DSpace at VNU: P'lasma-Induced Graft Polymerization of Acrylic Acid onto Poly(ethylene terephthalate) Films: Hydrophilic Modification

v w u . JOURNÁL 0 F SCIENCE. Nat., Sci., & Tech., T.XXIII, NọỊ, 2007

PLASMA-INDUCED GRAFT POLYMERIZATION OF ACRYLIC ACID
ONTO POLY(ETHYLENE TEREPHTHALATE) FILMS:
HYDROPHILIC MODIFICATION
Nguyen Kien Cuong
D ep a rtm en t o fC h em istry, College o f Science, V N U

ABSTRACT. A complete and permanent hydrophilic modiĩication of poly
(ethyleneterephthalate) (PET) ĩilms is achieved by argon-plasma irradiation,
subsequently graíting acrylic acid (AA) in vapor phase onto their suríace. Both Ar
plasma irradiation alone and post graíting AA rendered a complete hydrophilicity to
PET surtaces. Hovvever, the hydrophilicity of the PET suríace, only treated with the
Ar plasma, is not permanent. In contrast, PET íilms, irradiated by the Ar plasma,
exposed to air, and subsequently gratted with AA monomer, are permanently
hydrophilic. Degradation of polymer chains on the plasma-irradiated surtace is
proportional to time of exposure. Electron spectroscopy for chemical anaỉysis (ESCA)
coníirmed the grafting of AA onto the íilm suríace, whỉch results ỉn a large amount of
incorporated oxygen-containing íunctional groups like carboxylic (O ũ C' = O) and
carbonyl (C' = O). The morphology of graíted suríaces, observed by scanning
electron microscopy (SEM), displays some large area of microporosity compared to
relative smooth morphology of the control one. Gratted íunctional groups and suríace
microporous structure are the main íactors to enhance hydrophilicity of the PET ĩilms.

Keywords: Plasma-induced graft polymerization, polymer degradation, oxygencontaining íunctional groups, hydrophilicity, microporosity and eiectron spectroscopy
ỉorchemical analysis (ESCA).

1. In tr o d u c tio n
P olym eric m a te ria ls hold considerable in te re st in th e íĩeld of b io m aterials for
s c ie n tis ts in re c e n t y ears. T issu e en g in eerin g culture, m in im izin g p ro tein adso rp tio n to
p re v e n t m em b ran e-fo u lin g for p ro tein u ltra filtra tio n , im m obilization of biologically

activ e m olecules a n d liv in g cells, etc., are r a th e r closely re la te d to hydrophilic
c h a ra c te rs of polym er su rfaces [1-3]. S urface hydrophilicity of th e polym er can be
achiev ed by th e in co rp o ratio n of oxygen-containing fu n ctio n al groups, such as — COOH
a n d — OH, w hich a re u su a lly n o t coupled w ith m olecular ch ain s of th e polym er surface.
S u ría c e m o difications could en h an ce m echanical in terlocking, a n d cre a te functional
groups, im p ro v in g w e ttin g an d /o r chem ical bonding of a polym er surface. S ynthetic
polym ers, th erefo re, o ften re q u ire selective m odiíĩcations to in tro d u ce speciíìc
functional groups onto suríaces for proper purposes, ex. binding of biomolecular, gas
b a rrie r, etc.
T h e co n v en tio n al m eth o d s (wet chem istry) for th e hydrophilic m odiíìcation of
polym er s u ría c e s h av e b een períorm ed by various chem ical tre a tm e n ts , usually
accom panied by d am a g in g polym er bulk, hence affecting its p ro p erties. In c o n tra st to

47


48

N guyen Kien C uong

th e w et ch em istry , th e polym er 8urface, exposed to p la sm a , can be m odiíĩed to en h an ce
its hydrophilicity, co m p atib ility an d bioĩunctionality. M oreover, th e m odiíìed su rface is,
in gen eral, coníìned to a top-surface lay er less th a n several h u n d r e d n a n o m eters
th ro u g h polym er th ick n ess. T hereíore, d esirab le p ro p e rtie s of b u lk lay ers a re u su a lly
m ain tain ed . H ow ever, on m ost polym er surfaces, th e g ain ed h y d ro p h ilicity is u su a lly
not p e rm a n e n t, a n d d isa p p e a rs or d im in ish es s ig n iíĩc a n tly a fte r only p la sm a
irra d ia tio n . T he irra d ia te d surface g rad u ally re s to re s its h y d ro p h o b icity d u e to
ừ a g m e n te d low -polym er c h a in s on 8urface layers, te n d in g to re o rie n t into b u lk layers.
T his resu lte d in d ecrease in a n u m b er of fu n ctio n a l groups, th e re b y d e c re a sin g its
hydrophilicity. P o st-g ra ft copolyraerization can fìx ra d ic a ls by g ra ftin g a hydrophilic

