Highlights

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The Tencel fabrics were treated by the atmospheric pressure plasma with air.

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Samples were dyed with the C.I. Reactive Black 5 in different concentration.

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The values of dye bath exhaustion and total fixation effect increased.

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The Integ values reached the highest when the treatment time was 10 or 20 min.

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The color fastness to wet rubbing was enhanced when the dying concentration was 1%.

Abstract

The thermal degradation of eight types of high performance fibers (HPFs) was measured under nitrogen and air atmosphere. The degree of degradation, as measured by weight loss using thermogravimetric analysis (TGA), and the characteristic degradation temperatures were obtained. The kinetics of the thermal degradation has also been analyzed according to the Freeman–carroll method and the activation energies of the HPFs were estimated. The experimental results show that para-aramids (Kevlar® 29, 49, 129, and Twaron®2000) have similar thermal stability, but their thermal degradation temperatures and activation energies in air are different from those in nitrogen, which means that the thermostability of the fiber depends not only on its intrinsic structure but also on the atmosphere and temperature of testing environment. Terlon® fiber shows higher degradation temperature as a copolymer of para-aramid, and its initial degradation temperature is 476.4°C in air. It can also be found that the PBO (poly(p-phenylene benzobisoxazole)) fiber has the highest thermal degradation temperature among the samples tested, but its activation energy is not the highest in both air and nitrogen atmosphere. And the UHMW-PE (ultra high molecular weight polyethylene) fiber has the lowest thermal degradation temperature, and it begins to degrade when the temperature reaches 321.8°C under air atmosphere. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 937–944, 2006

This article provides a new approach to estimate the wettability of fibers based on the force analysis in immerging procedure. A fiber in horizontal is forced into and withdrawn from the liquid at a certain speed, and the force changes are detected simultaneously. The experimental results show that the force impulse can be found at fiber contacting with liquid and immersed into liquid, and its value depends on the wettability of the fiber. According to the force impulses of different fibers, the immerging behavior of the fibers can be obtained and categorized into four characteristics. Meanwhile, the wettability of the fibers can be evaluated with the wettability factor, w, derived from the fiber immerging curve, where w is the ratio of the force increment on fiber initially contacting with the liquid to the force increment on liquid surface closing with fiber immerging into the liquid, and with the contact angle, θ, calculated from the wettability factor (θ = π/(w+1)) supposed that the fiber is a circular cross section. The pulling-out test for a fiber has also been conducted and the results are discussed briefly in this article. The force measurement indicates that the method can be used for various fibers with short length, or lower density than that of the liquid, or poor wettability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2659–2666, 2006

The effects of the diameter, gauge length, and volume of carbon fibers on the tensile properties and their variation are discussed on the basis of the weak-link theory and Weibull distribution in a single-filament test. As far as variation is concerned, the stress of carbon fibers should be obtained by the division of the force not by the mean cross section of all the fibers but by the cross section of individual fibers because of the diameter variation. The volume effect of carbon fibers influences not only the mean of the tensile properties but also their variation. The experimental results indicate that the volume dependence in the radial direction is much bigger than that in the axial direction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3175–3182, 2006

The thermal stability of ultrahigh-molecular-weight polyethylene (UHMWPE) should be paid attention in its applications, although the fiber has excellent flexible tensile properties. The measurements for two kinds of UHMWPE fibers, Dyneema SK65 (The Netherlands) and ZHF (Beijing, China), were carried out at different annealing temperatures and for different aging times. Experimental and regression analysis results showed that the aging behavior of the fibers followed an exponential attenuation with the annealing temperature and aging time. The critical temperature for the safe use of the fibers was equal to or lower than 70°C and depended on the glass-transition temperature; this was validated by tensile tests. The difference between the two fibers in the thermal properties resulted from the intrinsic supermolecular structures of the two fibers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 310–315, 2005

The birefringent distribution of poly(ethylene terephthalate) (PET) fibers has been measured by means of Senarmont's compensation in this article. The difference from the traditional method is that two new approaches (i.e., measuring the shift of either straight fringes on a fiber cylinder or arched fringes on a fiber wedge) are established to figure out the cross-birefringence at different thicknesses of the fiber. Further, the fiber radial birefringent distribution is estimated by both using a series of theoretical models and their algorithms and by measuring with the fiber-wedge method combined with deferential calculation. There exists high coincidence between theoretical and measured values and the PET fiber is a skin-core structure of macromolecular orientation. Meanwhile, the experimental results show that (1) the double-angle measurement set a fiber at both the 0° and the 90° positions is necessary for high accuracy; (2) the setting of each optical element and the fiber is vitally important to obtain the exactly compensated values; and (3) the bulk birefringence is correlated with the measured initial modulus of the PET fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 598–608, 2004