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The utilization of natural fibers rather than engineered filaments has turned into a subject of conversation in the composite industries. In this research, one of the natural fibers was synthesized from Pennisetum orientale grass and the surfaces were modified using sodium hydroxide (NaOH) chemically. Then they were used as reinforcement in vinyl ester polymer by different weight percentage (0, 5, 10, 15, 20, 25, and 30 wt%) for fabrication of composites. At different filler loading various mechanical properties were evaluated and discussed. The mechanical properties of the composites were observed to increase at beginning phase with increase in filler content till optimum (25 wt%) fiber loading and from there on declines. The composite at optimum fiber loading were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis and compared with untreated composites. The findings give manufactures and engineer a general idea to use this composite for weight reduction especially in automotive applications. [ABSTRACT FROM AUTHOR]

A kind of silicon-and-boron-modified phenolic–formaldehyde resin (SBPF) with excellent thermal stability was fabricated via a simple two-step method and used for the matrix of ablation materials. The structure and thermal stability of the modified phenolic–formaldehyde resins (PFs) were characterised. The results showed that boron and silicon elements have been incorporated into SBPF in the form of a chemical bond. Meanwhile, the cured products showed an increase in graphite structure and a decrease in disordered structure due to the incorporation of boron and silicon. Compared with the ordinary phenolic resin, the initial thermal degradation temperature and charring yield at 800°C of SBPF increased by 73°C and 15 wt%, respectively. Further, the modified PFs, nano-Al(2)O(3) powders, glass powders and vitreous silica fibres were used to obtain a novel ceramizable phenolic moulding composite. The morphology, chemical composition and ablative characteristics of the composites were explored. The results showed that a compact and homogeneous SiO(2)–Al(2)O(3) layer formed on the ablated surface and protected the carbonised matrix and fibres from further oxidation. Compared with the ordinary PF composites, the SBPF composites showed a highly decreased linear/mass ablation rates, indicating the synergistic effect of boron and silicon modification on the enhanced ablation property.

A novel organic crystal was prepared from l -lysine (Lly) and p-toluenesulfonic acid (pTS), which was grown from an aqueous solution by slow cooling method. The crystal system and the lattice parameters have been confirmed by single crystal X-ray diffraction studies. The FT-IR, FT-Raman, 1 H-NMR and 13 C-NMR spectral of the crystal have been recorded and analyzed. The spectral analyses confirmed the presence of various functional groups and the molecular configurations in LLTS crystal. The UV-Vis-NIR transmittance spectrum has been carried out which shows the cutoff wavelength around 280 nm. The thermal properties of crystal have been evaluated from thermogravimetric (TG) and differential thermal analysis (DTA). The melting point of grown crystal is fairly high, at around 259 °C. The nonlinear optical (NLO) properties of LLTS crystal were demonstrated by powder SHG experiment and also by quantum chemical calculations. The powder SHG efficiency of LLTS crystal is relatively low and very different from theoretical calculation results. [ABSTRACT FROM AUTHOR]

Zofenopril calcium (ZOF) is one of the newest angiotensin-converting enzyme (ACE) inhibitors, highly lipophilic and with low water solubility. This research investigates the interaction between ZOF and a chemically modified derivative of β-cyclodextrin, 2-hydroxypropyl-β-cyclodextrin (HPBCD), in order to prove the formation of an inclusion complex with an enhanced water solubility profile of ZOF. In this research, for the first time, the physicochemical characterization and the solubility profile of an inclusion complex between ZOF and HPBCD are reported. Different spectroscopic techniques (UV absorption spectrometry, powder X-ray diffraction, attenuated total reflectance Fourier transform IR spectroscopy) were applied in order to prove the formation of the ZOF/HPBCD inclusion complex, both in water and in the solid state, backed by thermal analysis (TGA/DTG/HF). The obtained results confirmed that the physicochemical properties of the ZOF/HPBCD binary system, prepared using the kneading method, are different in comparison to both with the parent substances and the corresponding physical mixture, thus suggesting that an inclusion complex was formed. After the formation of the inclusion complex with HPBCD, the solubility test indicated that the water solubility of ZOF was increased 5-fold. [ABSTRACT FROM AUTHOR]