m onom er onto th e irra d ia te d su ríace, therefore, ra is in g th e lifetim e of su rface
hydrophilicity. In ad d itio n , th e g ra ítin g of a speciíìc m onom er m a k e s a su rface m odified
w ith su ita b le chem ical fu n ctio n ality for b io m aterial a p p lic a tio n s [4-7].
In previous p a p e r [8], hydrophilic im p ro v em en t of P E T ílb ers in m oisture
ab so rp tio n an d d yeing p erío rm an ce h a s been re p o rte d . A bsorption e n h a n c e m e n t are
due to th e existence of carboxyl groups: 0 —
= o , in c o rp o rated on to P E T fĩber
su rĩaces, íu rth e rm o re , th e ccn d itions of th e p la sm a irra d ia tio n aa \vell as graítpolyraerization h av e co n sid erab ly eíTects on th e h y d ro p h ilic d u ra b ility of P E T fibers.

c

This paper describes PET íìlms, irrad iated w ith a m ix tu re of in e rt g a se s like
heliu m /arg o n (He/Ar) a t p re ssu re of o n e-atm o sp h ere, th e n su b se q u e n tly graítpolym erized w ith acrylic acid in v apor to en h an ce th e irs h y d ro p h ilic d u ra b ility over
tim e. EíTects of irra d ia tio n tim e on a w eigh loss ratio a n d g ra ítin g d egree of P E T ’s films
w ere in v estig ated . O xygen-containing functional gro u p s, c h a ra c te riz e d by electron
spectroscopy for chem ical a n aly sis (ESCA), w ere u se d to ro u g h ly e s tim a te hydrophilic
cap ab ility of th e g ra fte d surface. S urface m orphology of th e g rafted su rface was
observed by sc an n in g electro n m icroscopy (SEM). In ílu e n c e of th e g rafted íunctional
groups an d su ría ce m orphology upon surface h y d ro p h ilicity w ill be discussed.

2. E x p e rim e n ta l P ro c e d u re s
— C 3 —— -

2.1. Sam ple p rep aration

Ị \ » \ N e . N_,

Rị

— c

= 0

m olecular

bonds

w h en

Ito c tro n i

M*

bond,

sy ram etrically-bonded
to
an
aro m atic ring, seem to be stable.
B esides, th e re a re — C H 2 — C H 2
bonds \vith low er b o n d in g energy.
H ence,
th e
d e g ra d a tio n
of
m olecular c h ain s on its surface
m ig h t occur a t c — H a n d c — c

r a d lc a ls

c"

©

In P E T fílm s tru c tu re , two

groups of 0

R #

lon*
o l» c tro n lc
e x c lte d p a r t id i

uv-mdlatlon
1VH
1 1X1 1 *

® ỉ

g c M*

R* ©

Substrate
e lo c tro d ỡ

lúncdonal

groups

r. f. pow er

th e
Fig.1. Principle o f plasma reaction insỉde electrodes
V N U . J o u rn a ì o Ị S c ie n c e , N a i., S ci .đc T e ch ., TJOQỈỈ, N 0Ỉ , 20)7


Plasm a - Induced graft poíym crization o f acrylic acid onto.

