Graft Copolymerization Of 4-vinylpyridine Research Articles

Grafting of 4-Vinyl Pyridine onto Polyesters Initiated by Potassium Diperiodatocuprate(<i>III</i>)

In this article, the graft copolymerization of 4-vinyl pyridine onto poly (ethylene terephthalate)(PET) via the potassium diperiodacuprate(III)–PET redox system as an initiator was investigated in an alkaline medium. The graft copolymer was characterized with Fourier-transform infrared spectra analysis. A mechanism is proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, the ratio of monomer to PET, pH, and reaction temperature and time, are investigated, and the grafting conditions are optimized. Graft copolymers with high grafting efficiency are obtained, thus indicating that potassium diperiodacuprate(III)-PET redox system is an efficient initiator for this graft copolymerization. The quaternized PET-g-PVP (QPEVP) is proved to be an excellent adsorbent to heavy metal ions.

Chemically induced graft copolymerization of 4-vinyl pyridine onto carboxymethyl chitosan

A novel super absorbent polymer was prepared by graft copolymerization of 4-vinyl pyridine (4VP) onto the chains of carboxymethyl chitosan in aqueous solution using potassium persulphate (KPS) as initiator. The effect of monomer and initiator concentration, reaction temperature, and time on the grafting yield has been investigated. The maximum grafting yield was achieved at [KPS] = 4 × 10−2 mol/L, [M] = 2.5 mol/L at reaction temperature = 60 °C within reaction time = 3 h. The molecular structure of the graft copolymer was confirmed by FTIR, surface morphology before and after the polymerization was examined by SEM. Different analyses were done for the graft copolymer such as X-ray diffraction, solubility tests, and thermal analysis. Different applications were done on the graft copolymer such as swell ability in different pH solutions, dye, and metal uptake.

Functionalization of cotton fabric orienting towards antibacterial activity

The primary objective of modifying cotton fabric was to impart bactericidal properties to attract various fields such as defence, space and textile industrial applications. Chemically initiated graft copolymerization of 4-vinyl pyridine (4-VP) and acrylonitrile (AN) onto cotton fabric was carried out using ceric ammonium nitrate as a redox initiator. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of concentration of initiator [CAN], concentration of nitric acid, monomer concentration, water, temperature and reaction time. Maximum grafting of 4-VP (51.63%) and AN (69.23%) was obtained respectively at optimum \( \left[ {\text{CAN}} \right] = 2.738 \times {10^{ - 2}} \) and 2.19 × 10−2 moles/L, \( \left[ {4 - {\text{VP}}} \right] = 47.55 \times {10^{ - 22}}{\text{moles}}/{\text{L}} \), \( \left[ {\text{AN}} \right] = 18.85 \times {10^{ - 22}}{\text{moles}}/{\text{L}} \), \( \left[ {{\text{HN}}{{\text{O}}_3}} \right] = 11.9 \times {10^{ - 2}} \) and 89.5 × 10−22 moles/L in 20 and 25 ml of water at an optimum temperature 70 °C and 60 °C with in 180 and 120 min. Antibacterial properties were induced into the modified cotton fabric by treating the grafted fabric with benzyl chloride. The grafted and quaternized copolymer were characterized by FTIR and Thermogravimetrical analysis. The bactericidal action of cotton fabric was tested by filtration test and it was observed that fabric grafted with 4-VP was more effective and efficient antibacterial as compared to AN grafted cotton sample.

Grafting of 4-vinyl pyridine onto poly(vinyl alcohol) initiated by potassium diperiodatocuprate(III)

In this article, the graft copolymerization of 4-vinyl pyridine onto poly(vinyl alcohol) via the potassium diperiodatocuprate(III)-poly(vinyl alcohol) redox system as an initiator was investigated in an alkaline medium. The graft copolymer was characterized with Fourier-transform infrared spectra analysis. A mechanism is proposed to explain the generation of radicals and the initiation. The effects of reaction variables, such as the initiator concentration, the ratio of monomer to poly(vinyl alcohol), pH, and reaction temperature and time, are investigated, and the grafting conditions are optimized. Graft copolymers with high grafting efficiency are obtained, thus indicating that potassium diperiodatocuprate(III)-PVA redox system is an efficient initiator for this graft copolymerization.

