influence of nonwovens structure on antibacterial ... · web formation : 3d fibers orientation (...

INFLUENCE OF NONWOVENS STRUCTURE ON ANTIBACTERIAL FUNCTIONALIZATION

G. Bénistant, A. Perwuelz, C. Campagne,P. Vroman

ENSAIT, GEMTEX, Roubaix, Univ. Lille Nord de France, France

With the support of the French Nord Pas de Calais region

May 06, 2010 IFATCC Stresa 2

nonwovens

medical and cosmetics

filtration

agriculture


Nonwovens process : melt-spun

Source :nonwoven-us.com

Web formation : multilayers ( thickness: 0.2 to 0.4 mm)

Fibers : Polypropylene PP, 15 to 20µm SB – 3 to 5 µm MB

Spun bond : SB

Meltblown : MB


Nonwoven process: drylaid: carding-napping- spunlacing

Card: Web formation

Cross-lapper

Needleloom: Pre-bonding

Hydroentanglement: Web bonding

Dryer: 100°C

Web formation : 3D fibers orientation ( thickness: 0.5 to 1.2 mm)

Fibers: all fiber nature > 1 dtex


Nonwoven process: drylaid: carding-napping- spunlacing

❚  Standart PET fibers : 10.6 µm

❚  Development of very fine fiber made nonwoven: VF Using 50/50 PA6/PET PieWedge bicomponent splittable fibers

❙  16 segment fibers

Using nonwoven pilot line (IFTH Tourcoing France) Splitting with high pressure hydroentanglement

❙  Produce sub microfibers

Pie-wedge Before splitting: 20 µm After splitting: 4-5 µm


❚  Nonwovens may be produced from differents ways

Objectives

❚  Effect of the nonwoven structure on the functionalization process ❙  Changes in nonwoven structure ❙  Organization of the functional molecules at the fiber surface ( fibre

nature, textile structure) ❙  Functional properties

❚  Study of antibacterial functionalization with 4 differents nonwovens


Non wovens: Spun Melt / drylaid - PP/PET

SB MB PET VF

technology Spun Bond MeltBlown Carding-napping-hydroentanglement

Carding-napping-hydroentanglement

fibres PP 17,5 µm

PP 3,2 µm

PET 10,6 µm

PET /PA piewedge 4,7 µm

g/m2 25 g/m2 30 g/m2 207 g/m2 177 g/m2

Porosity : 88% to 90 %


Nonwoven treatment

❚  Antibacterial solution ❙  Concentration 10% ❙  nature : quaternary ammonium (quats) ❙  binder 2%

❚  treatment ❙  Padding ❙  Evaporation T=110°C for 2mn ❙  curing at T= 150°C for 2mn

❚  Post treatment ❙  washing at 37°C up to 4 cycles ❙  Liquor ratio 1/100 – distilled water


Treatment characterisation

❚  Variation of the nonwoven structure ❙  Compacity deduced from thickness:th M mass per unit area ρ polymer volumic mass

ε porosity ❙  Air permeability test: ISO 9237 Textest FX3300 at 200Pa

❚  Organization of the quats at fiber surface ❙  Zeta potential Streaming potential method KCl 10-3mol/l Zeta CAD apparatus

thMc.

1ρ

ε =−=


Treatment characterisation : Porosity permeability

0%

5%

10%

15%

20%

SB MB PET VF0

500

1000

1500

2000

2500

3000

3500compacity before

compacity after

air permeability before

air permeability after

�No significative modification of the nonwoven structure after antibacterial treatment


Treatment characterisation : Zeta potential

-100

-80

-60

-40

-20

0

20

40

60

80

2 4 6 8 10

pH

PET sample

PP MB sample

zeta potential(mV)

Negative zeta potential

PP or PET nonwovens



-100

-80

-60

-40

-20

0

20

40

60

80

2 4 6 8 10

pH

PET treated sample

PET sample

PP MB sample

PP MB treated sample

zeta potential(mV)

Negative zeta potential

PP or PET nonwovens

Positive zeta potential

�quaternary ammonium

zeta potential depends on pH value

Positive value: quats

Negative values: PP or PET

�fiber surface not fully covered by quats

Small differences between PET and PP fibers



SB MB PET VF IEP 6,7 7,3 8,3 7 pH=5 23 42 61 17 pH=8 -19 -22 12 -22

-100

-80

-60

-40

-20

0

20

40

60

80

2 4 6 8 10

pH

PET treated sample

PET sample

PP MB sample

PP MB treated sample

zeta potential(mV)

� Very similar organization of the quats at the fiber surface: fibers are not fully recovered

- Both polymers: PP and PET

- Both structures : SpunMelt and Carded


Antibacterial characterization

❚  Method JIS Z 2801 2000 (Staphylococcus aureus ATCC 6538) ❚  0,4 ml bacterial suspension ( 2.5 to 10 . 105 UFC/ml) deposit on a

5cmx5cm nonwoven sample ❚  3 treated samples / 3 untreated samples ❚  Incubation : 35°C ± 1°C , RH>90% ❚  Bacteria number Results : A at t=0

B untreated sample at t C treated sample at t

❚  Antibacterial activity after incubation during t time

R =log (B/A) – log (C/A) = log B/C


Antibacterial characterization : effect of washing

0

1

2

3

4

5

5 min 15 min 30 min 1 h 2 hincubation time

antib

acte

rial a

ctiv

ity

1 washing cycle3 washing cycles

Effect of washing cycle on antibacterial activity of SB PP

Remaining quats in water measured (HPLC)

- After one washing cycle : 56 ppm

- After 3 washing cycles: 0ppm (<1ppm)

•  Unlinked quats are responsible for good antibacterial activity

•  Linked quats generates less antibacterial activity


Antibacterial characterization : Nature of nonwoven

Fiber diameter 17,5 µm 3,2 µm 10,6 µm 4,7 µm

fibers surface area*

3 m2 20 m2 28 m2 49 m2

0

1

2

3

4

5

SB MB PET VF

antib

acte

rial a

ctiv

ity

5 min

15 min

30 min

1 h

2 h

After last washing , quats concentration < 1ppm

Total fibers surface area for 1m2 fabric

After 2h incubation all the samples have 4log reduction bacterial population

Due to higher specific surface area , finer fibers nonwovens have better AB activity


conclusion

❚  Nonwoven structures: ❙  Fibre nature ❙  Fiber fineness ❙  Nonwoven process

❚  Functionalization ❙  Small change in pore structure ❙  Zeta potential is a tool to get information on the homogeneity of the

treatment

❚  Antibacterial properties ❙  Links between the quaternary ammonium and the fibers ❙  If antibacterial molecules are linked, Antibacterial activity is LOG 4 bacteria reduction in 2 hours Antibacterial activity depends on the fiber fineness à specific surface area

in contact with bacterias


❚  Thank you for your attention….

influence of nonwovens structure on antibacterial ... · web formation : 3d fibers orientation (...

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