Radiation-induced graft copolymerization of 2-hydroxyethyl methacrylate onto chloroprene rubber membrane. II. Characterization of grafting copolymer

The cobalt-60 radiation-induced graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto a chloroprene rubber (CR) membrane has been studied in ethanol. The structure, morphology, crystallinity, thermal stability, and hydrophility of graft copolymer were characterized by means of Fourier transform infrared photoacoustic spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, differential thermal gravimetric analysis, and contact angle test methods, respectively. The permeabilities of urea, creatinine, and creatine through the CR and CR-g-HEMA membranes are investigated in a dialysis cell, and the permeation mechanism is also discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1745–1750, 1998     

Studies on graft copolymerization of 2-hydroxyethyl methacrylate onto poly(vinyl chloride)

Poly(vinyl chloride) was dehydrochlorinated in alkali solution and then grafted with 2-hydroxyethyl methacrylate (HEMA) using benzoyl peroxide as a free-radical initiator under a nitrogen atmosphere. The investigations involved examining the effects of grafting efficiency on various conditions, such as degree of dehydrochlorination, HEMA concentration, solvent effect, and reaction time. Maximum grafting to the extent of 57.2% was obtained. The mixed solvent grafting was attempted. © 1994 John Wiley & Sons, Inc.     

Grafting of β-cyclodextrin-modified 2-hydroxyethyl methacrylate onto polyurethane

2-Hydroxyethyl methacrylate (HEMA) and β-cyclodextrin are bridged using toluene-2,4-diisocyanate (TDI) by reacting the  OH group of HEMA and one of the primary  OH groups of β-cyclodextrin. The modified HEMA is grafted to polyurethane by γ-irradiation. The preliminary study showed that the membrane potential of conventional polymers like polyurethane could be enhanced considerably by this type of modification. © 1996 John Wiley & Sons, Inc.     

Preparation and permeability of a block copolymer dialysis membrane by poly(γ-methyl-L-glutamate) and poly(ethylene glycol)

The block copolymer (PMLG-b-PEG) of poly(γ-methyl-L -glutamate) (PMLG) and isocyanate-terminated poly(ethylene glycol) was synthesized. Membranes were prepared by casting 2% 1,2-dichloroethane solutions of the polymer onto a glass plate and by evaporating the solvent at room temperature. The structure and microdomain morphologies of the membranes were observed with IR spectroscopy and scanning electron microscopy, respectively. Measurement of the contact angles of deionized water on polymer membrane surfaces was made. The mechanical properties of the membranes were also determined. The permeability of the PMLG-b-PEG and PMLG membranes toward urea and creatinine was studied in a dialyzer. In all cases, the block membranes showed improved permeability toward those solutes in comparison with the PMLG membranes. The permeation coefficients of urea, through the PMLG-b-PEG300 and PMLG-b-PEG1000 membranes, were about 2.3 and 3.2 times larger than that of PMLG membranes, and for creatinine through PMLG-b-PEG300 and PMLG-b-PEG1000 membranes, were about 1.0 and 2.0 times larger than that of PMLG membranes. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:75–82, 1998     

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     

Gamma‐radiation‐induced graft copolymerization of acrylamide onto crosslinked poly(N‐vinylpyrrolidone)

Crosslinked poly(N‐vinylpyrrolidone) (PVPy) beads were irradiated with γ‐rays in air from a ⁶⁰Co source. Preirradiated beads were grafted with polyacrylamide by refluxing with acrylamide in water or dioxane. Conditions for optimum grafting were determined under a variety of reaction parameters, such as the total dose, duration, and temperature of heating, and the molar concentration of acrylamide used. The effect of the addition of methanol to the aqueous medium during grafting was also studied. The pendant carboxamide groups of PVPy‐g‐polyacrylamide were transformed into amino, aminoethylamido, and hydrazide functionalities terminating in primary amino or hydrazido groups. These provide sites for immobilizing proteins through their amino or carboxyl groups and, also, handles for attaching reagent molecules. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2163–2168, 1999     

Gamma radiation induced graft copolymerization of acrylamide onto poly(vinyl chloride) films

