Effects of fiber loadings and lengths on mechanical properties of Sansevieria Cylindrica fiber reinforced natural rubber biocomposites

© 2023 The Author(s). Published by IOP Publishing Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/In this present investigation, Sansevieria cylindrica fiber was used as a reinforcement in a natural rubber matrix. Various biocomposite samples with different fiber contents (lengths and loadings) were fabricated, using compression molding process and vulcanizing technique by maintaining the temperature around 150 °C. From the results obtained, mechanical properties: tensile strength, modulus elongation at break and tear strength of 10.44 MPa, 2.36 MPa, 627.59% and 34.99 N respectively, were obtained from the optimum composite sample with length and loading of 6 mm and 20 wt% composition, respectively. The maximum hardness was observed at 76.85 Shore A from the composite sample of 6 mm and 40 wt%. The optimum properties can be attributed to the presence of strong interfacial adhesion between the Sansevieria cylindrica fiber and the natural rubber matrix. The mechanisms of failure of the biocomposites at their interfaces were examined and analyzed, using scanning electron microscopy (SEM). The micrographs obtained from SEM further confirmed that the Sansevieria cylindrica fibers were surrounded with more amount of natural rubber which can exhibit strong interfacial bonding between fiber and matrix. The optimal composites of this work can be used in general, abrasion resistant conveyor belt.Peer reviewe

Type one segmental Darier′s disease

A 50-year-old woman presented with multiple pruritic hyperpigmented papules in a zosteriform pattern involving the abdomen and back on the left side and in a linear pattern involving the left arm and forearm of 2 years duration. Histopathology revealed striking suprabasal acantholysis and marked dyskeratosis in the form of corps ronds and grains, a picture consistent with Darier′s disease (DD). Type one segmental DD involving multiple sites in zosteriform and linear patterns is an uncommon condition and is reported for its rarity

Mechanical Properties of Epoxy Composites Reinforced with Areca catechu Fibers Containing Silicon Carbide

The physical and chemical attributes of Areca catechu fiber (ACF) were explored. ACF is attractive because of its high cellulose content at 63.2 wt%. The mechanical properties were evaluated for Areca catechu fiber-reinforced epoxy composites, in which silicon carbide (SiC) was used as filler. The studied properties included water absorption, flexural strength, impact strength, tensile strength, and hardness properties. The tensile and flexural properties improved when the filler content increased from 40 to 50 wt%, but further increment in the filler content reduced the strength values. The addition of SiC adversely affected the bending and flexural properties of the composites at 40 and 50 wt% filler content, but it positively affected the properties at 60 wt% filler content. The hardness of the composites increased with the addition of 10% silicon carbide. From the results of this study, it is recommended that the ratio of silicon carbide in the composite should not exceed 10 wt% due to agglomeration. The composites containing 10 wt% SiC can be used for outdoor applications such as decking, railing, garden fencing, cladding, and siding applications

Use of Hemp Waste for the Development of Mycelium-grown Matrix Biocomposites: A Concise Bibliographic Review

Mycelium from fungi can serve as the matrix or as a self-grown binder in a biocomposite. The reinforcing component may consist of various combinations of agro-based waste in short fiber or powder form. The complexity of their development is linked not only to the selection of the substrate, but also to the growth conditions of the mycelial material and its consolidation in a final form by the temperature increase that takes place. These materials have initially been proposed as a replacement for polystyrene foams, and the characterization is concentrated on compression performance and acoustic and thermal insulation properties. The present review concentrates on substrates that originated from the large productive system based on hemp (shives or hurds, waste fibers, and mats). Attention is paid to the performance obtained and to the amount of waste that is possibly employed to serve as the substrate

Physico-chemical characterization of Grewia Monticola Sond (GMS) fibers for prospective application in biocomposites

New fibers extracted from plant barks are a recent subject of investigation as possible fillers for polymer composites. In this work, Grewia Monticola Sond (GMS) fibers have been characterized from a morphological, chemical, and thermal point of view. This involved using a number of techniques, including Fourier infrared spectroscopy (FTIR), X-ray diffraction (×RD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), atomic force microscopy (AFM), and 13C nuclear magnetic resonance (NMR). Results indicated that GMS fibers have relatively high cellulose (55%), with 33.5% crystallinity index and a crystallite size of 4.89 nm, and lower hemicellulose (14%) and lignin (15%) contents. The fibers showed cellulose degradation onset at around 324°C, while kinetic activation energy (74.18 kJ/mol) is quite low. The roughness of the fibers was in the range expected for similar natural fibers, and they may be considered silky according to their kurtosis values. As for possible application in composites, they would definitely withstand process temperatures with thermoplastics. However, their not very high crystallinity and low crystallite size might suggest a limited strength, to be verified in future after optimizing GMS fiber extraction from bark

Physical, Chemical, and Mechanical Characterization of Natural Bark Fibers (NBFs) Reinforced Polymer Composites: A Bibliographic Review

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

Effect of Alkali Treatment on the Properties of Acacia Caesia Bark Fibres

As possible substitutes for non-biodegradable synthetic fibre, ligno-cellulosic fibres have attracted much interest for their eco-friendliness; a large number of them are already used for the production of green polymer composites. The search for further green candidates brings into focus other fibres not previously considered, yet part of other production systems, therefore available as by-products or refuse. The purpose of this study is to explore the potential of alkali treatment with 5% sodium hydroxide (NaOH) to enhance the properties of bark-extracted Acacia Caesia Bark (ACB) fibres. The microscopic structure of the treated fibres was elucidated using scanning electron microscopy (SEM). Moreover, the fibres were characterised in terms of chemical composition and density and subjected to single-fibre tensile tests (SFTT). Following their physico-chemical characterisation, fibre samples underwent thermal characterisation by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and their crystallinity was assessed using X-ray diffraction (XRD). This level of alkali treatment only marginally modified the structure of the fibres and offered some improvement in their tensile strength. This suggested that they compare well with other bark fibres and that their thermal profile showed some increase of degradation onset temperature with respect to untreated ACB fibres. Their crystallinity would allow their application in the form of fibres with an average length of approximately 150 mm, even in thermoplastic biocomposites

Effect of Alkali Treatment under Ambient and Heated Conditions on the Physicochemical, Structural, Morphological, and Thermal Properties of <i>Calamus tenuis</i> Cane Fibers

This study explores the effect of alkali treatment at ambient (25 °C) and elevated temperatures (100 °C) on the physicochemical, structural, morphological, and thermal properties of Calamus tenuis cane fibers (CTCFs) for the first time. Our purpose is to investigate their potential use as reinforcement in polymer composites, since cane fibers are generally known for their accurate and consistent geometrical orientation. Treatment with 8% (w/v) sodium hydroxide (NaOH) is carried out at ambient temperature and at 100 °C for 4 h. Chemical analysis and Fourier transform IR spectroscopy (FTIR) indicate some removal of non-cellulosic elements from CTCFs during alkali treatment, resulting in increased surface roughness, as confirmed by using SEM micrographs. This removal of non-cellulosic elements leads to an enhancement in the density of the treated CTCFs. Untreated and treated fibers are analyzed for maximum degradation temperature, thermal stability, and kinetic activation energy (Ea) using thermogravimetric analysis (TGA). In particular, Ea was considerably diminished with treatment and temperature. X-ray diffraction (XRD) results show an improved crystallinity index (37.38% to 44.02%) and crystallite size (2.73 nm to 2.98 nm) for fibers treated with 8% NaOH at ambient temperature. In conclusion, a general benefit was achieved by treating CTCFs, though the influence of increasing temperature treatment appears controversial