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Biodegradable polymers have become important in different fields of application, where biodegradability and biocompatibility are required. Herein, the melt spinning of biodegradable polymers including poly(lactic acid), poly(butylene succinate), polyhydroxyalkanoate (PHA), poly(ɛ-caprolactone) and their biocomposites is critically reviewed. Biodegradable polymer fibers with added functionalities are in high demand for various applications, including biomedical, textiles, and others. Melt spinning is a suitable technique for the development of biodegradable polymer fibers in a large-scale quantity, and fibers with a high surface area can be obtained with this technique. The processing variables during spinning have a considerable impact on the resulting properties of the fibers. Therefore, in this review, the processing-property relationship in biodegradable polymers, blends, and their composites is provided. The morphological characteristics, load-bearing properties, and the potential application of melt-spun biodegradable fibers in various sectors are also provided.

The current society is experiencing serious problems in terms of energy and environmental pollution. Environmentally friendly and renewable sources such as phase change materials have been employed as a reliable and effective source of energy storage. Phase change materials (PCMs) are known to absorb or release sizeable amount of energy during melting and solidification process. PCMs have been employed in both thermal protection and energy storage systems, more in active as well as passive cooling applications. However, PCMs are associated with low thermal conductivity, which hinders the process of heat rate exchange during the melting/solidification cycles. To improve the thermal conductivity of PCMs, various conductive fillers have been incorporated to such systems. Thermal cycle test is done to verify the stability of PCMs in thermal energy storage systems. This review emphasizes on the morphology, preparation methods and thermal cycle of various types of PCMs in the presence of conductive filler. Furthermore, the bibliometric analysis based on key research areas, top ten leading countries, and citations by country on phase change materials for energy storage research are reported in this review paper. The bibliometric analysis shows the dominance of the People’s Republic of China on PCMs for energy storage research.

Wood-plastic composites (WPCs) are a group of emerging and a sustainable class of high-performance materials, consisting of polymers reinforced with wood particulates, having a wide range of applications in the field of building, infrastructure, and transportation. However, the main drawback of the WPCs is their high flammability. Fire retardants usually enhance WPCs’ flame retardancy but at the expense of mechanical properties. This paper reviews the available literature on flame retardant WPCs in developing an optimum condition between the flammability and mechanical properties, i.e., the addition of wood-flour and flame retardant (FR) in order to find a balance between the flammability resistance and their mechanical properties. It concentrates on the recent advances in the mechanical properties and flammability studies of wood flour-polymer composite products. The applications and durability of these flame retardant WPCs with future remarks are also highlighted.

In the past, polymer materials have been used in electronic devices; however, the major drawback with polymers is their low thermal conductivity, i.e., 0.1–0.5 W/(m・K). Hence, researchers came up with the idea of incorporating conductive fillers into the polymer matrix in order to increase their thermal conductivity. Different conductive materials classified as carbon, metallic, and ceramic-based fillers have been used for this task. However, the drawback with carbon and metalbased fillers is that they reduce the intrinsic insulating properties of polymer materials. Recently, boron nitride (BN), a ceramic-based filler was selected as the conductive filler of choice due to its combined excellent thermal conductivity and electrical insulation as well as high breakdown strength. Due to differences in polarities, boron nitride and polymer matrices form a weak interfacial bond. Therefore, the weak interfacial bond is commonly improved by surface chemical modification of the boron nitride fillers. Furthermore, most of the theoretical models are used to predict the thermal conductivities of boron nitride-polymers composites fitted well with experimental data. This proved that the models could be used to predict the properties of boron nitride composites before their experimental data. The review paper discusses the effect of boron nitride orientation, nanostructures, modification, and its synergy with other conductive fillers on the thermal conductivity and mechanical properties of the polymer matrices.

