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SYNTHESIS AND CHARACTERIZATION OF MULTI-HOLLOW OPAQUE
POLYMER PIGMENTS








A THESIS SUBMITTED TO
THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES

OF
MIDDLE EAST TECHNICAL UNIVERSITY








BY


SERDAR ASMAOĞLU







IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR

THE DEGREE OF MASTER OF SCIENCE
IN

CHEMICAL ENGINEERING







JULY 2012

Page 67

47

are shown in Figure 3.9 and Figure 3.10, respectively. Briefly, monomer

mixture of 5 g MMA and 5 g EGDMA was prepared first by magnetic stirring

at 400 rpm for 15 minutes in a 25 ml erlenmeyer flask. Oil soluble free

radical initiator (AIBN) was added to monomer mixture and dissolved with

further mixing of 15 minutes. Then, surfactant mixture of Span 80 and

Tween 80 were added to prepared monomer mixture and dispersed for 30

minutes at 400 rpm by magnetic stirrer. The ratio of the binary mixture of

span 80 and Tween 80 mixture was estimated according to Hydrophilic-

Lipophilic Balance value concept. HLB value of surfactant mixture was

calculated by using Equation 3.1 [20, 21].



mix 1 1 2 2

mix

1

2

HLB =x HLB +x HLB

where; HLB : HLB value of surfactant mixture.

x : weight fraction of surfactant 1.

x : weight fraction of surfactant 2.


1

2

HLB : HLB value of surfactant 1.

HLB : HLB value of surfactant 2.

(3.1)

The HLB values of surfactant mixture were fixed at 5, 6, 7, 8 and 9. The

ratios of binary surfactant mixtures are given in Table 3.6.





Table 3.6 Surfactant ratios at given HLB values.

Surfactant composition/HLB
value

HLB 5 HLB 6 HLB 7 HLB 8 HLB 9

Span 80 : Tween 80 (%w/w) 93:7 84:16 75:25 65:35 56:44

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