Nanocomposites, Natural Fibers, Biopolymers

Natural fibrous materials have been studied to address noise and high heat indices. But many of the existing studies about natural fibers did not sufficiently support their claims of better acoustical and heat insulating materials. Thus, this study investigated the surface morphology of easily available agricultural materials like coconut husks, banana pseudostem and sugarcane husk for their potential as sound absorber and thermal insulator. Fiber pads from the materials were constructed and analyzed for noise reduction coefficients, thermal insulating performance, water absorbing capacity and flame tolerance using the methods specified in the American Society for Testing Materials. Scanning electron microscopy (SEM) was used for analytical imaging of the agricultural materials. The morphology of the coconut husk revealed more diverse microporous cells with varying shapes and sizes compared to that of sugarcane husk and banana pseudostem. Noise reduction coefficients (0.80 dB and 0.92 dB), (0.75d B and 0.78 dB) and (0.50 dB and 0.35 dB) each at 800 Hz and 440 Hz, and heat reductions of 2.56 °C, 1.71 °C, and 1.24 °C were obtained from coconut husk, sugarcane husk and banana pseudostem, respectively. The coconut husk gave the highest water absorbing capacity and high flame tolerance of 56% compared to that of sugarcane husk (49%) and banana pseudostem (32.67%). Results indicate that porosity affects the noise and heat reduction indices of the fibers. The more porous the material is, the better its potential as sound absorber and thermal insulator.

The main aim of this study was to characterize cooked bagasse fi bers from Agave angustifolia Haw. The fi bers were characterized using scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray Diffrac-tion and chemical analysis. The tensile strength was also tested using fi bers with a uniform length (30 mm). The fi bers were light brown in color, with a mean diameter and length of 501 μm and 144 mm, respectively. Scanning electron microscopy images revealed elliptically shaped cells with varying lumen size. Holocellulose content was approximately 82.12 %, and total lignin content was approximately 20.69 %. Due to the crystallinity and lignin content, the fi bers proved to be thermo-stable until 220 °C. The mean values of tensile strength, Young's modulus, % strain (ε), and ultimate tensile strength were determined via mechanical tests. The results are comparable to those of other common lignocellulosic fi bers, confi rming their potential use as a reinforcing element in a polymer matrix to form a new biodegradable composite. Resumen: El objetivo principal de este estudio fue caracterizar las fi bras de bagazo cocido de Agave angustifolia Haw. Las fi bras fueron caracterizadas a través de microscopia electrónica de barrido, calorimetría diferencial de barrido, análisis termogravimétri-cos, difracción de rayos X y análisis químico. También se realizaron pruebas de resistencia a la tracción usando fi bras de longitud constante (30 mm). Las fi bras presentaron un color marrón claro, con diámetro medio de 501 μm y longitud media de 144 mm. Las imágenes del microscopio electrónico de barrido mostraron células de forma elíptica con diferente tamaño de lumen. El con-tenido de holocelulosa fue alrededor de 82.12 % y el contenido total de lignina de aproximadamente 20.69 %. La fi bra resultó ser térmicamente estable hasta 220 °C debido a la cristalinidad y el contenido de lignina. El esfuerzo de tensión, el módulo de Young, el porcentaje de deformación (ε) y el esfuerzo último de tensión fueron obtenidos de las pruebas mecánicas. Los resultados son comparables a los de otras fi bras lignocelulósicas comunes, lo cual confi rma que estas fi bras tienen potencial como refuerzo en una matriz polimérica para formar un nuevo compuesto biodegradable. Palabras clave: análisis térmico, composición química, cristalinidad, morfología, pruebas mecánicas.

A new wave of science innovation is based on something much smaller than ever before. Nanotechnology is the hottest buzz in laboratories around the world. Scientists are using this cutting edge technology not only to develop incredible new products, but also to work towards cleaning water. Recently, heavy metal contamination has develop to be the essential serious ecological issues. The treatment of heavy metals is of special concern in the environment. As of late, different techniques for removal of heavy metal ions from wastewater have been widely considered. Adsorption is a standout amongst the most simple and productive process for treating industrial effluents, and a helpful mechanism to safeguard the ecosystem. The uses of novel nano-adsorbent for the treatment of waste water are confirmed by the continuous increment in research articles publication on adsorption of heavy metal ions using organic-inorganic nanocomposites. The present article highlights the late advancements in the preparation of nano adsorbents incorporating polymer-silica hybrid materials by sol-gel technique. The primary goal of the present review is to depict the versatile nature of polymer-silica hybrid materials and their ability to absorb variety of heavy metal ions which are present in the wastewater. An endeavor is likewise being made to incorporate adequate data like the strategy for synthesis of polymer-silica hybrid materials, structure, their adsorption capacity, variables affecting the adsorption and the plausible mechanism involve in adsorption of heavy metal ions from contaminated water.

