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PREPARATION OF POLYSTYRENE WITH HIGHER Tg BASED ON
TRIPLE HYDROGEN BOND INTERACTION
MBULU AGALIA
MATERIALS SCIENCE
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Contents
Abstract...............................................................
......... .........2
Abstract in Chinese ...
................................................................4
Chapter 1 Introduction................ ...................
......5
1.1 Glass transition
temperature.............................................................5
1.2
Styrene and Maleimide
copolymer....................................................14
1.3 Melamine and chemistry
.............................................................23
1.4 Diaminopyridine
molecule..............................................................26
1.5 the thesis
work...........................................................................27
Chapter 2 Experimentation
Section.............................................31
2.1
Materials.................................................................................31
2.2
Instruments..............................................................................31
2.3 Synthesis of random copolymers of styrene and
maleimide......................32
2.4 Synthesis of Blends of Styrene/Maleimide copolymer and
melamine...........32
2.5 Synthesis of Blends of the copolymer and
2,6-diaminopyridine.................33
Chapter 3 Results and
discussion................................................34
3.1 Characterization of copolymer of styrene and
maleimide..........................34
3.2 Copolymerization of styrene and
maleimide........................................33
3.3 Blends of the styrene/maleimide copolymers and
melamine............................38
3.4 Blends of the copolymer and
2,6-diaminopyridine..................................43
Chapter 4
Conclusion.................................................................46
Reference...................................................................................47
PREPARATION OF POLYSTYRENE WITH HIGHER Tg BASED ON
HYDROGEN BOND INTERACTION
ABSTRACT
Polystyrene is one of a common polymer. But its glass
transition temperature (Tg) is only 100oC which leads to limit its
applications. In the thesis, improvement of its Tg was done via increase of its
chain interactions to restrict the chain flexibility.
Styrene was copolymerized with maleimide, imide of which act
as a hydrogen-bond interaction site in the copolymer, by free radical
polymerization method in DMSO solution at different temperature, and
different ratio of styrene to maleimide, and different reaction time, using
different amount of AIBN as an initiator. To make the imide distribute
randomly in the chains, maleimide was dropped slowly during the
polymerization. Melamine and diaminopyridine were selected to be as interaction
molecule because they can form the triple hydrogen bond with imide in the
copolymer. Addition of melamine or diaminopyridine into the copolymer results
in a dramatic increase of Tg. Polystyrene with imide molar concentration of
5.05% has Tg of 122oC in the presence of melamine, 22 oC
higher than polystyrene, which will extend application of polystyrene. At high
ratio of melamine to imide, two Tgs are observed, one is higher than
122oC but another much lower. The existence of two Tg is due to the
fact that free melamine is acting as plasticizer.
Diaminopyridine also increase Tg of polystyrene, but not
effectively than melamine owing to lack of crosslinking. In this case, the
blend of Diaminopyridine with polystyrene containing imide looks like a
copolymer of styrene with a big monomer, complex of maleimide and
Diaminopyridine.
The secondary interaction characteristics between melamine or
Diaminopyridine with polystyrene containing imide is confirmed by their blends
readily soluble in DMSO and in CH2Cl2.
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