Chemistry Reference
In-Depth Information
O
H
O
10 mol% A IBN,
70 °C, 8 h
10 eq. RSH
O
H
O
S
R
H
2
O
2
,30%
8h,reflux
O
H
O
S
O
R
O
acid cata lyst
R'OH
O
R'
O
S
O
R
O
Scheme 4.9 The synthesis of sulfone derivatives of oleic acid. R
¼
ethyl, butyl or
hexyl, R
0
¼
methyl or butyl.
40
because of the unpleasant odor of the products and their decomposition
products. The sulfoxides decomposed above 135 1C, whereas the sulfones
were thermally stable to 250 1C.
Six of the bio-based sulfones synthesized and two commercial plasticizers
were compared as plasticizers in a PVC composition containing 100 parts by
weight PVC, 50 parts plasticizer, 3 parts ESBO as a co-stabilizer, and 2 parts
Ca/Zn-base stabilizer. The glass transition temperature (T
g
) of the sulfones
was between
9.6 and
30.0 1C, which was higher than
33.6 and
43.6 1C
for the commercial plasticizers. The volatility of the sulfones after 4 min at
200 1C was comparable to the volatility of one commercial plasticizer and
higher than other commercial plasticizers. The worst volatility was observed
for the product from canola oleic acid. The authors attributed the high
volatility to the presence of sulfones from linoleic acid, which they thought
were less stable thermally. The complex viscosity at 25 1C, which is preferred
to be low, was about an order of magnitude higher than the complex
viscosity of the composition with commercial plasticizers. The PVC formu-
lations with sulfones had reduced gelation temperatures, compared to the
commercial formulations, indicating that the bio-based formulations could
be easier to process. The thermal stability of the bio-based formulations at
200 1C was lower than that of the commercial additives; the PVC darkened
due to the release of hydrochloride from the backbone within 4-5 min for
the formulation with sulfones, while the formulations with the commercial
plasticizers darkened after 7 min. The Shore hardness was
10% lower for
the bio-based sulfones, thus showing better effectiveness in plasticizing the
polymer. The bio-based plasticizers induced higher water uptake and higher
plasticizer losses after drying.
B
