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Branched polymers Dextran‐graft‐Polyacrylamide and Dextran Sulphate‐graft‐Polyacrylamide copolymers with long polysaccharide backbone and various amount and length of PAA‐grafts were synthesised by radical polymerization using Ce(IV)/HNO3 redox system. It was established, that these copolymers have expanded conformation in solution and are able to intramolecular structure formation. Grafting efficiency is conditioned by amount of initiator and Dextran (or Dextran Sulphate) conformation in solution. It was shown that increase in content of copolymer Polyacrylamide component in Dextran Sulphate‐graft‐Polyacrylamide copolymers causes decrease in size of macromolecule due to blocking of polyion charge of main polysaccharide chain by counterions.

In work the opportunity of manufacture of polymeric composite materials of electro technical purpose filled hydrolytic lignin from wood, cotton of peel and rice husks were shown in view of changes occurring in hydrolytic lignin of conditions of reception and processing press composition.

Flexible substrate displays are critical to organic electronics, e‐paper’s and e‐ink’s development. Many different types of materials are under investigation, including glass, polymer films and metallic foils. In this work we report a comparison study of polymer films as flexible substrates for polymer light emitting diodes (PLEDs) technology. The selected polymer substrates are two thermoplastic semi‐crystalline polymers (PET and PEN) and a high Tg material that cannot be melt processed (PAR). Firstly, the chosen films were characterized in morphology and optical properties with the aim to confirm their suitability for optoelectronic applications. Transmittance was analysed by UV‐Vis spectrophotometry and roughness by a surface profilometer. Finally, the surface energy of substrates (untreated and after UV‐ozone treatment) was estimated by contact angle measurements in order to evaluate their wettability for active materials deposition.

The large use of plastics in the world generates a large amount of waste which persists around 200 years in the environment. To minimize this effect is important to search some new polymer materials: the blends of biodegradable polymers with synthetic polymers. It is a large area that needs an intensive research to investigate the blends properties and its behavior face to the different treatments to aim at the biodegradation. The blends used in this work are: some biodegradable polymers such as: poly(hydroxybutyrate) (PHB) and poly(e‐polycaprolactone) (PCL) with a synthetic polymer, polypropylene (PP), in lower concentration. These blends were prepared using an internal mixer (Torque Rheometer), and pressed. These films were submitted to fungus biotreatment. The films analyses will be carried out by Fourier Transform Infrared (FTIR), UV‐Vis absorption (UV‐Vis), Scanning Electronic Microscopy (SEM), DSC and TGA.

The dynamic mean‐field density functional method was applied to the mesoscopic dynamics of block copolymer melts in three‐dimensional lattice model. The analysis of the aggregates and their temporal evolution is studied in free space (PBC) and in confined space. Comparison with experimental system will be given.

Nitrogen oxides play a significant role in chemical processes taking place in an atmosphere and affect on an environment. The researches of the mechanism of nitrogen oxide reactions with polymers are important for evaluation of stability of these materials in polluted atmosphere. These researches can be also used for development of methods of the polymer modification, for example, for preparation of spin—labelled macromolecules. Most important for reactions with polymers are NO, NO2, NO3 as well as NO2 dimers. The features of the mechanism of reactions of these oxides with a number of polymers are considered. The especial attention is given to the mechanism of primary reactions of initiation and intermediate stages of complex radical processes under the action of nitrogen oxides. Nitric oxide does not react directly, but it recombines with free macroradicals formed in polymers by UV photolysis or γ—radiolysis. The nitro compounds formed in the subsequent reactions are converted into stable nitrogen—contai...

