Graft Copolymerization Of N-vinylpyrrolidone Research Articles

Grafting of N-vinyl-2-pyrrolidone onto κ-carrageenan for silver nanoparticles synthesis

A water soluble, non-gel, poly (N-vinyl-2-pyrrolidone)/κ-carrageenan (PVP/KC) hybrid was synthesized by graft copolymerization of N-vinylpyrrolidone (VP) onto κ-carrageenan in an aqueous medium using ammonium persulphate (APS) as an initiator. Factors affecting the polymerization reaction such as ammonium persulfate concentration, reaction temperature and time, liquor to KC ratio (LR) and KC to VP molar ratio were studied. The results obtained revealed that the optimum reaction polymerization conditions to prepare that hybrid with a total conversion of 93.9% are: [VP], 0.1799 mol/L; VP/KC molar ratio, 50%; [APS], 0.0105 mol/l; LR, 15 l/k; reaction temperature, 90 °C and reaction time, 75 min. Moreover, the grafted KC of that hybrid was characterized via investigating its FTIR analysis. Furthermore, the potential application of such hybrid as a route for synthesis of silver nanoparticles (Ag NPs) using AgNO3 as a precursor was investigated. The synthesized Ag NPs are characterized using the ultraviolet-visible spectroscopy (UV–vis) as well as transmission electron microscope (TEM). The UV–vis showed a band at 435 nm that confirms the presence of Ag NPs. The TEM image shows that such nanoparticles have a spherical structure with an average size ranging from 3 −18 nm.

Graft copolymerization of N -vinylpyrrolidone onto stearyl alcohol to impart water repellency and antibacterial properties for cotton/polyester fabric

Abstract A PVP/SA adduct was prepared by reacting of N-vinylpyrrolidone with stearyl alcohol in presence of ammonium persulphate as initiator in different preparation reaction conditions. The optimum conditions to prepare that adduct are VP/SA, 25%; LR, 1 l/kg; reaction temperature, 80 °C and reaction time, 40 min. The graft copolymerization of N-vinylpyrrolidone onto stearyl alcohol was confirmed by the FTIR analysis. The TEM image of the prepared adduct emulsion shows that its particle size ranges from 45 to 173 nm. Finishing of cotton/polyester fabric sample with easy care finishing bath containing 80 g/l of that adduct emulsion results in an increasing in the tensile strength, water repellency rating, antibacterial properties, softness degree, and stiffness along with a reduction in the resiliency of treated fabric. The surface of the prepared adduct treated fabric was characterized via scanning electron microscope.

Protein adsorption of radiation functionalized LDPE sheets

Low density polyethylene (LDPE) sheets were modified by radiation-induced graft copolymerization of N-vinyl pyrrolidone (NVP) and acrylonitrile (AN) binary comonomer of different molar ratios. The factors affecting the radiation modification process were optimized. The radiation-modified LDPE sheets were further modified via the chemical treatment of the grafted nitrile groups with thiourea. The modification processes were confirmed by FTIR and the modified LDPE sheets were characterized by studying their swelling behavior. The protein adsorption ability of the modified LDPE sheets was examined towards creatinine, as protein derivative and γ-globulin fraction (II). Adsorption kinetics were calculated and possibility of selective adsorption was evaluated.

Preparation of gelatin-N-vinylpyrrolidone graft copolymer

The graft copolymerization of N-vinylpyrrolidone (VP) onto gelatin was carried out by the following four different initiator systems: AIBN, K 2 S 2 O 8, H 2 O 2 -Fe 2+ , and Ce 4+ - HN0 3 . The last one caused the monomer to lose the double-bond and polymerization ability due to the hydrolysis of the monomer. Using α,α-azobisisobutyronitrile as an initiator, the graft copolymerization of gelatin and N-vinylpyrrolidone in aqueous medium was studied systematically. The relationships between the rate of grafting and the concentration of initiator, monomer, and gelatin were established experimentally. Meanwhile, the rate equation was also derived from the proposed reaction mechanism, and it was similar to the equation previously obtained experimentally. The apparent activation energies for homopolymerization (E h ), graft copolymerization (E g ), and over all polymerization (E p ) were calculated. The graft efficiency and molecular weight of the grafted PVP were measured by hydrolyzing the backbone with hydrochloric acid. The graft copolymers Gel-g-PVP were added into the coating films, and the physical properties of the films, such as hardening ability, dimensional stability, and wetting property were investigated.

Preparation of gelatin–N‐vinylpyrrolidone graft copolymer

The graft copolymerization of N-vinylpyrrolidone (VP) onto gelatin was carried out by the following four different initiator systems: AIBN, K2S2O8, H2O2—Fe2+, and Ce4+—HNO3. The last one caused the monomer to lose the double-bond and polymerization ability due to the hydrolysis of the monomer. Using α,α-azobisisobutyronitrile as an initiator, the graft copolymerization of gelatin and N-vinylpyrrolidone in aqueous medium was studied systematically. The relationships between the rate of grafting and the concentration of initiator, monomer, and gelatin were established experimentally. Meanwhile, the rate equation was also derived from the proposed reaction mechanism, and it was similar to the equation previously obtained experimentally. The apparent activation energies for homopolymerization (Eh), graft copolymerization (Eg), and over all polymerization (Ep) were calculated. The graft efficiency and molecular weight of the grafted PVP were measured by hydrolyzing the backbone with hydrochloric acid. The graft copolymers Gel-g-PVP were added into the coating films, and the physical properties of the films, such as hardening ability, dimensional stability, and wetting property were investigated. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1485–1492, 1998

Gamma ray induced graft copolymerization ofN-vinylpyrrolidone, acrylamide and their mixtures onto polypropylene films

The radiation initiated grafting of N-vinylpyrrolidone (NVP) acryl-amide (AAm) and their mixtures onto polypropylene (PP) films using a direct radiation technique has been investigated. Different solvents were used for diluting the monomers and it was found that dioxane was suitable for this grafting system. The influence of other grafting parameters such as inhibitor, monomer concentration and dose rate on the rate of grafting and grafting yield was studied. The values of the coefficients relating the grafting rate to monomer concentration and dose rate were found to be 1·4 and 1·5 for (NVP), and 1·6 and 1·47 for (AAm), respectively. Also, the coefficients relating grafting rate to co-monomer concentration for 20/80 and 50/50 AAm/NVP mixtures were found to be 1·6 and 1·7. Some physicochemical properties such as swelling, thermal behaviour, mechanical and electrical conductivity were also investigated, and the possibility of some practical uses, e.g. the removal of heavy metals from solution, for the grafted membranes is discussed. © 1998 SCI.