Bio-based Composites Research Articles

Regenerated cellulose fabric reinforced bio-based polypropylene sandwich composites: fabrication, mechanical performance and analytical modelling

Sandwich composites were fabricated successfully with the balsa wood as core material and regenerated cellulose fabric bio-based polypropylene (PP) composite skins. The regenerated cellulose fabric PP composites were produced using two different methods: the conventional stacking lay-up and directly using PP pellets. Sandwich composites were made using the hot press equipment with the customized mold. The sandwich composite system and bio-composite laminate were designed to achieve very close weight to compare the key mechanical properties that each design can bear. It was evidenced from the experimental results that 416% increase in the bending load bearing property of the part can be obtained when sandwich structure was used. These experimental results were in close agreement with one of the analytical modelling utilised. The drop weight impact test results demonstrated that the sandwich specimen is capable of withstanding more than 6 kN load and absorbing the impact energy of 28.37 J.

Bio-based composites of sago starch and natural rubber reinforced with nanoclays

Bio-based composites of sago starch and natural rubber reinforced with nanoclays

Fully Bio-Based Composites of Poly (Lactic Acid) Reinforced with Cellulose-Graft-Poly-(ε-Caprolactone) Copolymers

Due to the increasing demand for modified polylactide (PLA) meeting “double green” criteria, the research on sustainable plasticizers for PLA has attracted broad attentions. This study reported an open-ring polymerization method to fabricate cellulose (MCC)-g-PCL (poly (ε-caprolactone)) copolymers with a fully sustainable and biodegradable component. MCC-g-PCL copolymers were synthesized, characterized, and used as green plasticizers for the PLA toughening. The results indicated that the MCC-g-PCL derivatives play an important role in the compatibility, crystallization, and toughening of the PLA/MCC-g-PCL composites. The mechanical properties of the fully bio-based PLA/MCC-g-PCL composites were optimized by adding 15 wt% MCC-g-PCL, that is, the elongation at break was 22.6% (~376% higher than that of neat PLA), the tensile strength was 47.3 MPa (comparable to that of neat PLA), and the impact strength was 26 J/m (~130% higher than that of neat PLA). DSC results indicated that MCC-g-PCL reduced the Tg of the PLA blend. When the addition amount was 15 wt%, the Tg of the blend was 58.4°C. Compared with MCC, MCC-g-PCL polyester plasticizer has better thermal stability, T5% (°C) can still be maintained above 300°C. The rheological results showed that MCC-g-PCL acted as a plasticizer, the introduction of PCL flexible chain increased the mobility of PLA molecular chain, and decreased the complex viscosity, storage modulus and loss modulus of PLA blends. The MCC-g-PCL derivatives, as a new green plastic additive, have shown an interesting prospect to prepare fully bio-based composites.

Graphene-based nano-functional materials for surface modification of wheat straw to enhance the performance of bio-based polylactic acid composites

To enhance wheat straw compatibility with the polylactic acid (PLA) matrix, several graphene-based materials (GBMs) derivatives, including graphene nanoplatelets, graphene oxide, and nano graphite particles with a constant fraction of 0.1 wt.-%, were employed for the surface functionalisation of wheat straw. Wheat straw surface quality was assessed by comparing PLA bio-based composites' mechanical and thermal performance with and without GBM surface functionalisation. All the resulting composites with surface functionalised straw particles exhibited higher thermal stability, flexural strength, tensile strength, and tensile toughness than those with pristine straw. This could be associated with the improved straw/PLA matrix interfacial bonding induced by the existence of GBMs on the surface of straw particles which was confirmed through morphology assessments. The mechanical properties investigations revealed maximum enhancements of 27%, 66%, and 322% for flexural strength, tensile strength, and tensile toughness, respectively, for bio-based composites consisting of graphene oxide-functionalised straw particles compared to control samples.

