Showing papers in "International Journal of Polymeric Materials in 2007"

Structural, Electrical and Optical Characterization of Pure and Doped Poly (Vinyl Alcohol) (PVA) Polymer Electrolyte Films

Abstract: A sodium ion conducting polymer electrolyte based on Poly (Vinyl Alcohol) (PVA) complexed with Sodium Iodide (NaI) was prepared using solution cast technique. The structural properties of composite PVA polymer electrolyte films were examined by XRD. The XRD results revealed that the amorphous domains of PVA polymer matrix increased in size with the increase of NaI salt concentration. The variation in film morphology was examined by scanning electron microscopy. FT-IR spectra studies for pure PVA and complexed films revealed the vibrational changes that occurred due to the effect of dopant salt in the polymer. DC conductivity was measured in the temperature range of 303–373° K and the conductivity was found to increase with the increase of dopant concentration as well as temperature. Optical absorption studies were made in the wavelength range 200–600 nm. The absorption edge, direct band gap, and indirect band gap values were evaluated.

Characterization of Galactomannan Gum from Fenugreek (Trigonella foenum-graecum) Seeds and Its Rheological Properties

Abstract: Galactomannan, a water-soluble heteropolysaccharide, was isolated from the seed of Chinese traditional medicine fenugreek. The polysaccharide was characterized by using both chemical and chromatographic procedures, as well as FT-IR, 1H NMR, 13C NMR spectroscopy. The results showed that the polysaccharide consists of D-mannopyranose and D-galactopyranose residues with a molar ratio of 1.2:1.0. The main chain of this galactomannan comprises β-(1,4)-linked D-mannopyranose residues, in which 83.3% of the main chain is substituted at C-6 with a single residue of α-(1,6)-D-galactopyranose. The galactomannan had a molecular weight Mw of 3.23 × 105 g mol−1 and an intrinsic water viscosity of 235 mL g−1. Fenugreek gum (seed endosperm) contains 73.6% galactomannan. The viscosity of fenugreek gum at 1% concentration is 286 mPa.s (30°C, 170 s−1). The viscosity of the solutions decreased sharply as the rate of shear increased, but rose with increased concentration, and decreased as the temperature of fully hydrated gu...

Synthesis and Characterization of Ppy-PVS, Ppy-pTS, and Ppy-DBS Composite Films

Abstract: Composite films of polypyrrole-poly(vinyl sulphonic acid) (Ppy-PVS), polypyrrole-p-toluene sulphonic acid (Ppy-pTS) and polypyrrole-dodecylbenzene sulphonic acid (Ppy-DBS) were synthesized on ITO coated glass, using electrochemical polymerization The synthesized films were characterized using electrochemical technique, electrical conductivity, UV-Vis spectroscopy, FTIR spectra, and scanning electron microscopy (SEM) This study reveals that Ppy-PVS composite films provide a polymer matrix with very good mechanical and environmental stability, uniform surface morphology, and higher conductivity, which are suitable for the immobilization of biocomponent

Effect of Coumarone-Indene Resin on Adhesion Property of SMR 20-Based Pressure-Sensitive Adhesives

Abstract: The viscosity, tack, and peel strength of a natural rubber (SMR 20)–based pressure-sensitive adhesive (PSA) was studied using coumarone-indene resin as the tackifier. The resin loading was varied from 0–80 parts per hundred parts of rubber (phr). Toluene was used as the solvent throughout the experiment. The viscosity of PSA was measured using a Haake Rotary Viscometer whereas loop tack and peel strength were determined using a Lloyd Adhesion Tester. PSA was coated onto the substrates using a SHEEN hand coater to give a coating thickness of 60 μm and 120 μm. Results show that the viscosity and tack of the adhesive increases with resin content due to the concentration effect of tackifier resin. However, for the peel strength, it increases up to 40 phr of resin for both coating thickness, an observation that is attributed to the wettability of substrates.