49

m o lecu lar ch ain abso rb s p lasm a-en erg y from a c tiv a te d species an d u ltra v io le t rays
d u rin g th e p lasm a irra d ia tio n . The principle of p lasm a reac tio n o ccurring betw een two
electro d es is described in íìg u re 1. Glow discharge p la sm a a t o n e-atm o sp h ere w as
g e n e ra te d in a p la sm a re ac to r (m a n u ía ctu red by P e a rl Kogyo Co. L td, O saka, J a p a n )
cou p led w ith p a ra lle l p la te electrodes, w hich w ere covered by dielectric b arrierceram ic, an d o p e ra tin g a t rad io írequency of 13.56 M Hz. A P E T film sam p le of 0.2 mm
in th ic k n e ss, provided by A sah i G lass F ibers Co. Ltd. (Ja p a n ), w as placed betw een two
electro d es, an d th e n irra d ia te d w ith th e m ix tu re of H e/ A r in e rt gases, introduced by
th e c o n s ta n t flow ra te of 850m l /150m l m in 1 (STP), an d in tro d u ced into a plasm a
ch a m b e r. Irra d ia te d from 10 sec to 3 m in, w ith p lasm a p o w er-d en sity of 1.75 w /cm 2, a t
electro d e su ría c e te m p e ra tu re of ab o u t 70°c • 80°c, each sam p le w as rem oved from th e
p la sm a ch am ber, th e n im m ed iately w eighted to e s tim a te d e g rad atio n State of surfacelay ers. T he irra d ia te d sam p le vvas th e n grafted w ith acrylic acid (AA) of 99.5% conc. in
a glass tu b e e v ac u a te d to 133 Pa a t two level of c o n s ta n t te m p e ra tu re : 6 0 ° c as w ell as
70°C; th e g ra ftin g process la ste d for 8 h o u rs an d 1 h o u r, respectively. T ak en from th e
g lass tu b e, th e sam p le w as e x tra c te d by hot m eth an o l in a S oxhlet e x tra c to r for 2 h ours
to rem ove u n re a c te d re m a in in g m onom er an d hom opolym ers.

2.2. ESCA ch a ra cteriza tio n of m od iíìed surface
ESCA m e a s u re m e n t w as períorm ed on a K rato s ESCA -3300 spectro m eter,
em ploying M gK a (1253.6 eV) X-ray source. T he electro n tak e-o ff an g le w as ad ju sted

a ro u n d 6 0 °c w ith resp ect to th e íìlm suríace. T he p re ss u re in th e an a ly sis ch am b er was
m a in ta in e d a t a b o u t 1 0 5 P a du rin g th e d a ta acq u isitio n . T he X -ray source w as ru n a t
th e anode voltage of 8 kV a n d c u rre n t of 30 mA.

2.3. S urface m orp h ology ob served by SEM
S u ría c e m orphology o f th e g rafted íílm s w as observed by a scan n in g electron
microscope (SEM ), m odel J E O L JSM -5200. F or b e tte r electric conductivity, a sam p le’s
su rface w as coated w ith th in gold lay er before th e ex am in atio n . T he observation w as
perío rm ed to d e te rm in e th e q u ality of polym er depositions, a n d especially to check
w h e th e r m icropores a p p e a r on th e g rafted surface.

3. R e su lts a n d D iscu ssio n
3.1 D egrad ation o f plasm a-irradiated su ríace
T h e d e g ra d a tio n of th e film su ríace irra d ia te d by p la sm a seem s to be
p red o m in a n t effects of th e d isch arge in tera ctio n betvveen its su ríace an d activ ated
species like ions, p a rtic le s, etc. T his process led to an a lm o st coraplete breakdow n of c
— H o r c — c bonds, p ro d u cin g carbon rad icals on irra d ia te đ su rfaces. T he polym er
d eg rad atio n can be describ ed a s follows:

V N U . J o u r n a l o f S cien c e. N a t.. S ci.,& T e c h .. T X a i l . N al , 2 0 0 7


50

Nguyen Kicn Cuoĩĩtg

r

ọ

9H

Hl

II / ^ r \
11
I I
o — c - \ 0 ) —c — o — c — c - H

Plasma
irradiaíion

9

9

H

H

o - c - \/ ế0~ /\ - c!L—o - c -' c

H -

Radical

'

H

c

W here: • is a ra d ic a l grow n by th e d e g ra d a tio n of a m olecular ch ain on th e P E T
surface. T h e p o ly m er d e g ra d a tio n , c h a ra c te riz e d by w eight-loss ratio , w as calculated in
th e following ex p ressio n :

WL(%) =. 100 *(W,- w0)/w0

(1)

