Showing papers in "Journal of Macromolecular Science, Part A in 2005"
TL;DR: In this article, the synthesis and characterization of homo and copolymer derivatives of PAA, along with the application and biodegradability in comparison with the other polymer in use, is discussed briefly.
Abstract: Poly(aspartic acid) (PAA) being biodegradable is suitable for various industrial medical and agricultural applications to replace many non‐biodegradable polymers in use Poly(aspartic acid) can be synthesized by different methods with and without catalyst in different forms such as polysuccinimide, either hydrolyzed to acid or salt The polymer of (aspartic acid) is present in different forms such as α,β and L, D isomers The conformational analysis of poly(aspartic acid) was done by various analytical methods Different combinations of these two isomer present in different percentage can be detected by various methods such as Hoffman degradation, IR, and NMR spectroscopic analysis From the standard test for biodegradability, it was shown that the polymer is fully biodegradable In this review, synthesis and characterization of homo and copolymer derivatives of PAA, along with the application and biodegradability in comparison with the other polymer in use, is discussed briefly
136 citations
TL;DR: In this paper, a super absorbing hydrogel hybrid composed of arabic gum (AG) and acrylamide (AM)/acrylic acid (AA)•potassium acrylate (AK) was prepared using a highly practical, homogenous solution polymerization process, conducted under normal atmospheric conditions.
Abstract: Novel super‐absorbing hydrogel hybrids composing arabic gum (AG) and acrylamide (AM)/acrylic acid (AA)‐potassium acrylate (AK) were prepared using a highly practical, homogenous solution polymerization process, conducted under normal atmospheric conditions. The unique characteristics of the gum and the redox pair initiating system (persufate/metabisulfite) favored the crosslinking polymerization, run under concentrated conditions without a need to heat. To produce hydrogel hybrids having the highest gel content and the highest swelling capacity, the preparative process was systematically studied through investigation of the certain reaction variables, i.e., the concentration of AG, initiator, crosslinker, monomer, and AM/AA‐AK mole ratio. The spectral and thermal characteristics of the optimally prepared hydrogel were studied using FTIR spectroscopy and thermogravimetric analysis, respectively.
53 citations
TL;DR: In this article, electrospun TiO2 nanofibers were employed to the quasi-solid state dye-sensitized solar cells with porous electrodes, which enhanced the penetration of viscous polymer gel electrolytes.
Abstract: Electrospun TiO2 nanofibers were employed to the quasi‐solid state dye‐sensitized solar cells with porous electrodes, which enhanced the penetration of viscous polymer gel electrolytes. The morphology of electrospun TiO2 fibers was affected by the electrospinning parameters such as the types of polymers, the concentration of polymer and titanium(IV) propoxide (TiP), the ratio of TiP/PVAc. The TiO2 fibers electrospun from poly(vinyl acetate) matrix formed the one‐dimensionally aligned fibrillar morphology as an islands‐in‐a‐sea structure. The new TiO2 electrodes demonstrated that the photocurrent generation with polymer gel electrolytes was over 90% of the performance in a dye‐sensitized solar cell with liquid electrolytes.
47 citations
TL;DR: Gelatin (Type A) particles were prepared by a single W/O emulsion technique and characterized by infrared (IR) spectra, scanning electron microscopy (SEM) and particle size analysis as discussed by the authors.
Abstract: Gelatin (Type A) particles were prepared by a single W/O emulsion technique and characterized by infrared (IR) spectra, scanning electron microscopy (SEM) and particle size analysis Whereas the IR spectra clearly confirmed the presence of gelatin and sulphamethoxazole (SM) in the loaded nanoparticles, the scanning electron micrograph (SEM) image depicts smooth surface, spherical shape and uneven size of nanoparticles (100 to 300 nm) The nanoparticles were evaluated for their potential to act as a carrier of sulphamethoxazole drug It was found that the amount of released SM increases with increasing percent loading of the drug in the range 18 to 39% The chemical architecture of nanoparticles was also found to influence its drug‐releasing capacity It was observed that in the case of an increase in gelatin and crosslinker (gluteraldehyde) concentrations in the range 40–90 g and 53–318 mM, respectively, the amount of released SM initially increases up to 80 g of gelatin and 106 mM of crosslinker co
39 citations
TL;DR: In this article, composites of fibrin, chitosan, and gelatin were crosslinked with glutaraldehyde to obtain the maximum tensile strength of the composite.
