Study On The Preparation And Dyeing Properties Of Polyamide-amine Modified Viscose Fiber

Viscose fibers belong to regenerated cellulose fibers,which have a wide range of sources,and viscose fibers have very good wearability and bright dyeing,and are widely used in all walks of life.PAMAM dendrimers of the second generation have very high purity and excellent spatial structure.They contain 8 primary amines and 12 amides.They have a planar open structure.The distance between groups is relatively loose,and the molecules are easily entangled with each other.Modified viscose fibers were dyed with reactive dark blue K-R by wet spinning with self-made 2-generation polyamide-amine dendrimer(PAMAM)and viscose spinning solution in different proportions.This paper mainly studies the following aspects:(1)PAMAM was synthesized by Michael addition reaction and amidation reaction with methyl acrylate alternately using ethylenediamine as initial initiating nucleus.The optimum reaction conditions were determined by comparing different time,temperature and feed ratio.The FT-IR spectra of PAMAM dendrimers were tested,and it was found that the infrared spectra of PAMAM dendrimers were consistent with the experimental theoretical structure.(2)The PAMAM dendrimer was added into the original solution of viscose spinning,and the viscose fibers were modified by wet spinning technology.The surface morphology of PAMAM modified viscose fibers was characterized by Fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).The breaking strength of PAMAM modified viscose fibers was tested by electronic single fiber strength tester.It was found that the breaking strength of PAMAM dendrimers entering viscose fibers had little effect.(3)Dyeing kinetics and thermodynamics of salt-free dyeing of PAMAM modified viscose fibers were studied by reactive dark blue K-R.By measuring the dyeing rate curve,the half-dyeing time,equilibrium dyeing percentage,specific dyeing rate constant,diffusion coefficient and adsorption isotherm were calculated.Kinetics results show that with the increase of PAMAM dendrimer content,the half-dyeing time decreases gradually,the initial dyeing rate,equilibrium dyeing percentage and specific dyeing rate constant of reactive dark blue K-R on viscose fibers increase gradually,and the salt-free dyeing of viscose fibers can be realized when PAMAM content reaches 10%.Thermodynamic results show that with the increase of PAMAM dosage,the main adsorption and dyeing mechanism of viscose fibers is changed from Freundlich physical non-localized adsorption to Langmuir chemical localized adsorption.(4)The surface morphology of PAMAM modified viscose fibers was characterized by Fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).The color fastness to washing and rubbing was determined at constant temperature.The results showed that the addition of PAMAM had no effect on the wash fastness and friction fastness of viscose fibers.PAMAM can improve the dyeing rate and percentage of viscose fibers,which is of great significance to improve the dyeing process of viscose fibers.