A chemical route to produce carbon nanotubes in very mild conditions has been investigated. Nanotubes were obtained by thermal defloruration of polytetrafluoroethylene (PTFE), using Si powder as reductant. The reaction was performed in a quartz‐tube furnace under vacuum. A spongy‐like carbon product was isolated at reaction end which consisted of carbon nanotube embedding the silicon grains. The so obtained carbon nanotubes were characterized by Differential Scanning Calorimetry (DSC), Fourier‐Transform Infrared Spectroscopy (FT‐IR), and Optical Spectroscopy (UV‐VIS), and the morphology was accurately determined by Scanning Electron Microscopy (SEM).

Polymer/clay nanocomposites show macroscopic properties depending on many factors but in particular on the morphology of the of the clay nanoparticles (intercalated, hybrid or exfoliated). The morphology is, in its turn, depending on the polymer/clay affinity and on the processing conditions. The flow involved in the melt compounding is the shear flow that can disaggregate the particles, but is not particularly efficient to induce the exfoliation if there is not a very good adhesion between polymer and clay. In this work we demonstrate that the elongational flow can induce the exfoliation in polymer/clay nanocomposite, even in presence of a very poor affinity between the two components. The mechanical properties are strongly increased both because of the orientation of the macromolecules, but also because of the exfoliation induced by the elongational flow.

Main objective of this research work is to accurately measure and predict in‐plane micro‐deformation and bending of foil‐on‐carrier during lamination and lithographic process. It was demonstrated that lamination of foil on carrier introduced (1) an average in‐plane micro‐expansion of e = 1819±262 ppm independently of foil orientation and (2) bending up to 300 μm, which was strongly related to the foil thickness. Besides this initial in‐plane expansion introduced by lamination, the thermal steps of lithography process introduce additional micro‐deformation to the foil. To be able to predict the micro‐deformation and also time‐dependent behaviour of foil‐on‐carrier, a multi‐mode Maxwell model was employed. The parameters of this model were identified by fitting to the storage and loss moduli measured by DMTA. It was shown that: (1) the used high resolution measurement technique was able to measure in‐plane micro‐deformation of foil fixed on carrier; (2) a classical model for linear viscoelasticity was used ...

Three industrial wastes arising from bleached hardwood kraft pulps, namely: unbleached screen rejects (USR), effluent treatment (ETW), and eucalyptus bark (EB) were analyzed with the aim of their possible valorization as an alternative source of cellulose. Their morphological properties were determined using MorFi apparatus. For this study the sample bleached kraft pulp, BKP, was analyzed as a reference. Lignin and carbohydrate contents were also quantified. These by‐products were studied as such (i.e. without careful purification) because we intended to find rational and low‐cost way of valorization. In fact any additional operation will induce an over cost. The results obtained indicate that these industrial wastes can be potential raw material in fibre‐based applications (paper, composites…), since they contain a high proportion of cellulose with preserved fibrillar morphology. Some of these materials have low lignin and inorganic residue contents.

The influence of relevant replacements of a traditional phosphinate based fire retardant additive with metal oxide nanoparticles on the processability, fire performance and dynamic mechanical properties of a commercial polybuthylene therephtalate resin was investigated. Results have demonstrated that the addition of 2 wt% of iron or antimonium oxide nanoparticles with a simultaneous significant reduction, from 20 wt% to 8 wt% or also to 5 wt%, of a phosphorous based fire retardant (Exolit OP1240) concentrations deals to a clear improvement of the matrix processability by lowering its shear viscosity while maintaining fire performances of products. Dynamic‐mechanical measurements showed an increase of the material stiffness, especially in presence of iron oxide nanoparticles, no effect on the glass transition temperature of the matrix and a widening and raising of loss modulus signals as a sign of more heterogeneous structures formation.

The current work focuses on the testing of a novel material used as an adhesive film in Composite Patch Repair (CPR). A series of Differential Scanning Calorimetry (DSC) results along with various curing cycles not only led to the optimum material composition but also demonstrated the compatibility to the composite pre‐impregnated patches. This in turn was subjected to mechanical testing including shear strength measurements. The substrate was chosen to be 2017 T4 aluminium alloy which is customarily used in the aerospace industry, taking into account that CPR is a technique mainly applied in this field. The subsequent surface preparation of the specimens was investigated for the specified context resulting to the selection of the Ferric Sulphate Sulphuric acid etching process. Finally, a series of specimens representing actual skin repairs were created and subjected to cyclic loading, specifying the suitability of the novel material, compared to commercially available materials.

