Bio-based Resin Research Articles

Preparation of High-Toughness Lignin Phenolic Resin Biomaterials Based via Polybutylene Succinate Molecular Intercalation

Lignin has many potential applications and is a biopolymer with a three-dimensional network structure. It is composed of three phenylpropane units, p-hydroxyphenyl, guaiacyl, and syringyl, connected by ether bonds and carbon-carbon bonds, and it contains a large number of phenol or aldehyde structural units, resulting in complex lignin structures. This limits the application of lignin. To expand the application range of lignin, we prepared lignin thermoplastic phenolic resins (LPRs) by using lignin instead of phenol; these LPRs had molecular weights of up to 1917 g/mol, a molecular weight distribution of 1.451, and an O/P value of up to 2.73. Due to the complex structure of the lignin, the synthetic lignin thermoplastic phenolic resins were not very tough, which greatly affected the performance of the material. If the lignin phenolic resins were toughened, their application range would be substantially expanded. Polybutylene succinate (PBS) has excellent processability and excellent mechanical properties. The toughening effects of different PBS contents in the LPRs were investigated. PBS was found to be compatible with the LPRs, and the flexible chain segments of the small PBS molecules were embedded in the molecular chain segments of the LPRs, thus reducing the crystallinities of the LPRs. The good compatibility between the two materials promoted hydrogen bond formation between the PBS and LPRs. Rheological data showed good interfacial bonding between the materials, and the modulus of the high-melting PBS made the LPRs more damage resistant. When PBS was added at 30%, the tensile strength of the LPRs was increased by 2.8 times to 1.65 MPa, and the elongation at break increased by 31 times to 93%. This work demonstrates the potential of lignin thermoplastic phenolic resins for industrial applications and provides novel concepts for toughening biobased aromatic resins with PBS.

SLA printing of POSS-containing, bio-based composites with low dielectric constant and shape-memory function

Improving sustainability and functionality of resins is important for the development of 3D printing technologies. This work demonstrates a novel bio-based and low dielectric resin containing polyhedral oligomeric silsesquioxane (POSS) for stereolithography (SLA) printing to fabricate sensors and shape memory materials with complex geometry. Epoxidized soybean oil (ESO) and methacrylic acid are used to synthesize a biobased methacrylate resin (MESO) via a ring-opening reaction, followed by incorporation of POSS into polymer matrix. In general, the viscosity of POSS/MESO composite resins is in the range of 0.40–0.58 Pa s, making them viable for SLA printing designs. With the addition of 5 wt% POSS, POSS/MESO composites can exhibit excellent mechanical properties, including tensile strength (18.9 MPa), elongation at break (19.8%), and toughness (399.2 MJ/m3). Furthermore, these materials have a very low dielectric constant of 2.97 at 1 MHz, which is desired for microelectronic applications to overcome signal delay and energy loss. In addition, presence of permanent and reversible networks formed by MESO and POSS endows the POSS/MESO composites with good shape memory property. The application demonstrators include fabrication of flexible interdigital electrode sensors and temperature-responsive sensors. Overall, this work provides great potential opportunities to design the bio-based functional sensor with on-demand control over structures by SLA printing.

Vat Photopolymerization of Nanocellulose-Reinforced Vegetable Oil-Based Resins: Synergy in Morphology and Functionalization

With the advancement of additive manufacturing (AM) and the mass adoption of 3D printing technology, it is essential to shift focus to environmentally and economically sustainable materials. As the utilization of renewable feedstocks is quite limited in this context, the utilization of more bio-based raw materials in the ongoing development of AM represents an essential means of achieving this shift. In this work, vat photopolymerization 3D printing has been used to process vegetable oil-based (VO) resins with an ultralow concentration of 0.07 vol % nanocellulose fibrils (NFC) and crystals (NCC). The developed nanocellulose containing bio-based vat photopolymerization resin shows excellent shelf stability, enabling high-resolution printing. Compatibilization of the nanocellulose with the polymer matrix was achieved through the introduction of isocyanate or acrylate groups via reactions of acryloyl chloride (AC) and hexamethylene diisocyanate (HMDI) with cellulose surface hydroxyls. Surface functionalization results in ∼20–30% increases in interfacial adhesion and stress transfer, yielding significant improvements in mechanical performance (4× higher toughness, 2.4× higher tensile strength, and 2× higher tensile strain) in 3D-printed specimens. Fourier-transformation infrared (FTIR) spectroscopy complemented by solid-state nuclear magnetic resonance (NMR) techniques enabled a more detailed study of the chemical structure of these materials as well. Tensile performance comparison with literature data on VO-based natural fiber-reinforced resins showed that this work brought bio-based resins one step closer to competing with petroleum-based resins. The prepared VO/nanocellulose resins are promising candidates for high-performance bio-based resins derived from completely renewable feedstocks.

