Chiosa Cletus Odili

The poor performance of neat polylactic acid (PLA) and gelatin has driven the development of co- electrospun composites in biomaterials to achieve enhanced functional properties. In this study gelatin extracted from Crocker fish scale was co-electrospin with PLA. The composite fibres were fabricated at 2-17 wt.% gelatin. The electrospun fibres were evaluated via scanning electron microscope (SEM), Fourier transform spectroscopy (FTIR), differential scanning microscopy (DSC), thermogravimetric analysis (TGA), and Tensile test. FTIR analysis of PLA/gelatin fibres showed a peak growth at 1525cm-1 and a shift in the amide III band from 1239 cm-1 to 1192cm-1, indicating hydrogen bonding and chemical interaction between PLA and gelatin. The thermogram of the PLA/gelatin scaffold revealed an enhanced thermal stability with peak thermal stability (324oC) attained at 14 wt.% Gelatin. The DSC further confirms the interaction of PLA (Tg 75 OC) and gelatin (49 OC), forming a single glass transition temperature (Tg) at 70 OC. There was a slight increase in Tg of the composite fibres as the wight fraction of the gelatin increased. The SEM showed a good morphology resembling the native extracellular matrix (ECM) of the body. The ultimate tensile strength and percentage elongation of the fibres declined with increasing gelatin content. The introduction of this gelatin into PLA resulted in improved physiochemical properties of PLA/gelatin fibres due to chemical interaction. Thus, this composite fibre could serve as a potential wound dressing material.

This chapter provides a comprehensive exploration of the fundamental chemistry of lignin, exploring its complex structure of diverse functional groups. It examines the biosynthesis of lignin in plants, highlighting variations among softwood, hardwood, and grass lignin, such as the three primary phenylpropane units—p-coumaroyl, coniferyl, and sinapyl. This chapter also covers key extraction methods, such as the kraft and sulfite pulping processes. It further covers the chemical modification techniques to enhance lignin properties. Advanced characterization tools such as NMR and FTIR are introduced to analyze lignin’s molecular composition by providing a thorough understanding of lignin’s chemical nature. This will lay the groundwork for its effective utilization in various applications.

Polylactic acid (PLA) and polyvinyl alcohol (PVA) are promising biocompatible and biodegradable materials for biomedical uses, yet they have limitations. Similarly, lignin is a precursor for carbon fiber but requires plasticizers to be spun into fibers. This hampers their use in areas like carbon fiber production and tissue engineering, thus the reason for this study. Lignin was extracted from the plantain stem, and a lignin blend with PLA and PVA was made and electrospun into fibers. Thereafter, the physiochemical properties of the composite fibers were analyzed. The XRD spectra revealed increased crystallinity in PLA/Lignin fiber. When 0.75 wt.% of lignin was added to PVA, a new peak and peak shift were formed in the composite fiber, indicating strong interaction. The crystallinity of PVA/lignin decreased from 71.5 to 60.1% when 0.25 wt. % of lignin was added. DSC showed miscibility of polymers and improved melting temperatures from 155 to 228 °C, for PLA/lignin (0.5wt.%) fiber, but a reduction in melting temperatures of PVA, with higher lignin content (149–143 °C). FTIR showed notable functional groups, typical of PLA, PVA, and lignin, such as the OH group between 3800 and 3459 cm⁻¹. The minor peak shift in PLA/lignin showed that the level of molecular interaction is less than that of PVA/lignin. PLA/lignin displayed better fiber morphology compared to PVA/lignin, where fibers became sheet-like with higher lignin content. The addition of lignin improved the tensile strength of PVA (0.7 to 2.7 MPa). Conversely, PLA/lignin’s tensile strength decreased, due to reduced load transfer efficiency. Overall, PVA/lignin and PLA/lignin composites exhibit potential as reinforcement materials for biopolymers and carbon fiber precursors, with PVA showing more promise for carbon fiber production due to robust polymer-lignin interaction.

