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synopsisRates of crystallization of copolyamides of riylons 66 and 6 have been measured by a photometric technique using a hot-stage microscope. The copolymers all show some crystallinity, but the temperatures of crystallization are reduced as more comonomer is introduced. A close correlation between melting and crystallization behavior is observed. The copolymerized component is acting as a diliient rather than entering the homopolymer crystal. 2133

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The results of laboratory semi‐bulk and bulk trial work on the dyeing of nylon 6.6, with anionic dyes in the presence of n‐butanol, in an aqueous dyebath are described. The method gives improvements in coverage of barre which cannot be achieved in other ways, without detectable adverse effects on the physical properties of the nylon 6.6 or the colour and fastness properties of the dyes. Results of work by a similar, solvent‐assisted dyeing method for polyester fibre are given. Improvements in migration and speed of fixation of dye in the presence of n‐butanol are noted, but these are similar in magnitude to the improvements obtainable with conventional carriers for polyester dyeing at much lower concentrations. The method is likely to be commercially viable only if a substantial proportion of the butanol added to the dyebath can be recovered for re‐use. This should theoretically be possible, but experimental confirmation of the process has not yet been obtained.

With the advent of the filament-wound glass fiber — resin pressure vessel, a material unlike any encountered previously was brought into the field. Metals and plastics having anisotropic structures have been commonplace, to be sure, but a two-phase system consisting of fibers of high tensile strnegth embedded in a matrix of softer plastic was a new situation. The old testing problems, such as physical property testing, thickness gaging, defect detection, and so on, were still present, but a host of new structural parameters requiring nondestructive examination were found to exist. In many instances the “tried-and-proven” non destructive test methods were ineffective for extracting needed structural information. A fortuitous exception to this was radiography, without which the entire glass fiber rocket motor case program would have been retarded.