Hyperbranched polymers are highly cascade branched polymers easily accessible via one‐pot procedure from ABm type monomers. A key property of hyperbranched polymers is their molecular architecture, which allows core‐shell morphology to be manipulated for further specific applications in material and medical sciences. Since the discovery of hyperbranched polymer materials, an increasing number of reports have been published describing synthetic procedures and technological applications of such materials, but their physical properties have remained less studied until the last decade.In the present work, different esterified hyperbranched polyglycerols have been prepared starting from polyglycerol precursors in presence of acetic acid, thus generating functionalization degree with range from 0 to 94%. Thermal analysis of the obtained samples has been studied by Differential Scanning Calorimetry (DSC). Dielectric Spectroscopy measurements have been analyzed by combining loss spectra deconvolution with the mod...

PVB sheet (type Butacite 3GO) with polymer chains containing butyraldehyde, hydroxyl‐ and small amount of acetate groups, was tested. These sheets were highly plasticized, with the content of plasticizer 28%. Studied material was tested at different kneading conditions; especially the influence of temperature, oxygen, mechanical energy and created heat of dissipation was studied.PVB sheet was kneaded at their usual humidity cca 0.5%. Because PVB in known as the material with high hydroscopity, next tests were done on PVB sheets macerated in water. By this operation the humidity of sheets increases to the content 8.0%. High humidity influenced all observed properties. Simultaneously, samples of PVB sheets re‐worked by calendaring and pressing. At the calendaring the sheets were thermally stressed. The calendaring represents shear stress at low temperature. The degradation was evaluated as the change of optical properties, like the light transmittance through the re‐worked material, created haze and yellowi...

The aim of this work was to investigate the foamability of high‐performance polymers (polyethersulfone, polyphenylsulfone, polyetherimide and polyethylenenaphtalate). Two different methods have been used to prepare the foam samples: high temperature expansion and two‐stage batch process. The effects of processing parameters (saturation time and pressure, foaming temperature) on the densities and microcellular structures of these foams were analyzed by using scanning electron microscopy.

It is well known that ionizing radiation can initiate polymerization of suitable monomers for many applications. In this work an epoxy dlfunctional monomer has been used as matrix of a carbon fibre composite in order to produce materials through gamma radiation, for aerospace and advanced automotive applications. Radiation curing has been performed at different absorbed doses and, as comparison, also thermal curing of the same monomer formulations has been done. Furthermore some Irradiated samples have been also subjected to a post Irradiation thermal curing in order to complete the polymerization reactions. The properties of the cured materials have been studied by moisture absorption isotherms, dynamic mechanical thermal analysis and mechanical flexural tests. © 2008 American Institute of Physics.

The aim of the present research was to investigate the replacement of glass fibers with hemp fibers for applications in the piping industry. The choice of hemp fibers was mainly related to the needs, expressed by some companies operating in this sector, for cost reduction without adversely reducing the performances of the pipes. Two processing techniques, namely hand lay up and light RTM, were evaluated. The pipe selected for the study was a curved fitting (90 deg.) flanged at both ends. The fitting must withstand an internal pressure of 10 bar and the presence of acid aqueous solutions. The original lay-up used to build the pipe is a sequence of C-glass, glass mats and glass fabric. Commercial epoxy vinyl ester resin was used as thermoset matrix.Hemp fibers mats were selected as potential substitute of glass fibers mats because of their low cost and ready availability from different commercial sources. The data obtained from the mechanical characterization were used to define a favorable design of the pipe using hemp mats as internal layer. The proposed design for the fittings allowed for a cost reduction of about 24% and a weight saving of about 23% without any drawback in terms of themore » final performances.The light RTM techniques was developed on purpose for the manufacturing of the curved pipe. The comparison between hand lay up and light RTM evidenced a substantial cost reduction when light RTM was used.« less