Abstract: Composites, in film form, containing physiologically clotted fibrin, chitosan and gelatin were prepared and crosslinked with glutaraldehyde. The films were characterised for their IR spectroscopy, water absorption capacity (WAC) at different pH conditions, mechanical properties and scanning electron microscopy (SEM). Fibrin+gelatin films gave higher WAC values in all the pH ranges (2,7 and 10) studied. However, with the addition of chitosan, the WAC values of the composite decreased. This was attributed to the crosslinking of glutaraldehyde with the hydrophilic groups available on chitosan and gelatin/fibrin. The amount of individual constituents, which gave maximum tensile strength to the FCG composite, was optimized. SEM pictures of the FCG have exhibited the fibrous and porous nature of the composite.
32 citations
TL;DR: In this paper, a modified shrinking core model with a depleting product was proposed for the decomposition of waste poly(ethylene terephthalate) (PET) in the presence of aqueous potassium hydroxide solution.
Abstract: Hydrolytic decomposition of waste poly(ethylene terephthalate) (PET) is studied in the presence of an aqueous potassium hydroxide solution. A modified shrinking core model with a depleting product ...
31 citations
TL;DR: In this paper, three different types of epoxy resins based on an unmodified epoxy (diglycidyl ether of bisphenol‐A), polyurethane (PU) modified epoxy and silicone modified PU epoxy matrices were developed.
Abstract: Three different types of epoxy resins based on an unmodified epoxy (diglycidyl ether of bisphenol‐A), polyurethane (PU) modified epoxy and silicone modified polyurethane‐epoxy matrices were developed. Epoxy resin was modified with PU prepolymer and hydroxyl terminated poly (dimethyl siloxane), also referred to as ‘silicones’ using a silane crosslinking agent and tin catalyst. Aromatic polyamine adduct (A), diethylenetriamine (B) and polyamidoamine (C) were used as epoxy curatives. The formation of intercrosslinked network was confirmed using Fourier transform‐infrared (FT‐IR) spectra and viscosity data. Thermo gravimetric analysis revealed reduced thermal stability for PU (10 wt%) modified epoxy, whereas the incorporation of silicone (10 wt%) into PU modified epoxy matrix improved their thermal properties. The morphology of silicone modified PU‐epoxy was also studied by scanning electron microscopy (SEM).
30 citations
TL;DR: In this article, a new monofunctional atom transfer radical polymerization (ATRP) initiator was synthesized by condensation of 2 −bromopropanoyl bromide with 1 −hydroxycyclohexyl phenyl ketone (HCPK), Irgacure 184 and characterized.
Abstract: A new monofunctional atom transfer radical polymerization (ATRP) initiator was synthesized by the condensation of 2‐bromopropanoyl bromide with 1‐hydroxycyclohexyl phenyl ketone (HCPK), Irgacure 184 and characterized. The ATRP of methyl methacrylate (MMA) in dry toluene at 90°C by means of this initiator in conjunction with a cuprous complex Cu(I)Cl/bipyridine (bpy) yields poly(MMA) with a photoactive alkoxy phenyl ketone end group. The gel permeation chromatography (GPC) and IR, H‐NMR, UV, and fluorescence spectroscopic studies revealed that low‐polydispersity poly(MMA) with photoinitiator functionality at the end of the chain was obtained. The obtained end‐functional PMMA macrophotoinitiator was used in photoinduced free radical polymerization of styrene (St) to produce PMMA‐b‐PSt upon irradiation via α‐cleavage of the incorporated phenyl ketone end group. This block copolymer was characterized by GPC and H‐NMR measurements.
