Aspects of thermal grafting of acrylonitrile onto ethyl cellulose in homogeneous media

Abdel-Razik, E.A.

doi:10.1002/actp.1995.010460206

Cited by 5 publications

(6 citation statements)

References 14 publications

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“…Furthermore, the increase in VCMP content facilitates the formation of PS macroradicals, which in turn decrease the GE. Similar observations have previously been reported for some copolymers 21–24…”

Section: Resultssupporting

confidence: 92%

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Modification of polystyrene properties through grafting with N‐vinylcarboxamido‐2‐methylpropane sulfonic acid monomer

Aggour

2004

Polymer International

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Polystyrene (PS) possesses good mechanical properties, but its surface is relatively inert and hydrophobic. Grafting of N‐vinylcarboxamido‐2‐methylpropane sulfonic acid (VCMP) is useful to hydrophilize the PS surface. Grafting was performed using benzoyl peroxide (BPO) as an initiator in toluene:methanol solvent mixture (3:1 volume ratio). The influence of the main factors on grafting, such as temperature, time, concentrations of initiator, PS and VCMP, has been studied. The results show that the initial rate of polymerization and percentage of grafting are enhanced by increased temperature. Furthermore, the specific rate constants of the first order reaction/are determined, and the activation energy of the grafting reaction is estimated. The grafting parameters are established and a suitable mechanism of the reaction is proposed. The grafted PS is to characterized through infrared spectra, intrinsic viscosity, thermogravimetric analysis (TGA) and differential gravimetric analysis (DTG). The kinetics of thermal degradation and the order of the thermal stabilities are given. Also the decomposition activation energies of the thermal degradation are determined, and confirm the thermal stabilities of the polymers used. © 2004 Society of Chemical Industry

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Section: Resultssupporting

confidence: 92%

“…An increase in monomer concentration would be expected to increase both the degree of grafting and the molecular weight of graft copolymer 21. 22 Accordingly the results in Fig 2 shows that as the VCMP concentration increased from 0.005 to 0.04 g ml −1 .…”

Section: Resultsmentioning

confidence: 90%

Modification of polystyrene properties through grafting with N‐vinylcarboxamido‐2‐methylpropane sulfonic acid monomer

Aggour

2004

Polymer International

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“…The results given in Table I show that the grafting yields were increased by raising the temperature. In aqueous medium the increase in temperature caused a high rate of dissociation of persulfate ions to sulfate radical ions 14–17. The sulfate radical ions formed reacted with water to produce hydroxyl radicals as follows:…”

Section: Resultssupporting

confidence: 89%

“…Furthermore the increase in AMPS content facilitates the formation of PVA macroradicals, which in turn decrease the GE %. A similar trend has been found in various copolymerization systems 17. 21, 22…”

Section: Resultssupporting

confidence: 87%

“…The increase in monomer concentration would be expected to increase both the percentage of grafting and the molecular weight of grafting copolymer 17. 21 Accordingly the results in Fig 1 indicate that, as the monomer concentration (AMPS) is increased from 0.0272 to 0.075 g ml −1 , there is an increase in both GP % and WC %, while GE % decreases.…”

Section: Resultsmentioning

confidence: 91%

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Reaction kinetics of graft copolymerization and thermochemical studies of the degradation of poly(vinyl alcohol) graft copolymer

Aggour

2001

Polymer International

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Poly(vinyl alcohol) (PVA) is a water‐soluble and biomedical polymer. 2‐Acrylamido‐2‐methyl‐1‐propanesulfonic acid was grafted onto PVA using ammonium persulfate as radical initiator. The influences of synthesis conditions such as temperature, concentrations of initiator, PVA and monomer were investigated. Both the initial rate of grafting and the final percentage of grafting were increased by an increase in reaction temperature. The reaction kinetics were studied to determine the rate constants of the first‐order reactions. An activation energy of 16.3 kJ mol−1 was found for the grafting reaction. The graft copolymers were characterized by IR and intrinsic viscosity measurements. A proposed mechanism of the grafting reaction is discussed. Kinetics of the thermal degradation were studied using a thermogravimetric method and the order of thermal stabilities are given. The apparent activation thermodynamic parameters, Ea, ΔH*, ΔS* and ΔG* were determined and correlated to the thermal stabilities of the homo‐ and grafted polymers. © 2001 Society of Chemical Industry

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Polymer‐based metal adsorbents via graft copolymerization of polyvinyl alcohol with diaminomaleonitrile: A green chemistry approach

Abdel-Razik

Abbo

Almahy

2012

J of Applied Polymer Sci

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Synthesis, characterization, and amidoximation of diaminomaleonitrile‐functionalized polyvinyl alcohol (PVA) grafts were studied. Ceric ammonium nitrate (CAN) was used as an initiator in an aqueous nitric acid medium under N2 atmosphere. Optimum conditions for grafting were as follows: monomer concentration [DAMN] = 1.4M, [CAN] = 16 × 10−2 mol/L, T = 50°C, and t = 2 h. Water uptake of the PVA graft films increased with the increase of grafting yield. The imparted cyano group of the grafted PVA polymer chains (with degree of grafting up to 136%) was converted into amidoxime group by the reaction with hydroxylamine hydrochloride. The grafted polymers were characterized by FTIR spectroscopy, differential scanning calorimetry, and thermal gravimetric analysis. The grafted PVA films are more thermally stable than the ungrafted PVA membrane, because the grafted membrane showed a single degradation pattern despite having two components. A decrease in Tg values is observed as the grafting yield of copolymers increases indicating the incorporation of polydiaminomaleonitrile chains in amorphous copolymers with higher thermal stability. The prepared amidoximated DAMN136‐g‐PVA was investigated for its properties in removing heavy toxic metals, such as Pb2+, Cd2+, Zn2+, Fe3+, Cu2+, Ni2+, and Co2+ from water. The amidoximated film is characterized by a considerably greater binding ability with respect to heavy metals. The nature of the metal ion also has great importance in the amount binding to the polymeric material. The kinetics of the sorption/desorption process for Co2+, Ni2+, and Zn2+ were investigated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

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Aspects of thermal grafting of acrylonitrile onto ethyl cellulose in homogeneous media

Cited by 5 publications

References 14 publications

Modification of polystyrene properties through grafting with N‐vinylcarboxamido‐2‐methylpropane sulfonic acid monomer

Modification of polystyrene properties through grafting with N‐vinylcarboxamido‐2‐methylpropane sulfonic acid monomer

Reaction kinetics of graft copolymerization and thermochemical studies of the degradation of poly(vinyl alcohol) graft copolymer

Polymer‐based metal adsorbents via graft copolymerization of polyvinyl alcohol with diaminomaleonitrile: A green chemistry approach

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