Sustainable Polymer Composites Research Articles

Plant Fiber Reinforced Polymeric Composites for Engineering Applications: A Review

Purpose: Scientists are looking for unconventional materials to achieve sustainable goals and reduce the consumption of non-renewable resources. This review focuses on polymeric composite materials with improved properties and low cost, synthesized from plant fibres and their potential fields of application. Theoretical Framework: Natural fibers, which are globally accessible, play a crucial role in improving thermal and mechanical properties when incorporated into polymers. With remarkable stiffness-density, strength and lightness, fibers stand out as promising, low-cost composite materials for applications in various areas of engineering. The plant diversity of the Amazon makes Brazil one of the largest global producers of natural fibers, providing an opportunity to develop new sustainable technologies. Method/Design/approach: Systematic literature review addressing potential applications of polymeric materials with plant fibers, fiber extraction methods, influence of fiber surface treatments and composite processing, and mechanical properties of polymeric composites with fibers. Results: Polymer composites reinforced with natural fibers are emerging as sustainable alternatives to synthetic materials, driven by their ecological nature, easy availability, low cost and biodegradability. A systematic review of the literature revealed that the mechanical properties of these composites are intrinsically linked to various factors, such as fibre orientation and length, which require careful optimization. In addition, it was observed that surface treatments, such as chemical acetylation and alkaline treatments, play a crucial role in improving the properties of plant fiber reinforced materials. These processes are responsible for removing impurities present in the cell walls of the fibers, such as lignins, waxes and hemicellulose, among others. Given Brazil's significant potential in the production of natural fibers, their application in industrial contexts is promising, offering an environmentally friendly solution for waste management. Thus, it is believed that, in the future, plant fibers will gain even more prominence, possibly effectively replacing the synthetic fibers widely used in the market. Research implications: This work contributes to the development of innovative, low-cost, sustainable materials, capable of minimizing the consumption of non-renewable resources and with potential applicability. Originality/value: The results are promising for the development of environmentally sustainable polymer composites with plant fibers, with wide applications in engineering.

An algae-derived partially renewable epoxy resin formulation for glass fibre-reinforced sustainable polymer composites

A brown algae-based renewable epoxy monomer can outperform bisphenol-A based epoxy resin and composite systems by means of thermomechanical properties.

Mechanical properties and tribological performance of polyoxymethylene/short cellulose fiber composites

Natural fibers are promising bio-based materials to use as reinforcements in polymer composites as often more affordable and accessible alternatives to fossil-based fibers, especially because of their superior sustainability. Polyoxymethylene (POM) is a widely used engineering thermoplastic, which has a melting temperature suitable for processing with natural fibers. In this study, such composites consisting of POM and regenerated cellulose fibers have been developed and studied in terms of their mechanical, thermal, tribological and structural properties. Tensile and flexural moduli increased with incorporation of 30 wt% fibers up to 89% and 79% respectively, crystallinity increased as well by a maximum of approx. 11% at 30% fiber content. Furthermore, the specific wear rate was improved for the composite with 10 wt% fibers, showing a decrease of roughly 80%. This study investigates the processing parameters and tribo-mechanical performance of POM-based natural fiber composites as an important route towards future sustainable polymer composites in load bearing applications.

Rubber wastes recycling for developing advanced polymer composites: A warm handshake with sustainability

Recycling and management of rubber wastes experiences an early-stage maturity in the quest for sustainable and circular materials. Up to now, solutions proposed for sustainable development of rubber wastes are limited, so that properties and performance features of recycled products are inadequate for practical applications. Herein, an experimental protocol is introduced for manufacturing semi-sustainable polymer composites based on ground tire rubber (GTR) and ethylene-vinyl acetate copolymer (EVA), varying carbon black (CB) content (5–50 phr), CB type, i.e., low-surface area CB (L-CB) and high-surface area CB (H-CB), and EVA/GTR composition (50/50 and 75/25 w/w). Processing (printability potential and fluidity/flexibility), properties (thermal, and mechanical), and performance (fire safety and electrical conductivity) features of the resulting composites are analyzed and interpreted. Highly-loaded 50/50 GTR/EVA systems reveal promising properties and performance. The flexibility of product is promising for additive manufacturing. Tensile strength is independent from CB type and blend composition, while elongation at break change pursuing a percolation threshold for CB ≤ 10 phr and CB > 10 phr depending on CB type. Thermal stability is considerable for 50/50/50 (w/w)/phr GTR/EVA/CB system with high amount of GTR. A long-standing flame retardancy is observed for 50/50/50 GTR/EVA/L-CB and 50/50/25 GTR/EVA/H-CB (w/w)/phr composites. A frequency-independent direct current (DC) branch is appeared by increasing temperature at low-frequency region, characteristic of rubber-like dielectric materials. The DC part is intensified even at low temperatures (<10 °C) when CB content increased, so that percolation thresholds are 5 phr and 10 phr for H-CB and L-CB loaded blends, respectively. This work opens new gates of hope towards development of fully sustainable polymer composites from recycled rubber wastes.

