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. 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 limonene-based flame-retardant compound having the structure
wherein:
each FR includes a phosphonate group; and
each R is independently alkyl or substituted alkyl.
2. The limonene-based flame-retardant compound of claim 1 , wherein the substituted alkyl includes an alkene functional group.
3. The limonene-based flame-retardant compound of claim 1 , wherein the substituted alkyl includes an epoxide functional group.
4. The limonene-based flame-retardant compound of claim 1 , wherein the substituted alkyl includes a carbonate functional group.
5. The limonene-based flame-retardant compound 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.
6. The limonene-based flame-retardant compound of claim 1 , wherein is a hydroxyl-functionalized limonene.
7. The limonene-based flame-retardant compound of claim 5 , wherein y is 1.
8. The limonene-based flame-retardant compound 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 limonene-based flame-retardant compound 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. The limonene-based flame-retardant compound 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.
11. A limonene-based flame-retardant compound having the structure
wherein:
each FR includes a phosphate group or a phosphonate group; and
each R is independently
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphate group or phosphonate group.
12. The limonene-based flame-retardant compound of claim 11 , wherein y is 1.
13. The limonene-based flame-retardant compound of claim 11 , wherein FR is the phosphate group.
14. The limonene-based flame-retardant compound of claim 11 , wherein FR is the phosphonate group.
15. A limonene-based flame-retardant compound having the structure
wherein:
each FR includes a phosphate group; and
each R is independently
wherein:
y is an integer between 1 and 12, and
the dotted line bond indicates a connection to the phosphate group or phosphonate group.
16. The limonene-based flame-retardant compound of claim 15 , wherein y is 1.