Adding small amounts of organomodified clay represents an innovative approach to tailor the morphology and properties of immiscible polymer blends. In a recent paper we have found the unexpected formation of a co‐continuous morphology in a blend of high‐density polyethylene and polyamide 6 filled with organoclay. This results in enhanced mechanical properties as a consequence of the synergism among the reinforcement effect of the filler and the dual phase interconnectivity characteristic of co‐continuity. In this work we focus on this topic by investigating the morphology and mechanical properties of blends constituted by low‐density polyethylene and polyamide 11 filled with small amounts of organomodified clay. We show that the filler promotes a finely interpenetrated microstructure, which results in enhanced mechanical properties due to an efficient stress transfer among the phases.

Researches involving ecofriendliness materials are growing up, as well as, a current interest in developing materials from inexpensive and renewable resources. Vegetable oils show a number of excellent properties, which could be utilized to produce valuable polymeric materials. In this work is described the synthesis of polymeric materials from linseed oil (Linum usitatissimum L.) and passion fruit oil (Passiflora edulis) and their characterization by thermogravimetry (TG), differential scanning calorimetry (DSC) and Raman spectroscopy. The TG curve shows that those polymeric materials present two stages of decomposition. DSC plots of the vegetable oils showed some endothermic and exothermic transitions which are not present in the DSC curves corresponding to oil‐based polymers. The Raman spectra of the polymers indicate declining of absorbance in the region of C = C stretching (∼1600 cm−1). This absorption was used to estimate the degree of polymerization (79% and 67.5% for linseed and passion fruit oils...

Mechanical and thermo‐physical properties of composites materials with thermoplastic matrix (PEEK/IM7, TPI/IM7 and PPS/IM7) used for aerospace applications have been analyzed as function of two different process techniques: compression molding and fiber placement process “hot gas assisted.”

The aim of the present work is to analyze bubble stability in the film blowing processing of copolyamide based nanocomposites and to investigate the effect of uniaxial film drawing on nanostructure and final properties. Nanocomposite films with different loadings of nanoclay were produced by film blowing equipment and collected at different draw ratios. Oxygen barrier and mechanical properties of the films were investigated and correlated to the resulting nanomorphology and polymer crystal structures.

Silver‐ultrahigh molecular weight polyethylene nanocomposite prepared by metal‐vapour synthesis has been studied by XPS and TEM.

This study investigates the mechanical, thermal and morphological behavior of coconut flour/polyethylene composites, with special interest on the influence of the surface modification of coconut flour and the presence of different coupling agents on the interfacial bonding. The different treatments of the composites with an EAA copolymer, with titanate, with 5 and 18 wt% of NaOH and acetylating, confirm the better tensile behavior of these composites.

We explored the modification of polymeric film conductivity by changing the conducting filler percentage in the frame of the percolation theory. The polymeric film is a polystyrene (PS) matrix, while the fillers are gold nanoparticles capped with 1‐dodecanethiol (Au‐DT NPs) and small conjugated molecules 8‐ hydroxyquinoline (8HQ). Experimental results show, that increasing the Au‐ DT and 8HQ wt%, film conductivity increases by up to three orders of magnitude due to charge transfer in the 3D network composed by Au‐ DT NPs and 8HQ.

The strain recovery behaviour of an epoxy resin and of an epoxy‐layered silicate nanocomposite deformed at high nominal strain levels (50%) was investigated in isothermal recovery experiments. By representing the whole recovery process in terms of strain recovery master curves, it was possible to evidence differences in the recovery features of the two materials. Further, the study of the energy stored in the materials and of its release process permitted to distinguish the part of recovery occurring with heat release from that occurring after that all the stored energy is released.

