Sustainable Biocomposites Materials for Automotive Brake Pad Application:An Overview

Research into converting waste into viable eco-friendly products has gained global concern.Using natural fibres and pulverized metallic waste becomes necessary to reduce noxious environmental emissions due to indiscriminately occupying the land.This study reviews the literature in the broad area of green composites in search of materials that can be used in automotive brake pads.Materials made by biocomposite,rather than fossil fuels,will be favoured.A database containing the tribo-mechanical performance of numerous potential components for the future green composite was established using the technical details of bio-polymers and natural reinforcements.The development of materials with diverse compositions and varying proportions is now conceivable,and these materials can be permanently connected in fully regulated processes.This explanation demonstrates that all of these variables affect friction coefficient,resistance to wear from friction and high temperatures,and the operating life of brake pads to varying degrees.In this study,renewable materials for the matrix and reinforcement are screened to determine which have sufficient strength,coefficient of friction,wear resistance properties,and reasonable costs,making them a feasible option for a green composite.The most significant,intriguing,and unusual materials used in manufacturing brake pads are gathered in this review,which also analyzes how they affect the tribological characteristics of the pads.

Development and Characterization of Calcium Based Biocomposites Using Waste Material (Calcite Stones) for Biomedical Applications

Calcium-based biocomposite materials have a pivotal role in the biomedical field with their diverse properties and applications in combating challenging medical problems. The study states the development and characterization of Calcium-based biocomposites: Hydroxyapatite (HAP), and PVA-Gelatin-HAP films. For the preparation of Calcium-based biocomposites, an unconventional source, the waste material calcite stone, was used as calcium raw material, and by the process of calcination, calcium oxide was synthesized. From calcium oxide, HAP was prepared by chemical precipitation method, which was later added in different proportions to PVA-Gelatin solution and finally dried to form biocomposite films. Then the different properties of PVA/Gelatin/HAP composite, for instance, chemical, mechanical, thermal, and swelling properties due to the incorporation of various proportions of HAP in PVA-Gelatin solution, were investigated. The characterization of the HAP was conducted by X-ray Diffraction Analysis, and the characterization of HAP-PVA-Gelatin composites was done by Fourier Transform Infrared Spectroscopy, Thermomechanical Analysis, Tensile test, Thermogravimetric Differential Thermal Analysis, and Swelling Test. The produced biocomposite films might have applications in orthopedic implants, drug delivery, bone tissue engineering, and wound healing.

Characterization of Formacell Lignin Derived from Black Liquor as a Potential Green Additive for Advanced Biocomposites

Black liquor is obtained as a by-product of the pulping process,which is used to convert biomass into pulp by removing lignin,hemicelluloses and other extractives from wood to free cellulose fibers.Lignin represents a major constituent in black liquor,with quantities varying from 20%to 30%,of which a very low share is used for manufacturing value-added products,while the rest is mainly burned for energy purposes,thus underestimating its great potential as a raw material.Therefore,it is essential to establish new isolation and extraction methods to increase lignin valorization in the development of bio-based chemicals.The aim of this research work was to determine the effect of KOH or ethanol concentration as an isolation agent on lignin yields and the chemical characteristics of lignin isolated from formacell black liquor of oil palm empty fruit bunch(OPEFB).Isolation of lignin was carried out using KOH with various concentrations ranging from 5%to 15%(w/v).Ethanol was also used to precipitate lignin from black liquor at concentrations varying from 5%to 30%(v/v).The results obtained showed that the addition of KOH solution at 12.5%and 15%concentrations resulted in better lignin yield and chemical properties of lignin,i.e.,pH values of 3.86 and 4.27,lignin yield of 12.78%and 14.95%,methoxyl content of 11.33%and 10.13%,and lignin equivalent weights of 476.25 and 427.03,respectively.Due to its phenolic structure and rich functional groups that are favorable for modifications,lignin has the potential to be used as a green additive in the development of advanced biocomposite products in various applications to replace current fossil fuel-based material,ranging from fillers,fire retardants,formaldehyde scavengers,carbon fibers,aerogels,and wood adhesives.

