8 Oleochemistry Products
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8.5.4 Why Bio-plasticizers
As argued before, the application of phthalates is nowadays an object of debate by
the international scientific community due to their toxicity issues arising from their
aptitude to migration. DEHP is listed among potential carcinogenic substances, thus
it has been banned in specific uses, like toys and healthcare supplies. For others, there
are severe restrictions in some Countries concerning their concentration in childcare
material. Therefore, it results imperative to find a valid alternative, characterized by
low toxicity and limited migration.
The ideal bio-based plasticizer must lower the T g value of polymers, be
biodegradable, no toxic, no volatile and must have the minimal aptitude to migration.
Bio-plasticizers, owing to their biological nature as they are obtained from agricultural resources, seem to rise to the challenge. Many plasticizers come from different
renewable and biological sources, such as cereals or oleaginous plants, or a waste of
agricultural industries (Reports 2017).
Starches and cellulose, extracted from rice, potatoes and straw fibres, are natural
sources for bio-based plasticizers. Sugar derivatives, such as sugar alcohols and
isosorbide esters, obtained by chemical modification of glucose or mannose, are
suitable renewable plasticizers. Sugar alcohols are polyols used for the plasticization
of starch, in mixture with glycerol. Isosorbide esters, obtained by double esterification
of isosorbide and long-chain acids, are effective plasticizers of PVC due to their
structure, similar to phthalates.
From citrus fruits and sugarcane, citrate-based plasticizers are obtained. These
esters of citric acid are used as plasticizers of PVC, cellulose and PLA.
Glycerol, the main by-product of biodiesel synthesis, is well known to be a suitable
plasticizer for starch thanks to the presence of three hydroxyl groups.
Recently, cardanol and its derivatives have been reported as precursors of bioplasticizers. The chemical structure of cardanol is quite similar to one of the most
famous phthalates like DEHP. For this reason, it shows good miscibility with PVC
and it can be used as a secondary plasticizer.
Bio-plasticizers can be also found out by natural wastes, such as tannins or derivatives of tannic acid for cement and sugar bagasse for cellulose acetate. Also, liquefied
wood esters have shown good plasticizing properties.
Another important aspect that spurs the bio-plasticizers market concerns recent
advances on bio-based plastics due to petroleum-raw resource depletion. As
the demand for bio-plastics continuously grows, also the demand for new bioplasticizers, with new properties and performances, and compatible additives grow
in parallel. The principal biodegradable polymers are synthesized from biomass like
agro-resources or obtained by microbial fermentation, such as PLA, PHA, PBSA,
PHBv.
249
8.5.4 Why Bio-plasticizers
As argued before, the application of phthalates is nowadays an object of debate by
the international scientific community due to their toxicity issues arising from their
aptitude to migration. DEHP is listed among potential carcinogenic substances, thus
it has been banned in specific uses, like toys and healthcare supplies. For others, there
are severe restrictions in some Countries concerning their concentration in childcare
material. Therefore, it results imperative to find a valid alternative, characterized by
low toxicity and limited migration.
The ideal bio-based plasticizer must lower the T g value of polymers, be
biodegradable, no toxic, no volatile and must have the minimal aptitude to migration.
Bio-plasticizers, owing to their biological nature as they are obtained from agricultural resources, seem to rise to the challenge. Many plasticizers come from different
renewable and biological sources, such as cereals or oleaginous plants, or a waste of
agricultural industries (Reports 2017).
Starches and cellulose, extracted from rice, potatoes and straw fibres, are natural
sources for bio-based plasticizers. Sugar derivatives, such as sugar alcohols and
isosorbide esters, obtained by chemical modification of glucose or mannose, are
suitable renewable plasticizers. Sugar alcohols are polyols used for the plasticization
of starch, in mixture with glycerol. Isosorbide esters, obtained by double esterification
of isosorbide and long-chain acids, are effective plasticizers of PVC due to their
structure, similar to phthalates.
From citrus fruits and sugarcane, citrate-based plasticizers are obtained. These
esters of citric acid are used as plasticizers of PVC, cellulose and PLA.
Glycerol, the main by-product of biodiesel synthesis, is well known to be a suitable
plasticizer for starch thanks to the presence of three hydroxyl groups.
Recently, cardanol and its derivatives have been reported as precursors of bioplasticizers. The chemical structure of cardanol is quite similar to one of the most
famous phthalates like DEHP. For this reason, it shows good miscibility with PVC
and it can be used as a secondary plasticizer.
Bio-plasticizers can be also found out by natural wastes, such as tannins or derivatives of tannic acid for cement and sugar bagasse for cellulose acetate. Also, liquefied
wood esters have shown good plasticizing properties.
Another important aspect that spurs the bio-plasticizers market concerns recent
advances on bio-based plastics due to petroleum-raw resource depletion. As
the demand for bio-plastics continuously grows, also the demand for new bioplasticizers, with new properties and performances, and compatible additives grow
in parallel. The principal biodegradable polymers are synthesized from biomass like
agro-resources or obtained by microbial fermentation, such as PLA, PHA, PBSA,
PHBv.