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Among the composition and morphological structure field of biomaterials, the biodegradable biocomposites based on, synthetic and natural polymers as biocompatible spongious matrices has been studied. The biodegradable synthetic polymers have good mechanical properties, low toxicity and a controlled degradation kinetic. However, these polymers are hydrophobic and do not exhibit adequate surface for cells attachment and proliferation because of receptors absence for cells recognition. The natural polymers show good cellular interaction and high hydrophilicity. The advantages of biocomposites made of both synthetic and natural polymers are holding both physico-chemical properties of synthetic polymers and biocompatibility, cellular adhesion properties and variety of biological interactions induced by the contact between cells and natural polymeric support. The aim of this study was the synthesis of biocompatible porous structures by compounding synthetic polymers - (poly(L-lactic acid) (PLLA), poly(D,L-lactic-co-glycolic acid) (PLGA) which are biocompatible, biodegradable but hydrophobic, with natural polymer – collagen, the main protein of extracelullar matrix. The biocomposites were prepared in a polymer: collagen ratio of 2:1 by adding synthetic polymer solution, solved in chloroform, to aqueous collagen gel. The synthesis of biocomposite matrices was achieved by lyophilizing of synthetic polymer/collagen blends after dialyse against 1M KCl. Both uncrosslinked and crosslinked samples were prepared. As standard sample the uncrosslinked and crosslinked collagen matrices were chosen. The morphology of biocomposite matrices PLLA/collagen, PLGA/collagen was characterized by SEM in order to investigate the macro-, micro and nanoporosity. Physico-chemical characterization was focused on thermal stability (DSC and TGA) and surface hydrophilic character by water vapours absorption, water vapours permeability and water absorption. Keywords: biocomposites, collagen, biodegradable synthetic polymers

Polymeric nanoparticles are widely used as drug carriers in order to achieve the targeting of drug to the ill tissue. N-vinyl-2-pyrrolidone and itaconic anhydride were copolymerized and the alternating copolymer was then grafted with PEG of different molecular weight, to form amphiphilic copolymers. The grafted copolymers have been used to prepare polycaprolactone nanoparticles. The PCL has been chosen as it can mimic the hydrophobic drugs. Several emulsions were stabilized and characterized by SLS. The synthesized copolymers proved to be effective in stabilizing nanoparticles. The mean diameter of nanoparticles was stable in time, over 12 weeks. Keywords: Polycaprolactone nanoparticles, amphiphilic surfactants, radical polymerization

This paper presents the results of the experimental researches made on an extruder for pasta, in which the extrusion die has the active extrusion surfaces from two different materials: plastic and metallic. The subject is focused on polytetrafluoroethylene, to indicate the advantages of this material comparative with bronze. The experimental part consists of diameter measurements of the intern extrusion holes with the optic microscope. Keywords: polytetrafluorethylene, bronze, extrusion, die

The paper presents experimental data regarding a number of five new polymeric termo-resistant pigments synthesized by condensation of Perylene 3, 4, 9, 10-tetracarboxylic dianhydride with 2-Cl-p-phenilendiamine in various molar ratio. Reaction products were purified and characterized by elemental analysis, UV-VIS, IR and thermal analysis. Keywords: perylene 3, 4, 9, 10-tetracarboxylic dianhydride, 2-Cl-p-phenilendiamine, polymeric thermoresistant pigments

The concept of thermal homogeneisation efficiency, hht was defined, giving an indication on the thermal homogeneity realised by a certain zone through the heat generated by internal friction. Its optimal value corresponds hht = 1. This concept was then applied to the calculus of thermal homogeneity at the flow of a power-law non-Newtonian polymer melt, through a rectangular slit, similar to the flow over the barrier flight f. The relationships obtained for temperature rise due to heat generated through internal friction allowed the calculus of hht in a given case. Kewords: thermal homogeneity, internal friction, polymer melt

This work presents the results obtained from experiments of rigid PVC stabilization both lead stabilizer and earth alkaline carbonates as co stabilizer. Efficiency of stabilizers was tested by dynamic tests (roll mill processing or Brabender plastograph) and static test (thermogravimetric analysis). Both types of test were in concordance from point of view of stabilization efficiency and from thermal analysis can be predicted the thermal lifetime of PVC products. This is an important fact for durable usage or for recycling products made from PVC. Keywords: PVC stabilizers, roll mill, Brabender plastograph, thermal analysis, lifetime prediction, isoconversional method

In this paper it was established the influence of the processing temperature of the injection moulding on the in-mould pressures and on the characteristics of the obtained items used for high performance sport products. The processed polymers were: polypropylene (PP), polyamide 6,6(PA66), polycarbonate (PC), polyurethane (PU), polyoxymethylene (POM, polyacetal). The injection machine employed was ENGEL G/11/10/116/3 produced in 2002. For the correct temperature measurement in the injection cylinder nozzle a DYNISCO Ti422J thermocouple was used and for the determination of the cavity temperature, a thermocouple 2024T model, produced by Digitron Instrumentation Ltd. was used. The mould cavity pressure was measured with a transducer model IDA, produced by Dynisco Europe GmbH. Keywords: injection moulding, pressure, temperature

The paper argues the necessity of 3-dimensional inspection of injected plastic parts, presenting the special demands and particular condition related to the specificity of part material nature. A measuring strategy on the coordinate measuring machine is presented for verifying the position, dimensional accuracy and shape of the circular holes, slots and the line form for plastic parts used in the automotive industry due to the dimensional changes caused by shrinkage and warpage. The reverse-engineering technique applied in the try-out phase to the production launch is also presented. Keywords: injection, shrinkage, warpage,3-D measurement, reverse engineering

Highly active, new bis(2,6-di- tert-butyl-4-methyl-phenoxy)aluminum methylphosphonate sterically hindered aluminum catalyst was developed for both, homo- and copolymerization of propylene oxide with carbon dioxide. The behaviour of this catalyst compared with that of bis(2,6-di-tert-butyl-4-methylphenoxy)aluminum alcoxide-based catalyst was investigated. The former shows much higher catalytic activity in chemical fixation of carbon dioxide than the latter. According to the experimental data, the unavoidable propylene carbonate resulting in an appreciable proportion in propylene oxide - carbon dioxide copolymerization reaction initiated by sterically hindered aluminum catalysts, seems to appear not at the back-biting reaction of the growing chain. Apparently the reaction temperature or the reaction components molar ratio did not influence the propylene carbonate proportion. Keywords: propylene oxide, carbon dioxide, aluminium catalysts

The paper presents the results of experiments in obtaining some plastic mixtures with high quality characteristics, which should lead to products of complex geometry and improved chemico-structural features, meant to be used in the processing industry-helical milling machining by applying the formation technology in a plastic state. The paper presents the physico-chemical, mechanical and structural features of the mixtures of hard K20 alloys, the compositional networks of the powder making system and of the multi-component organic binder, all these being accomplished according to ICEM’s technical view. To improve the toughness, the tenacity and the wear resistance of the parts devoted to metal working industry, the helical mills were coated with some extra-hard layers by TiC, TiN/Ti2N deposits on hard alloy support by a new PVD technique which supposes a combined magnetron sputtering and ion implantation (CMSII). Keywords: plastic mixtures; helical mills; extra hard layers; magnetron sputtering; ion implantation