Fabrication and characterization of 3D printed biocomposite scaffolds based on PCL and zirconia nanoparticles

The application of three-dimensional printed polymer scaffolds in repairing bone defects is a promising strategy.Among them,polycaprolactone(PCL)scaffolds are widely studied due to their good processability and controlled degradation rate.However,as an alternative graft for repairing bone defects,PCL materials have poor hydrophilicity,which is not conducive to cell adhesion and growth.In addition,the poor mechanical properties of PCL materials cannot meet the strength required to repair bone defects.In this paper,nano-zirconium dioxide(ZrO2)powder is embedded in PCL material through a meltmixing process,and a regular grid scaffold is constructed by 3D printing.The embedding of nanometer zirconium dioxide powder improves the hydrophilicity and water absorption of the composite scaffold,which is conducive to cell adhesion,proliferation and growth and is beneficial to the exchange of nutrients.Therefore,the PCL/ZrO2 composite scaffold showed better biological activity in vitro.At the same time,the PCL/ZrO2 composite material system significantly improves the mechanical properties of the scaffold.Among them,compared with the pure PCL scaffold,the Young’s modulus is increased by about 0.4 times,and the compressive strength is increased by about 0.5 times.In addition,the osteogenic differentiation results also showed that the PCL/ZrO2 composite scaffold group showed better ALP activity and more effective bone mineralization than the pure PCL group.We believe that the 3D printed PCL/ZrO2 composite scaffold has certain application prospects in repairing bone defects.

Performance of Unidirectional Biocomposite Developed with Piptadeniastrum Africanum Tannin Resin and Urena Lobata Fibers as Reinforcement

The Piptadeniastrum Africanum bark tannin extract was characterized using MALDI TOF,ATR-FT MIR.It was used in the development of a resin with Vachellia nilotica extract as a biohardener.This tannin is consisting of Catechin,Quercetin,Chalcone,Gallocatechin,Epigallocatechin gallate,Epicatechin gallate.The gel time of the resin at natural pH(pH=5.4)is 660 s and its MOE obtained by thermomechanical analysis is 3909 MPa.The tenacity of Urena lobata fibers were tested,woven into unidirectional mats(UD),and used as reinforcement in the development of biocomposite.The fibers tenacity at 20,30 and 50 mm lengths are respectively 65.41,41.04 and 33.86 cN·Tex^(−1).The UD biocomposite obtained had very interesting mechanical properties.Its density,tensile MOE,ultimate strength,bending MOE and MOR are respectively 926 kg·m^(−3),6 GPa,55 MPa,9.3 GPa and 68.3 MPa.This biocomposite can be used in a building exterior structure.

Novel Mycelium-Based Biocomposites (MBB) as Building Materials

Novel mycelium-based biocomposites(MBB)were obtained from local agricultural(hemp shives)and forestry(wood chips)by-products which were bounded together with natural growth of fungal mycelium.As a result,hemp mycocomposites(HMC)and wood mycocomposites(WMC)were manufactured.Mechanical,water absorption and biodegradation properties of MBB were investigated.MBB were characterized also by ash content and elemental composition.The results of MBB were compared with the reference materials such as the commercial MBB material manufactured by Ecovative®Design(EV),hemp magnesium oxychloride concrete(HC)and cemented wood wool panel(CW),manufactured by CEWOOD®.The mechanical properties of HMC and WMC showed that the bending strength difference was about 30%,with a better result for HMC.Compression strength was better for WMC by about 60%compared to that of HMC.The mechanical strength of HMC and HC materials was equal;both materials contained hemp shives but differed by the binding material.Water absorption and volumetric swelling tests showed that HMC and WMC could be considered as potential biosorbents.Ash content and elemental analysis showed that reference materials(CW,HC)contained significant amounts of inorganic compounds that decreased the biodegradation rate,compared to the case of HMC and WMC materials.The biodegradation results of HMC and WMC,after 12 weeks,revealed a mass loss(ML)above 70%,while in the case of EV,HC and CW,it was about 60%,17%and only 6%,respectively.MBB were completely biodegradable.

Synthesis and Structural Characterization of Hydroxyapatite-Wollastonite Biocomposites, Produced by an Alternative Sol-Gel Route

Hydroxyapatite is a type of calcium phosphate-based material with great interest for biomedical applications, due to the chemical similarity between this material and the mineral part of human bone. However, synthetic hydroxyapatite is essentially brittle;the practice indicates that the use of hydroxyapatite without additives for implant production is not efficient, due to its low strength parameters. In the present work, biocomposites of hydroxyapatite-wollastonite were synthesized by an alternative sol-gel route, using calcium nitrate and ammonium phosphate as precursors of hydroxyapatite, and high purity natural wollastonite was added in ratios of 20, 50 and 80 percent by weight immersed in aqueous medium. Formation of hydroxyapatite occurs at a relatively low temperature of about 350?C, while the wollastonite remains unreacted. After that, these biocomposites were sintered at 1200?C for 5 h to produce dense materials. The characterization techniques demonstrated the presence of hydroxyapatite and wollastonite as unique phases in all products.

