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The scaling law for relaxation times, τ(V,T) = ℑ(TVγ), recently proposed by Casalini and Roland, is utilized in the framework of KAHR (Kovacs Aklonis Hutchinson and Ramos) phenomenological theory. With this approach it is shown that the Pressure, Volume, Temperature (PVT) data obtained on Poly(carbonate)(PC) can be reliably predicted, in the region of the alpha relaxation, by using only two fitting parameters, namely: the relaxation time in the reference condition, τg, and the fractional exponent, β that describes the dispersion of the alpha relaxation.

The vapor transport properties of nanocomposite materials obtained with different techniques and based on a high free volume glassy polymer suitable for membrane separations, poly[1-(trimethylsilyl)-1-propyne] (PTMSP), have been determined and modeled. The simple mixing in solution of hydrophobic fumed silica nanoparticles with PTMSP leads to mixed matrix membranes, which show higher free volume and higher values of diffusivity and permeability than the pure polymeric material. If a sol-gel route is followed, with PTMSP and Tetraethoxysylane (TEOS) as precursor of the silica phase, one obtains hybrid matrices characterized by lower vapor diffusion and sorption values with respect to the pure polymer. Although the trends observed are very regular functions of the silica content in the composite, none of the behavior observed obeys traditional models for composites permeability, such as the Maxwell’s one. Both types of behaviors were modeled considering the variation of polymer fractional free volume induced by the inorganic phase: in the mixed matrices the poor interactions between silica and polymer chains favor the formation of nanovoids at the interface, increasing the free volume and the vapor diffusivity, while in the more interconnected hybrid matrices the inorganic domains act as constraints, reducing the volume occupied by the polymeric phase, which is naturally endowed with a very high excess free volume.

Acoustic emission source location in a unidirectional carbon-fibre-reinforced plastic plate was attempted employing Artificial Neural Network (ANN) technology. The acoustic emission events were produced by a lead break, and the response wave received by piezoelectric sensors, type VS150-M resonant at 150 kHz. The waves were detected by a Vallen AMSY4 eight-channel instrumentation. The time of arrival, determined through the conventional threshold crossing technique, was used to measure the dependence of wave velocity on fibre orientation. A simple empirical formula, relying on classical lamination and suggested by wave propagation theory, was able to accurately model the experimental trend. Based on the formula, virtual training and testing data sets were generated for the case of a plate monitored by three transducers, and adopted to select two potentially effective ANN architectures. For final validation, experimental tests were carried out, positioning the source at predetermined points evenly distributed within the plate area. A very satisfactory correlation was found between the actual source locations and the ANN predictions.

Glassy polymers confined at nano‐scale do exhibit anomalous thermo‐viscoelastic behavior in respect to their bulk response. For example, in ultra‐thin polymer films both negative coefficient of thermal expansion (NCTE) and glass transition temperature (Tg) depression are observed, experimentally. Theoretical conjectures have been drawn that qualitatively explain some features of highly confined glassy polymers [1,2,3] yet quantitative prediction of NCTE and Tg depression would allow a reliable design of devices operating at nano‐scale. In this paper the thin films anomalies are shortly reviewed and their explanation is tempted with classical existing theories.

Halloysite nanotubes were dispersed in a commercially biodegradable blends by melt compounding. Bionanocomposites based on a film-grade commercial blend of poly(hydroxybutirate)-co-valerate PHBV and poly(butylene adipate-co-therephthalate) PBAT and containg up to 10% by weigth of tubular clays (HNTs) were prepared by using a twin-screw lab extruder and filmed by a film-blowing equipment. Film samples were subjected to thermal and structural investigations. Calorimetric analysis showed that signals shape is clearly affected by the heating and cooling rate, respectively. Structural investigations performed by X-Ray diffraction tests satisfactorily allowed to interpret thermal behavior highlighting the occurrence of different crystalline modifications, depending on the scanning thermal rate, the inclusion of filler and its chemical functionalization.

