Purification of Organic Materials and Study of Polymers Therefrom.

The attainment of the high degree of purity of monomers was investigated to improve the performance of two selected polymers. Major emphasis was on the purification of adipic acid and hexamethylenediamine and the study of the effects of high monomer purity on the properties of nylon 66. The properties of a standard grade nylon prepared from high quality commercial adipic acid and distilled hexamethylenediamine were compared with a nylon obtained from monomers purified by repeated crystallization. The relative purity of the monomers, which were obtained in higher purity by the crystallization processes, was determined by chromatography and freezing point depression studies. The purity difference between the monomer grades was generally less than 0. 1 mole percent. The properties of the two polymer grades were initially compared by viscosity measurements, pyrolysis-chromatographic studies and differential thermal analysis. Films were fabricated from each polymer grade and their properties compared primarily by electrical measurements and by mechanical property measurements before and after weathering. Nylon 66 obtained from the higher purity monomers was indicated to exhibit a slightly higher molecular weight and a higher tensile strength of films after weathering than the standard grade polymer. No significant improvement of the properties of the higher purity grade nylon was evident by the various other measurements. Research was also initiated on the purification of monomers and sol- vents for polymerization to polyETHYLENE METHYLENE BIS4-PHENYLCARBAMATE. p5