Composite Biomaterials Research Articles

MECHANICAL PERFORMANCE AND WATER ABSORPTION OF COCONUT FIBER/POLYETHYLENE WASTE BIOCOMPOSITE PREPARED VIA A CHEMICAL-FREE APPROACH

Plastic wastes have caused serious environmental issues worldwide, and thus viable solutions for their replacement are now urgently needed. This work aimed to develop biocomposite materials based on polyethylene (PE) wastes as matrix reinforced with coconut fiber, without any additional chemical treatments, using extrusion and compression molding. The effects of polymer matrix type (high-density and low-density PE (HDPE and LDPE)) and fiber loading (5-15 wt%) on the mechanical properties and long-term water absorption behaviour of the materials were evaluated. Tensile strength results showed the optimum performance at 5 wt% fiber – of 16.6 MPa for the HDPE matrix and 7.3 MPa for the LDPE matrix, but flexural and impact strengths reduced with the fiber loading. An increasing trend of water absorption capacity was noted as a function of filler loading and of the water temperature during immersion, with a weight gain of up to 5%, following the trend: cold water > room temperature tap water > hot water. From the results, HDPE based biocomposites had better mechanical performance and lower water absorption capacity, compared with LDPE based biocomposites.

Environmental aging effects on mechanical behavior of an hemp based biocomposite material for structural strengthening

Biocomposites are innovative materials usually made of natural fibers embedded in a natural matrix. The mechanical behavior of such materials when exposed to the environmental agents (i.e. UV radiations, high/low temperature, variable humidity conditions) is a crucial issue. This paper is aimed to investigate an hemp based biocomposite for structural strengthening, addressing a gap in the existing literature concerning the mechanical characterization of the composite constituents (i.e. hemp ropes and natural matrices) under accelerated weathering conditions. In particular, this research involves the mechanical behavior assessment of hemp ropes, four distinct types of matrices (i.e. two organic binder based matrices and two mortar based matrices) and the hemp/matrix interface. Tensile tests, three point bending tests, uniaxial compression tests and pull-out tests are carried out to characterize these components. To simulate accelerated weathering, samples of the biocomposite constituents are subjected to cycles of hygrothermal stress and UV radiation using an accelerated weathering testing apparatus. Subsequently, experimental mechanical tests are performed on the aged biocomposite components, and their mechanical properties are assessed and compared to those of the non-aged materials. The results reveal that aging leads to a significant reduction in the mechanical properties of the hemp ropes, and varying effects on the mechanical properties of matrices depending on their nature (organic binder-based or mortar-based matrices).

Fabrication and characterization of sodium alginate-silicon nitride-PVA composite biomaterials with damping properties

Silicon nitride is utilized clinically as a bioceramic for spinal fusion cages, owing to its high strength, osteoconductivity, and antibacterial effects. Nevertheless, silicon nitride exhibits suboptimal damping properties, a critical factor in mitigating traumatic bone injuries and fractures. In fact, there is a scarcity of spinal implants that simultaneously demonstrate proficient damping performance and support osteogenesis. In our study, we fabricated a novel sodium alginate-silicon nitride/poly(vinyl alcohol) (SA-SiN/PVA) composite scaffold, enabling enhanced energy absorption and rapid elastic recovery under quasi-static and impact loading scenarios. Furthermore, the study demonstrated that the incorporation of physical and chemical cross-linking significantly improved stiffness and recoverable energy dissipation. Concerning the interaction between cells and materials, our findings suggest that the addition of silicon nitride stimulated osteogenic differentiation while inhibiting Staphylococcus aureus growth. Collectively, the amalgamation of ceramics and tough hydrogels facilitates the development of advanced composites for spinal implants, manifesting superior damping, osteogenic potential, and antibacterial properties. This approach holds broader implications for applications in bone tissue engineering.

