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The main goal of this study was to investigate the capacity of dendritic polymers to encapsulate the antitumoral drug (5-fluorouracil) using non-covalent methods. As nanoscale containers four polyamidoamine dendrimers (PAMAM) types of different generations were used. The antitumoral drug encapsulation efficiency of these dendrimers was pointed out using different methods like FTIR Spectroscopy, X-Ray Photoelectron Spectroscopy (XPS) and Thermogravimetric analysis (TGA). The obtained results showed that the dendrimers generation exhibits a strong influence on the 5-fluorouracil encapsulation. Keywords: dendrimer, antitumoral drug, FTIR analysis, X-Ray Photoelectron Spectroscopy

Fiber-reinforced polymeric composite materials present an orthotropic distribution of their mechanical and elastic characteristics. This behaviour is mainly due to the fact that the fabric used behaves differently under the same type of stress, on different directions. The procedure described by our paper enables researchers to determine the elastic modulus of such materials, on three different directions, using a specially designed specimen. The finite element analysis revealed that there were no significant influences on the strains and deformations existing in the measurement area, concerning the shape of the test specimen or its fastening. The results obtained for three composite materials used to validate the procedure showed that two of the materials having orthotropic properties, exhibit different elastic modulus. Keywords: polymeric composite, deformations, octagonal specimen, orthotropy, elastic characteristics

New copolymers having 2-anilinoethanol and N-sulfopropylaniline acid, as units in the main chain were prepared by cyclic voltammetry from 1M H2SO4 aqueous solution, and deposited on Pt and ITO electrodes using solutions containing different monomers ratios of 1:1, 1:2 and 2:1. The electropolymerization processes were carried out by sweeping the working electrode potential between 0.0 V and 1.3 V at 50 mVs-1, for 20 cycles. The copolymers were deposited as green layers on working electrode surface. All copolymers exhibit electrochemical activity in H2SO4 solution but they became unstable starting with the second cycle. Among all synthesised copolymers, only PAnEtOH-AnPS-12 shows electrochemical activity in acetate buffer solution, pH 6.5. Raman spectra recorded for PAnEtOH and PAnEtOH-AnPS-21 revealed the presence of the characteristic bands for polyanilines in both oxidized and reduced form. SEM and AFM micrographs revealed that the copolymers layers present a smooth and compact morphology with small roughnesses. It was evidenced that the change of the electrolysis medium pH induces changes in the morphology of the copolymers layers. Copolymers having both aniline monomers were obtained from acetate buffer solutions at pH 4.5 and characterized. Keywords: self-dopable polyaniline; sulfonated polyaniline; 2-anilinoethanol; electrochemical deposition; cyclic voltammetry

The study of modification by melt alloying of recovered polypropylene with styrene and a-methylstyrene-diene block-copolymers is presented in this paper. The block-copolymers were synthetized with the same composition and molecular weight in order to relieve more accurately the influence of the component block nature upon the modification degree of the polyolefin. It was found that only the nature of the diene block has a significant influence on the intensity of the modification degree for recovered polypropylene. Keywords: recovered polypropylene, styrene-isoprene block-copolymers (SIS), styrene-butadiene block-copolymers (SBS), a-methylstyrene-butadiene block-copolymers (aMeSBaMeS)

The present work reports on the synthesis and biomineralization capacity of hydrogel networks composed of Bombyx mori silk fibroin, polyacrylamide and carboxylated multiwall carbon nanotubes soaked in simulated body fluid. Hydrogels were fabricated by the polymerization of acrylamide and N,N’-methylenebisacrylamide in silk fibroin solution containing carboxylated multiwall carbon nanotubes with potassium persulphate/triethanol amine redox system as initiator. The incorporation of the fibroin and MWCNT-COOH within the polymer network was proved by FTIR spectroscopy. Swelling measurements in saline solution were performed to evaluate the behaviour of these hydrogels having various compositions. Biomineralization assays in simulated body fluid solution showed the presence of apatite-like crystals onto the surface of the materials. Beneficial effects upon biomeralization process of the carboxylated nanotubes were further discussed. Mechanical compressive tests revealed good strengths for the silk hydrogels depending on their composition. The results of this study lay down the fundament for the use of these silk fibroin biomaterials in bone tissue engineering applications. Keywords: silk fibroin, carbon nanotubes, biomineralization, apatite, compressive strength

