The New Approach to the Preparation of Polyacrylamide-Based Hydrogels: Initiation of Polymerization of Acrylamide with 1,3-Dimethylimidazolium (Phosphonooxy-)Oligosulphanide under Drying Aqueous Solutions

The new initiator of the polymerization of acrylamide, leading to the formation of crosslinked polyacrylamide, was discovered. The structure of the synthesized polyacrylamide was characterized by XRD, 1Н NMR, and 13С NMR spectroscopy. It was shown that 1,3-dimethylimidazolium (phosphonooxy-)oligosulphanide is able to initiate radical polymerization under drying aqueous solutions of acrylamide, even at room temperature. According to XRF data, the synthesized polyacrylamide gel contains 0.28 wt% of sulphur. The formed polymer network has a low crosslinking density and a high equilibrium degree of swelling. The swelling rate of polyacrylamide gel in water corresponds to the first order kinetic equation with the rate constant 6.2 × 10−2 min−1. The initiator is promising for combining acrylamide polymerization with the processes of gel molding and drying.

COMPARATIVE STUDY BY SOL-GEL ACRYLAMIDE POLYMERIZATION VIA MICROWAVE AND SOLID STATE SYNTHESIS METHODS IN (Er2-x Srx)Ru2O6 SYSTEM

We have studied the structural and morphological properties on the pyrochlore (Er2-x Srx)Ru2O6 system, for x = 0.0, 0.02, 0.05, 0.07, 0.10, and 0.15. Polycrystalline samples were prepared by solid-state reaction (SR) and sol-gel acrylamide polymerization (SGAP). Thermogravimetric Analysis (TGA) was used to follow the thermal transformations such as reagents decomposition, phase transformation, chemical stability, and volatilization of organic material of samples. The reagents and synthesized products by the different methods of synthesis were characterized using powder X-ray diffraction (XRD). All samples crystallize Er2Ru2O6 PDF (72-7620) in the cubic unit cell with Fd$\bar{3}$m (No. 227) space group and form a solid solution up to x = 0.15. Scanning electron microscopy (SEM) shows considerable variations and similitudes in sizes, very few phases and shapes of polycrystals can be observed. Polycrystalline samples prepared by solid-state reaction (SR) present a grain size varies between 77 nm to 250 nm.

Purification of Synthetic Oligodeoxynucleotides via Catching by Polymerization

Recently, large quantities of pure synthetic oligodeoxynucleotides (ODNs) are needed for preclinical research, patient use, and clinical trials. These ODNs are synthesized on an automated synthesizer. Typically, the synthesis of ODNs generates impurities including failure sequences, which are difficult to remove. The reason is that they have the same properties as the full length ODNs. Currently, ODNs purification technologies can remove those impurities, such as reverse phase high-performance liquid chromatography (RP HPLC), anion exchange HPLC, polyacrylamide gel electrophoresis (PAGE). However, all these methods are inconvenient or costly to scale up. To solve these problems, two non-chromatographic methods of ODNs purification by polymerization are developed. In the first method, during automated synthesis, the full-length ODNs are tagged with methacrylamide group via a cleavable linker while the failure sequences are not. The full-length ODNs are incorporated into a polymer through a copolymerization process, and failure sequences and other impurities are removed by washing. The full-length ODNs are obtained by cleaving from the polymer. In the second method, the failure sequences are capped by a methacrylated phosphoramidite followed by radical acrylamide polymerization and water extraction to retrieve the full-length ODNs. The purity of ODNs has been confirmed by RP HPLC. The identity of ODNs has been established by comparing with authentic ODNs and Matrix Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) analysis. These methods do not require any expensive equipment and materials. Therefore, they are useful for large-scale drug ODN purification.