Bio-based Polymeric Materials Research Articles

Overcoming Challenges of Lignin Nanoparticles: Expanding Opportunities for Scalable and Multifunctional Nanomaterials.

ConspectusThe increasing demand for polymeric materials derived from petroleum resources, along with rising concerns about climate change and global plastic pollution, has driven the development of biobased polymeric materials. Lignin, which is the second most abundant biomacromolecule after cellulose, represents a promising renewable raw material source for the preparation of advanced materials. The lucrative properties of lignin include its high carbon content (>60 atom %), high thermal stability, biodegradability, antioxidant activity, absorbance of ultraviolet radiation, and slower biodegradability compared to other wood components. Moreover, the advent of lignin nanoparticles (LNPs) over the last ten years has circumvented many well-known shortcomings of technical lignins, such as heterogeneity and poor compatibility with polymers, thereby unlocking the great potential of lignin for the development of advanced functional materials.LNPs stand out owing to their well-defined spherical shape and excellent colloidal stability, which is due to the electrostatic repulsion forces of carboxylic acid and phenolic hydroxyl groups enriched on their surface. These forces prevent their aggregation in aqueous dispersions (pH 3-9) and provide a high surface area to mass ratio that has been exploited to adsorb positively charged compounds such as enzymes or polymers. Consequently, it is not surprising that LNPs have become a prominent player in applied research in areas such as biocatalysis and polymeric composites, among others. However, like all ventures of life, LNPs also face certain challenges that limit their potential end-uses. Solvent instability remains the most challenging aspect due to the tendency of these particles to dissolve or aggregate in organic solvents and basic or acidic pH, thus limiting the window for their chemical functionalization and applications. In addition, the need for organic solvent during their preparation, the poor miscibility with hydrophobic polymeric matrices, and the nascent phase regarding their use in smart materials have been identified as important challenges that need to be addressed.In this Account, we recapitulate our efforts over the past years to overcome the main limitations mentioned above. We begin with a brief introduction to the fundamentals of LNPs and a detailed discussion of their associated challenges. We then highlight our work on: (i) Preparation of lignin-based nanocomposites with improved properties through a controlled dispersion of LNPs within a hydrophobic polymeric matrix, (ii) Stabilization of LNPs via covalent (intraparticle cross-linking) and noncovalent (hydration barrier) approaches, (iii) The development of an organic-solvent-free method for the production of LNPs, and (iv) The development of LNPs toward smart materials with high lignin content. Finally, we also offer our perspectives on this rapidly growing field.

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.

Photo-curable bio-based comb/bottle brush epoxy resin/beeswax/copper foam phase change materials with high enthalpy value, high conductivity, and multifunctional properties

At present, the demand for green energy has reached a new height in history, and thermal energy storage technology has been widely used to reduce energy consumption. It is still a challenge to develop bio-based polymeric form-stable phase change materials (FSPCMs) with high enthalpy value and thermal conductivity (TC), short curing time, and multifunctional properties. This work not only exploited a series of adjustable and photo-curable comb/bottle brush bio-based epoxy resin/beeswax (bw) FSPCMs with the above superiorities, but also revealed the effects of cross-linking density on the energy storage capacity and encapsulation rate of the FSPCMs. As a result, the optimal system can encapsulate the maximum amount of bw (60 wt%) and obtain the highest enthalpy value (142.1 J/g) with only 0.5% enthalpy loss. Through further introducing the optimal curing system into the copper (Cu) foam, the electromagnetic interference shielding property, TC, tensile strength, and photo-thermal conversion efficiency of the final composite (modified by Cu of 95% porosity) can reach 110 dB, 2.387 W m−1K−1, 2.81 MPa, and 80%, respectively, and the enthalpy value (84.2 J/g) is still satisfactory. This study can provide theoretical guidance for the structural design of reliable fast photo-curable bio-based polymeric FSPCMs with excellent phase change performances and multifunctional properties.

