chemicals in chemical industry. In the presence of H2 and Ru/C catalyst, the oxygen atoms in the glucosamine molecules are removed in the form of H2O and/or CO/CO2, whereas CO is hydrogenated to CH4. By optimizing the reaction conditions, ∼50% yield of various amines was obtained via the selective deoxygenation of NAG. The reaction mechanism has been proposed. These findings not only promote shell biorefinery in green chemistry and fishery industry but also provide chemicals for material science, resulting in expanding cooperation in new areas such as clean energy, energy conservation, environment protection, and infrastructure.

Synthesis of Pluri-Functional Amine Hardeners from Bio-Based Aromatic Aldehydes for Epoxy Amine Thermosets.

Most of the current amine hardeners are petro-sourced and only a few studies have focused on the research of bio-based substitutes. Hence, in an eco-friendly context, our team proposed the design of bio-based amine monomers with aromatic structures. This work described the use of the reductive amination with imine intermediate in order to obtain bio-based pluri-functional amines exhibiting low viscosity. The effect of the nature of initial aldehyde reactant on the hardener properties was studied, as well as the reaction conditions. Then, these pluri-functional amines were added to petro-sourced (diglycidyl ether of bisphenol A, DGEBA) or bio-based (diglycidyl ether of vanillin alcohol, DGEVA) epoxy monomers to form thermosets by step growth polymerization. Due to their low viscosity, the epoxy-amine mixtures were easily homogenized and cured more rapidly compared to the use of more viscous hardeners (<0.6 Pa s at 22 °C). After curing, the thermo-mechanical properties of the epoxy thermosets were determined and compared. The isophthalatetetramine (IPTA) hardener, with a higher number of amine active H, led to thermosets with higher thermo-mechanical properties (glass transition temperatures (Tg and Tα) were around 95 °C for DGEBA-based thermosets against 60 °C for DGEVA-based thermosets) than materials from benzylamine (BDA) or furfurylamine (FDA) that contained less active hydrogens (Tg and Tα around 77 °C for DGEBA-based thermosets and Tg and Tα around 45 °C for DGEVA-based thermosets). By comparing to industrial hardener references, IPTA possesses six active hydrogens which obtain high cross-linked systems, similar to industrial references, and longer molecular length due to the presence of two alkyl chains, leading respectively to high mechanical strength with lower Tg.

Divanillin-Based Aromatic Amines: Synthesis and Use as Curing Agents for Fully Vanillin-Based Epoxy Thermosets.

Bio-based aromatic diamines from vanillin substrate were successfully synthesized and characterized. These amines, i.e., methylated divanillylamine (MDVA) and 3,4-dimethoxydianiline (DMAN), were then tested as curing agents for the design of bio-based epoxy thermosets. The epoxy thermosets obtained from these novel vanillin-based amines exhibited promising thermomechanical properties in terms of glass transition temperature and char residue.

Synthesis of biobased reactive hydroxyl amines by amination reaction of cardanol-based epoxy monomers

Most of the current amines are issued from petrochemical resources and only a few of them are derived from biomass. Hence, there are increasing expectations for bio-based amines, particularly for aromatic ones. We have designed and synthesized new bio-based amines containing aromatic moieties from cardanol, an aromatic non-edible co-product from agri-food industry of cashew nut. We used green amination reaction of epoxy monomers with ammonia under microwave irradiations, from two commercial epoxidized cardanol monomers with different epoxy functions: NC-514 and GX-2551 (Cashew, nutshell liq., polymer with epichlorohydrin). We studied the efficiency of our amination route onto both glycidyl and epoxy functions at the middle of the chain and the reactivity of synthesized amines toward ring opening of epoxy function. The synthesized bio-based amines were further evaluated as curing agents for epoxy resins. The thermo-mechanical properties of final bio-based thermosets synthesized therefrom are almost similar (Tg = 51 °C, Td5% = 332 °C and Tα = 64 °C for T-NC thermoset, Tg = 58 °C, Td5% = 340 °C and Tα = 78 °C for T-GX thermoset). Moreover, another aim of this study was to reduce the viscosity of hardeners compared to DHAVA hardener (400 000 mPa s at 50 °C), which was synthesized in previous work. Lower viscosities were observed in the case of cardanol-based hardener (362 000 and 33 000 mPa s at 50 °C for respectively NC-A and GX-A hardener).

Synthesis of fully bio-based and solvent free non-isocyanate poly (ester amide/urethane) networks with improved thermal stability on the basis of vegetable oils

The purpose of this study is to synthesize non-isocyanate poly (ester amide/urethane) networks, based entirely on vegetable oil through a green method, i.e., without solvent and having any rigid and aromatic structures to improve their thermal stability. For this purpose, first, three amines were synthesized from castor oil and oleic acid. Second, carbonated sunflower oil (CSFO) was obtained by reaction of epoxidized sunflower oil with CO2 at atmospheric pressure. In the final step, CSFO easily reacted with bio-based amines by melt-blending without catalyst to give corresponding non-isocyanate polyurethane (NIPU) networks. The Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) techniques were applied to characterize the structural, thermal and physical features of NIPU networks. In addition, to determine the environmental stability the water absorption amount and the degradation percentage were calculated in the deionized water and phosphate saline buffer, respectively. These NIPU networks showed an excellent thermal stability (T5 wt% between 323 and 386 °C), low water absorption and degradation (4–10 and 1.04–1.40 wt% respectively). The results show the potential of this environmentally friendly strategy for preparing bio-based NIPU for high performances. Furthermore, the presence of an aliphatic ester group and their biodegradability nature may also make them proper for biological and/or biomedical applications.