Chitosan/Nanocrystalline Cellulose Biocomposites Based on Date Palm (Phoenix Dactylifera L.) Sheath Fibers

In this study,nanocrystalline celluloses were used to enhance physical,mechanical and water vapor barrier properties of chitosan films for potential food packaging applications.Two different mineral acids(sulfuric and phosphoric)were used to extract nanocrystalline cellulose from date palm sheath fibers.The influence of cellulose I and cellulose II on the properties of the isolated nanocrystalline celluloses(e.g.,yield,energy and length of intra-and intermolecular hydrogen bonds,and degree of substitution)were studied too.The characteristics of chitosan biocomposite film with phosphorylated nanocrystalline cellulose were compared to those with sulfated nanocrystalline cellulose.Results showed that besides cellulose polymorphism,the ionic ester groups on the surface of nanocrystalline cellulose is one of the factors influencing the physical,chemical,mechanical,and water vapor barrier properties in chitosan/nanocrystalline cellulose biocomposites.

Nano-apatite/Polymer Biocomposite for Tissue Engineering

A new kind of tissue engineering scaffold materials of nano-apatite （ NA ） and polyamide6 （ PA6 ） biocomposite was prepared by means of the co-solution method. The NA crystals uniforndy distribute in the composite with a size of 10-30 nm in diameter by 50-90 nm in length. The NA/ PA6 composite has good homogeneity and high NA content, and excellent mechanical properties close to those of natural bone. The porous 3-D scaffold has not only macropores, but also micropores on the walls of macropores with porosity of about 80% and the size of pore diameter of about 300μm made by injection foam. The biocomposite can be used for bone repair and as scaffolds in tissue engineering.

Reactive Compatibilization of Short-Fiber Reinforced Poly(lactic acid)Biocomposites

Poor interfacial adhesion between biobased thermoplastics and natural fibers is recognized as a major drawback for biocomposites.To be applicable for the large-scale production,a simple method to handle is of importance.This work presented poly(lactic acid)(PLA)reinforced with short-fiber and three reactive agents including anhydride and epoxide groups were selected as compatibilizers.Biocomposites were prepared by one-step meltmixing methods.The influence of reactive agents on mechanical,dynamic mechanical properties and morphology of PLA biocomposites were investigated.Tensile strength and storage modulus of PLA biocomposites incorporated with epoxide-based reactive agent was increased 13.9%and 37.4%compared to non-compatibilized PLA biocomposite,which was higher than adding anhydride-based reactive agent.SEM micrographs and Molau test exhibited an improvement of interfacial fiber-matrix adhesion in the PLA biocomposites incorporated with epoxide-based reactive agent.FTIR revealed the chemical reaction between the fiber and PLA with the presence of epoxide-based reactive agents.

Influence of Glycerol Content on Properties of Wheat Gluten/Hydroxyethyl Cellulose Biocomposites

Environmentally friendly biocomposites were prepared by blending wheat gluten（WG）as a matrix, hydroxyethyl cellulose（HEC）as a filler,and glycerol as a plasticizer,followed by thermo-molding of the mixture at 120°C for crosslinking the matrix.Moisture absorption,tensile properties,dynamic mechanical analysis,and dynamic rheology were evaluated in relation to the glycerol content.Tensile strength and modulus drop dramatically with increasing glycerol content,which is accompanied by significant depression in the glass transition temperature and improvement in the extensibility of the biocomposites.

Hybrid Method for the Formation of Biocomposites on the Surface of Stainless Steel Implants

This study reports a hybrid method which allows the formation of biocomposites on stainless steel implants. The main idea of the method is to create multilayer coatings consisting of titanium primer layer and a microarc calcium-phosphate coating. The titanium layer is deposited from plasma of continuous vacuum-arc discharge, and calcium-phosphate coating is formed by the microarc oxidation technique. The purpose of the hybrid method is to combine the properties of good strength stainless steel with high bioactivity of calcium-phosphate coating. This paper describes the chemical composition, morphology characteristics, adhesion and the ability of the formed biocomposites to stimulate the processes of osteoinduction. It is expedient to use such biocomposites for implants which carry heavy loads and are intended for long-term use, e.g. total knee endoprosthesis.

