Properties of biaxially oriented

Table 11.2 Typical properties of biaxially oriented polystyrene sheet (OPS)...

Table III. Properties of Biaxially Oriented PBZT Film...

Table 3.8. Tensile Properties of Biaxially Oriented Sheeting ...

Table 9.33 Tensile properties of biaxially oriented PTFE sheeting unreinforced and reinforced...

PROPERTIES OF BIAXIALLY ORIENTED PP HLMS Optical properties... 

A major topic of interest relating to film structure is the effect of crystallinity on the deformation mechanism. The optical properties of biaxially oriented films were studied in 1957 by Stein [109] who determined the full set ofbirefrin-gences, by measuring the optical retardation as a function of the tilt of a PS film. Samuels [110] used complementary techniques of x-ray scattering, TEM of surface replicas and birefringence measurement in a study of the microstructure... 

The orientation and properties of polyethylene films produeed by the blown-film technique have been studied by many researehes in literature [2-6]. The correlation between orientation and morphology of oriented polyethylene (mostly blown film) has been studied thoroughly as well [7-10]. Mechanieal and viseoelastic properties of biaxially oriented films produeed by double bubble method were also investigated [11-13]. 

Kim, J. C Cakmak, M. and Zhou, X Effect of composition on crystalline orientation and optical properties of biaxially stretched PEN/PEI films, in Proceedings of the 55th SPE ANTEC 97 Conference, May 5-8, 1997, Toronto, ON, Canada, Society of Plastics Engineers, Brookfield, CT, 1997, Vol. 2, pp. 1588-1592. 

Fig. 13.39 Mechanical properties of biaxially (helicoidally) oriented PS. [Reprinted by permission from K. J. Cleereman, Injection Molding of Shapes of Rotational Symmetry with Multiaxial Orientation, Soc. Plast. Eng. J., 23, 43 (1967).]...

Commerically available samples of biaxially oriented polystyrene and SMA copolymer sheet material, having a thickness of 0.0381cm, were used in this investigation. It is generally recognized that crystallization under stress can enhance the tensile properties of a semi-crystalline polymer through a special arrangement of the crystalline portion ( 23). Therefore, the physical properties of the styrene-maleic anhydride copolymers chosen were compared to those of polystyrene produced in the same manner and are shown in Table I (24). 

Kim, J. C., Cakmak, M. and Zhou, X., Effect of composition on orientation, optical and mechanical properties of biaxially drawn PEN and PEN/PEI blend films. Polymer, 39, 4225-4234 (1998). 

The blown-film technique has several advantages the relative ease of changing film width and caliber by controlling the volume of air in the bubble and the speed of the screw the elimination of the end effects (e.g., edge bead trim and nonuniform temperature that result from flat film extrusion) and the capability of biaxial orientation (i.e., orientation both in the hoop direction and in the machine direction), which results in nearly equal physical properties in both directions, thereby giving a film of maximum toughness. 

The principal uses of biaxially oriented PET film are in capacitors, in slot liners for motors, and for magnetic tape. Although a polar polymer, its electrical insulation properties at room temperature are good (even at high frequencies) because at room temperature, which is well below Tg (69°C), dipole orientation is severely restricted. 

Oriented Film Film that has been oriented either monoaxially (in one direction), the direction of tear, or biaxially (in two directions), to achieve strength and stiffness. Monoaxially oriented tape exhibits stronger MD (machine direction) tensile properties than biaxially oriented tape. Materials that have been oriented bear an O before the acronym (e.g., OPS, oriented polystyrene). 

Properties of metallocene-based PP are compared with properties of conventional PP in Table 2. Metallocene-PP exhibits higher stiffness and improved optical properties. Improved orientation of metallocene-based PP offers opportunities for production of biaxially oriented PP film (Table 3) and PP fibers (Table 4). In fact, metallocene-PP can be spun at... 

Samuels, R.J. (1970) Qualitative structural characterization of the mechanical properties of isotactic polypropylene. J. Macromol. Sci. Phys., B4, 701-59. Uejo, H. and Hoshino, S. (1970) Structure of biaxially oriented polypropylene film. J. Appl. Polymer Sci., 14, 317-23. 

The mechanical properties of biaxially drawn PHB are intermediate between those of poly(ethylene terephthalate) and polypropylene as shown in Table 11. The biopolymer films are mechanically strong and tough, and they are transparent with good clarity. Moreover, their gas barrier properties, particularly to oxygen, are excellent and much superior to those of uncoated polyolefin films. In fact PHB and its copolymers would appear to have a promising future as packaging materials in both oriented and unoriented form. 

K. J. Presswood, in Oriented PVC Bottles Process Description and Influence of Biaxial Orientation on Selected Properties, 39th Annual Technical Conference, May 1981, Society of Plastics Engineers, Inc., Brookfield Center, Conn., pp. 718-721. 

The theoretical descriptions of biaxial orientation and the relationships to physical properties are not as well developed as those of uniaxial orientation. In amorphous polymers, birefringence can measure total molecular orientation and can be used to predict properties. For semicrystalline polymers, a more... 

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