Patent Application
20160194417
Food packaging is a major contributor to environmental pollution. Vast amounts of garbage are increasingly making an appearance in the middle of the ocean, and the garbage is largely made up of food packaging materials. Marine life can become entangled in the garbage or ingest the garbage, which can lead to death of an individual species or even extinction of an entire species. Disposed food packaging materials can be equally destructive on land. Many animals feed on food wastes at waste disposal sites. Entire ecosystems can be formed around these sites. The food wastes can be harmful to the animals when ingested. Like marine life, land animals can also consume the plastics used in food packaging materials. The consumed plastics can leach harmful materials into the animal or disrupt their digestive tract causing harm. Disposed food packaging materials are therefore rapidly exhausting landfills and harming wildlife.
Billions of pounds of various products are used to manufacture food packaging materials. Can coatings is a market worth in excess of three billion dollars. The US food packaging demand is projected to reach $25 billion in 2013. Despite the large market and constant technological progress, most new materials used in food packaging have not been fully evaluated in terms of either food safety or their environmental impact. The most widely used packaging materials, such as plastics, are manufactured from fossil fuels and other non-renewable sources, and are therefore not fully recyclable or biodegradable. Disposal of those packaging materials into landfills can contaminate soil and waterways, eventually causing harm to ecosystems and wildlife; all of which add to the economic and social impact of the use of such materials. The food packaging industry is working towards environmental sustainability, progress of which will include the development of new and environmentally-friendly packaging materials.
In an embodiment, a polymer resin having a polymeric backbone, includes a first repeating unit and a second repeating unit, wherein the first repeating unit has a two-photon absorbing chromophore in the polymeric backbone. The two-photon absorbing chromophore may be any two-photon absorbing chromophore known in the art.
In an embodiment, a recyclable material includes a polymer resin having a polymeric backbone, the polymer resin including a first repeating unit and a second repeating unit, wherein the first repeating unit has a two-photon absorbing chromophore in the polymeric backbone. The two-photon absorbing chromophore may be any two-photon absorbing chromophore known in the art.
In an embodiment, a method of preparing a polymer resin includes polymerizing a first monomer and a second monomer, wherein the first monomer has a two-photon absorbing chromophore, and wherein the two-photon absorbing chromophore is incorporated into a backbone of the polymer resin. The two-photon absorbing chromophore may be any two-photon absorbing chromophore known in the art.
In an embodiment, a method of degrading a polymer includes exposing the polymer to light, the polymer including a first repeating unit and a second repeating unit, wherein the first repeating unit has a two-photon absorbing chromophore in a polymeric backbone of the polymer. The two-photon absorbing chromophore may be any two-photon absorbing chromophore known in the art.
For a fuller understanding of the nature and advantages of the disclosed embodiments, reference can be made to the following detailed description in connection with the accompanying figures.
Before the present compositions and methods are described, it is to be understood that they are not limited to the particular compositions, methodologies or protocols described, as these may vary. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit their scope.
“Alkenylene” refers to a divalent alkenyl moiety, meaning the alkenyl moiety is attached to the rest of the molecule at two positions. Alkenylene groups may be substituted or unsubstituted.
“Alkenyl” means a straight or branched alkyl group having one or more double carbon-carbon bonds and 2-20 carbon atoms, including, but not limited to, ethenyl, 1-propenyl, 2-propenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, and the like. In some embodiments, the alkenyl chain is from 2 to 10 carbon atoms in length, from 2 to 8 carbon atoms in length, from 2 to 6 carbon atoms in length, or from 2 to 4 carbon atoms in length.
“Arylene” means a bivalent aryl group that links one group to another group in a molecule. Arylene groups may be substituted or unsubstituted.
“Aryl” means a monocyclic, bicyclic, or polycyclic (e.g., having 2, 3 or 4 fused rings) aromatic hydrocarbons. In some embodiments, aryl groups have from 6 to 20 carbon atoms or from 6 to 10 carbon atoms. Examples of aryl groups include, but are not limited to, phenyl, biphenyl, benzyl, naphthyl, anthracenyl, phenanthrenyl, indanyl, indenyl, tetrahydronaphthyl, and the like.