29 citations
TL;DR: In this article, the effect of changing pH, temperature, ionic concentration, and applied electric fields on the swelling of the semi-interpenetrating polymer networks (semi-IPNs) was investigated.
Abstract: Semi‐interpenetrating polymer networks (semi‐IPNs) composed of chitosan and polyacrylamide (PAAm) hydrogels have been prepared, and the effect of changing pH, temperature, ionic concentration, and applied electric fields on the swelling of the hydrogels was investigated. The swelling kinetics increased rapidly, reaching equilibrium within 60 min. The semi‐IPN hydrogels exhibited a relatively high swelling ratios of 385%–569% at T=25°C. The swelling ratio increased with decreasing pH below pH=7 due to the dissociation of ionic bonds. The swelling ratio of the semi‐IPN hydrogels was pH, ionic concentration, temperature, and electric field dependent. Differential scanning calorimetry (DSC) was used to determine the volume of free water in the semi‐IPN hydrogels, which was found to increase with increasing PAAm content.
29 citations
TL;DR: In this paper, a binary hydrophilic blend of poly(acrylamide•co−methylene bis acrylamides) grafted polyvinyl alcohol (PVA) and gelatin (GEL) was prepared by redox polymerization method and the end product was characterized by infra red (IR) spectral analysis, differential scanning calorimety (DSC) measurements, and scanning electron micrograph (SEM).
Abstract: Binary hydrophilic blends of poly(acrylamide‐co‐methylene bis acrylamide) grafted polyvinyl alcohol (PVA) and gelatin (GEL) were prepared by redox polymerization method and the end product was characterized by infra red (IR) spectral analysis, differential scanning calorimety (DSC) measurements, and scanning electron micrograph (SEM). Network parameters such as molecular weight between crosslinks (Mc) and crosslink density of the hydrogel were also determined by swelling measurements. In addition, the blend hydrogels were assessed for their water sorption characteristics and influence of various factors such as composition of the blend, pH and temperature of the swelling bath and, the presence of electrolytes were investigated on the water uptake potential of blend hydrogels.
28 citations
TL;DR: In this paper, the effect of chemical aging on the performance of PMMA/TPU blends has been studied and the impact strength has been found to increase significantly with an increase in the percentage of TPU up to 20%.
Abstract: Blends of poly(methyl methacrylate) (PMMA) and thermoplastic polyurethane (TPU) in different compositions viz., 95/5, 90/10, 85/15 and 80/20 (by wt/wt, % of PMMA/TPU) were blended by melt mixing using a twin‐screw extruder. All the PMMA/TPU blends have been characterized for physico‐mechanical properties such as density, melt flow index, tensile behavior and izod impact strength. The impact strength of the PMMA/TPU blends were found to increase significantly with an increase in the percentage of TPU up to 20%, by retaining the tensile strength of PMMA. The effect of chemical aging on the performance of blends has been studied.
TL;DR: In this article, the structure and properties of the blend fibers were studied with the aids of infrared spectra (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM).
Abstract: Water‐soluble chitin (half‐deacetylated chitin) was prepared from chitosan by N‐acetylation with acetic anhydride. Alginate/water‐soluble chitin blend fibers were prepared by spinning their mixture solution through a viscose‐type spinneret into a coagulating bath containing aqueous CaCl2 and ethanol. The structure and properties of the blend fibers were studied with the aids of infrared spectra (IR), X‐ray diffraction (XRD) and scanning electron microscopy (SEM). structure analysis indicated good miscibility existed between alginate and water‐soluble chitin, due to the strong interaction from the intermolecular hydrogen bonds and electrostatic interactions. Best values for the dry tensile strength and breaking elongation were obtained when the water‐soluble chitin content was 30 wt%. The wet tensile strength and breaking elongation decreased with the increase of water‐soluble chitin content. The introduction of water‐soluble chitin in the blend fiber can improve the water‐retention properties of the blend...
TL;DR: Polymers containing pendant thymine groups undergo a 2π+2π cycloaddition crosslinking reaction, which results in photocrosslinking in thymine containing styrene derivatives.