Tailored Biobased Resins from Acrylated Vegetable Oils for Application in Wood Coatings

The modern coating market is dominated by acrylic, polyurethane, and polyester polymer resins produced from unsustainable fossil resources. Herein, we propose the preparation of resins from biobased components to produce functional and solvent-free wood coatings with enhanced performance properties. Acrylated rapeseed, linseed, and grapeseed oils were prepared via a one-step synthesis and used as a basis for the control of resin viscosity and fatty acid content. A combination of vegetable oil acrylates was used as a matrix and the biobased monomer propoxylated glycerol triacrylate (GPT) was selected to tailor the properties of the UV crosslinked network. During polymerization, the GPT monomer induced a two-phase microstructure as indicated by an SEM analysis. The possibility of generating a tailored microstructure in the final material was examined in this study. The addition of GPT increased the storage modulus by up to five-fold, crosslink density by up to two-fold at 20 °C, and glass transition temperature by up to 10.2 °C. Pull-off adhesion tests showed a strength of 1.21 MPa. In addition, the photo-oxidation effect on samples, i.e., aging, was assessed with microhardness, sliding friction, and optical microscopy. Coatings showed a microhardness value up to 250 MPa, while a coefficient of friction (μ) was in the range of 0.21 to 0.88.

A facile strategy and mechanism to achieve biobased bismaleimide resins with high thermal-resistance and strength through copolymerizing with unique propargyl ether-functionalized allyl compound

Preparing biobased thermosetting resins with high mechanical properties and superior heat resistance is an important issue for the sustainable development and applications of high performance resins. Herein, a novel biobased allyl compound (DBB) with aryl propargyl ether groups was synthesized from renewable honokiol, which was then used to copolymerize with 4,4′-bismaleimidodiphenylmethane (BDM) to develop new biobased resins (BDM/DBB). The effects of the molar ratio of BDM to DBB on the thermal and mechanical properties were studied. Results show that all BDM/DBB resins possess both high thermal and mechanical properties. Specifically, their glass transition temperatures (Tg > 440 °C) and storage moduli (> 1.3 GPa at 400 °C) are higher than those of biobased allyl compounds modified BDM resins reported so far (SCI database); moreover, their initial thermal decomposition temperatures are about 448 °C and flexural strengths range from 106 to 117 MPa. These excellent comprehensive performances are attributed to the unique crosslinked network resulted from the complex curing mechanism of BDM/DBB, which including the copolymerization between imide groups and allyl groups as well as the additional thermal crosslinking of aryl propargyl ether. This work provides a sustainable and facile strategy to construct high performance biobased resins.

Electrospun porous carbon nanofibers derived from bio-based phenolic resins as free-standing electrodes for high-performance supercapacitors

Electrospun porous carbon nanofibers derived from bio-based phenolic resins as free-standing electrodes for high-performance supercapacitors

Biodegradable thermoset poly(lactic acid) resin containing phosphorus: Flame retardancy, mechanical properties and its soil degradation behavior

With the growing environmental awareness, poly(lactic acid) (PLA) is regarded as one of the most promising varieties of bio-based polyesters owing to its environment-friendly and biodegradable advantages. However, poor thermal stability and flammability disadvantages limit the applications of PLA. Herein, a series of biodegradable intrinsic flame-retardant thermoset PLA resins (DMMP-M4sPLA) were designed. DMMP-M4sPLA resins exhibit excellent flame retardancy, achieving UL 94 V-0 rating and limiting oxygen index (LOI) of 28.1 %–31.7 %. Meanwhile, the cured DMMP-M4sPLA resins show a high glass transition temperature and tensile strength. In addition, the resins demonstrate full degradation with no harmful degradation products. This work provides an advanced design strategy to create bio-based and biodegraded resins with superior flame retardant and mechanical performance, holding great potentials in the fields of aviation interior, automotive, etc.