“Heteroaryl” means an aromatic heterocycle having up to 20 ring-forming atoms (e.g., C) and having at least one heteroatom ring member (ring-forming atom) such as sulfur, oxygen, or nitrogen. In some embodiments, the heteroaryl group has at least one or more heteroatom ring-forming atoms, each of which are, independently, sulfur, oxygen, or nitrogen. In some embodiments, the heteroaryl group has from 3 to 20 ring-forming atoms, from 3 to 10 ring-forming atoms, from 3 to 6 ring-forming atoms, or from 3 to 5 ring-forming atoms. In some embodiments, the heteroaryl group contains 2 to 14 carbon atoms, from 2 to 7 carbon atoms, or 5 or 6 carbon atoms.
“Substituted aryl” refers to aryl as just described in which one or more hydrogen atoms attached to any carbon atoms is replaced by one or more functional groups such as alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heterocycloalkyl, substituted heterocycloalkyl, halogen, halogenated alkyl (e.g., CF 3), hydroxy, amino, phosphino, alkoxy, amino, thio and both saturated and unsaturated cyclic hydrocarbons which are fused to the aromatic ring(s), linked covalently or linked to a common group such as a methylene or ethylene moiety.
“Cycloalkyl” means non-aromatic cyclic hydrocarbons including cyclized alkyl, alkenyl, and alkynyl groups that contain up to 20 ring-forming carbon atoms. Cycloalkyl groups can include mono- or polycyclic ring systems such as fused ring systems, bridged ring systems, and spiro ring systems. In some embodiments, polycyclic ring systems include 2, 3, or 4 fused rings. A cycloalkyl group can contain 3 to 15, 3 to 10, 3 to 8, 3 to 6, 4 to 6, 3 to 5, or 5 or 6 ring-forming carbon atoms. Ring-forming carbon atoms of a cycloalkyl group can be optionally substituted by oxo or sulfido. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclopentenyl, cyclohexenyl, cyclohexadienyl, cycloheptatrienyl, norbornyl, norpinyl, norcarnyl, adamantyl, and the like. Also included in the definition of cycloalkyl are moieties that have one or more aromatic rings fused (having a bond in common with) to the cycloalkyl ring, for example, benzo or thienyl derivatives of pentane, pentene, hexane, and the like (e.g., 2,3-dihydro-1H-indene-1-yl, or 1H-inden-2(3H)-one-1-yl).
“Heterocycloalkyl” means non-aromatic heterocycles having up to 20 ring-forming atoms including cyclized alkyl, alkenyl, and alkynyl groups, where one or more of the ring-forming carbon atoms is replaced by a heteroatom such as an O, N, or S atom. Hetercycloalkyl groups can be mono or polycyclic (e.g., fused, bridged, or spiro systems).
Disclosed are monomers and polymers which allow for easy decomposition of polymeric products made therefrom. The decomposed products can be used to create other high value materials and products. Environmental damage and volume of waste created from packaging materials can thus be greatly reduced. The monomers and polymers can be used in conjunction with one or more resin systems. Use of monomers having a two-photon absorbing chromophore can incorporate the chromophore into the backbone of the resin system. The two-photon absorbing chromophore is capable of absorbing two photons of high intensity light simultaneously resulting in the decomposition. The decomposition can be selective, as simultaneous absorption of two-photons of high intensity light does not occur from exposure to ambient light, whether natural or synthetic. The result of the decomposition is a fragmenting of the polymer into fragments of reduced molecular weights, which allows for the fragments to be easily processed and/or recycled.
Methods for forming such decomposable monomers and polymers are disclosed. The polymers that include the two-photon absorbing chromophore contain specific linker moieties in the polymer backbone that can be cleaved under certain conditions not encountered in ambient conditions, and are therefore stable and durable. The conditions to cleave the polymer backbone include exposure to high intensity light sources that have a photon flux sufficient to provide two photons to be absorbed simultaneously by the chromophore. The two-photon absorbing chromophore may be used in a variety of materials that use a wide variety of polymeric resins. For example, polymers such as polyethylene terephthalate (PET), polycarbonate, epoxies, polyurethane, polyurea, melamine-formaldehyde polymers, polyesters, polyethers, novolac, bakelite, nylon, polyamides, acrylics, styrenics, polyimide, polyamide-imide, condensation polymers, chain growth polymers may be modified to include the two-photon absorbing chromophore rendering component parts thereof easily reclaimable and reusable so that they do not add to landfills. In some embodiments, the modified polymeric resin, containing the two-photon absorbing chromophore maintains substantially the same or similar properties as the unmodified resin. For example, a modified PET will have substantially the same or similar properties as an unmodified PET, and is suitable as a replacement for the unmodified PET. Ambient light such as sunlight, fluorescent light, LED, flames, or incandescent light, does not provide enough energy to degrade the two-photon absorbing chromophore. Only high intensity light sources capable of delivering two photon excitation of the chromophore can provide enough energy to degrade the polymeric resin and permit separation and recovery of one or more components of the resin. The resins are exposed to high intensity light which depolymerizes them and allows for valuable chemical units and components such as monomers and small molecules to be reclaimed in pristine or near pristine condition. The reclaimed monomers can then be used to create new polymers with the physical properties that the original materials had. This is very advantageous over current recycling technologies where the polymer is difficult to depolymerize and the resulting recovered materials are greatly inferior in physical properties. The decomposable resins, and their reusable, decomposed products, have utility not only in the food packaging industry, but also in many industries where plastics are commonly used.
