Polymer Chemistry

In the present study we examined the oxygen-transport properties of poly(ethylene naphthalate) (PEN) isothermally crystallized from the melt (melt crystallization) or quenched to the glass and subsequently isothermally crystallized by heating above the glass transition temperature (cold crystallization). The gauche/trans conformation of the glycol linkage was determined by infrared analysis, and the crystalline morphology was examined by atomic force microscopy (AFM). Explanation of the unexpectedly high solubility of crystallized PEN required a two-phase transport model consisting of an impermeable crystalline phase of constant density and a permeable amorphous phase of variable density. The resulting relationship between oxygen solubility and amorphous-phase density was consistent with free volume concepts of gas sorption. Morphological observations provided a structural model for solubility and permeability. The model consisted of a permeable amorphous matrix of constant density containing dispersed spherulites of lower permeability. The spherulites themselves were composites of impermeable crystallites and permeable interlamellar amorphous regions of lower density than the amorphous matrix. Dedensification of the interlamellar amorphous phase was due to the constrained nature of amorphous chains anchored to crystallites.

The dynamic mechanical and infrared spectroscopic investigation of ionomer blends of poly-(diacety1ene)-and polystyrene-based ionomers has shown that miscibility of this usually incompatible polymer pair can be achieved through ion-ion interactions between the blend components. Microphase separation is prevented through ionic contacts generated during the blend formation; a schematic model of mixing in the blends is proposed.

The structure of adsorption layers of amphiphilic block and block‐like copolymers of poly(isobornyl acrylate) and poly(acrylic acid) on the surface of hydrophilic titanium dioxide and hydrophobic copper phthalocyanine (CuPc) pigments in an aqueous dispersion has been studied by the electrokinetic sonic amplitude (ESA) method. The electroacoustic behaviour of the polyelectrolyte block copolymer‐coated particles could be described in the context of the polymer gel layer theory. The polymer layer around the particles was found to be much thinner for CuPc as compared to the TiO2 substrate. This is attributed to differences in the adsorption mechanism and the composition of the adsorption layer normal to the substrate surface. Adsorption models were established that consider effects of the copolymer structure.magnified image

Latex paints and coatings are colloidal suspensions, in which amorphous polymer particles are dispersed in an aqueous phase. The polymer-water interface plays a key role in the stability and rheology of the suspension. To obtain a molecular level view of this interface, atomistic simulations were performed for a slab of poly(methyl methacrylate)-poly(butyl acrylate) random copolymer in water, focusing on polymer and water density profiles, the hydrogen bonding of water with polymer carbonyl groups, and surface tension. The carbonyl groups at the interface were found to orient significantly towards water. We also calculated the temperature dependence of the surface tension between the polymer/water and polymer/ vacuum interfaces, including tail corrections for cut-off dispersion interactions, and we predict the contact angle of a water droplet at room temperature.

Therefore it becomes possible to synthesize hydrogels that can be used to immobilize a variety of compounds, such as drugs, proteins or even cells. During this work new polymers based on methacrylate monomers were prepared. Their characterization was accomplished by several techniques, e.g. Fourier Transform Infrared Spectroscopy (FTIR), swelling measurement, Differential Scanning Calorimetry (DSC) and evaluation of mechanical properties. Their subacute subcutaneous toxicity was also evaluated by using Wistar rats.

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Se describe la caracterización mediante técnicas espectroscópicas de una montmorillonita natural colectada en Cuencamé, Durango. La composición de las capas tetraédricas y octaédricas fue analizada por Resonancia Magnética Nuclear (RMN) de ángulo mágico para los núcleos de 29 Si y 27 Al. Las propiedades superfi ciales de la arcilla se cuantifi caron utilizando técnicas de adsorción-desorción de nitrógeno y mediante la aplicación de los métodos de Brunahuer-Emmett-Teller (BET) y Barrett-Joyner-Halenda (BJH). Los resultados indican que la arcilla analizada es una montmorillonita sódica con una capa molecular de agua adsorbida entre sus láminas, cuyos átomos de Si en la estructura de fi losilicato Q 3 presentan diferente composición Si-nAl (n = 0, 1 y 2). El 3.3% de los átomos de Al correspondientes a la estructura se encuentran sustituyendo a los de Si en la capa. La presencia de los iones paramagnéticos Fe +3 y Mn +2 en la montmorillonita fue determinada por resonancia paramagnética electrónica (RPE), después de ser tratada con HCl y CF 3 SO 3 H. Adicionalmente, se discuten los resultados adquiridos por las técnicas de absorción atómica, microscopía de barrido electrónico, infrarrojo y análisis térmico gravimétrico.

