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The spectroscopic properties of poly (styrene-co-p-vinylbenzyl chloride) (poly (St-co-VBC)) were investigated by Fourier transform infrared spectroscopy and *H nuclear magnetic resonance spectroscopic techniques. The molecular geometry and vibrational frequencies of macroinitiator, poly (St-co-VBC), were calculated by using density functional theory (DFT) and Hartree-Fock (HF) methods with 6-31 G+ (d, p) as a basis set. Calculated theoretical values are shown to be in good agreement with that of experimental values. An excellent harmony between the two data sets was verified. Besides, the experimental data of macroinitiator were compared with experimental data of its corresponding monomers such as St and VBC. The dimer and trimer forms of macroinitiator are used as significant contributions for getting an accurate interpretation of the experimental frequencies of poly (St-co-VBC). The results revealed that the change from St and VBC to poly (St-co-VBC) should be characterized by the disappearance of the C[H.sub.2]=CH bonds of the vinyl group and the appearance of the aliphatic C-H and C[H.sub.2] bonds. The geometrical parameters, Mulliken atomic charges and frontier molecular orbitals energies were also calculated using the same theoretical methods. The chemical shifts were calculated by using the gauge-including atomic orbital method and all the theoretically predicted values were shown to be in good agreement with experimental values. Molecular orbital properties, molecular electrostatic potential, and the potential energy surface for the atom transfer radical polymerization (ATRP) of the macroinitiator were studied with DFT and HF calculations. The potential energy surface of the ATRP initiator is decided by their electronic effect and steric hindrance effect simultaneously. Key words: styrene, p-vinylbenzyl chloride (VBC), macroinitiator, vibrational spectra, DFT, MEP, FMOs, ATRP. Nous etudions les proprietes spectroscopiques du poly (p-chlorure de venylbenzyl-co-styrene) (poly (St-co-VBC)) a l'aide des techniques de spectroscopie infrarouge a transformee de Fourier et de spectroscopie de RMN sur 1H. La geometrie moleculaire et les frequences vibrationnelles du macro-amorceur poly (St-co-VBC) sont calculees a partir des methodes de la fonctionnelle de densite (MFD) et de Hartree-Fock (HF) dans un espace de base 6-31G+ (d, p). Les valeurs calculees sont en bon accord avec les valeurs experimentales. Nous constatons une excellente harmonie entre les deux. De plus, nous comparons les valeurs experimentales du macro-amorceur avec les valeurs experimentales de ses monomeres, St et VBC. Les formes dimere et trimere du macro-amorceur contribuent significativement a une description precise des frequences experimentales du poly (St-co- VBC). Les resultats montrent que le changement de St et VBO a poly (St-co-VBC) apparait etre caracterise par la disparition des liens C[H.sub.2]=CH du groupe vinyle et l'apparition des liens aliphatiques C-H et C[H.sub.2]. Les parametres geometriques, les charges atomiques de Mulliken et les energies FMO sont calcules par les memes methodes theoriques. Les deplacements chimiques sont calcules en utilisant la methode des orbitales atomiques incluant les effets de jauge et nous montrons que toutes les valeurs theoriques sont en bon accord avec les valeurs experimentales. De plus, les proprietes des orbitales moleculaires, le potentiel electrostatique moleculaire et l'analyse des surfaces d'energie potentielle pour l'ATRP du macro-amorceur sont etudies par calculs MFD et HF et la surface d'energie potentielle de l'amorceur ATFP est fixee simultanement par leur effet electronique et leur encombrement sterique. [Traduit par la Redaction] Mots-cles : styrene, p-chlorure de venylbenzyl (VBC), macro-amorceur, spectres de vibration, DFT, MEP, FMOs, ATRP. PACS Nos.: 31.15.A, 31.15.ae, 31.15.at, 31.15.E-, 33.20.Tp., 1. Introduction Polymerization reactions involving a macroinitiator have aroused great interest because of the wide possibilities for the preparation of new polymeric materials. A popular and important controlled radical polymerization [...]

Over the last century, adhesive use has become increasingly popular over other assembly methods for structural design. To meet the demands of the latest product designs and manufacturing processes, new [...]

