Going green with bionanocomposites

Polymers play a great part in our daily lives and without them around, this world would be very, very different, if not impossible to live in. Nevertheless, most people do not even know what polymers are, or just how prevalent they are around us. Many a time, the term polymer is used to refer to plastics, but it actually comprises a larger class of natural and synthetic materials with a wide range of properties and applications. A variety of polymers exist in nature, such as cotton, cellulose, shellac, amber, silk, ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Synthetic polymers include polyethylene, polypropylene, polystyrene, synthetic rubber, neoprene, nylon, polyvinyl chloride (PVC), Teflon, silicone, polyacrylonitrile, and many others. Monomers are essentially the building blocks of the molecules that make up everything, living and non-living, naturally occurring and man-made. A polymer may contain thousands of monomers, or just a few. Each monomer affects how that polymer looks, tastes, smells and behaves

Synthesis and characterization of Cu@Cu2O core shell nanoparticles prepared in seaweed Kappaphycus alvarezii media

This study reports a synthesis of Cu@Cu2O core shell nanoparticles (NPs) in Kappaphycus alvarezii (K. alvarezii) media via a chemical reduction method. The nanoparticles were synthesis in an aqueous solution in presence of K. alvarezii as stabilizer and CuSO4.5H2O precursor. The synthesis proceeded with addition of NaOH as pH moderator, ascorbic acid as antioxidant and hydrazinium hydroxide as the reducing agent. The resulting nanoparticles characterized by using UV–vis spectrum, X-ray diffraction, Transmission electron microscopy, Fourier transform infrared (FT-IR) and atomic force absorption (AFM). The UV-visible spectra indicate to peaks at 590 nm and 390 which confirmed the formation of Cu@Cu2O-NPs. The XRD used in analysis of the crystal structure of nanoparticles. The morphology and structure of the K. alvarezii/Cu@Cu2O-NPs were investigated by TEM and AFM. The average size of Cu@Cu2O-NPs obtained were around 53nm that confirmed by using X-ray diffraction, TEM and AFM. The Fourier transform infrared FT-IR)spectrum suggested the complexation present between K. alvarezii and Cu@Cu2O-NPs

Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method.

The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe3O4) nanoparticles on talc layers using an environmentally friendly process. The Fe3O4 magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe3O4 precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing=0.94-0.93nm); therefore, Fe3O4 nanoparticles formed on the exterior surface of talc, with an average size of 1.95-2.59nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe3O4 nanocomposites may have potential applications in the chemical and biological industries

Sago starch based hydrogel prepared using electron beam irradiation technique for controlled release application

Carboxymethyl Sago starch (CMSS) is one of the natural polymers with high value as a polymeric device for medical application due to its potential as biocompatible materials. The monomer blending with modified natural polymers by irradiation technique has received wide attention due to the simple method of preparation, more promising material and free chemical residue in the product. CMSS/methacrylic acid (MAA) hydrogels were synthesized by Electron Beam irradiation at 2meV, 10mA. The objective of this study was to evaluate the ability of hydrogels from modified carboxymethyl sago starch CMSS for oral drug delivery. The hydrogels were characterized by FT-IR, TGA and DTG. The effects of the preparation conditions such as the,monomer composition and irradiation dose on the gel fraction of the synthesized hydrogel were investigated. The swelling properties of the hydrogel were carried out in acidic media, neutral and alkaline media at different temperatures (27˚C – 60 ˚C).The pH sensitive properties of CMSS/MAA hydrogel showed that it can be used as drug delivery devices due to suitability of pH response to the environment in gastrointestine tract

Preparation and characterization of carboxymethyl sago starch hydrogel

Hydrogel is a three-dimensional network of polymer chains that receives high attention in scientific research due to their potential in drug delivery, biomedical field and waste water treatment. In this study, carboxymethyl sago starch (CMS) hydrogel was prepared via crosslinking technique where CMS was dissolved in HCl solution under vigorous stirring to form gel. The effect of the percentage amount of CMS, concentration of the acid solution, reaction time and reaction temperature were the parameters that have been studied to identify the optimum condition of CMS hydrogel. It was found that 60% amount of CMS in 2.0M acid solution for 12 hours at room temperature were the optimum conditions for CMS hydrogel. The CMS hydrogel was characterized by using Fourier Transform Infrared (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). FTIR spectrum of CMS hydrogel shows an additional sharp absorption peak at 1723 cm-1 denote that the Na in CMSS being exchanged to H from hydrochloric acid solution. SEM image of CMS hydrogel shows a spongy surface with empty space called pores in structure and connected to each other to form networks. TGA curve shows that the maximum rate of thermal decomposition of CMS hydrogel is higher than CMS at 311.89 ºC with 60.22 % major weight loss. This could be due to the presence of the cross-linkages in the CMS hydrogel