Polymerization of phenoxyethyl acrylate was induced without catalyst or initiators by the application of hydrostatic pressure at elevated temperature. Broadband dielectric and infrared spectroscopy were employed to follow the course of the reaction, which reached a degree of conversion of 60%. The structure of the obtained polymer was determined from density functional theory calculations.

This work is focused on the synthesis and characterisation of a range of branched polybutadiene materials using a combination of anionic polymerisation and post-polymerisation coupling reactions. The branched polymer architectures targeted included stars, H-shaped polymers and long-chain randomly branched polymers. Both three and four-arm star polymers were synthesised. The stars were characterised using both size exclusion chromatography (SEC) and interaction chromatography (IC) – in particular temperature gradient interaction chromatography (TGIC). TGIC was able to confirm structural dispersity within the crude and purified star polymers, which was otherwise undetectable by SEC. H-shaped polymers were synthesised using the “macromonomer” approach, which involves the use of polymers with reactive chain-end functionalities introduced via a functionalised protected initiator or a functionalised protected end capping agent. The functional macromonomers were then coupled together in a ...

The photochemical valence isomerization of the synthesized poly(ester)s (P-1-P-4, and P-5a-c) was examined in tetrahydrofuran solution or in the film state upon irradiation with a 500-W xenon lamp, and it was found that each photochemical reaction proceeded very smoothly. It was also observed that the rate of the photochemical reaction of the NBD polymers increased efficiently by the addition of 4,4 0 -bis-(diethylamino)benzophenone (BEBP) as a photo-sensitizer in the film state. The stored thermal energies of the irradiated polymers were evaluated by DSC analysis to be 75-153 J/g.

The photochemical valence isomerization of the synthesized poly(ester)s (P-1-P-4, and P-5a-c) was examined in tetrahydrofuran solution or in the film state upon irradiation with a 500-W xenon lamp, and it was found that each photochemical reaction proceeded very smoothly. It was also observed that the rate of the photochemical reaction of the NBD polymers increased efficiently by the addition of 4,4 0 -bis-(diethylamino)benzophenone (BEBP) as a photo-sensitizer in the film state. The stored thermal energies of the irradiated polymers were evaluated by DSC analysis to be 75-153 J/g.

New hole transport polymers were prepared by polyaddition of N, N'-diphenyl-N, N'-bis(4methylphenyll-1,4-phenylenediamine (PDA) with divinyl or diisopropenyl benzene and were characterized by 1 H NMR, differential scanning calorimetry (DSC), UV absorption spectra and cyclic voltammetry. These polymers exhibit high glass transition temperatures and low oxidation potentials. Two-layer electroluminescent (EL) devices, in which the polymers were spin cast on ITO anode as the hole transport layer and aluminum tris(8-hydroxyquinoline) (Alq) was used as the emitting layer, gave a high brightness of above 10000 cd m -2 with an operating voltage ofless than 15 V.

Copolymers are valuable supports for obtaining heterogeneous catalysts that allow their recycling and therefore substantial savings, particularly in the field of asymmetric catalysis. This contribution reports the use of two comonomers: Azido-3-propylmethacrylate (AZMA) bearing a reactive azide function was associated with 2-methoxyethyl methacrylate (MEMA), used as a spacer, for the ATRP synthesis of copolymers, and then post-functionalized with a propargyl chromium salen complex. The controlled homopolymerization of MEMA by ATRP was firstly described and proved to be more controlled in molar mass than that of AZMA for conversions up to 63%. The ATRP copolymerization of both monomers made it possible to control the molar masses and the composition, with nevertheless a slight increase in the dispersity (from 1.05 to 1.3) when the incorporation ratio of AZMA increased from 10 to 50 mol%. These copolymers were post-functionalized with chromium salen units by click chemistry and their ...

This invention describes a method for preparing water insoluble biocompatible gels, films and sponges by re acting hyaluronic acid, or a salt thereof, with a carbodi imide in the absence of a nucleophile or a polyanionic polysaccharide. The water-insoluble gels, films and sponges of this invention may be used as surgical aids to prevent adhesions of body tissues and as drug delivery vehicles.