Epoxy and Bio-Based Epoxy Carbon Fiber Twill Composites: Comparison of the Quasi-Static Properties.

In recent years, interest in sustainability has significantly increased in many industrial sectors. Sustainability can be achieved with both lightweight design and eco-friendly manufacturing processes. For example, concerns on the use of thermoset composite materials, with a lightweight design and a high specific strength, have arisen, since thermoset resins are not fully recyclable and are mainly petrol based. A possible solution to this issue is the replacement of the thermoset matrix with a recyclable or renewable matrix, such as bio-based resin. However, the mechanical properties of composites made with bio-based resin should be carefully experimentally assessed to guarantee a safe design and the structural integrity of the components. In this work, the quasi-static mechanical properties of composite specimens (eight layers of carbon fiber fabric) made with commercially available epoxy and a bio-based epoxy resins (31% bio content) are compared. Tensile tests on the investigated resins and tensile, compression, shear and flexural tests have been carried out on composite laminates manufactured with the two investigated resins. A finite element model has been calibrated in the LS-Dyna environment using the experimentally assessed mechanical properties. The experimental results have proven that the two composites showed similar quasi-static properties, proving that bio-based composite materials can be reliably employed as a substitute for epoxy resins without affecting the structural integrity of the component but lowering their carbon footprint.

A highly thermally stable benzoxazine resin derived from norbornene and natural renewable tyramine and furfurylamine

Highly thermally stable polymeric materials synthesized from renewable resources are highly desirable in many high-performance fields due to the sustainable development of human beings. Herein, a new norbornene-containing monobenzoxazine thermosetting resin (HPTM-fa) exhibiting very high thermal stability has been prepared using natural bio-resourced tyramine and furfurylamine as starting materials. The structural details of HPTM-fa were characterized by FT-IR, NMR as well as high-resolution mass spectroscopies. The polymerization behaviors of cross-linkable norbornene, oxazine ring, and furan groups in HPTM-fa were investigated by DSC and in situ FT-IR analyses. In addition, the polybenzoxazine thermoset derived from this newly obtained bio-based mono-benzoxazine resin showed very high thermal stability with a Td5 of 413 °C and a glass transition temperature of 290 °C. The outstanding performance of thermoset based on HPTM-fa evidences its potential applications in the design of highly thermally stable polymeric materials.

Magnetic- and light-responsive shape memory polymer nanocomposites from bio-based benzoxazine resin and iron oxide nanoparticles

Shape memory polymers (SMPs) are a class of smart materials that can be programmed to recover from temporary shape to permanent shape by applying external stimuli (temperature, magnetic field, light, electric field, and moisture, etc.). This unique property of SMPs makes them an appealing candidate in application for soft robotics, such as smart actuators, artificial muscles, and biomedical devices. In this contribution, we have developed multi-stimuli-responsive SMPs from bio-based benzoxazine resin and iron oxide nanoparticles (Fe3O4 NPs) that could be actuated by magnetic field and light. The nanocomposites were characterized by infrared spectroscopy, in which molecular interaction between benzoxazine/epoxy copolymers and Fe3O4 NPs was observed. Effects of nanoparticle content (0–5 wt%) on magnetic, mechanical, thermal, and thermo-mechanical properties of nanocomposites were investigated. Shape memory performance of nanocomposites was significantly improved with incorporation of Fe3O4 NPs. Shape fixity increased from 85% of neat copolymers to 93% of copolymers filled with 3 wt% Fe3O4 NPs, while shape recovery increased from 94% to 98%. Moreover, shape fixity could be done without external force contact by 808 nm-light actuation and magnetic attraction, due to photothermal and magnetic properties of nanocomposites. Shape recovery was tested under actuation by magnetic field. The highest shape recovery ratio was 99% within 26 s for copolymers filled with 5 wt% Fe3O4 NPs. Lastly, preliminary application of nanocomposites was demonstrated as they could push a 1 g-object within 10 s of actuation by magnetic field. In overall, these nanocomposites with multi-stimuli-responsive shape memory property had a good potential to be applied for soft robotics.