Copyright: 2020 Wiley. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website: https://doi.org/10.1002/pc.25590

This paper deals with the development of cellulose nanofibres (CNFs) reinforced biopolymers for use in packaging applications. Cellulose nanofibres were extracted from sawdust by a combination of chemical and mechanical treatments. The extracted cellulose nanofibres were chemically modified (fCNFs) and characterised by Fourier Transform Infrared Spectroscopy (FTIR). Bionanocomposites were prepared from biopolymers polylactic acid/polybutylene succinate (PLA/PBS) and cellulose nanofibres by compounding in a twin-screw extruder followed by injection moulding. The developed bionanocomposites were subjected to mechanical and thermal characterisation. As part of product development, CNF-biopolymer pellets were also extruded into filaments which were then 3D printed into prototypes. This work is a successful demonstration of conversion of waste residues into value-added products, which is aligned to the principles of circular economy and sustainable development.

This review describes the recent advances in the production and application of cellulose nanomaterials. Cellulose nanomaterials (CNMs), especially cellulose nanocrystals and cellulose nanofibers, can be produced using different preparation processes resulting in materials with unique structures and physicochemical properties that are exploited in different fields such as, biomedical, sensors, in wastewater treatment, paper and board/packaging industry. These materials possess attractive properties such as large surface area, high tensile strength and stiffness, surface tailor-ability via hydroxyl groups and are renewable. This has been a driving force to produce these materials in industrial scale with several companies producing CNMs at tons-per-day scale. The recent developments in their production rate and their applications in various fields such as medical sector, environmental protection, energy harvesting/storage are comprehensively discussed in this review. We emphasize on the current trends and future remarks based on the production and applications of cellulose nanomaterials.

The continuous growth of greenhouse gas emission and rising costs of fossil fuels are the major driving force behind high rate of research on effective utilization of energy. The storage of energy through different innovative capacitors and otherwise are some of the trending research. In this review, more about polyolefin/wax blend composites are discussed and explored as a potential system of energy. Phase changes and effect of each component in polyolefin/wax blend composites and eventual energy storage are discussed. Latent heat storage system through phase change materials (PCMs) remained effective way of storing thermal energy. This promoted some applications including solar energy utilization, waste heat recovery and air-conditioned building. There are disadvantages such as poor heat conductors, in which heat transport amongst the components of the phase change material is relatively slow in polyolefin/wax blend composites. In most cases, based on the chemical constituents of the polyolefins and phase change materials, shape-stabilized PCM materials are naturally flammable which limits their applications. This review summarizes the thermal conductivity, mechanical, flammability and thermal properties based on polyolefins/PCMs blends and their composites and highlights possible recommendations.

Sugar cane bagasse (SB) fibres were mechanically treated with a supermass colloider and blended in poly(ethylene oxide) matrix by solution mixing. Dimensions of the fibres diminished directly proportional to the mechanical passes. The fibres were well dispersed in the PEO matrix, with only few fibre pull-outs, especially for the highest mechanical passes. SEM, FTIR, XRD and DSC showed strong interfacial interaction and fluctuation in crystallinity with mechanical passes. The increase in mechanical treatment improved mechanical properties in line with the passes within experimental uncertainty. The presence of SB in PEO increased thermal stability which improved with the mechanical passes, except the interesting sudden drop at the highest passes.

Copyright: 2019 Wiley. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, kindly consult the publisher's website.

Natural fibers, as replacement of engineered fibers, have been one of the most researched topics over the past years. This is due to their inherent properties, such as biodegradability, renewability and their abundant availability when compared to synthetic fibers. Synthetic fibers derived from finite resources (fossil fuels) and are thus, affected mainly by volatility oil prices and their accumulation in the environment and/or landfill sites as main drawbacks their mechanical properties and thermal properties surpass that of natural fibers. A combination of these fibers/fillers, as reinforcement of various polymeric materials, offers new opportunities to produce multifunctional materials and structures for advanced applications. This article intends to cover recent developments from 2013-up to date on hybrid composites, based on natural fibers with other fillers. Hybrid composites preparation and characterization towards their applicability in advanced applications and the current challenges are also presented.