PLLA is a thermoplastic biopolymer and can be
used in industrial applications for medical and filtration
applications. The brittleness of PLLA is attributed to slow
crystallization rates and its glass transition temperature
(Tg) is high (60 °C); for this reason, its applications are
limited. The orientation, morphology, and crystal structure
of the electrospun fibers was investigated by SEM, POM,
DSC, FTIR, XRD, and SAXS. Combining with additives
leads to a large decrease of fiber diameter, viscosity, and
changes of fiber morphology and crystal structure compared
to pure PLLA. DSC showed that the Tg of PLLA
decreased about 15 °C and there was no change in relaxation
enthalpy by the addition of plasticizer. FT-IR indicate
a strong interaction between PLLA and additives; a new
band appears in the PLLA blend at 1,756 cm−1 at room
temperature as a crystalline band without any annealing. In
addition, WAXD indicated that the intensities of the two
peaks at (200/110) and (203) increased for the blend at
room temperature without any annealing in comparison
with PLLA; this means that PHB crystallizes in the amorphous
region of PLLA. The POM experiments agree with
the results from DSC, FTIR, and WAXS measurements,
confirming that adding PHB results in an increase in the
number of nuclei with much smaller spherulites and
enhances the crystallization behavior of this material,
thereby improving its potential for applications.

The development of biocompatible patches that can provide adequate mechanical properties and mimicking the physiological relevance still has enormous challenges in the field of tissue engineering. In this study, the aim is to engineer and develop tri-layered nanofiber patches to synchronous the mechanical properties and mimic the complex structure of living cardiovascular tissues. The developed patches consisting of blended silk fibrin (SF) and polyvinyl alcohol (PVA) composite as a hydrophilic middle layer. The upper and lower layers were composed of polycaprolactone polymer (PCL) and Poly lactic acid (PLA), respectively. Layer by layer of the developed patches were fabricated by electrospinning technique. The patches characteristics such as morphology, surface topography, and physiochemical, biodegradable and mechanical stability were investigated. Furthermore, a human endothelial cell line (EA. hy926) was exploited to assess the biological properties of the fabricated patches. The results show that the patches had high endothelial cells biocompatibility, mechanical elasticity, and unique nanofibers structure.

Natural fibers like palm fibers provides new hope for researchers to compete with hazardous synthetic fibers with its excellent chemical and physical properties This work investigates the extraction of various fibers that are available from various portions of the palm tree and to characterize its chemical and physical properties. Also the results were compared with other natural fibers.

Copper oxide nanoparticles (CuO NP) were prepared using melanin as a stabilizing agent, and the CuO NP was used to prepare functional agar/CuO NP nanocomposite films using a solution casting method. The CuO NP was roughly spherical and was stable in aqueous solution. The CuO NP was homogeneously dispersed in the polymer matrix to form agar/CuO NP composite films. Incorporation of CuO NP increased the UV light barrier property with a little sacrifice of the film transparency. The mechanical properties of the films did not change significantly by the addition of CuO NP. Incorporation of CuO NP reduced the water barrier property, while increasing the surface hydrophobicity of the nanocomposite films. The agar/CuO NP nanocomposite films exhibited potent antibacterial activity against food-borne pathogens, E. coli and L. monocytogenes.

The objective of this work was to evaluate antibacterial and antibiofilm activity of Eucalyptus camaldulensis EO-loaded PLA nano-fibers. Different concentrations of E. camaldulensis EO (7.5, 10 and 15%) were incorporated into PLA nanofibers via an electrospin-ning technique. The nanofibers are characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA). Antibacterial activity of essential oil-loaded PLA nanofibers against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis were investigated by disc diffusion method. The antib-iofilm activity of essential oil-loaded PLA nanofibers was studied against Pseudomonas aeruginosa. The results obtained from the biofilm formation test revealed that PLA essential oil inhibited the Pseudomonas aeruginosa biofilm by 9.3%, 12.8% and 12.6%, respectively. Drug releasing behavior of essential oil-loaded PLA nanofibers was investigated by UV-Visible spectroscopy. According to releasing results, as the amounts of Eucalyptus camaldulensis essential oil in PLA nanofibers increased, the releasing decreased. The essential oil-loaded PLA nanofiber successfully delivered about 160 h.