REDOX INITIATED GRAFT COPOLYMERIZATION OF 4-VINYL PYRIDINE ONTO WOOL FIBER

The graft copolymerization of 4-Vinyl Pyridine (4VP) onto wool fiber in aqueous medium by peroxomonosulphate (PMS)—thioglycolic acid (TGA) redox pair in an inert atmosphere has been investigated. The effect of concentrations of 4VP, PMS, TGA on Rh, and graft parameters have been studied. In addition, the effect of time, temperature, and amount of wool fiber on Rh and graft parameters were also determined. Chemical grafting of 4VP onto wool fiber was confirmed by FTIR spectroscopy. The tensile strength of the grafts have been analyzed.

Thermal graft copolymerization of 4-vinyl pyridine on polyimide to improve adhesion to copper

The surface of poly[ N, N′-(oxydiphenylene)pyromellitimide] film, Kapton ® HN, was modified to improve its adhesion to copper metal. The polyimide surface was argon plasma activated and then exposed to air. A nitrogen-containing monomer, 4-vinyl pyridine, was then polymerized at elevated temperature under constant pressure between the argon plasma activated polyimide film and copper foil without any added photoinitiator. Optimization of the argon pretreatment time, curing temperature and curing duration resulted in almost doubling of the single lap shear strength. It is postulated that failure occurred mainly between the polyimide and the poly(4-vinyl pyridine).

Graft copolymerization of 4-vinylpyridine onto cellulose using Co (III) acetylacetonate comlex in aqueous medium

The graft copolymerization of 4-vinylpyridine (4-VP) onto cellulose has been carried out in heterogeneous conditions with cobaltacetylacetonate complex (Co (acac)3) under nitrogen atmosphere at 35±0.1°C in aqueous media. The grafting parameters such as graft yield, grafting efficiency, total conversion, frequency of grafting and rate of grafting have been evaluated as a function of concentration of 4-vinylpyridine, cobaltacetylacetonate and reaction temperature of graft copolymerization. Variation in concentration of monomer and initiator leads to a consistent increase in grafting parameters and then show a decreasing trend. The efficient grafting of monomer in presence of cobaltacetylacetonate complex is due to the coordination of the π-electrons of the 4-vinylpyridine with the metal chelate which facilitate the homolytic decomposition of metal-oxygen bond to form radicals at relatively low temperature. The rate of graft copolymerization is directly proportional to the concentration of monomer and the square root of the concentration of the cobaltacetylacetonate complex. The activation energy (ΔEa) for graft copolymeriztion has been calculated using a Arrhenius plot and is 31.0kJ mol−1 within the temperature range of 20–40°C. The grafting of 4-vinylpyridine has also been studied in presence of various additives and their effects have been suitably explained. On the basis of the experimental observations, reaction steps are proposed and rate expression has been derived.

Study of modified polypropylene nonwoven cloth. I. graft copolymerization of 4-vinylpyridine onto polypropylene nonwoven cloth by preirradiation method

Polypropylene (PP) nonwoven cloth was grafted with 4-vinylpyridine (4-VP) by a preirradiation method. The effects of preirradiation conditions on the mechanical properties of preirradiated PP nonwoven cloth and the percentage of grafting (Pg) of 4-VP onto the preirradiated PP nonwoven cloth were systematically investigated. The results indicated that the mechanical properties of preirradiated PP nonwoven cloth decreased with increasing irradiation dose and that the Pg was greatly affected by the concentration of monomer, irradiation dose, grafting reaction temperature, and the addition of inhibitor and inorganic acid in the grafting reaction system. The grafted nonwoven cloth samples were characterized using IR spectroscopy and SEM. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1861–1868, 2000

Graft copolymerization of 4-vinylpyridine and methyl acrylate onto polyethylene film by radiochemical method

Graft copolymerization of 4-vinyl pyridine (4-VP) and methyl acrylate (MA) onto polyethylene (PE) was studied in aqueous medium in air by the mutual irradiation method. The percentage of grafting was determined as a function of the (i) total dose, (ii) monomer concentration, and (iii) amount of water. The effect of different alcohols such as methanol, ethanol, isopropyl alcohol, butanol, and pentanol on the percentage of grafting of 4-VP and MA was studied. The effects of different amines on the percentage of grafting of 4-VP were also studied. The graft copolymers were characterized by IR spectroscopy and thermal analysis and by identifying the isolated polymer from the grafted film. Grafted PE film was tested for permeability behavior and was found to be permeable to a 0.5% aqueous sodium chloride solution. A plausible mechanism is suggested to explain the grafting of 4-VP and MA onto PE film. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 599–610, 1998

