PREPARATION AND STUDY OF THE PROPERTIES OF THE COPOLYMER OF CYCLIC UNSATURATED BISMALEIMIDE WITH STYRENE

The paper is devoted to the study of regularities of radical copolymerization reactions of unsaturated cyclic N,N'-bisimides (M1) with styrene (M2), the study of dependence of copolymerization reaction rate, composition of obtained copolymers, composition and estimated molecular weight on the composition of the initial monomer mixture. With the increase of bismaleimide amount in the initial monomer mixture a decrease of copolymerization reaction yield and molecular weight of the obtained copolymers was observed. This fact can be explained by active participation of bismaleimide in chain transfer in radical copolymerization reaction. The composition of the obtained copolymers in all cases is rich in styrene links

Optical Nanocomposites Containing Low Refractive Index MgF2 Nanoparticles

Nanoparticles composed of magnesium fluoride were successfully introduced into polymer matrices used for the fabrication of planar optical waveguides. Optical layers without visible scattering were successfully prepared. The transparent nanocomposites were formulated by direct mixing of modified MgF2 nanoparticles with fluorinated co-polymer matrix or acrylate monomer mixture with a help of additional solvent. An addition of MgF2 nanoparticles results in decrease of refractive index and thermo-optic coefficient of the polymer but increases substantially the optical propagation losses for planar waveguide at 1547 nm.

Technology of Polymer Microtips’ Manufacturing on the Ends of Multi-Mode Optical Fibers

The technology of polymer microtips’ manufacturing on the ends of selected multi-mode fibers has been reported. The study’s key element was an extended description of technology parameters’ influence on the shape of these 3D microstructures. Basic technology parameters such as spectral characteristics of the light source, monomer mixture type, optical power, and exposure time were taken under consideration. Depending on those parameters, different shapes, sizes, and surface structures of microtips were obtained. The spectral characteristics of the light and optical power delivered to a monomer drop were identified as the most important parameters for the formation of the desired 3D shape of the microtip. Presented experimental results are the base for further studies directed to the application of these micro-elements in the fields of optical measurements and sensors’ technology.

Effects of Gut Microbiota and Ingredient-Ingredient Interaction on the Pharmacokinetic Properties of Rotundic Acid and Pedunculoside

Rotundic acid and pedunculoside are the most abundant constituents in Ilicis Rotundae Cortex, and possess lipid-lowering activity. In this study, we evaluated the pharmacokinetic interactions of rotundic acid with pedunculoside and other ingredients from Ilicis Rotundae Cortex with rotundic acid and pedunculoside, and preliminarily investigated the effects of gut microbiota on their pharmacokinetics using a pseudo-germ-free rat model. After a single oral administration of each monomer, a monomer mixture, and Ilicis Rotundae Cortex extract to the conventional and pseudo-germ-free rats, rotundic acid and pedunculoside were quantified in plasma by an UPLC/Q-TOF-MS/MS method. The systemic exposure (maximum plasma concentration and area under concentration-time curve) of two analytes in conventional rats were increased in an approximately dose-dependent manner. Oral administration of rotundic acid and pedunculoside in the forms of a monomer mixture and Ilicis Rotundae Cortex extract to the conventional rats significantly decreased the systemic exposure compared with the monomer groups, which demonstrated the existence of significant pharmacokinetic interactions. The pseudo-germ-free rats were prepared by nonabsorbable antibiotic treatment, and the systemic exposure of two analytes were significantly decreased and most of the “time to reach the maximum” values were delayed in comparison to conventional rats, therefore gut microbiota might serve as an efficient absorption promoter. These results provide a scientific basis for the clinical application of the two bioactive constituents and Ilicis Rotundae Cortex.