In this work, the effect of the frequency of a sinusoidal applied load on the fatigue crack propagation (FCP) behaviour of a polyamide 6 (PA6)/organo‐clay nanocomposite, and its corresponding neat PA6, was investigated via FCP tests carried out at a non‐zero mean stress. An attempt at elucidating the role played by the mean stress (creep) in the fatigue fracture process of the two materials was done. In particular, from FCP data obtained at the various frequencies, a creep contribution to the fatigue fracture propagation was indirectly evaluated and compared with that experimentally measured in creep crack propagation (CCP) experiments.

Two series of Dextran‐graft‐Polyacrylamide copolymers with polysaccharide backbone having different molecular weights (Mw = 20 000 and Mw = 70 000) and long grafted Polyacrylamide chains were synthesized by radical copolymerization using Ceric‐ion‐induced redox initiation. A certain fraction of ionic sites was introduced into the PAA grafts by alkaline hydrolysis during different time periods (NH2 groups were changed by OH groups) in order to convert D‐g‐PAA into polyelectrolyte. It was established that D‐g‐PAA copolymers both in non‐ionic and in ionic form can adsorb transition metal ions from aqueous solution. These copolymers have high flocculation efficiency due to their expanded conformation in water solution. The flocculation ability is inversely related to the spacing of the PAA grafts (i.e. the length of backbone between the grafts).

The effect of cross‐linking of blends on the stability of positive temperature coefficient (PTC) and the elimination of negative temperature coefficient (NTC) were investigated. Linear low density polyethylene (LLDPE) was chemically cross‐linking with various amounts of dicumyl peroxide (DCP). The resulting of cross‐linking structure of composites was analyzed by gel content, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). By the effect of DCP, not only a high PTC intensity appeared, but also was the NTC effect of the composite eliminated. The PTC intensity reached six orders of magnitude for the LLDPE/DCP(0.10 wt%)/CB/Al(OH)3 composite, and successfully passed the test of over‐voltage resistance.

The aim of this work is to propose a design approach for a multifunctional hybrid composite material that integrates high damping performances while withstanding the required structural features. Hybrid composite consists in a three phases composite where a viscoelastic material is added to the conventional structural long fibers/polymeric matrix laminate. Design addresses the problem of integrating the viscoelastic material within the laminate architecture to exploit its maximum damping efficiency. Key aspect is the definition of a viscoelastic multiscale model starting from the constituents to the lamina, and further to the hybrid laminate properties.An analytical procedure has been developed that uses the strain energy method to evaluate the specific damping capacity for all dimensional scales and classical lamination theory was extended to include the transverse shear effects. The method potentiality has been tested against experimental data from Literature. Possible configurations of hybrid laminates have been simulated where viscoelastic material is added as laminae or distributed as long fibers within the structural laminate.

Multiwall carbon natotubes (MWCNTs) were studied as reinforcing filler in a natural rubber based formulation as partial replacement of carbon black [1]. The reinforcing effect exerted by the addition of MWCNTs was dramatic.Using the Enstein‐Gold‐Guth equation the reinforcement has been evaluated quantitatively and it has been shown that it derives from the anisotropy factor f (or shape factor) of MWCNTs used in the present work. In fact f reaches the value of 52.5, one order of magnitude higher than a reinforcing carbon black where the shape factor f is ∼6.

Hygro‐thermal ageing of polymer matrix composite materials is a major issue for all the aeronautical structures. For carbon‐epoxy composites generally used in aeronautical applications the major effect of ageing is the humidity absorption, which induces a plasticization effect, generally decreasing Tg and elastic moduli, and finally design allowables.A thermodynamical and kinetic study has been performed, aimed to establish a program of periodic heating of the composite part, able to reversing the ageing effect by inducing water desorption. The study was founded on a simple model based on Fick’s law, coupled with a concept of “relative saturation coefficient” depending on the different temperature of the composite part and the environment.The behaviour of some structures exposed to humidity and “reverse aged” by heating has been virtually tested.The conclusion of the study allowed to issue a specific patent application for aeronautical structures to be designed on the basis of a “humidity free” concept wh...

