In situ Raman spectroscopy is applied to high-density polyethylene elucidate the microscopic deformation mechanism during uniaxial stretching. The peak shifts of C-C stretching modes amorphous chains show remarkable red in elastic region, where as shift vibration along crystalline chain begins after first yield point, suggesting that stress concentrated on before point.

Recently we developed a new microwave spectroscopy technique in the frequency range up to 40 GHz, and measured static dielectric constant relaxation time for supercritical water. In present work report properties of heavy water at temperatures pressures 770 K 59 MPa, respectively. The D2O as well H2O are described by Uematsu–Franck formula when number density instead mass is used input parameter. decreases rapidly with increasing temperature liquid jumps large value liquid–gas transition....

A new physical method was proposed to control the liquid properties of room temperature ionic liquids (RT-ILs) in combination with nanoporous materials; melting point ILs confined nanopores remarkably decreases proportion inverse pore size.

The influences of the polydispersity index (Mw/Mn) on morphology and deformation behavior high-density polyethylene solids under uniaxial stretching were investigated using in situ Raman spectroscopy. An increase Mw/Mn led to a larger fraction tie molecules connecting several lamellar crystals, whereas no obvious influence crystalline structures was observed. Although stress–strain curves essentially remained unchanged up neck propagation region irrespective Mw/Mn, strain-hardening modulus...

In situ Raman spectroscopy has been used to reveal the molecular behavior of isotactic polypropylene during melting and crystallization. The 400 cm–1 band assigned C–C–C bending shows a blue-shift heating, suggesting an increase in conformational disorder, whereas 1330 CH2 twisting red-shift owing interchain distance. We suggest that expansion proceeds even melt state, while chain conformation becomes sufficiently disordered at point. During cooling process, peak shifts given temperatures...

The molecular orientation behavior of isotactic polypropylene (iPP) is investigated by using in situ Raman spectroscopy under tensile tests.A versatile method the tilt-angle correction for parameters newly developed, where highly oriented specimens assumed to be entropically favorable.The real-time changes and distribution functions are determined chain axis iPP during uniaxial stretching.The remains random elastic region, increases after first yield point.In yielding a broad toward an...

Photodetachment of electrons from iodide ions produced diiodide anion radicals in ionic liquids containing ammonium, pyrrolidinium, and piperidinium cations. The rates reaction between molecular solvents such as H2O, methanol, ethanol could be estimated by the Debye-Smoluchowski equation, which accounts for electrostatic interactions using dielectric constants solvents. In contrast, were close to diffusion-limited neutral molecules, suggesting that repulsion is weakened Coulombic shielding liquids.

Electrochemical carboxylation is conducted in ionic liquids compressed with carbon dioxide. It found that the current efficiency increases temperature and pressure. The diffusion coefficient of substrate, which obtained from electrochemical measurements, also remarkably increase mainly explained by improvement mass transfer, promotion liquid achieved pressurizing dioxide moderately.

We found that the dynamic mechanical spectra of linear high-density polyethylene (HDPE) can be controlled by swelling using liquid paraffin (LP) at 100 and 110 °C. The relaxation strength α observed above 50 °C decreased with an increase in time. Two novel peaks appeared between γ relaxations, denoted as β1 β2 on lower temperature side, respectively. These are absent pristine HDPE associated immersion LP molecules amorphous phase. approximately −50 was almost independent frequency; it is...

The influence of the weight-average molecular weight (Mw) on structure–properties relationship was investigated by preparing high-density polyethylenes (HDPEs) various Mw but constant polydispersity index (Mw/Mn) values. thickness lamellar crystalline layer increased with increasing Mw, whereas amorphous characteristics, such as and tie-molecule fraction, remained unchanged. microscopic deformation these HDPEs in situ Raman spectroscopy. orientation parameter ⟨P2⟩ showed a power law to an...

Dielectric relaxation of ethanol and 1-propanol have been measured in a wide fluid phase including the supercritical condition for first time. The results static permittivity ε(0) dielectric time τD are presented temperature pressure range up to 670 K 30 MPa. Kirkwood’s g-factor deduced from suggests that orientational correlation dipoles becomes prominent at densities above ∼2dc, dc being critical density. We divide into four regions discuss mechanism by extending our model previously...

In situ observation of the microscopic structural changes in high-density polyethylene during hot drawing was performed by incorporating a temperature-controlled tensile machine into Raman spectroscopy apparatus. It found that load sharing and molecular orientation elongation drastically changed at 50°C. The stress crystalline chains decreased with increasing temperature diminished around Moreover, greatly promoted above These were caused thermal activation motion within lamellar owing to...

The static permittivity ε(0) and the dielectric relaxation time τD have been obtained for methanol over a wide range of temperature pressure up to 600 K 21 MPa. decreases with increasing has little dependence in liquid state. In gaseous state, however, increases decreasing density. Since these behaviours are qualitatively same as those water, we successfully applied our model water that some appropriate modifications.

The phase behaviour of water confined in porous Vycor glass is investigated by means dielectric measurements. effective static permittivity εeff(0) the sample, which consists and pores, obtained over a wide range temperature pressure. boiling point higher than that bulk K. enthalpy vaporization for practically same as water. critical determined lying at TcH2O/V ycor = 623(± 3) K PcH2O/V 14(± 1.5) MPa; both these values are lower those

In this work, two types of solid paraffins (i.e., linear and branched) were added to high-density polyethylene (HDPE) investigate their effects on the dynamic viscoelasticity tensile properties HDPE. The branched exhibited high low crystallizability, respectively. spherulitic structure crystalline lattice HDPE are almost independent addition these paraffins. paraffin in blends a melting point at 70 °C HDPE, whereas showed no blend. Furthermore, mechanical spectra HDPE/paraffin novel...