The synthesis of novel block copolymers, namely poly(limonene-phthalate)-block-poly(pentadecalactone) and poly(limonene-phthalate)-block-poly(pentadecalactone) is here described. To achieve this synthesis, a bimetallic aluminum based complex (1) was used as catalyst in the combination of two distinct processes: the ring-opening polymerization (ROP) of macrolactones such as ω-pentadecalactone (PDL) and ω-6-hexadecenlactone (HDL) and the ring-opening copolymerization (ROCOP) of limonene oxide (LO) and phthalic anhydride (PA). The synthesis of di-block polyesters was performed in a one-pot procedure, where the semi-aromatic polyester block was firstly formed by ROCOP of LO and PA, followed by the polyethylene like portion produced by ROP of macrolactones (PDL or HDL). The obtained di-block semiaromatic polyesters were characterized by NMR and GPC. The structural organization was analyzed through XRD. Thermal properties were evaluated using differential thermal analysis (DSC) and thermo...

New magnesium complexes were used as catalysts for the ring opening polymerization of cyclic esters to produce degradable polymers. In the ROP of macrolactones, good activity and control were achieved at room temperature, conditions generally prohibitive for macrolactones.

Biodegradable block and random copolymers have attracted numerous research interests in different areas, due to their capability to provide a broad range of properties. In this paper, an efficient strategy has been reported for preparing biodegradable PCL-PLA copolymers with improved thermal, mechanical and rheological properties. Two block-copolymers are synthesized by sequential addition of the cyclic esters lactide (L-LA or D,L-LA) and ε-caprolactone (CL) in presence of a dimethyl(salicylaldiminato)aluminium compound. The random copolymer of L-LA and CL was synthetized by using the same catalyst. Chain structure, molar mass, thermal, rheological and mechanical properties are characterized by NMR, SEC, TGA, DSC, Rheometry and DMTA. Experimental results show that by changing the stereochemistry and monomer distribution of the copolymers it is possible to obtain a variety of properties. Promising shape-memory properties are also observed in the di-block copolymers characterized by t...

Degradable polymers based on α-hydroxy acids and α-amino acids constitutes a potent class of biomaterials, combining high hydrolyzability with structural features that mimics peptides. Driven by the design criteria to construct isolated α-amino acid units along a main polylactide chain, a copolymer system was developed based on two monomers with distinctly different equilibrium behaviors. This was uncovered by detailed understanding on the kinetic and thermodynamic polymerizability of 3S,6S-dimethylmorpholine-2,5-dione (DMMD) and Llactide (LLA) at low reaction temperatures. Under Brønsted base-promoted ring-opening copolymerization (ROCOP) conditions, the equilibrium nature of the copolymerization was shown susceptible to changes in the system, such as catalyst basicity, solvent polarity and initial monomer concentrations. Subsequently, high equilibrium conversions of both monomers with control over molecular weight and dispersity could be achieved within short reaction times by modulation of these factors. Thermodynamic elucidations of the copolymerization system revealed that DMMD behaved as an unstrained monomer with a large propagation barrier, favored by an increase in polymerization temperature. Ultimately, the high propagation barrier of DMMD in the system resulted in a kinetically controlled mechanism with the formation of completely isolated units of DMMD along the polylactide backbone. These results extend current ROCOP strategies of morpholine-2,5-diones and cyclic esters to a mild and selective copolymerization platform for the construction of sequence-controlled α-amino acid decorated polyesters for medical applications.

Linear aliphatic polyesters are degradable thermoplastic polymers, which can be obtained by ring-opening polymerization (ROP) of cyclic esters through a coordination-insertion mechanism. Aluminum based organometallic complexes have a leading position as efficient catalysts for this polymerization process. Aluminumalkyl complexes bearing salicylaldiminato ligands, although less explored, have been shown to be efficient and versatile catalysts for the ROP of various cyclic esters. These species have the potential to function as active catalysts in the ROP because of their less coordinatively saturated nature with respect to analogous SALEN-type complexes. They have been used as efficient catalysts in the ROP of commercially available cyclic esters, such as ε-caprolactone, L-lactide, rac-lactide, and glycolide. Moreover, they resulted in efficient catalysts for the ROP of cyclic esters with large ring-size and for the ROP of functionalized lactide. Furthermore, they have been used in the co-and ter-polymerization of various cyclic esters affording well controlled polymerization and a plethora of microstructural architectures, ranging from random to block to multiblock.