Abstract: Polymers containing pendant thymine groups undergo a 2π+2π cycloaddition crosslinking reaction. The enzyme DNA photolyase has been demonstrated to reverse this photocrosslinking in thymine containing styrene derivatives.
TL;DR: In this paper, a ring-opening polymerization (ROP) was used to polymerize poly(ϵ‐caprolactone) with a thiophene end group.
Abstract: ϵ‐Caprolactone was polymerized by ring‐opening polymerization (ROP), using thiophene methanol as the initiator and stannous octoate as the catalyst to yield poly(ϵ‐caprolactone) with a thiophene end group. Homopolymerization of thiophene functionalized poly (ϵ‐caprolactone) (PCL) was achieved by a constant current electrolysis method. Copolymerizations of PCL with thiophene and pyrrole were achieved in acetonitrile (ACN)‐tetrabutylammonium tetrafluoroborate (TBAFB) solvent‐electrolyte couple via constant potential electrolysis. Characterization of the samples were performed by nuclear magnetic resonance spectroscopy (NMR), cyclic voltammetry (CV), fourier transform infrared spectroscopy (FT‐IR) and scanning electron microscopy (SEM). Electrical conductivities were measured by the four‐probe technique. Spectroelectrochemical behavior of PCL/PTh film, which was deposited on ITO‐glass, was investigated by UV‐Vis Spectrophotometer. Furthermore, it is found to be an anodically coloring copolymer that electroch...
TL;DR: In this article, a photoinitiator for the copolymerization of styrene and methylmethacrylate (MMA) was reported, and the kinetic data, inhibiting effect of benzoquinone and ESR studies indicate that the polymerization proceeds via a free radical mechanism.
Abstract: Curcumin (Cur), a natural colorant found in the roots of the Turmeric plant, has been reported for the first time as photoinitiator for the copolymerization of styrene (Sty) and methylmethacrylate (MMA). The kinetic data, inhibiting effect of benzoquinone and ESR studies indicate that the polymerization proceeds via a free radical mechanism. The system follows ideal kinetics (Rp α[Cur]0.5[Sty]0.97[MMA]1). The reactivity ratios calculated by using the Finemann–Ross and Kelen‐Tudos models were r1(MMA)=0.46 and r2(Sty)=0.52. IR and NMR analysis confirmed the structure of the copolymer. NMR spectrum showing methoxy protons as three distinct groups of resonance between 2.2–3.75 δ and phenyl protons of styrene at 6.8–7.1 δ confirmed the random nature of the copolymer. The mechanism for formation of radicals and random copolymer of styrene and MMA [Sty‐co‐MMA] is also discussed.
TL;DR: In this article, photo-oxidation of syndiotactic polypropylene-sPP/organoclay nanocomposites was performed by melting compounding of sPP, compatibilizer (iPP grafted with maleic anhydride), and organoclay filler ME C18 (modified with octadecyl ammonium chains in intergaleries of layered silicate, of which silicate layers (about 1 nm thin) were exfoliated).
Abstract: Photo‐oxidation of syndiotactic polypropylene–sPP/organoclay nanocomposites was performed. Nanocomposites were prepared in situ by melt compounding of sPP, compatibilizer (iPP grafted with maleic anhydride–iPP‐g‐MAN) and organoclay filler ME C18 (modified with octadecyl ammonium chains in intergaleries of layered silicate, of which silicate layers (about 1 nm thin) were exfoliated). The influence of ME C18 nanoparticles alone (in content region 1 to 15 wt%) and together with compatibilizer iPP‐g‐MAN on the photostability of the sPP nanocomposite was studied. It was found that the silicate ME C18 nanoparticles alone catalyze the photooxidation and shorten the induction period of photo‐oxidation to one fourth (at the content of 5 wt% of ME C18) in comparison with unfilled sPP) and the presence of compatibilizer supports the photo‐oxidation of sPP nanocomposite. The ME C18 nanoparticles decrease the efficiency of UV stabilizers. The rate of photo‐oxidation of sPP/clay nanocomposite after the induction period...