In this study, we propose an efficient method for preparation of large scale, monodisperse poly(methyl methacrylate-co-butyl acrylate) latexes by application of the low power ultrasound irradiation. The effect of polymerization temperature and initiator concentration on the polymerization nature, particle size, and particle size distribution were investigated. Results indicated that the ultrasound pulses in the first minutes of polymerization increase instant free radical to monomer ratio as well mixing efficiency which led to higher monomer conversion, improved polymerization rate (especially at first 15 min of the reaction), and remarkable decrease in molecular weight distribution. Transmittance electron microscopy (TEM) and dynamic light scattering (DLS) revealed that the particle size and particle size distribution were significantly affected, particle size decreased, and more uniform particles were obtained. Dynamic mechanical thermal analysis also showed that the initiator concentration affected glass transition temperature ([T.sub.g]) of the final copolymers and in the case of ultrasound-assisted emulsion polymerization [T.sub.g] was in a very good agreement with theoretical predictions for copolymerization. POLYM. ENG. SCI., 56:214-221, 2016. [C] 2015 Society of Plastics Engineers, INTRODUCTION Emulsion polymerization is a scientifically, technologically, and commercially important polymerization method. High molecular weight polymers can be produced at fast polymerization rates. The continuous water phase is an excellent [...]

Sluggish and narrow process window of phthalonitrile resin has tremendously limited their wide applications. In this work, a novel phthalonitrile containing benzoxazine (4,4'-(((propane-2,2-diylbis (2H-benzo [e] [1,3]oxazine-6,3 (4H)-diyl) bis(3,1-phenylene))bis(oxy)) diphthalonitrile, BAph) with ortho-diallyl bisphenol A (DABPA) was investigated. The processing window of the BA-ph/DABPA blends were found from 50°C to 185°C, which was significantly broader than that of the pure BA-ph (120-200°C). The composites were prepared through a curing process involving sequential polymerization of allyl moieties, ring-opening polymerization of oxazine rings and ring-forming polymerization of nitrile groups. BA-ph/DABPA/GF(glass fiber) composite laminates were prepared in this study, and the composite laminate with BA-ph/DABPA molar ratio of 212 showed an outstanding flexural strength and modulus of 560 MPa and 37 GPa, respectively, as well as a superior thermal and thermo-oxidative stability up to 408 and 410°C. These outstanding properties suggest that the BA-ph/DABPA/GF composites are suitable candidates as matrices for high performance composites. POLYM. ENG. SCI., 56:150-157, 2016. [C] 2015 Society of Plastics Engineers, INTRODUCTION Phthalonitrile-based resins have drawn major attention in recent years due to their outstanding performance and potential applications in the field for aerospace, marine, and electronic applications [1-4]. Among them, [...]

Abstract Styrene-acrylic copolymer latexes were synthesized by emulsion polymerization process using sodium formaldehyde sulphoxylate (SFS) and tertbutyl hydroperoxide (TBHP) as redox initiators. Approximately 100% conversion was achieved successfully at 50[degrees]C. [...]

Phenolic foam (PF) displays excellent flame, smoke, and toxicity (FST) properties and good insulation properties. Nevertheless, the friability and inferior mechanical properties of PF have critically restricted its application in many fields. A series of phenolic foam/silica nanocomposites (MPF) with different silica contents were synthesized by in situ polymerization in this study. During the in situ polymerization process, the synthesis of phenolic resin/silica nanocomposites and formation of chemical bonding between the components were generated simultaneously. The reactive principle between silica nanoparticles and prepolymer was investigated using Fourier transform infrared spectroscopy (FTIR), and the results of FTIR indicated existence of the chemical reaction between them. Meanwhile, silica can act as 'bridge' to form cross-linked network structure. The mechanical, thermal, and friability properties of MPF nanocomposites were characterized. Moreover, the results of microstructure of pure PF and MPFs indicated that the cell size distributions of MPFs are narrower, the cell distributions of MPFs are more uniform, and the cell wall thickness of MPFs is thicker, compared with pure PF. When the content of silica sol was 2 wt%, the compressive strength, compressive modulus, and tensile strength were increased by a factor of 47.37%, 38.55%, and 57.14% compared with that of pure PF, respectively. Furthermore, all MPF nanocomposites exhibited better thermal stability and lower pulverization ratio than that of pure PF., INTRODUCTION High-rise fires have been attracted increasing attention in recent years due to the flammability of polymer foam insulation materials [1]. As one of thermal insulation materials [2-4], polymer foam [...]

