PET Surface Properties affected by low temperature plasma modification

Transcription

1 PET Surface Properties affected by low temperature plasma modification Tarek S. Salem Polymer Interface Department Leibniz Institute for Polymer Research-Dresden Mühlleithen / Vogtland, March Salem@ipfdd.de Poly(ethylene terephthalate) properties xygen plasma pre-treatment Subsequent treatment with polyelectrolytes Textile Printing

2 Poly(ethylene terphthalate) (PET) fabric High tensile strength, dimensional stability Resistance to many chemicals In Blends, PET makes the fabrics more resilient and wrinkle free 2

3 Motivations : Amorphous region rystalline region Morphology of PET fibre rystal structure of poly(ethylene terephthalate) Encylopedia of polymer science and technology 2003 R.H.Peters, the chemistry of fibers, Vol.1, Elseiver publications,1963 3

4 Motivations : Moisture regain : % at RH 65%, 20 o Different classes of dyes Different textiles substrates Fibres& Textiles In eastern Europe April/june 2003, v.11, no.2 (41) Textiles Ink-jet Printer Printing pastes in traditional printing 4

5 bjective : Surface modification of PET fabrics in order to open numerous opportunities for improvement of wetting, printing behavior (substrate-independent printing) without altering the mechanical / physical properties of the bulk materials. 5

6 Strategy Application of low temperature oxygen plasma to endow the PET surface with moieties of polar groups ( -H, -H,..). Such introduced oxygen-containing groups increase the surface free energy and enhance the fabric s wettability, but they can also act as anchor for further surface modifications by weak polyelectrolytes H H Heat + + PET H NH 6

7 Plasma pre treatment Gas inlet Microwave generator 2.45 GHz Tunable power (0-600 W) Excited gas species: Atoms Molecules Ions Photons Electrons Free radicals metastables PET Vacuum pump rosslinking Etching (degradation) Functionalization P-P P M M M P-P-P-P P-P- P-P-P-P P-P-P-P P-P-P-P P-P-P-P- P-P-P P : polymer chain 7

8 XPS Analysis Plasma power [W] Plasma exposure time [s] [at %] [at %]

9 XPS Analysis 1s [ H 2 H 2 ] n c) KLL 1s Si 2s Si 2p 2s =--H = Plasma treated at 300 W 15 s = b) =--H Plasma treated at 100 W 15 s x H y =-- a) - =-- π π* Untreated PET Binding energy [ev] Binding energy [ev]

10 A possible mechanism of plasma functionalization for PET fiber 1 2 (I) (II) H 2 H 2 H Active plasma species H (I) (III) Active plasma species (IV) -H H 2 (II) H (I) 2 H 2 H 2 H 2 H 2 H H H (IV) H 2 H 2 H 2 H 2 H H H 2 H 2 H A.Perwuelz, J. Adhesion Sci.Technol., Vol.20, No. 9, PP.939 ( 2006) 10

11 Zeta-Potential (ζ)( 0 distance z - + Hydrated cation ζ HP Ψ - Shear plane + Hydrated anion IHP Ψ surface - + HP IHP Immobile layer mobile layer - Fabric sample 1 Fabric sample 2 INLET UTLET Streaming channel Lower part Presentation of the electrochemical double layer according to the Gouy-hapman-Stern-Grahame (GSG) model Electrode Electrode.Werner, H.J. Jacobasch, J.Biomater. Sci. Polym.Edn 7 (1995) 1. PTFE foil Lower part Zeta-potential measuring cell for fabrics 11

12 Zeta-Potential (ζ)( H H IEP= ph ζ=0 Smoluchowski equation : ζ = - Us P η εεo L 1 Q R H.J.Jacobasch, F.Simon,.Bellmann, Techn.Messen Sensoren Geräte syst. 63, 447 (1996) 12

13 Wettability measurments on fabrics Water Uptake Water drop absorption time Weight 2 apillarity 1 Wetting Typical wetting curve F Time Textile sample Liquid 13

14 Water drop absorption time Untreated PET Tabs > 600 s Plasma Pre-treated PET Tabs = s 14

15 Roughness measurments Untreated PET Plasma treated 300 W, 30 s Ra= 24,8 µm Ra= 27,3 µm 15

16 Subsequent treatment with polyelectrolytes H H H H 2 N H H H hitosan NH H 3 H NH 2 H 1. Adsorption 2. Dryeing 3. Annealing NH 2 NH 2 NH 2 NH 2 NH 2 NH 3 NH 2 NH NH 3 NH 3 16

17 Zeta-Potential (ζ)( H NH 2 NH 2 NH 2 NH 2 NH 2 H 17

18 XPS Analysis Plasma power [W] Plasma exposure time [s] [at %] [at %] N [at %] hitosan treated

19 Textile printing NH 2 NH 2 NH 2 NH 2 HN NH 2 S 3 Na S 3 Na HN H +.I. Acid Blue 80 Plasma treated PET+hitosan D D D K/S + S 3 - S S Untreated PET+hitosan Wave length (nm) 19

20 utlook 1.xygen plasma pre-treatment confer wettability properties to the PET fabric. 2.XPS, Zeta potential, and wettability measurements results evidence that the formation of new functional groups on the PET surface could be attributed to the oxidation of the poly(ethylene terephthalate) forming fibre. 3. Polar functional groups, introduced during plasma pre-treatment, were considered as anchor groups for adsorption of chitosan, and its further grafting through the heat-induced reactions. 4. Significant changes in PET surface properties after chitosan coating formation were detected by the increase the colour strength after printing with acid dye and electrokinetic measurement, which showed that the modified PET had isoelectric point shifted to higher ph (7.7) 20

21 Acknowledgement 1. Dr.Frank Simon 2. Dr.Mirko Nitschke 3. Dr.Rolf-Dieter Hund 4.Mr. Dieter Pleul 5.Mr. Alfredo lavimontes 6.Mrs.Steffi Uhlmann 7.Mrs.Anja aspari 8.Mrs.Katharina Fink Leibniz Institute for Polymer Research-Dresden e.v. (Germany) ultural Affairs & Mission sector Minstry of higher education ( Egypt) 21