An automated software development for analysis of the morphological-tensile property relationship in egg shell bio-based particulate composites using machine learning algorithms

This work explored the importance of quantitative observation through imaging methods of optical and electron microscopies on the mechanical properties of particulate polymeric composites. Egg shell powder (ESP) reinforced polypropylene carbonate (PPC) polymeric composites with different filler weight percentage (wt.%) from 1 to 5 wt.% were considered. A cost-effective Image Analysis Software (IAS) was developed to extract black particles from the original optical images. During this process, the optimal image can be reproduced based on its originality by controlling the threshold values from 0.1 to 0.6 in real time situation. Using one-dimensional (1D) Gaussian distribution analysis, the authentication of the particle distribution data was studied and linked to the tensile strength of the composites. The mean value of the particle area collected from the left and right side of the scattered curves has a significant effect on the tensile strength of the composites. The proposed model was validated by comparing the predicted statistical results with the measured tensile strength for different wt.% of ESP composites. From the results obtained, a close agreement of 99% accuracy was observed between the experimental results and the proposed model for the tensile strength of the composites. The innovative study provides more practical and quantitative knowledge on improved particulate polymeric composites, in addition to the detection of failure processes through optical/electron microscopic examination of images. Evidently, the proposed cost effective, accurate and less stressful model can be employed by several composite-based industries to correlate the tensile strengths of particulate polymeric composites with their morphological properties.

Multi-objective optimization of mechanical properties of chemically treated bio-based composites using response surface methodology

Eco-friendly surface treatment of natural fibers using sodium acetate (CH3COONa) affects the mechanical properties of the developed composites in many ways. In present study, geometrically different kenaf fiber mats (bidirectional (BC), unidirectional (UD) and randomly oriented (RO) were treated at different concentration (10, 15 and 20 percentage w/w) of sodium acetate aqueous solution for varying time (24, 48 and 72 hr.) at room temperature. PLA (Poly-Lactic Acid) was used for the fabrication of treated fiber reinforced bio-degradable composites. The influence of above parameters on mechanical properties were studied. Response surface methodology (RSM) module face centered central composite design was employed for the development of regression models. The relationship between chemical treatment parameters and mechanical responses were predicted by quadratic model. In this study, predicted model was developed for two numerical factors (chemical concentration (CC) and treatment time (TT)) and one categorical factor (type of mat (TOM)). Tensile strength (TS), flexural strength (FS) and impact strength (IS) are considered as response variables. The statistical analysis showed that chemical concentration, treatment time and kenaf mat type have individually and interactively influenced the response of experiments. Chemical concentration was found to be the most influencing factor among all for the changes in mechanical properties. Optimization of input variables was done based on predicted model within bounded reason of responses.

Evaluation of the Strength of the Interface for Abaca Fiber Reinforced Hdpe and Biope Composite Materials, and Its Influence over Tensile Properties.

In this study, tensile properties of abaca-reinforced HDPE and BioPE composites have been researched. The strength of the interface between the matrix and the reinforcement of a composite material noticeably impacts its mechanical properties. Thus, the strength of the interface between the reinforcements and the matrices has been studied using micromechanics models. Natural fibers are hydrophilic and the matrices are hydrophobic, resulting in weak interfaces. In the study, a coupling agent based on polyethylene functionalised with maleic acid was used, to increase the strength of the interface. The results show that 8 wt% coupling agent contents noticeably increased the tensile strength of the composites and the interface. Tensile properties obtained for HDPE and BioPE-based coupled composites were statistically similar or better for BioPE-based materials. The use of bio-based matrices increases the possibility of decreasing the environmental impact of the materials, obtaining fully bio-based composites. The article shows the ability of fully bio-based composites to replace others using oil-based matrices.

