Selected Properties of Wool Treated by Low-Temperature Plasma

Transcription

1 Dorota Biniaś, Andrzej Włochowicz, Włodzimierz Biniaś Univerity of Bielko-Biała Faculty of Textile Engineering and Environmental Protection Intitute of Textile Engineering and Polymer Material ul. Willowa 2, Bielko-Biała, Poland Selected Propertie of Wool Treated by Low-Temperature Plama Abtract Low-temperature plama treatment i one of the method for phyically modifying the functional and aethetic propertie of textile. Selected propertie of wool textile are changed by the influence of low-temperature plama on the fibre urface layer, acting only on a very mall thickne. The level of change i limited by parameter of the low-temperature plama. Lowering of the dyeing temperature and of water aborption wa achieved. Key word: wool, woollen knitted fabric, low-temperature plama, dyeing temperature, morphology, capillarity, FT-IR, WAXS. Introduction In order to improve certain propertie of fibre and textile, they are modified by phyical treatment. Phyical modification reult in pecific change in the fibre phyical microtructure and it urface propertie changing the functional and aethetic feature of fibre. One uch phyical modification i treatment with low-temperature plama (LTP). Low-temperature plama (LTP) i produced almot excluively in glow dicharge in a gaeou environment. A key property of thi type of plama i the lack of equilibrium between the temperature of the electron and the energy of the un-ionied ga particle. Thi allow the creation of condition in which the temperature of the plama ga remain cloe to that of the environment, while the energy of the electron i ufficient to break intermolecular and covalent bond. Thi property of LTP make it ueful for initiating modification in polymer which are not reitant to high temperature, that i, of almot all fibre-forming polymer [1-3]. The LTP generated in glow dicharge i the ource of: ultraviolet radiation with a wavelength λ of 1 nm, electron with energie of 1 ev, gae in an atomic tate. It ha been etablihed that applying LTP reult in two kind of effect: urface effect (the o-called plama pyrolyi) - occurring in the outer part of the fibre up to 5 nm, depending on the kind of the ga ued; deep effect - which include the production of radical, hydrogenation and change in the polymer network denity. Thee effect occur from 1-5 µm, irrepective of the kind of ga ued [5]. The proce of plama modification i characteried by an interaction between the plama and a thin outer layer of the fibre. It caue urface change in the fibre, and among other effect increae their wettability. In wool, the urface character of plama treatment i limited to a mall part of the fibre, in relation both to it ma and volume. Phyical propertie uch a the fibre friction coefficient, dye diffuion, etc. depend on the highly-networked layer known a the epicuticle. Modifying thi layer, without cauing change in the wool cortex, facilitate and accelerate ome technological procee, including the dyeing of fibre [1]. The aim of our work wa to carry out by LTP the dyeing proce at coniderably lower temperature than thoe conventionally ued (from 9 C to C). Thi could be done by LTP treatment of wool. In addition, the product obtained from the LTP-treated fibre hould be characteried by better water aborption. Object of Reearch, Proceing and Meauring Method Woollen knitted fabric with interlock weave and an area weight of g/m2 were the tet object. The wool coniting of the knitted fabric wa treated with LTP in an air environment with the following parameter contant over time: air flow - 1 l/ h initial preure mbar final preure mbar ditance between the electrode - 18 cm wool urface treated with plama cm2 The energy parameter (power, time) of the plama treatment for each ample are hown in Table 1 and 2. The LTP treatment of the woollen knitted fabric were carried out at the Textile Reearch Intitute in Łódź, Poland. For examining the ample treated with plama, the following technique were ued: IR pectrocopy, wide-angle X-ray cattering (WAXS), canning electron microcopy (SEM). Water aborption, capillarity and dyeing with an acid dye (Alizarinbrillantreinblau) were alo examined. A ample of woollen knitted fabric which wa not modified with plama wa ued for comparion. The IR pectrocopy examination wa conducted in the tranmiion technique, uing a MAGNA IR 86 pectrophotome- Table 1. Parameter of plama treatment for erie 1; the proceing wa performed at contant power value of W. Time of LTP treatment, Table 2. Parameter of plama treatment for erie 2; the proceing wa performed at contant time, over 6. Time of LTP treatment, FIBRES & TEXTILES in Eatern Europe April / June 24, Vol.,. 2 (46)