The two-photon absorbing chromophores described herein use a form of non-linear optics.
In
Certain aspects of non-linear optics include the ability of a molecule to absorb two quanta of energy simultaneously.
The two-photon absorbing chromophore described herein may be any two-photon absorbing chromophore known in the art. For example, in some embodiments, the two-photon absorbing chromophore may be represented by Formula I:
wherein A1 may be aryl, heteroaryl, substituted aryl, cycloalkyl, heterocycloalkyl, methine, vinyl, substituted vinyl, aryl group fused to the bonded C atom, or cyclic compound fused to the bonded C atom.
In some embodiments, A2 may be aryl, heteroaryl, substituted aryl, cycloalkyl, heterocycloalkyl, methine, vinyl, substituted vinyl, aryl group fused to the bonded C atom, or cyclic compound fused to the bonded C atom.
In some embodiments, R1 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H.
In some embodiments, R2 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H.
In some embodiments, R3 may be arylene, alkenylene, or a bivalent cyclic compound.
In some embodiments, R4 may be arylene, alkenylene, or a bivalent cyclic compound.
In some embodiments, X1 may be B, C, N, Si, O, P, S, Se, or As.
In some embodiments, X2 may be B, C, N, Si, O, P, S, Se, or As; and n is an integer from 1 to 20.
In other embodiments, the two-photon absorbing chromophore includes a moiety of Formula II:
wherein R1 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H. In some embodiments, R2 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H. In some embodiments, X1 may be B, C, N, Si, O, P, S, Se, or As; and X2 may be B, C, N, Si, O, P, S, Se, or As.
In other embodiments, the two-photon absorbing chromophore includes a moiety of Formula III:
wherein R1 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H. In some embodiments, R2 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H. In some embodiments, X1 may be B, C, N, Si, O, P, S, Se, or As; and X2 may be B, C, N, Si, O, P, S, Se, or As.
In other embodiments, the two-photon absorbing chromophore includes a moiety of Formula IV:
wherein X1 may be B, C, N, Si, O, P, S, Se, or As; and X2 may be B, C, N, Si, O, P, S, Se, or As.
In other embodiments, the two-photon absorbing chromophore includes a moiety of Formula V:
wherein R1 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H. In some embodiments, R2 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H. In some embodiments, X1 may be B, C, N, Si, O, P, S, Se, or As; and X2 may be B, C, N, Si, O, P, S, Se, or As.
Various polymer resins have the second repeating unit including, but are not limited to —C(═O)—Ar—C(═O)—CH2—CH2—O—, —C(═O)—NH—Ar—CH2—Ar—NH—C(═O)—O—CH2—CH2—O—, —C(═O)—X3—NH—, or —C(═O)—X3—O—; wherein X3=—CH((C1-C6)alkyl)-, —(CH2)n—, —Ar—C(═O)—NH—Ar—, or —(CH2)n—C(═O)—NH—(CH2)m—C(═O)—; m=2, 3, 4, 5, or 6; and n=2, 3, 4, 5, or 6. Various polymer resins have the second repeating unit including, but is not limited to R7—O—X4—O—R7—O—, wherein: R7 is —CH2—CHOH—CH2—; and X4 is —Ar—C(Me)2-Ar—, —Ar—C(CF3)2—Ar—, a novolac resin, a phenol novolac resin, a cresol novolac resin, -alkylidene-, or combination thereof. In some embodiments, Ar is a 1,4-phenylene. In other embodiments, Ar is a 1,3-phenylene. In yet other embodiments, Ar is a 1,2-phenylene. Various polymer resins have the second repeating unit including, but is not limited to —CH2—CR8R9—; wherein R8=H, or Me; R9=H, COOH, COOR10, CONR11R12, Ph, Cl, OAc, or Me; R10 is hydrogen, methyl, ethyl, propyl, or butyl; R11 is hydrogen, or methyl; and R12 is hydrogen, or methyl. Various polymer resins have the second repeating unit as an ether moiety including, but are not limited to, —(CH2)n—O—, —CH(Me)-CH2—O—, —CH2—CH(OH)—CH2—O—, —CH(CH2OH)—CH2—O—, —CH2—C(Me)2-CH2—O—, —CH2—C(CH2OH)2—CH2—O—, or combination thereof, wherein n=2, 3, 4, 5, or 6; and the resin further includes a third repeating unit, wherein the third repeating unit is —C(═NH)—Ar—C(═NH)—O—, —C(═O)—Ar—C(═O)—O—, —C(═O)—CH2—CH2—CH2—CH2—C(═O)—O—, or a combination thereof. In each of the above embodiments of the resin, the resin may be degradable upon a two-photon excitation of the chromophore.