Olive industry liquid waste from trash to metal adsorbent for wastewater purification

The development of biobased polymeric materials for wastewater purification has become a demand due to the growing need for water free of hazardous metal ions for safe purposes. The organic components of the OLLW including carbohydrates, phenolics, aromatic acids and others are cost-effective and sustainable choices for this application. This work focuses on a method for turning the organic components of liquid waste from the olive industry (OILW) into a foam-based value-added polymer that has several metal ion binding sites. The process of making the target polymers involved reacting the components of the OILW with hexamethylene diisocyante and 1,4-phnyelene diisocynate to create the polymeric materials LHMIDIC and LPDIC that are in foam forms with urethane linkages, respectively. The adsorption competence of the polymeric foams toward Pb(II) was evaluated as a function of various parameters including adsorbent dose, pH, temperature, initial ion concentration and time. The optimum parameters values that led to a quantitative removal of Pb(II) were identified. The obtained thermodynamic parameters showed that the adsorption by the two foams was spontaneous at room temperature. The isothermal and kinetic values showed that the adsorption by synthesized foams follows a second order kinetic and obeys the Langmuir isothermal model. The foams showed a high tendency for removing multi metal ions present in a real sample of wastewater. The original nature of the starting material used in making the foam, cost and the obtained results showed the potential of using the foam in a large-scale plants of wastewater purification.Graphical

Bacterial Population Changes during the Degradation Process of a Lactate (LA)-Enriched Biodegradable Polymer in River Water: LA-Cluster Preferable Bacterial Consortium.

The lactate-based polyester poly[lactate (LA)-co-3-hydroxybutyrate (3HB)], termed LAHB, is a highly transparent and flexible bio-based polymeric material. There are many unknowns regarding its degradation process in riverine environments, especially the changes in bacterial flora that might result from its degradation and the identities of any LAHB-degrading bacteria. LAHB were immersed in the river water samples (A and B), and LAHB degradation was observed in terms of the weight change of the polymer and the microscopic changes on the polymer surfaces. A metagenomic analysis of microorganisms was conducted to determine the effect of LAHB degradation on the aquatic environment. The bacterial flora obtained from beta diversity analysis differed between the two river samples. The river A water sample showed the simultaneous degradation of LA and 3HB even though the copolymer was LA-enriched, suggesting preferable hydrolysis of the LA-enriched segments. In contrast, only 3HB degraded for the LAHB in the river B water sample. The linear discriminant analysis effect size (LEfSe) analysis revealed 14 bacteria that were significantly increased in the river A water sample during LAHB degradation, suggesting that these bacteria preferentially degraded and assimilated LA-clustering polymers. Our metagenomic analysis provides useful insights into the dynamic changes in microbial communities and LA-clustering polymer-degrading bacteria.

Future perspectives of biopolymeric industry

Abstract Because of some specific properties such as hydrophilicity, poor mechanical strength, barrier properties, and other characteristics, biopolymers and biocomposite materials are not suitable for various important industrial applications. In the last few decades, the demand for biopolymers and their composites has increased continuously due to the extensive use of fossil resources or stock resources. Hence, eco-friendly biomaterials are highly essential for maintaining the sustainability of the environment. Now, biomaterials are considered highly promising materials that can be used as proper substitutes for fossil-based synthetic polymers and their composites through proper modification of the biopolymers. Recently, a novel non-biodegradable biomaterial (polythioesters) has been developed through microbial fermentation. Researchers throughout the globe are now developing improved biocomposite materials by incorporating different fillers in the nanoscale range that exhibit adequate mechanical properties and can be designed as future biomaterials that can replace traditional plastics. Now biopolymers and bionanocomposites are used noticeably in many countries throughout the world for food packaging, cosmetics, automobile industries, water purification, tissue engineering, textile industries, electronic industries, etc. For the industrialization of biobased polymeric materials and bionanocomposite materials, they should be synthesized in a sophisticated way by using green technology with improved geometry, good control in internal architecture, mechanical properties, and porosity. Chitin, alginate, pectin, zein, chitosan, poly-glutamic acid (-PGA), and other natural biopolymers are now found to be the future materials for various bioplastic industries. However, the future prospects of the biopolymer industry still pose challenges for industrialization and commercialization and should not be overlooked lightly.

