Structure–property relationships for azo disper dyes on polyurethanefibre
Hong-Fei Qian a,*and Xin-Yuan Song b
a College of Textiles and Apparel,Shaoxing University,Shaoxing312000,China
Email:*************
b College of Chemistry and Chemical Engineering,Donghua University,Shanghai,200051, China
Received:14November2008;Accepted:26March2009
Using two ries of monoazo disper dyes,the relationships between the molecular structure of dye and its dyeing properties,such as adsorption behaviour,fastness properties and distribution on polyurethane–polyester blends,were thoroughly investigated.Correlation analysis of experiment data revealed that the partition coefficient between octanol and water(C Log P)is the main factor affecting dye sorption.A greater level of C Log P tends to have a greater isotherm coefficient and better rubbing and washing fastness on polyurethanefibre,as well as a greater distribution ratio between the components of the blend.The dye dipole moment is negatively correlated with various degrees of washing fastness. The dye with two terminal hydroxy groups exhibited notable sorption on the polyuret
hane component and has the largest partition ratio on polyurethane–polyester in the blend.Corresponding regression analysis equations were identified.
Introduction
Polyurethane(PU)fibre is generically referred to as spandex.It is manufactured from glycol and di-isocyanate raw materials using a special spinning method.Thefibre-forming substance is a long-chain synthetic polymer comprising at least85%gmented PU,with both hard and soft gments.The former contain polar groups such as urethane(NHCOO)and ureylene(NHCONH),which can form intermolecular hydrogen bonds to produce a hard domain within which the gments arefixed to each other,yielding a compact structure,whereas the soft gments can move easily and conferflexibility.
PUfibre is ud by blending with otherfibres;covered yarn and core spun yarn are commonly ud forms.Its content in fabric is usually relatively low,but its prence has a great impact on the colour fastness properties of thefibre blend.Although PU is not a new fibre and has a long practical history,there are still some problems to be solved in PU dyeing.One problem is poor fastness properties caud by the stain of the disper dye on the PU components when the PU is part of a bl
end with polyester(PET).Our previous study showed that the disper dyes preferentially dye the PU component of such a blend rather than the PET[1].In order improve the colour fastness of the dyes,colour technologists are interested in identifying dyes which have a good dyeing performance on the PUfibre or which show less staining on the PU components[2–4].Alternatively,reduction cleaning after dyeing or the addition of a special agent during dyeing are other methods commonly ud to reduce staining of the PUfibre.
Detailed investigations of structure–property relationships of azo disper dyes for otherfibres,such as polyester,nylon and acetate,have been carried out[5–8], but similar rearch for PUfibre is rare.Published studies have mainly focud on the dyeing process for the PU fibre or its blends[9,10].This study established the quantitative relationship between the characteristic parameters of the monoazo disper dyes and their sorption properties on the PUfibre by using a method similar to that reported by Telegin et al.[11].The results of the current study may be helpful in the arch for special dyes for PUfibre and in the development of new dyes which show a good performance in the dyeing of elastic fabrics.
Experimental
Materials
The PUfibre(44.4dtex,PTMG type;Lycra)ud in this study was supplied by Invista Fibres Co.Ltd(China).The woven polyester fabric(density220·210;weight 168g⁄m2)was obtained from Nanfang Company(China). Two ries of monoazo disper dyes were lected to examine the relationship between the dye structure and dyeing behaviour.Series1:CI Disper Orange25,CI Disper Red50,CI Disper Orange76,CI Disper Orange61and CI Disper Red145;Series2:CI Disper Brown1,Disper Brown WXF,CI Disper Orange30,CI Disper Orange76and CI Disper Yellow163(Table1). All dyes were obtained from Zhejiang Longsheng Group Co.Ltd(China)in the form of commercially available press cakes and were purified by repeated re-crystallisation in acetone.In order to accurately compare the dyes studied,all dyes were procesd using the same methods.Milling was performed in a laboratory mill(SDF 400,Fukang Chemical Machinery Co.Ltd,China)for the desired time to reach a dispersing rate of4–5in the prence of a dispersant(Diwatex XP-9;Borregaard LignoTech,Norway)of a mass equal to that of the dye. The dispersions were spray-dried by means of a laboratory spray drier(KOPG-3000;Liaoyang Keao Instrument Co. Ltd,China)with inlet and outlet temperatures of120and 70°C,respectively.
doi:10.1111/j.1478-4408.2009.00188.x
Fibre preparation
To remove impurities,the fibre was scoured at 85°C for 30min in a bath containing 2g ⁄l non-ionic surfactant,then thoroughly rind in distilled water and dried in open air.The liquor ratio was 30:1.The woven polyester fabric was scoured with a solution containing 5g ⁄l nonionic surfactant (Peregal O;Hangzhou Electrification Group Chemical Assistant Co.Ltd,China)and 2g ⁄l sodium carbonate at 80°C for 30min,thoroughly washed in water and air-dried at room temperature.