Novel type of highly swollen beads were prepared by grafting 2-hydroxyethylacrylate onto biodegradable Sodium alginate (SA) via free-radical polymerization using potassium persulphate as an initiator and Triprolidine hydrochloride as a model drug. Evidence of grafting was obtained by fourier transform infrared spectroscopic technique. Morphological properties of the beads were studied by SEM analysis. Thermal properties and crystallinity of the beads were characterized using differential scanning calorimetry and thermogravimetric analysis and X-ray diffraction techniques, respectively. Dissolution experiments were performed to study the release profiles at 37 °C in phosphate buffer solution (pH-7.4). Effect of monomer content, crosslinking agent and drug/polymer ratio on swelling properties and release profiles were also comparatively studied. A dissolution result concludes that drug release decreases with increasing crosslinker content. The highest release (96%) was obtained for the beads prepared with 0.5 mL crosslinking agent. Equilibrium swelling degree also supports the drug release profiles confirming SA-g-HEA beads showed better release profiles compare to plain SA beads. [ABSTRACT FROM AUTHOR]

Abstract: Good transparent single crystals of l-phenylalanine l-phenylalaninium malonate (LPPMA) have been grown successfully by slow evaporation technique from aqueous solution. Single crystal X-ray diffractometer was utilized to measure unit cell parameter and to confirm the crystal structure. The chemical structure of compound was established by FT-NMR technique. The vibrational modes of the molecules of elucidated from FTIR spectra. Its optical behaviour has been examined by UV–vis spectral analysis, which shows the absence of absorbance in the visible region. Thermal properties of the LPPMA crystal were carried out by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) techniques, which indicate that the material does not decompose before melting. The melting point of grown crystal was observed as 180°C by melting point apparatus. The NLO property was confirmed by the powder technique of Kurtz and Perry. The dielectric behaviour of the sample was also studied for the first time. [Copyright &y& Elsevier]

Thermal and structural properties of three clays (sepiolite and two kaolinites) from Turkey were studied by thermal analysis (TG-DTA), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FT-IR), and surface area measurement techniques The adsorption of sulfur dioxide (SO) gas by these clays was also investigated. SO adsorption values of K1, K2, and S clay samples were measured at 20 °C and pressures up to 106 kPa. Sepiolite sample (S) primarily consists of pure sepiolite, only dolomite present as accompanying mineral. Both kaolinite samples, K1 and K2, mainly contain kaolinite as the major clay mineral and quartz as impurity. In K2 sample, muscovite phase is also present. Simultaneous TG-DTA curves of all clay samples were obtained at three different heating rates 10, 15, and 20 °C min over the temperature range 30-1200 °C. It was found that the retention value of SO by S clay (2.744 mmol/g) was higher than those of K1 (0.144 mmol/g) and K2 (0.164 mmol/g) samples. [ABSTRACT FROM AUTHOR]

Mg oxide powder has been synthesised by sol–gel process via a novel non-alkoxide route. The precursor Mg oxalate gel was characterised by morphology, pore size distribution and differential thermal analysis, Fourier transformation infrared, TEM, SEM and X-ray diffraction analysis. The TEM studies on this system are reported for the first time depicting a unique morphology. A comparison in the morphology and the dielectric constant values of the sol–gel derived MgO powder was carried out with MgO powder obtained by Mg ribbon oxidation process. The sol–gel derived MgO powder was characterised by dielectric constant measurement in the compacted form and it was observed to exhibit a dielectric constant value, quite matching with the polycrystalline MgO in thin film form. [ABSTRACT FROM AUTHOR]