In this study, the effect of extraction methods on the properties of Althea officinalis l. (marshmallow) fibers was investigated. For this purpose, obtaining the fibers from stem was done by water and chemical extraction. After the extraction process, mechanical and thermal properties of althea fibers were investigated and morphological structure was examined. Crystallinity indexes (CI) of fibers were determined. Scanning electron microscopy results revealed that extraction of althea officinalis fibers by alkali boiling in 5% NaOH solution led to removal of surface impurities and also according to X-ray diffraction results, crystallinity index of fibers was improved by 14%. Chemically extracted fibers showed 37% higher tensile strength when compared to water extracted fibers. Density measurements revealed that chemically retted fibers have higher density. Also, Fourier Transform Infrared Spectroscopy analysis showed that chemical extraction caused change of chemical composition by decreasing and/or disappearing of some peaks which belong to hemicellulose and lignin.

The aim is to explore the utilization of cellulosic fibers extracted from the Taraxacum Sect. Ruderalia, which is also known as dandelion, introduces a potential reinforcement for the green composite industry. This research is focused on the analysis of chemical, physical, thermal, and morphological properties of the Taraxacum Sect. Ruderalia fibers. Its lightweight (1.397 g/cm³) with the presence of an acceptable cellulose ratio (52.7%) and high crystallinity (69.59%) provide comparable tensile strength (57.36 MPa) and Young’s modulus (2.96 GPa) for Taraxacum Sect. Ruderalia fibers. The fibers are experimentally thermal resistant to 272°C according to TGA that may be profitable in extrusion processes in polymeric composite manufacturing. The average fiber diameter and wall thickness were optically 233 µm and 1.5 µm, respectively. Taraxacum Sect. Ruderalia fibers have a rough surface character with some irregularities such as porosities, particles, indentations, protrusions, and also the microfibrillar structure which can support mechanical interlocking with polymer in a composite system. With all these encouraging properties, Taraxacum Sect. Ruderalia fibers can be good alternative reinforcement for common cellulosic bast fibers in the development of ecologically friendly and sustainable polymeric-based materials.

The present work is planned to research the properties of fibers extracted from the stem of Malva sylvestris in detail. Cellulose and hemicellulose contents, surface atomic concentrations, surface chemical bonds and functional groups of Malva sylvestris fibers were determined by means of chemical characteristics. X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were utilized to further analyze the fibers. Fiber density measurement and single fiber tensile test were performed. Malva sylvestris fibers were found to be thermally stable until 301 C which is a key parameter when processing with thermoplastic polymers. Thermal analysis also showed a char yield of 30.31%. The relatively lower density (1.104 g/cm³) can make it usable for light-weight applications. The crystallinity index (60.9%), cellulose content (75.7%) and maximum degradation temperature (355 C) are comparable with both common and new natural cellulosic fibers. Morphological observations confirmed its rough surface in untreated form. Malva sylvestris fibers are confirmed to be an appropriate material in manufacturing of green composites as reinforcement and/or additive.

The objective of the present research was to investigate the efficiency of alkali treatment on obtaining fine banana fibers. The fibers were exposed to alkali aqueous solutions at different concentrations changing from 5 to 20 wt%. The acting mechanism of the alkali treatment is removing of non-cellulosic constituents and separating the fiber bundle into smaller elementary single fibers. The efficiency of the alkali treatments was analyzed with the help of optical observations, fiber diameter measurement, single fiber tensile test and determination of pectin component. Chemical, crystalline, thermal and morphological properties of the fibers were examined by FTIR, XRD, TGA and SEM, respectively. FTIR analyses proved the removal of non-cellulosic components such as hemicellulose and lignin after alkali treatment. Fiber diameter decreased with increasing concentration of alkali treatment. Tensile properties and crystallinity index are correlated with alkali concentration. However, cellulose structure of the banana fiber was altered at mild alkali treatments. Microscopic observations revealed the appearance of single elementary fibers from the fiber bundle of the banana. These experimental findings suggested that alkali treatment can play promising role to prepare lignocellulosic fibers for textile applications.