Recent Advances on the Production of Itaconic Acid via the Fermentation and Metabolic Engineering

Itaconic acid (ITA) is one of the top 12 platform chemicals. The global ITA market is expanding due to the rising demand for bio-based unsaturated polyester resin and its non-toxic qualities. Although bioconversion using microbes is the main approach in the current industrial production of ITA, ecological production of bio-based ITA faces several issues due to: low production efficiency, the difficulty to employ inexpensive raw materials, and high manufacturing costs. As metabolic engineering advances, the engineering of microorganisms offers a novel strategy for the promotion of ITA bio-production. In this review, the most recent developments in the production of ITA through fermentation and metabolic engineering are compiled from a variety of perspectives, including the identification of the ITA synthesis pathway, the metabolic engineering of natural ITA producers, the design and construction of the ITA synthesis pathway in model chassis, and the creation, as well as application, of new metabolic engineering strategies in ITA production. The challenges encountered in the bio-production of ITA in microbial cell factories are discussed, and some suggestions for future study are also proposed, which it is hoped offers insightful views to promote the cost-efficient and sustainable industrial production of ITA.

Methacrylated wood flour-reinforced “all-wood” derived resin for digital light processing (DLP) 3D printing

Additive manufacturing (AM) has led to the immense design freedom and fast production rates of wood-polymer composites (WPCs). However, vat photopolymerization-based AM techniques such as digital light processing (DLP) have yet to be exploited for the fabrication of complex and high resolution WPCs. This work demonstrates a microwave-assisted strategy for the rapid hydrophobization and functionalization of wood flour with methacrylate groups, in order to enhance its compatibility and interfacial interaction with novel wood-monomer derived photopolymer resins. The efficiency of this approach was exemplified in the inclusion of a high loading amount (10 wt%) of methacrylated wood flour to a biobased resin consisting of methacrylated eugenol and vanillin, without compromising the resin's dispersion stability and printability. Ultimately, the development of the resin culminated in the successful DLP 3D printing of wood flour-reinforced biobased composites that exhibited increases of 617%, 482%, and 31% in tensile strength, Young's modulus, and elongation at break, respectively, compared to resins without wood flour.

A solvent-free and scalable method to prepare alkali soluble soybean oil-based epoxy acrylic resin for photoresist application

The raw materials of commercial resin for photoresists nearly all come from petroleum resources. To follow the policy of “green chemistry”, it is urgent to employ renewable, biodegradable, green biomass resources instead of petroleum for the construction of photoresist resin. In this study, the alkaline soluble biobased epoxy acrylic resins are successfully prepared via a ring-opening reaction of epoxidized soybean oil (ESO) with the modified acrylic precursor (MMHEA), followed by diisocyanate modifying to introduce a small amount of polyurethane. The structures of the precursor and product resin are characterized and determined by FT-IR and 1 H NMR analysis. Subsequently, the properties of the resins and the related UV-curable coating films are tested detailedly. The results show that the product resin modified by diisocyanate possesses significantly improved viscosity (higher than 123 Pa s), and the UV-curable coating film containing hexamethylene diisocyanate has a moderate crosslinking density of 1443.18 mol m -3 and the excellent mechanical performances with the tensile strength of 20.40 ± 0.53 MPa, elongation at break of 30.74 ± 1.00% and toughness of 4.44 ± 0.11 MJ m -3 . Moreover, the UV-curable coating films can dissolve completely in 10 wt% NaOH solution at room temperature within 40 min. The prepared product resin is in line with the requirements of photoresist, which can be used in the printed circuit boards. This study develops and provides a solvent-free and one-pot method to prepare biobased epoxy acrylic resins, which are suitable to use as photoresist resin. The use of biomass raw materials and green UV-curing technology follows the principles of green chemistry. And the preparation method of biobased functionalized resins with universal applicability can be easily extended to use in large-scale industrial resin production construction. • A renewable polyfunctional resin was prepared from epoxy soybean oil. • The UV-curable resin with alkali solubility can be used for the photoresist. • Good toughness, thermal stability and crosslinking density properties of resin. • The utilization rate can reach 100% by solvent-free and one-pot method. • The resin can be used in large-scale industrial production applications.