We prepare well dispersed nanocomposites based on Graphite Nanoplatelets (GNPs) and polystyrene (PS) through a combination of solution and melt mixing techniques. The samples are subjected to morphological, electrical, and rheological investigations. Electron microscopy analyses show that GNPs are well dispersed, and the presence of few nanometers thick GNPs is noticed. The electrical conductivity of the polymer dramatically increases at a critical content of particles of Φ~4 wt.%, indicating that electrical percolation has occurred. The existence of a percolating network induces a marked elastic connotation in the melt state. We show that the elasticity of GNP networks in samples at different composition can be scaled on a single master curve. This allows for the accurate estimation of the rheological percolation threshold. In addition, using the master curve we can infer the elasticity of GNP networks which are too tenuous to be appreciated via conventional rheological measurements.

We have monitored the physical aging of poly(methyl methacrylate) (PMMA)/silica nanocomposites, namely the slow evolution occurring to the structure of glasses below the glass transition temperature (Tg), following the time evolution of the enthalpy as measured by differential scanning calorimetry (DSC). We have systematically varied the concentration of silica to provide insight about the influence of the ratio area of silica/volume of PMMA (Asil/VPMMA) on the physical aging process. Our results clearly indicate that physical aging speeds up with increasing silica concentration. Furthermore, the amount of recovered enthalpy decreases with increasing silica concentration, indicating that part of the enthalpy is recovered during the delay time before the first data are collected.

Thick laminate veneer lumber(LVL) fibre reinforced composites were constructed from the alternated perpendicularly arrayed of peeled rubber woods. Glass woven was laid in between the layers. Native golden teak veneers were used as faces. In house formulae epoxy was employed as wood adhesive. The hand lay‐up laminate was cured at 150° C for 45 mins. The cut specimen was post cured at 80° C for at least 5 hours. The 2k factorial design of experimental(DOE) was used to verify the parameters. Three parameters by mean of silane content in epoxy formulation(A), smoke treatment of rubber wood surface(B) and anti‐termite application(C) on the wood surface were analysed. Both low and high levels were further subcategorised into 2 sub‐levels. Flexural properties were the main respond obtained. ANOVA analysis of the Pareto chart was engaged. The main effect plot was also testified. The results showed that the interaction between silane quantity and termite treatment is negative effect at high level(AC+). Vice versa,...

5th International Conference on Times of Polymers (TOP) and Composites -- JUN 20-23, 2010 -- Ischia, ITALY, WOS: 000283528400019, In this study, a comprehensive laboratory test on 100 mm diameter HDPE 100 polyethylene flexible pipe buried in quartz sand is described. The laboratory test was performed in a 40 mm thick plexiglass-fronted test tank which replicated a classical trench section in field conditions. The polyethylene flexible pipe was positioned against the glass with its longitudinal axis perpendicular to the glass. This allowed direct observation of the backfill-pipe interactions and pipe performance under surcharge loads. Three high definition photogrammetric cameras were taken photogrammetric images through the glass allowing the discrete measurement and image processing of the deformation patterns of the polyethelene pipe conduit during the pipe installation and incremental surcharge loading. Vertical loads were applied in increments of 10 kPa to 150 kPa using air pressure membranes. According to the test results, it is understood that the installation technique and backfill properties have an important effect on circumferential strains, performance and deformation characteristics of polyethelene HDPE pipe. It was also observed that close-range image processing is a very simple and appropriate method for measuring three dimensional pipe deformations under various conditions., Second Univ Naples, Univ Naples Federico II

In this study Polyaniline/polystyrene nanocomposites were prepared in the aqueous solution by using ammonium peroxy disulfate as an oxidant in the presence of poly (vinyl pyrrolidone) as surfactant. Morphology and chemical structure was characterized by using scaning electron micrograph(SEM), fourier transform infrared (FTIR) spectrometer and removal percentage obtained by using mass atomic absorption.