Influence of Gold Nanoparticles on the Luminescence of an Acrylated Isocyanonaphthalene Derivative

Dodecanethiol-functionalized gold nanoparticles were incorporated into the polymer matrix of diurethane-methacrylate monomer mixture in the presence of SiO2 nanoparticles (8 wt %) and a new reactive organic luminescent material ACAIN (1-N-(2-acryloyloxy-3-chloroprop-1-yl)-amino-5-isocyanonaphthalene, 1 wt %). This way, a new, probably multifunctional, polymer nanocomposite was obtained. It was shown that the addition of SiO2 nanoparticles enhances the fluorescent intensity of ACAIN by 1.5 times in the 450-550 nm spectral range. Furthermore, an additional fluorescence enhancement up to 4.5 times was observed when Au nanoparticles were added to this nanocomposite in a rather low (0.12 wt %) concentration.

Investigation of the effect of some variables on terpolymerization process of vinyl monomers in CSTR by design of experimental method

Aqueous slurry free radical terpolymerization of acrylonitrile (AN) with vinyl acetate (VAc) and a constant amount of 2-acrylamido-2-methylpropane sulfunic acid (AMPS) using K2S2O8/NaHSO3 redox initiator was carried out in a 15-l continuous stirred tank reactor at constant temperature (60°C) and atmospheric pressure. A three-level response surface method based on central composite design was applied to investigate the effect of VAc concentration (wt%) in monomer mixture, bisulfite- to-persulfate ratio in redox initiator system $\left( {\frac{{{\text{[HSO}}_3^ - ]}}{{[{{\text{S}}_2}{\text{O}}_8^{ - 2}]}}} \right)$ and bisulfite-to-monomer mixture ratio $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{{\text{AN}} + {\text{VAc}}}}} \right)$ on the monomer conversion percentage to polymer, intrinsic viscosity [(η)] and sulfur end groups (SEG) index of the prepared polymers. Experimental results showed that the optimum conditions for synthesis of AN-VAc-AMPS system can be addressed as VAc=9 wt%, $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{[{{\text{S}}_2}{\text{O}}_8^{ - 2}]}}} \right) = 9.6$ and $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{{\text{AN}} + {\text{VAc}}}}} \right) = 0.027.$ Monomer conversion percentage to polymer, intrinsic viscosity and SEG index under optimum conditions were 75%, 1.38 dl/g and 190, respectively. The synthesized polymer under these optimum conditions can satisfy the requirements for acrylic fiber production in which its characterization was confirmed with Fourier transform infrared spectroscopy, nuclear magnetic resonance, elemental analysis, X-ray diffraction, differential scanning calorimetry and scanning electron microscope.

Improving Composite Resin Performance Through Decreasing its Viscosity by Different Methods

The aim of this work was to present the different current methods of decreasing viscosity of resin composite materials such as (using flowable composites, lowering the viscosity of the monomer mixture, heating composites and applying sonic vibration) and furnish dentists with a basis that can provide criteria for choosing one or another to suit their therapeutic requirements. The four discussed methods proved that lowering composite viscosity improves its handling and facilitates its application to cavities with complicated forms, decreasing time for procedure and improving marginal adaptation. Other properties improved by decreasing composite resin viscosity were controversial between the four methods and affected by other factors such as composite brand and light cure unit.

Preparation and Characterization of Crosslinked Latex Nanoparticles by Differential Microemulsion Polymerization

The differential microemulsion polymerization was used to synthesize crosslinked latex nanoparticles. In this paper, 1, 3-butylene glycol dimethacrylate (1, 3-BGDMA) was used as a crosslinking agent respectively 0-6 weight% of monomer total. The polymerization was carried out using butyl methacrylate (BMA), butyl acrylate (BA) and methacrylic acid (MAA) as the monomer mixture. The thin film of latex nanoparticles were prepared by using spin coating method and have been dried at 100°C for 5 minutes. The amount of the crosslinking agent added in the polymerization was optimized and we found that the particle sizes fall in the range of 30-60 nm. Field Emission Scanning Electrons Microscope (FESEM) was demonstrated that the spherical image of uncrosslinked latex change to a wooden-like image when the crosslinking agent added in the polymerization.