Study on the characteristics of Napier grass fibre reinforced porcelain filler particulates poly lactic acid matrix biocomposite

This study investigates the complex properties of a novel biocomposite by a conventional process, which is composed of poly (lactic acid) (PLA) as the matrix, porcelain particles as fillers, and Napier grass fibre as reinforcement. The primary objective was to evaluate the mechanical, crystalline, water absorption, morphological, and antibacterial properties of the biocomposites in relation to the individual components and their synergistic impacts. When 25 g porcelain particles were added to PLA with Napier grass fibre, mechanical tests demonstrated a 25% increase in tensile strength (maximum tensile strength of 39.76 MPa) and a 30% increase in flexural strength (maximum flexural strength of 41.29 MPa). Scanning electron microscopy (SEM) revealed a strong interfacial bond between the fibre and matrix, with porcelain particles serving as bridges to facilitate stress transmission. The biocomposite exhibited reduced water absorption due to the inherent hydrophobic nature of porcelain, which enhances its resistance to bacterial growth. The study demonstrates that combining Napier grass fibre with porcelain filler particles synergistically enhances the properties of PLA, creating a viable biocomposite material suitable for use in packaging, automotive, and sustainable building industries.

Quantitative analysis of molecular interactions in κ-carrageenan-Isovanillin biocomposite for biodegradable packaging and pharmaceutical applications using NMR, TOF-SIMS, and XPS approach

This study explores the molecular interactions and structural changes in κ-carrageenan crosslinked with isovanillin to create a biocomposite material suitable for hard capsule and bio-degradable packaging applications. Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy revealed chemical changes in the conjugate molecule, indicating improved electronegativity due to intermolecular hydrogen bonding between κ-carrageenan and isovanillin. Time-of-flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis revealed enhanced ion intensity due to intermolecular interactions, particularly between sulphate and hydrogen ions. X-ray Photoelectron Spectroscopy (XPS) study demonstrated that κ-carrageenan and isovanillin form stronger hydrogen bonds, with a shift in binding energy indicating higher electronegativity. These findings shed light on the molecular mechanisms that underpin the formation of the biocomposite material, as well as its potential for use in hard capsule and biodegradable packaging materials, addressing the need for sustainable alternatives in the pharmaceutical and packaging industries while also contributing to environmental conservation.

Biocomposite thermoplastic polyurethanes containing evolved bacterial spores as living fillers to facilitate polymer disintegration

The field of hybrid engineered living materials seeks to pair living organisms with synthetic materials to generate biocomposite materials with augmented function since living systems can provide highly-programmable and complex behavior. Engineered living materials have typically been fabricated using techniques in benign aqueous environments, limiting their application. In this work, biocomposite fabrication is demonstrated in which spores from polymer-degrading bacteria are incorporated into a thermoplastic polyurethane using high-temperature melt extrusion. Bacteria are engineered using adaptive laboratory evolution to improve their heat tolerance to ensure nearly complete cell survivability during manufacturing at 135 °C. Furthermore, the overall tensile properties of spore-filled thermoplastic polyurethanes are substantially improved, resulting in a significant improvement in toughness. The biocomposites facilitate disintegration in compost in the absence of a microbe-rich environment. Finally, embedded spores demonstrate a rationally programmed function, expressing green fluorescent protein. This research provides a scalable method to fabricate advanced biocomposite materials in industrially-compatible processes.

A Revolution in Sustainable Development

The way we are currently developing our building structures is unsustainable, with a large amount of greenhouse gas (GHGs) emissions being a direct result of the production and implementation of the materials used in our buildings. The purpose of this honors thesis is to better understand the potential and feasibility of hemp biocomposite materials in construction. A case study will be examined, where a house plan will be taken, and utilized in two homes, one being constructed with conventional materials such as lumber, while the other with hemp biocomposites. Because the same house plan is used in both homes, we can objectively quantify the carbon footprint and monetary cost of both dwellings, and directly compare them. This side by side analysis can allow developers, architects, and hemp-based construction material companies to see the difference in cost and carbon footprint associated with switching to hemp biobased materials. Using professional journals, peer reviewed literature, and interviews with hemp companies, a building product analysis was conducted. This section shows the advantages and potential drawbacks of current building materials, and what are the benefits and drawbacks of transitioning towards hemp biocomposites. Through the building analysis and case study, this thesis is an extensive tool that shows the potential of hemp in future residential home construction. The carbon sequestered through hemp biocomposites is nearly double its conventional counterparts, and its higher cost can be justified as its benefits could be argued to outweigh the difference in total cost when it comes to the price of the home. For the full text, please visit https://scholar.colorado.edu/concern/undergraduate_honors_theses/rx913r48x.