The blending of PET from post‐consumer packaging products with polyolefins can provide toughened materials. PET and polyolefins are immiscible polymers and to the above purpose, different method of reactive compatibilization are investigated to achieve a fine dispersion of polyolefin domains into a PET matrix. The use of a functionalized polyolefin, bearing reactive groups toward PET terminals, is a promising route to obtain grafted copolymers acting as interface stabilizers. In particular the use in the melt blending of ester or hydroxyl functionalized polyolefins in the presence of transesterification catalysts and or anhydride functionalized polyolefins as compatibilizer precursors were both investigated by focusing onto the relevant chemical aspects. The prepared blends were analyzed through suitable fractionation methods, such as selective extractions, and spectroscopic analysis in order to identify the molecular architecture of the PET‐polyolefin copolymers macromolecules resulting from the process and study their effectiveness at the interface region. Moreover the phase morphology and the thermo‐mechanical properties were investigated and correlated to structure of the macromolecular species in the system.

In the last years the role of confinement in selecting conformations of polymers and in accelerating the convergence has been clearly stated. The choice of proper confining systems is crucial in designing new materials. In this contribution, the consequences of tailored mesostructures in controlling a series of physical‐mechanical‐electronical properties are discussed with a particular attention to magnetic materials and photonic crystals.

Epoxy nanocomposites considered as challenging polymeric matrix for advanced reinforced plastics. Nanofillers change rheokinetics of epoxy resin curing, affect wetting and adhesion to aramid and carbon fibers. In all cases extreme dependence of adhesive strength vs filler content in the binder was observed. New experimental techniques were developed to study wettability and fiber‐matrix adhesion interaction, using yarn penetration path length, aramid fiber knot pull‐up test and electrical admittance of the fracture surface of CFRP.

Utilization of soft PVC is restricted by plasticizer migration that can affect material properties, as well as its toxicity. Modifying the chemical structure of PVC is one of the most effective tool to reduce the diffusion of plasticizer. In this work, a soft cross‐linked PVC was obtained using a difunctional amine, namely isophoron diamine (IPDA) as the cross‐linking agent. The gel content (wt %) was evaluated by weighting the insoluble portion obtained through solvent extraction technique. Thermogravimetric analysis (TGA) revealed that cross‐linking reactions promote thermal degradation phenomena in the polymer matrix. Tribological properties of soft uncross‐linked, cross‐linked and rigid PVC were determined. Soft formulations were held in contact for 32 days with rigid PVC sheets. Plasticizer migration towards the interface causes an increase of dynamic friction compared to that of the reference rigid PVC.

Linear hyperbranched block copolymers based on PBA polyesters (HPBA) has been synthesized by a one‐pot synthesis procedure and well characterized by MALDI‐TOF mass spectrometry, H‐NMR and SEC tools, to obtain reliable information on its chemical composition and molar mass distribution.

Thin films of polyethylene have been exposed to thermal and photochemical accelerated agings at different temperatures and different UV intensities. In both cases, mechanical tests performed on aged samples revealed a severe embrittlement of the PE material. However, a multi‐scale analysis showed that i) under thermal oxidative conditions, such embrittlement mainly resulted from a reduction of molecular mobility of the amorphous phase due to annealing phenomena, while ii) it was rather associated to a competition between chain scission and cross‐linking processes under photo‐oxidative conditions. As regards the oxidation mechanisms, it was found that thermo‐oxidation is clearly initiated by a bimolecular decomposition of hydroperoxides, while photo‐oxidation seems rather initiated by the photolysis of ketones and hydroperoxides. Over a critical threshold of the hydroperoxide concentration, thermolysis of hydroperoxides seems to predominate and even to control the overall photo‐oxidation kinetics.

