Surface modification of MgO filler by radiation

Rodiot. Printed

Phys. Chem. Vol. in Great Britain

42, Nos

l-3,

pp. 77-80,

0146-5724/93

1993

Pergamon

$6.00

+ 0.00

Press

Ltd

SURFACEMODIFICATIONOF NgO FILLER BY RADIATION

Feng Yuding, (Department

Huang Guanglin,Gan

of ChemistryrSichuan

Chonglin,

Chen Zefang

Universityr610084,P.R.China)

Abstract Direct radiation method has been used to graft methyl methaorylateMlA) onto magnesium oxide(Ng0) powder. surface The graft products were oharacterized by FT-IRS X-ray diffraction. Their properties were studied by ESCAI SEH and &termination of water contact angle. The grafted RgO was used as a filler of HDPE. The experimental results showed that the dispersibility of MgO in polymer matrix is remarkably improved, when the NgO is grafted with MA. The tensile strength and elongation percentage at break of HDPE filled the modified MgO were higher than those of unmodified. When the HDPE was filled by modified MgO, its thermal stability was remarkably improved.

Keywords:

Ragnesium oxides

Filler.

Radiation

grafting,

Surface

modification.

Magnesium oxide #gOI is one of the important fillers used in polymer materials. Low molecular weight coupling agenttsuch as titanate* aluminate, phosphate etc.) is always used to improve the compatibility between filler and polymer matrixt but it is easily fallen from filler during processing, because the coupling-bridge between polymer and filler is not covalent bond. In resent years* using grafting method to modify the (R.Laible. 1980). Because grafted polymer chain surfaoe duing prooessingr thus the properties of studies on surface modification of carbon black by 1990; N.Tsubokawa) .

surface properties of filler is developed can not fall from inorganic mater ial complex materials can be improved. Some chemical grafting were reported(K.Fujiki.

In the present paper* direct radiation method has been used to graft MA onto MgO powder filler. The properties of grafted MgO were studied. Further more? the effects of grafted Kg0 on the properties of HDPE were discussed.

Experimental 1. Grafting procedure and characterization of grafted copolymer: The RgO with MMAand solvent were irradiated at room temperature in air by 1.5 t4eV electron beams from a JJ-2 type accelerator. After irradidtionp the products were extracted with benzene for 24 hours in order to remove off ungrafted PNRA homopolymer. The weight increasing over k0 was characterized by FT-IRI X-ray diffractions SE% element analysis and water contact angle &termina,tion. 2. Blending with HDPE and the &termination of properties of filled HDPE: Blend grafted RgO with HDPE at ratio of 10: 90~ then press it to plate under 17

oil-compressor.

78

FENG

Determine

its

properties

Results 1.

1.

showed

results

obtained

method

coincided

DTA and

tension

of that

grafted

the

yield

increasing

with

each

other

Table

1.

Graft

Weight

was

increased

is

with

the

e I emcnt

method,

increasing

analysis

yield

of

MgO at

increeasing

different

Element

analysts

Thermal

method(%)

5.04

7.72

7.18

7.80

6

10.02

9.52

9.87

8

11.97

10.13

12.05

10

12.14

11.41

12.10

of

MgO and MgO-g-PMMA.

spectra

related

C=O vibration

to

C-H

vibration

The

gravity

gravity

5.43

FT-IR

dose.

thermal

method(%)

4

the

irradiated and

doses

2

1700cm’-’

of

method

reliably.

method(I)

Fig.1

tester.

copolymer:

graft

by weight

doses(Mradr

and

et al.

and Discussion

Characterization

Table

by SEM,

YUDING

peak.

5.21

It

800-1400cm-’ can

related

be known

that

to

MMA has

been

peak,

grafted

onto

MgO powder.

F-Fig.1.

FT-IR

spectra

grafted

of

MgO and

20'

Fig.2.

X-ray

MgO.

of

structure

influence chain peak 2.

of

into at

7’

Surface

Fig.3.

indicated

properties the

but

MgO was determined

grafted

structure

on crystal

MgO crystalpits

showed

much looset

of

grafting

surface

that

the

of

grafted

grafting.

of

by

of

X-ray

the

grafting

schame MgO

diffraction

samll

because

amorphous

(Fig. of

2)~

insertion

peaks

and

there of

the

is

less

grafting

non-crystal

chain.

copolymer: of the

MgO and grafted apparentness

of

MgO. The MgO became

apparentness compact.

b.

a. Fig.3.

