IP Library › Granted Patent US 12,624,502
Granted Patent B2
US 12,624,502 · App. 18/026,653 · Granted May 12, 2026

Lignocellulosic bioplastics and composites, and methods for forming and use thereof

Inventors: Liangbing Hu (Rockville, MD); Chaoji Chen (Wuhan City, CN); Qinqin Xia (Harbin City, CN)
Assignee: UNIVERSITY OF MARYLAND, COLLEGE PARK
D21H11/20
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Quick Facts
Patent No.
US 12,624,502
App. No.
18/026,653
Granted
May 12, 2026
Kind
B2
Abstract

A solid lignocellulosic bioplastic can be formed from a biomass comprising an intertwined structure of lignin, hemi-cellulose, and cellulose. The lignin in the biomass can be dissolved such that the cellulose is fibrillated. After the lignin dissolution and cellulose fibrillation, the lignin can be regenerated in situ. The regenerated lignin can be deposited on and can form hydrogen bonds between the fibrillated cellulose, so as to form a slurry of lignin-cellulose solids in solution. The slurry can then be dried to form the bioplastic. In some embodiments, the lignin is dissolved by immersing the biomass in a first chemical. The lignin can then be regenerated in situ by addition of a second chemical to the first chemical.

Claims (46)

1 . A method comprising:

(a) subjecting a biomass to a first chemical treatment by immersing the biomass in a first solution comprising a deep eutectic solvent that comprises choline chloride and oxalic acid, the biomass comprising an intertwined structure of lignin, hemicellulose, and cellulose, the intertwined structure being comprised of microbundles having a cross-sectional diameter of at least 50 μm, the first chemical treatment being effective to dissolve the lignin in the biomass and to fibrillate the cellulose into microfibrils, nanofibrils, or both microfibrils and nanofibrils;

(b) after (a), adding one or more second chemicals to the first solution and then mechanically agitating for a predetermined time such that at least some of the dissolved lignin is in situ regenerated, the regenerated lignin being deposited on the cellulose microfibrils and/or nanofibrils and forming hydrogen bonds between adjacent ones of the cellulose microfibrils and/or nanofibrils;

(c) after (b), removing the deep eutectic solvent from the first solution while retaining the regenerated lignin and cellulose microfibrils and/or nanofibrils in the first solution so as to form a slurry of lignin-cellulose solids in solution; and

(d) after (c), drying the slurry to form a solid lignocellulosic bioplastic from the lignin-cellulose solids, the bioplastic comprising an interconnected network formed by the cellulose microfibrils and/or nanofibrils bound together by the regenerated lignin.

2 . The method of claim 1 , further comprising:

after (c) and prior to (d), depositing the slurry in a mold or cast,

wherein the mold or cast defines a shape of the lignocellulosic bioplastic after (d).

3 . The method of claim 1 , further comprising:

after (c) and prior to (d), depositing the slurry using a printhead or additive manufacturing nozzle,

wherein locations of the depositing define a shape of the lignocellulosic bioplastic after (d).

4 . The method of claim 1 , wherein the biomass comprises wood, bamboo, grass, hemp, or reed.

5 . The method of claim 1 , wherein, after (a):

the lignin in the slurry has β-O-4 ether bonds cleaved as compared to native lignin in the biomass prior to (a);

hydroxyl groups of the lignin are more phenolic than before (a); and

a —COO functional group of the cellulose has a negative charge.

6 . The method of claim 1 , wherein:

after (a), each of the microfibrils and/or nanofibrils has a cross-sectional dimension less than or equal to 300 nm.

7 . The method of claim 1 , wherein:

at least 90% of lignin in the biomass prior to (a) is retained in the slurry after (c); and

less than or equal to 10% of hemicellulose in the biomass prior to (a) is retained in the slurry after (c).

8 . The method of claim 1 , wherein:

(c) the drying of (d) comprises pressing the slurry while removing the one or more second chemicals therefrom.

9 . The method of claim 1 , further comprising:

prior to (d), adding a polymer or a precursor thereof to the first solution,

wherein, after (d), the solid bioplastic is a hybrid structure formed by a combination of lignin-cellulose solids and the polymer.

10 . The method of claim 9 , wherein the polymer comprises a natural resin or rosin, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polycarbonate (PC), polyethylene glycol (PEO), polyamide (PA), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyacrylonitrile (PAN), polycaprolactam (Nylon 6), poly(m-phenylene isophthalamide) (PMIA), poly(p-phenylene terephthalamide) (PPTA), polyurethane (PU), polypropylene (PP), high-density polyethylene (HDPE), polystyrene (PS), polycaprolactone (PCL), polybutylene succinate (PBS), polyglycolide (PGA), acrylonitrile butadiene styrene (ABS), polymethylsilane (PMS), or any combination of the foregoing.

11 . The method of claim 1 , wherein after (c) and prior to (d), a content of lignin-cellulose solids in the slurry is in a range of 5 wt % to 20 wt %, inclusive.

12 . The method of claim 1 , wherein the one or more second chemicals comprises water.

13 . The method of claim 1 , wherein the removing of (c) comprises filtering to separate the deep eutectic solvent and at least some of the one or more second chemicals from the first solution.

14 . The method of claim 13 , further comprising:

(e) after (c), separating the deep eutectic solvent from the one or more second chemicals,

wherein:

the separated deep eutectic solvent is reused to dissolve lignin in another biomass;

the separated second chemicals are reused in another first solution for in situ regeneration of lignin; and

the separating of (e) comprises filtration, distillation, or both.

15 . The method of claim 1 , further comprising:

after (d), pressing the solid lignocellulosic bioplastic to form a densified bioplastic.

16 . The method of claim 1 , wherein:

the one or more second chemicals comprises water;

during the first chemical treatment of (a), the first solution is maintained at a first temperature of at least 90° C. for a first time; and

the predetermined time for the mechanically agitating in (b) is 0.5-4 hours, inclusive.

17 . The method of claim 16 , wherein the first temperature is about 110° C.

18 . The method of claim 1 , wherein:

the first chemical treatment of (a) is also effective to dissolve the hemicellulose in the biomass; and

after (b), at least part of the hemicellulose remains dissolved in the first solution.

Continuity (2)
Provisional Application 63079287 · Sep 16, 2020
Related Publication 20230340728A1 · Oct 26, 2023
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