An alternative synthetic approach for 1,3- benzoxazine derivatives

1,3-benzoxazine derivatives were synthesized in high yield using three-step synthetic technique by the condensation of 2-hydroxybenzaldehyde with aromatic amines, reducing the condensation products and replacing the usual formaldehyde with methylene bromide to achieve ring closure. The structures of the benzoxazines were confirmed by FTIR, 1H and 13C NMR spectra and Mass spectroscopy

Cerium oxide nanoparticles: green synthesis and biological applications

CeO2 nanoparticles (NPs) have shown promising approaches as therapeutic agents in biology and medical sciences. The physicochemical properties of CeO2-NPs, such as size, agglomeration status in liquid, and surface charge, play important roles in the ultimate interactions of the NP with target cells. Recently, CeO2-NPs have been synthesized through several bio-directed methods applying natural and organic matrices as stabilizing agents in order to prepare biocompatible CeO2-NPs, thereby solving the challenges regarding safety, and providing the appropriate situation for their effective use in biomedicine. This review discusses the different green strategies for CeO2-NPs synthesis, their advantages and challenges that are to be overcome. In addition, this review focuses on recent progress in the potential application of CeO2-NPs in biological and medical fields. Exploiting biocompatible CeO2-NPs may improve outcomes profoundly with the promise of effective neurodegenerative therapy and multiple applications in nanobiotechnology

Optimization of reaction conditions for preparing carboxymethyl cellulose from sago waste

Sago pulp (57% w/w) isolated from sago waste was converted to carboxymethyl cellulose (CMC) by etherification using sodium monochloroacetate and sodium hydroxide. The reaction was optimized against temperature, concentration and reaction time. The optimized product has a large degree of substitution (DS) of 0.821, which compared favorably to other forms of cellulose. Fourier Transform Infrared spectra (FTIR) were used to characterize the product and starting sago pulp. Digital photographs of sago waste and sago pulp showed the expected rough woody structure while that of the CMC generated from the pulp showed a smooth surface morphology

A study of N-isopropyl acrylamide (NIPAM)-based polymer gel dosimeter by using Raman spectroscopy

Polymer gel is a kind of radiation dosimetry system that has been applied widely in radiotherapy treatment. In this study, the samples of NIPAM-based polymer gel which posses a good potential as 3D radiation dosimetry are synthesized. The samples of polymer gel were irradiated up to 20 Gy by using gamma cell instrument with 60Co sources at a constant dose rate. Upon irradiation, then the chemical changes in polymer gel were characterized by using Raman spectroscopy. The polymerization was referred to an increment in Raman intensity at 815 cm-1, assigned for C-C stretching mode of NIPAM polymer gel, as the dose increased. The consumptions of the co-monomers were referred to a decrement in Raman intensities at 1025 cm-1 and 2353 cm-1 assigned for C=C stretching modes of NIPAM and BIS respectively, as the dose increased. Result shows that the amount of carbon single bonds increases while the amount of carbon covalent bonds decreases following irradiation

Synthesis and characterization of new 3,4-dihydro-2H-benzo- and naphtho-1,3-oxazine derivatives

New 1,3-benzoxazine and naphthoxazine monomers were synthesized using a modified step-wise technique in which formaldehyde was replaced with methylene bromide for ring-closure reaction in the last synthetic step. Salicylaldehyde and 2-hydroxy-1-naphthaldehyde were used as the aromatic aldehydes and 4-fluoroaniline, 4-butylaniline, hexamethylenediamine, p-phenylenediamine and 2-aminothiazole were used as the primary amines. Condensation of the aromatic aldehydes and the aromatic primary amines in absolute ethanol gives imine compounds which on reduction with sodium borohydride in methanol give 2-hydroxybenzylamines/2-hydroxynaphthylamines. Ring-closure reaction between 2-hydroxybenzylamines/2-hydroxynaphthylamines and methylene bromide in absolute ethanol gives the 1,3-benzoxazines and naphthoxazines in good yields. The structures of the new 1,3-benzoxazine and naphthoxazine monomers were confirmed by FT-IR, 1H NMR and 13C NMR spectral analysis, Mass spectroscopy (GC-MS) and elemental analysis. The mass spectrum of the synthesized compounds showed molecular ion peaks centered at m/z 229, 218, 316, 317, 444 and 268 which are equivalent to the molecular weights of the new synthesized compounds a, b, c, d, e and f, respectively. Results of elemental analysis also confirm the calculated result to be in agreement with the experimental result