The influence of organo‐clays on the durability of the nanocomposite materials finds expression in the efficiency of stabilizers. With the two kinds of stabilizers tested that are conventionally a processing one with a phenolic function and a long term stabilizer which is a redox antioxidant (hindered amine light stabilizer), the main conclusion is that the presence of organo‐montmorillonite decreases the efficiency of the stabilizer. However, with specific stabilization additives the prodegradant effect of nanoclays can be cancelled and it offers a new insight in the stabilization strategy of nanocomposites.The photochemical study of PP/LDH nanocomposites revealed that the divalent cations of LDH nanofiller (Mg or Zn) have an influence on the durability of the polymer and also on the photostabilization with an opposite behavibour between phenolic and redox antioxidants.

Nanocomposite films based polyaniline and polystyrene sulfonate (PANI:PSS) were prepared and characterized by chemical oxidative polymerization. Transparent and uniform films were obtained by spin‐coating onto patterned ITO‐coated glass substrates and were used as hole injection layer (HIL) in OLED devices. The devices made with HIL‐based PANI:PSS were compared with those with only ITO and showed better electrical characteristics, lower turn‐on voltage and a three time improved device efficiency.

This work focuses on the possibility of improving performance properties of polylactide films for packaging applications by melt mixing silicate nanoparticles within PLA matrix. Nanocomposites at various silicate loadings were produced by cast‐film extrusion using two different temperature profiles. Oxygen barrier and mechanical properties of the produced films were investigated and correlated to their nanostructure through analytical techniques sensitive to different aspect of the same morphology, such as TEM, XRD and rheological analyses.

A series of regio‐random poly(3‐alkyl thiophenes) containing C = 6–12 carbon atoms per side chain is studied using shear, calorimetry and x‐ray scattering methods. Dynamic and structural data indicate a nanophase separation of thiophene main chains and alkyl groups. Alkyl nanodomains of size of 1–3 nm are formed as indicated by pre‐peaks in scattering data at 0.2A−1≤q≤0.6A−1. Apart from the conventional α relaxation, an additional αPE process appears at low temperatures reflecting an independent dynamics within the alkyl nanodomains. The influence of slow side chain crystallization and densification processes during physical aging below Tg on the relaxation behavior is studied. Long term experiments show that short alkyl groups do not crystallize, whereas for longer alkyl groups, side chain crystallization is occurring but hindered by immobile and rigid main chains. Slow side chain crystallization processes are indicated in poly(3‐decyl thiophene) and poly(3‐dodecyl thiophene) by melting peaks in DSC scan...

We present a relatively simple method for analyzing H content on surfaces of selected commercially available polymers, i.e. polyethylene, polypropylene, polystyrene, and poly(methylphenylsilylene). The applied method, i.e. the Elastic Peak Electron Spectroscopy (EPES), is based on quasi‐elastic scattering of primary beam electrons with atoms of solid sample constituents. Electron energy, scattering angle and difference between electron mass and atomic mass of sample constituents induces an electron recoil energy loss. Recoil effect results of splitting the elastic peak into components, by their energy shifting and broadening. For above‐mentioned polymers, the EPES method indicates the surface H content close to the nominal composition. Sampling depth of the method does not exceed inelastic mean free path of electrons used in the scattering experiment. Therefore, the technique is useful to monitor H surface content during or after various surface modifications as UV, electron and ion beam modification of polymer surfaces or surface plasma treatments. Limitations of the technique are mentioned.

Reported nanocomposites of poly(vinyl chloride) have been prepared using bentonite‐based clay, Na‐montmorillonite (nature clay) and organophilic clay 30B. Polymer nanocomposites of differing compositions were produced using Buss KO‐kneader via melt intercalation method. The effect of different type of plasticizer (both low molecular and high molecular) and compounding conditions on the structure of PVC/clay nanocomposites was investigated. Different compounding conditions were tested to study their influence on nanoparticles dispersion, orientation and exfoliation in PVC/clay nanocomposites. The structure of PVC/MMT nanocomposites was observed using X‐ray diffraction, transmission electron microscopy (TEM) and AFM (Atomic Force Microscopy). It was found that the Na‐montmorillonite offer low exfoliation level, while 30B modified by plasticizer exhibits fine dispersion of partial to nearly full exfoliated MMT. Moreover the processing conditions play also important role in nanocomposite production.

