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Extensive employment of biomaterials in the areas of biomedical and microbiological applications is considered to be of prime importance. As expected, oil based polymer materials were gradually replaced by natural or synthetic biopolymers due to their well-known intrinsic characteristics such as biodegradability, non-toxicity and biocompatibility. Literature on this subject was found to be expanding, especially in the areas of biomedical and microbiological applications. Introduction of porosity into a biomaterial broadens the scope of applications. In addition, increased porosity can have a beneficial effect for the applications which exploit their exceptional ability of loading, retaining and releasing of fluids. Different applications require a unique set of pore characteristics in the biopolymer matrix. Various pore morphologies have different characteristics and contribute different performances to the biopolymer matrix. Fabrication methods for bio-based porous materials more related to the choice of material. By choosing the appropriate combination of fabrication technique and biomaterial employment, one can obtain tunable pore characteristic to fulfill the requirements of desired application. In our previous review, we described the literature related to biopolymers and fabrication techniques of porous materials. This paper we will focus on the biomedical and microbiological applications of bio-based porous materials.

The properties of a thermoplastic blend depends on its constituent materials. Properties and applications vary for each thermoplastic blends, and a number of such materials have been fabricated in recent years. This review provides an in-depth discussion on the properties and applications of various thermoplastic blends. Recent works and articles are cited in this paper. These citations are ubiquitous in the development of thermoplastics blends and their applications.

The effects of chlorite bleaching on the properties of cellulose derived from oil palm empty fruit bunch (OPEFB) fiber were investigated in this work. Cellulose was extracted from oil palm empty fruit bunch fiber via chlorite bleaching, alkali treatment, and acid hydrolysis. Cellulose was extracted by varying the bleaching duration, which corresponded to 4, 8, or 12 h. Fourier transform infrared (FTIR) analysis showed that the lignin and hemicellulose were significant removed after the bleaching process, whereas no spectral differences were observed in the samples with the increase of bleaching durations. The main removal of the lignin and hemicellulose components had occurred during the bleaching process. There was only slight additional removal of lignin and hemicellulose during the further extraction process with alkali and acid hydrolysis. The peaks at 1740 cm-1 and 1246 cm-1 which represent hemicellulose and lignin, respectively, were not present in the final extracted cellulose. The cellulose yield contents did not increase with the increasing of bleaching duration from 4 h to 12 h. X-ray diffraction (XRD) analysis revealed that the crystallinity and the 200 peak of OPEFB had increased after the bleaching process. Analysis of the visible light transmittance of cellulose, after a bleaching duration of 12 h, demonstrated the highest transmittance due to the disintegration of the fibers. By increasing the bleaching duration, the temperature at 50% weight loss of OPEFB increased, suggesting that the thermal stability of cellulose had improved.

Well-aligned arrays of vertically oriented ZnO nanorods were synthesized using hydrothermal method using equal molar concentration of zinc acetate hexahydrate (Zn (CH3COO)2.6H2O) and hexamethylenetetramine (C6H12N4) at various deposition temperatures. The resulting nanorods were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), photoluminescence (PL), and UV-vis spectrophotometer. XRD and FESEM results indicate that the crystallinity improved for nanorods grown at 85 °C. The preferred growth direction of these nanorods is in (002) direction. However, the nanorods were grown at 55 °C shows poor crystalline characteristics. Typically, these nanorods have grown up to 1000 nm with the diameter range of 25-50 nm. The obtained ZnO nanorods exhibit a weaker UV emission peak located around ~380-390 nm and a relatively stronger yellow-red emission band located at 625 nm to 675 nm.

Recently, surface functionality and thermal property of the green nanomaterials have received wide attention in numerous applications. In this study, microcrystalline cellulose (MCC) was used to prepare the nanocrystalline celluloses (NCCs) using acid hydrolysis method. The NCCs was treated with TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl)oxy radical]-oxidation to prepare TEMPO-oxidized NCCs. Cellulose nanofibrils (CNFs) also prepared from MCC using TEMPO-oxidation. The effects of rapid cooling and chemical treatments on the thermo-structural property studies of the prepared nanocelluloses were investigated through FTIR, thermogravimetric analysis-derivative thermogravimetric (TGA-DTG), and XRD. A posteriori knowledge of the FTIR and TGA-DTG analysis revealed that the rapid cooling treatment enhanced the hydrogen bond energy and thermal stability of the TEMPO-oxidized NCC compared to other nanocelluloses. XRD analysis exhibits the effect of rapid cooling on pseudo 2I helical conformation. This was the first investigation performed on the effect of rapid cooling on structural properties of the nanocellulose.