New fluorinated bis(phenoxy-imine)zirconium complexes bearing halogen substituents in the ortho and para positions of the phenolate rings, bis [N-(3,5-dibromosalycilidene)-2,3,4,5,6-pentafluoroaniline]-Zr(IV) dichloride (1) and bis[N-(3,5-dichlorosalycilidene)-2,3,4,5,6-pentafluoroaniline]-Zr(IV) dichloride (2) have been synthesized and used as precatalysts in the polymerization of propylene and 1-hexene. Their catalytic behaviour was compared with that of the analogous fluorinated zirconium complexes bearing alkyl groups in the same positions of the phenolate rings to investigate the effects produced by the introduction of additional electron-withdrawing halogen substituents. Complexes 1 and 2 produce stereoirregular, slightly syndiotactic enriched polypropylenes showing enhanced catalytic activities and an improved primary regioselectivity. Both catalysts promote efficiently the oligomerization of 1-hexene to atactic and regioregular oligomers. Interestingly for both the studied monomers it is possible to control the molecular weights and the structures of end groups of the produced polymeric chains by an appropriate choice of the cocatalyst. Functionalization reactions of the unsaturated polymeric chains selectively produced are also reported.

Neutral and bis-cationic palladium(II) complexes with 1,2-bis(di(2-methoxyphenyl)phosphino)ethane (o-MeO-dppe) and 1,3-bis(di(2methoxyphenyl)phosphino)propane (o-MeO-dppp) have been synthesized and employed to catalyze the CO-ethylene copolymerization reaction in either protic or aprotic solvents. A comparison of the catalytic performance of these complexes with that of analogous precursors stabilized by 1,2-bis(diphenylphosphino)ethane (dppe) and 1,3-bis(diphenylphosphino)propane (dppp) ligands has shown significant differences in terms of catalytic productivity and molecular weight. In situ and operando high-pressure NMR experiments have provided valuable information on catalysis resting states and intermediates and have contributed to rationalize the observed productivity as well.

Values of f(A) Calculated as a Function of Aperture and Pinhole Size 11g 5.2 Molecular Weight x 10"^a nd Polydispersity Index, ^j/^n 126 5.3 The Mark-Houwink Constants K" and a in [n] = K M for Na-copoly (ethyl acryl ate-acryl ic acid) in^V arious Media 127 5.4 a and 5 Values in the Relationship, <s^> = KM ^, for Na-copoly (ethyl acryl ate-acryl ic acid), in Various Media 14q 5.5 K and v Values in the Relationship, <s^> = KM^.^, for Na-copoly (ethyl acryl ate-acryl ic acid) in Various Media 141 5.6 Limiting Concentrations, C^,, for Na-copoly (ethyl acryl ate-acryl ic acid) in various Media 144 6.1 Values of D2 and k/ for Na-copoly (ethyl acryl ate-acryl ic acid) Fractions 179 6.2 Comparison of Values of b Obtained Experimentally from = and From the Relation 3b' = a + 1 ? . 204 6.3 Comparison of Experimental Values of k^^with Pre- dictions of Yamakawa, and Pyun and Fixman 220 xiv CHAPTER I the methods which have been used to observe the transition in Na-copoly (ethyl acrylate-acrylic acid). Chapter V describes the experimental methods used for the ex- periments. Chapter VI presents the results of the present study be- ginning with the important description of the data reduction and ending with the conclusions drawn from the data analysis.

All solid state composite electrolytes were prepared using fumed silica (SiO2) silanated with an oligomeric polyethylene oxide (PEO) silane containing 6-9 ethylene oxide repeat units, a PEO matrix and LiClO4 (8/1 O/Li). The PEO-silane covalently attached to the silica was amorphous, with a T(sub g) that increased from -90 C to -53 C after attachment. The conductivity of films prepared using the PEO-silanated silica increased to approx. 6 x 10(exp -5) S/cm at RT compared with approx. 1 x 10(-5) S/cm for films prepared with unsilanated SiO2.

