Chemical oxidative grafting of conducting poly(N‐methyl aniline) onto poly(ethylene terepthalate)

Detailed studies on the peroxidisulfate (PDS) initiated graft copolymerization of N‐methyl aniline (NMA) with poly(ethylene terepthalate) (PET) were carried out in p‐tolene sulfonic acid medium under nitrogen atmosphere. Experiments were designed to follow the rate of formation R_h of the poly(N‐methyl aniline (PNMA), simultaneously with the rate of grafting of PNMA onto PET. Effects of concentration of NMA, PDS, PET, time, and temperature on R_h and graft parameters were followed. Kinetic equations were deduced to correlate the changes in the rate with experimental conditions. Graft copolymers were isolated and grafting of PNMA onto PET was confirmed through FTIR, thermogravimetric analysis, and conductivity measurements. Tensile measurements showed that grafting of PNMA did not alter the tensile properties of PET. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 596–605, 2005     

Radiation‐induced grafting of glycidyl methacrylate onto high‐density polyethylene (HDPE) and radiation lamination of HDPE

Radiation‐induced grafting of glycidyl meth‐acrylate (GMA) onto high‐density polyethylene (HDPE) and the radiation lamination of HDPE by bulk grafting of GMA were reported. The effects of irradiation dose, monomer concentration, and atmosphere on grafting were investigated. The extent of grafting initially increased with irradiation dose and then remained almost constant. The extent of grafting was higher in 2M GMA than in 1M GMA at the same irradiation dose. The extent of grafting in nitrogen was higher than that in air. The grafted samples were characterized with FTIR spectrometry and thermogravimetric (TG) analysis. A carbonyl group was found on grafted HDPE samples, and the carbonyl index increased with the extent of grafting. TG analyses proved the existence of grafted materials on HDPE and the grafted GMA thermally decomposes at a temperature lower than that of HDPE. Strong adhesion could be obtained with radiation lamination of HDPE by bulk grafting of GMA. Benzophenone facilitates the grafting in a proper concentration range. The adhesion mechanism of the laminated samples was the entanglement of the grafted chains. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 772–779, 2005     

Physical and mechanical properties of poly(methyl methacrylate)‐grafted natural rubber synthesized by methyl methacrylate photopolymerization initiated by N,N‐diethyldithiocarbamate functions previously created on natural rubber chains

Well‐defined poly(methyl methacrylate) (PMMA)‐grafted natural rubbers (NRs) were prepared to study the structure–property relationships. Syntheses were achieved by the photopolymerization of methyl methacrylate initiated by N,N‐diethyldithiocarbamate groups created beforehand in side positions on the NR chains. With this procedure, good control of the graft density and PMMA content could be obtained. Thermal, morphological, and mechanical properties of NR‐g‐PMMA copolymers were studied as a function of the NR/PMMA composition and graft density. NR‐g‐PMMAs containing 15–80% grafted PMMA showed characteristics of heterogeneous materials (characterized by two glass‐transition temperatures, those of PMMA and NR, in differential scanning calorimetry). Under these conditions, they developed the morphology of thermoplastic elastomers with PMMA nodules dispersed in the rubber matrix when the PMMA content was near 20%; conversely, they developed the morphology of softened thermoplastics with rubber nodules dispersed in PMMA when the PMMA content was near 80%. Graft copolymers containing about 20% PMMA remained essentially rubbery, but they were already different from pure NR. On the other hand, the thermal stability of NR wash improved after the introduction of PMMA grafts onto NR chains. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Biodegradation of starch and acrylic‐grafted starch by Aspergillus niger

The biodegradation of starch and grafted starch by Aspergillus niger was examined. The grafted polymers were poly(methyl methacrylate) (PMMA) and poly(butyl acrylate) (PBA). Thermogravimetric analysis, Fourier transform infrared, and scanning electron microscopy were used to determine the morphology and degradation degree of each material. The temperature of maximum decomposition for starch decreased as enzymatic degradation proceeded, and it was completed on the 8th day of culturing in a liquid medium. Grafted samples with PMMA and PBA achieved degradation of their starch moiety. PBA in starch‐g‐PBA samples hindered the accessibility of the enzymes to the degradable material, and this resulted in a longer degradation time. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2764–2770, 2003     

Synthesis and physicochemical study of polyester polyols of epoxy resin of 2,4,6‐tris(4‐hydroxyphenyl)‐1,3,5‐triazine and their polyurethanes

