veova™ monomers characteristics and reactivity parameters
TRANSCRIPT
Product Bulletin
VeoVa™ MonomersCharacteristics and Reactivity Parameters
VeoVa 9 monomer and VeoVa 10
monomer represent a family of vinyl
ester mono mers with a unique, high-
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.
VeoVa 9 and 10 are monomers with many similarities. Their main characteristics are as follows:
■ 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 conse-quence, the monomers possess a strong resistance to saponification. Furthermore, VeoVa monomers do not degrade under the influence of UV light.
■ Reactivity: VeoVa monomers poly-merise with various other comono-mers through reaction of their vinyl ester functional group. In this way, the specific properties of the VeoVa monomers can be imparted to their copolymers.
Coatings / Paints / Additives / Adhesives
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.
CHCH2
CH3
R2
R1CCO
O
Vinyl Ester
Structure and Properties: ■ Similar reactivity to vinyl acetate produc-ing random copolymers
■ Easily copolymerisable with ethylene, acrylates and methacrylates
Versatic Acid 9 and 10
Structure and Properties: ■ Hydrophobic ■ UV resistant ■ Hydrolytically stable ■ Non-hazardous
Reactivity of VeoVa monomers VeoVa monomers can be used with a variety of other monomer types to pro-duce copolymers. The ease of polymeri-sation depends on the reactivity ratios of
the monomers used. VeoVa monomers copolymerise very easily with other vinyl esters, ethylene and most acrylic monomers.
Protection of vinyl acetate against hydrolysis by adjacent VeoVa monomer groups
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 transi-tion temperature of their homopolymers, and consequently to a different behav-iour as modifying comonomers. Where-as VeoVa 9 monomer provides rigidity to the copolymer, VeoVa 10 monomer is known as a flexibilising comonomer.
Tg of homopolymers
Monomer Tg [ °C ]
VeoVa 9 + 70
VeoVa 10 - 3
Reactivity ratios of vinyl ester monomers with other monomer types
Monomer 1 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
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
O O O O O O O O O O O O
OH
H O2
H O2
H O2
H O2
H O2
OHOH
OH
Polymer chain
Protectedvinyl acetate
VeoVa monomer
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 emul-sion or solution polymerisation, VeoVa monomer and vinyl acetate are convert-ed at the same rate. They can be copo-lymerised in any desired ratio, producing
polymers with a random microstructure. This allows the key performance char-acteristics of VeoVa monomers to be fully exploited. Commonly used emul-sion polymerisation tempera tures are in the range of 76 – 80 °C, with potassium persulphate as initiator.
Reactivity of VeoVa monomers with (meth)acrylates
VeoVa monomers can be polymerised with acrylate and methacrylate mono-mers 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 reac-tor 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 ran-dom 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 bul-letins.
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 represen-tative or distributor. The precautions
advised therein should be strictly ob-served. For details related to other prod-ucts listed in this bulletin, please contact the suppliers of those products.
100
0
Inst
anta
neou
s co
nver
sion
[ %
]
Time [ min ]
10050 150 200 400
80
Vinyl acetate and VeoVa 10 instantaneous monomer conversion determined byGas Chromatography during a semi-continuous emulsion polymerisation process
60
40
20
Startmonomer addition
Endmonomer addition
250 300 350
Post cooling allows reducingthe residual monomer contentdown to < 100 ppm levels
VeoVa 10 Vinyl acetate
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