Bio-based Polymeric Materials Research Articles

Optimization of reed-based polyol production driven by response surface methodology and machine learning: Process modeling and hydroxyl value prediction

In pursuit of sustainable development goals, the transformation of biomass resources into high-value chemicals has become a focal point within the academic community. Despite being a biomass resource, reed (Phragmites australis) has not yet fully realized its potential in the production of bio-based polyols. This study utilized Response Surface Methodology (RSM) and an Artificial Neural Network (ANN) enhanced by a Genetic Algorithm (GA) to model and optimize the liquefaction process of reeds. Furthermore, this study employed a pre-existing predictive model to estimate the hydroxyl value of reed-derived liquefaction products, thereby aiming to curtail expenses during the biomass chemical development phase. The results demonstrated that both the RSM and GA-ANN models accurately predict bio-polyol yield, with the RSM model outperforming the ANN model. Based on optimal conditions predicted by the RSM model, the best experimental process parameters were established: raw material particle size 2–12 mesh, solid-liquid ratio 5:1, glycerol content 32.5 %, catalyst content 3.6 %, temperature 169 °C, and reaction time 58 minutes. Under these conditions, the polyol yield reached 89.145 %, with a relative deviation of 2.366 %, and the bio-polyol exhibited a viscosity of 0.51 Pa·s. The predicted hydroxyl value for the bio-based polyol was found to be 399.19 mg KOH/g. The liquefied product is rich in hydroxyl groups, indicating its potential application value in preparing bio-based polymer materials. This study introduces innovative approaches to the economical production of bio-based polyols at the laboratory scale, which may pave the way for their broader industrial implementation.

Synthesis and characteristics properties of lignified PVA copolymer with enhanced UV-blocking performance and water solubility

The increasing environmental concerns have heightened the pursuit of sustainable materials, with a particular emphasis on biodegradable polymers. Polyvinyl alcohol (PVA), a recognized biodegradable synthetic polymer, faces challenges such as cost, slow biodegradation, and limited UV resistance. This study explores lignin, an abundant and eco-friendly biopolymer, as a cost-effective additive to enhance PVA properties via the copolymerization technique. The Mannich reaction was utilized to effectively alkylate lignin with allylthiourea, leading to the synthesis of a lignin-based macromonomer (LATU). Subsequently, the LATU macromonomer was copolymerized with vinyl acetate, producing Poly(VAc-Co-LATU) copolymer in a reaction conducted at 70 °C for 6 h. Finally, the copolymers were hydrolyzed (saponification) with potassium hydroxide to obtain Poly(VA-Co-LATU) copolymers. Extensive investigations, including FTIR, XPS, XRD, and 1H NMR, effectively validated the synthesis of the copolymers. The high monomer conversion rate above 89 % emphasizes the effectiveness of the synthesis method. The addition of LATU has a direct impact on the crystalline structure of the copolymer. X-ray diffraction patterns indicate a reduction in crystallinity, which in turn affects the other properties of the synthesized copolymers. Consequently, the lignified copolymer, Poly(VA-co-LATU), exhibited slight decrease in molecular weight (Mw), improved UV-blocking effectiveness, and greater solubility in water as comparison to PVA. This study demonstrates the feasibility of using lignin as a monomer to create novel bio-based polymeric materials that exhibit the necessary properties for certain applications.

Single-use commercial bio-based plastics under environmental degradation conditions: Is their biodegradability and compostability a fact?

Evaluating compostability is increasingly essential for proving commercial bio-based cutlery or packaging since these materials must biodegrade under controlled conditions quickly. Utensils for eating represent Mexico's most popular consumer single-use materials, and Mexican regulations based on biodegradation or compostability are still vague and lack scientific evaluations. This study analyzed three bio-based polymeric materials (bags, dishes, and forks) from commercial brands following Mexican regulations and using various analytical techniques to verify their biodegradability and compostability. First, weight loss measurements, stress-strain tests, and topographic imaging were applied for preliminary observations at the macro scale up to 90 days of compostability. Besides, spectroscopy, microscopy, and thermal techniques indicate changes and behavior of the bio-based materials depending on the composition. The results suggest that bags exhibited the highest decomposition rate (80 %) compared to dishes and forks. Similarly, mechanical resistance indicates a reduction of 62 % for bags, 30 % for dishes, and almost none for forks. Texture image analysis revealed that the complexity and roughness of the materials increased over time, correlating with the physical changes observed. These results indicate minimal surface topography changes and higher stiffness for dishes and forks, indicating low biodegradability. SEM images supported these findings, showing surface degradation in bags and dishes but not in forks. FTIR and XRD analyses confirmed the presence of polyamide (bags) and polypropylene (dishes and forks). These results reduce biodegradation and differ from the claims made by manufacturers. The thermal analysis found similar results, indicating that the materials' thermal stability decreased after degradation, which is related to lower biodegradability and compostability. Overall, the study concluded only bags meet the criteria for compostability in national regulations. However, dishes and forks made of petroleum-derived polymers have higher resistance to natural and microbial degradation.

Aromatic Biobased Polymeric Materials Using Plant Polyphenols as Sustainable Alternative Raw Materials: A Review

In the foreseeable future, the development of petroleum-based polymeric materials may be limited, owing to the gradual consumption of disposable resources and the increasing emphasis on environmental protection policies. Therefore, it is necessary to focus on introducing environmentally friendly renewable biobased materials as a substitute for petroleum-based feed stocks in the preparation of different types of industrially important polymers. Plant polyphenols, a kind of natural aromatic biomolecule, exist widely in some plant species. Benefiting from their special macromolecular structure, high reactivity, and broad abundance, plant polyphenols are potent candidates to replace the dwindling aromatic monomers derived from petroleum-based resources in synthesizing high-quality polymeric materials. In this review, the most related and innovative methods for elaborating novel polymeric materials from plant polyphenols are addressed. After a brief historical overview, the classification, structural characteristics, and reactivity of plant polyphenols are summarized in detail. In addition, some interesting and innovative works concerning the chemical modifications and polymerization techniques of plant polyphenols are also discussed. Importantly, the main chemical pathways to create plant polyphenol-based organic/organic–inorganic polymeric materials as well as their properties and possible applications are systematically described. We believe that this review could offer helpful references for designing multifunctional polyphenolic materials.

Dynamic covalently bio-based polyurethane-boron nitride nanosheet composites for effective self-healing and thermal management

Polymer-based composites, such as polyurethane-based composites, provide better corrosion and fatigue resistance than other materials, but their poor thermal conductivity limits their application areas. In this study, using boron nitride nanosheets (BNNSs), cardanol (CA), and 2-hydroxyethyl disulfide (HEDS) as raw materials, we have developed an innovative dynamically covalently crosslinked bio-based polyurethane thermal management composite filled with BNNSs, which takes into account the sustainability of the bio-based polyurethane and the excellent thermal conductivity of BNNSs. We further explored the effect of different BNNSs content ratios on the material properties, and we found that the thermal conductivity could improve by 156 % at 10 wt% BNNSs-doping. Meanwhile, the dynamic covalent cross-linking strategy endows the material with self-healing ability after physical damage. Incorporating disulfide bonds allows the samples to be dynamically reversible at certain temperatures to repair material damage and remodel for recycling. The development of this material offers a new approach to enhancing the performance of bio-based polymer materials. It provides a new avenue for designing and applying eco-friendly materials with high thermal conductivity.

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.