Study of the Thermal, Rheological, Morphological and Mechanical Properties of Biocomposites Based on Rod-Of Typha/HDPE Made up of Typha Stem and HDPE

The thermal, rheological and morphological properties of composite biomaterials made with mixture of high density polyethylene and typha rod powder (RD) were evaluated. The dynamic mechanical behavior of the samples was studied with 25%, 35% and 45% typha stem powder concentrations. The viscoelastic properties are mainly related to the nature of the polymer and the typha stem powder. Storage (G') and loss (G') moduli increased significantly, depending on the amount of powder in the molten mixture. After a viscosity increase was noticed in low frequency, it decreased in high frequencies, which demonstrates the pseudo-plasticity effect. Morphological and thermal characterization results have shown the dispersion state of the powder and its ability to modify the kinetics crystallization of biocomposites.

Preparation and Characterization of Raw and Chemically Modified Sponge-Gourd Fiber Reinforced Polylactic Acid Biocomposites

This research work has been undertaken to fabricate environmentally friendly biocomposites for biomedical and household applications. Sponge-gourd fibers (SGF) obtained from Luffa cylindrica plant were chemically treated separately using 5 and 10 wt% NaOH, acetic anhydride and benzoyl chloride solutions. SGF reinforced polylactic acid (PLA) biocomposites were fabricated using melt compounding technique. Surface morphological, structural, mechanical and thermal properties, as well as antibacterial activities of raw and chemically modified SGF reinforced PLA (SGF-PLA) composites were characterized by field emission scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometry, universal testing method, thermogravimetry, and Kirby-Bauer agar diffusion method, respectively. Surface morphology indicates that after treatment of fibers, the interfacial adhesion between PLA and fibers is improved. X-ray diffractometry result shows that chemical treatment of fibers improves the crystallinity and exhibits new chemical bond formation in the composites. After chemical treatment, compressive strength of the composites is found to increase by 10% - 35%. The thermal stability of the treated fiber reinforced composites is also found to increase significantly. The composites have no antibacterial activities and no cytotoxic effect on non-cancer cell line. Soil burial test has confirmed that the composites are biodegradable. Benzoyl chloride treatment of fibers shows superior mechanical properties and enhances thermal stability among the composites.

Recent advances in functional utilisation of environmentally friendly and recyclable high-performance green biocomposites: A review

Humans have relied on biomass for survival and development since the Stone Age. All aspects of human needs for materials are covered by tools, fuel, and buildings. Nowadays, metals and petroleum-based materials are widely used in highly developed industries. Unfortunately, environmental contamination and the loss of natural resources have led to the reemergence of biomass resources as efficient and sustainable energy sources. Notably, simple and direct applications can no longer meet the demand for functionalization, high performance of materials and construction materials. Therefore, it is imperative to modify biomass and combine its utilisation to produce functionalization and high performance materials. For example, construction materials with superior mechanical properties and water resistance can be produced by reinforcing fibres to facilitate crosslinking. Water-oil separation or adsorption effects of hydrogels and aerogels are determined by the porosity and lightness of biomass, biocomposite conductor is prepared by chimaeric conductive material. Here, we review the approaches that have been taken to devise an environmentally friendly yet fully recyclable and sustainable functionalised biocomposites from biomass and its potential directions for future research.

Novel hybrid biocomposites for tendon grafts:The addition of silk to polydioxanone and poly(lactide-co-caprolactone)enhances material properties,in vitro and in vivo biocompatibility

Biopolymers play a critical role as scaffolds used in tendon and ligament(TL)regeneration.Although advanced biopolymer materials have been proposed with optimised mechanical properties,biocompatibility,degradation,and processability,it is still challenging to find the right balance between these properties.Here,we aim to develop novel hybrid biocomposites based on poly(p-dioxanone)(PDO),poly(lactide-co-caprolactone)(LCL)and silk to produce high-performance grafts suitable for TL tissue repair.Biocomposites containing 1-15%of silk were studied through a range of characterisation techniques.We then explored biocompatibility through in vitro and in vivo studies using a mouse model.We found that adding up to 5%silk increases the tensile properties,degradation rate and miscibility between PDO and LCL phases without agglomeration of silk inside the composites.Furthermore,addition of silk increases surface roughness and hydrophilicity.In vitro experiments show that the silk improved attachment of tendon-derived stem cells and proliferation over 72 h,while in vivo studies indicate that the silk can reduce the expression of pro-inflammatory cytokines after six weeks of implantation.Finally,we selected a promising biocomposite and created a prototype TL graft based on extruded fibres.We found that the tensile properties of both individual fibres and braided grafts could be suitable for anterior cruciate ligament(ACL)repair applications.

