Graft copolymerization of acrylonitrile onto acetylated jute fibers

Graft copolymerization of acrylonitrile (AN) onto acetylated chemically modified jute was carried out in the temperature range 40–60°C using V⁵⁺-cyclohexanone redox initiator system. The effects of temperature, time, concentrations of metal ion (V⁵⁺), monomer (AN), cyclohexanone, some inorganic salts, and organic solvents on percent grafting have been studied. IR spectra of acetylated chemically modified jute and grafted jute have been taken, and their characteristic bands have been identified. Grafting has improved the thermal stability and also the lightfastness rating of jute fibers dyed with basic dyes.     

Graft copolymerization of methyl methacrylate onto jute fibers. Studies on vanadium (V)-cyclohexanol redox system

Graft copolymerization of methyl methacrylate (MMA) onto natural jute (chemically modified) was studied using V⁵⁺ -cyclohexanol redox initiator system. The effects of time, concentration of metal ion (V⁵⁺), monomer (MMA), substrate, amount of jute fibers, temperature, and acid concentration on graft yield have been studied. The effects of some organic solvents and inorganic salts on graft yield have also been studied. A grafting mechanism is proposed and an expression has been derived for the reaction rate. Grafting has improved the thermal stability and the light fastness of jute fibers dyed with basic dyes. IR spectra of the natural jute (chemically modified) and grafted jute have been taken. More than 170% graft yield could be achieved with the present system.     

Ce(IV)-N-acetylglycine initiated graft copolymerization of acrylonitrile onto chemically modified pineapple leaf fibers

Graft copolymerization of acrylonitrile (AN) onto chemically modified pineapple leaf fiber (PALF) was studied using Ce(IV) and N-acetylglycine (NAG) combination as initiator in the temperature range 40–60°C. The effects of concentration of monomer, Ce(IV), and NAG on graft yield have been studied. Besides the effects of time, temperature, acid, amount of PALF, some inorganic salts and organic solvents on graft yield have been investigated. FTIR and scanning electron microscopy of PALF and grafted PALF have been studied. Grafting has improved the thermal stability of PALF. © 1996 John Wiley & Sons, Inc.     

Graft copolymerization of methyl methacrylate onto jute fiber initiated by cerium(IV)–DMSO redox initiator system

The kinetics of graft copolymerization of methyl methacrylate (MMA) onto chemically modified jute fibers initiated by the Ce(IV)–DMSO redox system was studied in the temperature range of 40–60°C. By studying the effects of the concentration of the monomer, Ce(IV), and DMSO on the rate of grafting, the optimum conditions for grafting were determined. Also, the effect of temperature, time, concentration of the acid, the amount of jute fiber, and some inorganic salts and organic solvents on the rate was investigated. A kinetic scheme was proposed on the basis of the experimental findings. Infrared spectra of chemically modified jute and grafted jute was investigated. More than 120% of grafting could be achieved with the present system. The characterization of MMA-grafted chemically modified jute by TGA and DTA studies was made. The thermal stability of the jute fibers was improved by grafting. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2569–2576, 1998     

Graft copolymerization of styrene,methylmethacrylate, and acrylonitrile onto jute fibres

The contribution of jute constituents, namely, water soluble matters, waxes, pectins, lignin, hemicelluloses, and α-cellulose in the graft copolymerization reaction of jute fabric with some vinyl monomers was investigated. Styrene, methylmethacrylate, and acrylonitrile were used as the monomers and Fe²⁺/H₂O₂ redox system as initiator. The graft copolymerization reaction was carried out at 80°C using different concentrations of monomer and initiator for different lengths of time. The water soluble matters, pectins, and lignin were found to accelerate the graft copolymerization reaction during the initial stages of the reaction and in the meantime impede termination during the latter stages of the reaction. Generally, the magnitude of grafting is governed by nature of the substrate, nature of the monomer, and the conditions of the polymerization reaction. Grafting decreases the moisture regain of jute and substrates derived thereof irrespective of the monomer used within the range studied. Also, grafting decreases the tensile strength and imparts rot-proofing properties to the substrates examined.     

