Guar gum (GG) / Methylcellulose (MC) Blends and their Composites with Maghemite Nanoparticles

Miscibility of polymers decides the applicability of the resulting blends and immiscible polymer blends can be made compatible with suitable compatibilizer. Miscibility of blends of guar gum (GG) and methyl cellulose (MC) in common solvent water were studied by refractive index, density, ultrasonic velocity, and dilute solution viscometry methods at 30°C and 40°C. Based on these measurements, it is found that the polymer blend of GG/MC is immiscible. The effect of compatibilization with 0.02 wt% maghemite nanoparticle was studied in aqueous solution and found that 10/90 GG/MC blend is miscible in the presence of maghemite. Solution cast technique was used to prepare thin films of GG/MC blend – maghemite composite and characterized by scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) method.

Supramolecular Triblock Copolymers Through the Formation of Hydrogen Bonds: Synthesis, Characterization, Association Effects in Solvents of Different Polarity

Anionic polymerization techniques were employed for the synthesis of linear polystyrene (PS) and block copolymer of PS and polyisoprene (PI) PS-b-PI bearing end hydroxyl groups. Following suitable organic chemistry transformation, the –OH end groups were converted to moieties able to form complementary hydrogen bonds including 2,6-diaminopurine, Dap, thymine, Thy, and the so-called Hamilton receptor, Ham. The formation of hydrogen bonds was examined between the polymers PS-Dap and PS-b-PI-Thy, along with the polymers PS-Ham and PS-b-PI-Thy. The conditions under which supramolecular triblock copolymers are formed and the possibility to form aggregates were examined both in solution and in the solid state using a variety of techniques such as 1H-NMR spectroscopy, size exclusion chromatography (SEC), dilute solution viscometry, dynamic light scattering (DLS), thermogravimetric analysis (TGA), differential thermogravimetry (DTG), and differential scanning calorimetry (DSC).

Viscometric Study of PC / PEG blends in THF solvent and Gamma-Rays Effect on the Viscosity of PC

In this research the intermolecular interaction between polycarbonate (PC) and polyethyleneglycol (PEG) in tetrahydrofuran (THF) solvent was studied, at 25˚C using a dilute solution viscometry method (DSV). The reduced viscosity and intrinsic viscosity and viscosity interaction parameter (b) were experimentally measured, we also discuss the compatility of a polymer mixture in terms of , and the effect of gamma-rays on the reduced viscosity and intrinsic viscosity and Huggins constant of (PC). The results show that the relation between and C is liner within C=(0.9-2)g/dl, and viscometric constant KH decreases with irradiation time while increases with Tirr. http://dx.doi.org/10.25130/tjps.24.2019.055

SYNTHESIS AND NMR ANALYSIS OF THE STRUCTURE AND COMPOSITION OF TRIBLOCK POLY(ESTER-SILOXANE-ESTER) COPOLYMER BASED ON L-LACTIDE

The synthesis, structure and composition of triblock poly(ester-siloxane-ester) copolymers, PLLA-PDMS-PLLA, based on α,ω–diaminopropyl-poly(dimethyl siloxane) (PDMS) and L-lactide were studied in this work. The samples of the controlled block length were synthesized by ring-opening polymerization of L-lactide in the presence of stannous octoate, Sn(Oct)2, as a catalyst, and aminopropyl-terminated siloxane prepolymer, as a macroinitiator, in a concentrated toluene solution. Influence of temperature and concentration of the catalyst on the structure, composition and size of the copolymers were investigated by 1H and 13C NMR spectroscopy and dilute solution viscometry.

Synthesis, structure and thermogravimetric analysis of α,ω-telechelic polydimethylsiloxanes of low molecular weight

A series of ?,?-telechelic polydimethylsiloxanes (PDMS), with predetermined molecular weights of about 2500 g mol-1, was synthesized by siloxane equilibration reaction. Syntheses were performed using octamethylcyclotetrasiloxane (D4) and various disiloxanes: hexamethyldisiloxane (HMDS), 1,1,3,3-tetramethyldisiloxane (TMDS), 1,3-divinyltetramethyldisiloxane (DVTMDS), 1,3-bis(3-carboxypropyl)tetramethyldisiloxane (DCPTMDS) and 1,3-bis(3-aminopropyl)tetramethyldisiloxane (DAPTMDS). The role of the disiloxane was to introduce terminal functional groups at the end of the polymer chains and to control the molecular weight of the polymers. Polymers with trimethyl, hydrido, vinyl, carboxypropyl and aminopropyl end-groups were obtained in this way. The structure of the ?,?-telechelic PDMSs was confirmed by NMR and IR spectroscopy. The molecular weights of the polymers were determined by 1H-NMR, gel permeation chromatography (GPC) and dilute solution viscometry. Thermogravimetric analysis (TGA) under nitrogen and air showed that the type of the terminal groups significantly influenced the thermal and thermo-oxidative stability, as well as the degradation mechanism of the ?,?-telechelic PDMSs.