Swelling-assisted graft copolymerization of 4-vinyl pyridine on poly(ethylene terephthalate) films using a benzoyl peroxide initiator

Graft copolymerization of 4-vinyl pyridine (4-VP) on poly(ethylene terephthalate) (PET) films using a benzoyl peroxide (Bz2O2) initiator was investigated under different conditions including polymerization time, temperature, monomer concentration, and initiator concentration. Dimethyl sulfoxide (DMSO) was used as swelling agent to promote the incorporation and the subsequent polymerization of 4-VP to PET films. Maximum percent grafting was obtained when the polymerization was carried for a period of two hours at 65°C. Increasing the monomer concentration from 0.2M to 0.8M and Bz2O2 concentration from 1.0×10−3M to 2.5×10−3M was accompanied by a significant enhancement in percent grafting. Monomer diffusion on PET films and its effect on the grafting yield were studied and intrinsic viscosities of grafted films were also measured. © 1996 John Wiley & Sons, Inc.

Homogeneous Photoinduced Graft Copolymerization of 4-Vinyl Pyridine onto Ethyl Cellulose. 1. Influence of Biacetal and Acetonaphthone Derivatives

Abstract Homogeneous photoinduced graft copolymerization of 4-vinyl pyridine (4-VP) onto ethyl cellulose (EC) in the presence of three photosensitizers such as 1-acetonaphthone (1-An), 2-acetonaph-thone (2-An), and biacetal (Bi) in benzene solution was extensively investigated. Ultraviolet (UV) irradiation in the range 310 to 460 nm was used. The U V spectra of the mentioned photosensitizers showed n-π∗ transitions. Grafting parameters such as grafting percentage (GP) and grafting efficiency (GE) were determined as functions of the irradiation time and the concentrations of monomer, substrate, and initiator. The IR spectrum of the EC-g-4-VP copolymer shows the appearance of new peaks between 1600 and 1690 cm-1 indicating the presence of poly-4-vinyl pyridine (p-4-VP) grafted chains. The rate of copolymerization of 4-VP onto EC in the presence of 1-An, 2-An, and Bi was determined as 0.98% min-1, 0.88% min-1 and 0.042% min-1, respectively. A good correlation was observed between the change in absorbance at ...

Graft Copolymerization of 4-Vinylpyridine Onto Modified Cellulosic Fibers. the Ceric Ion Concentration Effect

Abstract The graft copolymerization of 4-vinylpyridine was carried out on mercerized cellulose and partially carboxymethylated cellulose (PCMC) using eerie ammonium nitrate (CAN) as the initiator. the grafting parameters (grafting efficiency (GE), graft yield (G), and total conversion (C1)) were studied as a function of CAN concentration. It was shown that by increasing the CAN concentration, G and C, reached a maximum. the graft yields for PCMC were significantly higher than those for mercerized cellulose. the largest GE values appeared for PCMC and mercerized cellulose at low and high CAN concentrations, respectively. the Ce(IV) consumption during grafting increased with rising concentration of CAN, and it was greater in the case of PCMC than of mercerized cellulose. After acid hydrolysis of the polysaccharide backbone, the average molecular weight of grafts was determined viscometrically. Molecular weight decreased with initiator concentration. Graft frequency (GF), on the other hand, increased with CAN concentration. GF for PCMC was higher than that for mercerized cellulose. Ce(IV) consumption increased with CAN concentration and it was lower for mercerized cellulose than that consumed during grafting on PCMC. After that, the effect of CAN concentration on the graft copolymerization onto PCMC was examined while the total nitrate ion concentration was maintained constant at 1.59 M by addition of sodium nitrate. Maximum G, C1 and Ce(IV) consumption were higher than in the previous case.