Mechanical and radar absorption properties of sheep wool/epoxy composites

PurposeThe aim of this study is to determine the fracture behavior of wool felt and fabric based epoxy composites and their responses to electromagnetic waves.Design/methodology/approachNotched and unnotched tensile tests of composites made of wool only and hybridized with a glass fiber layer were carried out, and fracture behavior and toughness at macro scale were determined. They were exposed to electromagnetic waves between 8 and 18 GHz frequencies using two horn antennas.FindingsThe keratin and lignin layer on the surface of the wool felt caused lower values to be obtained compared to the mechanical values given by pure epoxy. However, the use of wool felt in the symmetry layer of the laminated composite material provided higher mechanical values than the composite with glass fiber in the symmetry layer due to the mechanical interlocking it created. The use of wool in fabric form resulted in an increase in the modulus of elasticity, but no change in fracture toughness was observed. As a result of the electromagnetic analysis, it was also seen in the electromagnetic analysis that the transmittance of the materials was high, and the reflectance was low throughout the applied frequency range. Hence, it was concluded that all of the manufactured materials could be used as radome material over a wide band.Practical implicationsSheep wool is an easy-to-supply and low-cost material. In this paper, it is presented that sheep wool can be evaluated as a biocomposite material and used for radome applications.Originality/valueThe combined evaluation of felt and fabric forms of a natural and inexpensive reinforcing element such as sheep wool and the combined evaluation of fracture mechanics and electromagnetic absorption properties will contribute to the evaluation of biocomposites in aviation.

Modern Technologies for Bone Defect Replacement (Literature Review)

Information is provided regarding the materials used to replace bone defects caused by gunshot wounds. Materials and various techniques for replacing bone defects of the limbs are described. Goal. Conduct an analysis of surgical technologies and materials for the replacement of bone defects, by analyzing literary sources. Methods. In three reputable databases (PubMed, Scopus, and Web of Science), an analysis of the latest scientific studies devoted to the treatment of defects of long tubular bones in the period from 2015 to 2022 was carried out. The search was carried out using the keywords "bone defects", "autograft", "allograft", "Ilizarov method", "Masquelet method", "biocomposite materials". The results. Analysis of osteoinductive and osteoconductive properties of auto- and allografts, modern biocomposite materials. Established advantages and disadvantages. The contemporary analysis of literary sources does not provide an objective comparative assessment of the effectiveness of the treatment of bone defects according to the Masquelet and Ilizarov method due to the lack of a sufficient number of randomized studies, which is the basis for further targeted research. Conclusions. Treatment of bone tissue defects of various genesis is an urgent problem of modern orthopedics and traumatology. The wide range of treatment options is proof that no single strategy works for every patient, just as there is no perfect universal material to fill and ensure bone regeneration in the defect site. A promising direction is the search for new or a combination of known materials and methods, which are able to maximally provide compensation for these pathological conditions.

Complexity biomechanics: a case study of dragonfly wing design from constituting composite material to higher structural levels.

Presenting a novel framework for sustainable and regenerative design and development is a fundamental future need. Here we argue that a new framework, referred to as complexity biomechanics, which can be used for holistic analysis and understanding of natural mechanical systems, is key to fulfilling this need. We also present a roadmap for the design and development of intelligent and complex engineering materials, mechanisms, structures, systems, and processes capable of automatic adaptation and self-organization in response to ever-changing environments. We apply complexity biomechanics to elucidate how the different structural components of a complex biological system as dragonfly wings, from ultrastructure of the cuticle, the constituting bio-composite material of the wing, to higher structural levels, collaboratively contribute to the functionality of the entire wing system. This framework not only proposes a paradigm shift in understanding and drawing inspiration from natural systems but also holds potential applications in various domains, including materials science and engineering, biomechanics, biomimetics, bionics, and engineering biology.

