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Cold Drawing (cold + drawing)
Selected AbstractsRheology behavior of high-density polyethylene/diluent blends and fabrication of hollow-fiber membranes via thermally induced phase separationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2010Jianli Wang Abstract The phase-separation behavior of high-density polyethylene (HDPE)/diluent blends was monitored with a torque variation method (TVM). The torque variation of the molten blends was recorded with a rheometer. It was verified that TVM is an efficient way to detect the thermal phase behavior of a polymer,diluent system. Subsequently, polyethylene hollow-fiber membranes were fabricated from HDPE/dodecanol/soybean oil blends via thermally induced phase separation. Hollow-fiber membranes with a dense outer surface of spherulites were observed. Furthermore, the effects of the spinning temperature, air-gap distance, cold drawing, and HDPE content on the morphology and gas permeability of the resultant membranes were examined. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Relationship between the crystalline structure and mechanical behavior in isotropic and oriented polyamide 12JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Nadya Dencheva Abstract This study reports on the relationship between the crystalline structure and mechanical behavior of differently processed and annealed polyamide 12 (PA12) samples. Two sets of samples were obtained: isotropic PA12 films prepared by hot pressing and oriented cables prepared by consecutive extrusion and cold drawing. These samples were isothermally annealed in the range of 80,160°C and then subjected to tensile tests at room temperature. A combination of solid-state 13C-NMR and synchrotron wide- and small-angle X-ray scattering was used to obtain reliable structural data from these samples before and after the tensile tests. These structural data were related to the mechanical properties of the respective PA12 samples. Deformation models explaining all the experimental results were suggested for the different PA12 samples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Effect of flow history on poly(vinylidine fluoride) crystalline phase transformationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Hadi Sobhani Abstract This study was devoted to the effect of extensional flow during film extrusion on the formation of the ,-crystalline phase and on the piezoelectric properties of the extruded poly(vinylidine fluoride) (PVDF) films after cold drawing. The PVDF films were extruded at different draw ratios with two different dies, a conventional slit die and a two-channel die, of which the latter was capable of applying high extensional flow to the PVDF melt. The PVDF films prepared with the two-channel die were drawn at different temperatures, strain rates, and strains. The optimum stretching conditions for the achievement of the maximum ,-phase content were determined as follows: temperature = 90°C, strain = 500%, and strain rate = 0.083 s,1. The samples prepared from the dies were then drawn under optimum stretching conditions, and their ,-phase content and piezoelectric strain coefficient (d33) values were compared at equal draw ratios. Measured by the Fourier transform infrared technique, a maximum of 82% ,-phase content was obtained for the samples prepared with the two-channel die, which was 7% higher than that of the samples prepared by the slit die. The d33 value of the two-channel die was 35 pC/N, which was also 5 pC/N higher than that of the samples prepared with the slit die. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Yielding behaviour of thermoplastic/elastomer blends cured by gamma irradiationPOLYMER INTERNATIONAL, Issue 3 2001A Shaltout Abstract Mechanical blends of thermoplastic medium density polyethylene (MDPE) and elastomeric ethylene propylene diene monomer (EPDM) have been prepared with a fixed composition of 60/40,wt%. They have been used either in their gum form or loaded with two different reinforcing fillers, high abrasion furnace (HAF) carbon black or precipitated SiO2 (Hi Sil) of concentration 25,100,phr (parts per hundred parts of resin) with respect to the blend. Curing was achieved by gamma irradiation. Yielding properties (yield stress, yield strain and cold drawing) have been followed as a function of irradiation dose for different blend compositions. Yield stress values increased with irradiation dose and with the content of the reinforcing filler, but yield strain and cold drawing values decreased with irradiation dose and also with the filler content. The data obtained reveal that Hi Sil is more effective as a reinforcing filler, and the prepared blends are suitable for load-bearing applications. © 2001 Society of Chemical Industry [source] | ||||||||||