W here: WL (%) is th e w eig h t-loss ra tio ; W0 a n d W] a re th e w eig h t of a sam p le
beíore a n d a fte r th e G D P tre a tm e n t. T h e m in u s m a r k Ĩ8 d enoted as th e w eight loss of
th e m olecular c h a in s d u e to th e d e g rad atio n .
The
d e g ra d a tio n
of
th e
m olecular ch a in s on th e irra d ia te d
su rface lay e rs v e rsu s th e tim e of
exposure 18 in d ic a te d in th e Fig. 2. It
18 clearly th a t th e w e ig h t loss ratio ,
in d ic a tin g
th e
level
of
th e
d eg rad atio n , w e n t u p w ith f u rth e r
exposure tim e. L a rg e d isp e rsio n of
th e vveight loss is a sc rib e d to th e
effect of th e d e n s ity of a c tiv a te d

species, w hich collided w ith th e film
8urface as w ell a s th e cro ss-lin k in g
of rad ica ls g e n e ra te d on th e P E T
su rface
d u rin g
th e
p la sm a
irra d ia tio n . T h e s im ila r re s u lts h av e

Exposure tim e (sec)

also b een found in th e re p o rt of
Flg. 2. Degradation o f polym er surtace versus
Y asu d a et. aỉ.[9 ]. E xposed to a ir,
the tim e of irradiation
th e se rad icals w ere re a c te d w ith
oxygen in a ir to p ro d u ce p ero x id es a n d (— CO OH) h ydroperoxides. T h ese peroxides,
b eing in itia to rs for th e s u b s e q u e n t g ra ft p o ly m eriza tio n w ere form ed as following
reactions:

f

oII
o
II t r r \ 1I

■ o -c -(0

H
r o II

oII
H
Hi
I I
I I H^ Exposuredto
Air
rz\ I
I
) - c — o — c — c - - --■o—c (0/ c o c C-H

HO O

H-

V N U . J o u r n a l o ỊS c ie n c e . N a t.. Sci .A T e c h .. T x a i l . N 01. 20(7


51

Plasm a - Induccd graft polym erization o f acrylic acid onto..

3.2 E ữ ects o f th e ex p o su re tlm e on g ra ftin g d eg ree
O w ing to th e rm a lly -in d u c e d d e g ra d a tio n co in cid en t w ith th e p resen ce of th e AA
m ono m er in vapor, c o • a n d • OH rad icals, decom posed from th e hydroperoxides, w ere
th e n graft- polym erized in a g lass tu b e, ev acu ated to 133 P a a t te m p e ra tu re of 6 0 °c for
8 h rs a s well a s 7 0 °c for 1 h r. G ra fte d w ith th e AA m onom er of 99.5% conc., th e se c o *
ra d ic a ls, in itia lly serv in g a s a c tiv a te sites, re a c te d w ith th e m onom er to cre a te
copolym ers w hile *OH ra d ic a ls, also re a c te d w ith th e sa m e m onom er, w ere changed
in to hom opolym ers.

o
o
H H*1
ow
oII
H.
H, 1 Thermally r
II
II
1
1
r —\
- induced
rzr\ II
1
1
-■o—c-(0)—c —o—c —c- - ----- —►- o—c-(0)—c—o—c —c- - + 'OH

(

HOO
Ọ

Ọ H

II

H-

H

II

I

0 - C - ^ 0 ) - C —O - C — c
'O

I

HJ

•o
Acrylic
acid
— >
Graýt

o

o

H-

H H

II /CT\ II
o -c -(Q )-c -o

i

1
c -c -t
1 1

o

Copolymers

CH
COOH

ồH

AA
—

•
H O -C H ^ C H -C O O H

ĩ

COOH

Homopolymer

T h e w e tta b ility of th e g rafted
sam ple, reílected by g ra ftin g degree,
w as calcu lated a s follows:

ơ (%) = 100 * (W2 ■ vv,) / Wl

(2)

W here: Wj a n d W 2 a re th e
sam p le’s w eig ht m e a su re d b eíore an d
aíler th e graft polym erization, respectively.