Fully bio-based thermosetting polyimine vitrimers with excellent adhesion, rapid self-healing, multi-recyclability and antibacterial ability

Traditional thermosetting materials cannot be degraded, recycled, or reprocessed once they attain their end-of-life causing environmental pollution. Using renewable feedstocks to develop covalent adaptive networks (CANs) based on dynamic covalent bonds can make up for the above shortcomings. The design of new polymeric materials using renewable feedstocks is consistent with the concept of sustainability practices. Herein, castor oil, cysteamine and vanillin are used as building blocks to construct fully bio-based thermosetting polyimine vitrimers through imination between cysteamine functionalized castor oil and divanillin. Owing to its unique structure containing flexible chains, aromatic hydrocarbon and imine bonds, polyimine vitrimers integrate fine mechanical properties, good thermal stability, excellent adhesion, rapid self-healing performance, degradability, recyclability and antibacterial ability. Specifically, the tensile strength of 5.21 MPa, lap-shear strength of 6.07 MPa on 304 stainless steels, self-healing within 30 min at 80 °C, and antibacterial rate against Staphylococcus aureus and Escherichia coli > 90% are observed for this fully bio-based polyimine vitrimers. Additionally, discarded materials can be recovered multiple times for repeated usage by thermo-compression reprocessing and solvent treatment. The original monomer DV is obtained by degradation under 1 M aqueous acetic acid solution with a recovery rate of 92.7%. Therefore, this work will provide a new research strategy for the application of multifunctional bio-based polymer materials, especially in adhesives.

Preparation and Characterization of Bio-Based PLA/PEG/g-C3N4 Low-Temperature Composite Phase Change Energy Storage Materials.

As energy and environmental issues become more prominent, people must find sustainable, green development paths. Bio-based polymeric phase change energy storage materials provide solutions to cope with these problems. Therefore, in this paper, a fully degradable polyethylene glycol (PEG20000)/polylactic acid (PLA)/g-C3N4 composite phase change energy storage material (CPCM) was obtained by confinement. The CPCM was characterized by FTIR and SEM for compatibility, XRD and nanoindentation for mechanical properties and DSC, LFA, and TG for thermal properties. The results showed that the CPCM was physical co-mingling; when PLA: PEG: g-C3N4 was 6:3:1, the consistency was good. PEG destroys the crystallization of PLA and causes the hardness to decrease. When PLA: PEG: g-C3N4 was 6: 3: 1, it had a maximum hardness of 0.137 GPa. The CPCM had a high latent enthalpy, and endothermic and exothermic enthalpies of 106.1 kJ/kg and 80.05 kJ/kg for the PLA: PEG: g-C3N4 of 3: 6: 1. The CPCM showed an increased thermal conductivity compared to PLA, reaching 0.30 W/(m·K),0.32 W/(m·K) when PLA: PEG: g-C3N4 was 6: 3: 1 and when PLA: PEG: g-C3N4 was 3: 6: 1, respectively. Additionally, the CPCM was stable within 250 °C, indicating a wide appliable temperature range. The CPCM can be applied to solar thermal power generation, transportation, and building construction.

Bio-Based Polymeric Flocculants and Adsorbents for Wastewater Treatment

With the growing demand for clean and safe water, there is a pressing need to explore novel materials for water treatment applications. In this regard, bio-based polymeric materials have emerged as a promising solution for water purification. This article highlights the numerous advantages offered by bio-based polymeric materials, including their biodegradability, low cost, and renewable nature. Moreover, it discusses in depth the two primary applications of these materials in water treatment, namely flocculation and adsorption, showcasing their effectiveness in removing contaminants. Furthermore, this review addresses the future prospects and challenges associated with the development of bio-based polymeric materials for water treatment applications. This review provides valuable insights for researchers in the field, driving further advancements in the utilization of bio-based polymeric materials to ensure clean and sustainable water resources.