Epoxy-poly lactic acid blended composites reinforced with carbon fibres for engineering applications

When it comes to sustainability, bio-derived materials are one of the most promising sources of polymers. They are easily accessible, affordable, and may result in a decrease in carbon emissions. The use of bio-based polymer composites lowers the dependence on petroleum-based polymers, leading to environmental degradation issues. Because of this epoxy-based composites are synthesized by combining the same with a biopolymer of Poly Lactic Acid (PLA) in varied proportions from 20 to 50 wt.% of the holding matrix. Exhaustive tests are conducted to optimize PLA percentage in the epoxy matrix. Accordingly, composites are prepared with 80% epoxy resin and 20% PLA in terms of enhanced mechanical properties. Further, these composites are strengthened by reinforcing them with CFs in varied proportions. This research emphasizes the synthesis of composite with a matrix of 80% epoxy resin and 20% PLA reinforced with CFs at 0.2 and 0.3 wt.% of the holding matrix to test their potential as a feasible composite material for engineering applications. To understand the bonding nature, thermal, and microstructural behavior of the composite material, characteristic studies such as Fourier Transform Infrared (FTIR) Spectroscopy, Thermo gravimetric analysis (TGA), and Scanning Electron microscope (SEM) images are used. Experimental results on the mechanical properties of the composites showed an increase in flexural strength by 7.62% and 3.56% for 0.2 and 0.3 wt.% of CFs reinforcements in the polymer matrix compared to pristine coupons. Simulation studies are done with ANSYS Workbench to validate the same with experimental readings and are found to be in close agreement with an error of 10–15%.

Sustainable Composites Based on Natural Rubber and Biomass Resources

Abstract: For the past two decades, environmentally friendly natural rubber composites and nanocomposites reinforced with renewable and biodegradable natural fillers has attracted increasing attention of polymer researchers from both industrial and environmental viewpoints. The use of bio-based fillers in rubber materials has emerged as extremely promising in the progress of green rubber technology. The dispersion of bio-based fillers within the rubber matrix is the key parameter that decides the overall performances of bio-based rubber composites. An important criterion for obtaining superior properties in rubber composites is good interfacial adhesion between natural fillers and natural rubber matrix, along with good dispersion and distribution of fillers within the matrix. Natural fillers represent materials that are environmentally friendly, easily available, comprising of valuable lignocellulosic fractions and are from a bio-based feedstock. Recent developments in this area focus on renewable fillers such as cellulose, chitin and lignin in its micro and nanoforms. Additionally, recent studies have focused on the use of different type of biomass residue wastes in rubber composites with a view to adapt to the recent circular economy principles. This review presents an overview of various studies and highlights in the area of bio-based filler reinforced natural rubber composites and also discusses the applications of such materials in industrial sectors.

Recent Progress on Natural Fibers Mixed with CFRP and GFRP: Properties, Characteristics, and Failure Behaviour.

Research on natural-fiber-reinforced polymer composite is continuously developing. Natural fibers from flora have received considerable attention from researchers because their use in biobased composites is safe and sustainable for the environment. Natural fibers that mixed with Carbon Fiber and or Glass Fiber are low-cost, lightweight, and biodegradable and have lower environmental influences than metal-based materials. This study highlights and comprehensively reviews the natural fibers utilized as reinforcements in polyester composites, including jute, bamboo, sisal, kenaf, flax, and banana. The properties of composite materials consisting of natural and synthetic fibers, such as tensile strength, flexural strength, fatigue, and hardness, are investigated in this study. This paper aims to summarize, classify, and collect studies related to the latest composite hybrid science consisting of natural and synthetic fibers and their applications. Furthermore, this paper includes but is not limited to preparation, mechanism, characterization, and evaluation of hybrid composite laminates in different methods and modes. In general, natural fiber composites produce a larger volume of composite, but their strength is weaker than GFRP/CFRP even with the same number of layers. The use of synthetic fibers combined with natural fibers can provide better strength of hybrid composite.