2 ter from Nicolet. Fibre were taken out of the ample, then cut and preed in a KBr tablet at a preure of about 1 MPa. The wide-angle X-ray cattering (WAXS) examination wa conducted in a deflection angle range of 4 to 4, with a.1 tep and 2-econd impule counting, uing a HZG-4 diffractometer, CuK α radiation, an accelerating voltage of 3 kv and an anode current intenity of 2 ma. Beam monochromatiation wa achieved by uing a nickel filter and an impule height analyer. A cintillating counter wa ued a detector. The morphology of wool urface wa examined uing a JSM 55 LV canning electron microcope from Jeol. Obervation were conducted with an accelerating voltage of 1 kv and magnification of 2, 5 and 1, Figure 1. Fragment of tranmiion pectra of wool fibre in the 3-28 cm range of IR aborption by group with the C-H ocillator; - pectrum for wool not modified with plama,,,,, - IR pectra for wool ample treated with LTP, with an increaing value of the electric power of the plama and contant time (Table 2). 285 Water aborption and capillarity were determined in accordance with Polih Standard [17,18]. Dyeing wa carried out in order to ae the influence of LTP treatment of wool on it ability to exhaut a dye from the dyebath. The proce wa conducted for elected ample in one dyebath. In addition, UV-Vi pectra of dyeing intenity were obtained by a Hitachi 21 pectrophotometer equipped with an RSA-Hi-2 labphere. Crucial for the proce wa the poibility to lower the dyeing temperature a far down a 6 C Reult An analyi of IR tranmiion pectra reveal that the greatet change occur in the area of aborption by group containing the C-H ocillator. Figure 1 how the diappearance of the 294 cm and 285 cm peak. The aborption area in thee range correpond to the -CH 3 and -CH 2 - ocillator. Thi mean that thee group are oxidied during LTP treatment. At the ame time, hardly any change are oberved in the 1845 cm aborption area characteritic of the amide I and amide II band, which are the reult of aborption by the baic link of the keratin chain, that i, by -CO-NH- (Figure 2). Thee phenomena are accompanied by a light increae in aborption within the cm area, which i characteritic of the O-H and N-H group (Figure 3). The pectrum change oberved after LTP treatment may be explained by urface Figure 2. Fragment of tranmiion pectra of wool fibre in the 1845 cm range of IR aborption by group with the CO-NH- ocillator for the ample:,,,, and *D *D *D *D *D *D Figure 3. Fragment of tranmiion pectra of wool fibre in the cm range of IR aborption by group with the O-H, N-H ocillator. Spectrum hape change in relation to the intenity of plama treatment (ample,,,, and ). FIBRES & TEXTILES in Eatern Europe April / June 24, Vol.,. 2 (46) 59

3 oxidation of the -CH 3 and -CH 2 - group characteritic of the outide group of α-amino acid. IR examination clearly reveal that the treatment i limited to the urface only. A dominant proce i the oxidation of hydrophobic aliphatic chain which originate in the outide group of α-amino acid and probably of the lipid connected with the fibre urface. However, it hould be emphaied that the IR examination wa ucceful, notwithtanding the fact that it i a volumetric tet technique, wherea the change occur only in the urface layer. Thi phenomenon prove the trength of the change induced by LTP treatment. The wide-angle X-ray cattering examination wa conducted on elected ample of knitted wool, both treated with plama and unmodified. Exemplary Intenity (1) (5) (1), (5) - crytalline peak amorphu halo Figure 4. Peak deconvolution of the WAXS profile in the wool not modified with plama. 