Novel Polyimide System Based on Nitro Displacement/Diels-Alder Reactions

Abstract: Poly(ether-imides) were prepared by two simultaneous reactions, that is, Diels-Alder reaction and nitro displacement reaction. Thus 3-nitrophthalic anhydride was reacted with furfuryl amine and the resultant amic acid was then reacted with three bismaleimides (2a–c) and disodium salt of bisphenol–A. The obtained polymers were treated with acetic anhydride to form cyclic imide, as well as aromatization of Diels-Alder adduct. The poly(ether-imide)s were characterized by IR spectral studies and theromgravimetry. A “in situ” polymerization on glass fibers was also carried out and the laminates were characterized by physical, mechanical, and chemical properties.

Mechanical properties of bismaleimides modified polysulfone epoxy matrices

Abstract: Epoxy resin has been chemically modified using 4, 8, and 12% of bisphenol-A based polysulphone along with three types of bismaleimides, namely [N, N′-bismaleimido-4,4′-diphenylmethane (BMI-1), 1,3-bis (maleimido) benzene (BMI-2) and 1,1′-bis (4-maleimidophenyl) cyclohexane (BMI-3)]. The epoxy hybrid matrices developed, in the form of castings, were used to characterize their mechanical properties like tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, hardness, and dynamic mechanical analysis as per ASTM standards. Data obtained from mechanical studies indicate that the introduction of hydroxyl terminated polysulfone into epoxy resin enhanced the value of impact strength to the extent of 48% due to the formation of flexible graft structures. Similarly, the incorporation of bismaleimides into epoxy resin also improved both tensile and flexural behavior of epoxy resin. Further, the introduction of combination of both polysulfone and bismaleimides into epoxy resin improv...

Synthesis, Characterization and Biodegradation Study of Low Molecular Weight Polyesters

Abstract: A series of low molecular weight aliphatic biodegradable polyesters were synthesized from 1,3-propanediol and dibasic acids by thermal polycondensation, in the bulk without catalyst in N2 atmosphere at 150°C. The synthesized aliphatic polyesters were characterized by 1H-NMR, FT-IR, solubility, solution viscosity, gel permeation chromatography, and diffential scanning calorimetry. The biodegradability of the synthesized polyester films was tested by enzymatic degradation in phosphate buffer (pH = 7.2) in presence of Rhizopus delemar lipase incubated at 37°C, and soil burial degradation at 30°C. SEM was used to study the surface morphology after incubation of the films. The result of biodegradation shows that the films become brittle on incubation and their surfaces change upon degradation. The biodegradability of the polyesters depends on the crystallinity of the polymers. The degradation was more pronounced in PPSu compared to PPAd.

Modelling of Mechanical Properties of Nanoparticle Filled Polyethylene

Abstract: A continuum-mechanics approach has been applied to model the mechanical properties of high density polyethylene (HDPE) filled with differently coated SiO2 nanoparticles. The tensile yield stress has been predicted with a finite-element model (FE-model) taking into account the microstructural features, e.g. matrix, filler content and the interphase formed around the filler. A good agreement between the experimental and modelled data has been found. Additionally, the FE-model has been compared with a semi-empirical model and an analytical model with similar input parameters to predict the composite property. It was found that all models are congruent with respect to solution space.

Cure Characteristics and Mechanical Properties of Natural Rubber–Layered Clay Nanocomposites

Abstract: The effect of interlayer distance of nanoclay on mechanical properties, cure characteristics, and swelling resistance of natural rubber (NR) in varying clay proportion were studied. X-ray diffraction results of nanocomposite with 10 phr of nanoclay showed the formation of an intercalated structure. The rate of vulcanization and maximum torque value of the nanocomposite are higher than the gum compound. Nanocomposites with clay having higher interlayer distance shows superior mechanical properties. Mechanical properties gradually increase with increase in clay loading up to 10 phr. A 50% increase in tensile strength and about 150% increase in modulus at 300% elongation were observed for the nanocomposite with 10 phr clay loading. Better barrier properties offered by the nanocomposites due to the presence of tortous path was confirmed by the Nielson's model.