High Value-Added Reutilization of Waste-Printed Circuit Boards Non-Metallic Components in Sustainable Polymer Composites.

The reutilization non-metallic components from a waste-printed circuit board (WPCB) has become one of the most significant bottlenecks in the comprehensive reuse of electronic wastes due to its low value and complex compositions, and it has received great attention from scientific and industrial researchers. To effectively address the environmental pollution caused by inappropriate recycling methods, such as incineration and landfill, extensive efforts have been dedicated to achieving the high value-added reutilization of WPCB non-metals in sustainable polymer composites. In this review, recent progress in developing sustainable polymer composites based on WPCB non-metallic components was systematically summarized. It has been demonstrated that the WPCB non-metals can serve as a promising reinforcing and functional fillers to significantly ameliorate some of the physical and chemical properties of polymer composites, such as excellent mechanical properties, enhanced thermal stability, and flame retardancy. The recovery strategies and composition of WPCB non-metals were also briefly discussed. Finally, the future potentials and remaining challenges regarding the reutilization of WPCB non-metallic components are outlined. This work provides readers with a comprehensive understanding of the preparation, structure, and properties of the polymer composites based on WPCB non-metals, providing significant insights regarding the high value-added reutilization of WPCB non-metals of electronic wastes.

Ultra-strong, ultra-tough, and transparent polymer composite with excellent dynamic and biodegradable properties enabled by bicontinuous structure

Developing plastics that can integrate mechanical (strength and toughness) and dynamic properties (recyclability, repairability, and biodegradability) is commonly challenging. In this work, inspired by the reinforced concrete structure, an ultra-strong and ultra-tough sustainable polymer composite was constructed through uniformly dispersing cellulose nanofiber in a poly(vinyl alcohol) matrix to form a bicontinuous interwoven network structure based on strong yet dynamic hydrogen bonding crosslink sites. The obtained composite showed an ultra-high toughness, a high tensile fracture strength, good Young's modulus and transparency, as well as excellent dynamic properties including good healing ability, recyclability, and biodegradability. Besides, with excellent gas barrier ability and good water vapor permeability, the composite showed great promise to replace traditional polymers for food packaging and preservation. At last, the mechanism behind the good performances is expected to inspire the design of other healable and green polymers in the future.

Sustainable composites for lightweight and flame retardant parts for electric vehicles to boost climate benefits: A perspective

The global automotive sector is moving towards zero-emission transportation, which has led to the rapid growth of the electric vehicles (EVs) market, projected to reach USD 1318 billion in 2028. The two key challenges that EVs are facing are their heavy curb weight (∼ 1000 lbs. heavier than their petroleum-based counterparts) due to their battery packs, and their fire threat, caused by thermal runaway of batteries. Further, growing concerns about the sustainability of EV technology has created pressure on automotive manufacturers to drive innovation of new materials with less environmental impacts. These challenges can be addressed by developing high-performance sustainable polymer composites for lightweight components for EVs with enhanced flame retardancy without compromising their performance. Manufacturing and integration of automotive parts from sustainable composites target and support the “Circular Economy” of EVs. Lightweighting EV components will increase travel ranges, minimize crash impacts, lower braking distances, and reduce the wear and tear of the tires. In sustainable and renewable composite manufacturing, “engineering plastics” including recycled carbon fibers and sustainable resource derived advanced biocarbon will have an edge over “traditional plastics”. In addition, the inclusion of sustainable flame-retardants in the EV components will increase the flashover duration, resulting in better thermal management and delay in thermal runaway. Thus, in this perspective, the recent acceleration in automotive weight reduction strategies is discussed through the utilization of high-performance lightweight and sustainable composites with superior flame retardancy to address the criteria for the circularity of materials towards climate benefits.

