Limonene-based, non-halogenated flame retardants for polymeric applications
A limonene-based flame-retardant compound, a method of making a flame-retardant polymer, and an article of manufacture comprising a material that includes a limonene-based flame-retardant compound are provided. In an embodiment, the method includes forming a limonene-based derivative; forming a phosphorus-based flame-retardant molecule; reacting the limonene-based derivative with the phosphorus-based flame-retardant molecule to form a limonene-based flame-retardant compound; and forming a flame-retardant polymer from the limonene-based flame-retardant compound. In some embodiments, the limonene-based flame-retardant compound has variable functionality including vinyl, epoxide, methylene bridges, and thioethers.
1. A method of forming a limonene-based polymer, comprising:
reacting a limonene-based derivative with a phosphorous-containing molecule to form a limonene-based compound having the structure
each FR includes a phosphonate group, and
each R is independently alkyl, substituted alkyl, alkenyl, or substituted alkenyl; and
polymerizing the limonene-based compound to form the limonene-based polymer.
2. The method of claim 1 , wherein the limonene-based derivative is synthesized from limonene that has been obtained from a bio-based source.
3. The method of claim 1 , wherein the phosphorus-containing molecule is represented by formula
wherein:
X is chlorine or hydroxyl,
R′ is alkyl, substituted alkyl, aryl, or substituted aryl, and
R is an allyl group, an alkenyl group, an epoxy group, a carbonate group, or a thioether group.
4. The method of claim 1 , wherein the polymerizing comprises performing a base-initiated polymerization or a Ziegler-Natta type polymerization.
5. The method of claim 1 , wherein the substituted alkyl includes an epoxide functional group or a carbonate functional group.
6. The method of claim 1 , wherein the substituted alkyl includes one or more of
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphonate group.
7. The method of claim 1 , wherein each R is a hydroxyl-functionalized limonene.
8. The method of claim 1 , wherein the substituted alkyl is
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphonate group.
9. The method of claim 1 , wherein the substituted alkyl is
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphonate group.
10. A method of forming a polymer, comprising:
reacting a limonene-based derivative with a phosphorous-containing molecule to form a limonene-based compound having the structure
each FR includes a phosphonate group, and
each R is independently alkyl, substituted alkyl, alkenyl, or substituted alkenyl; and
chemically reacting the limonene-based compound with one or more polymers to form the polymer.
11. The method of claim 10 , wherein the one or more polymers comprises polyhydroxylurethanes, polycarbonates, polymers obtained by radical polymerization, polyurethanes, polyesters, polyacrylates, polyimides, polyureas, polyamides, or poly(vinyl-esters).
12. The method of claim 10 , wherein the substituted alkyl includes an epoxide functional group or a carbonate functional group.
13. The method of claim 10 , wherein the substituted alkyl includes one or more of
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphonate group.
14. The method of claim 10 , wherein each R is a hydroxyl-functionalized limonene.
15. The method of claim 10 , wherein the substituted alkyl is
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphonate group.
16. A method of forming a composition, comprising:
reacting a limonene-based derivative with a phosphorous-containing molecule to form a limonene-based compound having the structure
each FR includes a phosphonate group, and
each R is independently alkyl, substituted alkyl, alkenyl, or substituted alkenyl; and
blending the limonene-based compound with one or more polymers to form the composition.
17. The method of claim 16 , wherein the one or more polymers comprises polyhydroxylurethanes, polycarbonates, polymers obtained by radical polymerization, polyurethanes, polyesters, polyacrylates, polyimides, polyureas, polyamides, or poly(vinyl-esters).
18. The method of claim 16 , wherein the substituted alkyl includes one or more of
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphonate group.
19. The method of claim 16 , wherein each R is a hydroxyl-functionalized limonene.
20. The method of claim 16 , wherein the substituted alkyl is
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphonate group.