Graft Copolymerization of 4-Vinylpyridine Onto Partially Carboxymethylated Cellulose. the Degree of Substitution Effect

Abstract The graft copolymerization of 4-vinylpyridine (4-VP) onto partially car-boxymethylated cotton (PCMC), having different carboxymethyl contents, was investigated. Under similar reaction conditions, both the graft yield and eerie ion consumption increased by increasing the degree of substitution of carboxymethyl groups of PCMC up to a value of 0.11, beyond which grafting and Ce(IV) consumption decreased. Proof for grafting onto PCMC was provided through IR analysis. the eerie salt-initiated polymerization of 4-VP in the absence of PCMC was also studied. Three series of homo-polymerization reactions of 4-VP directly initiated by eerie ammonium nitrate were carried out with varying reaction times. Each series was run at a different nitric acid concentration. Both conversion and eerie ion consumption, as well as molecular weight, increased with reaction time. Increasing the nitric acid concentration increased both conversion and eerie ion consumption while the molecular weight decreased.

Graft copolymerization of 4-vinylpyridine onto cellulosics. effect of temperature

Graft copolymerization of 4-vinylpyridine (4-VP) was carried out on unmodified cotton and partially carboxymethylated cotton (PCMC), using ceric ammonium nitrate as initiator. The grafting parameters were studied as a function of temperature and amount of cellulose. With unmodified cotton, the graft yield increased up to 40° and then decreased on increasing temperature. Graft yields for PCMC increased with increasing temperature and reached a constant value beyond 30°. Carboxymethyl groups attached to cellulose enhanced both graft yield and grafting efficiency as well as the ceric ion consumption. The molecular weight of grafted poly(4-VP) was obtained viscometrically after hydrolysing away the cellulose backbone, and it was found to decrease while the graft frequency increased with temperature. The activation energies were found to be 32.6 and 8.7 kJ/mol for PCMC and unmodified cotton respectively. The weight increase of cellulose due to grafting increased with increasing content of cellulose in the reaction mixture. The presence of occluded air in the grafting system caused a decrease in graft yield.

Preparation of charge-mosaic membranes by radiation-induced graft copolymerization of PE films with styrene and 4-vinylpyridine: II. Effects of pre-irradiation dosage, atmosphere, storage time and storage temperature of grafting of 4-vinylpyridine onto PE films

The graft copolymerization of 4-vinylpyridine onto LDPE films pre-irradiated with a 1.2 MeV electron beam, was carried out in the vapor phase as the second step in the preparation of charge-mosaic membranes. The effects of pre-irradiation dosage, atmosphere, storage time and storage temperature of PE films on the grafting process were studied by measuring the rate of free radical decay under different conditions. The results of ESR study show that: (1) The free radicals, created in the course of pre-irradiation, decrease stepwise with different decay constants. At first, they decay rapidly, but afterwards they decay more and more slowly. (2) At different temperatures, free radicals have different decay constants but they have almost the same decay characteristics as described above. (3) Sampling pre-irradiated PE films during the fast decay period may cause a pronounced error in the percentage graft, so that the standard deviation is much larger. On the other hand, sampling pre-irradiated PE films during the slow decay period greatly improves the precision of the percentage graft, so the standard deviation is much smaller. (4) For the above reason, the optimum storage time of pre-irradiated PE films at 5°C may be considered to be in the range of 48–120 h after the free radicals have been created. The results of graft copolymerization of pre-irradiated PE films with 4-vinylpyridine in the gaseous phase at different temperatures showed that: (1) At higher grafting temperatures, the grafting rate of 4-vinylpyridine onto PE films is much higher than the swelling rate of PE films by monomer vapor. As the grafted macromolecular chains propagated surround the activated sites very quickly, there is a local thickening effect, and the resulting graft copolymer looks rough. (2) At lower grafting temperatures, the grafting rate of 4-vinylpyridine seems to be comparable with the swelling rate of PE films by monomer vapor; an even and smooth copolymeric film can be obtained.

The radiation-induced graft copolymerization of 4-vinyl pyridine to terylene.

The method and mechanism of radioinduced graft copolymerization of 4- vinyl pyridine to Terylene filament yarn fabric, polyacrylonitrile, and polyethylene are described. The best results are obtained when the dry fabric is irradiated in air and is followed by reacting 4-vinyl pyridine with the fabric in the absence of oxygen. The 4-vinyl pyridine is applied to the fabric as a 2% aqueous solution. Graphs are given showing the effect of temperature on the rate of grafting of 4-vinyl pyridine to Terylene at a dose of 1.5 Mrad and the effect of dose rate on grafting. Results show that dyeability and antistatic finish are improved by the irradiation process. (N.W.R.)