Thermal-oxidation degradation of polylactic acid/cellulose nanocrystal composites: Effects of surface chemistry

Cellulose nanocrystal (CNC) is one of the most attractive renewable nano-fillers for polylactic acid (PLA). Depending on the production routes and starting cellulose sources, CNC possesses different surface chemistry, surface charge density, and morphology. However, the effect of the CNC surface chemistry on the thermal-oxidation degradation behaviors of PLA/CNC composites is still elusive, although it is a crucial factor in determining the hot processing and service of composites. In this work, sulfated (CNC-S), carboxylated (CNC-O), and uncharged CNC (CNC-Cl) were produced and compounded with PLA via a two-step masterbatch method, respectively. The thermal-oxidation degradation behaviors of the obtained composites were systematically investigated to elucidate their degradation mechanisms. Results show that the surface uncharged CNC produced by hydrochloric acid hydrolysis contributes to the thermal-oxidation stability of composites, but is more prone to agglomerate due to the lack of electrostatic repulsion. Compared with uncharged CNC, negatively charged CNCs (CNC-S and CNC-O) appear better dispersion state in the PLA matrix. However, PLA/CNC-S composites present relatively lower weight loss temperature and degradation activation energy due to the acceleration of desulfation process on thermal-oxidation degradation. Contrary to expectations, the addition of carboxylated CNC has almost no negative effect on the thermal oxygen stability of PLA because the decarboxylation reaction during melt-processing converts carboxyl groups to volatile by-products. This study sheds light on the thermal-oxidation degradation mechanism of PLA/CNC composites and will be a valuable reference for further research into the degradation of other bio-based polymeric materials.

Characteristics of 3D Printed Biopolymers for Applications in High-Voltage Electrical Insulation.

Three-dimensional printing technology is constantly developing and has a wide range of applications; one application is electrical insulation, where the standard technology uses polymer-based filaments. Thermosetting materials (epoxy resins, liquid silicone rubbers) are broadly used as electrical insulation in high-voltage products. In power transformers, however, the main solid insulation is based on cellulosic materials (pressboard, crepe paper, wood laminates). There are a vast variety of transformer insulation components that are produced using the wet pulp molding process. This is a labor-intensive, multi-stage process that requires long drying times. In this paper, a new material, microcellulose-doped polymer, and manufacturing concept for transformer insulation components are described. Our research focuses on bio-based polymeric materials with 3D printability functionalities. A number of material formulations were tested and benchmark products were printed. Extensive electrical measurements were performed to compare transformer components manufactured using the traditional process and 3D printed samples. The results are promising but indicate that further research is still required to improve printing quality.

Current Applications of Bionanocomposites in Food Processing and Packaging.

Nanotechnology advances are rapidly spreading through the food science field; however, their major application has been focused on the development of novel packaging materials reinforced with nanoparticles. Bionanocomposites are formed with a bio-based polymeric material incorporated with components at a nanoscale size. These bionanocomposites can also be applied to preparing an encapsulation system aimed at the controlled release of active compounds, which is more related to the development of novel ingredients in the food science and technology field. The fast development of this knowledge is driven by consumer demand for more natural and environmentally friendly products, which explains the preference for biodegradable materials and additives obtained from natural sources. In this review, the latest developments of bionanocomposites for food processing (encapsulation technology) and food packaging applications are gathered.

