Extraction of Cellulose Acetate From Cajuput (Melaleuca leucadendron) Twigs and Sugarcane (Saccharum officinarum) Bagasse by Environmentally Friendly Approach

This study was carried out to investigate the extraction of cellulose acetate (CA) from cajuput (Melaleuca leucadendron) twigs and sugarcane (Saccharum officinarum) bagasse using an environmentally friendly method. At first, cellulose was extracted from cajuput twigs (CT) and sugarcane bagasse (SB) through prehydrolysis followed by soda (NaOH) pulping and elemental chlorine-free (ECF) bleaching. Later, the extracted cellulose was acetylated using iodine (I) as a catalyst. The obtained CA was characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermal gravimetric analysis (TGA), scanning electron microscope (SEM) and X-ray diffraction. FTIR and NMR analysis proved the replacement of free OH (hydroxyl) groups by acetyl groups. The degree of substitution (DS) showed the acetylation capability of cellulose extracted from CT and SB as well. The diameter of CA and its crystallinity index (CrI) were measured by SEM and X-ray diffraction, respectively. The diameter of CA extracted from CT was approximately 10 μm and it was approximately 20 to 30 μm for SB. The CrI of the CA extracted from SB and CT was 75.6 and 60.2, respectively. Furthermore, the thermal gravimetric analysis showed that CA extracted from CT and SB was thermal resistance. Therefore, CT and SB will be potential alternative resources for CA production using the mentioned medthod.

Influence of Acetylated Cellulose Nanocrystal Incorporated into Poly(e-Caprolactone) Nanocomposites on Its Thermal, Mechanical, and Physicochemical Properties

Poly(e-caprolactone) are synthetic biodegradable polymers that can potentially be used as biocompatible materials for biological applications. The purpose of this work was to investigate the effect of acetylated cellulose nanocrystals isolated from corncob waste loaded into poly(e-caprolactone) matrix blend on its thermal, mechanical, morphology, and crystallinity. The acetylated cellulose nanocrystal filler with various concentrations (namely 5, 10, 15, and 20%) was mixed with poly(e-caprolactone) matrix prepared using reflux method under N2 gas flow at 120oC for 10 min. Subsequently, the samples was characterized by thermal gravimetric analysis, DSC, tensile, Fourier transform infrared spectroscopy, tunneling electron microscope, SEM, and XRD to determine the thermal, mechanical, functional group, particle size, morphology, and crystallinity, respectively. Thermal gravimetric analysis and DSC analysis revealed that the thermal stability of poly(e-caprolactone) improved and the degree of crystallinity gradually increased with the addition of 10% acetylated cellulose nanocrystals, hence resulting in a higher Young's modulus. Fourier transform infrared spectroscopy results demonstrate that acetylated cellulose nanocrystal was successfully incorporated into poly(e-caprolactone) with an additional OH group. In addition, the particle size of 32 nm for acetylated cellulose nanocrystal and the formation of agglomeration was present based on TEM analysis, thus suggesting that acetylated cellulose nanocrystal was compatible as a reinforcing filler in the poly(e-caprolactone) matrix. SEM and XRD analysis suggests that the morphology was relatively smooth and higher crystallinity was achieved. The results of this research demonstrated the good feasibility of poly(e-caprolactone)/acetylated cellulose nanocrystal nanocomposites with improved thermal, mechanical, and physicochemical properties that were successfully prepared using simple and low-cost acetylated cellulose nanocrystal as a filler material.

Utilization of cajuput (Melaleuca leucadendron) twigs and sugarcane (Saccharum officinarum) bagasse agricultural waste for cellulose acetate production by environmentally friendly approach

This study was carried out to investigate the extraction of cellulose acetate (CA) from cajuput (Melaleuca leucadendron) twigs and sugarcane (Saccharum officinarum) bagasse using an environmentally friendly method. At first, cellulose was extracted from cajuput twigs (CT) and sugarcane bagasse (SB) through prehydrolysis followed by soda (NaOH) pulping and elementary chlorine-free (ECF) bleaching. Later, the extracted cellulose was acetylated using iodine (I) as a catalyst. The obtained CA was characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermal gravimetric analysis (TGA), scanning electron microscope (SEM) and X-ray diffraction. FTIR and NMR analysis proved the replacement of free OH (hydroxyl) groups by acetyl groups. The degree of substitution (DS) showed the acetylation capability of cellulose extracted from CT and SB as well. The cellulose diameter and its crystallinity index were measured by SEM and X-ray diffraction, respectively. Furthermore, the thermal gravimetric analysis showed that CA extracted from CT and SB was thermal resistance. Therefore, CT and SB could be potential alternative resources for CA production using the mentioned method.