Enhancing Current Density and Specific Capacitance through Tensile TEMPO, Bacterial Cellulose and Polypirrole Nanocomposites

The researchers developed a bio-composite film material that serves as a substitute for metal. The materials used are TEMPO ((2,2,6,6-tetramethylpiperidine-1-oxyl)), Bacterial Cellulose, and Polypyrrole (Ppy). This research aimed to increase the material's current density and specific capacitance values using the drawing method. Composite nanomaterials are made by oxidizing BC (Bacterial Cellulose) with TEMPO. The resulting TOBC (TEMPO Bacterial Cellulose) material was mixed with Ppy using the in situ method. The mixture is then drawn wet—measurement of current density and capacitance using Cyclic Voltammetry (CV) Testing. The current density and specific capacitance results increased by 542.74% and 754.79% after drawing the nanocomposite material. It is directly proportional to the effects of characteristic testing, which includes SEM, XRD, and FTIR. As a result of the withdrawal of the polypyrrole, it will be more evenly distributed in the composite material, absorbing and coating the nata de coco. The researchers concluded that when the TOBC/Ppy fibers are straighter and denser, they achieve higher current density and capacitance values.

Natural Nano-Minerals (NNMs): Conception, Classification and Their Biomedical Composites.

Natural nano-minerals (NNMs) are minerals that are derived from nature with a size of less than 100 nm in at least one dimension in size. NNMs have a number of excellent properties due to their unique nanostructure and have been applied in various fields in recent years. They are rising stars in various disciplines, such as materials, biomedicine, and chemistry, taking advantage of their huge surface area, multiple active sites, excellent adsorption capacity, large quantity, low cost, and nontoxicity, etc. To provide a more comprehensive overview of NNMs and the biomedical applications of NNMs-based nanocomposites, this review classifies NNMs into three types by dimension, lists the structure and properties of typical NNMs, and illustrates their biomedical applications. Furthermore, a novel concept of natural nanomineral medical materials (NNMMs) is proposed, focusing on the medical value of NNMs. In addition, this review attempts to address the current challenges and delineate future directions for the advancement of NNMs. With the deepening of biomedical applications, it is believed that NNMMMs will inevitably play an important role in the field of human health and contribute to its promotion.

Production of Thermoplastic Composites reinforced with Posidonia Oceanica Fibers

This study investigates the development and characterization of a new biocomposite and biodegradable material based on natural fibers. This new biocomposite is composed of commercially available biodegradable polylactic acid (PLA) as a matrix and Posidonia Oceanica (PO) fibers collected from the coasts of Tunisia as reinforcement. This new material is produced by heating and pressing the two components in a special device. The use of PO, or sea balls, will allow exploiting one of the marine residues abundant on Tunisian beaches, instead of exploited industrially, and to preserve the beaches from debris given the impact of tourist activity in the Tunisian economy. The PLA/PO coupling allowed obtaining a biocomposite with promising mechanical properties. The improvement in maximum stress and strain after the addition of PO is one of the highlights of the results of this work.

Development and Characterization of a PLA Biocomposite reinforced with Date Palm Fibers

Despite the promising potential of bio-composites derived from plant fibers due to their ecological and economic benefits, challenges persist in their preparation, restricting their commercial applications. These challenges are primarily associated with developing suitable methods, acquiring appropriate equipment for treating plant fibers, and addressing the time constraints in preparation. This study aims to contribute to the development and characterization of a new biocomposite and biodegradable material based on natural fibers produced through hot compression. The newly developed biocomposite comprises commercial biodegradable poly-lactic acid (PLA) as a matrix and untreated fiber fabric extracted from date palms as reinforcement. The use of untreated fiber fabric has successfully overcome the preparation difficulties. Experimental results on the new biocomposite reveal the strong adhesion between its fibers and the matrix, emphasizing the significant impact of choosing the right manufacturing conditions on the developed mechanical properties.