Characterization of the Thermoset Blend of a Vinyl Ester Resin with Eco-friendly Epoxidized Corn Oil as a Potential Sustainable Composite Matrix Resin

In this work, we investigated the influence of a novel green flame-retardant thermoset complex matrix resin, VEECO, produced by thermoset blending of epoxidized corn oil (ECO) with a vinyl ester (VE) resin. The new polymer blend was made with the ECO content at an optimal amount of 15%. After characterization, it was discovered that the VEECO15 blend cured at 8 h had its glass transition improved by 6.38%. Regarding its mechanical properties, the improvements were as follows: flexural strength, 19.36%; modulus, 123.53%; and impact energy, 29.08%. The flammability property for the heat release rate was improved by 20.62% and, most importantly, emissions of CO and CO2 were reduced by 62.73 and 49.34%, respectively, demonstrating its potential for sustainability. As a result of the proposed synthesis mechanism, the hydrogen bonding suggests the introduction of ECO as a biobased polymeric material. Overall, the polymer blend offers a new source of hybrid eco-thermoset resin that could mitigate the increasing consumption and environmental impact of BPA-based thermoset polymers. This material is expected to be a potential source of sustainable composites for a rapidly growing carbon-free society and eco-friendly urban development.

Plant oil-derived vitrimers-graphene composites with self-healing ability triggered by multiple stimuli

Bio-based polymer materials with multi-stimuli responsiveness and multichannel self-healing ability have received significant attention due to their increasing impact on intelligent device. In this study, we report a direct construction of bio-based epoxy vitrimer (EV) from green, renewable precursors including soybean oil and tung oil that could offer new opportunities for constructions of novel polymer network intrinsically containing favorable features such as multi-stimuli response and multichannel self-healing ability, repeatable processing and recycling. Epoxidized soybean oil (ESO) and tung maleic anhydride (TMA) was used to produce a full plant oil-based EV. Tensile strengths of EVs significantly increased from 1.27 MPa to 3.7 MPa, which was due to the formation of multiple H-bonds and increased crosslink density. EVs with micropores or cracks cut achieved self-healing after heating at 200 °C in oven after 60 min. A practicable strategy for fabricating full plant oil based EV composites using graphene was developed to produce multifunctional vitrimers with self-healing ability triggered by multiple stimuli. The electricity, heat, electromagnetic wave and IR light triggered self-healing of EV composite with graphene were achieved.

Vegetable oils based precursors: modifications and scope for futuristic bio-based polymeric materials

Vegetable oils based precursors: modifications and scope for futuristic bio-based polymeric materials

Strategies for Exploiting Milk Protein Properties in Making Films and Coatings for Food Packaging: A Review.

Biopolymers of different natures (carbohydrates, proteins, etc.) recovered from by-products of industrial processes are increasingly being studied to obtain biomaterials as alternatives to conventional plastics, thus contributing to the implementation of a circular economy. The food industry generates huge amounts of by-products and waste, including unsold food products that reach the end of their shelf life and are no longer usable in the food chain. Milk proteins can be easily separated from dairy waste and adapted into effective bio-based polymeric materials. Firstly, this review describes the relevant properties of milk proteins and the approaches to modifying them for subsequent use. Then, we provide an overview of recent studies on the development of films and coatings based on milk proteins and, where available, their applications in food packaging. Comparisons among published studies were made based on the formulation as well as production conditions and technologies. The role of different additives and modifiers tested for the performances of films and coatings, such as water vapor permeability, tensile strength, and elongation at break, were reviewed. This review also outlines the limitations of milk-protein-based materials, such as moisture sensitivity and brittleness. Overall, milk proteins hold great potential as a sustainable alternative to petroleum-based polymers. However, their use in food packaging materials at an industrial level remains problematic.

Photo- and Water-Degradation Phenomena of ZnO Bio-Blend Based on Poly(lactic acid) and Polyamide 11.