Selection of straw waste reinforced sustainable polymer composite using a multi-criteria decision-making approach

AbstractThe valorization of straw waste as a sustainable and eco-friendly resource in polymer composites is critical for resource recycling and environmental preservation. Therefore, many research works are being carried out regarding the development of wheat straw-based polymer composites to identify the reinforcing potential of these sustainable resources. In this study, three different sizes of wheat straw fibers (60–120 mesh, 35–60 mesh, and 18–35 mesh) were used, and their different ratios (0, 2.5, 5, 10, and 20% by weight) were systematically investigated for the physical and mechanical properties of polypropylene-based sustainable composites. The results indicated that the evaluated composites’ properties are strongly dependent on the quantity and size of the utilized wheat straw. Therefore, a preference selection index was applied to rank the developed sustainable polymer composites to select the best composition. Various properties of the composite materials were considered as criteria for ranking the alternatives, namely tensile strength and modulus, flexural stress at conventional deflection and flexural modulus, impact strength, density, water absorption, material cost, and carbon footprint. The decision-making analysis suggests the alternative with wheat straw content of 20 wt.% (35–60 mesh size) dominating the performance by maximizing the beneficial criteria and minimizing the non-beneficial criteria, making it the most suitable alternative. This study will significantly help formulation designers to deal with the amount and size issues when developing polymeric composites.

Sustainable Polymer Composites Manufacturing through 3D Printing Technologies by Using Recycled Polymer and Filler.

In the last years, the excessive use of plastic and other synthetic materials, that are generally difficult to dispose of, has caused growing ecological worries. These are contributing to redirecting the world’s attention to sustainable materials and a circular economy (CE) approach using recycling routes. In this work, bio-filaments for the Fused Filament Fabrication (FFF) 3D printing technique were produced from recycled polylactic acid (PLA) and artisanal ceramic waste by an extrusion process and fully characterized from a physical, thermal, and mechanical point of view. The data showed different morphological, thermal, rheological, and mechanical properties of the two produced filaments. Furthermore, the 3D objects produced from the 100% recycled PLA filament showed lower mechanical performance. However, the results have demonstrated that all the produced filaments can be used in a low-cost FFF commercial printer that has been modified with simple hand-made operations in order to produce 3D-printed models. The main objective of this work is to propose an example of easy and low-cost application of 3D printing that involves operations such as the reprocessing and the recyclability of materials, that are also not perfectly mechanically performing but can still provide environmental and economic benefits.

Silk Fibroin Nanocomposites with Indium Tin Oxide toward Sustainable Capacitive Touch Sensing Applications

The development of multifunctional sustainable polymer composites is an increasing need in the scope of the Internet of Things (IOT) and the circular economy paradigm. In this context, nanocomposites based on silk fibroin (SF) and indium tin oxide (ITO) (up to 40 wt %) were produced by solvent casting to improve the mechanical and dielectric properties of the protein, and develop capacitive touch sensing devices. Samples with good filler dispersion, compact morphology, and optical transparency were obtained independently of the filler content. The structural conformation of ITO/SF nanocomposites and mechanical and dielectric properties are dependent on ITO content, with the dielectric constant reaching values of up to 10 for an ITO content of 40 wt %. On the other hand, the thermal transitions of samples are independent of the filler amount. ITO/SF nanocomposites with 10 wt % ITO content were used for capacitive touch sensor development. The excellent sensing behavior and reproducibility of the device demonstrate the suitability of the developed silk fibroin-based nanocomposites for sustainable electronic approaches.

Improved Extraction of Natural Fibers for Sustainable Polymer Composites

Improved Extraction of Natural Fibers for Sustainable Polymer Composites

Isolation of high crystalline nanocellulose from Mimosa pudica plant fibres with potential in packaging applications