3 2 Table 3. Reult of WAXS invetigation. 25 (1) (5) 6 Degree of crytallinity, % Crytallite ize D (1), Å Table 4. Reult of meauring water aborption and capillarity for erie 1. Water aborption, % Capillarity, mm Table 5. Reult of meauring water aborption and capillarity for erie 2. Water aborption, % Capillarity, mm Intenity Figure 5. Diffraction WAXS for ample of not modified with plama (), for wool ample treated with LTP 4,6, 11 (Table 1). run are preented in Figure 4 and 5, and the crytallinity parameter obtained in Table 3. The reult of examining the crytallinity level and the ize of crytal area (Table 3) do not prove any direct influence of LTP treatment on the upermolecular tructure of wool. The SEM analyi of urface morphology reveal light change which occur on the urface of wool fibre a a reult of plama modification. The riing parameter of LTP treatment (time and power, or the total energy) lead to a light increae in thee change cauing a rounding of cale, microcrack, recee and tiny groove, all caued by the etching of the material. SEM micrograph of wool fibre after plama modification are hown in Figure 6-9. The mot important effect of LTP treatment of wool i the change in the 2 character of the wool fibre urface from hydrophobic to hydrophilic. The water aborption meaurement reveal the ubtantial influence of the LTP treatment on the aborption value for all ample. An increae of more than 5 time wa oberved between ample. (not modified) and ample 1, for which the water aborption i 692%. The value grow gradually with intenifying the plama treatment, a far a 81% for ample 11 (howing the greatet influence of the plama parameter). Similar reult of meauring water aborption are obtained for ample of the econd erie. When comparing the energy of plama treatment a well a the value of water aborption between both erie, one can oberve a relationhip howing that the improvement of water aborption depend to an approximately FIBRES & TEXTILES in Eatern Europe April / June 24, Vol.,. 2 (46)

4 imilar degree on the time and power of the LTP treatment. Figure 6. SEM micrograph of the urface of a wool fibre not modified with plama, magnification 2. Figure 8. SEM micrograph of the urface of wool fibre after plama treatment, ample 11, magnification 5. Figure 7. SEM micrograph of the urface of wool fibre after plama treatment, ample 11, magnification 2. Figure 9. SEM micrograph of the urface of a wool fibre after plama treatment, ample 1, magnification 5. 9 Water aborption, % Time of plama, Figure 1. Water aborption growing in relation to time of plama treatment. 8 Water aborption, % Figure 11. Water aborption growing in relation to energy of plama treatment. FIBRES & TEXTILES in Eatern Europe April / June 24, Vol.,. 2 (46) Analying the water aborption and capillarity of the ample teted in dependence on the plama energy ued for proceing the ample, it can be noted that at mall energy doe, the increae in the given property are large, wherea at higher doe the increae eentially lower. The boundary between high and low enitivity to plama treatment i clearly viible, and different for water aborption and capillarity. The explanation may be that, up to a given limit of plama energy, the majority of the poible change occur, and further treatment i not o efficient. The reult of meauring the capillarity of the woollen knitted fabric prove that thi property i particularly affected by LTP treatment. Before the treatment, the hydrophobic layer on the epicuticle urface prevent any wetting of the fibre urface and thu of the knitted product. The ample not modified with plama did not reveal any capillary action. The mallet doe of LTP decreae or detroy the hydrophobic layer. The hydrophilic group created on the urface a a reult of the treatment affect the value of urface tenion and allow for the wetting of fibre and at the ame of the woollen product. Increaing the plama treatment parameter reult in increaing capillarity, from 53 mm to 172 mm for ample in erie 1, and from mm to 7 mm for ample in erie 2. The capillarity of the woollen knitted fabric i ubtantially dependent on the LTP modification and it parameter. The reult of meauring water