Isotherm measurement
For each dye,dyeing of various concentrations were carried out in a dyeing machine (Rapid,China)at
a constant temperature of 90°C for 90min to reach dyeing equilibrium,which was determined by measuring the dyeing rate isotherm.The pH of the bath was maintained at 5.0using acetate buffer solution.The liquor ratio was 50:1.After dyeing,dyed samples were rind thoroughly in distilled water,blotted with filter paper and dried in a desiccator at room temperature.
Table 1Molecular structure of the disper dyes ud in the study Dye
A
B
N
O 2N
A战争的影响
B
N
肾虚会掉头发吗
N
CH 2CH 3
CH 2CH 2CN
1a CI Disper Orange 25H H 1b CI Disper Red 50Cl H 1c CI Disper Orange 76Cl Cl 1d CI Disper Orange 61Br Br 1e
CI
Disper
下一章2Red 73
CN
H
O 2N
N
CH 2CH 2CN
CH 2CH 3
N
N
1f
CI Disper Red 145
N O 2N
Cl Cl
N N
CH 2CH 2
CH 2CH 2
A
C
B
2a CI Disper Brown 1OH
OH
Cl 2b CI Disper Brown 19COOCH 3COOCH 3H 2c
Disper Orange WXF OCOCH 3CN H 2d (1c)CI Disper Orange 76H CN H 2e
CI Disper Yellow 163CN CN
H
Table 2Characteristic quantum parameters of the disper dyes ud in the study
Dye Molecular
扁担舞
volume (A ˚3)Dipole
moment (D)C Log P 1a 1058.29
7.28 4.261b
1077.647.22 4.971c (2d )1102.69 6.63 5.691d 1122.76 6.83 5.991e 1098.267.84 3.691f 1136.938.23 4.232a 1117.249.18 4.922b 1313.46 6.90 5.942c 1235.23 6.21 5.312e
1159.47
4.55
4.69
Qian and Song Azo disper dyes on polyurethane fibre
The dyed PU fibre was repeatedly extracted using acetone at room temperature until the sample became colourless.The amount of dye sorbed by the PU fibre,denoted as [D]f ,was determined spectrophotometrically (UV-2450;Shimadzu,Japan)by measuring the absorbance of an acetone extract at the maximum wavelength.The residual dye amount in the bath,[D ]s ,was calculated as
the difference between the total amount of dye initially added and the amount in the fibre.
Colour fastness test
To directly compare the colourfast properties of different dyes,fibre was dyed to 1⁄1standard depth.The test methods ud were ISO 105-C06for wash fastness,ISO 105-X12for rubbing fastness and ISO 105-X11for sublimation fastness.
Dye distribution on PU–PET blend
Two ries of disper dyes were ud to dye a PU–PET blend.For convenient measurement of the dye amount on different components,the blend sample consisted of 90%polyester woven fabric and 10%PU fibre to simulate polyester elastic fabric.The mixed sample was immerd into a dyebath con
taining 2%owf dye and with 1g ⁄l ammonium sulphate ud to adjust the pH 5–5.5.Dyeing was started at 30°C.The temperature was incread by 2°C ⁄min to 130°C,maintained for 40min and then cooled by 4°C ⁄min to 60°C.The dyed mixed sample was rind thoroughly in distilled water and parated into two parts which were then dried in a desiccator at room temperature.
Table 3Data measured for all the disper dyes
Dye Isotherm coefficient,K Maximum sorption (mol kg )1)Crock Wash Sublimation fastness (180°C)Partition ratio d ,k Dry Wet N
a
V
b
C
c
1a 1344.080.04923–42433–4 3.541b
3519.550.1144–52433–4 3.571c (2d )4001.910.122–34–52–34–53–44 4.871d 4391.910.114–54–52–34–53–44–5 6.741e 768.460.0311–231–242–33–4 2.391f 1109.680.0251–231–23–42–33–4 2.382a 1378.810.294–54–51–2434–513.932b 2564.850.194–54–534–53–44–59.552c 1504.000.124–54–52–34–53–44–5 4.992e
1021.53
0.028
2–3
4
34–53–4
4–5
3.74
a Staining on nylon
b Staining on visco rayon
c Colour change
d Partition ratio on PU ⁄PET in th
e blend
Table 4Correlation analysis between characteristic dye parameters and measured data a
Isotherm coefficient
Maximum sorption
Crock
Wash S e Blend partition
Dry
Wet
N b
V c
C d
Volume 0.670f
Dipole )0.812g
)0.700e
)0.677f
C Log P
0.773g 0.877g 0.865g
赵帅晶
0.708f
0.722f
0.836g
a Empty cells reprent an abnce of correlation
b Staining on nylon
c Staining on visco rayon
d Colour change微笑正能量的句子
e Sublimation fastness
f Correlation is significant at the 0.05level (two-tailed)
g Correlation is significant at the 0.01level
(two-tailed)
Qian and Song Azo disper dyes on polyurethane fibre
The dyed PU–PET blend was divided into two parts. The PU part was repeatedly extracted using acetone at room temperature and the PET part was extracted by dimethylformamide(DMF)at higher temperature.The dye amount on the two components was determined by measuring the absorbance of the extract solutions.The partition ratio of dyes between the two components was calculated using Eqn1:
k¼
D1ÁV1Áe2ÁW2
D2ÁV2Áe1ÁW1
;ð1Þwhere D1and D2are the absorbance of the PU and polyester extract solutions,V1and V2are the volume of the corresponding extract solutions,e1and e2are the molar extinct coefficients of the dye in acetone and DMF, and W1and W2are the mass of the PU and polyester, respectively.