In this work the protective efficacy and stability against UV weathering of polymeric nanocomposites for concrete (CLS) surface protection have been evaluated. In particular, nanocomposite hybrids were prepared dispersing a commercial organomodified montmorillonite (Cloisite 30B) in two different polymeric matrices, one based on fluoroelastomers (Fluoline CP), the other on silane and siloxane (Antipluviol S). The obtained systems were characterized by several techniques (SAXD, DSC, TGA, FT‐IR, contact angle measurements, colorimetry), before and after accelerated aging due to UV exposure, in order to evaluate the effect of the nanoscale dispersion of the organoclay on the properties and the UV stability of the treatments.

The influence of nanosized calcium carbonate on the gelation process, thermal stability and mechanical properties of rigid poly(vinyl chloride) has been studied. The gelation time of rigid PVC/calcium carbonate nanocomposites depends on the percentage and superficial treatment of CaCO3. The results of thermogravimetric analysis underline an improvement of the thermal stability as a function of the surface modifier. Finally, the flexural modulus, the flexural strength as well as the critical stress intensity factor increase with the addition of poly(acrylic acid) (PAA) or poly(butadiene-co- acrilonitrile-co-acrylic acid) (PBAA) coated nanoparticles.

A series of biostable polyurethane (PU) formulations, including a composite containing a biocompatible clay as filler, were prepared as new biomaterials for cardiovascular applications. Polydimethylsiloxane (PDMS) and polytetramethylenoxide (PTMO) were selected as macrodiols because of their high hydrolysis resistance. 1,6‐Diisocyanatohexane (HDI) and 1,4‐cyclohexane dimethanol (CDM) were used as diisocyanate and chain extender, respectively. Chemical and mechanical characterizations of the obtained polymers highlight that they are promising materials for applications in the cardiovascular field.

The thermal degradation of high density polyethylene (PE) films, stabilized by a common commercial synergistic blend of antioxidants, were studied at 120, 140, 150 and 160° C in air under atmospheric pressure. Antioxidants depletion has been monitored by UV and FTIR spectrophotometry and induction oxidation time measurements. The peculiar shape of kinetic curves suggests that the physical loss of antioxidants cannot be neglected, but also that classical evaporation‐reaction models are inadequate to predict such a kinetic behavior. A model assuming the existence of two distinct antioxidant phases in equilibrium into the PE matrix is tentatively proposed. The insoluble (dispersed) phase, corresponding to the antioxidant excess relatively to the solubility threshold, supplies in antioxidant the soluble phase, until its complete exhaustion, whereas the soluble phase evaporates and is consumed by the chemical reaction.

The interlaminar toughening of a carbon-fibre reinforced composite by incorporation of electrospun polyvinylidene fluoride (PVDF) nanofibrous membranes was explored in this work. The nanofibres were electrospun directly onto commercial pre-impregnated carbon fibre materials under optimised conditions and PVDF was found to primarily crystallise in its β phase polymorphic form. There is strong evidence from DMTA analysis to suggest that a partial miscibility between the amorphous phases of the PVDF nanofibres and the epoxy exists. The improved plastic deformation at the crack tip after inclusion of the nanofibres was directly translated to a 57% increase in the mode II interlaminar fracture toughness (in-plane shear failure). Conversely, the fracture toughness in mode I (opening failure) was slightly lower than the reference by approximately 20%, and the results were interpreted from the complex micromechanisms of failure arising from the changes in polymorphism of the PVDF.

In the present work the thermal characterization of composites of polylactide (PLLA) with pristine or functionalized multiwalled carbon nanotubes (MWCNTs) prepared by the method solution mixing. The effect of % MWCNTs added on the thermal transitions was evaluated.