TL;DR: Oligocatechins synthesized exhibit enhanced anti‐tumorigenic activity to human colon cancer cells as compared with the monomeric catechins.
Abstract: Catechins are polyphenolic compounds found in green tea. These flavonoids possess anti‐oxidant, anti‐carcinogenic, and anti‐inflammatory properties. The primary goal of this work is to synthesize water‐soluble oligomers of catechins. Although, oxidative polymerization of catechins catalyzed by enzymes such as Horseradish Peroxidase (HRP) have been reported, the polymeric products have limited solubility. This restricts their compatibility with biological systems and their effectiveness as antioxidants or anti‐carcinogenic agents. Here we report a unique enzymatic approach for the synthesis of water‐soluble oligo(catechins). Polyelectrolytes such as Sulfonated Polystyrene (SPS) and surfactants such as sodium dodecylbenzenesulphonate (SDS) have been used as templates for the HRP catalyzed polymerization of (+)‐, (−)‐catechins and (−)‐epicatechin. Oligocatechins synthesized exhibit enhanced anti‐tumorigenic activity to human colon cancer cells as compared with the monomeric catechins.
TL;DR: In this article, it was shown that linear chains having one pyridinium ion and one CO2 ion as endgroups are the main reaction products for polylactone polymerization.
Abstract: When pyridine, 4‐methylpyridine (4‐MP) and 4‐(N,N‐dimethylamino)pyridine (DMAP) were used as initiators for the polymerization of pivalolactone in N‐methylpyrrolidone, linear chains having one pyridinium ion and one CO2 ⊖ ion as endgroups were found to be the main reaction products. The absence of cyclic oligolactones, even at temperatures up to 140°C, proves that the chain growth of the zwitterionic chains proceeds exclusively by anionic ring‐opening polymerization. When dichloromethane was used as a reaction medium, part of the polylactone chains had –CO2CH2Cl endgroups due to side reactions with the solvent. With diazabicyclooctane as initiator, a clean zwitterionic polymerization was found in NMP. With triethylamine or 2‐ethyloxazolidine as initiators, the zwitterionic/anionic ring‐opening polymerization was again the prevailing process, but significant side reactions also took place. In the case of 2‐ethyloxazolidine, these side reactions included the formation of cyclic oligolactones. In the case of...
TL;DR: In this paper, Dehydrated castor oil epoxy (DCOE), a product from a sustainable resource, has been chosen to improve upon the physical and mechanical properties of poly(methacrylic acid) through solution blending.
Abstract: Blending is a useful technique to improve upon the physico‐mechanical properties of the polymers. Synergies of the properties of the two polymers occur best when they are miscible or compatible with each other. Vegetable oil epoxy can be used for blending with polymers to improve upon their physical and mechanical properties. Poly(methacrylic acid) (PMAA) is a hard, brittle and water sensitive material. Dehydrated castor oil epoxy (DCOE), a product from a sustainable resource, has been chosen to improve upon the physical and mechanical properties of PMAA through solution blending. Blends of DCOE/PMAA were prepared in the weight ratios 80/20, 60/40 and 20/80 through a solution method by mixing in dimethyl sulphoxide. In the first instance, the miscibility of the two components was investigated using the techniques of viscosity and ultrasonic measurements. The study revealed that the two components showed semicompatibility/semimiscibility in solution. The compatibility in the solid phase was examined by dif...
TL;DR: In this article, the effect of hydrophilic block, PEG length, linker, concentration and temperature on nano micellar structures and interactions by static light scattering techniques was studied.
Abstract: The formation of micelles in a solvent that is selective for one of the blocks is one of the most important and useful properties of block copolymers. Recently, we have synthesized copolymers of polyethylene glycol and various dimethyl esters, which self‐assemble into nano micellar aggregates in aqueous media. These nano micelles are very effective in solubilizing otherwise insoluble drugs. The structure, interaction and size of these nano micelles are very important and critical to design an efficient drug delivery system. In the present work, we have studied the effect of hydrophilic block, PEG length, linker, concentration and temperature on these nano micellar structures and interactions by static light scattering techniques.