i

ọp

c
i
Õ

Fig. 3 show s th e g ra ftin g d eg ree of
th e g ra ft polym erized P E T fìlm su rface
as a fu n ctio n of th e ex p o su re tim e a t
d iííe re n t g ra ftin g te m p e ra tu re s . T he
h ig h est g raftin g d eg ree w as ach iev ed a t
30-sec o f th e ex p o su re tim e. W ith fu rth e r
plasm a irra d ia tio n , th e g ra ítin g d egree
g rad u ally w e n t dow n, th e n leveled OÍT a t

V N U . J o u r n a l o f Scien c e, N a t., Sci.,<í T e c h . 'T J(XJỊỊ, N 0Ị , 2 0 0 7

Exposure time (sec)
Fỉg. 3. Relatỉonship between the grattlng degree
& exposure tỉme o f the PET tilm suríace

52

Nguyen Kicn Cuong

over 90-sec. H ence, th e lo n g er ừ ra d ia tio n tim e th a n 30-sec m ig h t cau se unfav o rab le
etching, cro ss-lin k in g a n d d e g rad a tio n of th e P E T su ría c e , w hich re su lte d in a no n e t
gain of active species on th e irra d ia te d su rface for su b se q u e n t graft-polym erized
process.
A lthough th e p olym erization tim e d im in ish ed to 1 h o u r, th e h ig h e r g raftin g
degree coincident w ith th e h ig h e r a m o u n t of hom opolym ers w as g ained a t g raftin g
te m p e ra tu re of 70°c. T h is can be assig n ed to a larg e n u m b e r of decom posed radicals,
CO* a n d *OH, ow ing to th e th e rm a lly induced d e g ra d a tio n , re a c te d w ith th e AA
m onom er. T he sam e ten d en cy of th e g raftin g degree v e rsu s th e tim e of exposure has
also been rep o rted by Choi et. al. [10].

a)

b)

Fig. 4. Wide-scan spectra o f a) the control surface & b) the suríace irradiated fo r 30-sec,
subsequently gratted at 70°c fo r 1 hour

3.3. ESCA ch a ra cteriza tio n
Surface chemical compbsitions ,%
T he chem ical com positions of th e
P E T film su rface w ere a n aly zed by an Treatment
0 IS/C ls
0 ,s

c,s
ESCA technique. F ig u re 4 show s widescan sp ectra of a) th e con tro l a n d b) th e
Unữeated
73.1
26.9
36.7
9urface irra d ia te d for 30-sec subseGraữed
67.3
32.7
48.6
q u en tly g ra íte d a t 70°c for 1 hour.
P eak s of carbon a n d oxygen b in d in g
en erg ies a re lo cated a t 285 eV an d 532
Table 1. A tom ic com positions on the surface
eV, respectively. I t is n o tew o rth y th a t
irradiated fo r 30-sec and subsequently gratted at
the relative suríace-atom ic concentrations
70°c fo r 1 hour

V N U . J o u rn a l o f S cien c e, N a t.. Sci.,đc T e ch ., T X O l l. N o], 20Ơ


53

Plasm a - Induced graft polym erizalion o f acrylic acỉd onto.

o f oxygen a n d ca rb o n w ere sig n iíìcan tly altered : th e C l s peak of th e g rafted su rface is
lovver th a n th a t of th e control one vvhile O ls peak of th e g rafted su ría c e is little h ig h er
th a n th a t o f th e co n tro l su rface (Fig. 4 & Tab. 1). M oreover, th e
ratio , show n in

ta b le 1, w e n t up from 36.7 % to 48.6 % for th e control a n d g ra fte d suríace, respectively.
F u rth e rm o re th e oxygen c o n ten t rose from 26.9% to 32.7% co rresponding to th e control
a n d g rafted 8urface, respectively. The considerable in c re a se in oxygen atom ics ( 0 lg) is
assig n e d to a larg e a m o u n t of oxygen-containing g ro u p s in co rp o rated onto P E T g rafted
surface. F ig u re 5 show s high resolution scans of th e c u core-level sp ectra for th e
surface, irra d ia te d for 30-sec su b seq u en tly graft-polym erized a t
for 1 h o u r an d the
control one.

