Biodegradable composite materials
View Patent ↗A method of making a biodegradable composite is carried out by: (a) providing an aqueous mixture comprising partially hydrolyzed cellulose in a dissolution media; (b) providing a solution comprising a aliphatic polyester in a polar organic solvent; (c) combining the mixture with the solution to form a precipitate; (d) washing the precipitate with water to remove solvent and dissolution media and form a wet biodegradable composite; and then (e) drying the wet biodegradable composite to form a dry biodegradable composite. Composites made from the method are also described.
1. A method of making a biodegradable composite, comprising:
(a) providing an aqueous mixture comprising partially hydrolyzed cellulose in a dissolution media;
(b) providing a solution comprising a aliphatic polyester in a polar organic solvent;
(c) combining said mixture with said solution to form a precipitate; and then
(d) washing said precipitate with water to remove solvent and dissolution media and form a wet biodegradable composite; and then
(e) drying said wet biodegradable composite to produce a dry biodegradable composite.
2. The method of claim 1 , wherein said biodegradable composite is rigid.
3. The method of claim 1 , wherein said biodegradable composite is porous.
4. The method of claim 1 , wherein said biodegradable composite has a density of 0.05 to 1 grams per cubic centimeter.
5. The method of claim 1 , wherein said washing step is carried out until said wet biodegradable composite has a neutral pH.
6. The method of claim 1 , wherein said drying step is carried out at room temperature, with heating, or during cooling, and wherein said drying step is carried out at atmospheric pressure or at a reduced pressure.
7. The method of claim 1 , wherein said aliphatic polyester is selected from the group consisting of polylactic acid, polyglycolic acid, polycaprolactone, polybutylene succinates, polyhydroxyalkanoates, and combinations thereof.
8. The method of claim 1 , wherein said polar organic solvent comprises tetrahydrofuran, chloroform, or combinations thereof.
9. The method of claim 1 , wherein said dissolution media comprises an acid solution.
10. The method of claim 1 , wherein:
said aliphatic polyester is selected from the group consisting of polylactic acid, polyglycolic acid, polycaprolactone, polybutylene succinates, polyhydroxyalkanoates, and combinations thereof;
said polar organic solvent comprises tetrahydrofuran, chloroform, or combinations thereof; and
said dissolution media comprises a sulfuric acid solution; and wherein said dry biodegradable composite has:
(i) a storage modulus of from 1 to 25 gigapascals at a temperature of 20 degrees C.;
(ii) a storage modulus of from 1 to 10 gigapascals at a temperature of 100 degrees Centigrade; and
(iii) a density of 0.1 to 0.5 grams per cubic centimeter.
11. The method of claim 1 , wherein said combining step and said washing step are carried out in a form or mold; and said method further comprises the step of:
(e) releasing said biodegradable composite from said form or mold before or after said drying step to produce a biodegradable composite article.
12. The method of claim 11 , further comprising the step of:
(f) cutting or grinding said article to further define the features thereof.
13. The method of claim 11 , further comprising the step of:
(g) grinding said article to form a particulate biodegradable composite.
14. A particulate biodegradable composite produced by the process of claim 13 .
15. The particulate biodegradable composite of claim 14 , wherein said particulate is a pharmaceutical tablet filler.