Starch-based biodegradable materials: Challenges and opportunities

Recent advances in the development of biodegradable PHB-based toughening materials: Approaches, advantages and applications

Natural fibre-reinforced polymer composites (NFRPCs) are emerging as sustainable, lightweight materials with significant potential for aerofoil applications in the aerospace industry. This review explores the mechanical properties of NFRPCs that incorporate natural fibres, resin matrices, and fillers, focusing on their tensile strength, flexural performance, impact resistance, and fatigue durability. Natural fibres, such as flax, jute, hemp, and Doum palm leaf, are evaluated for their structural benefits, while epoxy resin is highlighted as a preferred matrix due to its high adhesion and thermal stability. Fillers, including silica, calcium carbonate, and nano-clay, are discussed for their role in enhancing the composite’s strength, thermal properties, and impact resistance, making NFRPCs suitable for demanding aerofoil applications. Adding fillers further improves performance, particularly in terms of durability, stiffness, and environmental resistance, which are crucial for aerofoil structures. The review also examines variability in natural fibre properties and presents strategies to address these issues through fibre treatments and hybridization techniques. Less research has focused on combining multiple natural fibres with fillers to create hybrid composites, which have shown promising mechanical enhancements in existing studies. Future directions are suggested to optimize NFRPCs for aerospace applications by using epoxy resin for improving fibre-matrix bonding. The review underscores the potential of NFRPCs as a sustainable and high-performance material solution for lightweight aerofoil structures in aerospace. Further investigation into innovative filler-natural fibre combinations, such as Calcium Sulphate Hemihydrate (CaSO₄·½H₂O) and Doum leaf stalk composites, could unlock new opportunities in aerospace and engineering fields.

This research study compares the effect of polypropylene and wool fibers on the mechanical properties of natural polymer based stabilized soils. Biocomposites are becoming increasingly prevalent and this growth is expected to continue within a number of sectors including building materials. The aim of this study was to investigate the influence of different fiber reinforced natural polymer stabilized soils with regards to mechanical properties and fiber adhesion characteristics. The polymer includes alginate, which is used in a wide range of applications but has not been commonly used within engineering and construction applications. In recent years, natural fibers have started to be used as an ecological friendly alternative for soil reinforcement within a variety of construction applications. Test results in this study have compared the effects of adding natural and synthetic fibers to clay soils and discussed the importance of an optimum soil specification. A correlation between the micro structural analysis using scanning electron microscope (SEM), fiber typology, fiber–matrix bonds and the mechanical properties of the stabilized soils is also discussed.

Natural fiber-reinforced polymer composites are presently receiving the attention of scholars and industrialists due to their specific properties, such as being naturally eco-friendly, biodegradable, economical, viable, available, and sustainable. The key problems associated with natural fiber polymer composites, including fiber/matrix compatibility, high moisture absorption, and, especially, thermal degradation in engineering plastics (high-temperature plastics), constitute the most critical thrust of this review. It is noted that at high temperatures, natural fibers degrade and this has adversely restricted their usage with only commodity thermoplastics having relatively low melting temperatures, such as polypropylene (PP) and polyethylene (PE). This review paper, therefore, provides valuable research highlights on utilizing and improving the mechanical and thermal properties of natural kenaf fibers as reinforcement in engineering polymer composites for high-temperature engineering applications using polymer matrices, such as polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), and polyphenylene ether (PPE). The initial and various chemical treatments of natural fibers, their effect on the thermal and performance properties of natural fiber engineering thermoplastic composites, and the advanced treatment of epoxy coatings are reviewed. Applications of natural fiber-reinforced thermoplastic composites in the construction and automotive industries, as well as in other applications, are outlined. It was established that the adhesion and thermal stabilities between polymer matrix and natural fibers are better improved by surface coating with diluted epoxy resin thermoset. This eventually improved the overall thermal and performance properties of the resultant composites and will serve as a data bank and guide for manufacturers and future research directions using high-end engineering polymers with higher processing temperatures.

Abstract

In this work, two different natural fillers (alfa fibers and clay particles) were used to produce hybrid composites based on polypropylene. The samples were compounded by twin-screw extrusion and injection molding. As a first step, a constant overall filler loading was used (30 wt%) to study the effect of the relative filler loading. To improve adhesion with a matrix, alfa fibers were surface treated using an alkali solution, while the clay was purified and grinded to reduce particle sizes. The morphological, thermal, and mechanical properties (quasi-static and dynamic properties) were studied and found to vary with filler type and relative content. From the results obtained, it can be concluded that natural fiber-reinforced polymers combined with natural particulate fillers have advantages in terms of mechanical properties improvement, while increasing the use of natural materials. These hybrid composites show that new avenues are possible to reduce the use of synthetic fillers in composites.

The present environmental concern has motivated researchers to develop bio-polymer based wear materials. In the recent review article focus has been made for proper utilization of natural resources for developing advanced wear resistance material. In order to develop polymer based composite materials with natural fibre and filler, various chemical treatments are focused in the review article. Apart from this the paper also concerned variety of bio-resources products for synthesis of new epoxy grade polymer material. The developed material can be well utilized in various fields such as automobile brake pad, griping material, building construction, heavy machinery, surface modification and improvement. The review work focused on various parameters that are associated with wear behaviour. i. A brief discussion about natural fibres, polymers, their applications and basics of tribology. ii. Effect of the natural filler/fibre weight percentage, orientation of fibre, fibre length, chemical treatment, fibre physical and mechanical properties and are studied. iii. Wear parameters such as amount applied load, sliding velocity, sliding distance, loading time duration, dry and wet condition are focused. The proper utilization of the each and every unutilized part of the bio-products are studied. The various section of the plant i.e. steam, leaf, roots, skin etc. proper utilization of each part of the plant based on its application are studied with suitable epoxy polymer material. The work will most beneficial for improving the wear material in line with tribological behaviour, with proper utilization of natural waste products.