Developing a TRL-oriented roadmap for the adoption of biocomposite materials in the construction industry

The construction industry is a major contributor to environmental pollution.The effect of the construction industry on the environment may be mitigated using eco-friendly construction materials,such as biocomposites.Once developed,biocomposites may offer a viable alternative to the current materials in use.However,biocomposites are lagging in terms of adoption and eventual use in the construction industry.This article provides insights into the steps for biocomposites to become a product that is ready to use by the construction industry in a structural role.The development and the adoption of such a material is tackled with the use of two concepts,i.e.,technology readiness level and roadmapping,and explored in a case study on the“liquid wood”.Furthermore,interviews in the construction industry are carried out to identify the industry’s take on biocomposites.A customized roadmap,which underlines a mostly nontechnical perspective concerning this material,has emerged.Additionally,the adoption and diffusion issues that the“liquid wood”may encounter are outlined and complemented with further recommendations.

Valorization of Tree Bark-Derived Suberin in Applications for the Bio-Based Composites Industry–A Recent Review

Bark extracts are sustainable sources of biopolymers and hold great promise for replacing fossil fuel-based polymers,for example,in wood-based composites.In addition to primary and secondary metabolites,tree bark also contains suberin,which plays a major role in protecting the tree from environmental conditions.Suberin is a natural aliphatic-aromatic cross-linked polyester present in the cell walls of both normal and damaged external tissues,the main component of which are long-chain aliphatic acids.Its main role as a plant ingredient is to protect against microbiological factors and water loss.One of the most important suberin monomers are suberin fatty acids,known for their hydrophobic and barrier properties.Therefore,due to the diverse chemical composition of suberin,it is an attractive alternative to hydrocarbon-based materials.Although its potential is recognized,it is not widely used in biocomposites technology,including wood-based composites and the polymer industry.The article will discuss the current knowledge about the potential of suberin and its components in biocomposites technology,which will include surface finishes,composite adhesives and polymer blends.

Nano-SiC reinforced Zn biocomposites prepared via laser melting:Microstructure,mechanical properties and biodegradability

Zn has been regarded as new kind of potential implant biomaterials due to the desirable biodegradability and good biocompatibility,but the low strength and ductility limit its application in bone repairs.In the present study,nano-SiC was incorporated into Zn matrix via laser melting,aiming to improve the mechanical performance.The microstructure analysis showed that nano-SiC distributed along Zn grain boundaries.During the laser rapid solidification,nano-SiC particles acted as the sites for heterogeneous nucleation,which resulted in the reduction of Zn grain size from 250μm to 15μm with 2 wt%SiC(Zn-2 SiC).Meanwhile,nano-SiC acted as a reinforcer by virtue of Orowan strengthening and dispersion strengthening.As a consequence,the nanocomposites showed maximal compressive yield strength(121.8±5.3 MPa)and high microhardness(72.24±3.01 HV),which were increased by 441%and 78%,respectively,compared with pure Zn.Moreover,fracture analysis indicated a more ductile fracture of the nanocomposites after the incorporation of nano-SiC In addition,the nanocomposites presented favorable biocompatibility and accelerated degradation caused by intergranular corrosion.These findings suggested that the nano-SiC reinforced Zn biocomposites may be the potential candidates for orthopedic implants.

A Comparison between Sabra and Alfa Fibers in Rubber Biocomposites

The main objective of this investigation is to valorize a Moroccan crop residue(Sabra fibers,Agave Americana L.)and to compare with Alfa fibers(,Stipa tenacissima L.)as reinforcement in an elastomeric matrix in term of the relaxation properties,mechanical and rheological properties.The preparation and properties of these two natural fibers embedded in Styrene-Butadiene Rubber(SBR)are presented with and without the addition of Styrene-Ethylene-Butadiene-Styrene grafted with Maleic Anhydride(SEBS-g-MA)as a coupling agent.Five different series(SBR,SBR/Alfa,SBR/Alfa/SEBS,SBR/Sabra and SBR/Sabra/SEBS)were compounded by extrusion and compression molding.As a result,the addition of the coupling agent in the elastomeric matrix improves the relaxation properties,mechanical and rheological properties.Moreover,Sabra fibers show the good results compared to Alfa fibers.Finally,the Zener model was used to determine the rheological time response of the composites.A good agreement between the experimental data and the model was observed(R^2=0.99).