Improvement of color value of bio-based polyamide 56 fibers

Abstract

This paper introduces a feasible method to improve the color value of bio-based polyamide 56 (PA56) fiber. Three types of whitening modifiers were introduced into the bio-based PA56 fibers by the in-situ polymerization method and melt blending method in order to improve the fiber color. The color values and mechanical properties of PA56 fibers were tested and analyzed and the optimum additive ratio and process conditions were discussed. The results show that the improved color value of bio-based PA56 fibers can be achieved by the melt blending method of fluorescent whitening masterbatch and reasonable spinning condition control. When the additive amount of fluorescent whitening agent is 0.3%, the index of lightness (L) increased from 84 to 90, while the yellow index (YI) reduced from 16.8 to 12.6. Moreover, PA56 fibers show high breaking strength about 4.27 cN/dtex and good yellowing resistance and durability.

Study on yellowing mechanism and inhibiting technology based on amide salts modified polyester

“…As far as we know, studies on the yellowing mechanism have focused on the blend systems, and it is generally regarded that the origin of the yellowing process is mainly due to the Schiff base reaction between acetaldehyde (a by-product of PET) and the terminal amine groups produced by the degradation of polyamides. 19,22 The structure of yellowing substances is attributed to a color-conjugated imide group, which is only applied to the amine groups with a lone pair of electrons. However, the properties of amide salts are different from primary amines.…”

“…In recent years, there have been some reports on the yellowing problem of polyester amide and its fibers. 18,19 Fan and Liu 20 effectively reduced the yellowing index of the polyester amide by optimizing the prepolymerization and polycondensation reaction conditions. However, the reaction process was cumbersome, and the minimum yellowing index was controlled at around 15.…”

Preparation and characterization of poly(ethylene terephthalate‐co‐aliphatic amide) copolymer fibers with excellent hygroscopicity and softness

“…The color value of the fibers is usually expressed by the Lab value, where the L* value directly reflects the whiteness of the fibers; In addition, the positive and negative values of a* represent the red and green values of fibers; the positive and negative values of b represent the yellow and blue values of fibers. 47,48 It directly affects the fibers applications in the textile field. The results of the Lab value of PET and copolymer fibers are shown in Figure 14.…”

Bio‐based polyamide 56 fibers by one‐step melt‐spinning: Process, structure and properties

“…The limited researches on the preparation and properties of PA56 fibers from one-step spinning process cannot provide sufficient information on the regulation of the melt-spinning process and properties of PA56 fibers. [10][11][12]21,42 Moreover, the applications of PA56 fibers are restricted due to the lack of the information on the correlation between structure and properties of PA56 fibers.…”

“…The structure formation and development of the filaments during the one‐step melting spinning process determine the properties of the resultant fibers, which might be different from those of two‐step melting spinning process. The limited researches on the preparation and properties of PA56 fibers from one‐step spinning process cannot provide sufficient information on the regulation of the melt‐spinning process and properties of PA56 fibers 10–12,21,42 . Moreover, the applications of PA56 fibers are restricted due to the lack of the information on the correlation between structure and properties of PA56 fibers.…”