Coatings / Paints / Additives / Adhesives VeoVa Monomers Characteristics and Reactivity Parameters

Product Bulletin
Coatings / Paints / Additives / Adhesives
VeoVa™ Monomers
Characteristics and Reactivity Parameters
VeoVa 9 monomer and VeoVa 10
monomer represent a family of vinyl
ester monomers with a unique, high-
VeoVa 9 and 10 are monomers with
many similarities. Their main
characteristics are as follows:
■
ly branched, carbon-rich structure.
Their principal use is as modifying
comonomers in vinyl and acrylic
polymerisation. Typical properties
and specifications are listed in their
respective product data sheets.
■
A branched tertiary structure with
bulky and hydrophobic hydrocarbon
groups. This provides the monomers
with a very low surface tension and
a hydrophobic nature. As a consequence, the monomers possess a
strong resistance to saponification.
Furthermore, VeoVa monomers do
not degrade under the influence of UV
light.
Reactivity: VeoVa monomers polymerise with various other comonomers through reaction of their vinyl
ester functional group. In this way,
the specific properties of the VeoVa
monomers can be imparted to their
copolymers.
CH 3
O
C
CH 2
CH
O
C
R1
R2
Structure of VeoVa monomers where R1 and R2 are
(branched) alkyl groups containing 6 or 7 carbon
atoms for VeoVa 9 and 10 monomers respectively.
Vinyl Ester
Structure and Properties:
Similar reactivity to vinyl acetate producing random copolymers
■
■
Easily copolymerisable with ethylene,
acrylates and methacrylates
Versatic Acid 9 and 10
Structure and Properties:
Hydrophobic
■
■
UV resistant
■
Hydrolytically stable
■
Non-hazardous
Protection of vinyl acetate
against hydrolysis by adjacent
VeoVa monomer groups
H2O
OH
H2O
OH
H2O
H2O
H2O
OH
OH
O
O
O
O
O
O
O
O
O
O
O
O
Polymer chain
Protected
vinyl acetate
The various VeoVa monomers mainly
differ in the degree of branching and the
length of the hydrocarbon groups. This
leads to differences in the glass transition temperature of their homopolymers,
and consequently to a different behaviour as modifying comonomers. Whereas VeoVa 9 monomer provides rigidity
to the copolymer, VeoVa 10 monomer is
known as a flexibilising comonomer.
Reactivity of VeoVa monomers
VeoVa monomers can be used with a
variety of other monomer types to produce copolymers. The ease of polymerisation depends on the reactivity ratios of
VeoVa monomer
Tg of homopolymers
Monomer
Tg [ °C ]
VeoVa 9
+ 70
VeoVa 10
-3
the monomers used. VeoVa monomers
copolymerise very easily with other
vinyl esters, ethylene and most acrylic
monomers.
Reactivity ratios of vinyl ester monomers with other monomer types
Monomer 2
Temp. [ °C ]
r1
r2
Source
Styrene
VeoVa 10
VeoVa 10
140
170
25
23
0.04
0.06
2
2
2-Ethylhexylmethacrylate
VeoVa 10
VeoVa 10
140
170
10.5
3.6
0.08
0.06
2
2
Monomer 1
Methyl Methacrylate
Vinyl Acetate
60
20
0.015
1
Ethyl Acrylate
VeoVa 9
60
6
0.10
2
Butyl Acrylate
Vinyl Acetate
-
5.89
0.05
1
Vinyl Acetate
VeoVa 10
VeoVa 9
Ethylene
60
60
130
0.99
0.93
1.02
0.92
0.90
0.97
1
1
1
1
Young, Polymer handbook, Chapter II, J. Brandrub, E.H. Immergut
and W. McDowell, Eds., Wiley-Interscience, New York, 1975
2 Laboratory measurements
Reactivity of VeoVa monomers
with vinyl acetate
VeoVa monomers are commonly used
as comonomers for vinyl acetate in
emulsion polymerisation because they
exhibit a similar reactivity. During emulsion or solution polymerisation, VeoVa
monomer and vinyl acetate are converted at the same rate. They can be copolymerised in any desired ratio, producing
polymers with a random microstructure.
This allows the key performance characteristics of VeoVa monomers to be
fully exploited. Commonly used emulsion polymerisation tempera­tures are in
the range of 76 – 80 °C, with potassium
persulphate as initiator.
Vinyl acetate and VeoVa 10 instantaneous monomer conversion determined by
Gas Chromatography during a semi-continuous emulsion polymerisation process
Instantaneous conversion [ % ]
100
80
60
Start
monomer addition
End
monomer addition
Post cooling allows reducing
the residual monomer content
down to < 100 ppm levels
40
20
0
50
100
150
200
250
300
350
400
Time [ min ]
VeoVa 10
Vinyl acetate
Reactivity of VeoVa monomers
with (meth)acrylates
VeoVa monomers can be polymerised
with acrylate and methacrylate monomers in emulsion, in solution or in bulk.
Optimum results are generally obtained
by using a semi-continuous process.
This results in better control of the reactor temperature and in polymers with a
more random microstructure.
For emulsion polymerisation, a slightly
higher reaction temperature of 85 °C is
recommended to achieve a more random polymer structure. For solution or
bulk polymerisation, the best results are
obtained at 140 °C and above.
Reactivity of VeoVa monomers
with styrene
VeoVa monomers do not polymerise
with styrene in emulsions. Higher
temperatures are required to achieve
good control over the reaction, and
acrylate monomers should be present
to bridge the reactivity differences.
Suitable recipes for solution and mass
polymerisation at temperatures around
160 °C are described in separate bulletins.
Handling precautions
For more detailed information on all
aspects of Health, Safety and Handling,
please reference the Safety Data Sheets
of VeoVa monomers, which are available
from your local Momentive representative or distributor. The precautions
advised therein should be strictly observed. For details related to other products listed in this bulletin, please contact
the suppliers of those products.
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