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Collagene-based nanocomposite membrane films were obtained by dispersing nanohybrides formed by modifying a layered silicate with quebracho and methylene blue in a collagen-gel matrix. TGA and XRD analyses proved the intercalation of active substances between the silicate layers. Thermal stability of the binary nanohybrides decreases with the increase of active substance content. Nanocomposites showed an improved thermal stability compared to collagen. Modifying the silicate with active substances influences the hydrophilicity of final nanocomposite by reducing the water vapour adsorption. Although the methylene blue is a disinfectant, it influences negatively the growth and development of the fibroblasts hence it is inappropriate for use in case of an open lesion. Quebracho is biocompatible and has a biostimulating effect on the growth and development of the fibroblasts, bioactive films thus obtained being good antiseptic and regenerating patches. Keywords: nanocomposites, montmorillonite, collagen, methylene blue, quebracho

The paper presents results concerning the synthesis and characterization as polymer processing aids (lubricants) and/or as tribological lubricants of some monoesters of different monocarboxylic acids with variable length, along with some special aliphatic-aromatic alcohols with a complex structure and/or with superior (larger) alcohols (exclusively aliphatic). The monocarboxylic acids considered were n-butyric, n-octanoic and oleic, respectively, while the alcohols taken into consideration were isodecyl (iso-C10), isotridecyl (iso-C13), as for the aliphatic group, 2-phenoxy-ethanol, 2-[(o-sec-butyl)phenoxy]ethanol, and 2-[(p-nonyl)phenoxy]ethanol, respectively, as for the complex aliphatic-aromatic group. Under these circumstances it became possible to investigate the influence of the structure on the main physico-chemical properties of these synthetic oils as well as on their lubricating characteristics. The results recorded fully certified the validity of the research program. Keywords: complex monoesters, synthetic oils, lubricants, phenoxy-ethanols

Nanocomposites were obtained by dynamical melt blending. Some layered silicates and fillers based on nanocarbon were studied as nanofillers. The morpho-structural (XRD, HRTEM), thermal (TGA), dynamic-mechanical (EL) and mechanical (DShD, Ak. si) characteristics were examined. Nanocomposites with intercalated, partially exfoliated/partially intercalated and exfoliated lamellar structure with uniform dispersion of the nanofiller in the polyamide matrix were obtained. The nanocomposites exhibit thermal stability and improved properties as compared to the starting material. Keywords: PA6, nanocomposites, montmorillonite, nanocarbons

The susceptibility of starch-based biomaterials to enzymatic degradation by a-amylase and peroxidase enzymes was investigated. A polymeric blend of corn starch with polyethylene, designated by SLDPE, was studied. The degradation was evidenced by gravimetry, scanning electron microscopy (SEM), FTIR spectroscopy, and X-ray diffraction. Analysis performed showed that starch blend is susceptible to enzymatic degradation, significantly in the presence of ionic liquid, as evidenced by increased weight loss and reducing sugars in solution. SEM analysis evidenced the presence of fractures and pores at the materials surface as a result of starch degradation by a-amylase. FTIR spectra confirmed a decrease on the band corresponding to glycosidic linkage (-C-O-C-) of starch. Keywords: corn starch, LDPE/starch blends, degradability, enzymes, ionic liquid

Research and Development National Institute for Chemistry and Petrochemistry–ICECHIM, 202 Splaiul Independenþei, 060021, Bucharest, Romania The curing reactions at microwaves for two different systems consisting of diglycidyl ether of bisphenol A (DGEBA) and 4-aminoazobenzene (AAB) and diglycidyl ether of ethylene glycol (DGEEG) and AAB were studied through differential scanning calorimetry (DSC) and FTIR spectroscopy. Keywords : epoxy, azo, microwaves, FTIR, calorimetry

Various telechelic bifunctionalized siloxane derivatives were reacted with titanocene dichloride. The reactant functionality is favorable for the formation of the poly(ester), poly(amine), poly(ether), and poly(silyl-ether) depending on the functional groups of the used siloxane precursors. The interfacial condensation technique was applied and, excepting polyesters, in the other cases, the inverse interfacial system was used. CHCl3 was used as a solvent for siloxane phase and triethyl amine was added as a hydrochloric acid acceptor. The very fast reactions occurred at room temperature with colour change from red-orange to yellow. The poly(ester) was also synthesized in solution by using DMF as a solvent. The formation of new structures was verified by FTIR and their thermal behaviour was investigated by TGA and DSC. SEM and Energy Dispersive X-Ray system (EDX) were used to show the morphology of the poly(ether). The repartition of Ti was investigated by EPR. Keywords: siloxane-titanocene copolymers; polycondensation; metallocene; siloxane

Mechanism and kinetics of dispersion polymerization of styrene in the presence of a new macromer based on 2-ethyl-2-oxazoline have been investigated. Partial conversion-time curves have been obtained by continuous NMR measurements. Final conversion of styrene was 88% in contrast to 35% for oxazoline macromonomer. The kinetic data proved that particles become sterical stable at 15% conversion. The weight average molecular weight and polydispersity index are in the range of typical dispersion polymerization. The thermal stability and glass transition temperature are increased when a higher amount of stabilizer is used. The presence of the macromer on the surface of the final beads and the fraction of grafted stabilizer were evaluated by XPS. Keywords: dispersion polymerization, macromonomers, 2-ethyl-2-oxazoline, X-ray photoelectron

New formaldehyde resins were synthesized by the polymerization of a mixture of 4,4’-methylenedianiline (MDA) and p-tert-butylphenol (p-TBPH) with formaldehyde (FA) (at a molar ratio monomers/formaldehyde, 1/1), in the presence of an acid catalyst (HCl).The mixture of DMF/toluene was used as reaction medium and as carrier for the aqueous condensation. These polymers were characterized by elemental, spectral and thermal analysis and used as hardener for epoxy resins (diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of hydroquinone (DGEHQ)). The obtained resins have low molecular weight and are soluble in medium and high polar solvents. The curing and the temperature behaviour of epoxy resin/formaldehyde resin systems were investigated using differential scanning calorimetry (DSC) and thermogravimetry (TG) techniques. The activation energies of the curing reactions are situated in the range of 52 to 66 kJ×mol-1 for DGEBA systems and at 54 to 72 kJ×mol-1 for DGEHQ systems. The cured products have good thermal properties, and the activation energies of the degradation reactions have values between 36-65 kJ×mol-1 for epoxy systems. Keywords: formaldehyde resins, epoxy resin, crosslinking reactions, thermal properties

The present study is aimed to investigate the effect of damage due to hygrothermal fatigue on the mechanical behaviour of CFRP (Carbon Fiber Reinforced Polymer) laminates as well as on the skin-core interfacial stress field in sandwich structures having CFRP laminates as core material and aluminum as skin. The above behaviour was both experimentally and analytically studied using a model recently developed by the CMG group at University of Patras. Keywords: hygrothermal fatique, polymeric composite laminates, sandwich structures, interfacial phenomena

Damping capacity is comparatively analyzed for a composite with polymer matrix (vinyl ester) and a shape memory alloy (copper-zinc-aluminium). A good damping capacity of shape memory alloy results in structural transformation domain in detriment of composite material. The theoretical model developed on the analyzed material behaviour describes qualitatively the temperature dependence of the dissipation capacity. Keywords: polymer, shape memory alloy, dissipation capacity, fractal