Composite PCL Scaffold With 70% β-TCP as Suitable Structure for Bone Replacement

The purpose of this work was to optimise printable polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP) biomaterials with high percentages of β-TCP endowed with balanced mechanical characteristics to resemble human cancellous bone, presumably improving osteogenesis. PCL/β-TCP scaffolds were obtained from customised filaments for fused deposition modelling (FDM) 3D printing with increasing amounts of β-TCP. Samples mechanical features, surface topography and wettability were evaluated as well as cytocompatibility assays, cell adhesion and differentiation. The parameters of the newly fabricated materila were optimal for PCL/β-TCP scaffold fabrication. Composite surfaces showed higher hydrophilicity compared with the controls, and their surface roughness sharply was higher, possibly due to the presence of β-TCP. The Young's modulus of the composites was significantly higher than that of pristine PCL, indicating that the intrinsic strength of β-TCP is beneficial for enhancing the elastic modulus of the composite biomaterials. All novel composite biomaterials supported greater cellular growth and stronger osteoblastic differentiation compared with the PCL control. This project highlights the possibility to fabricat, through an FDM solvent-free approach, PCL/β-TCP scaffolds of up to 70 % concentrations of β-TCP. overcoming the current lmit of 60 % stated in the literature. The combination of 3D printing and customised biomaterials allowed production of highly personalised scaffolds with optimal mechanical and biological features resembling the natural structure and the composition of bone. This underlines the promise of such structures for innovative approaches for bone and periodontal regeneration.

Bioengineered cell-constructs using decellularized fish skin-based composite bioink for regenerating muscle tissue

A biocomposite for enhancing muscle tissue regeneration was introduced using decellularized fish skins. Decellularized tilapia and cod skin were explored as constituents of the composite and compared with the conventionally used decellularized extracellular matrix (dECM) derived from porcine skin tissue. As a cell-laden bioink for 3D bioprinting, the choice of tilapia skin dECM, which possesses remarkable printability, allows for precise three-dimensional (3D) structure fabrication. Meanwhile, cod skin dECM was selected as the dispersed phase for enhancing biological activities because of its omega-3 unsaturated fatty acid, which is known to promote angiogenesis and is crucial for nutrient supply during tissue regeneration and lower inflammation. Through meticulous compositional optimization of the fish skin dECMs, efficient printability and high myogenic activity of the fish skin dECM composite were attained. In vitro evaluations using adipose stem cells clearly demonstrated the support of the cell-laden composite bioink for myogenesis, as determined by various cellular activities, including myogenic genes, compared to those of the porcine-based dECM bioink. The regenerative potential of the composites was validated using an in vivo mouse model of volumetric muscle loss. Based on these results, this study provides valuable insights into the use of decellularized fish skin as composite biomaterials and demonstrates their distinct advantages in muscle tissue engineering, in terms of both printability and bioactivity induction.

Expanded Perlite Mineral As a Natural Additive Used In Polylactide-Based Biodegradable Composites

Polylactide (PLA) is a biodegradable polymer derived from natural resources used in various applications ranging from medical to packaging. In this study, biocomposites were developed by combining perlite mineral (PER), a natural filler material, with a biodegradable PLA matrix in incorporated contaminations of 2.5%, 5%, 10%, and 15%. The purpose of this work is to obtain composites having low production costs while retaining their main properties. Mixing force measurements, tensile, Shore hardness, impact tests, melt flow indices (MFI), and scanning electron microscopy (SEM) evaluations were carried out on composite samples to determine the processing, mechanical, melt flow, and morphological aspects of the developed composites. When the tensile test data were reviewed, minor decreases in the tensile strength and % elongation parameters were noticed with perlite loadings. The inclusion of perlite powder significantly reduced the impact strength value of PLA. Composites with high amounts of PER displayed elevated hardness values. While the MFI results were analyzed, it was deduced that the addition of PER increased the melt flow characteristics of the PLA polymer. At low PER quantities, SEM micrographs displayed that PER particles were homogeneously distributed in the PLA phase. The particle homogeneity in the composite morphology deteriorated as the PER loading ratio in the composites rose. According to the overall results, the highest performance among composites was achieved in the sample including 2.5% PER, and this sample was considered to be the most suitable option for applications regarding PLA-based biocomposite material purposes.

Exploring the Untapped Potential of Pine Nut Skin By-Products: A Holistic Characterization and Recycling Approach.