Biomimetic ultra-strong, ultra-tough, degradable cellulose-based composites for multi-stimuli responsive shape memory

Fabrication of ultra-strong, ultra-tough, sustainable, and degradable bio-based composites is urgently needed but remains challenging. Here, a biomimetic sustainable, degradable, and multi-stimuli responsive cellulose/PCL/Fe3O4 composite with ultra-strong mechanical strength and ultra-high toughness was developed. To prepare the proposed composites, the soft poly(ε-caprolactone) (PCL) side chain was grafted onto the rigid cellulose backbone, then the cellulose graft copolymer (EC-g-PCL) reacted with rigid hexamethylenediamine modified Fe3O4 nanoparticle (Fe3O4-NH2) to construct the crosslinking network using MDI-50 as a crosslinker. Given by the construction of crosslinking network and the “hard” and “soft” interactive structure, the composites showed ultra-strong mechanical strength (25.7 MPa) and ultra-high toughness (107.0 MJ/m3), and the composite specimen could lift a weight of approximately 21,200 times its mass. The composites also exhibited rapid degradation ability with high degradation efficiency. In addition, the composites showed excellent thermal responsive shape memory property with a shape recovery ratio above 96 %. Most importantly, the Fe3O4 nanoparticles endowed the composites with photothermal conversion property, the composites exhibited superior NIR light-triggered shape memory capability. The EC-g-PCL/Fe3O4 composites with ultra-strong mechanical strength and ultra-high toughness have promising applications in heavy-lift, object transportation, and self-tightening knots.

Lanthanum-modified polydopamine loaded Acinetobacter lwoffii DNS32 for phosphate and atrazine removal: Insights into co-adsorption and biodegradation mechanisms

A novel biobased composite was developed for the removal of phosphate (P) and atrazine from agricultural wastewater. A composite with strong P affinity and good biocompatibility, synthesized from La3+ and polydopamine (PDA), was immobilized onto an atrazine-degrading bacterium Acinetobacter lwoffii DNS32 (La/PDA/DNS32). Following Box-Behnken design optimization, the maximum removal rate of P (500 mg L-1) and atrazine (100 mg L-1) by La/PDA/DNS32 reached 28 % and 100 %, respectively. Density functional theory calculations revealed that La/PDA had more negative adsorption energy (−5.90 eV) than PDA alone and exhibited prominent electrophilic sites. Additionally, La/PDA-induced sorption of atrazine improved transmembrane transport and enhanced expression of degradation-associated genes in strain DNS32. La/PDA nanoparticles surrounding strain DNS32 provided a shielding effect and exhibited desirable biostability, thermal stability, and acid-alkaline resistance under contamination stress. This study demonstrates the promising potential of La/PDA/DNS32 in reducing the P and atrazine pollution caused by agricultural production.

Development of a strong soy protein-based adhesive with excellent antibacterial and antimildew properties via biomineralized silver nanoparticles

Developing eco-friendly soy protein-based adhesives instead of the extensively used aldehyde-based adhesives to fabricate wood-based panels can reduce environmental hazards and benefit human health. However, traditional soy protein-based adhesives lack long-term antibacterial and antimildew properties, reducing their bond strength and durability. Here, 3,4-dihydroxybenzaldehyde-grafted chitosan was prepared as a catechol structure donor and then introduced into the soy protein isolate (SPI) adhesive for the in situ reduction of silver ions to stable silver nanoparticles (Ag NPs); a biomineralization system was thus established. Notably, the catechol–quinone reversible redox reaction in the system endowed the resultant adhesive with excellent antibacterial (more than 99.99% bactericidal rate against Staphylococcus aureus and Escherichia coli , 91.67% bactericidal rate against Candida albicans ) and long-term antimildew properties (40 d). The wet shear strength (1.24 MPa) and prepressing bond strength (0.80 MPa) of the plywood prepared with the adhesive were increased by 63.27% and 129.63%, respectively, relative to the SPI adhesive. The volatile organic compounds release of the adhesive was 1–2 orders of magnitude lower than that of commonly used commercial adhesives. This strategy provides inspiration for reinforcing antibacterial or antimildew bio-based adhesives, hydrogels, and composites. • A system of biomineralized Ag NPs was built in the soy protein-based adhesive. • CS and SPI are used as stabilizers to avoid aggregation and agglomeration of Ag NPs. • The wet shear strength of plywood bonded by the adhesive was improved by 129.63%. • The adhesive has long-term antibacterial, mildew resistance, and low VOCs release.