AbstractMimosa pudica Linn (sensitive plant) is a medicinal plant of family Fabaceae. Its stem is a good source of cellulose. This research work reports isolation of cellulose nanocrystals (CNCs) from M. pudica stem fibres by combined chemical and mechanical treatments. Polyvinyl alcohol (PVA)/starch composites were prepared with incorporation of isolated CNC (1, 3 and 5 wt.%) by solution casting method. Addition of CNC in polymer composites improved its mechanical strength and barrier properties. Isolation process of CNC includes alkali treatment, bleaching and acid hydrolysis followed by homogenization. Chemical composition, thermal stability, structure, surface morphology, crystallinity and size of the freeze‐dried nanocellulose were studied carefully. Fourier transform infrared analysis of raw fibre and CNC showed elimination of non‐cellulosic fragments from untreated M. pudica stem fibre. Electron microscopy analysis and dynamic light scattering (DLS) confirmed the isolation of nanocellulose. X‐ray diffraction showed improvement in the crystallinity of obtained nanocellulose. Increase in crystallinity indicates high Young's modulus of isolated nanocellulose which makes them proper reinforcement material in composites. Polymer composites with the addition of 3 wt.% of CNC showed the highest tensile strength and lowest water vapour transmission rate (WVTR), moisture absorption and oxygen transmission rate (OTR). As M. pudica is an abundant natural resource, it can be utilized as an efficient source of nanocellulose for different applications especially as fillers in sustainable polymer composites for packaging.

Curing, thermal and mechanical properties of waste tyre derived reclaimed rubber–wood flour composites

The usage of polymer composites has increased dramatically with the years, especially composites with recycled waste materials since they aid in reducing the environmental pollution. The current study focuses on the use of both waste reclaimed rubber (RR) and wood flour (WF) to make sustainable polymer composites. The curing, thermal, mechanical and morphological properties of the composites were studied. Results showed that the cure rate index and elastic torque of the samples increased with the amount of WF. The mechanical properties of RR–WF composites decreased with increasing wood flour content and tensile strength dropped from 3.33 MPa to 1.35 MPa due to poor interfacial adhesion between WF and RR matrix. The glass transition temperature of styrene–butadiene rubber fraction in composites shifted from ∼15 °C to 10 °C with the addition of WF showing incompatibility between the two phases. The scanning electron microscopy results confirmed incompatibility behavior within the composites as shown by pull-out characteristics of WF from the RR matrix at high content. The results showed that the composite with 10 phr of WF has superior thermal stability, water absorption, and mechanical properties compared to other composites.

Synthesis of polymer composite materials and their biomedical applications

Composites are the macroscopic scale materials formed due to the combination of two or more materials having different compositions, morphology, physical and chemical properties. These materials develop some new or improved physical, chemical, mechanical and other properties which do not convoy to their individual components. These composite materials are developed and synthesized in order to fulfill some special applications. These materials are composed of different polymers and are more common and popularly widespread than the metals and ceramic matrix composites because of their advantages like low cost, ease of processing technology, and variety of applications in different fields especially the advanced medical sectors. In this review we have to focus on the classifications of different polymer composites, their method of synthesis, properties and applications in the biomedical fields. Different reinforcing or filler materials are the major backbone of a composite and their properties trigger the overall properties of the composite. Many polymer composite and green composite materials are bioactive in nature, and due to this particular nature many of these are recently commercialized and some of them are under investigation for the purpose of biomedical applications like bone, artificial skin, heart valve, tendon repair, ligament repair, teeth, oral tissues, and wound dressing. In the advanced medical research many artificial organs of human body can be made from the sustainable polymer composite and biocomposite materials. The advantages of polymeric materials based composite over the other traditional materials and its application in biomedical field are the major concern in this review.

Thermal and structural characterization of acrylonitrile butadiene styrene (ABS) copolymer blended with polytetrafluoroethylene (PTFE) particulate composite

A novel thermally sustainable polymer composite was fabricated with Acrylonitrile Butadiene Styrene (ABS) as the matrix and Polytetrafluroethylene (PTFE) particle as the filler, using injection molding process with 10 and 20 wt% PTFE filler. The composites were characterized by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD) and Thermogravimetric analysis (TGA). The composites were also tested for their visco-elastic properties using Dynamic mechanical analyzer (DMA). The ABS/PTFE composites exhibited high thermal stability and better visco-elastic properties than the ABS matrix. Consequently, this hybrid blended polymer can be a suitable alternative material for tribological applications in both automobile and aerospace industries, among others.

