# US 8,569,428 B2 · High modulus polymer composites and methods of making the same

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- Number: US 8,569,428 B2
- Document ID: US8569428B2
- Status: Granted
- Kind: B2
- Application number: 12/480,599
- Filed: 2009-06-08
- Published: 2009-11-26
- Granted: 2013-10-29
- Earliest claimed: 2005-03-11
- Applicants: John R. Dorgan; Birgit Braun
- Inventors: John R. Dorgan; Birgit Braun
- Web page: https://patentgrep.com/patent/US8569428B2

## CPC

- C08J 5/045: {with vegetable or animal fibrous material}
- B29C 48/022: {characterised by the choice of material}
- B29C 48/04: Particle-shaped (making granules B29B9/00)
- B29C 48/362: {using static mixing devices}
- B29K 2105/0002: {monomers or prepolymers}
- B29K 2105/06: containing reinforcements, fillers or inserts
- C08J 2367/04: Polyesters derived from hydroxy carboxylic acids, e.g. lactones (C08J2367/06 takes precedence)
- Y10T 428/2991: Coated
- Y10T 428/2998: including synthetic resin or polymer
- 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)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The invention provides methods of producing composite polymers by combining fillers with polymers in the presence of pre-formed high molecular weight polymer. Monomer polymerization can be initiated through the addition of initiators or by reactive chemical groups on the surface of the fibers. The composite materials formed possess superior mechanical properties compared to similar polymer composites made by either purely mechanical mixing or solely polymerization of monomers in the presence of the fillers.

## Claims

### Claim 1

A method comprising:
mixing a filler simultaneously with a monomer and a pre-formed polymer, wherein the monomer reacts to form a grafted polymer layer on the surface of the filler,
wherein an interchange reaction takes place between the grafted polymer layer on the surface of the filler and the pre-formed polymer to form a composite polymer;
wherein the monomer is a lactide and the pre-formed polymer is polylactide
wherein the mixing is conducted in the presence of a catalyst that catalyzes the interchange reaction between the monomer and the pre-formed polymer on the surface of the filler.

### Claim 2 (depends on 1)

The method of claim 1, further comprising stopping a polymer reaction by contacting the pre-formed polymer with a compound that deactivates the catalyst.

### Claim 3 (depends on 1)

The method of claim 1, wherein the catalyst is selected from the group consisting of titanium(IV) isopropoxide (TIP), dibutyl tin oxide (DBTO), an alkyl tin(IV) compound, monobutyltin trichloride (BuSnC13), and TBD (1,5,7-triazabiscyclo[4.4.0]dec-5-ene).

### Claim 4 (depends on 1)

The method of claim 1, wherein the catalyst is an acid catalyst, wherein the acid catalyst is selected from the group consisting of sulfonic acids, and sulfuric acids.

### Claim 5 (depends on 1)

The method of claim 1, wherein the catalyst is a base catalyst, wherein the base catalyst is selected from the group consisting of sodium methylate, sodium methoxide, potassium methoxide, sodium hydroxides potassium hydroxide and organic base catalysts.

### Claim 6 (depends on 5)

The method of claim 5, wherein the organic base catalyst is selected from the group consisting of triethylamine, piperidine, 1,2,2,6,6-pentamethylpiperidine, pyridine, 2,6-di-tert- butylpyridine, 1,3-disubstituted tetrakis(fluoroalkyl)distannoxanes, 4-dimethyl-aminopyridine (DMAP) and guanidine.

### Claim 7 (depends on 1)

The method of claim 1, wherein the catalyst is selected from the group consisting of basic zeolites, cesium-exchanged NaX faujasites, mixed magnesium-aluminum oxides, magenesium oxide and barium hydroxide, 4-(dimethylamino)pyridine (DMAP), 4-pyrrolidinopyridine (PPY), salts of amino acids, enzyme transesterification catalysts, alkaline metal alkoxides and alkaline metal hydroxides.

### Claim 8 (depends on 1)

The method of claim 1, wherein total lactide is present at a concentration of 35 wt % as the lactide monomer and a concentration of 65 wt % as the polylactide pre-formed polymer.

### Claim 9

A method comprising:
mixing cellulose fibers with lactide and polylactide to form a premix;
contacting the premix with a composition comprising stannous octoate, triphenylphosphine, and titanium isopropoxide, to produce a composite polymer;
contacting the composite polymer with polylactide to form a stabilized composite polymer.