Phosphonate-substituted lignin as a flame retardant
View Patent ↗Modified lignin having covalently attached phosphorous containing groups and methods for preparing such compounds are described herein. The modified lignin described herein provides a renewable source of flame retardant material.
1. A flame retardant comprising:
a lignin covalently bonded with a phosphorous containing component, the phosphorous containing component comprising a compound of general formula:
wherein:
X 1 and X 2 are, phosphine, phosphine oxide, phosphinite, phosphonite, phosphinate, phosphonate, or phosphate;
m 1 is an integer of 1 to 10; and
m 2 is an integer of 1 to 10.
2. The flame retardant of claim 1 , wherein each of X 1 and X 2 are independently substituted at one or more positions with a substituent R, wherein R is independently selected from a group containing C 1 to C 18 alkyl, C 2 to C 18 alkenyl, C 2 to C 18 alkynyl, C 5 to C 20 cycloalkyl, and C 5 to C 20 aryl.
3. The flame retardant of claim 1 , wherein the phosphorous containing component comprises:
4. The flame retardant of claim 1 , wherein the phosphorous containing component comprises about 0.1% to about 50% by weight to the flame retardant.
5. The flame retardant of claim 1 , wherein the lignin comprises lignin sulfonates, Kraft lignins, soda lignins, organosolv lignins, softwood lignin, hardwood lignin, cellulosic grasses lignins, corn stover lignins, steam explosion lignins, or combinations thereof.