Miscibility Studies of Polyesteramides of Linseed Oil and Dehydrated Castor Oil with Poly(vinyl alcohol)

Abstract: Blends of two polymers have been widely investigated to enhance or modify some of their physical or mechanical characteristics for specific applications. The investigation of miscibility of a pair of polymers is a necessary step in the investigation of the properties of the blends. Poly(vinyl alcohol)(PVA) is a commercial polymer that yields tough films of high tensile strength. They are, however, water soluble, restricting their applications. Vegetable oil constitutes a major resource for several polymeric products, such As alkyds, polyurethanes, polyepoxies, and polyesteramides. Polyesteramides, synthesized from different seed oils, have been used as an anticorrosive material but they fail to form free standing films. They can, therefore, be used for blending with PVA to lower its water sensitivity as well as to obtain free-standing films of a sustainable resource based polymer. In this study, linseed oil polyesteramide (LOPEA) and dehydrated castor oil polyesteramide (DCPEA), the source oils having dif...

Kinetics of Curing and Thermal Degradation of POSS Epoxy Resin/DDS System

Abstract: Polyhedral oligomeric silsesquioxanes epoxy resin (POSSER) was prepared from 3-glycidypropyl-trimethoxysilane (GTMS) and tetramethylammonium hydroxide (TMAH) by hydrolytic condensation. POSSER was characterized using Fourier-transformed infrared spectroscopy (FTIR), 1H-NMR, and liquid chromagraphy/mass spectrometry (LC/MS). The epoxy value of POSSER is 0.50 mol/100 g. The LC/MS analysis indicated that T10 is the majority and contain some amount of T8, besides, a trace T9 also exists. The curing kinetics of POSSER with 4,4′-diaminodipheny sulfone (DDS) as a curing agent was investigated by means of differential scanning calorimetry (DSC). The curing reaction order n is 0.8841 and the activation energy Ea is 61.06 kJ/mol from dynamic DSC analysis. Thermal stability and kinetics of thermal degradation were also studied by thermal gravimetric analysis (TGA). TGA results indicated that the temperature of POSSE/DDS system 5% weight loss is approximately 377.0°C, which is higher by 12.6°C than that of pure POSSE...

Properties of Polypropylene Composite Produced with Silk and Cotton Fiber Waste as Reinforcement

Abstract: The importance of polymer composites among industrial materials is due to their improved mechanical properties. In recent researches, mechanical and physical properties have been improved by way of making composites with fiber reinforcement. Silk and cotton fibers used in the textile industry have good physical and mechanical properties. In this study, composite structures were produced by using recycled Poly Propylene, PP, polymer with silk and cotton waste as fiber reinforcement in different ratios. The fiber dimensions of silk and cotton wastes were between 1 mm, 2.5 mm, and 5 mm. They were mixed in the ratios of PP/silk and cotton waste 97%/3 and 94%/6. The mixture of polymer composite was prepared with double screw extruder. The sample was tested for tensile strength, elongation, yield strength, elasticity modulus, izod impact strength, melt flow index (MFI), heat deflection temperature (HDT), and vicat softening temperature. Thermal transitions of the materials were determined with Differential Scan...

Optimization of Carboxymethylation of Starch in Organic Solvents

Abstract: A comparative study of the influence of ethanol, benzene, acetone, isopropanol, and mixtures of ethanol-acetone, ethanol-benzene, and ethanol-isopropanol as slurry media on the degree of substitution and viscosity of carboxymethyl starch during carboxymethylation is presented. It is shown that the degree of substitution increases with increasing acetone, isopropanol, or benzene content in the mixed solvent. After the same carboxymethylation steps the degree of substitution with ethanol/benzene mixture is higher than that with ethanol/isopropanol mixture.

