To achieve low percolation thresholds in single wall carbon nanotube (SWCNT) and thermoplastic poly(butylene terephthalate) (PBT) composites, we have used an situ polycondensation reaction process. The intense dispersion process achieved first by ultrasonication followed ultrahigh speed stirring of nanotubes 1,4-butanediol the subsequent has made possible preparation nanocomposites which threshold is around 0.2 wt % SWCNT. This relatively value approaches those reported for based on...

The dynamics of a semicrystalline poly(vinylidene fluoride) (PVDF) confined within alumina templates cylindrical nanopores is studied by means dielectric spectroscopy. In this study we demonstrate how the counterbalance between spatial confinement and interfacial interactions controls at nanometer level dynamic structure polymer. A strong deviation relaxation behavior PVDF embedded observed as compared to that bulk. particular, measurements reveal, for pore sizes order 20 nm, existence...

This work presents an experimental study on the interplay between structure and dynamics during isothermal nonisothermal cold crystallization of poly(trimethylene terephthalate). Simultaneous X-ray scattering dielectric spectroscopy measurements revealed that, crystallization, crystalline lamellae tend to be homogeneously distributed along sample. A significant amount rigid amorphous phase is formed its location assigned crystal−amorphous interface. The formation less effective for...

We investigate the impact of fullerene C60 on thermal properties and glass formation polystyrene (PS) by differential scanning calorimetry (DSC) dielectric spectroscopy (DS), for concentrations up to 30% mass fraction. The miscibility dispersibility thresholds PS/C60 nanocomposites are first estimated a combination microscopy, small angle neutron scattering (SANS) wide-angle X-ray (WAXS) experiments, these were found be ≃1 mass% ≃4 C60, respectively. addition increases glass-transition...

The effects of strain-induced crystallization on the segmental dynamics vulcanized natural rubber (NR) have been studied by combining dielectric relaxation spectroscopy and wide-angle X-ray scattering. Segmental is clearly affected uniaxial stretching. For low strains, λ < 3, stretching takes place without crystallization. However, a dramatic increase strength, Δε, observed which has explained an effective dipole moment upon This effect accompanied increment fragility parameter, m, since as...

The micromechanical deformation mechanisms of a polylactic acid (PLA)/natural rubber (NR) blend (PLA/NR 90/10 wt%) and its organoclay filled bionanocomposites have been investigated by small wide angle X-ray scattering (SAXS–WAXS) under tensile conditions. addition NR to PLA matrix changed the brittle fracture ductile through debonding droplets. Otherwise, formation cavities between was hampered nanoclays since they were mainly located at polymer interface. In this case, acted as craze...

Glass formers show motional processes over an extremely broad range of timescales, covering more than ten orders magnitude, meaning that a full understanding the glass transition needs to comprise this tremendous in timescales. Here we report simultaneous dielectric and neutron spectroscopy investigations three glass-forming liquids, probing single experiment dynamics. For two van der Waals locate pressure-temperature phase diagram lines identical dynamics molecules on both second picosecond...

A large class of liquids obey density scaling characterized by an exponent, which quantifies the relative roles temperature and for dynamics. We present experimental evidence that density-scaling exponent γ is state-point dependent glass formers tetramethyl-tetraphenyl-trisiloxane (DC704) 5-polyphenyl ether (5PPE). method proposed from dynamic thermodynamic properties at equilibrium estimates value γ. The applies any state point pressure-temperature plane, both in supercooled normal liquid...

In order to understand the molecular dynamics of natural rubber, dielectric relaxation behavior its different components were investigated. These included: (1) linear polyisoprene fraction, obtained after deproteinization and transesterification rubber (TE–DPNR), (2) gel (GEL) corresponding pure chain–end cross–linked (3) deproteinized (DPNR), in which protein cross–links at ω–end have been removed, (4) (CNR) purified (through centrifugation) but still containing proteins, phospholipids sol...

We utilize inelastic incoherent neutron scattering (INS) to quantify how fullerenes affect the 'fast' molecular dynamics of a family polystyrene related macromolecules. In particular, we prepared bulk nanocomposites (hydrogenous and ring-deuterated) poly(4-methyl styrene) using rapid precipitation method where C60 relative mass fraction ranged from 0% 4%. Elastic window scan measurements, high resolution (0.9 µeV) backscattering spectrometer, are reported over wide temperature range (2–450...

Polymer nanospheres with different size distributions of poly(ethyl methacrylate) are prepared by two methods, and without the aid a surfactant. The calorimetric trace these spheres shows an increase glass transition temperature that has been evaluated means entropy model. This 3D-confinement, imposed nanospheres, leads to limiting number repeating polymer units in sphere thus reduction possible configuration states chains, which is ultimately related variations bulk value temperature. Our...

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTInfluence of Fragility on Polymer Cold CrystallizationAlejandro Sanz, Aurora Nogales, and Tiberio A. Ezquerra*View Author Information Instituto de Estructura la Materia, CSIC. Serrano 121, Madrid 28006, Spain*To whom correspondence should be addressed.Cite this: Macromolecules 2010, 43, 1, 29–32Publication Date (Web):December 10, 2009Publication History Received16 October 2009Revised18 November 2009Published...

The conduction mechanism and the molecular dynamics on paradigmatic bulk heterojunction formed by poly(3-hexylthiophene) (P3HT) phenyl-C71-butyric acid methyl ester (PC71BM) blends have been characterized dielectric spectroscopy. results show that hexyl lateral chains of polymer exhibit a high frequency local motion, similar to polyethylene-like relaxation. By spectroscopy dependence with temperature conductivity has also studied. in low region provide method estimate energy offsets system...

Abstract The composition and structure of coatings deposited with nano‐ microstructured electrodes WC‐8% Co onto Ti substrates were characterized by XRD, XPS, EPMA, SEM, SIM. Physical chemical processes taking place at the contact surface electrode substrate during electrospark deposition are considered. Under optimized conditions ( E = 0.13 J), a nanostructured provides fine‐grained exhibiting higher hardness, improved wear resistance, lower friction coefficient (compared to VK8‐based...

Abstract True model linear poly(styrene‐ b ‐dimethylsiloxane) PS‐ ‐PDMS copolymers were synthesized by using sequential addition of monomers and anionic polymerization (high‐vacuum techniques), employing the most recent experimental procedures that allow controlled each monomer to obtain blocks with molar masses. The diblock obtained analyzed different techniques, such as size‐exclusion chromatography, 1 H NMR, Fourier transform infrared spectroscopy, small angle X‐rays scattering (SAXS),...

Our aim here is to gain new insight into the nature of crystalline phase formed in supercooled glycerol near glass transition temperature and establish interrelationship between kinetics crystal growth fundamental dynamic properties. The liquid's dynamics development glycerol, a hydrogen-bonded liquid, studied by means dielectric spectroscopy. We monitored crystallization isothermal treatment at temperatures 220 240 K (Tg = 185 K). Given thermal protocol employed, we stimulated from...

Here we present an experimental study of isopropanol crystallization in real time by means a novel setup combining simultaneously structural measurements with dynamical techniques. By coupling resolved neutron diffraction and dielectric spectroscopy experiments demonstrate that breakage the hydrogen-bond network is precursor step for isopropanol.

Transformation of deuterated ethanol from supercooled liquid into a plastic crystal or rotator phase is investigated by means particular experimental setup combining simultaneously dielectric spectroscopy with neutron diffraction techniques. We demonstrate that, previous to the growth bcc lattice phase, formation precursor intermediate through liquid-liquid separation takes place. Once this formed, subsequent (plastic) crystalline nucleation and expected develop.