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The aim of this study is to obtain and characterize a range of hybrid polymeric films with different collagen content and synthetic poly-alcohol as polyethylene glycol (PEG). Films were obtained using a “casting solution method” by a cross-linking process at room temperature. The new collagen hybrid biofilms are devoted to cell growth and proliferation. Keywords: collagen gel, hydroxyapatite, ternary hybrid biofilms

Lyocell fibers are ecological cellulose regenerated fibers and represent the most important discovery in the field of “artificial fiber engineering”. These fibers can be situated at the border between natural fibers (in terms of comfort, biodegradability) and chemical fibers (by high resistance in dry and wet environment, low contraction). In order to characterize the structural Lyocell fiber properties, electronic microscopy analyses, birefringence and X-ray diffraction have been accomplished. The present analysis on the structural properties of Lyocell fibers allowed to conclude that the microscopic images depict that Lyocell fibers present uniform longitudinal aspect and regular cross-section; the Lyocell fiber birefringence is 1.6 times higher than similar feature of viscose fiber (0.04263 as compared to 0.0265) and the diffraction analysis reveals that the distortion degree of the crystal lattice of Lyocell and viscose fibers is in accordance with the crystalline factor. The average tenacity – deformation diagrams for Lyocell and viscose fibres, in conditioned and in wet medium, allowed to determine the rheological parameters of the fibers. Keywords: Lyocell fiber properties, electronic microscopy, birefringence, diffraction analyses

Lactic ester of maleoabietic acid (RAMALA) was obtained by chemical reaction between Diels-Alder adduct of resin acids with maleic anhydride (RAMA) and lactic acid (LA). The obtained product was characterized by elemental analysis and by spectroscopic methods (IR and NMR). Curing reaction of three epoxy resins (diglycidylether of bisphenol A (DGEBA), diglycidyl ether of hydroquinone (DGEHQ) and diglycidylaniline (DGAN), with (RAMALA) in the presence of triethylbenzylammonium chloride (TEBAC) as catalyst was examined by differential scanning calorimetry (DSC) at different heating rates. Using the literature methods the kinetic parameters of crosslinking reactions were obtained. The activation energies of the curing reactions varied in the range of 48 to 85 kJmol-1 depending on epoxy systems. The thermal behaviour of cured products was also investigated using dynamic thermogravimetric analysis (TGA) technique. The cured products present good thermal stability and the activation energies of the degradation process exhibit values between 82 to 155 kJ×mol-1. Keywords: Diels-Alder adduct of resin acids, lactic ester of Diels-Alder adduct of resin acids with maleic anhydride ,epoxy resin, crosslinking reactions, thermal properties

The qualitative and quantitative information concerning the dependence between the kinematic viscosity and the activation energy of the viscous flow by the polyvinyl chloride – thermoplastic polyurethane blends composition were obtained. The results reveal that the blend composition and the melt temperature are the most important parameters that control the PVC – TPU blends melt processing. A high injection speed increases both the tensile strength and the breaking elongation. The shorter time for the mould loading increases the tensile strength and decreases the breaking elongation. The measurement of the rheological properties based on the MFI methods is a good instrument for the estimation of the rheological properties of the polymeric blends in practical conditions Keywords: polyvinyl chloride -thermoplastic polyurethane blends, rheological properties, kinematic viscosity, melt viscous flow, activation energy of the viscous flow

The optimization of the ultrasound welding of composed materials means finding an objective function that comprises all acoustic, mechanical and technological parameters and determining the minimum cost of the process or the maximum productivity in obtaining a superior quality of the welded join.In the paper there are presented the dependency of the quality of composed materials welded joins on acoustic parameters and mechanical and technological parameters. Key words: ultrasounds, welding, plastic material, technology

Experimental investigations of a diblock copolymer (polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) film doped selectively with tetrakis(4-carboxyphenyl)porphine (TCPP) into the nanoscale spherical domains of P4VP) used as target in a Nd: YAG laser (l = 532 nm) ablation process, were performed. The ionic current oscillations and the velocity of diblock copolymer plasma plume were experimentally obtained . Keywords: polymer, laser ablation

Polymer plasma laser ablation has been investigated theoretically. An elegant mathematical tool using the fractal structure of space-time was developed. The model was verified with good accuracy on the existing experimental results. Keywords: polymer, laser ablation, fractal space-time theory

The group of circular knitting machines with large diameter includes machines with one or two needle-beds with diameters higher than 178 mm and that use knitting process with final loop for stitch forming. The fabrics produced by circular knitting machines with large diameter are designed both for underwear products, clothing products and other destinations items (items for interior decorations, bed linen, technical articles, toys). Manufacturers of circular knitting machines have improved these machines in particular for: increasing productivity and polyvalence of these machines, reducing production costs, increasing quality of knitted fabrics. Appearance and uniformity of knitted fabrics are quality characteristics that directly depend on technological parameters of knitting. The paper presents ways for adjustment of fabric density at knitted fabrics produced by circular knitting machine with large diameter, type interlock, belonging to Mayer & Cie company. Keywords: circular knitting machine, knitted fabrics, fabric density

Platinum nanoparticles with sizes between 10 and 42 nm have been obtained by a sonoelectrochemical method in the presence of a water-soluble polymer, poly(amidehydroxyurethane) (PAmHU), which acted as a coating agent. The PAmHU stabilized Pt nanoparticles were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis and FTIR spectroscopy and dimension distribution and Zeta potential analysis. The analyses showed the fact that these nanoparticles are capped by the polymer, which confers them water-solubility and stability. Keywords: platinum nanoparticles, poly(amidehydroxyurethane), sonoelectrochemical synthesis

This paper presents the preparation by phase inversion of polysulfone and cellulose acetate ultrafiltration membranes (UF1-UF36) with various amounts of PEG additives (1000, 2000, 4000 Da), designed for the whey protein separation. To establish optimal operating conditions for membrane separation and the membrane with the best characteristics for the ultrafiltration of whey, we determined the flow variation of the two types of whey (pH=6.21, pH=4.35) with different parameters: whey temperature, operating pressure, protein retention and clogging phenomenon. All the results indicated that at the same protein separation efficiency (MWCO), the polysulfone membranes present higher flows than cellulose acetate membranes and their use in the acid whey ultrafiltration process lead to a whey protein concentrate with a protein content about 5 times higher than the initial whey content (6.4 kg/m3). The best protein retention 98.73% was obtained for UF18 membrane (20% PS, 2 % PEG 4000), with optimal flow rate (23.9·10-6 m3/m2s) for acid whey, operating at 50oC and 106 Pa. Keywords: membranes, ultrafiltration, proteins, recovery