7 - Compressive and fracture toughness of natural and synthetic fiber-reinforced polymer

Recent advancements of plant-based natural fiber–reinforced composites and their applications

In recent years, there have been a tremendous increase in interest, research and development in the natural fiber, biopolymers and polymers materials for their use in bio-composite, packaging, agriculture, medicine etc. Many scientists are modifying traditional materials to more user-friendly and novel polymer composites out of naturally occurring materials. Low recycling rates and the high volume of non-degradable plastics have shortened dramatically the life expectancy of current commercial landfills and increased the demand of biodegradable plastic packaging materials. A number of biological materials may be incorporated into biodegradable polymer materials like cellulose, starch and fiber extracted from various plants. The aim behind these judicious and planned efforts are to procure andpromote the biodegradable polymer materials that would reduce the need for the synthetic polymer production while reducing the pollution at a lower cost . This paper provides an insight to the progress in process in the field of the utilization of natural fiber and biodegradable polymer.

The need for alternative eco-friendly and sustainable materials has forced many researchers to focus on composites made using natural fibers and biodegradable polymer matrices. In addition to that, these natural fibers are low in cost, have good mechanical properties, biodegradability, and require less production energy. Therefore, this review paper will focus on one of the natural fibers known as Luffa cylindrica (LC) by understanding all the natural fibers' benefits. A detailed overview is provided for commonly used fiber surface treatments, surface treatment techniques, and processing techniques for various LC composites from numerous other researches. Furthermore, this paper will also discuss the characteristics, mechanical properties, and water absorption properties of LC composites before and after surface treatments, where a comprehensive understanding of LC reinforced polymer composites' behavior has been reviewed.

Polymer blends and composites from renewable resources

The natural fiber-reinforced polymer composites are recognized as an alternative to wood and plastics in recent years. The natural plant fibers are extracted from various parts of the tree and are used in polymer composites. Natural fibers have gained popularity over synthetic fibers because of their low cost, lightweight, abundance as natural and renewable resources, and versatile mechanical properties, among others. Natural fibers in numerous applications in many fields such as automotive, textile, fiberboard, cushion, paper, mattress, door, wall panel, air cleaner, dashboard and insulation mat manufacturing, as well as in the construction and transportation industries. This present investigation focuses on boiled eggshell particulated banana fiber-polyester composites. The resin content of 60% is maintained constantly, and reinforcement is maintained as fiber content of 40-x%, where x is the particulate content in weight % was maintained for the different combination of fabrication parameters. The tensile strength of fabricated composites has been evaluated as per ASTM standards. The effect of fiber length and filler content on the mechanical behaviors of banana fiber-polyester composites was studied using ANOVA and surface plots. The nonlinear regression models have developed for the prediction of mechanical behaviors over the specified range of conditions and optimized the better values of parameter.

In developing natural fiber composites (biocomposites), compatibility between natural cellulosic fibers and polymers has always created serious challenges, reducing performance. This study focused on applying a novel approach using epoxy resin as a coating medium to enhance the properties of the fibers and the interface between the hydrophobic polymer and the hydrophilic natural fiber. 10 wt% of uncoated kenaf fibers (KF) and coated kenaf (CKF) fibers were compounded with acrylonitrile butadiene styrene (ABS) thermoplastic polymer in a twin-screw extruder at an optimized temperature of 220°C under the same processing conditions. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) examined the coated and uncoated fibers' physicochemical compositions and surface properties. The developed composites' thermal, mechanical, and microstructural characteristics were also examined, and the results revealed that the CKF/ABS composites had better interfacial bonding and mechanical characteristics than the uncoated KF/ABS composite. Coating natural fibers with epoxy resin is a novel technique for improving interfaces and developing environmentally friendly composites from natural sources.

The plastic products contribute to environmental pollution. Replacing the plastic materials with biodegradable materials with superior properties is an absolute necessity and important research direction for the near future. The first steps in this regard were the creation of composite materials containing natural fibers with positive effects on the environment that have penetrated in different fields. The bioplastics and biocomposites made from natural fibers is a topical solution. The next step was made towards obtaining biodegradable and recyclable materials based on cellulose, lignin and no carcinogens. In this category fall the “liquid wood” with a use up to five times without affecting the mechanical properties. “Liquid wood” is a high quality thermoplastic biocomposite. “Liquid wood” is a biopolymer composite divided in three categories, ARBOFORM®, ARBOBLEND® and ARBOFILL®, which have differed composition in terms of lignin percentage, being delivered by Tecnaro, as granules, [1]. The paper’s research was focus on Arboform L V3 Nature and Arboform L V3 Nature reinforced with aramid fiber. In the experimental plan were taken into account six parameters (Dinj - direction of injection [°]; Ttop - melting temperature [°C]; Pinj - injection pressure [MPa] Ss - speed [m/min]; tinj – injection time [s] and tc - cooling time [s]) each with two levels, research carried on by Taguchi methodology. Processing Taguchi method allowed both Taguchi setting work parameters influence on storage modulus and damping as the size and influence their ranking. Experimental research concerning the influence technological parameters on storage modulus of samples obtained by injection from Arboform L V3 Nature yielded an average of 6055MPa and descending order as follows: Trac, Ss, Pinj, Dinj and Ttop. The average of model for reinforced material was 6419MPa and descending order of parameters influence such as: Dinj, Trac, Ttop, tinj, Ss and Pinj.