The need for the use of suitable natural alternative materials to oil-derived carbon-based materials, largely because of carbon IV oxide emissions and the attendant global health and environmental impact, has led to the discovery of lignin, a biomass-derived material, as a precursor for carbon fibre (CF) manufacture and as a reinforcement for biologically derived polymers like polylactide (PLA) with a variety of biomedical and industrial applications. This study investigated the thermal, structural, and compositional properties of lignin extracted from the pseudostem of Musa paradisiaca L. (the plantain tree). Dried and milled plantain pseudostem was pretreated using diethyl ether. Lignin was extracted from the untreated and pretreated pseudostem samples using 5M HCl for 1 h at 200 °C and 250 °C (acid hydrolysis). The results revealed that lignin obtained from pretreated pseudostem at 200 °C and 250 °C possesses superior thermal stability, as shown by the thermogram, with a DTG_max of 429.97 °C and 442.62 °C in contrast to 397.22 °C and 382.53 °C for lignin from untreated pseudostem due to the removal of volatile impurities and unwanted constituents after pretreatment. The FTIR spectrum of the extracted lignin samples shows similar absorption bands, like 1703.4 cm⁻¹ (C=O–conjugated carbonyl group), 1606–1602 cm⁻¹ (C=C stretching–aromatic compounds, benzene ring), 1315 cm⁻¹ (C-O stretching–syringyl units), and 1200.2 cm⁻¹ (C-H stretching, guaiacyl units), with the pretreated biomass having higher transmittance (%) values, indicating increased purity after pretreatment. The results presented above showed that lignin has been successfully extracted and can serve as a potential precursor for the production of carbon fibre, thereby reducing dependence on fossil-fuel-based precursors, with a reduction in carbon dioxide emission pollution.

Partially absorbable suture is useful for orthopedic repair as it possesses the capacity to promote a balance between strength, degradation rate and minimal inflammation. Still, the availability of partially absorbable suture is scarce. So far, no study has examined the mechanical strength and anti-microbial properties of partially absorbable monofilament suture made of low-density polyethylene (LDPE)/polylactide (PLA)/chitosan (CHS); hence, the reason for this study with a view to improve knot strength, antimicrobial property and degradation rate. In this study, monofilament suture was extruded using different weight fractions of LDPE, PLA and CHS. In vitro degradation studies were carried out using phosphate buffer solution (PBS). Mechanical and morphological changes were also examined. A standard Fourier transform infrared spectral of 3433, 2909–2840, 1738, 1452, 1174, 1062, 706 cm⁻¹ were assigned to OH group, C–H stretch, C=O vibration of ester, CH₃ bending, alkyl ester and CH₂ stretch, respectively. Tensile strength of knotted neat LDPE (4.84 MPa) exhibited 48.7% improvement in LDPE/PLA/CHS (60/39.5/0.5). This suggests that a good knot can be achieved to 40% weight fraction of PLA. The monofilament suture also demonstrated better antimicrobial property as the monofilament, LDPE/PLA/CHS (60/39.5/0.5) and LDPE/PLA/CHS (50/49.5/0.5) covered 12.7 mm zone of inhibition which is greater than the standard 1 mm. The suture’s morphological phases show dark fibre-like rough surfaces with microstructural irregularities as PLA and CHS were added to the matrix, which is required for enhanced degradation. Thus, the partially absorbable suture produced in this study could serve as a suture for tendon repair.

Carbon fibers (CFs) are made mostly from a non-environmentally friendly polyacrylonitrile (PAN) and little from rayon. PAN-based CFs, require huge amount of energy for its production aside its contributions to the global CO₂ emission. Therefore, there is recourse to a more environmentally friendly sources of CFs biomass. Recently lignin has been recognized as a potential renewable raw material for carbon fibers to replace PAN-based. The magnitude and quality of CO₂ emission of lignin-based CFs are dependent on the processing route. On this premise; this review examines the various lignin-based CFs processing route adopted by researcher in the recent past to establish the most viable route with minimum carbon footprint emission. Outcome of the review shows that the major advantages of aromatic polymer (AP) generated precursor over PAN is the presence of higher quantity of guaiacyl units and oxygen content which makes the stabilization phase efficient and faster requiring less energy. Though there are several methods and options for the various stages of conversion of lignocellulosic biomass into CFs as highlighted in the study, establishing an optimum processing route will be a trade-off amongst various issues of concern; carcinogenic risk, carbon footprint emission, CFs Yield and mechanical strength of the CFs. Inferences from the study shows that the L-CF significantly produced reduced climatic impact in terms of CO₂ emission.

A way to avoid or minimize the side effect that could result in drug delivery to cells with increased efficiency and performance in the health rehabilitation process is to use biocompatible and biodegradable drug carriers. These are essentially biomaterials that are metallic, ceramic, or polymeric in nature. The sources of these materials must be biological in its entire ramification. The classification, synthesis, processing, and the applications to which these materials are put are the essential components of having suitable target cell drug carriers. This chapter will be devoted to discussing biomaterials suitable as drug carrier for use in the health-related matters of rehabilitation.