Grafting of acrylamide (AAm) onto poly(vinyl chloride) (PVC) films using gamma radiation has been carried out. The effects of different parameters on the graft yield have been investigated. These parameters include radiation dose, monomer concentration, solvent composition, types of inhibitors and acidity of the medium. In addition, the effects of the multifunctional monomers N,N′-methylene allyl amide (MAAm) and 2,4,6-triallyloxy-1,3,5 triazine (TARA) on the graft yield have been investigated. It has been found that methanol/water mixture in the ratio (1:1) is the proper diluent mixture for enhancing the graft copolymerization process. The presence of sulphuric acid in the reaction medium adversely affects the graft yield more than acetic acid. The presence of MAAm in the reaction medium markedly increases the graft yield, while TARA has practically no effect on the grafting process. Grafted films have been characterized and evidence of grafting has been obtained using thermal and spectroscopic analysis together with swelling measurements in water. © 1998 SCI.     

Copolymerization kinetics of poly(acrylonitrile‐ran‐2‐ethenyl‐pyridine) and its degradation apparent activation energy

2‐Ethenyl‐pyridine (EPD) was first used to successfully copolymerize with acrylonitrile (AN) in a H₂O/dimethyl formamide (DMF) mixture by using azobisisobutyronitrile as the initiator. Kinetics of copolymerization and degradation of poly(AN‐ran‐EPD) were discussed. The kinetic equation of copolymerization and the apparent activation energy of degradation of poly(AN‐ran‐EPD) were obtained. In H₂O‐rich reaction medium, copolymerization followed the suspension polymerization more, but in DMF‐rich reaction medium, copolymerization followed the solution polymerization more. Increase in DMF concentration in the solvent mixture lead to a rapid increase in the degradation apparent activation energy. The apparent activation energy decreased quickly with an increase in EPD concentration, and such a change became less prominent as the molar ratio of EPD/AN went beyond 3/100. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Surface graft copolymerization of 2‐hydroxyethyl methacrylate onto low‐density polyethylene film through corona discharge in air

The corona discharge technique was explored as a means of forming chemically active sites on a low‐density polyethylene (LDPE) film surface. The active species thus prepared at atmospheric pressure in air was exploited to subsequently induce copolymerization of 2‐hydroxyethyl methacrylate (HEMA) onto LDPE film in aqueous solution. The results showed that with the corona discharge voltage, reaction temperature, and inhibitor concentration in the reaction solution the grafting degree increased to a maximum and then decreased. As the corona discharge time, reaction time, and HEMA concentration in the reaction solution increased, the grafting degree increased. With reaction conditions of a 5 vol % HEMA concentration, 50°C copolymerization temperature, and a 2.0‐h reaction time, the degree of grafting of the LDPE film reached a high value of 158.0 μg/cm² after treatment for 72 s with a 15‐kV voltage at 50 Hz. Some characteristic peaks of the grafted LDPE came into view at 1719 cm^?1 on attenuated total reflectance IR spectra (C?O in ester groups) and at 531 eV on electron spectroscopy for chemical analysis (ESCA) spectra (O_1s). The C_1s core level ESCA spectrum of HEMA‐grafted LDPE showed two strong peaks at ～286.6 eV (? C ? O? from hydroxyl groups and ester groups) and ～289.1 eV (O?C ? O? from ester groups), and the C atom ratio in the ? C? O? groups and O?C? O groups was 2:1. The hydrophilicity of the grafted LDPE film was remarkably improved compared to that of the ungrafted LDPE film. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2881–2887, 2001     

Effects of synthesis conditions on radiation-induced graft copolymerization of methacrylic acid on to poly(vinyl chloride) films

Poly(vinyl chloride) (PVC) films were grafted with methacrylic acid (MAA) using a simultaneous-irradiation technique. The effect of solvent ratio (methanol-water) on grafting was studied and maximum grafting was found for an equivolume mixture of methanol and water. The graft level increased with increase of the plasticizer (dioctylphthalate) content in PVC. Grafting was found to be higher at low dose rate and increased linearly up to 0.25 Mrad for all dose rates and then levelled off. Grafting also increased continuously with increasing monomer concentrations up to 5.4mol/litre, but a linear increase in grafting was observed only up to 2.5 mol/litre. The dependences of rate of grafting on dose rate and monomer concentration were found to be 0.62 and 1.20 respectively.     