The two-photon absorbing chromophore can be adapted to a variety of chemical structures. An example of a two-photon absorbing chromophore is 2,5-bis-(2-{4-[ethyl-(2-hydroxy-ethyl)-amino]-phenyl}-vinyl)-terephthalonitrile (VIII). Other two-photon absorbing chromophores can also be used. The hydroxyl moieties in the chromophore can be used to form step growth condensation type polymers such as, but not limited to, polyesters, polyethers, or polyurethanes.
In step growth polymerization, typically monomers with two functional groups are used. In
The two-photon absorbing chromophore 2,5-Bis-(2-{4-[ethyl-(2-hydroxy-ethyl)-amino]-phenyl}-vinyl)-terephthalonitrile (VIII) can form other monomers by replacing the hydroxyl moieties with functional moieties such as acrylic, styrenic, or vinylic moieties. Amine moieties can also be used to replace the hydroxyl moieties, which can then form polyamides or acrylamides. These functional two-photon absorbing chromophores can be used in chain growth systems such as ethylene, propylene, acrylic, styrene, vinyl acetates, vinyl chlorides and the like. Epoxy and urethane systems can be created by using glycidyl and isocyanates with the chromophore.
Some embodiments provide a polymer resin having a polymeric backbone, wherein at least portion of the backbone includes a two-photon absorbing chromophore. In some embodiments, the polymer resin has an equimolar quantity of a first repeating unit and a second repeating unit, wherein the first repeating unit has a two-photon absorbing chromophore in the polymeric backbone. In other embodiments, the first repeating unit is about 5%, about 3%, about 2%, about 1%, about 0.5%, about 0.2%, about 0.1%, about 0.05%, about 0.01%, and ranges between any two of these values including endpoints, as a molar percentage of the second repeating unit.
Some embodiments provide a recyclable material having a polymer resin with a polymeric backbone, the polymer resin having a first repeating unit and a second repeating unit, wherein the first repeating unit has a two-photon absorbing chromophore in the polymeric backbone. In various embodiments, the recyclable material is configured for use in packaging, coatings, electronic components, adhesives or a combination thereof.
Some embodiments of the various recyclable materials further include at least one binder selected from an alkyd resin, acrylic resin, vinyl-acrylic resin, vinyl acetate/ethylene resin, polyurethane resin, polyester resin, melamine resin, epoxy resin, an oil, polyether resin, novolac resin, nylon, polyamide resin, styrenic resin, polyimide resin, polyamide-imide resin, and combinations thereof.
The recyclable material may have a two-photon absorbing chromophore in the polymeric backbone, and two-photon absorbing chromophore described herein may be any two-photon chromophore known in the art. In some embodiments, the recyclable material may have a two-photon absorbing chromophore in the polymeric backbone having a moiety of Formula I. In some embodiments, the recyclable material may also have a two-photon absorbing chromophore in the polymeric backbone having a moiety of Formula II. In some embodiments, the recyclable material may also have a two-photon absorbing chromophore in the polymeric backbone having a moiety of Formula III. In some embodiments, the recyclable material may also have a two-photon absorbing chromophore in the polymeric backbone having a moiety of Formula IV. In some embodiments, the recyclable material may also have a two-photon absorbing chromophore in the polymeric backbone having a moiety of Formula V. In some embodiments, the recyclable material may have a two-photon absorbing chromophore in the polymeric backbone, the two-photon absorbing chromophore having one or more moieties represented by Formulae I-V, or any combinations thereof.
In various embodiments, the recyclable material may have the two-photon absorbing chromophore present in the polymer resin in an amount of not more than 2% by weight.