Cellulose and polyhydroxyalkanoates, polymers from renewable resources, have been intensively studied for the last decades and they are the main topic of this paper. Bacterial cellulose pellicles (BC) were synthesized in static culture fermentations and ultrasounds were used to disintegrate them into fibers (us-BC). Microcrystalline cellulose (MCC) and us-BC were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and infrared spectroscopy (ATR-FTIR) with a view toward their use in fully biodegradable and biocompatible polymer composites. Mechanical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) modified with the two types of celluloses were also investigated. AFM images showed that big aggregates of BC fibers disappeared after ultrasound treatment but small aggregates coexist with separated fibers in us-BC sample. Higher XRD crystallinity and crystallite dimension were obtained for us-BC as compared to MCC. Mechanical tests on poly(3-hydroxybutyrate-co-3-hydroxyvalerate), neat and modified with the two cellulosic fillers, showed that the highest values of tensile strength and modulus were obtained in the case of the composite containing us-BC. Keywords: bacterial cellulose, polyhydroxyalkanoates, XRD, polymer composites, AFM

The paper presents experimental data regarding organic modified silica hybrids having embedded a non-ionic dye – Disperse Red 1, deposited on cotton fabrics. Hybrids were prepared by sol-gel processes using tetraethoxysilane and various trialkoxysilanes as organic network modifying agents, in acid catalysis and in the presence of Disperse Red 1. Control of the interactions between the organic non-ionic dyestuff and its embedding matrices allows tailoring the performance of the resulted coatings. Light and wash fastness and thermo-mechanical properties of the coated fabrics were investigated and correlated to the composition and morphology of the organic-inorganic coating materials. The results show that chemical composition of the impregnating bath have a decisive role in determining shade, intensity, fastness to light or washing of the coloured hybrid coatings as well as thermo-mechanical and hydrophobic properties of the coated textile fabrics. Keywords: silica hybrids, non-ionic dye, cotton fabrics, contact angle, thermal stability

The influence of various additives, like salts, alkohols, surfactants and water-miscible organic solvents, upon the cloud point of a, w - (2-hydroxyethoxy) oligo(propylene oxide) in aqueous solutions was investigated for the first time. The results showed that NaH2PO4, NaCl, NaBr, NaI, 1-butanol, ethylene glycol and dimethylsulfoxide decreased the cloud point, while 1,2-propylene glycol, sodium dodecylsulfate, nonylphenyl ethoxylated with 9 moles of ethylene oxide and dioxane increased it. Addition of N,N-dimethylformamide practically had no influence upon the cloud point on the concentration interval investigated. The LCST of a, w - (2-hydroxyethoxy) oligo(propylene oxide) in aqueous solution was also determined and it was found equal to 19°C. Keywords: a, w-(2-hydroxyethoxy) oligo(propylene oxide), thermosensitive polymers, cloud point, low critical solution temperature (LCST), additives

This paper presents new composite materials used in extension of growth season of vegetable crops, in countries with a mild continental transition climate, for constructions type tunnel. Composite materials are realized from two components, namely textile materials with generated heat potential and polyethylene polymer foils, with a selection possibility of wave lengths in IR domain. For insurance of microclimate conditions, especially of thermal performance, the materials have been tested from electrical and mechanical point of views, following the generated heat flux and its elastic deformations for a known material width. Keywords: tunnel, horticultural crops, composite materials

Alkylation of benzene with bioethanol (95% and 100% concentration) has been done in a laboratory tubular reactor using a new modified zeolitic catalyst. The alkylation experiments have been done at different reaction temperatures , pressures and benzene/bioetanol molar ratio in order to establish their influence on the final composition of the reaction product, selectivity and conversion. The feed and products are analysed by gas chromatography. There was small differences between 100% bioethanol and 95% bioethanol aqueous solution in experimental alkylation results that it possible to use 95% bioethanol solution as alkylating agent. Keywords: alkylation benzene, bioethanol, ethylbenzene, zeolitic catalyst