Polyester polyols of ricinoleic acid (ETPRA), oleic acid, linoleic acid (ETPLA), and rosin (ETPR) and epoxy resin of 2,4,6‐tris(4‐hydroxyphenyl)‐1‐3‐5‐triazine (ETP) and their polyurethanes (PUs) were synthesized and characterized by Fourier transform infrared spectroscopy, NMR, differential scanning calorimetry, and thermogravimetric analysis techniques. The PU films showed the following density order: ETPRPU600 > ETPRAPU600 > ETPLAPU600. ETPLAPU600 showed good tensile strength and volume resistivity values compared to ETPRAPU600 and ETPRPU600. All three PUs showed good electric strength. ETPLAPU600 showed almost double the electric strength of ETPRAPU600 and ETPRPU600. The incorporation of soft‐segment poly(ethylene glycol) 600 into PU chains resulted in the flexibility of the films. The PU films showed a high water absorption tendency in water, acidic, and saline environments, and they degraded in an alkaline environment. The weight gain tendency of the films was due to surface solvolysis and was also probably due to microcrack formation. The polyester polyols and PUs were thermally stable up to about 167–221 and 184–214°C, respectively, and followed multistep degradation reactions with either fractional or integral order (0.43–2.71) degradation kinetics. Thus, the structure of the PUs affected the studied physicochemical properties of the films. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40203.     

Synthesis and characterization of dextrin‐grafted polypropylene

We carried out the graft copolymerization of the water‐soluble natural polymer dextrin onto preirradiated polypropylene (PP) in an aqueous medium using benzoyl peroxide (BPO) as the radical initiator. PP was irradiated by γ rays from a Co⁶⁰ source at a constant dose rate of 3.40 kGy/h to introduce hydroperoxide linkages, which served as the sites for grafting. The graft copolymerization was studied as a function of different reaction parameters, and the maximum percentage grafting (P_g; 55%) of dextrin onto PP was obtained at optimum conditions of [BPO] = 5.165 × 10⁻² mol/L, temperature = 60°C in 120 min with 15 mL of water. Different grafting parameters, such as the percentage apparent grafting, percentage grafting, and percentage true grafting have been evaluated. The graft copolymers were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Swelling studies were carried out in pure, binary, ternary, and quaternary solvent systems composed of water, ethanol (EtOH), dimethyl sulfoxide (DMSO), and N,N‐dimethylformamide (DMF) at different ratios. The maximum swelling percentage PP‐g‐dextrin (both composite and true graft) was observed in pure DMSO and DMF followed by EtOH and water. Water‐retention studies of PP and PP‐g‐dextrin (both composite and true graft) were investigated at different time periods, temperatures, and pH values. The maximum percentage water retention of PP‐g‐dextrin (composite, 124%) was observed at 8 h and 50°C in a neutral medium (pH 7). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Irradiation grafting of methyl methacrylate monomer onto ultra‐high‐molecular‐weight polyethylene: An experimental design approach for improving adhesion to bone cement

The grafting of methyl methacrylate (MMA) onto ultra‐high‐molecular‐weight polyethylene (UHMWPE) and chromic acid etched UHMWPE was conducted with a preirradiation method in air in the presence of a Mohr salt and sulfuric acid. The grafted samples were characterized by Fourier transform infrared (FTIR) spectroscopy, a gravimetric method, differential scanning calorimetry, scanning electron microscopy (SEM), and interfacial bonding strength measurements. The FTIR results showed the presence of ether and carbonyl groups in the MMA‐grafted UHMWPE (MMA‐g‐UHMWPE) samples. The Taguchi experimental design method was used to find the best degree of grafting (DG) and bonding strength. The efficient levels for different variables were calculated with an analysis of variance of the results. SEM micrographs of MMA‐g‐UHMWPE samples showed that with increasing DG and chromic acid etching, the MMA‐g‐UHMWPE rich phase increased on the surface; this confirmed the high interfacial bonding strength of the grafted samples with bone cement. The grafting of the MMA units onto UHMWPE resulted in a lower crystallinity, and the crystallization process proceeded at a higher rate for the MMA‐g‐UHMWPE samples compared to the initial UHMWPE; this suggested that the MMA grafted units acted as nucleating agents for the crystallization of UHMWPE. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Kinetic study of the thermal decomposition of (2‐phenyl‐1,3‐dioxolane‐4‐yl) methyl methacrylate and 2‐hydroxyethyl methacrylate copolymers