Various recyclable material may have the second repeating unit including, but is not limited to, —(CH2)n-O—, —CH(Me)-CH2—O—, —CH2—CH(OH)—CH2—O—, —CH(CH2OH)—CH2—O—, —CH2—C(Me)2-CH2—O—, —CH2—C(CH2OH)2—CH2—O—, or a combination thereof, wherein n=2-6; and the polymer resin further includes a third repeating unit, the third repeating unit including, but is not limited to, —C(═O)—Ar—C(═O)—O—, —C(═O)—CH2—CH2—CH2—CH2—C(═O)—O—, or a combination thereof.
Various embodiments of the recyclable materials may have the second repeating unit including, but is not limited to, —C(═O)—Ar—C(═O)—CH2—CH2—O—, —C(═O)—NH—Ar—CH2—Ar—NH—C(═O)—O—CH2—CH2—O—, —C(═O)—X3—NH—, or —C(═O)—X3—O—; wherein X3=—CH((C1-C6)alkyl)-, —(CH2)n-, —Ar—C(═O)—NH—Ar—, or —(CH2)n-C(═O)—NH—(CH2)m-C(═O)—, and wherein m=2, 3, 4, 5, or 6; and n=2, 3, 4, 5, or 6. In other embodiments, the recyclable material may have the second repeating unit including, but is not limited to, —(CH2)n-O—, —CH(Me)-CH2—O—, —CH2—CH(OH)—CH2—O—, —CH(CH2OH)—CH2—O—, —CH2—C(Me)2-CH2—O—, —CH2—C(CH2OH)2—CH2—O—, or combination thereof wherein n=2-6; and the polymer resin may further include a third repeating unit, wherein the third repeating unit is —C(═NH)—Ar—C(═NH)—O—. In still other embodiments, the recyclable material may have the second repeating unit including, but is not limited to, —R7—O—X4—O—R7—O—, wherein: R7 is —CH2—CHOH—CH2—; and X4 is —Ar—C(Me)2-Ar—, —Ar—C(CF3)2—Ar—, a novolac resin, a phenol novolac resin, a cresol novolac resin, -alkylidene-, or combination thereof. In the various embodiments, Ar may be a 1,4-phenylene. In other embodiments, Ar may be a 1,3-phenylene. In still other embodiments, Ar may be a 1,2-phenylene.
Various embodiments of the recyclable material may have a second repeating unit that includes —CH2—CR8R9—, wherein R8=H, or Me; R9=H, COOH, COOR10, CONR11R12, Ph, Cl, OAc, or Me; R10 is hydrogen, methyl, ethyl, propyl, or butyl; R11 is hydrogen, or methyl; and R12 is hydrogen, or methyl.
Each of the various embodiments of the recyclable material may degrade upon a two-photon excitation.
Disclosed are methods of preparing a polymer resin. The methods include polymerizing a first monomer and a second monomer, wherein the first monomer has a two-photon absorbing chromophore which is incorporated into a backbone of the polymer resin. Any suitable two-proton absorbing chromophore known in the art may be used. In some methods, the two-photon absorbing chromophore includes a moiety of Formula VI:
wherein A1 may be aryl, heteroaryl, substituted aryl, cycloalkyl, heterocycloalkyl, methine, vinyl, substituted vinyl, aryl group fused to the bonded C atom, or cyclic compound fused to the bonded C atom.
In some embodiments, A2 may be aryl, heteroaryl, substituted aryl, cycloalkyl, heterocycloalkyl, methine, vinyl, substituted vinyl, aryl group fused to the bonded C atom, or cyclic compound fused to the bonded C atom;
In some embodiments, R1 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H. R2 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H;
In some embodiments, R3 may be arylene, alkenylene, or a bivalent cyclic compound. R4 may be arylene, alkenylene, or a bivalent cyclic compound;
In some embodiments, X1 may be B, C, N, Si, O, P, S, Se, or As. X2 may be B, C, N, Si, O, P, S, Se, or As;
In some embodiments, R5 may be a hydrogen, an alkylene, a substituted alkylene, an unsaturated ester, an alkylene substituted —C(═O)-Ph, an alkylene oxide, or an acyl isocyanate;
In some embodiments, R6 may be a hydrogen, an alkylene, a substituted alkylene, an unsaturated ester, an alkylene substituted —C(═O)-Ph, an alkylene oxide, or an acyl isocyanate; and n is an integer from 1 to 20.