Epoxy nanocomposites with ceramic nanoparticles, i.e. Al2O3, Tio2 and SiO2, were prepared by combined dispersion techniques, namely mechanical mixing and sonication. The influence of fillers addition on thermal, mechanical and dielectric properties have been investigated by means of Differential Scanning Calorimetry (DSC), Dynamic‐mechanical analysis (DMA) and dielectric spectroscopy to measure the dielectric permittivity, tan δ and volume resistivity. Morphological investigations by Scanning Electron Microscopy (SEM) has been also performed.

This paper presents the analysis of time‐dependent behavior of polymeric material under cyclic loading, modeled with the tooth‐like loading conditions in terms of the shear stress that are determined by the operating frequency and the ratio between unloading and loading phase within one loading cycle. Assuming viscoelastic behavior of the material, the intensity of strain accumulation process is analyzed regarding the effects of the operating frequency, and number of loading cycles for series of time‐dependent material properties expressed with discrete retardation spectrum. Results show that by knowing spectrum distribution of the time‐dependent material property we may predict the critical operating frequencies that may lead to the highest level of accumulated strain.

Nanocomposite solutions formed of Poly [(9,9‐diesilfluorene)‐(2,7 diyl)‐alt‐(2,5‐dimetil‐1,4‐phenilene)] and highly luminescent nanocrystals of CdSe coated with a shell of ZnS (CdSe@ZnS) with different size have been obtained by using a common solvent and characterized by means of absorption and emission spectroscopy. Viscosity has been investigated, in order to prove the suitability of the inks for the printing processing. The homogeneous nanocomposites have been precisely dispensed by ink‐jet printing, using drop‐on‐demand mode onto glass substrates. The deposited micro‐scale pixels have been morphologically characterized by means of fluorescence microscopy, 3D profilometry and Atomic Force Microscopy (AFM). The results demonstrate that the spectroscopical properties of the components have been effectively conveyed to the final nanocomposites, retaining the size dependent feature of the inorganic moiety, and providing a suitable ink with for fabricating reproducible microstructures.

Polyols derived from renewables resources are good candidates to obtaining segmented polyurethane elastomers. Diisocyanates with different chemical structure, aliphatic and aromatic, have been used to synthesize by a two step polymerization procedure polyurethane elastomers with different hard segment content. Microphase separation and thermal stability have been studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The analysis of the H‐bonded and non H‐bonded urethane carbonyl stretching vibration in the amide I region, the glass transition temperature of the soft and hard segments and the melting temperature and enthalpies of hard segment reveal that aliphatic diisocyanate based polyurethanes present higher phase separation degree and harder segment crystallinity and also superior thermal stability than aromatic diisocyanate‐based polyurethanes.

We report on the synthesis and the characterization of a new class of segmented polyethers POC containing the oxadiazole and carbazole units. The polymers exhibit a high thermal stability, high glass transition temperatures and good solubility in common organic solvents, despite the extended aromatic portion in the main polymer chain. According to previous reports on oxadiazole/carbazole containing materials, POC show high photoluminescence activity in the blue region of the visible spectra. The good solubility in chlorinate solvents allows the preparation of films with homogeneous thickness by spin coating. Glass transition temperature in the range 115–125° C ensures good stability of film morphology at room temperature. For these features, polymers POC are potential candidate materials for fabricating blue light emitting devices.

High performance polymer based‐cements (i.e. cements having a water to cement ratio, w/a, close to 0.1) almost totally free of defect, have been developed in recent years claiming a great interest for their very high tensile strength compared with traditional cements. These materials can be produced utilizing very simple unit operations and further formed in complex shapes with high surface quality. Indeed these materials have the disadvantage of being too much brittle and for this main reason they are rarely utilized in practice. Toughening the Macro Defect Free Cements (MDF) implies the strict control of the structure. The structure is governed by the process‐induced paste modifications. In this paper we show that toughening can be achieved with elastomeric particles having well defined size distribution and physico‐chemical characteristics in relation with both the binder polymer and the cement chemistry.

