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Aromatic diamines are antidegradants with outstanding capability in protection against oxidative and ozone destruction of elastomers and elastomer-based compounds. Their performances are dependent, among others, on their solubility in elastomer matrix and on migration rate to the matrix surface. In an attempt to control solubility and migration of amine antidegradants, the influence of some special additives (fatty amines, fatty amides, ethoxilated phenols) has been investigated and migration characteristics like diffusion coefficient, migration rate and specific migration are presented and discussed. The obtained data correlate in a semi-quantitative manner with main physical characteristics of vulcanizates in circumstances of thermo-oxidative and ozone degradation.

A new set of molecularly imprinted polymers (MIPs), based on acrylonitrile: methacrylic acid (AN:MAA) matrix, selective for diosgenin, was synthesized and characterized. The target molecule, diosgenin, is an important anticancer and antileukemia bioactive compound. The phase inversion method, an emerging and insufficient studied preparation method, was used to prepare 0.5 mm spherical MIPs. Three copolymers of acrylonitrile with methacrylic acid were synthesized by radical copolymerization: AN:MAA 90:10, 80:20 and 70:30 and used for diosgenin imprinting. The imprinted materials were analysed by elemental analysis (EA), attenuated total reflectance infrared spectroscopy (ATR FT-IR), RAMAN spectroscopy, size exclusion chromatography (SEC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and batch rebinding tests. The affinity for the template, expressed as the imprinting factor IF, decreases in the order MIP-AN:MAA-80:20 ] MIP-AN:MAA-90:10 ] MIP-AN:MAA-70:30, meaning that -COOH functional groups have an important role in the imprinting process. Too much methacrylic groups, however, do not exhibit the highest affinity, maybe due to the steric obstruction of methyl groups and to a less stability of the structure by decreasing the AN ratio. Keywords: molecular imprinting, diosgenin, phase inversion, acrylic copolymers, MIPs

This paper presents a usage method of wood waste as sawdust resulting from sawing processes, by achieving hybrid composite materials consisting of epoxy resin reinforced with flax weave fabrics and wood particles. Mechanical characteristics obtained from tensile testing of the material on both directions of the natural fibres weave fabric used as reinforcement are also presented here. New lignocellulosic composite has application to automotive interior components industry, furniture with complex shapes, etc. Keywords: wood sawdust, hybrid composite, weave fabrics, natural fibres, tensile tests, automotive applications

We deduced the equation of motion for free vibrations using Mohr-Maxwell method, considering that the bar is requested to bending by the inertial forces and by the damping forces. We experimentally obtained the dynamic response for sandwich bars with polypropylene honeycomb core, which have the exterior layers made of epoxy resin reinforced with steel fabric. In addition, we determined the damping coefficients per unit mass and per unit length of the bar, for bar with core thicknesses equal to 10, 15 , 20 mm; width of 40 and 60 mm, and the free length of embedded bar equal to 200, 250, 300 and 350 mm. For each type of bar studied, we determined the relationships of exponential type for the calculus damping coefficients (mentioned above), according to the free length of the embedded bar. Keywords: sandwich beam, damping factor, polypropylene honeycomb, free vibrations

The purpose of this paper is to show the possibility of finding the location and to describe internal discontinuities in plates made of plastic materials using non-destructive evaluation methods. Their effect on the mechanical behaviour is also evaluated by means of numerical calculus. The technique of computer tomography („CT”) is used as a non-destructive evaluation method whereas the numerical calculus is realized by the finite element method. Keywords: computer tomography, discontinuity, finite element analysis

The paper refers to the new approach in bone grafting: biomaterials. Many artificial bone substitute materials are currently available for use in orthopaedic trauma surgery. The selection of these materials is more and more difficult as many bone substitute products are now available for use and this method led to a new approach, although the autologus bone grafting still represents the “gold standard” in bone reconstruction surgery. Keywords: bone grafting, biomaterials, reconstruction, fracture

The objective of this paper consists in the minimization of warpage problems which depend on the process parameters during injection molding of thin wall plastic parts using an optimization technique involving Taguchi method, S/N ratio and ANOVA method. For this purpose, a number of experiments are carried out by utilizing the combination of process parameters based on a three-level L9 Taguchi orthogonal array table. To achieve the minimum warpage, the optimum level of process parameters is determined. A drain with 8 sockets is investigated, where melt temperature, mold temperature, injection speed, and packing pressure are selected to be the process variables. The results show that the optimum parameters that can minimize the warpage problem are: melt temperature (190°C), mold temperature (30°C), injection speed (70 mm/s), and packing pressure (55 MPa). The most effective factor on the warpage is packing pressure with a general influence of 55.71%. Keywords: plastic injection molding; thin wall parts; warpage; Taguchi method; S/N ratio; ANOVA method; optimization

The present paper aims to present a method for redesigning plastic products using the Reverse Engineering technique. The originality of this paper stems from its integration of modern scanning techniques and reverse engineering with traditional manufacturing techniques. The paper presents a case study about the redesign of an existing product for which no technical documentation is available, using three distinct phases: reverse engineering, modeling analysis and redesign, manufacturing and testing.. Keywords: redesign, reverse engineering, mould, polymeric material

This study presents new findings of the water/ethanol (ratio) influence on the aniline hydrochloride polymerization process in presence of ammonium persulfate. Water/ethanol mixtures in presence of monomer hydrochloride, as proved by the conductometric, spectrophotometric and refractometric investigations, are far from ideal solutions and promote a partitioned environment , for the polymerization process. By controlling this key parameter (water/ethanol ratio) the polymerization can be shifted from a initial dispersion process to a solution one, followed by precipitation. The associated phenomena revealed modification in terms of conversion, structure (FTIR, UV-VIS), morphology (SEM), thermal stability and doping agent retention (TGA-DTG). Keywords: conductive polymers, aniline hydrochloride, water/ethanol system, polyaniline

The options to deposit chemically a functional composite copper-diamond coating from trilonic electrolyte have been studied with respect to textile polyethylene terephthalate substrate. The optimal basic composition of the electrolyte for surface treatment and the optimal conditions of deposition has been found from the viewpoint of the deposition rate, respectively the thickness of qualitative layer of the copper matrix. A systematic study of the influence of different types and concentrations of surface active agents (SAA) and different temperatures of the electrolyte at continuous air flow stiring has been realized, aimed co-deposition of copper metal-matrix composite, containing diamond particles (sizes, varying within the range 3-70mm). Keywords: coating; fabrics/textiles; surface treatments; metal-matrix composites (MMCs); functional composites