In some embodiments, R5 may be —H; —CH═CH2; —C(CH3)═CH2; —CO—CH═CH2; —CO—C(CH3)═CH2; —CO—C6H4—CH═CH2; —CO—C6H4—C(CH3)═CH2; —CH2—CH(CH2)O; —CO—CH2NCO; —C(Cl)═CH2; or —C(OAc)═CH2.
In some embodiments, R6 may be —H; —CH═CH2; —C(CH3)═CH2; —CO—CH═CH2; —CO—C(CH3)═CH2; —CO—C6H4—CH═CH2; —CO—C6H4—C(CH3)═CH2; —CH2—CH(CH2)O; —CO—CH2NCO; —C(Cl)═CH2; or —C(OAc)═CH2.
In some methods, the two-photon absorbing chromophore includes a moiety of Formula VII:
wherein R1 is —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H.
In some embodiments, R2 may be —H, —C≡N, —OH, —O-alkyl, —C(═O)—OMe, —NH-alkyl, —N═N-alkyl, —CH═N-alkyl, —SH, —S-alkyl, —S(═O)-alkyl, —SO2-alkyl, or —SO3H.
In some embodiments, R5 may be hydrogen; an alkylene; a substituted alkylene; an unsaturated ester; an alkylene substituted —C(═O)-Ph; an alkylene oxide; or an acyl isocyanate.
In some embodiments, R6 may be hydrogen; an alkylene; a substituted alkylene; an unsaturated ester; an alkylene substituted —C(═O)-Ph; an alkylene oxide; or an acyl isocyanate.
In some embodiments, X1 may be B, C, N, Si, O, P, S, Se, or As; and X2 is B, C, N, Si, O, P, S, Se, or As.
Exemplary two-photon absorbing chromophores of formula VII may include:
In various methods, R5 and R6 are hydrogen, and the second monomer includes ethylene glycol, 1,4-butanediol, 1,2-propanediol, 1,3-propanediol, propylene glycol, glycerol, neopentyl glycol, trimethylol propane, hexanediol, or a combination thereof, and the polymerizing step further includes polymerizing a third monomer with the first and second monomers, wherein the third monomer includes terephthalic acid, isophthalic acid, orthophthalic acid, phthalic anhydride, hexanedioic acid, or a combination thereof. In other methods, R5 and R6 are hydrogen, the second monomer contains terephthalic acid; and the polymerizing step further includes polymerizing a third monomer with the first and second monomers, wherein the third monomer includes ethylene glycol, 1,4-butanediol, 1,2-propanediol, 1,3-propanediol, glycerol, neopentyl glycol, trimethylol propane, or a combination thereof.
In various methods, the second monomer may include but is not limited to, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, epoxidized novolac, epoxy phenol novolac, epoxy cresol novolac, aliphatic diglycidyl ether, glycidylamine epoxide, or a combination thereof. In yet other methods, the second monomer includes, but is not limited to, polystyrene, polyethylene, polyvinyl, polyacrylate, poly(ethylene terephthalate), polyvinylchloride, polypropylene, polyvinyl acetate, polyester, polyamide, polyacrylamide, polyepoxide, polyurethane, or a combination thereof. In still another method, the second monomer includes, but is not limited to, styrene, ethylene, propylene, or a combination thereof; and R5 and R6 are independently selected from —CH═CH2; —C(CH3)═CH2; —CO—C6H4—CH═CH2; —CO—C6H4—C(CH3)═CH2; —C(Cl)═CH2; and —C(OAc)═CH2. In still other methods, the second monomer includes, but is not limited to, an acrylate, methacrylate, or a combination thereof; and R5 and R6 are independently selected from —CO—CH═CH2; —CO—C(CH3)═CH2; or a combination thereof. In yet other methods, the second monomer includes, but is not limited to, a diisocyanate; R5 and R6 are each —CO—CH2NCO; and the polymerizing further includes polymerizing a third monomer with the first and second monomers, wherein the third monomer includes ethylene glycol, 1,4-butanediol, 1,2-propanediol, 1,3-propanediol, glycerol, neopentyl glycol, trimethylol propane, or a combination thereof. In another method, the second monomer is diglycidyl ether; and R and R1 are each —CH2—CH(CH2)O. In yet another method, the second monomer includes, but is not limited to, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, epoxidized novolacs, epoxy phenol novolacs, epoxy cresol novolacs, aliphatic diglycidyl ethers, glycidylamine epoxides, or a combination thereof.
