Chemistry Reference
In-Depth Information
Moulding release agents will require to be inert to the curing reaction, low
cost and able to be applied without major diculties, furthermore they should
not produce uneven colouring on the concrete surface.
The concrete industry has traditionally employed large tonnages of mineral-
based emulsions as release agents primarily derived from the motor industry;
however, directives make the use of sustainable moulding agents compulsory.
By using vegetable oil derived products this industry may overcome the current
challenges it faces.
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6.5.4.3 Cutting Metal Fluids
UCO has been tested as a suitable raw material for conversion into
metal working fluids, as a renewable-based alternative to petrochemical
sources. Liquid lubricants are constituted by base oil (main component)
and a number of other additives with different functionality (antiwearing,
stabilisers, antioxidants, detergents,
etc.),
changing depending on the
application.
The use of triglycerides in lubrication and cutting working fluids might be
done by using the net triglyceride or through chemical modifications such as
partial conversion into soap, amides or transesterification into alkyl ester to
improve/ modify the properties of the formulation (i.e. performance, partial
emulsification of water in cutting fluids, etc.).
High oleic sunflower oil-UCO (HOSO) (iodine value 75-95) is a vegetable oil
with a large number of technical applications due to its good behaviour of
oxidation and thermal stability plus adequate viscosity and high-temperature
performances, which makes it a good candidate to become the base oil (main
component of a lubricant) for a bio-lubricant either net or as a blend with
conventional mineral-based oils.
6.5.4.4 Cosmetic, Paints and Varnishes
UCOs have also been proposed for the production of bioderived coatings,
paints and varnishes. These industries are moving towards safer (i.e.
nonflammable, non-VOC containing) alternatives as the mineral base of these
products is a large source of contaminants. Most varnishes are a blend of resin,
drying oil and volatile solvent, from which alkyds are the most important class
of resin in the coatings industry.
Alkyds are made of an alcohol such as glycerol, a dibasic acid and oils
including castor, coconut, linseed or soybean. Vegetable oils with a high level of
unsaturated fatty acids have been tested as varnish agents (i.e. linseed, soy
bean, high linoleum sunflower and castor oil), by chemical transformations
under controlled mechanisms of polymerisation.
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Condensation with polyols
for the formation of alkyd resins, radical polymerisation and oxidation
are required to form a solid polymerised matrix from UCOs. The main
challenge with the use of these types of UCOs within these applications is
their relatively short shelf-life and poor oxidative stability. Oils degrade
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