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Ultra-high molecular weight isotactic poly(1-butene) (UHMW-PB1) melt-grown crystal (MGC) films were drawn using the PIN drawing technique. Although the UHMW-PB1 MGC films had poor ductility in the crystalline state, they were ultradrawable in the molten state above the static melting temperature (T m ). The drawability of the MGC films was strongly influenced by the draw temperature, the sample...
The uniaxial drawing of UHMW-PAN fibers spun from a dilute solution into methanol coagulation baths at different temperatures and the resultant structure and tensile properties of the drawn products were studied. Although the initial morphology of the fibers and the deformation mode in a lower draw ratio (DR t ) range were significantly dependent on the temperatures of the coagulation bath,...
A film of poly(l-lactic acid) (PLLA) consisting of highly oriented α crystals was uniaxially drawn by tensile force. The effects of the draw ratio (DR), draw temperature (T d ), and draw stress on the crystal/crystal transformation from the α- to the β-form crystals were studied. At the initial stage of drawing, the highly oriented α crystals of the starting film transformed into a broader...
Amorphous films of poly(ethylene terephthalate)/poly(ethylene-2,6-naphthalate) (PET/PEN) blends with different blend ratios were uniaxially drawn by solid-state coextrusion and the structure development during solid state deformation was studied. As-prepared blends showed two Tgs. The lower Tg was ∼72°C, independent of the blend ratio. In contrast, the higher Tg increased with increasing PEN content...
A series of ultrahigh-molecular-weight polyethylenes with comparable viscosity-average molecular weights of around 2×10 6 has been prepared by using a high-activity Ziegler catalyst at different temperatures (T poly ) in the range 20–90°C, in hexane. The ductility and morphology of the nascent reactor powders have been studied. With decreasing T poly , the drawability of the...
Solid-state coextrusion draw was carried out for films of aggregates of solution- and melt-grown crystals of nylon-6 and α- and γ-forms. Under ordinal crystallization conditions, the crystal form was primarily a monoclinic α-form. Thus, α-crystals were converted to the γ-form by iodine treatment, followed by treatment with aqueous solution of sodium thiosulfate. The maximum extrusion draw ratio...
The tensile properties and uniaxial drawing of highly syndiotactic polypropylene (s-PP) have been studied. The results were compared to those of isotactic polypropylene (i-PP) having a comparable molecular weight, molecular-weight distribution and stereoregularity. S-PP and i-PP of different initial morphologies, prepared by crystallization from the melt and solution, were drawn by solid-state coextrusion...
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