Polarized far-infrared spectra of aliphatic polyesters [–(CH2)z–CO–O–O]n with z = 1, 2, and 5 (z = 4, nonpolarized) and α-polyamide (nylon 6 and its N-deuteroderivative) have been measured in the region up to 80 cm−1. All these polymers have essentially planar zigzag conformations. The normal vibrations of these polymers were calculated for the far-infrared regions by using the Urey–Bradley force field with some modifications. For the series of polyesters, several far-infrared bands were found to appear systematically at nearly the same positions with similar intensities. The similarities between these series of bands of the polyesters and those of polyamides were interpreted from the point of view of the normal modes of vibrations.

The relationships, between chemical structures of various aromatic polyimides and their thermal expansion coefficients, were investigated and the properties of low thermal expansion polyimides were elucidated. Such low values were observed for polyimides obtained from pyromellitic dianhydride or 3,3'.4,4'-biphenyltetracarboxylic dianhydride and aromatic diamines. which included only benzene or pyridine rings fused at para-positions without a flexible linkage. It was proposed that these low thermal expansion coefficients were related to the lineerity of their polymer molecular skeletons. In particular, PIQ-Ll 00 (Hitachi Chemical Co. Ltd) i s one such low thermal expansion polyimide and, it has excellent mechanical properties, thermal stability, and low absorbed moisture content.

the sequence distribution, ~8% in the polymer composition, and ~50 % in the monomer feed are shown for a VC1-BMA copolymer. Errors of ~18% in the sequence distribution, ~4% in the polymer composition, and ~1 % in the monomer feed are shown for a BD-MMA copolymer. Large errors are not expected in any of the variables, but erroneous reactivity ratios may also arise from a cumulation of smaller errors.The effect on predicted reactivity ratios of an ~2% error in all variables is also shown in Table V for both the VC1-BMA and BD-MMA copolymers. It is doubtful that errors of this degree would occur in all variables simultaneously, but the error range found indicates the experimental care that must be taken in using this approach. Accurate measurement of variables will, however, give favorable reactivity ratio comparisons as shown in Table II. ConclusionsReactivity ratios may be predicted in copolymer systems susceptible to sequence distribution measurements by accurately knowing the monomer feed, the copolymer composition, and the copolymer sequence distribution. Reactivity ratios can be obtained with a minimum amount of polymer synthesis and may be used to predict desired copolymer compositions. The singlecopolymer reactivity ratio technique could possibly be used to illustrate shifts in reactivity ratios attributed to penultimate effects or polymerization mixture polarity changes.The single-copolymer reactivity ratio method may prove to be valuable in specific systems where accurate sequence distribution data can be obtained and the use of conventional methods for finding reactivity ratios is not practical.

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Poly(4-vinylphenol) sensitized by an aromatic monoazide compound (4-azidochalcone), called MRL (Micro Resist for Longer wavelengths), has been prepared and evaluated as a negative UV resist. The resist is sensitive to radiation in the 300 to 400 nm region. The sensitivity of MRL is comparable to that of a positive quinonediazide photoresist under exposure to unfiltered light from a high pressure Hg lamp. An aqueous base developer removes the unexposed areas of MRL with no evidence of swelling of the exposed areas, indicating its high resolution capability. The main products in the exposure of MRL films are found to be primary and secondary amines. It is concluded that the formation of secondary amines attached to the polymer chain is responsible for the insolubilization of the exposed MRL in the base developer.