Avient launches new density modified polymers with recycled and bio-based content, supplies composites to innovative tripod and predicts color trends.

On January 23, 2023, Avient Corporation announced the expansion of its Gravi-Tech™ Density Modified Formulations portfolio to include more sustainable grades based on recycled and bio-based resin and/or filler, reportedly without sacrificing performance. First-generation Gravi-Tech Density Modified Formulations were developed to mimic the luxurious look, weight, and feel of die-cast or machined metals by using select metallic fillers and thermoplastic resin. These are claimed to be a cost-effective alternative to metal, useful for applications in luxury packaging and consumer goods including caps and closures for cosmetics, bottle caps and boxes for spirits, and decorative knobs and grips for appliances, furniture, and automotive applications.

Eco-friendly synthesis of cardanol-based AB monomer for formaldehyde-free phenolic thermosets

Oxidative cleavage of cardanol to a single-component AB monomer allows the preparation of bio-based formaldehyde-free phenolic resins.

Microwave-assisted organosolv extraction for more native-like lignin and its application as a property-enhancing filler in a light processable biobased resin

The more native-like lignin microwave extracted from spruce wood greatly reinforced digital light processing 3D printed biobased materials already at low concentration.

Green composites from vanillin-based benzoxazine and silane surface modified chopped carbon fibers

By following the rules of green chemistry, a novel composite is developed from a renewable and ecofriendly resource, namely, vanillin. The latter was used as a phenolic precursor for the microwave synthesis of a bio-based benzoxazine resin (Va-BZ). Afterward, high-performance green composites were developed by reinforcing Va-BZ with various amounts of chopped silane surface modified carbon fibers (CFs). The chemical structure of the Va-BZ monomers was confirmed by 1H NMR and Fourier transform infrared spectroscopy. The grafting of the silane moiety on the CF surface was assessed by FTIR and TGA analyses. The autocatalytic ring opening polymerization of the Va-BZ monomers was confirmed by DSC analysis. The mechanical performances of the developed green composites were studied by flexural and tensile investigations. The findings suggested that the maximum amount of 20 wt. CFs afforded the best results, with flexural and tensile strengths of 450 and 462 MPa, respectively. The SEM was used to study the fractured tensile surfaces and elucidated the toughening mechanism. Meanwhile, the TGA showed that the introduction of the CFs markedly improved the thermal stability of the benzoxazine matrix. Overall, this study confirmed that greener approaches can also result in high-performance composites satisfying the needs of exigent applications.

Tannin-Epoxidized Soybean Oil as Bio-Based Resin for Fabrication of Grinding Wheel.

Formaldehyde-free epoxidized soybean oil-based resin has been prepared under acidic conditions by co-condensation of the epoxidized soybean oil and condensed tannin originating from agricultural and forestry sources as the main raw materials, whereas 1,6-hexanediamine was employed as a cross-linking agent. Fourier transform infrared spectroscopy (FTIR) and electrospray ionization (ESI) corroborated that tannin and epoxidized soybean oil underwent crosslinking under acidic conditions supported by hexamethylenediamine. A bio-based grinding wheel was fabricated by formulation of the developed resin with wood powder as source of grinding particles. The appearance, hardness, compressive strength and wear resistance of the resulting grinding wheel were studied. The results have shown that the grinding wheel possesses a smooth surface with no bubbles or cracks, and its hardness and wear resistance were greater than that of a phenolic resin-based grinding wheel. Interestingly, the grinding wheel incorporates more than 90% of its raw materials as biomass renewable materials; thus, it is generally considered non-toxic. In addition, the future feasibility of this approach to replace some petrochemical resins that are frequently used in the fabrication of grinding wheels is considered.