TL;DR: In this article, the effect of tetrafunctional peroxide initiators on free radical polymerization of various monomer systems including styrene, methyl methacrylate (MMA), styrene-MMA and α-methyl styrene with a tetra functional peroxide (JWEB50) initiator was investigated.
Abstract: An investigation into the effect of initiator functionality on the free radical polymerization of various monomer systems including styrene, methyl methacrylate (MMA), styrene–MMA and α‐methyl styrene–MMA with a tetrafunctional peroxide initiator (JWEB50) was completed. The performance of the tetrafunctional initiator was compared to a monofunctional counterpart (TBEC). Kinetic results showed that regardless of the monomer system studied, JWEB50 produced a faster rate of polymerization compared to TBEC at an equivalent concentration. Molecular weights, radii of gyration and intrinsic viscosities were obtained from two size exclusion chromatography setups: one equipped with a multi‐angle laser light scattering detector and the other with low‐angle laser light scattering and viscosity detectors. For the homopolymerization of styrene, JWEB50 produced polymer molecular weights similar to TBEC at the same concentration, while experiments with MMA indicated that JWEB50 produced molecular weights closer to those...
TL;DR: In this paper, the synthesis and characterization of two new calixarene-based Schiff bases and their polymeric resins are described. But they do not show selectivity toward transition metal cations, and a particularly high selectivity to Hg2+ and Pb2+.
Abstract: This article describes the synthesis and characterization of two new calix[4]arene Schiff bases and their polymeric resins. The extraction properties of these “proton switchable extractants” with alkali, transition, post transition metal cations and for dichromate anions are reported. The two new calix[4]arene based Schiff bases (5 and 6) have been synthesized from 5,17‐diformyl‐25,27‐dipropoxy‐26,28‐dihydroxycalix[4]arene (4) by treatment with 3‐amino‐methylpyridine and 1,8‐diaminooctane in two separate reaction flasks following the same procedure. Compounds 5 and 6 have been appended to a polymeric resin by treatment with Merrifield resin through a nucleophilic substitution reaction. The receptor compounds (3 and 5–8) do not extract alkali metal cations, but show some selectivity toward transition metal cations, and a particularly high selectivity to Hg2+ and Pb2+. The protonated forms of all of the calixarene‐based receptors are good extractants for transferring Cr2O7 2−/HCr2O7 − anions from an aqueous...
TL;DR: In this paper, star-shaped block copolymers made of poly(ϵ‐caprolactone) (PCL) and polystyrene (PS) were synthesized by combining ring-opening polymerization (ROP) of ϵ-caprolactorone and atom transfer radical polymerization(ATRP) of styrene (St).
Abstract: Newly designed star‐shaped block copolymers made of poly(ϵ‐caprolactone) (PCL) and polystyrene (PS) were synthesized by combining ring‐opening polymerization (ROP) of ϵ‐caprolactone (CL) and atom transfer radical polymerization (ATRP) of styrene (St). The switch from the first to the second mechanism was obtained by selective transformation of “living” radical sites. First, tri‐ and tetrafunctional initiators were used as an initiator for the “living” ring opening polymerization (ROP) of ϵ‐caprolactone producing a hydroxyl terminated three or four arm star‐shaped polymer. Next, the OH end groups of PCL star branches were derivatized into 2‐bromoisobutyrate groups which gave rise to the corresponding tri‐ and tetrabromoester ended‐PCL stars; the latter served as macroinitiators for the ATRP of styrene at 110°C in the presence of CuBr/2,2‐bipyridine (Bipy) catalyst system affording star‐shaped block copolymers PCLn‐b‐PSn (n=3 or 4). The samples obtained were characterizated by 1H‐NMR spectroscopy and GPC (g...
TL;DR: In this paper, the structure and composition of copolymers for a wide range of monomer feed were determined by elemental analysis (content of N for VIM−units) and by Fourier transform infrared spectroscopy through recorded analytical absorption bands for Ninylimidazole (VIM) and PAMA (1730 cm−1 for C˭O of ester group) units, respectively.