Controlling morphology of polysiloxane blends crosslinked by the hydrosilylation reaction followed by pyrolysis constitutes a robust strategy to fabricate polymer-derived ceramics (PDCs) for a number of applications, from water purification to hydrogen storage. Herein, we introduce a dissipative particle dynamics (DPD) approach that captures the phase separation in binary and ternary polymer blends undergoing hydrosilylation. Linear polyhydromethylsiloxane (PHMS) chains are chosen as preceramic precursors and linear vinyl-terminated polydimethylsiloxane (v-PDMS) chains constitute the reactive sacrificial component. Hydrosilylation of carbon-carbon unsaturated double bonds results in the formation of carbon-silicon bonds and is widely utilized in the synthesis of organosilicons. We characterize the dynamics of binary PHMS/v-PDMS blends undergoing hydrosilylation and ternary blends in which a fraction of the reactive sacrificial component (v-PDMS) is replaced with the non-reactive sacrificial component (methyl-terminated PDMS (m-PDMS), polyacrylonitrile (PAN), or poly(methyl methacrylate) (PMMA)). Our results clearly demonstrate that the morphology of the sacrificial domains in the nanostructured polymer network formed can be tailored by tunning the composition, chemical nature, and the degree of polymerization of the sacrificial component. We also show that the addition of a non-reactive sacrificial component introduces facile means to control the self-assembly and morphology of these nanostructured materials by varying the fraction, degree of polymerization, or the chemical nature of this component.

Bu çalışmada [Ru4(p-cymene)4(μ2-NՈN)2(μ4-OOՈOO)2][CF3SO3)4] (NՈN = Bütilen-1,4-bisbenzimidazol (bbim)) genel formülüne sahip biyolojik aktif tetranükleer aren rutenyum kompleks bileşiği, Ru2(p-cymene)2 (μ4OOՈOO)Cl2 (OOՈOO = 5,8-dioxido-1,4-naphtoquinonato (donq))&#39;nun gümüş triflorometansülfonat ile reaksiyona sokulması, ardından karşılık gelen NՈN bağlayıcılarının eklenmesi ile hazırlanmıştır. Biyolojik aktif aren rutenyum bileşiği IR, UV-VIS, H, C NMR spektroskopisi ve ESI-MS spektrometresi dahil standart tekniklerle karakterize edildi. Aren rutenyum bileşiğinin termal bozunma ölçüm verileri incelendi. Bu ölçümler Termogravimetrik analiz (TGA) ve Diferansiyel termal analiz (DTA) teknikleri ile yapıldı.

In this paper, novel poly(esterimide)s with attached as a side group azobenzene chromophores are presented. The polymers differing in substituents on the azobenzene moieties and chromophore concentration. Azopolymers were obtained by a twostep synthetic approach. This include the preparation of a precursor poly(esterimide) with benzene moiety pendant from main chains, followed by the covalent bonding of the NLO chromophores onto the polyimide backbone by a post-azo-coupling reaction using the following coupling components: p-nitroaniline, 2-cyan-4-nitroanilin, 2,4-dinitroaniline and Disperse Orange 3. The precursor poly(esterimide) was obtained from synthesized 2,2 0 [N-phenylethyloaniline-di(4-estro-1,2dicarboxylic)]anhydride and 4,4 0 -methylene bis(2,6-dimethylaniline). The degree of functionalization of the poly(esterimide)s was estimated by UV-vis spectroscopy. The obtained polymers were characterized and evaluated by FT-IR, 1 H NMR, X-ray, UV-vis, DSC and TGA. The results showed the azopolymers exhibited high glass transition temperatures (T g ¼ 159{224 C), high thermal stability with decomposition temperatures in the range of 311-334 C and good solubilities in common organic solvents. First time two-photon absorption (TPA) coefficient in cast films of amorphous azopoly(esterimide)s was measured using Z-scan experiment which was performed with femtosecond laser pulses 100 fs at 800 nm. The TPA coefficient was determined to be in the range of 1.54-11.69 cm/GW.