Synthesis, Characterization and Glass Reinforcement of Poly(Ester Amido Imide)s

Abstract: Poly(ester amido imide)s (PEAI)s (IIIa–e) were prepared by the intermolecular Diels-Alder (DA) reaction of bismaleimide (II) having epoxy resin segment with various bisfurans (Ia–e) having amide bridge. The DA reaction was carried out with tetrahydrofuran as a solvent, as well as in bulk, followed by aromatization of DA polyadduct intermediates in the presence of acetic anhydride. All the resultant polymers, designated as poly(ester amido imide)s (PEAI)s, were characterized by elemental analysis, number average molecular weight, IR spectral studies and thermogravimetry. The PEAIs exhibit good thermal stability. Bismaleimide (II) and bisfurans (Ia–e) were polymerized (at 150 ± 10°C) by in situ DA intermolecular reaction into moderately thermally stable PEAIs. The glass fiber-reinforced composites (i.e., laminates) of all PEAIs were prepared and characterized by their chemical resistance and mechanical properties.

DSC Study of Syndiotactic Polypropylene/Organoclay Nanocomposite Fibers: Crystallization and Melting Behavior

Abstract: The effect of anisotropic particles of organophilic layered silicate on the crystallization and melting behavior of prepared nanocomposite systems was studied. The matrix was syndiotactic polypropylene (sPP). Organophilic layered silicate M-QDA filler was prepared by modification of hectorite SOMASIF ME 100 with octadecyl amine. The compatibilizer was isotactic polypropylene (iPP) grafted with maleic anhydride (iPP-g-MA). The silicate was exfoliated in situ within the sPP during the melting process to produce anisotropic nanoparticles. The sPP/M-ODA nanocomposite was spun at different drawing ratios. The resulting fibers were examined by differential scanning calorimetry. It was found that neither the spinning process nor the presence of nanofiller affected the crystallinity of the sPP matrix of the nanocomposite in comparison with the neat sPP. At a raised drawing ratio of the fibers slightly increased crystallinity of matrix was observed; however, it was still lower than the neat sPP fibers prepared at ...

Study of Optical and Structure Properties of Polyester (PET) and Copolyester (PETG) Fibers by Interferometry

Abstract: In this article results on the influence of drawing on the optical and structure properties of polyester (polyethylene terephthalate) and copolyester (glycol-modified polyethylene terephthalate) (4 wt% of ethylene glycol) fibers are reported. Refractive indices, intrinsic birefringence, mean polarizability per unit volume, optical orientation function, density, volume fraction of crystalline material, weight fraction crystallinity, and volume fraction of amorphous and work per chain of these fibers have been evaluated at different draw ratios. A comparison of optical and structure parameters for copolyester fiber and referenced monopolyester fiber has been done. This study has been carried out by means of computerized double-refracting Pluta interference microscope combined with opto-mechanical devices. Microinterferograms and relationships between the parameters obtained are given for illustration.

Sulphonated poly(ether ether ketone) proton exchange membranes for fuel cell applications

Abstract: Polymer electrolyte membrane fuel cells (PEMFCs) are promising new power sources for automotive and portable devices. Nafion® is the currently used membrane in PEMFCs. Although these membranes show high proton conductivity and excellent chemical stability, their high cost makes them unpractical for commercial purposes. Sulphonated poly(ether ether ketone) (SPEEK) ionomers were synthesized using chlorosulphonic acid as the sulphonating agent in dichloromethane medium. Homogeneous proton-conducting membranes were developed from the obtained SPEEK by solvent casting method. Membranes were assessed for their suitability in fuel cell applications. The extent of sulphonation was controlled by varying the reaction time, concentration of polymer, and concentration of sulphonating agent. The SPEEK membranes exhibit degree of sulphonation from 10 to 66%, ion exchange capacity from 0.29 to 1.92 meq/g and maximum water and methanol uptake up to 54 and 22%, respectively, at 25°C. The membranes were characterized by FT...