Consumer response to bio-based products – A systematic review

Bio-based products represent a promising alternative to fossil-based products and contribute to reduce negative environmental consequences caused by the latter. As consumer behavior is crucial for market penetration of bio-based products, this review analyses the current state of the art in consumer research on bio-based products and aims to identify research gaps and future research needs. This review is based on a systematic synthesis of 59 scientific journal articles and one book chapter on consumer studies related to bio-based products. Peer-reviewed studies in English language, with a research focus on consumer issues related to bio-based products of plant origin, that aim to replace fossil resources, have been included in the review. Most reviewed studies investigated bio-based plastics and composites, used a quantitative research approach, have been based on established consumer theories and used non-probability sampling techniques. While consumer preferences and attitudes, conviction as well as knowledge and perception related to bio-based products were focus of many reviewed studies, consumer awareness, liking and purchasing of bio-based products have been studied rarely or not at all. The results show that many consumers are not aware of the existence of bio-based products, related knowledge is low, and labels and brands are often unknown. Additionally, some consumers have wrong assumptions about the environmental impact of bio-based materials. Consumer preferences vary between product groups, but often factors like price or functionality are more important than bio-based materials. High purchase intentions and an increased willingness to pay are found e.g. for bio-based packaging products, disposable products and plant containers (in particular for female and environmentally-concerned consumers). The review identifies important research gaps and conclusions for future research needs such as e.g., to realize more studies in countries of the global south, analyze actual purchase behavior and the regional supply situation related to bio-based products.

Cellulose Nanofibers/Pectin/Pomegranate Extract Nanocomposite as Antibacterial and Antioxidant Films and Coating for Paper.

Bio-based polymer composites find increasing research and industrial interest in different areas of our life. In this study, cellulose nanofibers (CNFs) isolated from sugar beet pulp and nanoemulsion prepared from sugar beet pectin and pomegranate extract (PGE) were used for making films and used as coating with antioxidant and antimicrobial activities for paper. For Pectin/PGE nanoemulsion preparation, different ratios of PGE were mixed with pectin using ultrasonic treatment; the antibacterial properties were evaluated to choose the formula with the adequate antibacterial activity. The antioxidant activity of the nanoemulsion with the highest antimicrobial activity was also evaluated. The nanoemulsion with the optimum antibacterial activity was mixed with different ratios of CNFs. Mechanical, greaseproof, antioxidant activity, and antibacterial properties of the CNFs/Pectin/PGE films were evaluated. Finally, the CNFs/Pectin/PGE formulation with the highest antibacterial activity was tested as a coating material for paper. Mechanical, greaseproof, and air porosity properties, as well as water vapor permeability and migration of the coated layer from paper sheets in different media were evaluated. The results showed promising applicability of the CNFs/Pectin/PGE as films and coating material with antibacterial and antioxidant activities, as well as good stability for packaging aqueous, fatty, and acidic food products.

Selected Properties of Bio-Based Layered Hybrid Composites with Biopolymer Blends for Structural Applications.

In this study, layered composites were produced with different biopolymer adhesive layers, including biopolymer polylactic acid (PLA), polycaprolactone (PCL), and biopolymer blends of PLA + polyhydroxybutyrate (PHB) (75:25 w/w ratio) with the addition of 25, 50% microcrystalline cellulose (MCC) and 3% triethyl Citrate (TEC) for these blends, which acted as binders and co-created the five layers in the elaborated composites. Modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), density profile, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) analysis were obtained. The results showed that among the composites in which two pure biopolymers were used, PLA obtained the best results, while among the produced blends, PLA + PHB, PLA + PHB + 25MCC, and PLA + PHB + 25MCC + 3TEC performed best. The mechanical properties of the composites decreased with increases in the MCC content in blends. Therefore, adding 3% TEC improved the properties of composites made of PLA + PHB + MCC blends.