Controlling the polymerization of supramolecular self-assembly through external stimuli holds great potential for the development of responsive soft materials and manipulation at the nanoscale. Vinyl esters of bis(leu or val)fumaramide (1a and 2a) have been found to be gelators of various organic solvents and were applied in this investigation of the influence of organogelators’ self-assembly on solid-state polymerization induced by gamma and ultraviolet irradiation. Here, we report our investigation into the influences of self-assemblies of bis(amino acid vinyl ester)fumaramides on gamma-ray- and ultraviolet-induced polymerization. The gelator molecules self-assembled by non-covalent interactions, mainly through hydrogen bonds between the amide group (CONH) and the carboxyl group (COO), thus forming a gel network. NMR and FTIR spectroscopy were used to investigate and characterize supramolecular gels. TEM and SEM microscopy were used to investigate the morphology of gels and polyme...

The old concept of complementarity, connected with the process of molecular recognition represents a simple approach to understanding molecular assembling. The noncovalent interactions governing (self)assemblies are fundamental to supramolecular chemistry and crystal engineering. Among noncovalent interactions governing molecular assembling, hydrogen bonding plays the leading role. A few examples of molecular assembling relevant to life processes and (bio)nano materials reveal the importance of this phenomenon. Systematic analysis of hydrogen bonding patterns, as a function of proton donor and acceptor properties, and stereochemical parameters, including chirality, is presented for a large number of di(amino acid) and di(amino alcohol) derivatives with oxalyl, phthaloyl, and fumaroyl bridges. Particular attention will be given to the molecular topology of such hydrogen bonded assemblies in terms of crystal engineering.

Ce travail participe a l&#39;amelioration de la selectivite et de l&#39;adaptabilite au milieu d&#39;etude d&#39;une membrane de dialyse en poly(acrylonitrile-co-methallyl sulfonate), plus communement appelee AN69. A cet effet, nous.avons procede a des modifications de la surface de cette membrane par simple adsorption d&#39;un polyelectrolyte cationique, le chlorure de poly(diallyldimethylammonium), note PDAMA. Les modifications physico-chimiques de la membrane AN69 sont suivies par la determination des nombres de transport de Li + a partir de mesures de potentiel de membrane, par des mesures directes de flux dc diffusion de plusieurs solutions d&#39;electrolytes et par des mesures de permeabilite hydraulique, avant et apres modification. Il apparait que l&#39;adsorption du polyelectrolyte sur la surface de la membrane est essentiellement due a des interactions electrostatiques et ne peut etre decrochee que dans une solution concentree de chlorure de sodium (&gt; 2 mol/L). Par aill...

Two types of poly(5-phenyl-2-norbornene) were synthesized via ring opening metathesis and addition polymerization. The polymers sulfonation reaction under homogeneous conditions resulted in ionomer with high sulfonation degree up to 79% (IEC 3.36 meq/g). The prepared ionomer was characterized by DSC, GPC, 1H NMR and FT-IR. Polymers for electromechanical applications soluble in common polar organic solvents were obtained by replacing proton of sulfonic group with imidazolium and 1-methylimidazlium. Membranes were prepared using the above-mentioned polymers and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4), as well as mixtures with polyvinylidene fluoride (PVDF). Mechanical, morphological, and conductive properties of the membranes were examined by tensile testing, SEM, and impedance spectroscopy, respectively. Dry and air-stable actuators with electrodes based on SWCNT were fabricated via hot-pressing. Actuators with membranes based on methylimidazolium containing ionomers ...

A new efficient route for the synthesis of a cyclic monomer of perdeuterated poly(ethylmethylsiloxane) (PEMS) is reported. The perdeuterated cyclotrisiloxane has been prepared for the first time in an eight-step reaction starting from fully deuterated methanol and ethanol. Chromatographic and spectroscopical methods indicate a high purity as well as almost total deuteration of the 2,4,6tri(pentadeuteroethyl)-2,4,6-tri(trideuteromethyl)cyclotrisiloxane. All the reaction steps have been previously investigated by the similar preparation of the protonated 2,4,6-triethyl-2,4,6-trimethylcyclotrisiloxane as a model for the synthesis of the corresponding perdeuterated monomer.

The synthesis of novel fused pyrimidines and imidazole derivatives from 2-amino-s-triazino[1,2a]benzimidazoles 2a-e and 3a-c was successfully carried out by a ring annelation reaction in a very good yield. Compound 3c was screened for analgesic activity against acetic acid irritation and has shown protection equal to the reference drug (diclofenac sodium). The acute toxicity study revealed that compound 3c is safe up to 300 mg/kg and there is no sign and symptoms of toxicity and mortality for 72 hours.