70°c

L in e-sh ap e a n a ly s is by th e deconvolution in d ic a te s th a t th e c u sp ectru m of th e
control su ría ce is com posed of th re e d istin c t peak s a t b in d in g energy (BE) of 285.0,
286.5 a n d 289.1 eV, assig n ed to th e
— H,
—
(e.g., e th e r, e ste r) an d 0 —
= 0
(e.g., carboxylic acid, ester) groups, related to an arom atic ring C6H 4—, CH2— CH2 —
o an d CO — o gro u p s, respectively. T hese a ssig n m e n ts a re also in good ag reem en t
w ith th e s tru c tu re of a P E T re p e a tin g unit:

c*

c* o

c*

(— 0 — CO — C6H< — c o — 0 — C H 2— C H 2—)„.
Grafìed surface

o
*
&
g
g
qo

Binding energy (eV)

(a)

(b)

Fig.5. Line-shape & high-resolution analysls o f the C1s peak spectra fo r (a) tha control surface and
(b) tha surtace irradiated fo r 30-sec subsequently gratted at 70°c fo r 1 hour

T h e re la tiv e ch em ical compo- sitions of C i, sp e c tra on th e g ra te d su ríace are
shown in ta b le 2. T h e re is a re lativ e increase in th e c o n te n t of 0 — c* = 0 carboxyỉ
groups from 11.6 to 16.9% a n d th e
= 0 carbonyl group is 9.4 % w hile th e c o n ten t of
c* — H lin k a g e in th e a ro m a tic rin g and c * — 0 g roups decreased from 67.5 to 56.6 %
and from 20.9 to 17.1 %, respectively. T h ese d a ta su g g est th a t th e graftpolym erization m a in ly involves in th e m odiíĩcation of — C6H 4 — a n d — c o — groups.

c*

XNU. J o u rn a l o f S cien c e, N ư ĩ., S ci.,& T e c h ., T.XXỈỊỈ, N 0Ị, 2 0 0 7


54

N guyen Kien Cuon g

M oreover, p o st-p la sm a re a c tio n in a ir of
Decomposition of the c t, peak
free ra d ic als, g e n e ra te d by b roken
c „ component, %
m olecular c h a in s a n d d e h y d ro g e n a tio n
C*-0
0-C*=0
c*=0
Treatment C*-H
m ech an ism s, led to th e íb rm a tio n of
carbonyl fu n c tio n a l g roups: c # = 0 a t
Unừeated
67.5
20.9
11.6
Gratted
56.6
17.1
16.9
9.4
287.9 eV, a new lin k a g e from th e c* — o
group c re a te d by o x id atio n processes.
Table 2. Relative chem ical com positions o f c 1g
C learly, th e P E T su rfa c e w as oxidized
spectra on the surtace ỉrradiated for 30-sec
subsequently gratted at 70°c fo r 1 hour
due to a larg e a m o u n t of oxygenco n ta in in g
íu n c tio n a l

groups
in co rp o rated onto th e P E T film surface. T h e se fu n c tio n a l g ro u p s in crease hydrogen
bonding force a n d th e su rfa c e free en erg y of th e film surface. H ence, hydrophilicity of
th e g ra íte d P E T su rfa c e w as co n sid erab ly en h an ced .

3.4. M orp h ologies o f PET film su rface
F ig u re 6 show s su rfa c e m orphologies of th e co n tro l a n d g ra íte d su ríaces. T he
control su rface (Fig.
6, left) looks like
sm ooth w hile th e
m odiíied one (Fig. 6,
right) seem s to be
rough w ith re g u la r
c o rn -stru c tu re . T h e
m orphological
distin ctio n is
a ttrib u te d to th e
ừ a g m e n ta tio n of
polym er c h a in s
cau sed by th e
surface etch in g , a n d to
Fỉg.6. SEM m ỉcrographs o f the film surtace ỉrradiated for 30-sec
g ra ítin g AA m o n o m er
subsequently gratted at 70°c ío r 1 hour, (lett) the control surtace,
onto th e ra d ica ls, deand (rỉght) the grafted one
com posed from th e
hydroperoxides. I t is a s su m e d t h a t th e ro u g h ed s u ría c e is one of m a in factors th a t
en h an ce h y d ro p h ilic ity of th e P E T surface.