65

diffraction

MgO and grafted

MgO. However,

was damaged,

existence

SEM photographs

after

50”

(a-MgO; b-MgO-g-PM?4A)

(a-MgO; b-MgO-g-PMMA) Crystal

35”

SEM photographs

of

MgO and grafted

(a-MgO;b-MgO-g-PMMA)

MgO.(XSOOO)

of

ungrafted

MgO was

8th International

Fig.

4a-4b

were

binding

energy

more

shifting

the

level.

It

Cl., of

01. Cl.

ESCA spectra is

shifted

extent.

was supposed

Howevert that

of

to

Meeting

on Radiation

grafted

copolymerr

lower

the

energy

binding

energy

of

C=O was formed

covalent

respectively.

p and

level

19

Processing

the

01.

were

between

It

higher

the

the

can

be

graft

shifted

to

lattice

0

seen

yield

that

is.

higher

the

energy

in HgO and

B-C

in

=H, HHA. i.e.*

Ch arge

(MgO),-(Ctls-6-L

cloud

of

lattice

0 biased

to

CI

and

charge

that

made the

charge

density

cOOLtij of

C increased.

binding

The

ratio

of

so

energy

of

0 to

graft

yield,

Fig.4a.

Ct.

its

binding

energy

decreased.

C was determined the

O/C

Binding

by ESCA.

water

increasing

contact

modificationpthe it

can

angle

of

grafted

2.

that

listed

Relationship

the

of

01.

in Table

of

0 decreased.

its

2.

With

the

increaing

EnergyCev)

ESCA spectra

O/C with

graft

graft

yield(Z)

o/c

1

3.

397

3.

358

7.72

3

2.

243

11.97

MgO plate

yield,

Fig.4b.

UgO

2

the

hydrophilicity

predict

were

Bindins

of

of

graft

Results

(eV)

Energv

ESCA spectra

sample

the

density

decreased.

Table

The

the

increased.

of

before

contact

angle

t4gO decreased9

compatibility

of

grafted

MgO

yield

5.43

was determined water

of

and

grafted

and after

became

the

grafting

hydrophobicity

MgO with

(Table

much bigger.

organic

That

increased.

polymer

3). is,

From

materials

With after theset

must

be

increased. Table

3.

Determination

of

samp I e

water

graft

yield(X)

1

The effects

Fig.5. matrix* well,

of

showed the

modified

unmodified

i.e.rits

(a--filled

with

yield(Z)

Spread

2

3.

356

7.72

2.

243

11.97

of

with

properties

unmodified

polymer

of

MgO

out

HDPE:

and modified

appeared

modified

5.43

obviously,

matrix

is

a Fig.S.SEH

graft

3

higO particals

compatibility

of

397

3.

MgO on the

SEM photographs

angle

0

W

3.

contact

MgO with

HDPE.

however*

modified

We can

much better.

b photographs 107, MgO;

of b--filled

HDPE filled with

with

MgO.(XSOOO,

107, G%=7.727.

modified

&O)

MgO

see

thattin

dispersed

HDPE very

80

FENG YUDING

et al.

Table 4. showed the effects of modified and unmodified HgO on break elongation percentage and break strength of BDPE. It can be seen that the elongation decreased with the adding of filler. But the elongation percentage of HDPE with modified BgO is higher than that with unmodified )IgOr beoause of the increasing of oompatibility. And the break strength is the same tendency. Table 4. The effects Sample

of modified

Break strength(N/sm?)

Pure HDPE

MgO on mechantical Break elongation

properties percentage(X)

25.6

800

HDPE filled

10X m-I&O 18.2

600

HDPE filled

10X u-k&l

450

12.7

of HDPE.

Fig. 6-7 showed the DTA and TCA picture of HDPE and blend of HDPE with modified adding of modified RgO, the thermal stability of HDPE was increased. The melting 25“ Grand the maximum weight-loss temparature increased 40” C. loo 83 60

1

40 x 0L 0 1mmmmsa3 T ( “C.1

Y-+= lal

Fig.6. The TCA schame of HDPE. (a-pure HDPE;b-HDPE filled 10X G%=7.72% m-MgO)

M) -

Fig.7. The DTA schame of HDPE. (a-pure HDPE:b-HDPE filled 1071 Ci%=7.72%m-t4gO)

References Adv.Colloid Interface 5ci.t 1. R. Laib1e.t Po1ym.J.t 22(8),661(1990). 2. K. Fujiki., 3. N. Tsubokawa.r Po1ym.J.e 22(93.827(1690).

2co T( T 1

600

13,65(1680).

MgO. With the point arised