Abstract: N‐vinylimidazole (VIM), and phenacyl methacrylate (PAMA) copolymerized with different feed ratios using 1,4‐dioxane as a solvent and α,α'‐azobisisobutyronitrile (AIBN) as an initiator at 60°C. Structure and composition of copolymers for a wide range of monomer feed were determined by elemental analysis (content of N for VIM‐units) and by Fourier transform infrared spectroscopy through recorded analytical absorption bands for VIM (670 cm−1 for C‐N of imidazole ring) and PAMA (1730 cm−1 for C˭O of ester group) units, respectively. Monomer reactivity ratios for VIM (M1)‐PAMA (M2) pair were determined by the application of conventional linearization methods such as Fineman‐Ross (F‐R) and Kelen‐Tudos (KT) and a nonlinear error invariable model method using a computer program RREVM. The molecular weights (w and n) and polydispersity indices of the polymers were determined using gel permeation chromatography (GPC). Thermal behaviors of copolymers with various compositions were investigated by differential scanni...
TL;DR: In this paper, copolymers of styrene-maleic anhydride, SMA, and α-olefins were characterized by gel permeation chromatography, viscosity measurements, FT-IR, differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA).
Abstract: Copolymers of styrene‐maleic anhydride, SMA, and maleic anhydride‐α‐olefins (1‐hexene, 1‐octene, 1‐decene, 1‐dodecene, 1‐tetradecene and 1‐hexadecene) have been synthesized by free radical polymerization, using azobisisobutironitrile and benzoyl peroxide as initiators. Copolymers were characterized by gel permeation chromatography, viscosity measurements, FT‐IR, differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA). The copolymers of maleic anhydride‐α‐olefins exhibit a monomodal molecular weight distribution. During the TGA analysis, decomposition of maleic anhydride and α‐olefins was observed by FT‐IR. Carboxylic acids and gaseous CO2 were identified as decomposition products of the copolymers close to 200°C. The SMA copolymer was esterified with 2‐propanol, sec‐butanol and tert‐butanol at 65°C using 4‐dimethylaminopyridine catalyst and tetrahydrofurane solvent. The rate of reaction and limiting ester yields are lower than those obtained in the esterification with primary alcohols.
TL;DR: In this paper, a tartaric acid modified fatty amide diol (TAFA) was synthesized through condensation polymerization of N,N−bis(2−hydroxy ethyl) linseed oil fatty amides and tartarsic acid (TA) and was found to cure at room temperature.
Abstract: A novel tartaric acid modified fatty amide diol (TAFA) was synthesized through the condensation polymerization of N,N‐bis(2‐hydroxy ethyl) linseed oil fatty amide and tartaric acid (TA).The structural elucidation of the TAFA resin was carried out by FT‐IR,1H‐NMR, and 13C‐NMR spectroscopic techniques. The physico‐mechanical and physico‐chemical characterization of the resin were done by standard methods. TAFA, when further reacted with butylated melamine formaldehyde (BMF) in different phr (part per hundred part of resin) (TAFA‐BMF) was found to cure at room temperature. The TAFA‐BMF cured system was subjected to spectroscopic analysis to ascertain the structure and curing scheme of the same. The thermal studies of these resins were carried out by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The physico‐mechanical properties and anticorrosive performance of TAFA‐BMF coatings were evaluated by standard methods. The effect of TA and BMF on thermal stability, physico‐mechanica...
TL;DR: In this paper, a series of electron-transfer photosensitizers covalently bound to cationically polymerizable epoxy groups through siloxane spacer moieties were prepared.
Abstract: A series of electron‐transfer photosensitizers covalently bound to cationically polymerizable epoxy groups through siloxane spacer moieties were prepared. Novel synthetic methodology was employed for the preparation of these compounds that involves conducting a regioselective hydrosilation reaction at one end of a α, ω‐difunctional Si–H terminated siloxane to introduce an epoxide group. Thereafter, the resulting adduct is further reacted with an electron‐transfer photosensitizer, such as N‐vinyl carbazole or N‐allyl carbazole (ACZ) or 9‐vinyl anthracene, to produce the monomer‐bound photosensitizer. Using this method, three monomer‐bound photosensitizers were prepared. Ring‐opening photopolymerizations of the monomer‐bound photosensitizers were carried out to generate polymer‐bound photosensitizers. The reactivities of both the monomer‐ and polymer‐bound photosensitizers were investigated in various ring‐opening cationic photopolymerizations using Fourier transform real‐time infrared (FT‐RTIR) spectroscop...
