STRUCTURE AND MORPHOLOGY OF SEMI CRYSTALLINE LDPE NANO-

POLYMER

Khalefa Al Zenidy

Under supervision ofAssoc. Prof. Dr. M. S. Gaafar

OUTLINES

Abstract. Experimental setup. Results. Conclusion.

ABSTRACT

Low density polyethylene (LDPE) nano-polymers were subjected to a high power ultrasonic irradiation as a polymerization initiator, at different times (0, 5, 10 and 15 minutes). Characterization was performed on the non-irradiated and irradiated LDPE samples by recording the XRD patterns and measuring the low power ultrasonic wave velocities (Longitudinal and Shear) together with density measurements.

EXPERIMENTAL SETUP

RESULTS

5 10 15 20 25 30

0 m

in

5 m

in

10

min

15

min

2 Theta [ ]

Inte

nsi

ty [

A.U

]

(110)

(200)

Fig. 2, X-ray diffraction patterns for LDPE samples at different irradiation times.

RESULTS

0 5 10 157.50

7.52

7.54

7.56

a b

Ultrasonic irradiation time [min]

a, [Å

]

4.98

5.00

5.02

b, [Å

]

Fig. 3, Variation of lattice constants (a & b) for LDPE samples at different irradiation times.

RESULTS

0 5 10 15135

140

145

150

155

L D

Ultrasonic Irradiation time [min]

Cry

stal

lite

size

, L [Å

]

5.180

5.185

5.190

5.195

5.200

5.205

5.210

5.215

5.220

5.225

5.230

Inte

rcha

in d

ista

nce,

D [Å

]

Fig. 4, Variation of the crystallite size and inter-chain distance for LDPE samples at different irradiation times.

RESULTS

Fig. 5, Variation of both (longitudinal and shear) ultrasonic velocities for LDPE samples at different irradiation times.

0 5 10 15

1300

1400

1500

1600

Ul Us

Ultrasonic irradiation time [min]

Long

itudi

nal u

ltras

onic

wav

e ve

loci

ty, U

l [m

/s]

600

650

700

750

800

She

ar U

ltras

onic

wav

e ve

loci

ty, U

s [m

/s]

RESULTS

Fig. 6, Plot of the ultrasonic absorption coefficient and ultrasonic viscosity for LDPE samples at different irradiation

times.

0 5 10 151.2

1.3

1.4

1.5

1.6

us

Ultrasonic irradiation time [min]

Ultr

ason

ic a

bsor

ptio

n co

effic

ient

, [

dB/c

m]

16

18

20

22

24

26

28

30

32

34

36

38

40

42

44

Ultr

ason

ic v

isco

sity

, us

[mP

a.s]

RESULTS

Fig. 7. Dependence of Poisson's ratio and cross-link density for LDPE samples at different irradiation times.

0 5 10 15

0.325

0.330

0.335

0.340

0.345

0.350

Nc

Ultrasonic irradiation time [min]

Po

isso

n's

rat

io,

0.40

0.42

0.44

0.46

0.48

0.50

0.52

0.54

0.56

Cro

ss-l

ink

den

sity

, Nc

CONCLUSION

This research study showed the effect of the high power ultrasound to initiate the polymerization of LDPE in the nano-size. The results predicted the effect of ultrasound on the structure of these polymer samples. Also, the results of XRD and ultrasonic wave velocities were found to be in good agreement with each other.

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