CHEMICAL MODIFICATION OF LIGNIN AND LIGNIN DERIVATIVES

1 . A method for producing a trans-esterified hydroxypropyl lignin (HPL), the method comprising:

precipitating a lignin;

dissolving the precipitated lignin in a solution;

adding a reagent to the solution;

adjusting a pH of the solution;

allowing reactions in the solution to occur for a predetermined amount of time;

precipitating the solution to produce a precipitate; and

washing, filtering, and drying the precipitate to produce the trans-esterified HPL.

2 . The method of claim 1 , wherein the HPL is a Kraft lignin precipitated by a Lignoboost process.

3 . The method of claim 1 , wherein the lignin is dissolved in a sodium hydroxide solution.

4 . The method of claim 3 , wherein the sodium hydroxide solution is about four percent to about six percent sodium hydroxide.

5 . The method of claim 1 , wherein the pH of the solution is adjusted to a range of about 11.5 pH to about 12.5 pH

6 . The method of claim 1 , wherein the reagent is propylene oxide.

7 . The method of claim 6 , wherein a total weight of the propylene oxide added to the solution is about half a total weight of the precipitated lignin in the solution.

8 . The method of claim 1 , wherein the solution is precipitated by reducing the pH to below about 2.5 pH.

9 . The method of claim 8 , further comprising:

adding sulfuric acid to reduce the pH.

10 . A trans-esterified lignin/thermoplastic blend comprising:

a trans-esterified hydroxypropyl lignin (HPL), wherein the trans-esterified HPL is created by:

precipitating a lignin;

dissolving the precipitated lignin in a solution;

adding a reagent to the solution;

adjusting a pH of the solution;

allowing reactions in the solution to occur for a predetermined amount of time;

precipitating the solution to produce a precipitate; and

washing, filtering, and drying the precipitate to produce the trans-esterified HPL; and

a thermoplastic.

11 . The trans-esterified lignin/thermoplastic blend of claim 10 , wherein the HPL is a Kraft lignin precipitated by a Lignoboost process.

12 . The trans-esterified lignin/thermoplastic blend of claim 10 , wherein the lignin is dissolved in a sodium hydroxide solution and the sodium hydroxide solution is about four percent to about six percent sodium hydroxide.

13 . The trans-esterified lignin/thermoplastic blend of claim 10 , wherein the reagent is propylene oxide and a total weight of the propylene oxide added to the solution is about half a total weight of the precipitated lignin in the solution.

14 . The trans-esterified lignin/thermoplastic blend of claim 10 , wherein the solution is precipitated by adding sulfuric acid to reduce the pH to below about 2.5 pH.

15 . A method for producing a biodegradable plastic, the method comprising:

extruding a trans-esterified lignin/thermoplastic blend, the trans-esterified lignin/thermoplastic blend comprising:

a trans-esterified hydroxypropyl lignin (HPL), wherein the trans-esterified HPL is created by:

precipitating a lignin;

dissolving the precipitated lignin in a solution;

adding a reagent to the solution;

adjusting the pH of the solution;

allowing reactions in the solution to occur for a predetermined amount of time;

precipitating the solution to produce a precipitate; and

washing, filtering, and drying the precipitate to produce the trans-esterified HPL; and

a thermoplastic.

16 . The method of claim 15 , wherein an alkyl ester of the HPL exchanges carboxylic acid groups with an alcohol terminated segment of a polyester chain such that long chain polyester segments are covalently-bond to the HPL.

17 . The method of claim 15 , wherein the extent of transesterification of the lignin/thermoplastic blend is controlled such that extensive crosslinking does not occur in order to retain thermoplastic properties.

18 . The method of claim 15 , wherein the biodegradable plastic is a film product, a formed and molded product, an injection molded product, or an extruded product that biodegrades over a period of time into humus through an oxidative process.

19 . The method of claim 18 , wherein polylactide is added to the lignin/thermoplastic blend to extend the period of time that the biodegradable plastic biodegrades.

20 . The method of claim 15 , wherein the trans-esterified HPL includes HPL and a polyester.