Polylactides (PLA) based composite films modified with nanoclay content ranges from 0-30 wt% were fabricated using solvent casting method and the mechanical properties, water vapor permeability, oxygen barrier, thermal stability and optical properties were studied. The study showed that the addition of up to 15 wt% of clay has caused a significant improvement of tensile strength of the PLA/nanoclay composite film. However, the further increasing of nanoclay content of >15 wt% of nanoclay has caused a significant reduction in tensile, elongation at break and optical properties of PLA matrix. Both the oxygen and water permeability of the PLA/nanoclay composite film decrease with the increasing of nanoclay contents. Greater water barrier properties would be achieved if the high nanoclay contents of 10-30 wt% were dispersed homogenous within the PLA matrix. The addition of nanoclay greater than 10 wt% affected the appearance of the film (i.e. increasing the haze and ΔE). Thermal analysis result has proved that the melting temperature, crystallization temperature and glass transition temperature of the composite film only slightly affected by the addition of nanoclay due to the immobilization polymer chain in the composite film.

In this study microcrystalline cellulose (MCC) was oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. The treated cellulose slurry was mechanically homogenized to form a transparent dispersion which consisted of individual cellulose nanofibers with uniform widths of 3-4 nm. Bio-nanocomposite films were then prepared from a polyvinyl alcohol (PVA)-chitosan (CS) polymeric blend with different TEMPO-oxidized cellulose nanofiber (TOCN) contents (0, 0.5, 1.0 and 1.5 wt %) via the solution casting method. The characterizations of pure PVA/CS and PVA/CS/TOCN films were performed in terms of field emission scanning electron microscopy (FESEM), tensile tests, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The results from FESEM analysis justified that low loading levels of TOCNs were dispersed uniformly and homogeneously in the PVA-CS blend matrix. The tensile strength and thermal stability of the films were increased with the increased loading levels of TOCNs to a maximum level. The thermal study indicated a slight improvement of the thermal stability upon the reinforcement of TOCNs. As evidenced by the FTIR and XRD, PVA and CS were considered miscible and compatible owing to hydrogen bonding interaction. These analyses also revealed the good dispersion of TOCNs within the PVA/CS polymer matrix. The improved properties due to the reinforcement of TOCNs can be highly beneficial in numerous applications.

The properties of a composite material depend on its constituent materials such as natural biopolymers or synthetic biodegradable polymers and inorganic or organic nanomaterials or nano-scale minerals. The significance of bio-based and synthetic polymers and their drawbacks on coating film application is currently being discussed in research papers and articles. Properties and applications vary for each novel synthetic bio-based material, and a number of such materials have been fabricated in recent years. This review provides an in-depth discussion on the properties and applications of biopolymer-based nanocomposite coating films. Recent works and articles are cited in this paper. These citations are ubiquitous in the development of novel bionanocomposites and their applications.

Palm kernel shell (PKS) core fibers, an agricultural waste, were chemically modified using N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHMAC) as a quaternizing agent. The potential of quaternized palm kernel shell (QPKS) as an adsorbent for fluoride in an aqueous solution was then studied. The quaternized palm kernel shell (QPKS) core fibers were characterized using Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope (SEM). The effect of various factors on the fluoride sequestration was also investigated. The results showed that with an increase in the adsorbent amount and contact time, the efficiency of fluoride removal was improved. The maximum fluoride uptake was obtained at pH 3 and a contact time of 4 h. The adsorption behavior was further investigated using equilibrium isotherms and kinetics studies. The results from these studies fit well into Freundlich, Redlich-Peterson, and Sips isotherm’s with a coefficient of determination (R2) of 0.9716. The maximum fluoride removal was 63%. For kinetics studies, the pseudo-second order was the best fit for fluoride, with an R2 of 0.999. These results suggest that QPKS has the potential to serve as a low-cost adsorbent for fluoride removal from aqueous solutions.

This study examined the use of supercritical carbon dioxide (SC-CO 2 ) in the extraction of triglycerides from de-shelled Jatropha curcas L. seeds. A central composite response surface methodology (RSM) was employed to evaluate the effects of pressure, temperature and solvent-to-solid ratio (SSR) on total yield (TY), concentration of triglycerides ( C TG ) and recovery of triglycerides ( R TG ). In the experiment, SC-CO 2 extraction of 15 g ground, de-shelled Jatropha seeds at a CO 2 flow rate of 25 mL/min was investigated under various pressure (250–350 bar), temperature (313–333 K) and SSR (60–100) conditions. The proposed quadratic model well fitted the RSM-designed data, and the statistical analyses showed that both pressure and SSR are important parameters that will significant affect the quality of extracted oil. Under a pressure of 350 bar, a temperature of 325 K and a SSR of 82, the values of TY, C TG and R TG were 43.0%, 936.2 mg/g, and 98.1%, respectively.

