This research is focused on the study of the physical, chemical, mechanical, and thermal properties of a newly identified natural stem fiber, Cyperus pangorei. The chemical composition of Cyperus pangorei fibers (CPF) such as cellulose, lignin, ash, moisture, and wax contents was evaluated. Besides these, the fiber density was determined and the apparent diameter was measured using an optical microscope. Further, tensile, thermal, XRD, and FT-IR studies were performed to evaluate the suitability of the fiber as a reinforcement. The surface topography of CPF was analyzed using scanning electron microscopy (SEM). Encouraging properties such as increased stiffness, fiber texture, and higher thermal stability suggest the suitability of CPF as reinforcement in polymer matrices.

The morphological, physicochemical, mechanical and thermal properties of Veldt-grape stem fibre and wild date palm leaf stalk fibre are described in this work, which are seldom studied before. The botanical name of Veldt-grape stem fibre and wild date palm leaf stalk fibre are known as Cissus quadrangularis and Phoenix reclinata, respectively. The morphological analysis of vegetable fibres showed the presence of cracks, microvoids and impurities on the surfaces of Veldt-grape stem fibre and wild date palm leaf stalk fibre. Veldt-grape stem fibre possessed the lowest diameter and density of approximately 0.2668 mm and 1.2128 g/cm³, respectively, compared to wild date palm leaf stalk fibre. An X-ray diffraction and Fourier transform infrared analysis of Veldt-grape stem fibre and wild date palm leaf stalk fibre exhibited the presence of cellulose I_β with a crystallinity index of 30.9% and 38.8%, respectively. Wild date palm leaf stalk fibre contained high surface roughness in the range of 0.904 µm than Veldt-grape stem fibre (0.611 µm). Tensile tests displayed that wild date palm leaf stalk fibre has highest tensile strength of around 66 MPa, and Veldt-grape stem fibre has highest strain to failure of around 6% in comparison with other fibre. The thermogravimetric analysis indicates that thermal stability of Veldt-grape stem fibre and wild date palm leaf stalk fibre is better up to 230℃ and 250℃, respectively, which are well within the polymerisation process temperature.

The specific interest for the use of bark in materials, instead than for energy recovery, is owed to circular economy considerations, since bark fibers are normally byproducts or even waste from other sectors, and therefore their use would globally reduce the amount of refuse by replacing other materials in the production of composites. For the purpose of promoting their application in polymer composites, mainly under a geometry of short random fibers, bark fibers are extracted and treated, normally chemically by alkali. Following this, investigations are increasingly carried out on their chemical composition. More specifically, this includes measuring cellulose, hemicellulose, and lignin content and their modification with treatment on their thermal properties and degradation profile, and on the mechanical performance of the fibers and of the tentatively obtained composites. This work aims at reviewing the current state of studies, trying to elicit which bark fibers might be most promising among the potentially enormous number of these, clarifying which of these have received some attention in literature and trying to elicit the reason for this specific interest. These can be more thoroughly characterized for the purpose of further use, also in competition with other fibers not from bark, but from bast, leaves, etc., and pertaining to developed production systems (cotton, hemp, flax, jute, etc.). The latter are already widely employed in the production of composites, a possibility scantly explored so far for bark fibers. However, some initial works on bark fiber composites and both thermoplastic and thermosetting are indicated and the importance of some parameters (aspect ratio, chemical treatment) is discussed.

This paper investigated the tribological behavior of natural fiber-reinforced polyester composites. The Cyperus pangorei (CP) fiber and polyester were used as a reinforcement material and thermosetting matrix, respectively. The composites were fabricated using compression molding technique with 40 wt% of CP fiber. Technological properties such as density, hardness, and wear of the composite specimens were determined. The density and shore D hardness of the prepared specimens were 1.0176 g/cc ± 0.106 and 87.25 ± 4.1, respectively. A pin-on-disk wear test machine was used to conduct the dry sliding wear test with constant sliding distance; various sliding velocities of 1, 2, and 3 m/s; and a range of contact pressure of 0.13–0.38 MPa. After the wear test, the surface roughness of worn specimens was measured. The specific wear rate increased when the applied load was increased on the specimen. A non-linear decrease in coefficient of friction was observed with the combination of increasing contact pressure and decreasing sliding velocity. The morphological analyses were carried out using a scanning electron microscope for the worn specimens.