Morphology and Mechanical Property of Nylon 6 Fibers in the Flags Exposed on the Route between Syowa Station and Dome Fuji in the Antarctic

et al. 2007

Macro Materials & Eng

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To improve the poor mechanical properties of uniaxially ultra‐drawn films along the transverse direction, lamination of two ultrahigh molecular weight polyethylene/ethylene dimethylaminoethyl methacrylate copolymer blend films was carried out in the rectangular elongation direction by a microwave heating method. The characteristics of the successful laminated films were analyzed theoretically and experimentally. The original orientation of the crystallites for the blend films was maintained perfectly after lamination, and the preferential directions intersected each other. The Young's modulus increased symmetrically with respect to the 45 ° direction. This is the first report concerning a drastic improvement of the Young's modulus in the transverse direction for films ultra‐drawn along one direction.magnified image

Section: Microwave Heatingmentioning

confidence: 99%

Morphology and High Modulus of Laminated Ultra‐Drawn Polyethylene Films with Biaxial Orientation Prepared by Microwave Heating

Azuma

Chen

et al. 2007

Macro Materials & Eng

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Characterization of PVA and Chitosan/PVA Blends Prepared from Aqueous Solutions of Various Na₂SO₄ Concentrations

Drambei

Macromolecular Symposia

Bin

et al. 2006

Uniplaner orientation of a particular crystal plane along the surface of a film was investigated for poly (vinyl alcohol) (PVA) film prepared by a coagulation bath with concentrated aqueous solution containing 100 ∼ 300g of Na2SO4 against 1 ℓ of water. The orientation distribution functions of the three crystallographic principal axes of the dried films were obtained by the X‐ray diffraction technique. The same treatment was carried out for the films prepared by stretching biaxially of the fresh gel and then by drying the resultant fresh gel. The very high preferential orientation of the crystal chain axes and amorphous chain segments could be realized by the biaxially elongation. Accordingly, the techniques were applied to the biaxially stretching of chitosan and PVA blend films with high Young's modulus. The planer orientation of the chain axes of chitosan and PVA crystallites could be confirmed. The morphology of the film surface was estimated by measurements of contact angle and electron spectroscopy for chemical analysis. The results suggested that the admixture of chitosan decreases wet ability of the specimen and this tendency was slightly enhanced by the biaxially elongation.

Structure and Mechanical Properties of Chitosan/Poly(Vinyl Alcohol) Blend Films

Macromolecular Symposia

Bin

Bando

et al. 2007

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The origins of the thermal and mechanical properties of chitosan and poly(vinyl alcohol) (PVA) with inter-and intra-hydrogen bonds were investigated systematically by using X-ray, DSC, positron annihilation and viscoelastic measurements. Based on their individual properties, the characteristics of the blend films were estimated in relation to their morphology and mechanical properties as a function of chitosan content. The characteristics of the blend films were also analyzed in terms of the deviation from a simple additive rule of chitosan and PVA content. These results suggested that the miscibility of chitosan and PVA could be ensured by entanglement of the amorphous chain segments of chitosan and PVA. Further detailed analysis revealed that the chitosan content on the film surface is higher than that of the admixture content of chitosan after elongation, although the chitosan and PVA chains were crystallized independently. The elongation could be achieved for the blend films whose PVA content was higher than 50% and the drawn blend films were transparent. Thus, it may be expected that sufficiently entangled meshes formed between chitosan and PVA amorphous chains within the film, the PVA content being higher than 50%, were maintained under the elongation process.