Low density polyethylene (LDPE), carbon black (CB), and oil palm empty fruit bunch (OPEFB) fiber composites were prepared by melt blending and compression molded into sheets. The effects of incorporated fibers on the electrical conductivity, thermal conductivity, tensile properties, and thermal degradation of the composites were investigated. FTIR results suggest that the OPEFB fibers interact poorly with the polymer matrix and lead to a decrease in mechanical properties. The electrical conductivity of the composites decreased with increasing OPEFB fiber content. Despite the slight decline in conductivity, the composites still were sufficiently conductive relative to applications such as sensors and electromagnetic shielding after the fiber addition. Reduction in thermal conductivity by as much as 10.9% was observed with the addition of 20% OPEFB fiber into LDPE/CB composites. The thermal stability of LDPE/CB/OPEFB fiber composites decreased with increasing fiber content because of the low thermal stability of the incorporated natural fiber.

A photocatalytic fiber was prepared by modifying the surface of jute fiber with a Bi2O3/TiO2 composite. Maleic acid was used as an organic linker, and the coating process was conducted with heat-treatment at 240 °C. At first, the Bi2O3/TiO2 composite was synthesized by incorporating TiO2 nanoparticles onto a Bi2O3 phase. Subsequently, the photocatalytic fiber was prepared by incorporating the Bi2O3/TiO2 composite onto the surface of the fiber. The Bi2O3/TiO2 composite-modified fiber was characterized by field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-visible spectroscopy. The synthesized composite exhibited notably high photocatalytic activity under visible light irradiation of λ up to 420 nm, whereby it could decompose organic pollutants in the aqueous and gaseous phases. Because of increasing environmental concerns, this photocatalytic system could be an important candidate for decomposing organic pollutants.

This paper describes the preparation of poly(vinyl alcohol)/kenaf fiber (PVOH/KF) composites with entrapped urea. The major FTIR peaks of these composites could be identified. These composites are intended for agricultural applications as biodegradable mulches and could be potential carrier materials for fertilizer. The water solubility, release behavior, chemical properties, and thermal stability of the composites were evaluated. The composites lost 25% of their weight after 7 days in water. In a wet environment, urea was released from the composites through its dissolution in water, and around 57% of the urea was released from the composites in 24 h; Thermagravimetric analysis showed that these composites were stable up 150 C. These composites would be able to withstand rain and protect seedlings from the sun when applied in the field as mulches. For around three to four weeks, these biobased mulches could slowly disintegrate as the PVOH binder was gradually dissolved by moisture, releasing the kenaf fibers to serve as soil fertilizer without leaving any undegradable waste for disposal. Hence, they would not pose any risks to the land or biological systems.

The physico-mechanical properties of lignocellulosic kenaf fiber reinforced polyvinyl alcohol (PVA) biocomposite films were investigated. To improve the properties of the biocomposite, kenaf fibers were chemically treated separately in a single stage (with Cr2(SO4)312(H2O)) and double stages (with CrSO4 and NaHCO3) to improve the adhesion and compatibility between the kenaf fiber and PVA matrix. PVA was reinforced with various compositions of chemically treated kenaf fiber by using a solution casting technique. Microstructural analyses and mechanical tests were subsequently conducted. Scanning electron microscopic analysis indicated that chemical treatment improved the uniformity distribution of kenaf fiber within the PVA matrix. FTIR and XRD analyses confirmed the presence of chromium on the fiber surface. The tensile strength of PVA reinforced with chemical treated kenaf fiber was found to be higher than those reinforced with untreated kenaf. The Young’s modulus, flexural strength, and flexural modulus increased with fiber loading for both untreated and treated kenaf fiber reinforced PVA films. The double stage treated kenaf fiber showed better mechanical properties and lower moisture uptake than the single stage treated kenaf fiber.

In the present study, the feasibility and the practicability of two different approaches to the individualization of microfibrillated celluloses (MFCs) from oil palm empty fruit bunches were evaluated. Some properties of MFCs prepared by ammonium persulfate (APS) oxidation were investigated and compared with those extracted using sulfuric acid hydrolysis. Fourier transform infrared observation demonstrated that almost all the hemicelluloses and lignin were effectively removed after the sulfuric acid hydrolysis, which was substantiated by the disappearance of the characteristic peaks of these two noncellulosic components at 1735 and 1508 cm−1, respectively. However, a peak at 1735 cm−1 was observed in the spectrum of APS-oxidized MFCs because the products prepared by this treatment are stabilized by carboxyl groups instead of sulfate half-ester groups, which introduced by sulfuric acid. Furthermore, X-ray diffractograms of MFCs revealed the decrease in crystallinity after sulfuric acid hydrolysis but remained similar after APS oxidation. Thermogravimetric analysis was employed to determine the thermal stability of the treated fibers. In addition, the morphologies and diameters of MFCs were determined by field-emission scanning electron microscopy. MFCs formed by these two different techniques exhibited long and network-like fibrils with widths ranging from 8 to 40 nm. UV-Vis spectroscopy was used to monitor the optical transmittance of the nanocellulose suspensions.