The defect diffusion model (DDM) has been used to explain a wide variety of experimental results [1–4]. This includes the electrical relaxation time, electrical conductivity and viscosity of various materials above the glass transition temperature, Tg. In each case the pressure, temperature and volume variation of the physical property was calculated. In the present note, it is shown how the formalism can be used to account for the electrical relaxation time data of Heinrich and Stoll [5] for PVAc. In addition, the analysis is extended to the ratio of the isochoric activation energy to isobaric activation enthalpy known as Ev/Ep or Ev*/H* which elucidates the contributions of volume and temperature to the electrical relaxation time.

In work is shown, that introduction loading on the basis of industrial screenings such as phosphoslag, phosphogypsum and withdrawal Mardjanbulak gold‐mining of factory the incorporating sets oxides of metals positively influence on anticorrosive, physical and strength of property of the investigated composite materials on basis epoxy of pitch [1–4].

The Argon (Ar) plasma pretreated high‐density polyethylene (PHDPE) was blended with the nano‐degree conductive carbon black (CB) and magnesium hydroxide (Mg(OH)2) to formed the over‐voltage positive temperature coefficient (PTC) composite. Effect of the CB content, plasma treatment time, power of plasma, initiator (dicumyl peroxide, DCP), and dosage of 60Co Y‐ray irradiation on PTC behaviors of composites were studied. The results showed that the CB dispersion could be increased with increasing the amount free radicals of PHDPE and then not only the room‐temperature volume resistivity of composite decreased, but also the PTC intensity of composite increased. The best plasma treatment condition was 20W, 1min. As the initiator was added into PHDPE composites and passed the 60Co Y‐ray radiation, the negative temperature coefficient (NTC) effect of composites was eliminated, the PTC intensity of composite markedly increased and composite passes over‐voltage resistance test.

In this work, the nucleating ability of different micro and nano sized nucleating agents for the foaming of thermoplastic biodegradable semi‐crystalline polymer will be reviewed. In particular, the efficiency of the nucleating agent in inducing the formation of the gaseous phase will be compared to the efficiency in inducing the formation of the crystalline phase. In effect, in foaming of semi crystalline polymers, bubble nucleation and crystal nucleation are concurrent and somehow conflicting phenomena.

Blending two different immiscible polymers is one of the most efficient strategies to prepare materials with improved performances. Recently, this multi-phase systems have been used in tissue engineering aiming at the preparation of porous scaffolds for cell culture. In this study, thermoplastic biodegradable and biocompatible multi-phase blends with co-continuous micro-structures have been prepared by melt mixing poly(s-caprolactone) (PCL) with thermoplastic gelatin (TG), a thermoplastic material prepared by mixing gelatin with glycerol. The blend have been prepared by selecting the composition into the 60/40 to 40/60 wt-% PCL-TG range. Dynamic mechanical analysis was performed in order to asses the achievement of an heterogeneous micro-structure while, gravimetric measurements and scanning electron micrograph analysis, performed after the selective extraction of the different phases, were used to evaluate the co-continuity of the different systems prepared. Finally, the PCL/TG blends have been further processed by the gas foaming technique, in order to create porous materials with well controlled open-pore micro-architectures, suitable as 3D porous scaffolds for tissue engineering applications.