Assessment of the Natural Fiber Reinforced Bio-Polyethylene Composites Flexural Macro and Micromechanical Properties

ABSTRACT One of the most common load modes is flexure. The paper measures and models the flexural strength and modulus of a bio-polyethylene reinforced with thermos-mechanical fibers from corn stover. Moreover, the authors use modified rules of mixtures to evaluate the contribution of the reinforcements to the properties of the composite. It was found a high impact of coupling agent content on the strength of the composites, and materials with a 6% of such agent and 50% of reinforcement increased 181% the strength of the matrix, and 464% its modulus. The obtained values are noticeable higher than polypropylene and some of its composites. Micromechanics analysis shows that the effect of natural fiber reinforcement on the flexural properties of a bio-based PE is similar to the effects on a polyolefin. Thus, the use of fully bio-based composites can be proposed as a substitute for some oil-based polymers, partially bio-based materials, and their composites.

Evaluation of recycled textile wastes with E-glass fabric in bio-based epoxy matrix composites: investigation of the mechanical properties

Evaluation of recycled textile wastes with E-glass fabric in bio-based epoxy matrix composites: investigation of the mechanical properties

Biobased and Programmable Electroadhesive Metasurfaces.

Electroadhesion has shown the potential to deliver versatile handling devices because of its simplicity of actuation and rapid response. Current electroadhesion systems have, however, significant difficulties in adapting to external objects with complex shapes. Here, a novel concept of metasurface is proposed by combining the use of natural fibers (flax) and shape memory epoxy polymers in a hygromorphic and thermally actuated composite (HyTemC). The biobased material composite can be used to manipulate adhesive surfaces with high precision and controlled environmental actuation. The HyTemC concept is preprogrammed to store controllable moisture and autonomous desorption when exposed to the operational environment, and can reach predesigned bending curvatures up to 31.9 m–1 for concave and 29.6 m–1 for convex shapes. The actuated adhesive surface shapes are generated via the architected metasurface structure, incorporating an electroadhesive component integrated with the programmable biobased materials. This biobased metasurface stimulated by the external environment provides a large taxonomy of shapes—from flat, circular, single/double concave, and wavy, to piecewise, polynomial, trigonometric, and airfoil configurations. The objects handled by the biobased metasurface can be fragile because of the high conformal matching between contacting surfaces and the absence of compressive adhesion. These natural fiber-based and environmentally friendly electroadhesive metasurfaces can significantly improve the design of programmable object handling technologies, and also provide a sustainable route to lower the carbon and emission footprint of smart structures and robotics.

Styrene-Free Bio-Based Thermosetting Resins with Tunable Properties Starting from Vegetable Oils and Terpenes.

The substitution of fossil-based monomers in the thermosetting formulations is a fundamental issue to face the environmental concerns related to the use of traditional resins. In this paper, styrene-free thermosetting resins were prepared to start from vegetable oils with different compositions and unsaturation degrees, namely soybean, hempseed, and linseed oils. Using terpenic comonomers such as limonene and β-myrcene allows one to prepare thermosets avoiding the traditional fossil-based diluents such as styrene, thus obtaining an outstanding gain in terms of both environmental and safety concerns. Furthermore, the materials obtained reveal tunable physical properties upon the proper choice of the monomers, with glass transition temperature ranging from 40 to 80 °C and Young’s modulus ranging from 200 to 1800 MPa. The possibility of preparing composite materials starting from the resins prepared in this way and natural fibres has also been explored due to the potential applications of bio-based composites in several industrial sectors.