Most of the synthesized compounds which have liquid crystalline character in their composition comprise aromatic molecules. Furthermore there are few jobs that replace this type of molecules by inhomogeneous molecules that have LC character. We will replace the aromatic rings by units of 1,3,4-oxadiazole and study the effects of these new components of the transition temperatures and the Thermodynamic characteristics of n-alkanes in these two LC's phases. have been investigated by inverse gas chromatography. The transition temperatures obtained by GC are in good agreement with those found by DSC. The results are interpreted in terms of parameters "b" and related thermodynamic quantities.

A novel Sulfonated Polystyrene (PSS) has been synthesized by sulfonation polystyrene waste for a comparative study of proton exchange membranes (PEM) that is intended for fuel cell applications. The degree of sulfonation (DS) of the sulfonated PS was determined using titration method. We systematically investigated the water uptake, proton conductivity, and methanol permeability of the cross-linked membranes. The mass averaged molecular weights Mw of PSS was estimated from intrinsic viscosities measured in sulfuric acid solutions. A related homopolymer was characterized by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The structures of PSS were elucidated, and the effect of sulfonation level on the PSS FT-IR spectrum was studied. PSS membrane surface morphology was investigated by SEM and AFM. The highest of proton conductivity of the membrane in the temperature range of 25-750C was found to be 3.8 µS/cm

By ensuring quality, safety, and effectiveness, formulation development is a crucial component of pharmaceutical development and is necessary for the product's therapeutic and commercial success. By bypassing the GIT and hepatic first pass impact, the buccal mode of administration offers numerous benefits, including increased patient compliance. Hardness, weight uniformity, thickness, friability, swelling index, mucoadhesive strength, surface pH, drug-excipient interaction studies, and drug content uniformity were among the metrics used to describe buccal tablets. For both systemic absorption and local administration in the oral cavity, the constant production of saliva and its subsequent swallowing might result in significant drug depletion from the dosage form and, consequently, limited bioavailability. In order to avoid the mentioned drawbacks of traditional oral dosage forms (i.e., tablets, capsules, syrups, etc.), new transmucosal routes such as nasal, rectal, vaginal, ocular, and oral mucosae are being explored as potential substitutes for current oral drug delivery methods. One of the target areas for administering medications in a wide range of dose forms is the buccal oral mucosa, especially for medications intended for systemic absorption and local distribution in the oral cavity.

The controlled polymerization of N-isopropyl acrylamide (NIPAM) is reported in a range of international beers, wine, ciders and spirits utilizing Cu(0)-mediated living radical polymerization (SET-LRP). Highly active Cu( ) is first formed in situ by the rapid disproportionation of [Cu(I)(Me 6 -Tren)Br] in the commercial water-alcohol mixtures. Rapid, yet highly controlled, radical polymerization follows (Đ values as low as 1.05) despite the numerous chemicals of diverse functionality present in these solvents e.g. alpha acids, sugars, phenols, terpenoids, flavonoids, tannins, metallo-complexes, anethole etc. The results herein demonstrate the robust nature of the aqueous SET-LRP protocol, underlining its ability to operate efficiently in a wide range of complex chemical environments.

Neutron scattering experiments are a unique tool in material science due to their sensitivity to light elements and magnetic induction. However, for kinetic studies the low brilliance at existing sources poses challenges. In the case of periodic excitations these challenges can be overcome by binning the scattering signal according to the excitation state of the sample. To advance into this direction we have performed polarised and time resolved grazing incidence neutron scattering measurements on an aqueous solution of the polymer F127 mixed with magnetic nano-particles. Magnetic nano-composites like this provide magnetically tuneable properties of the polymer crystal as well as magnetic meta-crystals. Even though the grazing incidence small angle scattering and polarised signals are too weak to be evaluated at this stage we demonstrate that such experiments are feasible. Moreover, we show that the intensity of the 111 Bragg peak of the fcc micellar crystal depends on the actual shear rate, with the signal being maximised when the shear rate is lowest (and vice-versa).

Neutron scattering experiments are a unique tool in material science due to their sensitivity to light elements and magnetic induction. However, for kinetic studies the low brilliance at existing sources poses challenges. In the case of periodic excitations these challenges can be overcome by binning the scattering signal according to the excitation state of the sample. To advance into this direction we have performed polarised and time resolved grazing incidence neutron scattering measurements on an aqueous solution of the polymer F127 mixed with magnetic nano-particles. Magnetic nano-composites like this provide magnetically tuneable properties of the polymer crystal as well as magnetic meta-crystals. Even though the grazing incidence small angle scattering and polarised signals are too weak to be evaluated at this stage we demonstrate that such experiments are feasible. Moreover, we show that the intensity of the 111 Bragg peak of the fcc micellar crystal depends on the actual sh...