In the present study, PS@α-[Fe.sub.2][O.sub.3] nanocomposites were prepared by chemical microemulsion polymerization approach and the ability of magnetic beads to remove Cu(II) ions from aqueous solutions in a batch media was investigated. Various physico-chemical parameters such as pH, initial metal ion concentration, temperature, and equilibrium contact time were also studied. Adsorption mechanism of [Cu.sup.2+] ions onto magnetic polymeric adsorbents has been investigated using Langmuir, Freundlich, Sips and Redlich-Petersen isotherms. The results demonstrated that the PS@α-[Fe.sub.2][O.sub.3] nanocomposite is an effective adsorbent for [Cu.sup.2+] ions removal. The Sips adsorption isotherm model ([R.sup.2] > 0.99) was more in consistence with the adsorption isotherm data of Cu(II) ions compared to other models and the maximum adsorbed amount of copper was 34.25 mg/g. The adsorption kinetics well fitted to a pseudo second-order kinetic model. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) were calculated from the temperature dependent sorption isotherms, and the results suggested that copper adsorption was a spontaneous and exothermic process., INTRODUCTION Nowadays, environmental pollution caused by heavy metals has been considered a major problem and has continuously been the focus of worldwide attention [1], Heavy metals with adverse health effects [...]

Many pouches or bags for dry goods, like cereal and crackers, are difficult to peel apart without tearing and damaging the bag. Consumer Reports magazine rated cereal bags as one [...]

An interpenetrating polymer network (IPN) based on the sodium alginate (A) and partially neutralized poly(methacrylic acid) (MAA) was prepared by free radical polymerization followed by additional cross-linking of sodium alginate with calcium ions. Obtained material (A/MAA IPN) was characterized by FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy, and rheological measurements. Swelling behavior of synthetized IPN has been also investigated. Ti[O.sub.2] nanoparticles (Ti[O.sub.2] NPs) were immobilized onto A/MAA IPN by dip-coating method and obtained Ti[O.sub.2]/IPN nanocomposite was used for removal of the methylene blue (MB) from aqueous solution. The photodegradation (under illumination) and sorption (in the dark) processes for dye removal were monitored through decrease of dye concentration in the solution by UV/VIS spectrometer. The Ti[O.sub.2]/IPN nanocomposite sorbed approximately 93% of the MB from a 10 mg [L.sup.-1] MB solution in the dark, but no degradation occurred. Likewise, more than 93% of dye was removed after 8 h of illumination. However, after 24 h of illumination, the samples were discolored indicating that dye molecules were successfully degraded. Thus, the Ti[O.sub.2]/IPN nanocomposite could be utilized in the photodegradation-sorption process for the abatement of pollutants in water., INTRODUCTION Hydrogels are a water-swollen, and cross-linked polymeric networks produced by simple reaction of one or more monomers [1, 2]. Interpenetrating network type hydrogel (IPN) is formed by interpenetration of [...]

An exfoliated clay-polymer nanocomposite was prepared by surface-initiated ring opening metathesis polymerization (SI-ROMP) of norbornene on a montmorillonite (MMT) clay with a modified surface. Utilizing the hydrothermalsilylation reaction between a norbornenyl-bearing chlorosilane agent and silanol groups of the MMT clay, we were able to bind a metal alkylidene catalyst to the surface in order to grow poly(norbornene) chains directly from the surface using ROMP. Our approach produced nanocomposites having poly(norbornene) chains that are covalently attached to the inorganic substrate, as opposed to most conventional polymer-clay composites that have ionically tethered chains (via the ammonium-based modifiers of the organoclay) or physically adsorbed polymers., INTRODUCTION Clay-based polymer nanocomposites are a class of inorganic-organic hybrids where the polymer matrix is reinforced with a small loading of nanometric-sized clay platelets [1-5]. Increased mechanical properties [6-8], higher [...]

Hybrid composite of polyaniline metal oxide composite, polyaniline-dodecyl hydrogen sulfate salt with ferric oxide, was prepared for the first time via simple one-step process of oxidizing aniline with ferric tris(dodecyl sulfate). Ferric tris(dodecyl sulfate) acts as an oxidant, emulsifier, dopant for polyaniline and also source of ferric oxide. Polyaniline salt composites were prepared via aqueous, emulsion, and interfacial polymerization pathways. Polyaniline salt composite was successfully demonstrated as polymer based solid acid catalysts in the ring-opening polymerization of ζ-caprolactone for the first time. This methodology gave low molecular weight poly(ζ-caprolactone) (MW-4035) with highly crystalline polymer of flower petals like morphology in 52 wt% yield (with respect to the amount of ζ-caprolactone used). Advantages of this methodology are the use of easily synthesizable, easily handlable, recyclable, cheaper, and eco-friendly nature of the catalyst., INTRODUCTION In the large field of nanotechnology, conducting polymer matrix based metal oxide nano composites have become a prominent area of current research and development. Composite materials are especially important [...]

