The objective of this investigation was to characterize the performance of natural fiber reinforced polypropylene composites in fused deposition modelling (FDM). Composite filaments comprising of pre-consumer recycled polypropylene with varying contents of hemp or harakeke fibers were extruded from which tensile test specimens were made using FDM. Filament and test specimens were tensile tested and properties were compared with plain polypropylene samples; the ultimate tensile strength and Young’s modulus of reinforced filament increased by more than 50% and 143%, respectively, for both 30 wt % hemp or harakeke compared to polypropylene filament. However, the same degree of improvement was not seen with the FDM test specimens, with several compositions having properties lower than for unfilled polypropylene. SEM analysis of fracture surfaces revealed uniform fiber dispersion and reasonable fiber alignment, but porosity and fiber pull-out were also observed. Fiber reinforcement was found to give benefit regarding dimensional stability during extrusion and FDM, which is of major importance for its implementation in FDM. Recommendations for optimization of processing in order to enhance build quality and improve mechanical properties are provided.

Characterizing the Mechanical Properties of Fused Deposition Modelling Natural Fiber Recycled Polypropylene Composites

Carbon based nanofillers (graphene and carbone nanotube) are widely used as reinforcing agents with epoxy based nanocomposites. The aim of paper is to review mechanical properties of two phase and three phase composites, fabricated by incorporating graphene and carbon nanotube (CNT) nanofillers in epoxy resin individually followed by studying the synergetic effect of hybrid nanofillers in the epoxy resin. Discussion on verification of results by various characterization techniques such as SEM, TEM, XRD, and FTIR is done to understand the influence of filler materials on interfacial properties of composites along with presenting various diversified applications of epoxy based composites.

Effect of Carbon Nanofillers on the Mechanical and Interfacial Properties of Epoxy Based Nanocomposites: A Review

Parallel to the flourishing of inorganic-organic hybrid perovskite solar cells (PSCs), the development of inorganic cesium-based metal halide PSCs (CsPbX3) is accelerating, with power conversion efficiency (PCE) values of over 20% being obtained. Although CsPbX3 possesses numerous merits, such as superior thermal stability and great potential for use in tandem solar cells, severe challenges remain, such as its phase instability, trap state density, and absorption range limitations, hindering further performance improvements and commercialization. This review summarizes challenges and strategies relating to each device functional layer and their integration for the purposes of performance improvement and commercialization, utilizing the fundamental configuration of a perovskite photo-absorption layer, electron transport layer (ETL), and hole transport layer (HTL ). In detail, we first analyze comprehensively strategies for designing high-quality CsPbX3 perovskite films, including precursor engineering, element doping, and post-treatment, followed by discussing the precise control of the CsPbX3 film fabrication process. Then, we introduce and analyze the carrier dynamics and interfacial modifications of inorganic ETLs, such as TiO2, SnO2, ZnO, and other typical organic ETLs with p-i-n configuration. The pros and cons of inorganic and organic HTLs are then discussed from the viewpoints of stability and band structure. Subsequently, promising candidates, i.e., HTL-free carbon-electrode-based inorganic CsPbX3 PSCs, that meet the "golden triangle" criteria used by the PSC community are reviewed, followed by discussion of other obstacles, such as hysteresis and large-scale fabrication, that lie on the road toward PSC commercialization. Finally, some perspectives relating to solutions to development bottlenecks are proposed, with the attempt to gain insight into CsPbX3 PSCs and inspire future research prospects.

Challenges and strategies relating to device function layers and their integration toward high-performance inorganic perovskite solar cells.

Fused deposition modelling is a simple additive manufacturing technology utilising fine filament extrusion of predominantly thermoplastic materials to build 3D objects layer by layer. This research explores the feasibility and the factors involved in using fused deposition modelling to produce natural fibre reinforced composite components. Uniform 3-mm filaments of both hemp and harakeke (Phormium tenax) in varying weight percentages within polylactic acid (PLA) polymer were successfully produced and used to print tensile test samples. Tensile test results supported harakeke to be a useful fibre in terms of mechanical properties achieved which surpassed the Young’s modulus and tensile strength of plain PLA samples by 42.3% and 5.4%, respectively.

