Rates of crystallization of copolyamides. II. Random copolymers of nylons 66 and 6

Abstract

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

Polyamides – Still Strong After Seventy Years

“…This block copolymer shows a monotonic rise in T m from the lower melting to the higher melting polymer; as stated, block copolymers will not be discussed. Harvey and Hybart [169] further explored this copolymer system in its randomized state, measuring melting points, crystallization rates, and densities for 12 different proportions, from 100% PA 66 to 100% PA 6. Crystallization was found to require lower temperatures (i.e., to be more difficult) for the mixtures.…”

Synthesis of copolyamides containing octadecanedioic acid: An investigation of nylon 6/6,18 in various ratios

“…Widely used copolymers are made up of nylon 6 units with nylon 6,6 monomers in various ratios. Comonomers may be entirely aliphatic [7][8][9][10][11][12][13] or may incorporate some aromatic content. 14,15 However, even in copolymer samples with reduced crystallinity, virtually all the amide linkages are fully hydrogenbonded, leading to a material with good mechanical properties.…”

Polyamides

“…In a PA 66/6 copolyamide, for example, the melting point minimum is about 180 C at 40 wt% of caprolactam units. PA 66/6 copolymers with about 40-65 wt% caprolactam units become soluble in hot methanol whereas the homopolymers PA 6 and PA 66 are insoluble in this solvent [19,193,194]. Terpolymers such as PA 66/6/610 are designed to further enhance solubility for use as binders [19,195].…”

“…One commercial example is a blend of nylon and poly (2,6-dimethyl-p-phenylene oxide). Allusion has been made to a blend with poly(phenylene sulfide) as the major ingredient [194]. Another composition presumably involves mostly ABS and some nylon [195].…”

“…The literature on blends is voluminous. Brief reviews of commercial blends including some commentary on their processing are given in [194][195][196]. A recent text focuses specifically on commercial blends and alloys [197].…”