Transarterial vascular embolization and chemoembolization has become common medical procedures, where partially hydrolyzed poly(vinyl alcohol) (PVA) beads remains as one of the most used embolic agent materials. Although synthetic, PVA cannot be synthesized by direct polymerization and must be obtained by chemical modification of another polymer, usually poly(vinyl acetate) (PVAc). The aim of the present work is to synthesize spherical core-shell PVAc/PVA particles and study the morphological and molecular modifications during shell formation. The polymer particles where produced in two stages, where first the PVAc core was obtained by suspension polymerization of vinyl acetate (VAc) and then the PVA shell synthesized through hydrolysis. Spherical PVAc particles were successfully produced and isolated using an optimized suspension polymerization process. During the shell formation, it was shown that none of the conditions used affected the overall morphology of the particles although changes in the final size distribution could be observed. However, it was possible to identify the process variables and reaction condition that affect the molecular weight averages and polydispersities of the final copolymer., INTRODUCTION Polymer materials find widespread use in several fields, including many medical practices, as polymer products can be used as excipient of pharmaceutical formulations, embolic device in transarterial vascular embolization [...]

Diffusional limitations (the gel, glass, and cage effects) are manifested in several bulk free radical homopolymerizations as well as in random copolymerizations. These are associated with decreases of several orders of magnitude of the rate constants of termination, propagation, and initiation (the initiator efficiency), respectively. These phenomena have been modeled earlier using the free volume theory for the diffusivities of primary radicals, macro-radicals, and monomer molecules, and have been applied to homopolymerizations. In this study, a similar model is developed for random bulk copolymerizations. The parameters of the model are fitted using isothermal data on styrene acrylonitrile random copolymerization carried out in small ampoules. Thereafter, best-fit global correlations have been developed for this system. This enables the model to be used for studying non-isothermal copolymerizations, as well as for carrying out optimization of industrial reactors, where non-isothermal conditions are a norm., INTRODUCTION Styrene-acrylonitrile (SAN) random copolymer is a rigid and transparent plastic material which is produced by the copolymerization of styrene and acrylonitrile in the presence of freeradical generating initiators like [...]

In this work, a chitosan sample with a high degree of deacetylation (DD >95%) obtained from freshwater shrimp shells was subjected to drying processes in an electric oven and by supercritical C[O.sub.2]. The results indicated that drying chitosan particles with supercritical C[O.sub.2] resulted in a very significant increase in specific surface area and pore volume, and also increased the material's crystallinity index. This drying route led to a more than 10-fold reduction in viscosimetric molecular weight (from 35.3 to 3.0 kDa), indicating that the physical drying process caused the chitosan to depolymerize, which usually occurs by enzymatic and chemical methods, according to the literature. Low molecular weight chitosan is essential for some applications in the field of biomedicine (drug delivery for example); hence, drying via the C[O.sub.2] route can be considered a promising technique for the production of high value-added materials with applications in this area., INTRODUCTION The deacetylation of chitin--a polysaccharide occurring abundantly in nature and extracted commercially from fish industry waste, such as crab and shrimp shells, among other sources--yields chitosan. Chitosan is a [...]

Abstract Novel, partially bio-based poly(vinyl ether) copolymers derived from soybean oil and cyclohexyl vinyl ether (CHVE) were produced by cationic polymerization and investigated for application as alkyd-type surface coatings. Three [...]

Abstract High-density, non-thermal, glow-discharge atmospheric-pressure plasma was used for graft polymerization of a vapor deposited fluorocarbon mixture of 1,1,2,2-tetrahydroperfluorodecyl acrylate and 1,1,2,2-tetrahydroperlluorododecyl acrylate on undyed cotton fabrics, which furnished a [...]

Protonated form of poly(sulfonic acid diphenyl aniline) (p-PSDA) was synthesized through oxidative chemical polymerization of sodium salt of diphenylamino-4-sulfonic acid in hydrochloric acid and then, its deprotonated form (PSDA) was obtained by neutralization with aqueous ammonium hydroxide solution. The samples were characterized by thermal analysis and Fourier Transform Infrared, Ultraviolet-visible, ¹H-NMR spectroscopy techniques. Their dispersive surface energies as well as surface acidity and basicity were determined by inverse gas chromatography at temperatures between 313 and 353 K. The dispersive surface energy of p-PSDA was found to be considerably lower but it increased with temperature while that of PSDA was close to those of conventional polymers and decreased slightly with temperature. According to the Schreiber's procedure, the surfaces of p-PSDA and PSDA were found to be acidic and amphoteric, respectively. It was observed from the electron microscope images p-PSDA chains can form self-organized circular polydisperse micro-sized aggregates in aqueous solutions while PSDA cannot self-organize to form individual aggregates., INTRODUCTION The intrinsically conducting polymers (ICP) have been used in the fields of conducting composites, conducting textiles, rechargeable batteries, corrosion protection of metals, ion exchange membranes, photovoltaics, memory devices, light [...]