In any of the embodiments of the methods of preparing a polymer resin, the first monomer may be present in the resin in an amount of no more than 5% by weight. In other embodiments, the first monomer may be present in the resin in an amount of no more than 2% by weight. In still other embodiments, the first monomer may be present in the resin in an amount of no more than 1% by weight of the resin. In yet another embodiment, the first monomer may be present in the resin in an amount of no more than 0.5% by weight.
Also disclosed are methods of degrading a polymer, the methods include exposing the polymer to light, the polymer having a first repeating unit and a second repeating unit, wherein the first repeating unit has a two-photon absorbing chromophore in a polymeric backbone of the polymer. The two-photon absorbing chromophore disclosed herein may be any two-photon absorbing chromophore known in the art. In some embodiments, the two-photon absorbing chromophore has Formula I. In some embodiments, the two-photon absorbing chromophore has Formula II. In other embodiments, the two-photon absorbing chromophore has Formula III. In some embodiments, the two-photon absorbing chromophore has Formula IV. In some embodiments, the two-photon absorbing chromophore has Formula V. In some embodiments, the two-photon absorbing chromophore may be one or more structures represented by Formulae I-V, or any combinations thereof.
In the various methods, the resin may degrade upon a two-photon excitation. In some methods, exposing the polymer to light includes exposing the polymer to high-intensity light. In some embodiments, exposing the polymer to light includes exposing the polymer to a cross section of light from two lasers. In other embodiments, exposing the polymer to light includes exposing the polymer to light from a diode laser.
While lasers may be used for this process, excitation of 2-photon chromophores does not require elaborate and expensive lasers. Diode lasers are more than sufficient for the process.
These technologies and embodiments illustrating the method and materials used may be further understood by reference to the following non-limiting examples.
A solution of 1,4-dicyano-3,6-dimethylbenzene (21 grams, 0.13 mol) and Br2 (40 grams, 0.25 mol) in CCl4 (1.0 L) is irradiated with 400 W tungsten lamp for 12 hours. After removing the unreacted Br2 with Na2S2O3 (aq), the product is extracted with CH2Cl2 and purified on a silica column using hexane/ethyl acetate (30:1, by volume) as eluent to obtain yellow solid. Yield: 14 grams (34%).
A solution of 1,4-bis(bromomethyl)-3,6-dicyanobenzene (13 grams, 41 mmol) prepared above and P(OEt)3 (29 grams, 0.25 mol) in toluene (200 mL) is refluxed for 5 hours. The solvent is removed in vacuo and the product is purified on a silica column using ethyl acetate/methanol (10:1, by volume) as eluent to obtain yellow solid. Yield: 15 grams (85%).
To a cooled solution of 4-[ethyl-(2-hydroxy-ethyl)-amino]-benzaldehyde (0.49 mmol) in 20 mL of methylene chloride under the nitrogen, 1.5 mL of bromotrimethylsilane is added dropwise. The reaction mixture is stirred at −20° C. for 2.5 hours, and then neutralized with 50 mL of saturated aqueous sodium bicarbonate solution. The residue is partitioned between water and methylene chloride and extracted. The combined extracts are dried over sodium sulfate. The crude product is purified by column chromatography using ethyl acetate and hexane (3:2, by volume) to obtain the product (yield: 83%).
Lithium diisopropylamide (1.5 M, 12 mL) is slowly added to a stirred solution of above prepared 1,4-bis(diethoxyphosphorylmethyl)-3,6-dicyanobenzene (3.3 grams, 7.7 mmol) in THF (80 mL) at 0° C. After stirring the mixture for 30 minutes, a solution of benzaldehyde, 4-[[2-[[(1,1-dimethylethyl)dimethylsilyl]oxy]ethyl]-ethylamino]- (0.80 grams, 2.6 mmol) in THF (20 mL) is added slowly and stirred for 1 day. The solvent was evaporated and the product is purified on a silica column using hexane/ethyl acetate (2:3, by volume) as eluent.
The t-butyldimethylsilyl protecting groups from 2,5-Bis-(2-{4-[(tert-butyl-dimethyl-silanyloxyethyl)-ethyl-amino]-phenyl}-vinyl)-terephthalonitrile are removed by refluxing in acetone/H2O (95:5, by volume) containing 5 mmol % of CuCl2.2H2O to obtain compound VIII.