The goal of this work was to investigate the morphological and chemical-physical changes induced by adding ZnO nanoparticles to bio-based polymeric materials based on polylactic acid (PLA) and polyamide 11 (PA11). Precisely, the photo- and water-degradation phenomena of nanocomposite materials were monitored. For this purpose, the formulation and characterization of novel bio-nanocomposite blends based on PLA and PA11 at a ratio of 70/30 wt.% filled with zinc oxide (ZnO) nanostructures at different percentages were performed. The effect of ZnO nanoparticles (≤2 wt.%) within the blends was thoroughly explored by employing thermogravimetry (TGA), size exclusion chromatography (SEC), matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and scanning and transmission electron microscopy (SEM and TEM). Adding up to 1% wt. of ZnO resulted in a higher thermal stability of the PA11/PLA blends, with a decrement lower than 8% in terms of molar masses (MMs) values being obtained during blend processing at 200 °C. ZnO promoted trans-ester-amide reactions between the two polymers, leading to the formation of PLA/PA11 copolymers. These species could work as compatibilisers at the polymer interface, improving thermal and mechanical properties. However, the addition of higher quantities of ZnO affected such properties, influencing the photo-oxidative behaviour and thus thwarting the material's application for packaging use. The PLA and blend formulations were subjected to natural aging in seawater for two weeks under natural light exposure. The 0.5% wt. ZnO sample induced polymer degradation with a decrease of 34% in the MMs compared to the neat samples.

Preparation and research of PCL/cellulose composites: Cellulose derived from agricultural wastes

For the rational use of agricultural wastes, bagasse, orange peel and wheat bran were used to fabricate bio-based polymer materials. Cellulose was extracted from the three different agricultural wastes, and poly(ε-caprolactone) (PCL) was used as the matrix material. PCL was mixed with nanocrystalline cellulose (CNC), extracted bagasse cellulose (GC), orange peel cellulose (JC) and wheat bran cellulose (MC) by solution casting. Morphology and structure of the extracted cellulose were studied by Scanning Electron Microscope, Fourier Infrared spectrometer, thermogravimetry and X-ray diffractometer. The influence of GC, JC, MC on the crystallization process and mechanical properties of PCL was investigated by DSC and tensile test. Experimental results show that the addition of CNC, GC, JC, MC increases the crystallization temperature of PCL, accelerates the crystallization process of PCL, and improves the tensile property of PCL.

Poly(lactic acid) based Pearl Layer Moistureproof Membrane for Flexible Laminated Packaging.

The development of bio-based polymer materials, such as polylactic acid (PLA) -based polymers, is an effective strategy to reduce dependence on petrochemical-based polymers. However, the preparation of bio-based polymers with high barrier properties is a major challenge. To overcome this challenge, a nacreous layer structure with a ' brick and mud ' pattern is mimicked to improve the overall performance of the material. In this paper, Poly (L -lactic acid) (PLLA) and Polypropylene Glycol (PPG) was combined to prepare bio-based polyurethane (PU-PLLA), which is used as the slurry structure of nacreous layer. The bio-based biomimetic composite membrane (PU-PLLA/BN) is then obtained by adding boron nitride (BN, brick structure of pearl layer) to it. The water vapor permeability test results show that the permeability of PU-PLLA material can be reduced by more than 50% by 5 wt.% BN, which is because the addition of BN can increase the length and tortuosity of the gas molecular diffusion path in the composite. Therefore, this pearl-inspired PU-PLLA/BN film has excellent moisture resistance, which opens up a broad road for the practical application of PLLA in flexible laminated packaging.

Recent Advances in Lignocellulose-Based Monomers and Their Polymerization.

Replacing fossil-based polymers with renewable bio-based polymers is one of the most promising ways to solve the environmental issues and climate change we human beings are facing. The production of new lignocellulose-based polymers involves five steps, including (1) fractionation of lignocellulose into cellulose, hemicellulose, and lignin; (2) depolymerization of the fractionated cellulose, hemicellulose, and lignin into carbohydrates and aromatic compounds; (3) catalytic or thermal conversion of the depolymerized carbohydrates and aromatic compounds to platform chemicals; (4) further conversion of the platform chemicals to the desired bio-based monomers; (5) polymerization of the above monomers to bio-based polymers by suitable polymerization methods. This review article will focus on the progress of bio-based monomers derived from lignocellulose, in particular the preparation of bio-based monomers from 5-hydroxymethylfurfural (5-HMF) and vanillin, and their polymerization methods. The latest research progress and application scenarios of related bio-based polymeric materials will be also discussed, as well as future trends in bio-based polymers.