Structure-property relationship was studied for fully aliphatic polyimides containing alicyclic dianhydride and diamine units. Rel-(1 0 R,3S,5-tetrone (DAn) was used as an unsymmetrical spiro dianhydride, and 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA) and bicyclo[2.2.2]oct-7ene-2,3,5,6-tetracarboxylic dianhydride (BOCA) were used as symmetrical non-spiro dianhydrides. 4,4 0 -Methylenebis(2-methylcyclohexylamine) (MMCA) and 5-amino-1,3,3-trimethylcyclohexanemethylamine (AMCH) were N-silylated, and reacted with the dianhydrides to prepare the fully alicyclic polyimides. The formation of the polyimides was confirmed by Fourier transform infrared spectroscopy. DAn-based polyimides showed higher solubility than the polyimides derived from CPDA or BOCA. This was explained based on the results of wide-angle X-ray diffraction (WAXD) analysis of the polyimides. The WAXD study showed that DAn-based polyimides have greater full width at half maximum (FWHM) and d-spacing values than the other polyimides. This indicates that DAn-containing polyimides have lower intermolecular order, decreased intermolecular interaction, and less close chain packing compared to the other polyimides. It is considered that the morphology of DAn polyimides is attributable to the unsymmetrical spiro structure of DAn that leads to bulkiness, irregularity, and non-linearity of the polyimide chains. Decomposition temperatures of the polyimides were investigated by thermogravimetric analysis (TGA) and UV-visible spectroscopy was performed to evaluate the optical transparency of the polyimides.
A series of novel di-α-aminophosphonate derivatives were synthesized by a one-pot method in the presence of PEG-H2 O under ultrasonic irradiation and were characterized by IR, (1) H NMR, (13) C NMR, mass spectrometry, and elemental analysis. The newly synthesized compounds were evaluated for their cytotoxic activities against the human lung cancer cell line H1299 and the human breast cancer cell line MCF7 in vitro by the MTT method. All compounds showed moderate cytotoxic activity on both cell lines, and compounds 4b and 4c showed marked activity.
We have performed microencapsulation of phenyl acetate using poly(urea-formaldehyde) as a shell material, and studied the effect of agitation rate, core/shell mass ratio, surfactant concentration, and reaction time on capsule characteristics such as size, shell thickness, and surface morphology. The formation of microcapsules was confirmed by FTIR and TGA, and capsule characteristics were studied by optical microscopy and FE-SEM. Capsule size and shell thickness reduced with increasing agitation rate. As the mass of shell material was increased, shell thickness and nanoparticles on capsule surface increased. Capsule size and shell thickness decreased with increasing the concentration of a surfactant. Increasing reaction time caused increased capsule yield and shell thickness.
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