The kinetics of nonisothermal decomposition of (2‐phenyl‐1,3‐dioxolane‐4‐yl) methyl methacrylate (PDMMA), 2‐hydroxyethyl methacrylate (HEMA), and vinyl‐pyrrolidone (VPy) copolymers were investigated by thermogravimetry (TG) and differential thermal analysis (DTA). The data indicated that the major weight loss occurs in the range of 270 to 450°C. The decomposition characteristics showed essentially two regimes and varied depending on the temperature and the copolymer composition. The apparent kinetic parameters of the decompositions were estimated from both TG and DTA data by using the alternative calculation methods. The results suggest that the weight loss rates may be represented, depending on the type of sample, by a reaction model of overall order 1.0 to 1.6, with an activation energy of approximately 65–95 kJ mol^?1. The DTA data estimated considerably higher values for the overall activation energies, around 198–240 kJ mol^?1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1500–1508, 2005     

Halogen‐free flame‐retardant rigid polyurethane foams: Effect of alumina trihydrate and triphenylphosphate on the properties of polyurethane foams

Rigid polyurethane foam (PUF) filled with mixture of alumina trihydrate (ATH) and triphenyl phosphate (TPP) as fire retardant additive was prepared with water as a blowing agent. In this study, the ATH content was varied from 10 to 100 parts per hundred polyol by weight (php), and TPP was used at a higher loading of ATH (75 and 100 php) in a ratio of 1 : 5 to enhance the processing during PUF preparation. The effects of ATH on properties such as density, compressive strength, morphological, thermal conductivity, thermal stability, flame‐retardant (FR) behavior, and smoke characteristics were studied. The density and compressive strength of the ATH‐filled PUF decreased initially and then increased with further increase in ATH content. There was no significant change in the thermal stability with increasing ATH loading. We determined the FR properties of these foam samples by measuring the limiting oxygen index (LOI), smoke density, rate of burning, and char yield. The addition of ATH with TPP to PUF significantly decreased the flame‐spread rate and increased LOI. The addition of TPP resulted in easy processing and also improved FR characteristics of the foam. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

UV‐radiation–induced preirradiation grafting of methyl methacrylate onto lignocellulose fiber in an aqueous medium and characterization

The preirradiation method of grafting has been established by ultraviolet radiation. Methyl methacrylate (MMA) was grafted onto jute fiber in an aqueous medium. The variation of graft weight with UV‐radiation time, monomer concentration, and reaction time was investigated. The conversion of monomer into homopolymer and graft copolymer was evaluated. The graft weight passes through a maximum value (～ 122%) with UV‐radiation time. The optimum value of the monomer concentration was evaluated for maximum degree of grafting. Graft copolymerization of MMA onto lignocellulose fiber significantly increases the elongation at break (～ 65%) compared to that of the “as‐received” sample. However, a linear decrease on breaking load was observed with the increase of graft weight. The estimation of degree of grafting was achieved using an IR technique by correlating band intensities with the degree of grafting. Considering the water‐absorption property, the grafted sample showed a maximum up to 61% decrease in hydrophilicity compared to that of the as‐received sample. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1667–1675, 2004     

Photopolymerization and thermal behavior of phosphate diacrylate and triacrylate used as reactive‐type flame‐retardant monomers in ultraviolet‐curable resins

Tri(acryloyloxyethyl)phosphate (TAEP) and di(acryloyloxyethyl)ethyl phosphate (DAEEP) were used as reactive‐type flame‐retardant monomers along with commercial epoxy acrylate and polyurethane acrylate oligomers in ultraviolet (UV)‐curable resins. The concentrations of the monomers were varied from 17 to 50 wt %. The addition of the monomers greatly reduced the viscosity of the oligomers and increased the photopolymerization rates of the resins. The flame retardancy and thermal degradation behavior of the UV‐cured films were investigated with the limiting oxygen index (LOI) and thermogravimetric analysis. The results showed that the thermal stability at high temperatures greater than 400°C and the LOI values of the UV‐cured resins, especially those containing epoxy acrylate, were largely improved by the addition of the monomers. The dynamic mechanical thermal properties of the UV‐cured films were also measured. The results showed that the crosslink density increased along with the concentrations of the monomers. However, the glass‐transition temperature decreased with an increasing concentration of DAEEP because of the reduction in the rigidity of the cured films, whereas the glass‐transition temperature increased with the concentration of TAEP because of the higher crosslink density of the cured films. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 185–194, 2005     

Synthesis and characterization of microcrystalline cellulose‐graft‐poly(methyl methacrylate) copolymers and their application as rubber reinforcements

In this study, redox‐initiated free radical graft copolymerization of microcrystalline cellulose (MCC) and methyl methacrylate (MMA) has been carried out in aqueous media to develop a novel cellulose‐based copolymer. Cerium ammonium nitrate was used as the initiator in the presence of nitric acid. Effects of monomer concentration, initiator concentration, polymerization time, and polymerization temperature on the graft parameters of copolymers were studied. The successful grafting copolymerization between MCC and MMA was validated through attenuated total reflection, wide‐angle X‐ray diffraction, field‐emission scanning electron microscopy, and thermal gravimetric analysis. In comparison to native MCC, the resultant copolymers exhibited enhanced thermal stability and better compatibility with natural rubber, suggesting its potential application as reinforcement material in rubber industry. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42666.     

