# US 11,111,378 B2 · Bulk transient materials made of cyclic poly(phthalaldehyde)

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- Number: US 11,111,378 B2
- Document ID: US11111378B2
- Status: Granted
- Kind: B2
- Application number: 16/383,316
- Filed: 2019-04-12
- Published: 2019-10-17
- Granted: 2021-09-07
- Earliest claimed: 2018-04-16
- Assignees: The Board of Trustees of the University of Illinois
- Applicants: The Board of Trustees of the University of Illinois
- Inventors: Jeffrey S. Moore; Scott R. White; Nancy R. Sottos; Adam M. Feinberg; Christopher L. Plantz; Hector Lopez-Hernandez; Evan M. Lloyd
- Web page: https://patentgrep.com/patent/US11111378B2

## CPC

- C08L 61/02: Condensation polymers of aldehydes or ketones only
- C08J 5/18: Manufacture of films or sheets
- C08K 5/0016: {Plasticisers}
- C08K 5/005: {Stabilisers against oxidation, heat, light, ozone}
- C08K 5/06: Ethers; Acetals; Ketals; Ortho-esters
- C08K 5/12: of cyclic polycarboxylic acids
- C08K 5/18: with aromatically bound amino groups
- C08K 5/3432: Six-membered rings
- B01J 27/10: Chlorides
- B01J 27/135: with titanium, zirconium, hafnium, germanium, tin or lead
- B01J 27/138: with alkaline earth metals, magnesium, beryllium, zinc, cadmium or mercury
- C08K 3/012: Additives activating the degradation of the macromolecular compounds
- C08K 5/0033: {Additives activating the degradation of the macromolecular compound}
- C08K 5/17: Amines; Quaternary ammonium compounds
- C08K 5/3435: Piperidines
- C08L 2201/08: Stabilised against heat, light or radiation or oxydation
- C08L 2203/16: used for films
- C08L 2203/30: used for thermoforming
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- 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)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

The present disclosure provides a composition of matter comprising purified cyclic poly(phthalaldehyde) (cPPA) and a plasticizer. The composition enables thermal processing and molding in bulk quantities, and is designed to degrade when contacted by an acid or exposed to a high enough temperature. Photodegradable cPPA containing a photooxidant is disclosed. Methods of making and recycling the composition of matter are also provided.

## Claims

### Claim 1

A composition, comprising:
cyclic poly(phthalaldehyde) (cPPA);
a Lewis acid catalyst in an amount of less than about 10 μmol/g; and
a plasticizer.

### Claim 2 (depends on 1)

The composition of claim 1, wherein the Lewis acid catalyst is titanium tetrachloride, boron trifluoride, tin(IV) chloride, aluminum chloride, zinc chloride, an alkyl aluminum. chloride, or any combination thereof.

### Claim 3 (depends on 1)

The composition of claim 1, wherein the plasticizer is selected from the group consisting of: dimethylphthalate, diethylphthalate, dibutylphthalate, dihexylphthalate, dioctylphthalate, an arene, a long-chain alkyl ether, and any combination thereof.

### Claim 4 (depends on 1)

The composition of claim 1, further comprising a stabilizer comprising at least one of an arene, a long-chain alkyl ether, a sacrificial reductant, an organic base, a nucleophile, pyridine, an alkylamine, or an alcohol.

### Claim 5 (depends on 1)

The composition of claim 1, further comprising a stabilizer selected from one or more of anisole; 1,4-dimethoxybenzene; 1,3,5-trimethoxybenzene, 1,2,4-trimethoxybenzene; diphenyl ether; biphenyl, aniline; or any other organic compound with an oxidation potential lower than that of cPPA.

### Claim 6 (depends on 1)

The composition of claim 1, further comprising a stabilizer selected from the group consisting of: (2,2,6,6 tetramethylpiperidin-1-yl)oxyl (TEMPO), N,N′-di-sec -butyl-1,4 -phenylenediamine (DBPDA), and any combination thereof.

### Claim 7 (depends on 1)

The composition of claim 1, wherein the cPPA degrades when contacted by an acid or exposed to a temperature of about 120 to about 200° C.

### Claim 8 (depends on 7)

The composition of claim 7, wherein the acid comprises a strong mineral or an organic acid.

### Claim 9 (depends on 7)

The composition of claim 7, wherein the acid comprises one or more of hydrochloric acid, sulfuric acid, acetic acid, or trifluoroacetic acid.

### Claim 10 (depends on 1)

A bulk transient material, comprising the composition of claim 1 and a photooxidant.

### Claim 11 (depends on 1)

A device made at least in part from the composition of claim 1.

### Claim 12

A method for stabilizing cyclic poly(phthalaldehyde) (cPPA) to enable thermal processing of a bulk solid, the method comprising:
purifying cPPA by lowering a concentration of a Lewis acid catalyst to less than about 10 μmol/g; and
adding a plasticizer to the cPPA.

### Claim 13 (depends on 12)

The method of claim 12, wherein the purifying of cPPA comprises dropwise precipitation of the cPPA into a solvent, resulting in a purified cPPA having a concentration of the Lewis acid catalyst of less than about 10 μmol/g.

### Claim 14 (depends on 12)

The method of claim 12, further comprising adding a stabilizer to the cPPA.

### Claim 15

A method of manufacturing a bulk transient material capable of triggered depolymerization, the method comprising:
purifying cyclic poly(phthalaldehyde) (cPPA) by lowering a concentration of a Lewis acid catalyst to less than about 10 μmol/g;
dissolving the purified cPPA in a first portion of a solvent to form a purified cPPA solution;
dissolving a plasticizer in a second portion of the solvent to form a plasticizer solution;
mixing the purified cPPA solution with the plasticizer solution to form a mixture;
casting the mixture into a film to obtain a cPPA film;
drying the cPPA film;
melting the dried cPPA film;
adding the melted cPPA into a mold;
cooling the melted cPPA to solidify the cPPA; and
removing the solidified cPPA from the mold to obtain a bulk transient material capable of triggered depolymerization.

### Claim 16 (depends on 15)

The method of claim 15, further comprising dissolving a stabilizer in the second portion of the solvent with the plasticizer.

### Claim 17 (depends on 15)

The method of claim 15, further comprising dissolving an oxidant or a photooxidant in the second portion of the solvent.

### Claim 18

A method of recycling a material comprising cyclic poly(phthalaldehyde)(cPPA), comprising:
heating the material comprising cPPA to a temperature at or above a depolymerization temperature of the cPPA so as to provide degraded cPPA; and
recovering monomers from degraded cPPA.

### Claim 19 (depends on 18)

The method of claim 18. wherein the heating the material is conducted under vacuum.

### Claim 20 (depends on 18)

The method of claim 18, wherein the material further comprises a fiber.