Chitin Matrix and Ultrastructure of Phosphate-Shelled Brachiopods

Phosphate-shelled brachiopods differ in filter-feeding lifestyle, with Lingula anatina an active infaunal burrower, and Discinisca tenuis a shallow marine epibenthic animal. The shells of these biomineralized organisms are built of organophosphatic constituents, the organic fibres/sheets reinforced with calcium phosphate (Ca-phosphate) to provide a sophisticated ultrastructural robustness. This investigation studied the nature of organic fibres in order to improve our understanding of how design principles are relevant to biominerals. Unlike the powdered samples that were commonly used in previous studies, for the first time organic fibres were isolated and the shell fractions were purified, in order to study the content and nature of the biopolymer fibres. Ultrastructural analysis, thermal gravimetric analysis and spectroscopic analyses reveal that the core polysaccharide framework is composed of layers of β-chitin sheets that are coated with a fibrous protein matrix. The chitin matrix in Lingula shells, 26.6 wt.%, is about two-fold higher wt.% compared to Discinisca shells,12.9 wt.%. After thermal gravimetric analysis, skeletal imaging of these shells shows important differences. Discinisca contains just a single layer that is ~21.0 µm thick. In contrast, Lingula exhibits two separate layers: the thicknesses of the primary- and secondary-layers are ~20.3 µm and ~8.1 µm, respectively. Taken together, the data shows that the chitin matrix contributes to increased skeletal strength, making Lingula highly adapted for life as an active burrower. In comparison, Discinisca contains less chitin and lives as attached epibenthos in a shallow marine environment.

Thermal analysis of Li2-хNaxGe4O9 glasses crystallization

The glasses of lithium-sodium tetragermanate LiNaGe4O9 and solid solution Li1.8Na0.2Ge4O9 were prepared by quenching the melt and crystallized on heating. The glass crystallization was controlled by differential scanning calorimetry and thermal gravimetric analysis. The DSC measurements performed in the range 300–1200 K show that the crystallization of the glasses occurs through a single stage. There are no anomalies on TGA dependences. It is assumed that LiNaGe4O9 and Li 1.8Na0.2Ge4O9 glasses crystallize in accordance with a polymorphic mechanism.

Mechanical and thermal characterisations of low-density polyethylene/nanoclay composites

The improvements of the thermal, mechanical, morphological properties of low-density polyethylene (LDPE)/nanoclay (NC) composites were investigated. Low-density polyethylene (LDPE) with different NC contents 2 wt.% ( V f = 8%), 4 wt.% ( V f = 15), and 8 wt.% ( V f = 27) with a fixed particle size (300μm) were prepared by the melt mixing process. The thermal tests (thermal gravimetric analysis) were performed to monitor the thermal stability of LDPE composites. The mechanical tests such as tensile strength, Young’s modulus, and strain at break were studied. The results of the thermal gravimetric analysis (TGA) display significant enhancement in thermal stability as the loading of NC increased in pure LDPE. The results showed that the NC fillers could effectively improve the mechanical properties of LDPE by comparison to pure LDPE, the tensile strength of LDPE/8 wt.% of NC are increasing by about 17% while Young’s modulus is increased by about 39%. From DMA results, the storage modulus is enhanced with increasing of NC loading into the LDPE matrix. The results of SEM photographs indicate that the incorporation 8 wt.% of NC displayed the best particles dispersion in the LDPE matrix.

Superparamagnetic Behaviour and Surface Analysis of Fe3O4/PPY/CNT Nanocomposites

The superparamagnetic property of nanomaterials such as Fe3O4 has been considered to be promising for various applications. In this paper, Fe3O4/PPY/CNT nanocomposites were synthesized with utilizing natural iron sand by a coprecipitation method. The as-precipitated Fe3O4 NPs were combined with carbon nanotubes (CNTs) using conductive polypyrrole (PPY) as linking agents. The Fe3O4/PPY/CNT nanocomposites were systematically characterized by FE-SEM, EDS, XRD, BET, and FTIR. Furthermore, the effects of CNTs on magnetic and thermal properties of nanocomposites were investigated by VSM and thermal gravimetric analysis (TGA), respectively. The composites exhibited significant decrease of coercivity value with the content of CNTs increasing. The VSM result confirmed that Fe3O4/PPY/CNT nanocomposites were superparamagnetic. It was found that by increasing the amounts of CNTs, the magnetization of Fe3O4/PPY/CNT nanocomposites gradually decreased. The addition of CNTs is intended to improve the mesoporous property as proved by BET analysis which has the potential application as a nanocatalyst.