Poly N-vinylimidazole Research Articles

Encapsulation of bovine serum albumin within novel xanthan gum based hydrogel for protein delivery

Aim of the present study is to investigate synthesis of novel hydrogel as a potential protein carrier, intended for controlled release formulation. The hydrophilic bovine serum albumin (BSA) was chosen as a model protein to be encapsulated within xanthan gum (XG)/poly (N‑vinyl imidazole (PVI) hydrogel. Both XG/PVI hydrogel and XG/PVI/BSA matrix structures were elucidated via different analysis tools such as FTIR, XRD, FE-SEM and EDX. Both BSA loading and release profiles were determined. Cytotoxicity of XG/PVI hydrogel was investigated against normal cell line (VERO cells). The obtained results revealed that % Drug (BSA) loading (% DL) and Encapsulation Efficiency (% EE) increased with increasing both gelation time and loaded BSA concentration, while %DL and %EE decreased with increasing the polymer concentration. The maximum value of %DL and %EE was 59.50% and 99.17%, respectively. Results of in-vitro BSA release in PBS showed that increase in the polymer (XG and PVI) concentrations led to increase in BSA release. Kinetic studies of the in-vitro release of BSA from XG/PVI/BSA matrix followed non-Fickian and case II transport mechanism. Moreover, Cytotoxicity results showed good biocompatibility of this novel hydrogel. SDS-PAGE analysis confirmed that the structural integrity of BSA was not affected by the encapsulation or release conditions. Consequently, this novel hydrogel can be used as an efficient BSA carrier for protein delivery.

Catalytic properties of diblock copolymers of N-vinylcaprolactam and N-vinylimidazole

Thermoresponsive diblock copolymers of N-vinylcaprolactam (VCL) with N-vinylimidazole (NVI) have been synthesized for the first time through two-stage controlled reversible addition–fragmentation chain transfer (RAFT) polymerization. The resulting diblock copolymers exhibit the same catalytic activity toward p-nitrophenyl propionate (NPP) hydrolysis as “protein-like” copolymers of VCL and NVI. The catalytic activity of the diblock copolymers is likely caused by their structure favorable for the manifestation of catalytic properties, namely, by micelle-like chain conformations with a relatively dense core formed by the more hydrophobic PVCL block and a periphery formed by the hydrophilic poly-N-vinylimidazole (PNVI).

Corrosion Inhibition of Poly N-vinyl Imidazole for Q235 Steel in HCl Solution

Poly N-vinylimidazole (PVI) was synthesized using N-vinyl imidazole as monomer and azodiisobutyronitrile (AIBN) as initiator in a solvent of benzene. Its corrosion inhibition for Q235 carbon steel in HCl solution were investigated by means of mass loss method, Tafel polarization measurement and electrochemical impedance spectroscopy (EIS). Results indicate that inhibition efficiency of PVI can reach 90.1% in 1 mol·L -1 hydrochloride acidwith 2 mg·L -1 PVI at 298 K, and it can reach above 84% at high temperature (328 K) in solution of high acidity (2 mol·L -1 ). The elec- trochemical measurements suggest that PVI is a kind of mixed type inhibitor, the adsorption of PVI on the surface of metal obeys the Langmuir adsorption isotherm, free energies of adsorption calcu- lated indicate that PVI exhibits strong tendency of adsorption on metal via chemical adsorption.

Inhibition of the corrosion of stainless steel by poly-N-vinylimidazole and N-vinylimidazole

In this study, we investigated the inhibition of the corrosion of stainless steel (SS) in acidic solution by N-vinylimidazole monomer (NVI) and poly-N-vinylimidazole (PNVI). First, we have synthesized a polymer sample of PNVI from the monomer NVI. A stainless steel electrode was coated with this polymer as a thin film by dipping method. Corrosion rates of SS electrodes coated with PNVI films of different thicknesses were determined and compared with the results of the bare electrode in acidic solution. Corrosion rates of the bare SS electrodes were also compared with the rates in the presence of monomer and polymer, respectively, in the acidic solution. The corrosion currents were obtained by Tafel extrapolation from anodic and cathodic polarization curves. Electrochemical impedance spectroscopy (EIS) measurements were also carried out. Values of percent inhibition, wetted area and porosity were obtained for SS electrodes coated with PNVI films of different thicknesses. Experimental results show that polymer of PNVI inhibits corrosion of SS both by coating as a polymer film on electrode surface and as an inhibitor added to acidic solutions. Moreover, monomer of NVI inhibits corrosion of SS as an inhibitor added to acidic solutions and its performance seems to be better than that of PVNI.

Light scattering, viscosity and dynamic birefringence of solutions of poly-n-vinylimidazole

The molecular weights of poly-n-vinylimidazole (PVIA) have been measured by light scattering ( M w , 6·3 × 10 3 to 51 × 10 3) and the intrinsic viscosity of their solutions in a thermodynamically good solvent, namely, ethyl alcohol, have been measured. The relationship [ ν] = 2·45 × 10 −4 M w 0.69 dl/g has been established for this solvent. By extrapolating the quanity [ν]/M 1 2 to M 1 2 = 0 , the relative unperturbed dimensions of the PVIA chains have been determined: namely, ( h ̄ 0 2/M) 1 2 = 0·71 × 10 −8 cm , the length of the statistical chain segment A = 20 × 10 −8 cm and the average number of chain links in a segment s = 7·6. Flow birefringence in α-methylpyrrolidone has been measured for the unfractionated sample. The difference between the principal polarizabilities of the statistical chain segment has been determined, namely, ( α 1 − α 2) = 155 × 10 −25 cm 3. If data for the equilibrium flexibility of PVIA chains is taken into account, the optical anisotropy of the chain link becomes ( a 11 − a ⊥) = −20 × 10 −25 cm 3. It is concluded that there is almost complete freedom for the rotation of the five membered pendent ring in PVIA around the CN bond connecting this ring with the main macromolecular chain.