The present work is focused on study of “green composites” elaborated from thermoplastic starch (TPS) as polymer matrix and a fiber from natural origin (rush) as reinforced fiber. The effect of the fiber content has been studied by means of the mechanical properties. The composite resulting presents a lack of interaction between matrix and fiber that represents a performance decrease. However the biodegradability behavior of the resulting composite raise this composite as useful an industrial level.

Poly(vinyl alcohol) (PVA)/platinum composite nanofibers were successfully prepared by the electrospinning method. Water‐based colloidal platinum in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic‐inorganic composite nanofibers. The PVA/platinum composite nanofibers were characterized by field emission scanning electron microscopy (SEM).

Polyacrylonitrile/titania (PAN/TiO2) nanofibrous mats were prepared by an electrospinning method and silver nanoparticles were deposited by electron beam (e‐beam) irradiation of silver ions in aqueous solutions. The morphology of the electrospun fibers was characterized by SEM analysis. The deposition of silver particles was not of a uniform coverage on the PAN/TiO2 surface, but of a heterogeneous growth of the silver particles on the PAN/TiO2 surface. The photocatalytic efficiency of the composites against methylene blue dye in an aqueous solution improved and the actibacterial activity against E. coli and S. aureus was found to increase with the silver nanoparticles being induced.

The objective of this study was to achieve an in‐depth understanding of the role of the nanoparticles in modifying the sliding wear behavior of SFRPs. In particular, the effects of nanoparticles on the contact mechanics and the wear behavior of the transfer film were investigated. It was found that the additional nanoparticles do not directly contribute to the formation of a high performance transfer film. However, the presence of nanoparticles in the contact region can effectively reduce the adhesion between the transfer film and the polymeric specimen, resulting in a lower coefficient of friction. In particular, the rolling behavior of nanoparticles can significantly enhance the tribological performance of SFRPs, especially under extreme sliding conditions.

The monolayer of a diblock copolymer was studied by Brewster Angle Microscopy (BAM) during compression, which allowed the estimation of the collapse pressure πc of the polymeric system. Molecular Dynamic Simulation (MDS) was performed in order to explain the experimental behavior of the functionalized poly(methacrylate)s studied at the air‐water interface.

Melt blended compounds based on a film grade thermoplastic polyurethane resin filled with relatively low contents of multiwalled carbon nanotubes have been investigated. Materials, prepared through the production of a masterbatch containing 3 wt% of nanotubes and subsequent dilution of the same by addition of matrix pellets, were analyzed in the form of tapes and films always taking the neat matrix, processed in the same conditions, as the reference. Improvements of the matrix extrudability and mechanical benefits showed for all investigated composite samples have been satisfactorily interpreted by morphological observations carried out in both transmission and scanning electron microscopy.

The use of polarization‐sensitive optical coherence tomography for monitoring the progress of a classical shear experiment in a slit die leads to new insights in the mechanisms of polymer crystallization. For the first time it is possible to get both depth and time resolved information on the development of different layers as a result of the processing conditions. By additionally measuring the transmitted light the method is at the same time fully compatible to conventional birefringence measurements. Microscopic analysis of the extruded stripes completes the description of the crystallization process.

The crystallization behavior of homopolymer Poly(ethylene oxide) PEO and block copolymer Poly(2‐vinyl pyridine)‐b‐poly(ethylene oxide) (P2VP‐b‐PEO) blends was investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM), thermogravimetric analysis (TGA) and atomic force microscopy (AFM). Different compositions of two homopolymer/block copolymer blends were studied. The formation of the spherulites was observed for the systems in study by POM. A diminishing of the growing rate of spherulites G (μm/s) for these blends can be observed as the copolymer content increases.