Abstract A series of UV-curable isophorone diisocyanate-based poly(ester-urethane)methacrylate (IPEUMA) oligomers were synthesized by a two-step polymerization process. The amount of isophorone diisocyanate was varied during the synthesis. The effects of [...]

Abstract In this work, the application of hyperbranched polyglycerol as a performance additive for water-based printing inks is demonstrated. The hyperbranched polyglycerol, (BPG), was synthesized through anionic ring-opening polymerization from [...]

Endocytosis is required for internalization of micronutrients and turnover of membrane components. Endophilin has been assigned as a component of clathrin-mediated endocytosis. Here we show in mammalian cells that endophilin marks and controls a fast-acting tubulovesicular endocytic pathway that is independent of AP2 and clathrin, activated upon ligand binding to cargo receptors, inhibited by inhibitors of dynamin, Rac, phosphatidylinositol-3-OH kinase, PAK1 and actin polymerization, and activated upon Cdc42 inhibition. This pathway is prominent at the leading edges of cells where phosphatidylinositol-3,4-bisphosphate--produced by the dephosphorylation of phosphatidylinositol3,4,5- triphosphate by SHIP1 and SHIP2--recruits lamellipodin, which in turn engages endophilin. This pathway mediates the ligand-triggered uptake of several G-protein-coupled receptors such as [α.sub.2a]- and [β.sub.1]- adrenergic, dopaminergic D3 and D4 receptors and muscarinic acetylcholine receptor 4, the receptor tyrosine kinases EGFR, HGFR, VEGFR, PDGFR, NGFR and IGF1R, as well as interleukin-2receptor. We call this new endocytic route fast endophilin-mediated endocytosis (FEME)., The BAR (Bin/amphiphysin/Rvs)-domain-containing protein endophilin-A (hereafter called endophilin) is an endocytic protein that recruits dynamin and synaptojanin (1), and the disruption of which has a profound effect on endocytosis in [...]

Rod-like and spherical mesoporous SBA-15 silica particles were synthesized as pure silicas and surface modified by organosilane coupling agents firstly, and then the effects of these mesoporous materials on the critical micelle concentration (CMC) of sodium dodecylsulfate (SDS), the stabilities of batch and semi-continuous MMA emulsion polymerizations, and the molecular weights and molecular weight distributions of the polymer products were studied. The incorporation of both unmodified and silane-modified forms of the mesoporous silica particles in the polymerization reaction increased the CMC of SDS. The presence of the unmodified mesoporous silica in the polymerization process led to instability in the batch emulsion polymerization process, as indicated by the formation of increased amounts of coagulum, and a decrease in the molecular weight of the polymer product. However, in comparison to the polymer formed in the absence of particle additives the molecular weight of the PMMA polymer increased with the amount of emulsifier and the addition of silane-modified SBA-15 particles, suggesting the growth of the polymer chains is facilitated at least in part by reaction in the pores of the particles. The improvement in molecular weight indicates that semi-continuous MMA emulsion polymerization is best suited for the preparation of PMMA-mesoporous silica composites., INTRODUCTION Since the discovery of hexagonally ordered mesoporous molecular sieves silicas at the beginning of the 1990s, the synthesis and application of the advanced mesoporous materials have undergone rapid growth. [...]

Muscular dystrophies result from a defect in the linkage between the muscle fiber cytoskeleton and the basement membrane (BM). Congenital muscular dystrophy type MDC1A is caused by mutations in laminin [alpha]2 that either reduce its expression or impair its ability to polymerize within the muscle fiber BM. Defects in this BM lead to muscle fiber damage from the force of contraction. In this issue of the JCI, McKee and colleagues use a laminin polymerization-competent, designer chimeric BM protein in vivo to restore function of a polymerization-defective laminin, leading to normalized muscle structure and strength in a mouse model of MDC1A. Delivery of such a protein to patients could ameliorate many aspects of their disease., Many pathways to muscular dystrophy The mechanism whereby a contractile multinucleated skeletal muscle fiber is linked to the basement membrane (BM) that ensheaths it represents a paradigm for our understanding [...]