Radiation-induced graft polymerization of acrylonitrile onto isotactic polypropylene and poly(tetrafluoroethylene–ethylene) copolymer films

Direct radiation-induced grafting of acrylonitrile (AN) onto both isotactic polypropylene (IPP) and (tetrafluoroethylene–ethylene) copolymer (ET) films has been studied. The effect of grafting conditions such as inhibitor and monomer concentrations and irradiation dose on the grafting yield was investigated. Homopolymerization of acrylonitrile was reduced to a minimum using ferric chloride (FeCl₃), and the suitable optimum concentration of the inhibitor was found to be 0.1 wt%. The higher the monomer concentration, the higher the degree of grafting obtained. It was observed that the degree of grafting onto IPP was higher than onto ET, at given grafting conditions. The effect of aging on IPP was also examined. IR spectroscopy showed that IPP was susceptible to photooxidation by aging. The swelling behaviour and electrical conductivity of the graft and hydrolysed graft films were investigated. The electrical conductivity was improved by hydrolysis of polyacrylonitrile in the graft chains.     

Photoinitiated graft copolymerization of glycidyl methacrylate and 2-hydroxyethyl methacrylate onto polyacrylonitrile and application of the synthesized graft copolymers in penicillin–amidase immobilization

The photoinitiated graft copolymerization of hydroxyethyl methacrylate and/or glycidyl methacrylate onto polyacrylonitrile (PAN) and the applicability of the matrices synthesized in this way for penicillin–amidase immobilization are discussed. The copolymers are prepared by putting irradiated PAN fibers with preliminary adsorbed benzophenone on them into the polymerization feed that includes hydroxyethyl methacrylate and/or glycidyl methacrylate dissolved in a water–methyl ethyl ketone mixture. The degree of grafting varies between 11.7 and 46.0%, and its efficiency, between 27.8 and 78.9%. The concentration of epoxy groups in the synthesized copolymers is in the range between 210 and 2220 μmol/g. The reactivity ratios of the two comonomers are determined to be r_GM = 0.70 ± 0.15 and r_HEMA = 2.73 ± 0.14. The grafted copolymers containing HEMA units provide milder conditions for penicillin–amidase covalent binding. The optimum pH and temperature values of penicillin–amidase immobilized on these matrices are 7.5 and 45°C, respectively. © 1994 John Wiley & Sons, Inc.     

Fabrication and apparent kinetic study of poly(methyl methacrylate)/poly(octyl acrylate) and poly(octyl acrylate)/poly(methyl methacrylate) latex interpenetrating polymer networks

Two latex interpenetrating polymer networks (LIPNs) were synthesized with methyl methacrylate (MMA) and octyl acrylate (OA) as monomers, respectively. The apparent kinetics of polymerization for the LIPNs was studied. This demonstrates that network II does not have a nucleus formation stage. The monomers of network II were diffused into the latex particles of network I and then formed network II by in situ polymerization. It indicates that the polymerization of network I obeys the classical kinetic rules of emulsion polymerization. But the polymerization of network II only appears a constant‐rate stage and a decreasing‐rate stage. The apparent activation energies (E_a) of network I and network II of PMMA/POA were calculated according to the Arrhenius equation. The E_a values of POA as network I (62 kJ/mol) is similar to that of POA as network II PMMA/POA (60 kJ/mol). However, the E_a value of PMMA as network II POA/PMMA (105kJ/mol) is higher than that of PMMA as network I (61 kJ/mol). Results show that the E_a value of the network II polymerization is related to the properties of its seed latex. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

UV‐radiation induced graft copolymerization of methyl methacrylate onto sodium salt of partially carboxymethylated psyllium

UV‐radiation induced grafting of methyl methacrylate onto sodium salt of partially carboxymethylated psyllium has been carried out using ceric ammonium nitrate as a photoinitiator in an aqueous medium. The reaction variables including concentrations of initiator, nitric acid, monomer, and amount of the backbone as well as time and temperature have been varied for establishing the optimized reaction conditions for grafting. The influence of these reaction conditions on the grafting yields has been discussed. The overall activation energy of grafting has been calculated. The infrared spectroscopic, thermogravimetric analysis, and scanning electron microscopic techniques have been used for the characterization of graft copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface graft copolymerization of poly(methyl methacrylate) onto waste tire rubber powder through ozonization