Three-dimensional (3D) printing, also known as additive manufacturing (AM), has garnered much interest from academia and industry for rapid prototyping and manufacturing. This chapter provides a brief history about 3D printing, reviews the most used 3D printing techniques for biopolymers and their nanocomposites, and presents the current applications. Future trends and challenges of this technology are also addressed. The innovative ideas associated with techniques and printing materials to overcome these challenges are also presented.

The utilization of layered nanofillers in polymer matrix, as reinforcement, has attracted great interest in the 21st century. This can be attributed to the high aspect ratios of the nanofillers and the attendant substantial improvement in different properties (i.e., increased flammability resistance, improved modulus and impact strength, as well as improved barrier properties) of the resultant nanocomposite when compared to the neat polymer matrix. Amongst the well-known layered nanofillers, layered inorganic materials, in the form of LDHs, have been given the most attention. LDH nanofillers have been employed in different polymers due to their flexibility in chemical composition as well as an adjustable charge density, which permits numerous interactions with the host polymer matrices. One of the most important features of LDHs is their ability to act as flame-retardant materials because of their endothermic decomposition. This review paper gives detailed information on the: preparation methods, morphology, flammability, and barrier properties as well as thermal stability of LDH/polymer nanocomposites.

Nanoparticles are generally defined as particles having one or more dimensions of sizes ranging from 1 to 100 nm. Nanoparticles can be classified into organic, inorganic and carbon-based materials. In comparison with conventional micro-size particles, nanoparticles show enhanced properties, such as high reactivity, strength, surface area, sensitivity and stability due to their nanosize. Various preparation methods, viz. physical, chemical and mechanical, have been employed to synthesize different nanoparticles. This chapter presents an overview on nanoparticles and their types, properties, synthesis methods and application in bioconversion of biomass into biofuels.

Human well-being and safety are of the utmost importance for both the physical and mental well-being of every human. Besides the huge advances in antibacterial drugs, many infectious diseases are still difficult to cure or even control. Infectious diseases are a consequence of pathogenic microbes and they kill many people. An antibiotic agent is a substance that can be active against bacteria for the inhibition of bacterial infections. Besides, even with the considerable number of antibiotic agents developed in the past, up to this point, countless infectious diseases are still difficult to cure. Antibiotic/antimicrobial activity of polymers and/or composites have demonstrated superior efficacy, less toxicity, less environmental problems, and considerable resistance. Different metals have been found to be good antibiotic agents for bacteria at low content. The objective of this chapter is to report on the different polymer/metal nanocomposite systems for antibiotic activity, with a special focus on health applications.

Since its introduction in the past 25 years, three-dimensional (3D) printing has been a major research topic owing to its potential to overcome the limitations of conventional 3D manufacturing techniques, that is, to control the overall architecture toward various applications. In the third (2013–present) decade, 3D printing enters a new phase in which researchers fabricate clinical constructs that benefit the current society. In this chapter, we briefly discuss the recent progress of 3D printing and challenges related to the antibiotic materials and manufacturing process for biomedical applications.

Cellulose nanofibril (CNF) paper has various applications due to its unique advantages. Herein, we present the intrinsic mechanical properties of CNF papers, along with the preparation and properties of nanoparticle-reinforced CNF composite papers. The literature on CNF papers reveals a strong correlation between the intrafibrillar network structure and the resulting mechanical properties. This correlation is found to hold for all primary factors affecting mechanical properties, indicating that the performance of CNF materials depends directly on and can be tailored by controlling the intrafibrillar network of the system. The parameters that influence the mechanical properties of CNF papers were critically reviewed. Moreover, the effect on the mechanical properties by adding nanofillers to CNF papers to produce multifunctional composite products was discussed. We concluded this article with future perspectives and possible developments in CNFs and their bionanocomposite papers.

