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The crystalline phase of gelled ultrahigh molecular weight polyethylene derived from reactor powders with different synthetic prehistories is studied by means of low frequency Raman spectroscopy and small angle X ray scattering. The results obtained suggest that the gels contain folded crystallites 3-6 nm in size that, in some samples, form stacks of two or more units bound by common straightened segments of mac romolecules (double folds). The gels are used to prepare highly oriented polyfilament fibers, and the strengths and Young moduli of the fibers are estimated. The gels containing stacks of crystallites demonstrate better ability to form high strength fibers during hot drawing than the gels containing individual crystallites. The effect of the strength of junctions in the polymer spatial network of the gels on the attainment of optimum mechanical properties of the drawn fibers is discussed.

Linear [B,10]-polyamines [(CH2)BN(CH3)(CH2)10N(CH3)] were prepared (B = 3 or 6). Protonated by stoichiometric amounts of n-alkylsulfonic acids, they form demethyl-ionene sulfonate complexes, which proved thermally stable up to 220 °C. Salt free complexes were investigated by polarized microscopy, thermogravimetry, and X-ray diffraction. Except the heptyl sulfonate, which crystallized, all complexes bearing longer alkyl chains formed mesogenic phases. Being isotropic in dry state, they became optically anisotropic when exposed to humidity due to a lyotropic transition (mediated by the gas phase) to a hexagonal phase, mostly. A cubic phase containing less water was also observed. Anisotropic complexes again were converted to an isotropic state upon heating under controlled humidity. The clearing temperatures distinctly depend on humidity and rise with increasing length of the alkyl sulfonate. This may allow the use of the complexes as humidity sensors. Oriented liquid crystalline samples are formed upon fast cooling in flat capillaries.