Grinding of tires offers a promising opportunity for recycling waste rubber because fine waste tire rubber particle may be used as fillers and property modifiers in thermoplastic, elastomer, and thermoset blends. However, due to the lack of reactive sites on the WTR surface, the adhesion between WTR powder and matrix is poor. In this article, ozonization of waste tire rubber (WTR) powder was performed to produce some “immobile” reactive points (hydroperoxide groups) on the WTR surface. The free radical generated by the decomposition of hydroperoxide groups on WTR surface, was used to initiate graft polymerization of methyl methacrylate (MMA) onto the surface of WTR powder. The experimental results showed that MMA was successfully grafted onto the surface of WTR. The hydrophilicity of the MMA grafted WTR (MMA‐g‐WTR) was improved. The concentration of hydroperoxide groups and the graft degree were both increased with ozonization time. With increasing of polymerization time and polymerization temperature, the grafting degree increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

RAFT‐mediated graft polymerization of glycidyl methacrylate in emulsion from polyethylene/polypropylene initiated with γ‐radiation

The successful reversible addition‐fragmentation (RAFT)‐mediated graft polymerization of glycidyl methacrylate (GMA) in emulsion phase from polyethylene/polypropylene nonwoven fabric using 4‐cyano‐4‐[(phenylcarbonothioyl)thio]pentanoic acid under γ‐irradiation at ambient condition is reported. While conventional graft polymerization in emulsion phase yielded grafted materials with low of grafting (Dg) values [<7.5% at 10% (wt/wt) GMA], addition of RAFT agent to the graft polymerization system allowed the synthesis of polyethylene/polypropylene‐g‐poly(GMA) with more tunable Dg (8% ≤ Dg ≤ 94%) by controlling the grafting parameters. Relatively good control (PDI ～1.2 for selected grafting conditions) during polymerization was attained at 100:1 monomer‐to‐RAFT agent molar ratio. The number average molecular weight of free poly(glycidyl methacrylate) (PGMA) increased as a function of monomer conversion. NMR analyses of the free PGMA homopolymers indicate the presence of dithiobenzoate group from 4‐cyano‐4‐((phenylcarbonothioyl)thio) pentanoic acid on the polymer chain. The reactive pendant oxirane group of the grafted GMA can be modified for various environmental and industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45270.     

Ionic graft copolymerization. III. Graft copolymerization of β-propiolactone onto polyacrylonitrile containing diketene units

Polyacrylonitrile (PAN)–β-propiolactone (βPL) graft copolymer was synthesized by means of the ionic polymerization of βPL in the presence of polyacrylonitrile containing diketene units by using basic catalysts. A graft copolymer was produced by the copolymerization of βPL with the lactone ring in the trunk polymer. In this graft copolymerization method, the grafting efficiency was low. However, grafting efficiency increased with the mole ratio of polymeric lactone to βPL; also higher molecular weight of PβPL favored higher grafting efficiency. The reactivity ratio of polymeric lactone to βPL was estimated to be in the range of 0.1–0.3.     

Behaviour of poly(β-hydroxybutyric acid) in dilute solution

The refractive indices of poly(β-hydroxybutyric acid) (PHB) at four wavelengths have been determined via different procedures. Viscometric and light scattering measurements have been made on solutions of eight samples of PHB (M_w = 20·9 × 10³?929 × 10³ g mol^?1) in 2,2,2-trifluoroethanol. From the dependences of intrinsic viscosity and of radius of gyration on molar mass, the conformation of PHB in dilute solution is shown to be that of a random coil. The findings are discussed in relation to existing conflicting evidence on the conformation of this polymer.     

Polypeptide spheres. VII. Macroreticulation of spherical poly(γ-methyl-L-glutamate) beads

Spherical beads from poly(γ-methyl-L -glutamatate) alone were prepared using various diluents for macroreticulating by the “suspension and evaporation” method. The porosity and the pore size of the beads obtained were remarkably dependent on the chemical structure of a diluent. This is related to the specific miscibility of a diluent with poly(γ-methyl-L -glutamate). For example, decahydronaphthalene made the beads much more macroporous than tetrahydronaphthalene with similar hydrophobisity: the aromaticity of diluent increases the miscibility. However, it was found that long-chain alkyl compounds with a miscible group such as methyl dodecanoate, oleic acid, linoleic acid, and dialkyl-phthalate were not only very effective for macroreticulating, but also induced narrow pore-size distribution. In addition, the diluent influenced physicochemical properties of the beads to cause specific affinity to proteins.