Swelling and thermal behaviors of a starch‐based superabsorbent hydrogel with quaternary ammonium and carboxyl groups

A starch‐based superabsorbent hydrogel with quaternary ammonium and carboxyl groups is synthesized in aqueous solution. Various factors, including the initiator dose, the crosslinker dose, and the dose and the concentration of the acrylate monomer, as well as the polymerization temperature, are investigated in terms of the swelling in distilled water and in a 0.9% NaCl solution. Furthermore, the thermal degradation of the modified starch graft copolymer is studied under an air atmosphere. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2392–2398, 2005     

Free‐radical copolymerization of [(4‐isopropyl phenyl) oxycarbonyl] methyl methacrylate with acrylonitrile and methyl methacrylate

The present investigation has been achieved in accordance with the Diels–Alder reaction (1,4 cycloaddition) to produce a new halogenated bicyclic adduct. ortho‐Bromoallylbenzoate is a new dienophile that was prepared in a pure form, and its structure was confirmed. The Diels–Alder syntheses of hexachlorocyclopentadiene and the new dienophile were studied to determine the optimum condensation reaction conditions under a temperature range of 90–160°C, reaction times of 1–8 h, and molar diene/dienophile ratios from 1:1 to 5:1 as a consequence. The optimum conditions reached were a temperature of 140°C, an initial diene/dienophile molar ratio of 3:1, and a duration time of 6 h. The maximum stoichometric yield under these optimum conditions (82.5%) was obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2331–2338, 2003     

Direct polycondensation of N‐trimellitylimido‐L‐isoleucine with aromatic diamines

N‐Trimellitylimido‐L ‐isoleucine (3) was prepared from the reaction of trimellitic anhydride with L ‐isoleucine [L ‐2‐amino‐3‐methylvalerianic acid or (2S,3S)‐2‐amino‐3‐methyl‐n‐valerinic acid] in an N,N‐dimethylformamide solution at the refluxing temperature. The direct polycondensation reaction of the monomer imide diacid (3) with 1,4‐phenylenediamine, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenylsulfone, diaminodiphenylether, 1,5‐naphthalendiamine, 2,4‐diaminotoluene, and 1,3‐phenylenediamine was performed in a medium consisting of triphenyl phosphite, N‐methyl‐2‐pyrolidone (NMP), pyridine, and calcium chloride. The polycondensation was performed under two different conditions: in one method, the reaction mixture was heated in an NMP solution at 60, 90, and then 130°C for different periods of time, and in the other method, the reaction mixture was refluxed only for 1 min in the same solvent. The resulting poly(amide imide)s (PAIs), with inherent viscosities of 0.21–0.37 dL/g, were obtained in high yields. All of these compounds were fully characterized by IR spectra, elemental analyses, and specific rotation measurements. Some structural characterizations and physical properties of these new optically active PAIs were examined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 116–122, 2003     

Radiation‐induced GMA/DMAA graft copolymerization onto porous PE hollow‐fiber membrane

Radiation‐induced graft copolymerization is a powerful technique to prepare a grafted chain with the desired properties pending onto the trunk material. In this work, a polyethylene hollow‐fiber membrane was modified by this technique. The monomers glycidyl methacrylate (GMA) and N,N‐dimethylacrylamide (DMAA) were cografted onto macroporous polyethylene hollow fiber with a grafting degree in the order of 200%. DMAA/GMA cografted membranes were compared to GMA grafted ones for the introduction of an amino acid as a specific ligand. Grafted membranes with a copolymer composition between 0 and 2 DMAA/GMA were prepared by soaking them in solutions of different mixtures of monomers. Copolymers were characterized by FTIR and their composition was estimated by the analysis of the ratio of carbonyl signals. Copolymers with a higher proportion of DMAA showed improved hydrophilic properties and higher conversion rates of epoxy groups on phenyalanine ligands than those of the GMA grafted ones. However, copolymers with a DMAA/GMA ratio higher than 1 showed a detrimental effect on the pure water flux. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1646–1653, 2003     