In the last years, a remarkable increase in the use of nanoparticles as fillers of polymer materials has been detected. It is mainly due to the excellent properties that these materials can provide when added to polymer matrices as a consequence of the high specific surface, so that, small additions can lead to a remarkable increase in overall properties. Small additions of carbon nanotubes (CNTs) in a polypropylene matrix promote an increase in mechanical and thermal performance. Presence of CNTs leads to formation of interlock points with polypropylene chains and this has a positive effect on mechanical properties; thus an increase in elastic modulus and tensile strength are obtained for relatively small amounts of CNTs in the 1–3 wt.%. Regarding thermal properties, it is important to note that a remarkable increase of thermal stability is detected at medium temperatures (oxidation onset measured by differential scanning calorymetry) and high temperatures (degradation measured by thermogravymetric analysis). So, we can conclude that the use of small additions of CNTs is a useful technique to improve polypropylene performance from both technical and economical point of view since good balanced properties are obtained. Furthermore, the cost of these nanoparticles has decreased considerably in the last years and.

For modern application in microoptics the refractive index of polymers can be adjusted in a certain range by the addition of electron‐rich organic dopants. As an unwanted side‐effect a pronounced plasticizing occurs. In this work the addition of a crosslinker (divinylbenzene) to the unsaturated polyester matrix, doped with phenanthrene for refractive index adjustment, allows for a successful suppression of the plasticizing effect measured after polymerization. Even at high phenanthrene concentrations the glass transition temperature of the initial polymer could be almost retained. An increase of the polymers refractive index from 1.5684 up to a value of 1.6425 could be achieved.

Epoxy-clay nanocomposites were prepd. dispersing both pristine and functionalized sodium montmorillonite powders (1 and 3 wt%) in epoxy resin by means of sonication and sonication/ball-milling high energy mixing processes. Silylation reaction of sodium montmorillonite (Na-MMT) was performed by using 3-aminopropyltriethoxysilane (A1100) and N-2-aminoethyl)-3-aminopropyltrimethoxysilane (A1120) as coupling agents. Morphol. investigations showed that the MMT stacks are only slightly intercalated. However the surface modification of MMT clays improves the interfacial interaction with epoxy resins and the nanocomposites obtained through sonication exhibit enhanced mech. properties compared to the nanocomposites prepd. from pristine Na-MMT. (c) 2010 American Institute of Physics

Electrospinning and Melt blowing are the most commonly used processes to produce microfibers from extruded polymer solution or melt. The present study deals with the dynamic modeling of the instabilities and related processes during producing microfibers. A bead‐viscoelastic element fiber model is employed in modeling three‐dimensional paths of the fiber whipping in the processes of electrosping and melt blowing. The mathematical model provides a reasonable representation of the previous published predicted and experimental data.

Since the properties of semicrystalline polymers depend on the morphology, studies on effect of fillers on the composites crystallization are of great interest. In this work, a micrometric talc and a nanoclay are dispersed in a polypropylene matrix and the influence of two different fillers and temperature on the polymer crystallization behavior in quiescent conditions is assessed by means of differential scanning calorimetry (DSC) and rheological characterization through linear viscoelasticity (SAOS) [1]. The DSC tests lead to the half crystallization time, depending on overall crystallization rate (i.e. nucleation and growth) whereas by rheological measurement one can deduce also the induction time, depending only on nucleation [2].

The synthesis of metal coordination polymers is a way of affecting the processes of crosslinking of macrochains; interchain and intraionic interactions; and, thereby, preparing polymer materials with special properties [1–6]. From the standpoint of designing materials with electric and magnetic properties, it is promising to form, in a polymer matrix, chains of transition metal ions bound by exchange interaction. Conventional methods for the creation of interactions of this type in a polymer are primarily based on the presence in a macromolecule of certain units, e.g., those including the phthalocyanine and azomethine moieties, or on conformational potentialities of macrochains that contain coordination‐active groups in their branches.