This paper reports on the potential of electrospun alginate nanofibre membranes to be used for the bio-sorption of heavy metals from aqueous solutions. Poly(ethylene oxide) (PEO) and its blends were electrospun at an applied voltage of 1–1.3 kV/cm and a solution flow rate of 0.8 mL·hr–1. The electrospinnability of the nanofibre blends was enhanced by storing the blend solutions in a controlled environmental chamber. The electrospun nanofibre membranes were washed with calcium chloride to remove PEO. Beadless nanofibres with average diameters of 114 nm and a surface area of 18.03 m2·g–1 were obtained. Fourier transform infra-red (FTIR) spectroscopy and thermogravimetric analysis (TGA) confirmed the removal of PEO after washing with calcium chloride. The adsorption behaviour of the nanofibrous membranes was investigated using Cu(II) as model metalloid at different concentrations (0–1000 mg·L–1), temperatures (25, 40, and 60 °C) and pH values (2–6). The Langmuir isotherm better presented the equilibrium experimental data than the Freundlich model. The electrospun alginate membranes displayed a maximum monolayer sorption capacity (Q0) of 15.6 mg·g–1 at a pH of 4. In a competitive adsoption experiment the removal of metal ions in a mixture followed the order Cu > Ni > Cd > Co.

This chapter discusses different types of composites, processing and their biodegradation studies. Polymer composites have been used in various applications, such as automotive, aerospace, construction and packaging; and their market is growing immensely. The composite reinforced with alkali-treated hemp fabrics displayed lower tensile strength and modulus as well as lower flexural strength and modulus in comparison with composites reinforced with untreated hemp fabrics. Synthetic polymers reinforced with natural fibres have been extensively used in packaging and automotive applications. Composite is an emerging area, and it offers an opportunity to replace synthetic products made from petroleum-based resources. The reason for slower degradation of biocomposites could be due to the addition of crystalline cellulose nanofibres which delays biodegradation. The crystallinity of biocomposites increased with an increase in exposure time, which could be due to the degradation in the amorphous regions by microorganisms.

Polycaprolactone (PCL) is one of the most used synthetic polymers for medical applications due to its biocompatibility and slow biodegradation character. Combining the inherent properties of the PCL matrix with the characteristic of nanofibrous particles, result into promising materials that can be suitable for different applications, including the biomedical applications. The advantages of nanofibrous structures include large surface area, a small diameter of pores and a high porosity, which make them of great interest in different applications. Electrospinning, as technique, has been heavily used for the preparation of nano- and micro-sized fibers. This review discusses the different methods for the electrospinning of PCL and its composites for advanced applications. Furthermore, the steady state conditions as well as the effect of the electrospinning parameters on the resultant morphology of the electrospun fiber are also reported.

In recent years, nanomaterials played a key role in developing novel polymer nanocomposites with multifunctional properties. Nanomaterials that will be reviewed in this study are nanoclays, carbonaceous (carbon nanotubes and graphene) and nanocellulose. This chapter reviews the effects of nanomaterials and nanomaterials hybrid on mechanical, thermal, rheological and dynamic mechanical properties of polymer nanocomposites. In the last decades, biobased and biodegradable polymers (biopolymers) reinforced with nanomaterials have been a research hotspot. However, this chapter also reviews the recent developments of polymer nanocomposites from biopolymers and nanomaterials.

PLA is one of the promising biopolymer featuring unique properties such as excellent biodegradability, biocompatibility, good mechanical strength and easy processability. Although its properties are comparable to synthetic polymers, its success is impeded by its cost and brittleness. In order to further extend its applicability in different fields, blending with other cheaper and ductile/flexible polymers has been subjecting of the research since its introduction early in the 1880s. It is recognized that direct blending usually results in unanticipated properties because of PLA immiscibility with other polymers. In this chapter, we discuss the challenges faced in direct blending PLA with other polymers and the use of compatibilizers and/or plasticizers to improve the processability and/or performance of the resulting blend. The opportunities and progress made with some strategies to minimize the immiscibility of PLA with other biopolymers are also discussed. We concluded with future trends and recommendations that should enable the production of high-end performance PLA-based bio-blends.