The present research contains the photochemical treatment (PCT) of residual wastewater effluent derived from an advanced primary treatment process (APT). The application employed an ultraviolet light system, hydrogen peroxide and ozone as a free hydroxyl's radicals generator; strong oxidants for the organic contaminants mineralization which affects the water quality. The aliquots of the APT and PCT were analyzed by determination of the parameters as the color, turbidity, electric conductivity, COD, UV-Vis spectrometry, anion and cation techniques, enabling the determination of the photo-oxidative wastewater treatment efficiency. The microbiological assays denote the one hundred percent photo-oxidative effectiveness for the removal of undesirable microorganisms. After the treatment, the water is suitable for its reuse, commercialization or spill into a body receptor without any risk for the environment or the health.

A series of 16 complexes of 1,2-bis(benzothiazolyl) benzene and 1,2-bis(benzothiazolyl)-4-methyl benzene compounds with Ti(IV), Zr(IV), V(III), Fe(III), Fe(II), Co(II), Ni(II) and Cu(II) were synthesized and characterized. After activation with methylalumoxane (MAO), these complexes showed variable activities towards ethylene polymerization. The polymerization activities of the catalyst system 3, 5, 7 and 15 /MAO were investigated under different polymerization conditions. The highest activity 625 [Kg PE / mol Cat. H] is obtained by the catalyst system 5/MAO at 50 °C and cocatalyst concentration of 1000 equivalents. The produced resins showed high molecular weights associated with broad or even bimodal molecular weight distributions for all catalysts systems except the polymers produced with nickel catalysts 9 and 17/MAO.

A series of 16 complexes of 1,2-bis(benzothiazolyl) benzene and 1,2-bis(benzothiazolyl)-4-methyl benzene compounds with Ti(IV), Zr(IV), V(III), Fe(III), Fe(II), Co(II), Ni(II) and Cu(II) were synthesized and characterized. After activation with methylalumoxane (MAO), these complexes showed variable activities towards ethylene polymerization. The polymerization activities of the catalyst system 3, 5, 7 and 15 /MAO were investigated under different polymerization conditions. The highest activity 625 [Kg PE / mol Cat. H] is obtained by the catalyst system 5/MAO at 50 °C and cocatalyst concentration of 1000 equivalents. The produced resins showed high molecular weights associated with broad or even bimodal molecular weight distributions for all catalysts systems except the polymers produced with nickel catalysts 9 and 17/MAO.

The dielectric spectra and conductivity properties of neat poly(epichlorohydrin-co-ethylene oxide)(PECH-co-EO) copolymer and two modified copolymers with a 20% or 40% of dendron 3,4,5tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate units were analysed. A process of thermal orientation was applied to the copolymers to fine-tune the molecular motion of the side chains and determine their validity for cation transport materials. The study was conducted using Dielectric Thermal Analysis (DETA). The spectra of the modified unoriented and oriented copolymers consisted of five dielectric relaxations (δ, γ, β, α Tg , and α melting ). The analysis of the relaxations processes shows that as the grafting with the dendron units increases, both the lateral and main chains have a greater difficulty moving. The thermal orientation induces in the main chain partial crystallization, including the polyether segments, and modifies the cooperative motion of the main chain associated with the glass transition (α Tg ). A deep analysis of the electrical loss modulus revealed that the degree of modification only modifies the temperature peak of each relaxation, and this effect is more perceived if the dendron unit content is higher (40%). The thermal orientation process seems equal to the spectra of CP20-O and CP40-O to the point that the degree of modification does not matter. Nevertheless, the fragility index denotes the differences in the molecular motion between both copolymers (40% and 20%) due to the thermal orientation. The study of the electric conductivity showed that the ideal long-range pathways were being altered by neither the thermal orientation process nor the addition of dendrimers. The analysis of the through-plane proton conductivity confirmed that the oriented copolymer with the highest concentration of dendrimers was the best performer and the most suitable copolymer for proton transport materials.