Graft copolymerization of methyl methacrylate onto biomedical polyvinyl chloride initiated by Ce(IV)–glucose redox system

Graft copolymerization of methyl methacrylate onto PVC was carried out using Ce(IV)–glucose redox system in aqueous sulfuric acid medium under nitrogen atmosphere. To find out the optimum conditions for grafting, effects of concentrations of metal ion, glucose, monomer, and acid on the percentage of grafting was studied. The graft yield was found to be influenced by reaction time, temperature, and amount of PVC. An appreciably high graft yield could be achieved with the present system. On the basis of the results from the present study, a plausible reaction mechanism has been proposed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2105–2111, 2005     

Grafting vinyl monomers onto silk fibers IV. Graft copolymerization of methyl methacrylate onto silk using bromate-thiourea redox system

The use of a bromate-thiourea redox system to initiate graft copolymerization of methyl methacrylate onto silk has been investigated. The rate of grafting has been determined by varying the concentration of bromate ion, monomer, thiourea, the temperature and the solvent. The graft yield increases with increasing the bromate ion concentration up to 20 mmo1/1. With further increase of oxidant the graft yield decreases. The percentage of grafting increases with increase of hydrochloric acid up to 40 mmo1/1. Thereafter it decreases. The effect of increasing thiourea concentration up to 15 mmo1/1. is to bring about an increase in the graft yield. Above this concentration grafting decreases sharply. The rate of grafting increases with increase of temperature. The use of various water soluble solvents effects the percentage of grafting considerably. The alkali solubility of the grafted fiber has been investigated.     

Graft copolymerization of acrylonitrile onto cotton cellulose by potassium permanganate–thioacetamide redox system

The graft copolymerization of acrylonitrile onto cotton, initiated by the KMnO₄–thioacet-amide redox system in an aqueous medium, has been investigated. The percentage graft yield was determined by varying the concentrations of KMnO₄, acrylonitrile, thioacetamide, and temperature. The percentage graft yield increased initially and then decreased with increasing concentrations of KMnO₄ and thioacetamide, with an optimum yield not greater than 21%. The percentage graft yield, however, was greatly enhanced with a value of up to 66% as the concentration of acrylonitrile was increased. The percentage graft yield increased with temperature in the range of 35–70°C with a calculated activation energy of 8.33 Kcal/mol. The effects of solvents and amines on the percentage graft yield were also investigated. © 1994 John Wiley & Sons, Inc.     

Graft copolymerization onto Tamarind Kernel Powder: Ceric(IV)‐initiated graft copolymerization of acrylonitrile

Tamarind Kernel Powder (TKP) is derived from the seeds of Tamarindus indica Linn., a common and most important tree of India. It is extensively used in cotton sizing, as a wet‐end additive in the paper industry, as a thickening, stabilizing, and gelling agent in the food industry. However, because of its fast biodegradability there is a need to prepare graft copolymers of TKP. The graft copolymerization of acrylonitrile (AN) onto TKP with ceric ammonium nitrate as a redox initiator in an aqueous medium has been studied. The reaction conditions were optimized to afford maximum percent grafting and percentage grafting efficiency of AN onto TKP, which was found to be 86% and 64%, respectively. Fourier Transform Infrared Spectrum of the grafted products showed an additional sharp absorption band at 2244 cm^?1 due to ? C?N stretching, thereby confirming the grafting of AN onto TKP. Scanning electron microscopy studies indicated change in contour of the polysaccharide on grafting and the thick polymeric coating of AN on the surface alongwith grafting of AN such that all the gap between polysaccharide particles have been closed. Thermal studies using thermogravimetric and differential gravimetric analyses confirmed that TKP‐g‐AN has overall high thermal stability than pure TKP. Reaction mechanism of grafting of acrylnitrile onto TKP is also proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Aqueous polymerization of acrylonitrile by Ce(IV)-diacetone alcohol redox system

The kinetics of oxidation of DAA by Ce(IV) in dilute sulphuric acid medium has been studied and the reaction was found to obey a second order rate law. This DAA — Ce(IV) redox system has been used for the polymerization of acrylonitrile and the rate of polymerization was found to be proportional to[Ce(IV)]^0.5, [DAA]^0.5 and [M]^1.5. Based on these results a probable mechanism for initiation and termination has been proposed. The chain lengths of the polymers were found to increase with [M] and decrease with both [Ce(IV)] and [DAA].     

Graft copolymerization of methyl methacrylate onto starch using a Ce(IV)–glucose initiator system

Graft copolymerization of methyl methacrylate onto starch was carried out in aqueous medium using Ce(IV)–glucose initiator in the temperature range 40–60°C. Effects of concentration of Ce(IV), glucose, H₂SO₄, monomer, and starch on grafting were investigated. Percentages of grafting were evaluated and compared. The overall energy of activation was calculated from the effects of time and temperature of polymerization. The reaction mechanism was also discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 981–990, 2004     