Fused Deposition Modelling of Natural Fibre/Polylactic Acid Composites

Nowadays, there is greater demand for greener materials in societies due to environmental consciousness, depleting fossil fuels and growing ecological concerns Within the foreseeable future, industries and suppliers will be required to be more aware of challenges faced due to the availability of resources and use more sustainable and renewable raw materials In this context, cellulose can be expected to become a vital resource for materials owing to its abundance, versatility as a biopolymer, several different forms and potential applications Thus, all-cellulose composites (ACCs) have gained significant research interest in recent years ACC is a class of biocomposites in which the matrix is a dissolved and regenerated cellulose, while the reinforcement is undissolved or partly dissolved cellulose This review paper is intended to provide a brief outline of works that cover recent progress in the manufacturing and processing techniques for ACCs, various cellulose sources, solvents and antisolvents, as well as their properties

https://www.mdpi.com/1420-3049/25/12/2836/pdf

All-Cellulose Composites: A Review of Recent Studies on Structure, Properties and Applications.

The present study aims to improve the reinforcement of hemp fibre to polypropylene (PP) by simple resin modification and fibre treatment. Maleic anhydride grafted polypropylene (MAPP) was used as resin modifier by direct mixing with PP, and hydrophobically modified hydroxyethyl cellulose (HMHEC) was used as fibre treatment reagent by immersing fibre into its aqueous solution. The influences of fibre content, resin modification, and fibre treatment on the mechanical properties (tensile, flexural, and impact strengths) of composites were investigated. The change of interfacial bonding between fibre and resin in composites caused by MAPP and HMHEC was studied by scanning electron microscopy and dynamic mechanical analysis. Resin modification and fibre treatment were effective to enhance the mechanical properties of the composites. The improvement in interfacial bonding is quantitatively evaluated with adhesion factor.

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Improvement of mechanical properties of noil hemp fiber reinforced polypropylene composites by resin modification and fiber treatment

Natural fibre-reinforced composites have attracted great research and economic interests because of their outstanding
'green' characteristics compared with glass fibre-reinforced composites. It is very important to understand the processing effect on the natural fibre-reinforced composites mechanical properties because of the natural fibre degradation characteristics. Optimizing the fabrication process, especially the compounding process, is effective to achieve the optimal properties of the composites. In this research a natural fibre, noil hemp fibre, was applied to reinforce polypropylene with internal mixing process. The influence of compounding parameters, such as mixing temperature, mixing time and rotor speed, on the mechanical properties (tensile strength, flexural strength and impact strength) of the noil hemp fibre/polypropylene composites was investigated using orthogonal method and the evidence of thermogravimetric
analysis test of fibre and the observation of fibre dispersion in resin. The range analysis and variance of analysis demonstrated that the mixing temperature has significant effect on the three mechanical properties, mixing time has minor influence on the tensile and flexural strengths, and rotor speed mainly affects the impact strength. The thermogravimetric analysis test of noil hemp fibre and the fibre dispersion in resin show that a combination of low mixing temperature, short mixing time and high rotor speed of compounding process is helpful to achieve certain fibre dispersion without serious thermal degradation of fibre. Noil hemp fibre/polypropylene composites with the best comprehensive mechanical properties could be obtained at 165 degree C for 12 min with rotor speed 50 r/min.

/pdf/fabrication-process-optimization-of-hemp-fibre-reinforced-1gd5mj00sf.pdf

Zili Yan

Papers

Improvement of mechanical properties of noil hemp fiber reinforced polypropylene composites by resin modification and fiber treatment

Fabrication process optimization of hemp fibre-reinforced polypropylene composites