Poly fiber diagram

To clarify the tacticity problem, trans-l,4-hexadiene and 5-methyl-l,4-hexadiene polymers were examined by X-ray diffraction. Fiber diagrams were obtained from samples stretched to four times their original lengths. Eight reflections from the poly(trans-1,4-hexadiene) fiber pattern may be interpreted on the0basis of a pseudo-orthorhombic unit cell with a = 20.81 + 0.05 A b =... 

Figure 6. X-ray fiber diagram of poly(5-methyl-1,4-hexadiene) prepared with a Etj,AlCl/S-TiCl, catalyst at 0°C in pentane solvent. Compression molded sample cold drawn to four times its original length.

Figure 4. X-ray fiber diagrams of ethoxy-substituted, hexamethylene-spacer poly(ester). a, Before magnetic alignment b, after magnetic alignment and c, fiber. Sample-to-film distance, 4.7 cm.

Fig. 20.—X-ray Fiber Diagram from Poly-(l— 4)-/3-D-xylopyranose. (Fiber axis is vertical this corresponds to the hydrated crystal-form. )...

Figure 3.3 Fiber diagram obtained with a highly stretched poly (a, a -dimethylpropiolac-tone). (Courtesy of E. S. Clark.)...

Figure 5-6. Fiber diagram of a drawn film of it-poly(propylene) (R. J. Samuels).

Hgurc 4.14 (a) A typical phase diagram for a poly (p-phenylene terephthala-mide)-sulfuric acid system, a solution that is used to make Kevlar fiber (after Kikuchi, 1982). (b) Viscosity versus polymer concentration in PPTA/HjSO solution. Note the sharp drop in viscosity at about 20% which corresponds to a transition between isotropic and nematic liquid crystal phase. 

Full circles denote observed reflections, open circles absent reflections that would be observed if all orientations about the fiber axis were present (fiber type orientation). While the 100 reflection is observed in poly(i.-methionine), it is weaker than would be expected if the orientation were fiber type, and it appears that the (100) planes develop preferentially parallel to the surface and (110) planes perpendicular (5). The diagram for poly(y-methyl-ia-glutamate) is constructed from earlier data (12) with a very similar unit cell a = 11.8 A, c = 27.0 A, compared with a = 11.46 A, c = 26.8 A for poly(i.-methionine). The cell size and the positions of the reflections are consistent with the presence of an a-helix containing 18 residues in five turns. The hatched areas denote the position of layer line streaks. The meridional 00,18 reflections at about 1.5 A are not shown. 

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