Incorporation of bromo-octadecane into long-chain ester monolayers at the air/water interface

Surface compatibility of 2-methoxy ethyl stearate and oleate esters with 1-bromo-octadecane (RBr) has been investigated at the air/water interface with a Langmuir film balance. The methoxy ethyl head group in the esters promotes flat conformation at the air/water interface as observed from its higher surface area (stearate, 22.41 Å2/molecule; oleate, 57.20 Å2/molecule) in comparison to the corresponding acids. The stearate ester forms a homogeneous mixed monolayer with maximal incorporation of 0.5 mole fraction of RBr. This is indicated by the retention of liquid condensed and solid condensed phases of stearate ester, and the positive deviation of the mean molecular area of the mixed film from the calculated additive areas. When the mole fraction of RBr (x2) exceeds 0.5, the onset of formation of heterogeneous mixed film is indicated by the appearance of initial and final collapse pressures. On the contrary, oleate ester shows the least compatibility with RBr, which is indicated by the progressive decrease in mean molecular area with x2. The more liquid expanded-phase structure of oleate ester probably does not promote compatibility with RBr at the air/water interface

Influence of Novel Electron Beam Modified Surface Treated Dual Phase Filler on Rheometric and Mechanical Properties of Styrene Butadiene Rubber Vulcanizates

Abstract Rheometric and mechanical properties, hysteresis and swelling behavior of the Styrene-Butadiene Rubber vulcanizates (SBR) filled with unmodified and novel electron beam modified surface treated dual phase fillers were investigated. Scorch time increases for these modified filler loaded vulcanizates due to introduction of quinone type oxygen on the surface. Electron beam modification of dual phase filler in the absence of trimethylol propanetriacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) significantly improves the modulus of the SBR vulcanizates, whereas the values of tensile strength and elongation at break drop. However, presence of TMPTA or silane slightly increases the modulus with significant improvement in tensile strength. This effect is more pronounced at higher loading of these modified fillers in SBR vulcanizates. These variations in modulus and tensile strength are explained by the equilibrium swelling data, Kraus plot and a new mathematical model interpreting the polymer-filler interaction. Hysteresis loss ratio of SBR vulcanizates loaded with irradiated fillers in absence and presence of TMPTA or silane increases due to highly aggregated structure of the filler.</jats:p

Surface morphology of styrene-butadiene rubber vulcanizate filled with novel electron beam modified dual phase filler by atomic force microscopy

Topographic and phase imaging in tapping mode atomic force microscopy (TMAFM) has been performed to investigate the effect of unmodified and modified dual phase fillers on the morphology of and the microdispersion of the filler particles in the rubber matrix. The above fillers were modified using acrylate monomer (trimethylol propane triacrylate, TMPTA) or a silane coupling agent (triethoxysilylpropyltetrasulphide, Si-69) followed by electron beam modification at room temperature. Both unmodified and surface treated fillers were incorporated in a styrene-butadiene rubber. The phase images of the above composites show three levels of contrasts that correspond to matrix, filler aggregates, and bound rubber around the filler aggregates. Also, the images further elucidate the aggregated nature of the filler due to modification, which is more pronounced in the case of electron beam modified acrylated filler loaded rubber. The corresponding topographic images have been characterized by various statistical quantities like roughness parameters and one- and two-dimensional power spectral densities (1D-PSD and 2D-PSD). As compared to the control, significant increase in surface roughness is observed in the case of the modified dual phase filler loaded composites. The higher fractal value of these vulcanizates confirms the above fact. AFM study also suggests that the electron beam modification of the above fillers significantly increases the filler-filler and filler-polymer interactions

DFT theoretical and experimental investigation of gelatin-loaded niobium-doped calcium apatite ceramics to elucidate its structural and electronic characteristics

Owing to its ability to imitate the characteristics of natural bones, the biomedical community has extensively investigated the use of biphasic ceramic material comprising of hydroxyapatite (HAP) and tricalcium phosphate (β-TCP), for hard-tissue engineering purposes, particularly bone restoration. It is believed to enhance the material's breakdown process and promote the formation of new bone when combined with gelatin to produce a composite. However, this is contingent upon the material's electrical and structural characteristics. Gelatin/NbHAP (GNbHAP), and gelatin/HAP (GHAP) prepared by solvent casting differ in structural, and electronic properties. This difference is determined experimentally using characterization methods (such as X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Raman spectroscopy) and theoretically, using density functional theory (DFT) in the Gaussian 09 program utilizing the B3LYP functional method. XRD tests on the gelatin based HAP composites with and without niobium doping show that the composites are less crystalline, with weak crystalline peaks for gelatin, HAP, and niobium at their own 2θ values when they are pure. The FTIR measurements reveal the functional groups for the title structures under study. Several electronic parameters evaluated by theoretical study (DFT) show that GNbHAP induces significant changes in reactivity indices when compared to GHAP. Moreover, the GNbHAP composite is a better bioceramic material for hard-tissue engineering usage than the GHAP composite, as evidenced by alterations in the theoretical parameters including polarizability, dipole moment, and electric susceptibility

Transmogrifying waste blister packs into defect-engineered graphene-like turbostratic carbon: novel lithium-ion (Li-ion) battery anode with noteworthy electrochemical characteristics

The study discusses the preparation steps of turbostratic carbon with graphene-like features from the waste blister packaging materials. The prepared materials renders outstanding cycling stability, when used as an anode material in Li-ion batteries.</jats:p