Improvement in the Performance of Potato Starch Used in the Water-Based Drilling Fluid via Its Chemical Modification by Grafting Copolymerization

Increasing the thermal stability and resistance to bacterial attack (bioresistance) of the potato starch used in the water-based drilling fluid is the aim of this work. Four types of potato starch grafted with acrylamide and a mixture of each one with acrylic acid, 2-acrylamido-2-methyl-1-propane sulfuric acid and itaconic acid were synthesized by manganese (IV)-induced redox system at the suitable concentrations of initiator and monomer(s). FTIR spectroscopy was used to verify the grafting of monomers onto the starch. The effect of grafted starches on the rheological and fluid loss properties before and after aging of the water-based drilling fluid prepared with fresh water, 4% saline and the South applied method were investigated. The results showed that temperature and aging of fluid enhance the rheological and fluid loss control properties of water-based drilling fluids prepared in the presence of grafted starches. In other words, grafted starches are stable against thermal degradation and can be used in the formulation of water-based drilling fluids for drilling of deep wells

Synthesis and Use of Amphoteric Carboxymethylcellulose Graft Copolymers in the Environmentally-acceptable Water-based DrillingFluids as a Water-sensitive Shale Stabilizer

Water soluble amphoteric graft copolymers of polysaccharide were synthesized via grafting of cationic monomer onto the sodium carboxymethylcellulose ()CMC)( and then used as a shale stabilizer in the water-based drilling fluids. Accordingly, five types of CMC-graft copolymers with different ratios of acrylamide AM)( and diallyldimethylammonium chloride DADMAC)( were synthesized. Grafting of monomer()s)( onto the CMC was verified by FT-IR spectroscopy. Results showed that grafting percentage is strongly affected by the monomer type as well as the weight ratio of monomers. Synthesized CMC-graft copolymers were used in the formulation of water-based drilling fluid. Drilling fluid was then subjected to the rheological, fluid loss and shale recovery tests. It was found that ability of CMC in the shale stability enhances by grafting of cationic monomer onto CMC. Fluid loss is also controlled in the acceptable region in the presence of CMC-graft copolymers. Among graft copolymers, CMC-grafted with pure cationic monomer exhibited higher efficiency in the fluid loss control and more important in the shale stability

Core-shell γ-Fe₂O₃/SiO₂/PCA/Ag-NPs hybrid nanomaterials as a new candidate for future cancer therapy

In the current study, γ-Fe2O3/SiO 2/PCA/Ag-NPs hybrid nanomaterials were successfully synthesized and characterized. At first, prepared γ-Fe2O3 core nanoparticles were modified by SiO2 layer. Then they were covered by poly citric acid (PCA) via melting esterification method as well. PCA shell acts as an effective linker, and provides vacancies for conveying drugs. Moreover, this shell as an effective capping agent directs synthesis of silver nanoparticles (Ag-NPs) via in situ photo-reduction of silver ions by sunlight-UV irradiation. This system has several benefits as a suitable cancer therapy nanomaterial. Magnetic nanoparticles (MNPs) can guide Ag-NPs and drugs to cancer cells and then Ag-NPs can affect those cells via Ag-NPs anti-angiogenesis effect. Size and structure of the prepared magnetic hybrid nanomaterials were characterized using FTIR and UV-Vis spectra, AFM and TEM pictures and XRD data.</p

POSS

In this study, it was aimed to investigate octavinyl-polyhedral oligomeric silsesquioxane (OV-POSS) incorporation into natural rubber (NR)/butadiene rubber (BR) elastomer blends as a potential compatibilizer. The effects of OV-POSS loading levels on the thermal, mechanical, morphological, and dynamic-mechanical properties of elastomer blends were explored. Fourier-Transform Infrared Spectrometer (FTIR), Temperature Scanning Stress Relaxation (TSSR), and Differential Scanning Calorimetry (DSC) results revealed the conceivable effect of OV-POSS nanoparticles in the vulcanization through reacting with sulfur and/or elastomers. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and tensile test measurements supported the improvement of mechanical properties due to homogeneous dispersion at low loading levels. On the other hand, high amount of OV-POSS incorporation (7 and 10 phr) resulted in a decrease in mechanical properties, owing to the agglomeration of nanoparticles. According to contact angle and Dynamic mechanical analysis (DMA) results, it could be concluded that OV-POSS nanoparticles were localized at the interface of the elastomers and enabled the compatibilization of immiscible NR/BR blends