This work describes a new algorithm of interconversion between mechanical and dielectric measurement. Another version of this algorithm has been proposed in a previous paper [1], starting from a scaling relation between the translational and rotational viscositieś, which is assumed in a glass forming liquid near the glass transition temperature.In order to improve the previous procedure, the following modifications have been made: 1) a new definition of the complex rotational viscosity in terms of a fractional power, 2) the complex translational viscosity is taken as a non‐Newtonian one, 3) the modulus and phase angle of viscosities were analyzed instead of real and imaginary viscosities and 4) the characterization of the α dielectric relaxation has been carried out by means of the dielectric retardation time spectrum.It is usual that the α and secondary relaxation processes are overlapped in the dielectric and mechanical spectra. Both types of processes have distinct physical basis and different molecular dynamic. For this reason, in the calculation of the mechanic properties using dielectric measurement, and vice versa, it is necessary to consider the α‐ relaxation band separated from the secondary one.

In this work, polymer layers used in the fabrication of chemical sensors are characterized by means of an optical method based on white light interferometry. The study focuses on poly (hydroxy ethyl methacrylate) (PHEMA) and on nanocomposite Carbon black/PHEMA layers commonly used in chemical sensor technology for VOCs measurements. The response of nanocomposite PHEMA/CB layer upon exposure to vapour solvents is investigated in terms of film expansion and compared to the swelling properties of the PHEMA layer.

The thermal oxidation of additive free hydroxyl‐terminated polybutadiene (HTPB) isocyanate crosslinked rubber bulk samples has been studied at 80, 100 and 120 °C in air. The oxidation kinetics has been monitored by gravimetry and thickness distribution of oxidation products was determined by FTIR mapping. Changes of elastic shear modulus G’ during oxidation were followed during oxidation at the same temperatures. The kinetic model established previously for HTPB has been adapted for bulk sample oxidation using previously determined set of kinetic parameters. Oxygen diffusion control of oxidation has been introduced into the model. The mass changes kinetic curves and oxidation products profiles were simulated and adequate fit was obtained. Using the rubber elasticity theory the elastic modulus changes were simulated taking into account the elastically active chains concentration changes due to chain scission and crosslinking reactions. The reasonable fit of G’ as a function of oxidation time experimental c...

The photo‐oxidative degradation of a densely cross‐linked epoxide/diamine network based on tetraglycidyl‐4,4’ diaminodiphenylmethane (TGDDM) and 4,4’ diaminodiphenyl sulphone (DDS) has been investigated by FTIR spectroscopy, dynamic‐mechanical thermal analysis (DMTA) and compressive mechanical tests. The FTIR measurements allowed us to monitor the degradation process of the several groups present in the TGDDM/DDS network and to obtain reliable kinetic data. On this basis the most likely photo‐degradation mechanisms were proposed, and the main pathways through which the degradation reaction proceeds were identified. Dynamic‐mechanical measurements and mechanical tests were used to gain an insight in the effect of the photo‐oxidative degradation on the relaxation processes of the epoxy network and on the mechanical performances.

In work are investigated physico‐mechanical and strengthening property of polymeric compositions from the contents of polythene, oligomer E‐181 and various conditions of influence on theme physical factors, is determined the following optimum structures: EIS‐1—100 mas.h., piperidine 7 mas.h., polyethylene 10–15 mas.h., E‐181—20–30 mas.h., which have high physico‐mechanical properties and can effectively protect of process equipments of food manufactures and drinks from influence of various environments.

In this study, a variety of concentrations of chelating agents were added to obtain the anchoring effect and chelating effect in the electroless plating bath. The mechanism of the Cux(x = 1,2)S growth and the electromagnetic interference shielding effectiveness (EMI SE) of the composite were studied. It was found that the vinyl acetate residued in PAN substrate would be purged due to the swelling effect by chelating agents solution. And then, the anchoring effect occurred due to the hydrogen bonding between the pits of PAN substrate and the chelating agent. Consequently, the copper sulfide layer deposited by the electroless plating reaction with EDTA and TEA. The swelling degree (Sd) was proposed and evaluated from the FT‐IR spectra. The relationship between swelling degree of the PAN films and EDTA (C) is expressed as: Sd = 0.13+0.90×e∧(−15.15C). And TEA series is expressed as: Sd = 0.07+1.00×e∧(−15.15C). On the other hand, the FESEM micrograph showed that the average thickness of copper sulfide increase...