Preirradiation‐induced emulsion graft polymerization of glycidyl methacrylate onto poly(vinylidene fluoride) powder

An epoxy‐group‐containing monomer, glycidyl methacrylate (GMA), was grafted onto poly(vinylidene fluoride) powder via preirradiation‐induced emulsion graft polymerization. The existence of graft chains was proven by chemical structure characterization with Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy analysis. The degree of grafting was calculated by means of fluorine content analysis. A kinetic study indicated that, with the emulsion graft polymerization system, the GMA conversion rate was high, exceeding 80%. The variation in the molecular weight of the grafted polymer was measured by gel permeation chromatography, and its crystallinity was investigated with differential scanning calorimetry. The epoxy groups in graft chains were found to be suitable for further chemical modification. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Characterization of hydrogels prepared by the γ irradiation of aqueous solutions of acrylamide and N‐vinyl‐2‐pyrrolidone comonomers

Copolymer hydrogels were prepared through the γ irradiation of aqueous solutions composed of different ratios of acrylamide (AAm) and vinyl pyrrolidone (VP) monomers. The chemical structure, thermal stability, and structural morphology of the hydrogels were characterized with Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy, respectively. The IR spectroscopy analysis showed the formation of copolymerization and the presence of hydrogen bonding. The TGA study showed that the AAm/VP‐based hydrogels possessed higher thermal stability than polyacrylamide (PAAm). However, the thermal stability of the AAm/VP hydrogels increased with an increasing ratio of the VP component. The study of the swelling kinetics in water showed that all the hydrogels reached the equilibrium state after 24 h. However, the AAm/VP‐based hydrogels showed swelling in water that was lower than that of the hydrogel based on pure AAm. Meanwhile, the degree of swelling of the AAm/VP‐based hydrogels decreased with an increasing ratio of VP in the feeding solutions. The results showed that the PAAm and AAm/VP‐based hydrogels prepared at 50 kGy were affected by a change in the temperature around 25°C, whereas the hydrogels prepared at 25 kGy did not show this characteristic. However, the hydrogels prepared at different doses displayed reversible pH character. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Thermal behavior of some homogeneously polymethyl methacrylate (PMMA)‐grafted high α‐cellulose products

The graft copolymerization of methyl methacrylate (MMA) onto high α‐cellulose was carried out homogeneously in an N,N‐dimethyl acetamide/lithium chloride solvent system by using benzoyl peroxide as radical initiator. The rate of grafting was evaluated as a function of concentrations of initiator and monomer, reaction time, and temperature. The grafted products were characterized with the help of infrared spectroscopy, whereas the thermal decomposition of optimum PMMA‐grafted high α‐cellulose was studied using TGA, DTG, and DTA techniques at two heating rates, 10 and 20°C/min, in nitrogen atmosphere in the range of room temperature to 650°C. Three major decomposition steps were identified and the relative thermal stabilities of the PMMA‐grafted high α‐cellulose products were assessed. The kinetic parameters for the three decomposition steps were estimated with the help of two well‐known methods. The thermal stability of the grafted products decreased with the increase of graft yield (GY). Crystallinity or peak intensity of wide‐angle X‐ray diffraction patterns decreased with the increase of GY. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3471–3478, 2004     

Crystallinity evolution of soft segments during the synthesis of polyester‐based waterborne polyurethane

Polyester‐based waterborne polyurethane (WPU) dispersions having poly(ethylene glycol) adipate diol, isophorone diisocyanate, and hexamethylene diisocyanate as the main raw materials were synthesized by an acetone process. In each step of the synthesis process, the intermediate products were collected, and the crystallization morphologies and relative crystallinity (X) of the soft segments (SSs) in their films were investigated by means of polarizing optical microscopy, differential scanning calorimetry, and X‐ray diffraction. The fracture surfaces and thermostability of the intermediate films were also investigated by scanning electron microscopy (SEM) and TGA, respectively. The results show that the crystalline dimensions of the SSs decreased substantially during the synthesis process of WPU. X of the SSs decreased after the prepolymerization reaction and increased after the hydrophilic chain‐extending reaction, then decreased after emulsification, and finally increased after the secondary chain‐extending reaction. Moreover, The SEM photos indicate that with decreasing crystalline dimensions, the fracture mechanisms of the intermediate films varied gradually from brittle failure to ductile fracture. The thermostability of the intermediates obtained in each step of the synthesis process was in accordance with the variation tendency of the X of the SSs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40270.