# US 10,501,588 B2 · Grafting method for rice straw fiber modification

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- Number: US 10,501,588 B2
- Document ID: US10501588B2
- Status: Granted
- Kind: B2
- Application number: 15/884,075
- Filed: 2018-01-30
- Published: 2018-05-31
- Granted: 2019-12-10
- Earliest claimed: 2015-08-18
- Assignees: Jiangnan University
- Applicants: Dan Huang; Lili Zhen; Xuehong Ren; Hongbo Wang
- Inventors: Dan Huang; Lili Zhen; Xuehong Ren; Hongbo Wang
- Web page: https://patentgrep.com/patent/US10501588B2

## CPC

- C08J 3/28: Treatment by wave energy or particle radiation
- C08G 18/4825: {Polyethers containing two hydroxy groups (C08G18/4833 - C08G18/5096 take precedence)}
- C08G 18/4833: {Polyethers containing oxyethylene units}
- C08G 18/6484: {Polysaccharides and derivatives thereof}
- C08G 18/6492: {Lignin containing materials; Wood resins; Wood tars; Derivatives thereof}
- C08G 18/7621: {being toluene diisocyanate including isomer mixtures}
- C08G 18/7657: {containing two or more aromatic rings}
- C08G 18/7671: {containing only one alkylene bisphenyl group}
- C08H 8/00: Macromolecular compounds derived from lignocellulosic materials {(pretreatment thereof B27N)}
- C08J 2397/02: Lignocellulosic material, e.g. wood, straw or bagasse
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08H: DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS (polysaccharides C08B; natural rubber C08C; natural resins or their derivatives C09F; bituminous materials C10)

## Abstract

The present invention relates to the field of reutilization of biomass resources, and more particularly relates to a grafting method for rice straw fiber modification. The pulverized and pretreated straw powder is first reacted with diisocyanate under ultrasonic and microwave treatment, and the resulting product is reacted with PEG to obtain the PEG grafted straw fiber polymer compound. Grafting PEG onto the straw fiber through the bridging of the diisocyanate improves the thermoplasticity of the modified rice straw fiber. The modified straw fiber of the present invention can be hot-pressed to form self-reinforced composite materials without adding additional materials, which overcomes the waste and pollution problem of traditional straw reutilization method, achieving the goal of whole straw utilization.

## Claims

### Claim 1

A Polyethylene Glycol (PEG) grafting method for rice straw fiber modification, comprising pretreating the rice straw, grafting diisocyanate to the pretreated rice straw by a simultaneous treatment of microwave and ultrasound power, and grafting PEG to the diisocyanate grafted rice straw by another microwave and ultrasound treatment.

### Claim 2 (depends on 1)

The method of claim 1, comprising the steps of:
1) pretreating the rice straw as follows: the rice straw, which has been soaked in water, cleaned and dried, is crushed to 20 to 60 mesh powder; and the rice straw powder is added to DMSO, treated at 60° C. for 60 min with a microwave power of 100 W and a ultrasonic power of 300 W, cleaned with ethanol and water, and dried in vacuum to obtain a pretreated straw powder;
2) grafting diisocyanate to the rice straw as follows: the pretreated straw powder is added to anhydrous DMSO; N2 is used to remove the O2; diisocyanate is then added to make a reaction mixture; the reaction mixture is reacted at 60° C. for 10-80 min with a microwave power of 250-400 W and an ultrasonic power of 180-450 W; and
3) grafting of PEG as follows: PEG is added to the reaction mixture of step 2), and is treated at 60° C. for 50-80 min with a microwave power of 250-400 W and an ultrasonic power of 270-540 W; the resulting product is added to ethanol, which is allowed to stand still and precipitate to remove an upper emulsion; the obtained product is then filtered, washed twice by ethanol and deionized water, and filtered again to obtain a crude product; and the crude product is dried at 80° C. in vacuum for 12 hr and extracted by toluene using soxhlet extraction at 120° C. for 12 hr to obtain a final product of PEG grafted straw fiber polymer compound.

### Claim 3 (depends on 2)

The method of claim 2, wherein the diisocyanate used in step 2) is TDI or MDI, and the molar ratio of diisocyanate to PEG is 1:1, and wherein the reaction is carried out at 60° C. for 60 min with a ultrasonic power of 270 W and a microwave power of 300 W in step 2).

### Claim 4 (depends on 2)

The method of claim 2, wherein the mass ratio of PEG to straw fiber is 1:2, and wherein the reaction is carried out at 60° C. for 70 min with a ultrasonic power of 360 W and a microwave power of 300 W in step 3).