The increasing population, food demand, waste management concerns, and the search for sustainable alternatives to plastic polymers have led researchers to explore the potential of waste materials. This study focused on a waste of pine nut processing referred to in this paper as pine nut skin. For the first time, its nutritional profile, potential bioactive peptide, contaminants, and morphological structure were assessed. Pine nut skin was composed mainly of carbohydrates (56.2%) and fiber (27.5%). The fat (9.8%) was about 45%, 35%, and 20% saturated, monounsaturated, and polyunsaturated fatty acid, respectively, and Omega-9,-6, and -3 were detected. Notably, oleic acid, known for its health benefits, was found in significant quantities, resembling its presence in pine nut oil. The presence of bioactive compounds such as eicosapentaenoic acid (EPA) and phytosterols further adds to its nutritional value. Some essential elements were reported, whereas most of the contaminants such as heavy metals, polycyclic aromatic hydrocarbons, rare earth elements, and pesticides were below the limit of quantification. Furthermore, the in silico analysis showed the occurrence of potential precursor peptides of bioactive compounds, indicating health-promoting attributes. Lastly, the morphological structural characterization of the pine nut skin was followed by Fourier Transform Infrared and solid-state NMR spectroscopy to identify the major components, such as lignin, cellulose, and hemicellulose. The thermostability of the pine nut skin was monitored via thermogravimetric analysis, and the surface of the integument was analyzed via scanning electron microscopy and volumetric nitrogen adsorption. This information provides a more comprehensive view of the potential uses of pine nut skin as a filler material for biocomposite materials. A full characterization of the by-products of the food chain is essential for their more appropriate reuse.

Tribological behavior of silver-doped eggshell-derived hydroxyapatite reinforcement in PMMA-based composite

Polymethylmethacrylate (PMMA) and hydroxyapatite (HAp) are the two most promising biocompatible materials used in biomedical applications. The current research performs the wettability and tribological characterization of the novel hybrid biocomposite of PMMA reinforced with eggshell-derived, silver-doped hydroxyapatite (HAPAg). Varying wt% of HAPAg in PMMA were analyzed using a ball-on-disk tribometer. The coefficient of friction shows an increasing trend with an increase in normal load for all the compositions while, with reinforcement of HAPAg, it increases till 5 wt% and then shows a sudden decrement at PHA7.5 due to the formation of flattened asperities at the contact surface. However, the progressive increase in hardness with the inclusion of HAPAg in PMMA correlates with the reduction in the wear rate of the composite samples. The highest wear rate was observed for PHA0 (i.e. 862.42 × 10−5 mm3/m) at 60 N. As observed, the hydrophilicity increases (contact angle changed from 96.30° ± 2.11° [PHA0] to 81.70° ± 1.01° [PHA7.5]), and the porosity decreases (≈2.86%) with the reinforcement of HAPAg in PMMA which further improves the cohesion strength and microhardness of the composite material. The X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis confirms the uniform reinforcement of HAPAg, and the worn surface behavior was inspected using scanning electron microscopy, Stereo zoom microscope, and three-dimensional surface profilometer. The low-specific wear characteristic at higher loads ensures the application of developed biocomposite material in dental and orthopedic applications.

Modelling of hybrid biocomposites for automotive structural applications

The demand for environmentally friendly materials is at its peak, and government legislations have become stricter and no longer tolerate violations. With biocomposites emerging as structural components instead of being hidden as non-structural applications and interiors, the automotive and motorsport sector started considering them for structural body parts. Natural fibres abundance, commercial availability, renewability, low density, low cost, and high tensile strength make biocomposite materials excellent candidates for eco-friendly vehicles. Several studies reported the utilisation of biocomposites as high-performance components and structural applications. However, current computer-aided engineering and modelling tools are insufficient to explore the vast field of possibilities during biocomposite materials selection to accurately predict the components' behaviour and analyses. Therefore, this study focuses on creating a material model to predict the behaviour of biocomposite materials. Additionally, the model is numerically implemented to illustrate the deformation and bending stiffness capabilities of a motorsport monocoque chassis structure application. A micromechanics modelling combining rate-dependant constitutive laws and multi-site interactions of inclusions is developed for studying the nonlinear response of composite materials. To avoid numerical instabilities when increments of time become very small, a regulation procedure concerning the visco-plastic function is adopted in the computation of the consistent tangent modulus. Based on the Generalised Mori–Tanaka (GMT) scheme, the effective properties are obtained for the nonlinear composite. The accuracy of the model is evaluated and validated by comparison results from the open literature. Finally, the developed constitutive equations are implemented as a user-defined material UMAT in a Finite Element code, leading to an application on a bio-based composite for the bamboo/flax fibre-reinforced epoxy hybrid composite materials.