Biocomposites from polyfurfuryl alcohol reinforced with microfibres and nanocellulose from flax fibres and maize stalks

This study is aimed at extracting cellulose and nanocelluloses (cellulose nanocrystals (CNCs) and cellulose nanofibres (CNFs)) from maize stalks and flax fibres. Both flax fibres and maize stalks are composed of cellulose, lignin, hemicellulose and extractives. The extraction of cellulose involves the removal of lignin, hemicellulose and extractives. The presence of these components in plant fibres hinders the extraction of cellulose and nanocelluloses. Prior to extraction of cellulose, the different concentrations (1 wt.%, 1.5 wt.% and 2 wt.%) of NaOH were optimised. However, chemical compositions and XRD results revealed that the treatment of flax fibres with 1.5 wt.% sodium hydroxide (NaOH) gives optimum results and this concentration was further selected for the extraction of cellulose. Cellulose was extracted by chemical treatments (sodium hydroxide (NaOH), sodium chlorite (NaClO2) and potassium hydroxide (KOH)) and a combination of chemical treatments and mechanical process (supermass colloider). The materials obtained after each treatment stage during the extraction process were characterised by different characterisation techniques such as Fourier transform infrared (FTIR) spectroscopy, environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results from the aforementioned characterisation techniques confirmed that cellulose was successfully extracted from flax fibres and maize stalks. Cellulose nanocrystals (CNCs) were extracted by sulphuric acid hydrolysis accompanied with ultra-sonication from cellulose obtained from flax fibres and maize stalks. The extracted CNCs were rod-like material with diameters and lengths in nanoscale and microscale, respectively. On the other hand, cellulose nanofibres (CNFs) were extracted by mechanical process (supermass colloider). The extracted CNFs were web-like material with diameters and lengths in nanoscale and microscale, respectively. The dimensions of nanocelluloses were measured by atomic force microscopy (AFM). Their dispersion was investigated by light polarised microscopy. The extracted nanocelluloses and cellulose were used to produce nanopapers and micropaper. Nanopapers mimic the traditional paper, the only difference of the nanopapers is that they are produced from high aspect ratio nanomaterials. Both nanopapers and micropapers were prepared by solvent evaporating method. Their thermal, optical and mechanical properties were investigated and compared. The mechanical and thermal properties of nanopapers produced from CNFs were better than those produced from CNCs and micropapers. On the other hand, nanopapers produced from CNCs were more transparent in comparison to nanopapers produced from CNFs and micropapers. Cellulosic fibres have attracted a considerable attention in composite materials due to their high tensile strength and tensile modulus. This study is focused on the development of biocomposites of polyfurfuryl alcohol (PFA) by in-situ polymerisation in the presence of acid catalyst (p-toluene sulphonic acid). Biocomposites were produced by reinforcing PFA with flax fibres (untreated and treated), nanoparticles and CNCs. The biocomposites reinforced with CNCs and flax fibres showed an improvement in mechanical, thermal and thermo-mechanical properties. On the other hand, biocomposites reinforced with nanoparticles obtained from treated maize stalks showed an improvement in mechanical and thermal properties while biocomposites reinforced with nanoparticles obtained from untreated maize stalks showed lower mechanical properties and decreased thermal stability

Analysis and remediation of phthalate ester plasticizers and their degradation products in the aquatic environment

M.Sc. (Chemistry)Please refer to full text to view abstrac

Recent insight into the biomedical applications of polybutylene succinate and polybutylene succinate-based materials

The development of biodegradable and biocompatible materials to replace non-biodegradable synthetic polymers has received significant interest in biomedical applications. Amongst all biopolymers, polybutylene succinate (PBS) possesses excellent properties, such as biocompatibility, easy processability, biodegradability, non-toxic, good mechanical and thermal properties, which makes it a suitable candidate to replace non-biodegradable synthetic polymers in biomedical applications. This review provides recent advancements, trends, and challenges for the utilization of polybutylene succinate (PBS) and PBS-based materials for biomedical applications, viz. drug delivery, tissue engineering, and biomedical devices. In addition, the design of medical devices from PBS using 3D and 4D printing is also presented. The market analysis, comparison of virgin PBS and synthetic polymer properties, as well as the end of service life, are summarized briefly. The current status, challenges, and future directions are also discussed

A Review on Bast-Fibre-Reinforced Hybrid Composites and Their Applications

The development of eco-friendly products to protect the environment has become a topical subject in the research and industrial communities. This is a result of strict environmental regulations necessitating the development of novel strategies to reduce our reliance on petroleum-based products, which exert a negative effect on our ecosystem. Bast-fibre-based hybrids have been extensively studied for various applications due to their eco-friendliness and cost effectiveness. There is a very limited number of review articles covering the properties and preparation of bast-fibre-based hybrid composites. This review is designed to provide an overview of the preparation and application of bast-fibre-based hybrid composites. It covers the thermal properties, mechanical properties, moisture absorption and flame-retardant properties of bast hybrid composites. This review not only summarises recent advances on the use and preparation of bast hybrid composites, it also presents a future outlook

Electrospun Alginate Nanofibers Toward Various Applications: A Review

Alginate has been a material of choice for a spectrum of applications, ranging from metal adsorption to wound dressing. Electrospinning has added a new dimension to polymeric materials, including alginate, which can be processed to their nanosize levels in order to afford unique nanostructured materials with fascinating properties. The resulting nanostructured materials often feature high porosity, stability, permeability, and a large surface-to-volume ratio. In the present review, recent trends on electrospun alginate nanofibers from over the past 10 years toward advanced applications are discussed. The application of electrospun alginate nanofibers in various fields such as bioremediation, scaffolds for skin tissue engineering, drug delivery, and sensors are also elucidated

Fabrication of a Polybutylene Succinate (PBS)/Polybutylene Adipate-Co-Terephthalate (PBAT)-Based Hybrid System Reinforced with Lignin and Zinc Nanoparticles for Potential Biomedical Applications

Polybutylene adipate-co-terephthalate (PBAT) was used in an effort to improve the properties of polybutylene succinate (PBS). The resultant blend consisting of PBS/PBAT (70/30) was reinforced with lignin at different loadings (5 to 15 wt.%) and zinc (ZnO) nanoparticles (1.5 wt.%). Hot melt extrusion and injection moulding were used to prepare the hybrid composites. The mechanical, thermal, physical, self-cleaning, and antimicrobial properties of the resultant hybrid composites were investigated. The transmission electron microscopy (TEM) results confirmed that ZnO was successfully prepared with average diameters of 80 nm. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed that there were interactions between the fillers and the blend. The tensile strength and elongation at the break of the resultant materials decreased with increasing the loadings, while the tensile modulus showed the opposite trend. The melting behaviour of the blend was practically unaffected by incorporating lignin and ZnO nanoparticles. In addition, the incorporation of fillers reduced the thermal stability of the materials. Furthermore, the incorporation of ZnO nanoparticles introduced photocatalytic properties into the polymer blend, rendering it to be a functional self-cleaning material and enhancing its antimicrobial activities