Low-Temperature Reductive Aminolysis of Carbohydrates to Diamines and Aminoalcohols by Heterogeneous Catalysis.

Short amines, such as ethanolamines and ethylenediamines, are important compounds in today's bulk and fine chemicals industry. Unfortunately, current industrial manufacture of these chemicals relies on fossil resources and requires rigorous safety measures when handling explosive or toxic intermediates. Inspired by the elegant working mechanism of aldolase enzymes, a novel heterogeneously catalyzed process-reductive aminolysis-was developed for the efficient production of short amines from carbohydrates at low temperature. High-value bio-based amines containing a bio-derived C2 carbon backbone were synthesized in one step with yields up to 87 C%, in the absence of a solvent and at a temperature below 405 K. A wide variety of available primary and secondary alkyl- and alkanolamines can be reacted with the carbohydrate to form the corresponding C2-diamine. The presented reductive aminolysis is therefore a promising strategy for sustainable synthesis of short, acyclic, bio-based amines.

Influence of synthetic and bio-based amine curing agents on properties of solventless epoxy varnishes and coatings with carbon nanofillers

Abstract Solventless epoxy varnishes and coatings were prepared using carbon nanotubes (CNT) and/or graphene (GNP) dispersions in a Bisphenol F-type epoxy resin, synthetic hardeners [tetraethylenepentamine, poly(oxyethylene)diamine, isophoronediamine, m-xylylenediamine] or bio-based amine hardener (Cardanol-based phenalkamine, abbreviationabbreviation: PAA). Room temperature cured coatings, containing 0.35 wt.% of CNT predispersed in PAA, showed outstanding combination of optical (i.e. high gloss and transparency, low haze in humid conditions) and electrostatic dissipative properties (surface resistivity ca. 5.5 × 10 7 Ω) in relation to the samples containing carbon nanofiller(s) dispersion in the epoxy resin or a synthetic amine. PAA-based coatings with the carbon nanofillers exhibited increased cupping resistance (+20% for samples with CNT) as well as high hardness and excellent adhesion to a glass substrate. The carbon nanofillers addition influenced on curing process and glass transition temperature (monitored using differential scanning calorimetry technique) of the epoxy varnishes and coatings as well.

Enhancement of anti-corrosive performances of cardanol based amine functional benzoxazine resin by copolymerizing with epoxy resins

Abstract The bio-based amine functional benzoxazine (Bnz) resin was synthesized from cardanol, N , N' -Bis(2-aminoethyl)ethane-1,2-diamine and paraformaldehyde by the Mannich condensation reaction. The additional amine functionality in Bnz resin was introduced by using multi functional amine ( N , N' -Bis(2-aminoethyl)ethane-1,2-diamine) to react with monofunctional cardanol. The synthesized amine functional Bnz resin was chemically analyzed for amine value by volumetric titration method. The Fourier Transform Infrared spectroscopy (FTIR) and 1 H-Nuclear Magnetic Resonance ( 1 H NMR) spectroscopy used to illustrate the structure of amine functional Bnz resin. The synthesized Bnz resin was copolymerized with conventional epoxy resins to prepare Poly(Benzoxazine-co-Epoxy) coatings for anti-corrosive application. The network formation of Bnz and epoxy resins was monitor by FTIR analysis. The Poly(Benzoxazine-co-Epoxy) coatings have shown good mechanical, chemical, and solvent resistance properties as compared to the crosslinked Polybenzoxazine coating. Further, gel content and water absorption of Poly(Benzoxazine-co-Epoxy) and Polybenzoxazine coatings were also studied. The cured coatings were evaluated for thermal behavior by thermogravimetric analysis (TGA). The corrosion resistance properties of coatings were investigated by salt spray and electrochemical analysis.

Bio-based amines through sustainable heterogeneous catalysis

Heterogeneous catalysis offers a sustainable toolbox for the synthesis of a wide variety of biomass-derived amines.

Biobased Amines: From Synthesis to Polymers; Present and Future.

Amines are key intermediates in the chemical industry due to their nucleophilic characteristic which confers a high reactivity to them. Thus, they are key monomers for the synthesis of polyamides, polyureas, polyepoxydes, which are all of growing interest in automotive, aerospace, building, or health applications. Despite a growing interest for biobased monomers and polymers, and particularly polyamides, it should be noticed that very few natural amines are available. Actually, there is only chitosan and poly(lysine). In this review we present both fundamental and applied research on the synthesis of biobased primary and secondary amines with current available biobased resources. Their use is described as a building block for material chemistry. Hence, we first recall some background on the synthesis of amines, including the reactivity of amines. Second we focus on the synthesis of biobased amines from all sorts of biomass, from carbohydrate, terpenes, or oleochemical sources. Third, because they need optimization and technological developments, we discuss some examples of their use for the creation of biobased polymers. We conclude with the future of the synthesis of biobased amines and their use in different applications.