IMPROVING PERFORMANCE AND APPLICABILITY OF GREEN COMPOSITE MATERIALS BY HYBRIDIZATION

A growing concern over environmental issues and the common interest to find a viable alternative to the use of glass or carbon composite reinforcements has led to an increased attention in ecologically sustainable polymer composites. These „green” materials are made by natural fibers, as reinforcement, filled with natural-organic fillers, i.e. derived from renewable or biodegradable sources. At the same time, this relatively new class of materials faces several limits in comparison to traditional composites especially regarding the properties of resistance. This paper investigates the advantages of use of combination of natural fibers for improving mechanical proprieties of „green” composite materials. At the moment, the prevailing opinion is that green composites are not usable in structural applications, and, as a consequence, have to be relegated to unworthy applications (as fillers). On the contrary, there are several evidences that mixing different natural fibers (in practice usually called „hybridization”) leads to an improvement of these material properties. Although usually quite limited in terms of percentage, these improvements from time to time allow a new enlargement in the fields of applications for green composites. Following a large state-of-the-art on green composites, including potential benefits and limits of these materials, the paper proposes several examples of hybridization showing its effect on mechanical proprieties.

IMPROVING PERFORMANCE AND APPLICABILITY OF GREEN COMPOSITE MATERIALS BY HYBRIDIZATION

A growing concern over environmental issues and the common interest to find a viable alternative to the use of glass or carbon composite reinforcements has led to an increased attention in ecologically sustainable polymer composites. These „green” materials are made by natural fibers, as reinforcement, filled with natural-organic fillers, i.e. derived from renewable or biodegradable sources. At the same time, this relatively new class of materials faces several limits in comparison to traditional composites especially regarding the properties of resistance. This paper investigates the advantages of use of combination of natural fibers for improving mechanical proprieties of „green” composite materials. At the moment, the prevailing opinion is that green composites are not usable in structural applications, and, as a consequence, have to be relegated to unworthy applications (as fillers). On the contrary, there are several evidences that mixing different natural fibers (in practice usually called „hybridization”) leads to an improvement of these material properties. Although usually quite limited in terms of percentage, these improvements from time to time allow a new enlargement in the fields of applications for green composites. Following a large state-of-the-art on green composites, including potential benefits and limits of these materials, the paper proposes several examples of hybridization showing its effect on mechanical proprieties.

Spectroscopic chemical insights leading to the design of versatile sustainable composites for enhanced marine application

A versatile strategy for the design of sustainable polymer composites, based on photo-cured linseed oil resin, offers attractive prospects for the marine industry.

Synthesis and Characterization of AN-g-SOY for Sustainable Polymer Composites

Biobased materials are rapidly emerging as alternatives to petroleum-based materials because of rising environmental awareness and augmented consumption of nondegradable polymers. In the present work, the surface characteristics of biorenewable soy flour (SOY) were tailored via free radical-induced graft copolymerization of acrylonitrile (AN) to develop novel materials for multifunctional applications. A number of reaction parameters were optimized to maximize the level of grafting. The synthesized acrylonitrile-grafted soy (AN-g-SOY) copolymers were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Polymer composites were prepared using SOY/AN-g-SOY as reinforcement and poly(methyl methacrylate) (PMMA) as the matrix. Dynamic mechanical analysis results showed that acrylonitrile-grafted SOY exhibited significantly enhanced storage modulus compared to polymer composites reinforced with pristine soy flour.

A Sustainable Polymer Composite from Recycled Polypropylene Filled with Shrimp Shell Waste

This research explores the potential of using recycled polypropylene (PP) incorporated with shrimp shell waste to produce a sustainable polymer composite. In this study, the mechanical and physical properties of recycled polypropylene/shrimp shell (rPP/SS) composites prepared by melt compounding and compression molding techniques were evaluated. The effects of SS loading were investigated by using various compositions of rPP/SS composites, ranging from 0 to 8 wt.% SS that consists of two different sizes, i.e., fine and coarse SS. The composites were tested for their mechanical and physical properties using impact, tensile and water absorption tests. Furthermore, the morphology of the composites was examined by using a scanning electron microscope (SEM). Incorporation of SS was found to increase the Young's modulus of the rPP, but the impact and tensile strength showed a decrease. However, we observed that both the impact and tensile strength improve with the further increase of the SS content. In other words, composites with high shrimp shell loading were observed to exhibit better tensile and impact properties compared to composites with low shrimp shell loading. Moreover, at 8 wt.% of SS, the value of tensile strength is comparable to that of neat rPP.