4. C o n c lu sio n s

P la sm a -in d u c e d g ra ft-p o ly m e riz a tio n of acrylic acid onto the poly(ethylene
terephthalate) (PET) íìlm su rfa c e sig n iíìc a n tly im p ro v ed its hydrophilicity. T he PET
surface, irr a d ia te d for 30-sec a n d su b se q u e n tly g ra fte d w ith th e AA m onom er a t 70°c,
show s th e h ig h e s t g ra ftin g d egree. T h e c h a ra c te riz a tio n of th e g ra íte d su rface c le a rlv

V N U . J o u r n a l o f S cien c e. N a i.. S c i,& T e c h .. T XXIỉì. N 0Ì. 2 0 0 7


Plasm a - Induccd graft polym crization o f acrylic acid onto..

55

co níirm ed th e larg e a m o u n t of o x y g en-containing íu n c tio n a l g roups w ere in co rp o rated
o n to th e P E T film in th e form of o — c* = 0 a n d ơ = o , b e in g th e c le a r in d icatio n of
th e h ydrophilic su rface. S h ow n by SEM m icro g rap h s, film su ría c e s, g ra íte d by
copolym ers, show th e ir su rfa ce m orphology like th e re g u la r co rn -su rface t h a t is clear
evidence in m icroporous s tru c tu re . T h is su g g ests t h a t h y d ro p h ilic e n h a n c e m e n t is
closely re la te d to o x y g en -íu n ctio n al g roups in c o rp o ra te d onto th e P E T s u rĩa c e an d its
m icroporous m orphology.

A cknovvledgem ents
T h e re se a rc h w ork w as a p a r t of th e N a tio n a l R e se a rc h P roject, g ra n te d by New
E nergy & D ev elo p m en t O rg a n iz a tio n (N ED O ), a n d c a rrie d o u t a t D e p a rtm e n t of
O rganic M a te ria ls, A dvanced I n s titu te of Science & T echnology (A IST )-K ansai, ơ ap an
(1998-2000). T h e a u th o r g ra te fu lly acknovvledges th e O sa k a S cience & Technology
C e n te r (OSTEC), J a p a n for avvarding th e p o std o cto ral fellow ship a n d re se a rc h g ran t.
S pecial th a n k s a re also due to Dr. S eiichi K atao k a, a íb rm e r s c ie n tis t of th e O rganic
M a te ria ls D e p a rtm e n t, A IS T -K an sai, J a p a n for h is u sefu l d iscu ssio n on th e ex p erim en t
of th e g raft-p o ly m erizatio n . F in a lly , th is w ork did n o t w ell ru n if w ith o u t th e su p p o rt of
Prof. S u su m u Y oshida, fo rm e r D ean of O rg an ic M a te ria ls D ep t., A IS T -K ansai, a t

p resen t, vvorking a t In s titu te of A dvanced E n erg y (IAE), Kyoto U n iv e rsity , J a p a n .

REFERENCES
1.

J.H . Lee, H .w . J u n g , I.K. K ang & H.B. Lee: Cell b e h a v io r on polym er su ría c e s w ith
differen t íu n c tio n a l groups. Biomaterials , 15 (1994) 705-711.

2.

Y. Ikada: S u ría c e m o d iíĩcatio n of polym ers for m edical a p p licatio n s. Biomaterials, 15 (1Ồ94)
725 736.

3.

P.B. VVachem, T. Beugeling, J. Feijen, A. B antjest J. p. Detmers & w . G. van Aken:
In te ra c tio n of c u ltu re d h u m a n en d o th elia l cells w ith polym eric s u ría c e s of different
w ettab ility . Bỉomaterials, 6(1985) 403-408.

4.

c . Wang: Oxidation of polyethylene surface by glow discharge & subsequent graft
copolymerization of acid acrylic. J. Appl. Polym. Sci., Polym. Chem. E d 31 (1993) 1307.

5.

D .s. W avhal & E.R. F ish er: H ydrophilic m odiíĩcation o f p>olyethersulfone m e m b ran es by

low tem perature plasma-induced ^raft polymerization. J. Membr. Sci.t 209 (2002) 255-269.
6.

M. M ori, Y. U y am a & Y. Ik ad a: S u rĩa c e m o dification of p o ly eth y len e fiber by g raft
polym erization. J. polym. Sci.Polym. Chem., 32 (1994) 1683.