Effect of Nickel–Cobalt–Zinc Ferrite Filler on Magnetic and Thermal Properties of Thermoplastic Natural Rubber Composites

Abstract: A sample of Ni0.25Co0.25Zn0.5Fe2O4 ferrite was prepared by a double-staged sintering method in air. Thermoplastic natural rubber (TPNR) was prepared by melt blending of natural rubber (NR), liquid natural rubber (LNR), and high density polyethylene (HDPE) in an internal mixer Brabender Plasticorder PL 2000. Magnetic polymer composites were prepared from the ferrite and TPNR matrix using the same melt blending method at 135°C with mixing rate of 50 r.p.m. for 12 min. The fillers were varied from 5 to 30 weight percent. A uniform dispersion of the filler in the matrix was confirmed by thermogravimetric analysis (TGA). The density of the composites was determined using densitometer MD 200S. Magnetic properties were studied using a vibrating sample magnetometer (VSM) at room temperature (25°C). The results show that magnetization (M), saturation magnetization (MS), remanent magnetization (MR), initial susceptibility (χi) and initial permeability (μi) increase with increasing filler content at all compositions...

Synthesis and Evaluation of Some Detergent/Dispersant Additives for Lube Oil

Abstract: With increasing demands being placed on lubricants for automotive engines and transmissions, it has been necessary to work to improve the function of these lubricants. Modern lubricants are formulated from a range of base fluids and chemical additives to enhance their actions or to add new properties. In this study we have confined ourselves to the study of the detergent/dispersant type of additives based on preparation of polyisobutylene succinic anhydride (PIBSA) and then the reaction of PIBSA with different polyethylene glycols and the amination of the products by different polyamines. The compositions of the prepared compounds were determined by molecular weight, I.R. and H-NMR spectroscopy. The efficiency of the prepared compounds as antioxidants and detergents/dispersants was investigated. It was found that the prepared compounds have very good dispersancy power and the efficiency increases by increasing the number of –NH groups in the prepared compounds and by increasing the molecular weight of the...

Dynamic Mechanical Behavior of Piassava Fibers (Attalea funifera) Reinforced Polyester Composites

Abstract: This work compares the dynamic mechanical behavior of piassava fiber–reinforced polyester composites with the behavior of the neat resin matrix. The results obtained confirm previous data showing that the interface of piassava/polyester composites is stronger than the usual interfaces found when untreated lignocellulosic fibers are incorporated into common polyester matrices. This behavior was attributed to silica-rich protrusions found at the fibers' surface that aid to anchor the resin matrix and increase the stress transfer at the fiber–matrix interface.

Effect of Compatibilizer Type on Properties of 70:30 Polyamide 6/Polypropylene/MMT Nanocomposites

Abstract: PA6/PP nanocomposites with either polyethylene octene elastomer grafted maleic anhydride (POEgMAH) or PP grafted maleic anhydride (PPgMAH) as compatibilizer were prepared using co-rotating twin-screw extruder followed by injection molding. The mechanical and microstructural properties of the composites were investigated by means of tensile, flexural, and impact testing and by scanning electron microscopy (SEM). X-ray diffraction (XRD) was used to characterize the formation of nanocomposites. The result indicated that the miscibility of PA6/PP nanocomposites was improved with the addition of POEgMAH and PPgMAH. The impact strength of PA6/PP nanocomposite with POEgMAH increased about 5 times higher than uncompatibilized composite. Increment in tensile properties was observed when PPgMAH was used as compatibilizer. XRD results revealed that PA6/PP nanocomposites were successfully formed. Uniform dispersion of PP in matrix were observed through SEM, which showed the improvement of the compatibility between polymers.