Nanoparticles show high toxicity towards various pathogenic microbes, however, the control over their release and/or release rate has been the major subject in research. Over the past decade’s research has escalated on the use of the polymeric material as the host to hold the nanoparticles in order to control their release rate. Biopolymers, owing to their unique properties such as biodegradability, renewability, and recyclability have been used as host matrices for various nanoparticles. Different processing techniques such as melt compounding and solution casting were employed to fabricate polymer nanocomposites. In this chapter, we reviewed the preparation and characterization of sustainable antimicrobial nanocomposites, the strategies to enhance their antibacterial activity as well as future prospects of these interesting materials. We also highlight the preparation of different antibacterial nanoparticles and recent developments.

The increasing demand for environmental and waste management policies globally has motivated researchers to focus on the development of biocomposites from renewable resources such as lignocellulosic materials and biopolymers in order to protect the environment. The release of polymers as waste materials generated a significant problem to the environment after service life. Authorities globally are encouraging people to employ more green materials from renewable resources. Biodegradable polymers from natural resources provide with an excellent opportunity to reduce the reliance on petroleum-derived polymers such as polyethylene and polypropylene. Among the well-known biodegradable polymers, polylactic acid (PLA) has a huge commercial potential because of its good biocompatibility, aesthetics, and easy processability in different mixing techniques. Polylactic acid is a biodegradable from renewable resources such as starch and corn. Currently, attention has been paid to the use of bio-reinforced composites which are applied in automotive, construction, and packaging applications. This chapter discusses the current research efforts, challenges, different preparation methods, and applications of polylactic acid (PLA)/fiber composites.

Over the past decades, research has escalated on the use of polylactic acid (PLA) as a replacement for petroleum-based polymers. This is due to its valuable properties, such as renewability, biodegradability, biocompatibility and good thermomechanical properties. Despite possessing good mechanical properties comparable to conventional petroleum-based polymers, PLA suffers from some shortcomings such as low thermal resistance, heat distortion temperature and rate of crystallization, thus different fillers have been used to overcome these limitations. In the framework of environmentally friendly processes and products, there has been growing interest on the use of cellulose nanomaterials viz. cellulose nanocrystals (CNC) and nanofibers (CNF) as natural fillers for PLA towards advanced applications other than short-term packaging and biomedical. Cellulosic nanomaterials are renewable in nature, biodegradable, eco-friendly and they possess high strength and stiffness. In the case of eco-friendly processes, various conventional processing techniques, such as melt extrusion, melt-spinning, and compression molding, have been used to produce PLA composites. This review addresses the critical factors in the manufacturing of PLA-cellulosic nanomaterials by using conventional techniques and recent advances needed to promote and improve the dispersion of the cellulosic nanomaterials. Different aspects, including morphology, mechanical behavior and thermal properties, as well as comparisons of CNC- and CNF-reinforced PLA, are also discussed.

The need for utilization of environmentally friendly materials has emerged due to environmental pollution that is caused by non-biodegradable materials. The usage of non-biodegradable plastics has increased in the past decades in many industries, and, as a result, the generation of non-biodegradable plastic wastes has also increased. To solve the problem of non-biodegradable plastic wastes, there is need for fabrication of bio-based polymers to replace petroleum-based polymers and provide strategic plans to reduce the production cost of bioplastics. One of the emerging bioplastics in the market is poly (butylene succinate) (PBS) and it has been the biopolymer of choice due to its biodegradability and environmental friendliness. However, there are some disadvantages associated with PBS such as high cost, low gas barrier properties, and softness. To lower the cost of PBS and enhance its properties, natural lignocellulosic fibers are incorporated into the PBS matrix, to form environmentally friendly composites. Natural fiber-based biocomposites have emerged as materials of interest in important industries such as packaging, automobile, and construction. The bonding between the PBS and natural fibers is weak, which is a major problem for advanced applications of this system. As a result, this review paper discusses various methods that are employed for surface modification of the Fibers The paper provides an in-depth discussion on the preparation, modification, and morphology of the natural fiber-reinforced polybutylene succinate biocomposites. Furthermore, because the preparation as well as the modification of the fiber-reinforced biocomposites have an influence on the mechanical properties of the biocomposites, mechanical properties of the biocomposites are also discussed. The applications of the natural fiber/PBS biocomposites for different systems are also reported.