7

I.K. K ang, I.K . K ang, O .H . Kwon, Y.M. Lee & Y.K. Sung: P re p a ra tio n & suríace
c h a ra c te riz a tio n of íu n c tio n a l group*grafted a n d h e p arin -im m o b ilizeđ p o ly u reth an es by
p la sm a glow d isch arg e. Bỉomaterials , 17 (1996) 841*847.

8

N.K. Cuong, N. Saeki, s. Kataoka & s. Yoshikawa: Hydrophilic improvement of PET fíber
using plasma-induced graft polymerization at atmospheric pressure. Hyomen Kagaku,
ơournal o fS u rfa c e Science Society, Japan> Vol. 23, No. 4 (2002) 202-208.

vvơ. J o u r n a l o f S c ie n c e .

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N guyen Kien Cu ong’.

56

9.

H . Y a s u d a : P la s m a Polymerization. A c a d e m ic P r e s s , N e w Y o rk , 1985.

10.

H.s. Choi, Y.s. Kim, Y. Zhang, s, Tang, s.w. Myung & B.c. Shin; Plasma-induced graft
copolymerization of acrylic acid onto the polyurethane suríace. Surface & Coating
Technology>182 (2004) 55-64.

TẠP CHÍ KHOA HỌC DHQGHN. KHTN & CN, T.XX1IỈ, Số 1, 2007

TRÙNG HỢP & CẤY GHÉP AXÍT ACRYLIC VÀO BỂ MẶT PHIM
POLY(ETHYLENE TEREPHTHALATE) BANG PLASMA: b i ế n t í n h
THẤM ƯỚT
Nguyễn Kiên Cường
Khoa Hóa học, Đại học Khoa học Tự Nhiên, ĐHQGHN
Biến tín h th â m ướt của p o ly(ethyleneterephthalate) (PE T) phim , ổn đ ịn h th eo thòi
gian, có th ể được th ự c h iệ n b ằn g phư ơng p h áp chiếu xạ k h í ag o n -p lasm a, v à trù n g hợp
ghép vói hơi a x ít acrylic (AA). c ả h a i phư ơng p háp chiếu xạ p la sm a và tr ù n g hợp ghép
AA m onom e đều tă n g k h ả n ă n g th ấ m ưốt củ a bề m ặ t P E T phim . T uy n h iê n n ếu xử lý
bể m ặ t P E T b ằ n g các phương p h áp trê n n h ư n g riê n g rẽ, th i tín h th ấ m ư ót của P E T
phim bị suy giảm th eo thời gian. T ro ng k h i đó k ế t hợp cả h a i phương p h á p xử lý trê n sẽ
cho phép P E T phim duy trì tín h th ấ m ướt th eo thời gian. K ết q ủ a n g h iên cứ u đã chỉ ra
rằ n g sự p h â n rả của các chuỗi p h â n tử lớp bể m ặ t polym e tỷ lệ th u ậ n vối thời gian
chiếu xạ. P hổ ESCA đã cho th â y sự g h ép -trù n g hợp c ủ a AA m onom e đ ã cho m ột sô'
lượng lớn các nhóm chức như: (0
= 0 ) carboxylic
(C* = O) carbonyl, được cấy
ghép vào bể m ặ t P E T phim . H ìn h th á i bề m ặ t của bề m ặ t P E T phim được xử lý là m àng
copolyme có độ dày vài tră m n an o m ét, có đặc tín h th ấ m ướt, có cấu trú c lỗ xốp và liên
k ế t hoá học với lốp P E T n ền . Đ iều đó có th ể q u a n s á t b ằ n g k ín h h iển vi đ iện tử q u ét
(SEM). G h é p -trù n g hợp các nhóm chức và cấu trú c lỗ xốp của bề m ặ t p h im sau k h i xử
lý là n h ữ n g n h â n tố ch ín h để tă n g k h ả n ă n g th ấ m ướt c ủ a P E T phim .

—c*

&

T ừ k h o á : T rừ n g hợp ghép b ằ n g chiếu xạ p la sm a , đ ứ t m ạch chuỗi polym e, nhóm
chức, tín h th ấ m ướt, vi lỗ & p h ổ tia X cho p h â n tích hoá học (ESCA).

V N U . J o u n i a l o f S c ie n c e . N a i.. S c i . i T e c h .. T.XXIII. N 0I, 2 0 0 :