Graft copolymerization of styrene and acrylonitrile onto EPDM

Acrylonitrile–EPDM–styrene (AES) graft copolymers were synthesized by solution graft polymerization of styrene (St) and acrylonitrile (AN) onto EPDM in an n‐hexane/benzene solvent with benzoyl peroxide (BPO) as an initiator. The structure changes were studied by an FTIR spectrophotometer. The grafting parameters were calculated gravimetrically. The influence of the polymerization conditions, such as the reaction time, concentration of the initiator, EPDM content, and weight ratio of St/AN, on the structure of the products was investigated. It was found that a proper initiator concentration and EPDM content will give a high grafting ratio of the AES resin. The thermal property of the copolymer was studied using programmed thermogravimetric analysis (TGA). The results showed that the copolymer has a better heat‐resistant property than that of ABS, especially for the initial decomposition temperature (T_in) and the maximum weight loss rate temperature (T_max). Also, the mechanism of the graft reaction was discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 428–432, 2002     

三元乙丙橡胶溶液接枝丙烯腈

对三元乙丙橡胶在二甲苯中与丙烯腈的接枝共聚进行了研究,结果表明AIBN可以有效引发接枝共聚,并且正交实验发现单体用量、引发剂浓度和反应温度均对接枝率有重要影响,条件适当接枝率可达15％以上。实验证明,接枝共聚物对丁腈橡胶／三元乙丙橡胶并用具有明显的增容作用。     

丙烯腈-三元乙丙橡胶-苯乙烯接枝共聚物AES的合成

用溶液聚合法合成了丙烯腈-三元乙丙橡胶-苯乙烯接枝共聚物（AES）,研究了接枝聚合反应的影响因素,并进行了红外光谱表征。结果表明,三元乙丙橡胶（EPDM）已接枝上丙烯腈（AN）和苯乙烯（St）的共聚物（SAN）支链,即EPDM与AN及St发生了接枝共聚合反应。     

Graft copolymerization of acrylic acid onto caesarweed fibers by cerric ion–toluene redox pair

The graft copolymerization of acrylic acid onto caesarweed fibers in aqueous media by cerric ion–toluene redox pair has been investigated. The percentage graft increased and then decreased with cerric ion concentration ranging from 8.3 to 100.0 × 10^?3 M with a peak value of 17%. The effects of toluene, substituted toluenes, acids, and acrylic acid were examined. The percentage graft increased and then decreased with toluene concentration with an optimum value of 53% at 18.0 × 10^?4 M toluene. Under identical reaction conditions, the percentage graft after 30 min for the graft polymerization initiated by substituted toluenes are in the order of p-toluene sulfonic acid > toluene > p-Xylene ? o-toluidine. Low concentrations of acetic acid were favorable to the graft polymerization. The percentage graft increased linearly with acrylic acid concentration reaching a value of 53% at 1.39 M acrylic acid. The presence of neutral salts had nominal effects on the percentage graft. The effect of temperature was investigated between 20 and 60°C. The percentage graft increased with temperature up to 40°C but showed a negative temperature dependence beyond 40°C. The calculated activation energy was 6.2 kcal mol^?1. Characterization of the physical properties of the grafted fibers was also conducted. © 1994 John Wiley & Sons, Inc.     

Graft copolymerization of methacrylates onto wool fibers

Grafting of butyl (BuMA), decyl (DeMA), and octadecyl methacrylate (ODeMA) onto reduced wool was carried out by using K₂S₂O₈ or K₂S₂O₈–LiBr redox system as initiator. The influence of the monomer and monomer concentration, temperature, and duration of the reaction on the percentage of grafting was studied. Evidence of grafting was provided by scanning electron microscopy, size exclusion chromatography, and infrared spectroscopy.     

Graft copolymerization of acrylonitrile onto bagasse and wood pulps

Graft copolymerization of acrylonitrile onto bagasse and wood pulps has been studied using ceric ammonium nitrate as initiator. The effect of order of reactants addition on grafting was examined: three methods were studied. Addition of the pulp to a mixture of initiator and monomer (method A) resulted in more efficient grafting than the other two methods. The reaction produced more grafting at 50°C than at 30°C or at 40°C. The results showed that the monomer and initiator concentrations are the major factors influencing the grafting rate of acrylonitrile. Increasing the acrylonitrile or initiator concentration was accompanied by a substantial increase in graft yields. Increasing the initiator concentration is more effective on polymerization rate than the increase in monomer concentration. The extent of grafting of this monomer can best be controlled by reaction time. Water swelling of pulps significantly affected the grafting rate of acrylonitrile as well as the ceric consumption during grafting. The reactivity of bagasse pulp towards grafting of acrylonitrile is higher than that of wood pulp due to a more open structure of cellulose in bagasse pulp as well as the presence of some lignin which accelerates grafting. Ceric consumption during grafting depends on the nature of the pulp as well as the monomer and initiator concentrations, time, temperature, and the method of grafting. More Ce(IV) is consumed during grafting than during oxidation of the pulps under identical reaction conditions, due to homopolymer formation which accompanied grafting. The ceric consumption by bagasse during grafting or oxidation is somewhat greater than that consumed by wood pulp under similar reaction conditions.