In-situ selective epoxidation of Colocynthis Vulgaris shrad seed oil for the synthesis of a methacrylated biobased resin; An artificial neural network (ANN) modelling approach

Colocynthis Vulgaris shrad seed oil (CVSSO) contains unsaturated fatty triglycerides predominantly (oleic, linoleic and linolenic acid), indicating its suitability for epoxide development. The challenges associated with petroleum-based epoxides, such as price escalation, non-renewability and environmental pollution, have led the research for its substitution with vegetable-based epoxide; artificial intelligence techniques have been adopted to model and predict complex processes. This study predicted CVSSO epoxidation parameters using an Artificial Neural Network (ANN). First, pure CVSSO was epoxidized via a conventional in-situ method with peroxyacetic acid. Then, methacrylated biobased resin was synthesized by further modifying the epoxidized oil with methacrylic acid in the presence of hydroquinone. The input parameters of the neural networks are time, temperature, composition and stirring speed, while the output parameters are iodine value, oxirane value, conversion, yield and selectivity. ANN was evaluated with 11 backpropagation (BP) algorithms; each algorithm was evaluated with four neurons in the input layer, a hidden layer with ten neurons and an output layer with five neurons. Coefficient of determination (R 2 ) and mean square error (MSE) have been implemented and correlated to test the adequacy and predictive ability of the model. Results showed that the Levenberg Marquardt algorithm gave a good prediction for iodine and oxirane value with mean square error (MSE) of 2.2397E-11 and 1.67718E-12; at the same time, Bayesian regularization predicted conversion, yield and selectivity with MSE of 4.3925E-12, 1.86759E-12 and 8.53013E-13 respectively; nevertheless, Levenberg Marquardt and Bayesian regularization gave the best prediction than other different BP algorithms. Other statistical indicators such as mean absolute error (MAE) showed 0.0232,0.0781,8.14,12.13 and 19.73), while mean absolute percentage error (MAPE) gave (0.00028%, 0.000864%, 0.000376%, 0.00019% and 0.00017%) for iodine value, oxirane value, conversion, yield and selectivity respectively; the results indicate a high forecast on the ANN simulated process parameters and suggest a good agreement between the experimental ad predicted values. The characterization results from physicochemical and FTIR analysis indicated that CVSSO was suitably epoxidized, and further modification to Methacrylated epoxidized Colocynthis Vulgaris shrad oil (MECVSSO) was actualized. These results show that ANN can potentially estimate epoxidation parameters of CVSSO. This development may have significant potential to improve the product quality of epoxides and reduce time and cost by minimizing epoxidation experiments.

Effect of diluent on the properties of intrinsically flame-retardant vinyl ester resins and their fiberglass-reinforced composites

To overcome the flammability and severe smoke release of vinyl ester resin and to explore the effect of a diluent on its properties and those of fiberglass-reinforced composites, a bio-based vinyl ester resin monomer was prepared from magnolol and glycidyl methacrylate. Its structure was confirmed by Fourier-transform infrared spectroscopy and 1H and 13C nuclear magnetic resonance spectrometry. The monomer was dissolved in styrene and methacrylic acid to obtain bio-based resins designated as SDAR and MADAR, respectively, and their fiberglass-reinforced composites GFSDAR and GFMADAR were prepared. Dynamic mechanical analysis showed that MADAR (142.8 °C) and its composite (146.2 °C) have higher glass transition temperatures than SDAR (112.1 °C) and its composite (122.3 °C). Bending tests on GFMADAR showed that its flexural strength (378.9 MPa) and flexural modulus (19.95 GPa) is higher than those of GFSDAR (247.7 MPa and 16.27 GPa, respectively) due to better wettability of fiberglass. Cone calorimeter results indicated that the total heat release and total smoke production of GFMADAR are reduced by 19.5% and 31.9% compared with those of GFSDAR. The good wettability of MADAR on fiberglass and strong contact between its char residue and fiberglass endow GFMADAR with superior flame retardancy and smoke suppression. This work demonstrates a new method for preparing high-performance vinyl ester resin and its fiberglass-reinforced composite.