The influence of alkali pretreatments in lyocell resin finishing—Resin distribution and mechanical properties

Manian, Avinash P.; Rous, Mohammad Abu; Schuster, K. Christian; Bechtold, Thomas

doi:10.1002/app.23038

Cited by 15 publications

(12 citation statements)

References 16 publications

(23 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1,2 However, the strong swelling propensity of lyocell fibers in alkali solutions 3 changes substrate properties and may lead to alterations in the accessibility and reactivity of lyocell for chemicals and reagents and influence its performance in subsequent treatments. 4,5 In earlier work, 6,7 we examined the influence of alkali pretreatments on the performance of lyocell fabrics in subsequent resin finishing treatments. Fabric samples were pretreated with sodium hydroxide (NaOH; 120 g/L) or KOH (250 g/L) and resinfinished with a dimethyloldihydroxyethylene urea (DMDHEU) based product.…”

Section: Introductionmentioning

confidence: 99%

Alkali pretreatment and resin finishing of lyocell: Effect of sodium hydroxide pretreatments

Kongdee

Manian

Lenninger

et al. 2009

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

Lyocell fabric samples were pretreated with 2-8 mol/L sodium hydroxide (NaOH) and then resin-finished with dimethyloldihydroxyethylene urea, dimethyl dihydroxyethylene urea, and dimethylol urea based products. The resin-finishing treatments caused changes in the substrate properties, such as reduced accessibility, improved crease recovery, and reduced work of rupture and abrasion resistance. Differences were observed between resin-finished substrates as a function of the crosslinker type, and they were attributed to the influence of the crosslinker content and crosslink length in the substrates. The alkali pretreatments influenced the effects of resin finishing. A significant enhancement of the crosslinker penetration appeared within the substrates pretreated with 4 mol/L NaOH. Pretreatments with 6 and 8 mol/L NaOH also enhanced the crosslinker penetration, but the depth of catalyst penetration appeared to exceed that of the crosslinker; leading to demixing between the two components within the substrates. The penetration depth of a direct dye, C.I. Direct Red 81, appeared lower than that of the crosslinker in the alkali-pretreated substrates. Pretreatments with NaOH in the range of 4-8 mol/L appeared to create gradients of accessibility within fibers and yarns of lyocell fabrics, with the depth of reagent penetration increasing in the following order: C.I. Direct Red 81 < crosslinker < catalyst.

show abstract

Section: Introductionmentioning

confidence: 99%

Alkali pretreatment and resin finishing of lyocell: Effect of sodium hydroxide pretreatments

Kongdee

Manian

Lenninger

et al. 2009

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

show abstract

“…We examined their effects on later crosslinking with a widely used agent, dimethyloldihydroxyethylene urea (DMDHEU) (Manian et al 2006(Manian et al , 2008. Fabric pieces crosslinked after alkali pretreatment exhibited lower tensile strength, lower abrasion resistance and lower crease recovery as compared to pieces crosslinked without pretreatment, although all pieces were treated with the same crosslinker formulation and all exhibited the same crosslinker content.…”

Section: Introductionmentioning

confidence: 99%

Alkali pretreatments and crosslinking of lyocell fabrics

et al. 2017

Self Cite

View full text Add to dashboard Cite

Lyocell fabrics were pretreated with NaOH, KOH and LiOH and subsequently crosslinked with three urea-formaldehyde based crosslinkers DMDHEU, DMeDHEU and DMU. The mechanical properties varied with the alkali concentration in fabrics crosslinked after pretreatment with 2-8 mol/l NaOH and 4 mol/l LiOH. In fabrics crosslinked after pretreatment with 2-8 mol/l KOH and 1-3 mol/l LiOH, in contrast, the mechanical properties were relatively insensitive to the alkali concentration. The difference in effects is attributed to the alkali influence on the accessibility of crosslinker in fiber structures. The NaOH and 4 mol/l LiOH pretreatments increase the accessibility of crosslinker but the KOH and 1-3 mol/l LiOH pretreatments do not appear to change accessibilities to the same extent. The results underscore the importance of alkali choice and process control in the pretreatments of lyocell. Both NaOH and KOH may be used to good effect. However, lyocell is more sensitive to changes of alkali concentration in NaOH treatments as compared to KOH pretreatments. Thus, the use of NaOH in pretreatments of lyocell will require a greater degree of monitoring and control of alkali concentrations as compared to when KOH is used.

show abstract

“…The micrographs were obtained using a Technai G 2 12 (FEI Company) microscope equipped with a CCD camera (Gatan Bioscan) at 100 kV (Hagage et al 1969;Abu-Rous et al 2006). …”

Section: Transmission Electron Microscopy (Tem)mentioning

confidence: 99%

“…By applying transmission electron microscopy (TEM) to ultra-thin cross-sections of fibers, the main characteristics of the internal morphology of cotton and man-made cellulosic fibers (modal, viscose and lyocell) can be visualized. Lyocell contains only nanopores in the bulk of the fiber with a slight gradient in pore density, and a very porous skin layer (Abu-Rous et al 2006). Fluorescent microscopy can also be used on fiber cross-sections dyed with Uvitex-BHT in order to characterize the pore structure of cotton, lyocell, viscose and modal fibers (Abu-Rous et al 2006, 2007.…”

Section: Introductionmentioning

confidence: 99%

“…Lyocell contains only nanopores in the bulk of the fiber with a slight gradient in pore density, and a very porous skin layer (Abu-Rous et al 2006). Fluorescent microscopy can also be used on fiber cross-sections dyed with Uvitex-BHT in order to characterize the pore structure of cotton, lyocell, viscose and modal fibers (Abu-Rous et al 2006, 2007.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Changes in the intra- and inter-fibrillar structure of lyocell (TENCEL®) fibers caused by NaOH treatment

et al. 2008

Self Cite

View full text Add to dashboard Cite

Some effects of NaOH treatment at concentrations of up to 8 M on (1) the porous structure, (2) the degree of swelling, (3) carboxyl content using methylene blue sorption and 9H-fluoren-2-yl-diazomethane (FDAM) methods, (4) dyeing, (5) the molecular weight distribution measured by gel permeation chromatography (GPC), (6) crystallinity determined by wide angle X-ray diffraction (WAXD) and (7) the tensile properties of lyocell fibers were investigated. The porous structure of fibers was visualised using fluorescence microscopy and transmission electron microscopy (TEM) on fiber cross-sections and was also studied by inversion size exclusion chromatography (ISEC). Mean pore diameter and pore area of fibers were not changed by NaOH treatments. The pore volume increased above 2.5 M NaOH. NaOH-treated samples showed higher dye uptake, higher swelling, but lower carboxyl and moisture content and increased crystallinity. As the NaOH concentration increased, the depth of colour following dyeing with C.I. Direct Red 81 also increased due to deep penetration of alkali into the fiber. In general, fiber properties were distinctly different in the ranges 0 to approximately 3 and 3-8 M NaOH.

show abstract

The influence of alkali pretreatments in lyocell resin finishing—Resin distribution and mechanical properties

Cited by 15 publications

References 16 publications

Alkali pretreatment and resin finishing of lyocell: Effect of sodium hydroxide pretreatments

Alkali pretreatment and resin finishing of lyocell: Effect of sodium hydroxide pretreatments

Alkali pretreatments and crosslinking of lyocell fabrics

Changes in the intra- and inter-fibrillar structure of lyocell (TENCEL®) fibers caused by NaOH treatment

Contact Info

Product

Resources

About