The most popular and important biodegradable polymers are aliphatic polyesters, such as polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polyhydoxyalkanoates (PHA’s) and polyethylene oxide (PEO). However, each of these has some shortcomings which restrict its applications. Blending techniques are an extremely promising approach which can improve or tune the original properties of the polymers[1]. Aliphatic polyesters are a central class of biodegradable polymers, because hydrolytic and/or enzymatic chain cleavage of these materials leads to α‐hydroxyacids, which in most cases are ultimately metabolized in human body. This is particularly useful for controlled release devices and for other biomedical applications like suture fibers and ligaments. For aliphatic polyesters, hydrolysis rates are affected by the temperature, molecular structure, and ester group density as well as by the species of enzyme used. The degree of crystallinity may be a crucial factor, since enzymes attack main...

Thermal stability of a glass‐carbon/polyester hybrid composite has been evaluated between 180 °C and 210 °C in different O2/N2 atmospheres under atmospheric pressure by differential calorimetry, gravimetry and optical microscopy. Thermolysis predominates in the carbon core where it induces an efficient chain scission process (catastrophic decrease of Tg) and then, a deep embrittlement (formation of many cracks). On the contrary, thermal oxidation predominates in a thin superficial layer of about 60 μm thick in the glass sock where it inhibits thermolysis. A kinetic model has been elaborated to tentatively simulate mass changes of both constitutive materials and validate a proposal of mechanistic scheme.

Mesoporous silica has been added to Ultem® 1000 polyetherimide using solution casting. The mesoporous silica that was added was either uncoated or coated with polystyrene. Audio frequency dielectric relaxation studies were then carried out over the temperature range 5.5 to 550 K. Several interesting results were obtained. First, the uncoated mesoporous silica caused essentially no change in the relaxation spectrum of pure Ultem®. The polystyrene coated mesoporous silica caused rather large changes. The most striking example is the introduction of a new relaxation. This relaxation occurs at about 150 K and 1000 Hz as showing in fig. 1 via the open circles.

The aim of this study concerns the development of bioresorbable composite materials for bone repair and regeneration. Hydroxyapatite loaded composites were synthesized by a colloidal non‐aqueous chemical precipitation technique at room temperature. This study describes the synthesis and characterization of HA/PCL composite material, in order to verify the interaction between the ceramic and the polymer phases by a morphological investigation.

Mass transport mechanism of low molecular weight compounds (water and carbon dioxide) into polyimide films has been analysed and modelled on the basis of the relevant findings of an in situ FTIR spectroscopic analysis. In particular, in the case of water, it has been assumed that concurrent diffusion occurs of single water molecules and water dimers, which display different mobilities. A non‐linear instantaneous equilibrium between the local concentrations of these two species has been imposed, based on a two layers BET theory. The proposed approach is able to give a good qualitative and quantitative interpretation of both sorption equilibrium and of sorption/desorption kinetics data.

For the first time we suggest a method for making of metal‐polymeric core‐shell nanocomposites, consisting of metal containing core coated with ultrafine poly(tetrafluoroethylene). This approach combines a method of polymer powder modification by supercritical carbon dioxide impulse expansion (Method of Impulse Modification, MIM) with a Metal‐Vapor Synthesis (MVS) for introduction of metal nanoparticles into poly(tetrafluoroethylene).

A novel superabsorbent hydrogel composite based on Collagen have been prepared via graft copolymerization of Methacrylic acid (MAA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The composite structure was confirmed using FTIR spectroscopy. A new absorption band at 1728 cm−1 in the composite spectrum confirmed kaolin‐organic polymer linkage. The effect of kaolin amount and MBA concentration showed that with increasing of these parameters, the water absorbency of the superabsorbent composite was decreased.The swelling measurements of the hydrogels were conducted in aqueous salt solutions.