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Stress-strain data have been obtained for poly(vinyl chloride) from drawing experiments in three stretching modes: uniaxial, planar and equibiaxial extension. The experiments were conducted isothermally at 84°C, which is in the glass transition region, and at 90°C, above T g . The stress-strain behaviour is qualitatively different at the two temperatures. At the lower temperature, there...
Highly oriented films of poly(dimethylsilylene) on smooth substrates such as glass and quartz plates were prepared by the friction deposition technique. The structure of the oriented film was characterized by polarized optical microscopy, transmission electron microscopy and polarized ultraviolet absorption spectroscopy. The polymer backbone in the film was parallel to the sliding direction. The...
A quantitative treatment of the specular reflection spectra obtained from the surface of uniaxially drawn poly(ethylene terephthalate) samples has been performed. A procedure for correcting for the effect of surface irregularities is presented, and an overall orientation function based on the orientation and content of trans conformers is calculated. The results are correlated with mechanical modulus...
The deformation behaviour of amorphous poly(aryl ether ether ketone) films above the glass transition temperature is studied by analysing the amorphous orientation function and shrinkage stress variationsversus draw ratio in the framework of the two component model of Brown and Windle which considers separate orientational and extensional contributions to the overall strain. This analysis is in line...
Drawing of poly(ethylene terephthalate) (PET) films was performed from the amorphous state at different drawing rates and at 80°C. Crystallinity of the films was determined by thermal analysis and orientation of the different phases was determined by birefringence, Fourier transform infra-red (FTi.r.) specular reflection and wide angle X-ray diffraction. The mechanical properties of the oriented...
The influences of substrate surfaces on the formation behaviour of banded texture and its thermal stabilities have been studied for an aromatic X-shaped main-chain liquid crystalline polyester. The oriented polymer films prepared by shear on a glass substrate were found to exhibit a strong bounding effect, which was very effective in stabilizing or keeping the structural orders of oriented polymer...
Molecular orientation and mechanical properties of miscible poly(styrene)/poly(vinyl methyl ether) (PS/PVME) blends were compared with those of heterogeneous PS/PVME blends prepared above their temperature of phase separation. The second moment of the orientation function and the Young's modulus of the heterogeneous systems were found to be higher than those of the corresponding miscible compositions...
A range of aromatic polyesters containing terphenyl units in the main chain and alkyl side chains have been investigated with respect to their structure and orientation development. As-cast films showed a layered structure: layers of the main chains were preferentially organized parallel to the film surface. Upon drawing of these films, the structure changed to a fibre-symmetric one, as was proven...
A method for the reproducible production of isotropic free standing camphorsulfonic acid doped polyaniline with a conductivity of (300 ± 30) S cm -1 is described. The paper then goes on to describe a method of stretch orienting such films to enhance the conductivity parallel to the draw direction to (890 ± 30) S cm -1 . This improvement is attributed to orientation of both...
Two-dimensional magic angle spinning (2D-MAS) 13 C n.m.r. spectroscopy and FTi.r. microscopy have been used to measure the orientation in uniaxially drawn film as a function of draw ratio. Results obtained agree well with those obtained by optical birefringence measurements. FTi.r. microscopy is a powerful method for mapping the orientation across the film thickness with quick data...
Films of polyaniline doped with (±)-camphor sulfonic acid, cast from m-cresol, exhibit considerable metallic properties. Such films are partially crystalline, but appear macroscopically disordered when probed by X-rays. Changing the X-ray geometry to probe molecular trajectories within the thickness of such films reveals considerable anisotropy; the molecules statistically adopt a chain direction...
Several liquid-crystalline elastomers (LCEs) have been prepared by crosslinking side-chain type liquid-crystalline polymers (precursors) in which mesogens are dangling from flexible main chains through spacers. Thermal properties and phase behaviour of the precursors and LCEs have been investigated by means of differential scanning calorimetry (d.s.c.) and polarizing microscopy. The glass transition...
Samples of approximately uniform degree of orientation based on poly(hydroxybenzoic acid (73 mol%)-co-hydroxynaphthoic acid (27 mol%)), known as Vectra A950, were obtained by sectioning injection-moulded specimens. The degree of chain orientation was assessed by X-ray scattering and infrared spectroscopy. A comparison of the data obtained by the two methods enabled the angles between the chain axis...
An experimental study of the development of molecular orientation in the amorphous phase during the transverse drawing of one-way drawn poly(ethylene terephthalate) films has been carried out. Both the behaviours of phenyl ring normals or chain axes and of fluorescent rigid probes have been considered. The influence of the size of the crystallites in the one-way drawn films has been studied. It...
Films of isotactic polypropylene (iPP) and a blend of iPP and hydrogenated oligocyclopentadiene (HOCP) oriented by one-way (uniaxial) and two-way (sequential biaxial) drawing were studied. The mechanical and thermal properties of the oriented iPP and iPP/HOCP blends as well as orientation behaviour were investigated by means of mechanical tests, d.s.c. and small- and wide-angle X-ray scattering including...
By the Raman LAM experiments the length distributions of straight all-trans sequences were obtained for oriented polymers films of varied draw ratios λ. A shape of distribution function depended on λ and draw temperature as well: the higher λ the more long trans-stems could be observed in the oriented material. The experimental facts were matched to the results of the computer structure simulation...
A systematic series of well-defined aromatic polyesters and a poly-para-phenylene with aliphatic side chains were investigated. Films were mechanically characterized by DMTA. The chain modulus was estimated using an extrapolation method based on the aggregate model. The extrapolated values are comparable with theoretically calculated moduli, but display a fairly large uncertainty. Comparison of...
Ultra-high-molecular-weight polyethylene (UHMWPE) samples of molecular weight 6 million were compressed using a channel die and characterized by wide-angle and small-angle X-ray scattering. The results were compared to previous studies performed on high-density polyethylene (HDPE) under the same compression conditions. Most deformation mechanisms exhibited by UHMWPE were also observed in HDPE. ...
The orientation induced by stretching uniaxially in the solid state two semi-crystalline miscible blends of poly( -caprolactone) (PCL) with poly(vinyl chloride) (PVC) and poly(styrene-co-acrylonitrile) (SAN) was investigated by infrared dichroism. In both cases, the deformation of the solution-cast films, having a high PCL crystallinity degree of about 50% and containing up to about 40wt% of PVC...
PET/0.6 PHB melt, where PET is poly(ethylene terephthalate), PHB is p-hydroxybenzoic acid and 0.6 is the mole fraction of the second (liquid crystal, LC) component in the copolymer, was subjected to constant magnetic fields at several temperatures in the range 240-315 o C, cooled to 25 o C, and then studied by x-ray diffractometry, electron diffractometry, scanning electron microscopy...
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