财务转正申请Calculation of quantum parameters
The characteristic quantum parameters for the dyes were calculated using various soft chemical techniques.The techniques were as follows:Hyperchem version7.5 (Hypercube Inc.,Canada)for the molecular volume, MOPAC(the AM1method)for the dipole moment and the C Log P rver in Cambridgesoft for C Log P,the partition coefficient between octanol and water. Results and Discussion
The calculated characteristic quantum parameters for the dyes are listed in Table2.The dipole moment and C Log P varied greatly.The volume of the Series2dyes was greater than that of Series1.
Qian and Song Azo disper dyes on polyurethanefibre
Measured data and correlation analysis
The isotherms of all the disper dyes were measured (Figure1).The isotherms of every dye are very similar to each other.Dye uptake by thefibre incread with the dye concentration and reached a constant value above a certain dye concentration,which corresponded to the maximum extent of d
ye uptake.At a low dye concentration,the isotherm approximated to the linear type.The isotherm coefficient,K,which was obtained by calculating the slope of the initial linear part of the curve, and other adsorption parameters are listed in Table3. Fastness properties and the partition ratio on the PU–PET blend are also listed in Table3.Correlation analysis between the characteristic parameters and the various data measured was carried out using SPSS version11.5 (SPSS Inc.,Chicago,IL,USA)and the results are listed in Table4.
Relationship between dye structure and adsorption behaviour
The data in Table4reveal that the isotherm coefficient, K,is mainly affected by C Log P,as indicated by the positive correlation.Considering that the affinity of dye forfibre isfinely correlated to Ln K,the equations which reflect the relationship between the Ln K and C Log P were identified by using polynomial regression analysis,as shown in Figure2.
A greater C Log P value means more hydrophobicity of the dye[12]exhibiting the greater Ln K,which implies that this dye has the higher affinity for the PUfibre.This may be attributed to the hydrophobic nature of the PUfibre,which prefer to sorb dyes with more hydrophobicity.
Relationship between structure and fastness properties As expected,the fastness properties of the di
sper dyes on the PUfibre are not good,especially in the ca of staining on nylon.The results demonstrate that both the dry and wet rubbing fastness is positively correlated with C Log P. Washing fastness properties such as staining on nylon and visco rayon and the change rate are negatively correlated with the dye dipole moment,but positively correlated with C Log P.The results for sublimation fastness are consistent with the well-known fact that a larger molecular size confers greater sublimation fastness owing to the stronger intermolecular force.Further regression analysis yielded corresponding quantitative equations,as shown in Figure3.The results in Figure3indicate that the dye with the greater C Log P has the higher crock fastness and change rate,whereas a greater dipole moment leads to poor washing fastness properties.
Relationship between structure and distribution on a
PU–PET blend
The data regarding the distribution of dyes on the PU–PET blend in Table4reveal that a considerable amount of dye was prent on the PU component and heavy staining of the PUfibre occurred during dyeing of the PU–PET blend.This was the ca in all of the dyes.
The partition coefficient between PU and PET exceeded 2.For dye2a,the difference in dye uptake for
the two components was so great that the dye amount sorbed on the PUfibre was over nearly13times that on the PET component.The measured data indicate that the distribution varied greatly with the type of dye.Although correlation analysis revealed that the characteristic parameters have no apparent correlation to the distribution ratio,the tendency of its value to increa with the increasing C Log P was still found from the data in Tables2and 3.With the exception of dye2a,the correlation between the distribution ratio and C Log P was relatively significant,such that the quantitative relationship was obtained by using regression analysis,as shown in Figure4.
Figure4demonstrates that dye2a,which has two terminal hydroxy groups,has a notable sorption on the PU component.This may be becau of the prence of the hydroxy group,which is capable of forming hydrogen bonds with polar groups such as ureylene HNCONH and urethane NHCOO in the polymer chain of the PUfibre. Conclusions
The results of this study indicate that disper dyes with a greater C Log P value have a higher partition coefficient of adsorption isotherms,as well as good rubbing and washing fastness.An increa in the dipole moment of a dye molecule has a negative impact on its washing fastness.Sublimation fastness is mainly affected by molecular size.The distribution ratio of dye on the PU⁄PET blends ems to increa with increasing C Log P value.The dyes with a greater C Log
P value prefer to exhaust more on the PU component than the PET component.Dye2a has notable sorption on the PU component becau of its two terminal hydroxy groups. Acknowledgement
This work was supported by the Natural Science Foundation of Zhenjiang Province under contract grant number Y404314.
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Qian and Song Azo disper dyes on polyurethanefibre