aborption and capillarity are hown in Table 4 and 5, and Figure. It hould be emphaied that both the water aborption and the capillarity depend on the plama energy to different degree. Beginning with zero and up to a certain energy value, the change of both above-mentioned quantitie are ignificant. Above thi value, the influence of LTP i everal time lower. The proce of dyeing at 6 C, conducted for elected ample of woollen knitted fabric previouly treated with LTP a well a for an unmodified ample, prove that the dye i better exhauted from dyebath by the ample modified with plama. Thee latter alo have a deeper colour hade and aborb dye at 6 C much better. The influence of plama treatment on the dyeing intenity of 61

5 the ample teted i clearly viible from the UV-Vi pectra preented in Figure. The pectra were obtained with the ue of a Hitachi 21 pectrophotometer equipped with an RSA-Hi-2 labphere. The lowet energy parameter of plama treatment which we ued reulted in the lowering or even the detruction of the barrier layer. Thi allow for dyeing wool at temperature lower than thoe conventionally ued. When wahed after dyeing, the LTP-treated ample of both erie alo prove to have bound the dye better than in the unmodified ample. Concluion LTP damage an ultra-thin hydrophobic layer on the protective urface of the fibre. Thi proce occur only on the urface, and doe not damage the inner tructure of keratine. Removing the barrier layer reult in increaed orption of humidity and dye and improved wettability of the knitted woollen fabric. Thee propertie are advantageou for textile, and in particular they improve the comfort of wearing clothe. Acknowledgement The author wih to thank Dr. Witold Rakowki, Textile Reearch Intitute, Łódź, for allowing them to conduct tet of treating woollen knitted fabric with plama. Reference G.A. Byrne, K.C. Brown: J. Soc. Dyer Col, 86, 1972, p J.D. Fale, A. Bradley, R.E. Howe: Reearch 1 and Development, vol. 3, 1976, p E.J. Lawton: J. Appl. Polym. Sci.,, 1974, p W. Rakowki, W. Lota: Plama modification 4 2 of wool (in Polih), Conference Proceeding, Ekotextil, 1994, p W. Rakowki, M. Okoniewki, K. Barto, J. Zawadzki: Textile product modification Time of plama, 6, 1982, p , p (in Polih). Przegląd Włókienniczy, vol. 5, 6. W. Rakowki: Plama treatment of wool Figure. Capillarity growing in relation to time of plama treatment. - from lab curioity to indutrial reality. Proceeding of the 9 th International Wool Textile Reearch Conference, Biella, 1995, p K.M. Byrne, W. Rakowki, A. Ryder, S.B. Havi: The influence of glow dicharge plama treatment on the wool production 1 pipeline. Proceeding of the 9th International Wool Textile Reearch Conference, Biella, 1995, p W. Rakowki: Application of low-temperature plama in preparation of woollen 6 fabric for printing (in Polih). Ph.D. Thei, 4 2 Technical Univerity of Łódź, C.D. Radu, M.D. Caraiman, P. Kieken: Development in wool plama treatment Proceeding of the 1th International W Wool Textile Reearch Conference, 26 vember 2, Aachen, Germany. 1. R. Fellenberg: Plama-upported hrinkproofing of wool top. Ibid. Figure. Capillarity growing in relation to energy of plama treatment. 11. H. Thoma, T. Merten, V. Moner, H. Höcker: Fundamental of plama-upported hrinkproofing of wool: elective modification of the fibre urface and reulting technological propertie. Ibid.. D. Theirich, F. Oenberg, J. Engemann: Microwave plama treatment of wool proce development and proce control. Ibid..5. F. Förter, E. Prinz, B. Marten: Baic invetigation on atmopheric preure barrier dicharge for hrinkproofing of.3 wool top. Ibid.. B. Janen, F. Kümmeler, H. Thoma, H..1 B. Müller: New rein for hrinkproofing of plama-treated wool. Ibid.. H. Höcker: Fundamental of plama-upported -.1 hrinkproofing of wool: concluding remark. Ibid. nm. Polih Standard PN /P Figure. Fragment of pectra of dyed ample in the 4-8 nm range of UV-Vi 17. Polih Standard PN /P remiion; - UV-Vi pectra for wool not modified with plama; 1, 4, 9, 11, - UV-Vi pectra for wool ample treated with LTP. Received.1.23 Reviewed Capillarity, mm Capillarity, mm R 62 FIBRES & TEXTILES in Eatern Europe April / June 24, Vol.,. 2 (46)