Synthesis and Characterization of Conductive Blends of Polyaniline with Poly(azomethine ester)s

Abstract: Polyaniline (PANI) doped with HCl was blended with different poly(azomethine ester)s (10% by weight of PANI) and compressed into pellets. The blends were studied by Fourier Transform Infra-Red (FT-IR) and thermo gravimetric analysis (TGA). Electrical conductivities of the blends determined by four-point probe method, in the temperature range 32°C to 80°C, vary from 24.4 × 10−3 to 3.15 × 10−3 Scm−1. The TGA measurements show that weight loss occurred below 80°C is only about 2%.

Evaluation of Composites Miscibility by Low Field NMR

Abstract: Solid state nuclear magnetic resonance (NMR) is a powerful technique to analyze polymer composites. The use of proton relaxation data to evaluate the dispersity of the dispersion phase in the composite and its homogeneity are very wide. In this work PVC/silica composites were prepared using different ratios to obtain a new material to be used in chromatograph column for separation of plant extracts. Thus, this study used proton spin–lattice and spin-spin nuclear magnetic resonance relaxation data, determined in a low field NMR spectrometer as a method to characterize those composites in relation to silica dispersion as well as PVC/silica compatibility. From the relaxation data analyses, the best ratio of PVC/silica, according to the components dispersion and consequently composite compatibility, was 80/20, according to the determined T1 values.

Mechanical Properties and Morphology of Nitrile Rubber Toughened Polystyrene

Abstract: Mechanical properties and morphology of blends of polystyrene and finely powdered (uncrosslinked and crosslinked) nitrile rubber were studied with special reference to the effect of blend ratio. Blends were prepared by melt mixing polystyrene and nitrile rubber in an internal mixer at 180°C in the composition range of 0–20 wt% nitrile rubber. The tensile stress/strain properties and impact strength of the polystyrene/nitrile rubber blends were determined using injection molded test specimens. In comparison to the blends with uncrosslinked nitrile rubber, blends with crosslinked nitrile rubber showed higher tensile strength, elongation at break, Young's modulus, impact strength, flexural strength, and flexural modulus. The enhanced adhesion between the dispersed nitrile rubber phase and the polystyrene matrix results in an increase in mechanical properties. Scanning electron micrographs of the fractured surfaces confirm the enhancement in mechanical properties.

Effect of Poly(ethylene glycol) on Separations by Cellulose Acetate/poly(ether imide) Blend Membranes

Abstract: Ultrafiltration membranes are largely being applied for macromolecular and heavy metal ion separations from aqueous streams. In this study, cellulose acetate (CA) and polyetherimide (PEI) based ultrafiltration blend membranes prepared in the absence and presence of poly(ethylene glycol) 600 (PEG 600) in various compositions were subjected to the separation of macromolecular proteins such as bovine serum albumin (BSA), egg albumin (EA), pepsin and trypsin. Toxic heavy metal ions such as Cu(II), Ni(II), Zn(II) and Cd(II) were subjected to separation by the blend membranes by complexing them with the polymeric ligand polyethyleneimine. The effects of polymer blend compositions and additive concentrations on the rejection and permeate flux of both proteins and metal ions are discussed. In general, it was found that CA/PEI blend membranes displayed higher permeate flux and lower rejection compared to pure cellulose acetate membranes at all additive concentrations. The extent of separation of proteins was found...

Evolution of the Mechanical Properties of EPDM Vulcanizates by Compounding with Layered Organo-Montmorillonite

Abstract: Organoclay was compounded with EPDM using a two roll and cured by conventional sulfur curing system. The organoclay content was progressively increased from 0 to 15 phr of the EPDM rubber. The mechanical properties of the EPDM vulcanizates were evaluated by an Ekktron tensile testing machine. It has been found that tensile properties increased with nanoclay content. The observed trend was related mainly to the strong interaction between the rubber matrix and the nanoscaled filler (organoclay in this case) and subsequently to the improved crosslink density. Such improvement was attributed to the small size of the filler particles and to the amine functionality in the organoclay structure.

