Syntheses and specific interactions of poly(hydroxyethyl methacrylate-b-vinyl pyrrolidone) diblock copolymers and comparisons with their corresponding miscible blend systems

Synthesis of gum tragacanth-grafted pentapolymer hydrogels for As(III) exclusion: Roles of microwaves, RSM optimization, and DFT studies

Microwave assisted homogeneous heating, selectivity in radical formation, and the faster polymerization facilitate the synthesis, structures, properties, and the higher branching associated stability of multifunctional multipolymers. Thus, the optimum gum tragacanth (GMTR)-grafted pentapolymer hydrogel/ HG2 was synthesized from three monomers, i.e., cis-butenedioic acid (cBDA), N-hydroxymethylacryalamide (NHMAm), and 2-(methacryloyloxy)ethanol (MAOE), and in situ generated 2-(3-((hydroxymethyl)amino)-3-oxopropoxy)ethyl-2-methylbutanoate (CM1) and 2-hydroxyethyl 3-(N-(hydroxymethyl)-2-methylbutanamido)-2-methylpropanoate (CM2) comonomers through microwave assisted facile polymerization in aqueous medium. Here, twenty-one GMTR-grafted-[cBDA-co-CM1-co-NHMAm-co-CM2-co-MAOE/ HG1] hydrogels were prepared by using variable amounts of synthesis parameters, of which the optimum HG2 was chosen for the scale-up repetitive As(III)-exclusion. RSM was used to measure the optimum power-temperature-time of microwave irradiation. The structures of HG1, HG2, and As(III)-adsorbed HG2/ As(III)-HG2, in situ anchored comonomers, GMTR-grafting, reusability, thermostability, and surface phenomena were comprehended by XPS, NMR, UV-vis, FTIR, TG, XRD, DLS, and SEM analyses; pH_PZC; network parameters; and thermodynamic variables. The geometries, electronic structures, and variable coordinations of As(III) with HG2 were investigated through DFT studies of HG2 and As(OH)₃-HG2. The highest exclusion efficiency of 25 mg HG2 within 5-100 mg L^-1 As(III) and at 298 K was 192.91 mg g^-1, which was significantly higher than that of HG1.

Synthesis of Well-Defined Poly(N-H Benzamide-co-N-Octyl Benzamide)s and the Study of their Blends with Nylon 6

We synthesized a series of copolybenzamides (PBA) through chain-growth condensation polymerization (CGCP) of 4-(octylamino)benzoate (M4OB) and methyl 3-(4-(octyloxy)benzylamino) benzoate (M3OOB) co-monomers. Well-defined copolybenzamides with close to theoretical molecular weights (Mn ≈ 10,000⁻13,000) and narrow molecular weight distributions (Mw/Mn < 1.40) were obtained. Selective removals of the protecting group (i.e., 4-(octyloxy)benzyl group) from the affording P(M3OOB-co-M4OB) copolybenzamides were subsequently performed to obtain P(M3NH-co-M4OB) copolymers. These novel N-H-containing copolybenzamides (named as PNHBA) can not only provide hydrogen bonds for polymer-polymer blends but also have good solubility in organic solvents. Miscibility of the PNHBA and Nylon 6 blends was investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), FT-IR, contact angle analysis, transmission electron microscope (TEM), and dynamic mechanical analysis (DMA). This study illustrates a novel type of copolybenzamide with controlled molecular weight and narrow molecular weight distribution through an effective synthetic strategy, and can be applied to a practical blend of Nylon 6 with good miscibility.

Colloidal particles in competition for stabilizer: a solvent relaxation NMR study of polymer adsorption and desorption

The competitive adsorption of poly(vinylpyrrolidone) onto silica and alumina-modified silica particles was studied using solvent relaxation nuclear magnetic resonance. The additive nature of the measured relaxation rate enabled predictions to be made of the relaxation rate in different polymer adsorption scenarios. Preferential adsorption of the poly(vinylpyrrolidone) onto the unmodified silica particles occurred when there was insufficient polymer in the system to coat the entire available surface area. Desorption was also found to occur when the polymer was initially adsorbed upon the alumina-modified particle and silica particles were added.

Polymeric drugs based on random copolymers with antimitotic activity

Polymeric drugs based on random copolymers with antimitotic activity were obtained by free radical copolymerization of oleyl 2-acetamido-2-deoxy-α-d-glucopyranoside methacrylate (OAGMA) and 2-ethyl-(2-pyrrolidone) methacrylate (EPM) at low and high conversion and analyzed in terms of microstructure, physicochemical, and biological properties. Reactivity ratios of monomers were found to be r(OAGMA) = 1.34 and r(EPM) = 0.98, indicating the obtaining of statistical copolymers with random sequence distribution of the comonomeric units in the macromolecular chains. The glass transition temperature of the copolymers presents a negative deviation from the predicted values according to the Fox equation, suggesting a higher flexibility of the alternating diad. Copolymeric systems with OAGMA contents between 10-50 mol % presented thermosensitive behavior in a heating process showing cloud point temperatures (CPT) in the range 45-28 °C with increasing OAGMA content and hysteresis in one heating-and-cooling cycle. In vitro glycolipid release studies revealed the stability of the ester group in culture medium. The polymeric drugs with 30 and 50 mol % OAGMA presented antimitotic activity on a human glioblastoma line, but they were less toxic on normal human fibroblast cultures.