Industrially, harvesting of the microalgal biomass is a techno-economic tailback, which essentially meant for the algal biomass industry. It is considered energy as well as cost-intensive in view of the fact that the dewatering process during harvesting. In this review chemical reactions involved in the flocculation of microalage biomass via various certain principal organic polymers are focused. Besides, it focuses on natural biopolymers as flocculants to harvest the cultivated microalgae. Commercially, bio-flocculation is suitable and cost-effective in the midst of a range of adopted harvesting techniques and the selection of an appropriate bioflocculant depends on its efficacy on the several microalgae strains like potential biomass fixation, ecological stride and non-perilous nature. The harvesting of toxin free microalgae biomass in large quantity by such flocculants can be considered to be one of the most cost-effective performances towards sustainable biomass recovery.

In recent years, natural fiber-reinforced composites are finding new applications in many sectors as they can yield economic, environmental and social benefits. In certain industries, such as building and transport, reduced material flammability is a key requirement. The aim of this paper is to examine, flammability property on Naturally Woven coconut tree leaf sheath (CLS) reinforced Phenol Formaldehyde (PF) composites. CLS composite were prepared in both treated and untreated forms with volume fraction of 60% of sheath and 40% of Phenol Formaldehyde resin. CLS were chemically treated using 5% of NaOH and composites plates were prepared by using a hydraulic hot press at 1400C. Flammability of these composites was evaluated using Underwriters Laboratory test (UL 94) and limiting oxygen index (LOI). The UL flammability tests include a standard burning test applied to vertical (UL 94 V) and horizontal test (UL 94HB) bars from which a general flammability rating is derived. In treated composites, the mass loss rate and flame propagation rate of treated composites has been decreased and resistances to flame has been increased and it is proved in both UL 94 V and UL 94HB tests. And in Limiting oxygen index test, alkali treated composites requires more oxygen than untreated composite material to burn. The result obtained revealed that the alkaline treated CLS fiber with PF resin has more compatibility. Hence treatment of CLS fibers will improve the flammability of the composite material indicating that, materials have promising applications in construction and decorative purposes.

The handicraft sector plays a significant role in providing employment opportunities in rural and semi-urban areas of the country. It helps in generating substantial income for the artisans. The uses for palm leaves are abundant. Attractive items made of Palm Leaves are very popular in South India, mostly in Southern Andhra Pradesh and Tamil Nadu. However, to generate sustainable revenue through their products, the artisans need to understand the buyer's requirements. This study aims to understand the consumer's purchasing behavior when buying palm leaf products. The sample consists of 233 consumers with diverse backgrounds from the state of Tamil Nadu, India. A questionnaire was developed to measure awareness and attitude influence while purchasing palm leaf products. The results can help the artisans to get an insight into end-user expectations and requirements toward palm leaf products and suggest strategies to increase the income of artisans.

PHB is a thermoplastic biopolymer produced by fermentation of renewable resources. Secondary crystallization during storage leading to an increased degree of crystallinity is a principal reason of PHB brittleness. In addition, pure PHB has no residues of catalysts, meaning low nucleation density and slow crystallization rates, leading to the formation of large spherulites with cracks and brittleness. To overcome the brittleness of PHB, polymer composites based on PHB,
plasticizers, and nano-clays A and B were prepared by solvent casting. The addition of plasticizer decreases Tg from 5 to -13 C in all composites. Furthermore, the addition of nano-clays acts as a nucleating agent to PHB. The effect of nano-clays A and B on spherulites morphology, thermal behavior, and crystal structure of PHB composites were tested by several techniques. Differential scanning calorimetry analysis shows that the addition of nano-clay A does not change the crystallization temperature and the crystallization half-time (t1/2) of the PHB matrix but that nanoclay B accelerates the crystallization process. Thermogravimetric analysis revealed
an increase in thermal stability of composites containing nano-clay B. Polarized optical microscopy showed that nano-clays serve as nucleating agents in PHB matrix. Therefore, the spherulites become smaller and the nuclei density increases at the selected crystallization temperature, compared to pure PHB.

Nowadays, the use of natural fibers for the manufacture of new composite materials is already being used in various engineering fields. This has motivated research in science and technology of traditional natural fibers such as sisal, jute, among others, which have promising characteristics. In this sense, this work presents the dog wool as a new fiber option, which is being discarded, for its use in the manufacture of composite materials. At present this fiber is being discarded as waste, thus causing environmental pollution. The characterization and the chemical treatment on the fiber were performed at the Textile Engineering laboratory – UFRN. Initially the fibers were pre-treated in a solution of sodium carbonate (Na2CO3) for the removal of wax, oil, cosmetic products that are being used for the treatment of the same as well as dust and other types of dirt present on its surface. The scanning electron micrographs (SEM) show the absence of impurities after the chemcial treatment. Fibres were classified of their physical structure, length and uniformity were performed.