Hyperbranched Polyether as a Modifying Agent for Urea-Formaldehyde Resins—Hardness and Strength Control Tool

Abstract: A commercially available urea-formaldehyde (UF) resin was blended with a hyperbranched polyether (HBP) obtained from glycerol being a by-product in biodiesel production. The mechanical properties of the cured polymeric blends are described in this article. It was found that low addition (3 wt%) of the modifier significantly improves the hardness (16%) and the compressive shear strength (17%) of the polymer, whereas water absorption remains unaffected. It was also shown that blending UF resins with hyperbranched polyethers can be an effective tool for controlling mechanical properties and dimensional stability of the polymeric systems.

Free Radical Copolymerization of Methyl Methacrylate and Styrene with N-(4-Carboxyphenyl)maleimide

Abstract: The free radical copolymerization of methyl methacrylate (MMA) or styrene (St) with N-(4-carboxyphenyl)maleimide (CPMI) was carried with AIBN as an initiator in THF solvent at 80°C. A series of copolymers of MMA and St with CPMI were prepared using different feed ratios of comonomers. The values of monomer reactivity ratios (r1, r2) determined by Fineman-Ross and Kelen-Tudos methods are 0.26 and 2.51 in the CPMI/MMA system and 0.08 and 0.22 in the CPMI/St system. Alfrey–Price Q-e values for CPMI were calculated as Q = 1.05 and e = 0.41 in the CPMI/MMA system and Q = 1.21 and e = 0.91 in the CPMI/St system. The polymer samples have been characterized by solubility tests, intrinsic viscosity measurements, FT-IR and 1H-NMR spectral analysis, and thermo-gravimetric analysis. It was found that the initial and final decomposition temperatures increased with increasing the amount of CPMI in the copolymer. The integral procedural decomposition temperature and energy of activation of thermal degradation have also ...

Poly(vinyl alcohol) Based pH Responsive Semi-IPN Hydrogels: A Comparative Swelling Investigation

Abstract: The semi-interpenetrating polymer network (IPN) hydrogels composed of poly(vinyl alcohol) (PVA) and random copolymers of poly(acrylamide-co-sodium methacrylate), poly(AAm-co-NMA); poly(acrylamide-co-potassium methacrylate), poly(AAm-co-KMA); poly(acrylamide-co-maleic acid), poly(AAm-co-MA) were prepared by conventional co-polymerization employing ammonium persulphate (APS)/N,N,N1,N1-tetraethylmethylenediamine (TMEDA) as redox initiating system in presence of N,N1-methylenebisacrylamide (MBA) as a crosslinker The swelling behavior of these semi-IPN hydrogels were compared in detail in various swelling media, including different pH, salt, and biological fluids

Synthesis and Characterization of Polyamides Based on s-Triazine Moiety

Abstract: Seven polyamides containing s-triazine rings in the main chain were synthesized by high temperature polycondensation of 2-(β-naphthylamino)-4,6-bis(naphthoxy-3-carbonyl chloride)-s-triazine [NANCCT] with various aromatic diamines such as 4,4′-diaminodiphenyl [DADP], 4,4′-diaminodiphenylamide [DADPA], 4,4′-diaminodiphenylsulphone [DADPS], 4,4′-diaminodiphenylsulphonamide [DADPSA], 4,4′-diaminodiphenyl methane [DADPM], 2,4-diamino toluene [DAT] and p-phenylene diamine [PPDA]. All the polyamides were characterized by solubility tests, density measurements, viscosity measurements, IR spectra, NMR spectra, and thermogravimetric analysis. The polyamides had inherent viscosities in the range 0.88–1.16 g/dL in N,N′-dimethyl formamide at room temperature (30°C). All the polyamides showed good thermal stability at high temperatures and most of them were soluble readily at room temperature in polar solvents.