TL;DR: In this paper, (sodium alginate (NaAlg)/acrylamide (AAm)) interpenetrating polymer networks (IPN) have been prepared at three different compositions, where the sodium alginates composition varies 1, 2, and 3% in 50% (w/v) acrylamides solutions.
Abstract: In this study, (sodium alginate (NaAlg)/acrylamide (AAm)) interpenetrating polymer networks (IPN) have been prepared at three different compositions, where the sodium alginate composition varies 1, 2, and 3% (w/v) in 50% (w/v) acrylamide solutions. These solutions have been irradiated with a 60Co‐γ source at different doses. The percent conversion was determined gravimetrically and 100% gelation was achieved at the 10.0 kGy dose. The swelling results at pH 7.0 and 9.0 indicated that (NaAlg/AAm)3IPN hydrogel, containing 3% NaAlg showed maximum % swelling in water, with swelling increasing in the order of Ni2+>Cd2+>Pb2+. Diffusion in aqueous solutions of metal ions within (NaAlg/AAm)IPN hydrogels was found to be Fickian character. Diffusion coefficients of (NaAlg/AAm)IPN hydrogels in water and aqueous solutions of metal ions were calculated. The maximum weight loss temperature and half life temperature for NaAlg, PAAm, (NaAlg/AAm)IPN and (NaAlg/AAm)IPN‐metal ion systems were found from thermal analysis stud...
TL;DR: In this paper, Nethylaniline and 2-Butanone oxime-blocked isocyanate prepolymers were prepared and their reaction with pyromellitic dianhydride (PMDA) was studied with a view to understand the effect of different parameters like solvents, temperature, blocking agents and deblocking catalysts [diazabicyclo 2.2.2 octane, DABCO] on the poly(urethane-imide) formation reaction.
Abstract: N‐Methylaniline‐ and 2‐Butanone oxime‐blocked isocyanate prepolymers were prepared and their reaction with pyromellitic dianhydride (PMDA) was studied with a view to understand the effect of different parameters like solvents, temperature, blocking agents and deblocking catalysts [diazabicyclo 2.2.2 octane, (DABCO) and dibutyltin dilaurate, (DBTDL)] on the poly(urethane‐imide) formation reaction. The reactions were followed by the carbon dioxide evolved during the imidization reaction. The effect of each individual parameter was studied with the reaction time and GPC data. It was found that the reactions proceeded at a faster rate in hexamethyl phosphoric acid triamide (HMPA), a solvent having basic nitrogens, than in mesitylene. Also, in HMPA, it was found that the molecular weights (Mw) of the polymers increased with an increase in temperature up to 125°C and then decreased, whereas in mesitylene, it was found that there was no appreciable change in molecular weight up to 150°C. Of the two blocked isocy...
TL;DR: In this article, the emulsion polymerization of styrene, activated by microwave irradiation and conductive heating, was modeled using the Predici® simulation package of CiT Microwave activated initiation.
Abstract: The emulsion polymerization of styrene, activated by microwave irradiation and conductive heating, was modeled using the Predici® simulation package of CiT Microwave activated initiation was modeled as adding a second conventional free‐radical chemical initiator, whose concentration is given by the intensity of microwave irradiation, and its “decomposition” kinetic rate constant is related to the ratio of monomer concentration to the rate of absorbed radiation Most of the kinetic rate constants and model parameters used in the model were taken from the literature, in order to avoid unnecessary parameter estimation procedures Model predictions of conversion, number and weight average molecular weights, for microwave and thermally activated systems, agree well with the experimental data reported in the literature, including experimental data previously reported by our own group