Solvents for PLA
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David Price
Sep 4, 2012, 1:57:51 AM9/4/12
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According to most technical references I have seen PLA is not soluble in Acetone yet there were various reports in forums that it was ...
In my occaisional research on the topic (WARNING: not rigorous or efficient as my graduate organic chemistry is nearly 40 years out of date) I think I may have come across the answer to this dichotomy which is to do with chirality. Organic molecules can adopt different 3D conformations and in some cases you can have stereoisomer forms which are mirrior images of each other that cannot be superimposed (chirals). These two forms are called enantiomers and while not of too much interest in general graduate organic chemistry it is very important in biochemistry and pharmacology.
http://en.wikipedia.org/wiki/Enantiopure is a useful starting point if you want to find out more about the above properties.
An enantiopure sample of PLA, where there is a single enantiomer, will not be soluble in Acetone. However, a non-enantiopure sample which has a mixture of enantiomers, is soluble in Acetone.
The reference I found is;
It lists the following as solvents for Polylactide (PLA)
Enantiopure form solvents - chloroform and other chlorinated organic solvents, such as furan, dioxane, dioxolane and pyridine are good solvents. (other references state that Benzene is also a good solvent but I would avoid it like the plague)
Non-enantiopure form solvents - ethyl acetate, dimethylsulfoxide, tetrahydrofuran, acetone, xylene, MEK (methyl ethyl ketone), ethyl lactate and dimethylformamide.
PLA is not soluble in water, alcohol (e.g. ethanol, methanol), isopropyl ether, or unsubstituted hydrocarbons (e.g. cyclohexane, heptane).
I am NOT ADVOCATING you try out these different solvents merely sharing the information as a step in the process of understanding how we can better exploit PLA and hopefully answering the question of how laymen can dissolve PLA in acetone when the chemistry texts say it can't.
David
In my occaisional research on the topic (WARNING: not rigorous or efficient as my graduate organic chemistry is nearly 40 years out of date) I think I may have come across the answer to this dichotomy which is to do with chirality. Organic molecules can adopt different 3D conformations and in some cases you can have stereoisomer forms which are mirrior images of each other that cannot be superimposed (chirals). These two forms are called enantiomers and while not of too much interest in general graduate organic chemistry it is very important in biochemistry and pharmacology.
http://en.wikipedia.org/wiki/Enantiopure is a useful starting point if you want to find out more about the above properties.
An enantiopure sample of PLA, where there is a single enantiomer, will not be soluble in Acetone. However, a non-enantiopure sample which has a mixture of enantiomers, is soluble in Acetone.
The reference I found is;
Biopolymers: Biomédical and Environmental Applications
Edited by Susheel Kalia and Luc Avérous
Wiley, 2011, ISBN 978-0-470-63923-8It lists the following as solvents for Polylactide (PLA)
Enantiopure form solvents - chloroform and other chlorinated organic solvents, such as furan, dioxane, dioxolane and pyridine are good solvents. (other references state that Benzene is also a good solvent but I would avoid it like the plague)
Non-enantiopure form solvents - ethyl acetate, dimethylsulfoxide, tetrahydrofuran, acetone, xylene, MEK (methyl ethyl ketone), ethyl lactate and dimethylformamide.
PLA is not soluble in water, alcohol (e.g. ethanol, methanol), isopropyl ether, or unsubstituted hydrocarbons (e.g. cyclohexane, heptane).
I am NOT ADVOCATING you try out these different solvents merely sharing the information as a step in the process of understanding how we can better exploit PLA and hopefully answering the question of how laymen can dissolve PLA in acetone when the chemistry texts say it can't.
David
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