We have succeeded in fabricating chitin nanofibers with uniform width of 20-30 nm from shrimp shell wastes using simple blending treatment under acidic condition. This process is simple, straightforward and does not require any sophisticated equipments for mass production of nanofibers. The obtained nanofibers are dispersed widely enough throughout transparent polymer matrix; the Young's modulus of the resin improves from 0.03 GPa to 3.34 GPa, with the resulting composite material retaining its transparency. It is worthy to note that the thermal expansion of the neat resin reduced drastically from 213 ppm/K to 20 ppm/K when 26% of shrimp shell chitin nanofibers are added. Chitin nanofibers reinforced composites with high light transmittance; mechanical strength along with low thermal expansion could be excellent substrate in the manufacturing of various optoelectronic devices such as flat panel displays and solar cells and is noteworthy for sustainable utilization of shrimp shell wastes.

This paper aims the 3-point pushup resistance analyze of polymeric composites reinforced by in natura vegetal fibers produced at South Bahia, Brazil. For the pushup resistance analyze, standardized specimens were produced following the ASTM D790-10 standard, cured at temperatures of 60°C, 80°C and 100°C for 24 hours in stove, being submitted to the specified test governed by the corresponding standard. Based on the in natura particulated fibers content incorporation ranging, the best formulation that purpose the best results in comparison with the developed groups was determined. It ponders the use of that material for defense industry applying as anti-riot equipment input.

Compressed stabilized earth blocks are the innovation of building materials replacing the earth blocks commonly called adobe. Common stabilizers (cement and lime) have been found to be expensive and harmful to the environment. Finding a natural, available, environmentally friendly stabilizer is vital. The objective of this study was therefore to assess the effects of gum Arabic (GA) as binder on the durability properties of laterite blocks. Compressed laterite blocks were stabilized with 2% and 6% respectively as total percentage of binders in the blocks (cement and/or GA). The results showed that GA improved the abrasion and drop resistances of compressed blocks. It has been found that the abrasion resistance of compressed blocks increased with the increase of GA content and the decrease of cement content. For instance, the mass abraded away of blocks stabilized with cement only was reduced up to 95.18% when GA was used to partially replace cement. As for drop test, the higher the content of GA the higher the resistance of blocks to drop.

Context: Hypericum perforatum L., commonly known as St. John’s wort, is practised as an alternative medicine against depression. Conversely, its remedial efficacy is indulged by various adverse effects that are recuperated in formulating nanoscaled commercial capsules encased by the biopolymer chitosan. A potential application of nanoencapsulation with regards to polymer enhances a slow controlled release of the targeted drug to achieve the desired delay until the right stimulus is obtained.

Aims: To value synthesizing biopolymeric nanocomposites encapsulating St. John’s wort commercial capsules substantiating it with a study of animal model of depression to endorse the effect of nanocapsulated drug as an effective brain drug.

Methods: The nanoparticulated suspension was prepared by ionic gelation technique and characterized to attest its antidepressant activity by in vivo studies.

Results: The drug binding efficiency was endorsed by FT-IR studies and the nanoparticles were characterized by an average particle size of 211.4 nm with a positive zeta potential of 45.9 mV. The animal despair studies on depression induced mice models displayed a significant difference in the immobility time during force swimming and tail suspension test. The commercial capsules were administed orally (p.o., 50 and 100 mg/kg). The animal despair studies were substantiated with affirmative biochemical assessments like SOD, CAT, GPx, GSH and LPO and compared with control groups.

Conclusions: The outcomes of this work manifest the calibre of St. John’s wort nanocomposites in a lower dosage that can alleviate depression and reduce side effects.

Destructive methods, viz. tensile test, bending test, water absorption test, chemical absorption test, and biodegradable test of woven sheep fiber reinforced with 40% and 50% epoxy composites, were studied at different operating conditions. The present investigation is focused on the physical and chemical characterization of the sheep wool fiber-reinforced polymer-matrix composites. Result shows that tensile and bending tests of woven sheep fiber composite of composition (50–50) have high strength and maximum bending compared to woven sheep fiber composite of composition (60–40). The (50–50) composition is having more moisture absorption than (60–40) composition, whereas (60–40) composition has more chemical absorption than (50–50) composition. Biodegradable test shows that compositions (50–50) and (60–40) after few days gain almost the same amount of weight. Destructed surfaces were examined using scanning electron microscope.