Synthesis of monomer 2,5-bis(4-(ethyl(2-(oxiran-2-ylmethoxy)ethyl)amino)-styryl)terephthalonitrile, (VIIIa) includes mixing compound VIII (1.35 grams, 2.7 mmol), 5 mL of dioxane, and 2 microliters of boron trifluoride ethyl etherate solution (45 weight % boron trifluoride), and heating the mixture to 65° C. Epichlorohydrin (0.6 grams) is added to the mixture. The mixture is stirred for an hour at 60-87° C. and sodium aluminate (0.1 grams) is added. The mixture is refluxed for about 8 hours, and then filtered. The filtrate is concentrated to yield the monomer VIIIa.
Synthesis of the monomer 2,5-bis(4-(ethyl(2-(vinyloxy)ethyl)amino)-styryl)terephthalonitrile, (VIIIb) includes mixing 20 mL of methylene chloride, 0.5 grams (7.14 mmoles) divinyl ether, compound VIII prepared as in Example 1 (1.8 grams, 3.6 mmol), and 0.1 grams red mercuric oxide. The mixture is stirred and trifluoroacetic acid (100 microliters) is added to the mixture as it is being stirred. The mixture is refluxed under a water cooled reflux condensor and desiccant drying tube. The methylene chloride solvent is removed in vacuo. The residue is dissolved in carbon tetrachloride and eluted with 35 mL of carbon tetrachloride through 2.5 grams neutral alumina (pH 7.3). The carbon tetrachloride is removed in vacuo to yield Monomer VIIIb.
Synthesis of the monomer 2,2′-(4,4′-(1E,1′E)-2,2′-(2,5-dicyano-1,4-phenylene)bis(ethene-2,1-diyl)bis(4,1-phenylene))bis(ethylazanediyl)bis(ethane-2,1-diyl) bis(4-vinylbenzoate) (VIIIc) includes mixing 4-vinybenzoyl chloride (1.0 grams, 6.3 mmol) in tetrahydrofuran (5 mL), and adding the mixture dropwise over 10 minutes to a mixture of compound VIII (1.35 grams, 2.7 mmol) prepared as in Example 1, triethylamine (0.55 grams, 5.4 mmol) and tetrahydrofuran (25 mL). The mixture is stirred at 20° C. for 21 hours. The mixture is poured into ice-cooled water (25 mL) and stirred for 3 hours. The tetrahydrofuran is removed in vacuo. Methylene chloride is added to the mixture form a separated layer of the chloride in the mixture. The methylene chloride phase is washed twice with dilute aqueous sodium bicarbonate (25 mL each) and once with saturated sodium chloride aqueous solution (25 mL). The methylene chloride phase is dried with sodium sulfate. The mixture is filtered and the solvents are removed in vacuo to obtain compound VIIIc.
Synthesis of 2,2′-(4,4′-(1E,1′E)-2,2′-(2,5-dicyano-1,4-phenylene)bis(ethene-2,1-diyl)bis(4,1-phenylene))bis(ethylazanediyl)bis(ethane-2,1-diyl) bis(2-methylacrylate) (VIIId) includes mixing methacrylic anhydride (0.91 grams, 6.3 mmol) in anhydrous tetrahydrofuran (5 mL) and adding the mixture dropwise over 10 minutes to a mixture of compound VIII (1.35 grams, 2.7 mmol) prepared as in Example 1, triethylamine (1.00 grams, 9.9 mmol), and tetrahydrofuran (25 mL). The mixture is stirred at 20° C. for 21 hours. The mixture is poured into ice-cooled water (25 mL). The mixture is stirred for 3 hours. The tetrahydrofuran is removed in vacuo. Methylene chloride is added to the mixture (3×50 mL), shaken vigorously, and forms a separated layer of the methylene chloride in the mixture. The methylene chloride phase is washed twice with dilute aqueous sodium bicarbonate (25 mL each) and once with saturated sodium chloride aqueous solution (25 mL). The methylene chloride phase is dried with sodium sulfate. The resulting solids are loaded onto a packed silica column and chromatographed using ethyl acetate:hexane (3:1, by volume). The solvents are removed in vacuo to obtain compound VIIId.
Synthesis of the monomer 2,2′-(4,4′-(1E,1′E)-2,2′-(2,5-dicyano-1,4-phenylene)bis(ethene-2,1-diyl)bis(4,1-phenylene))bis(ethylazanediyl)bis(ethane-2,1-diyl) bis(2-isocyanatoacetate) (VIIIe) includes the following: 1.47 mL of compound VIII (4.0 grams, 7.5 mmoles) prepared as in Example 1, dimethylaniline (2.12 mL, 2.02 grams, 16.7 mmoles), and diethyl ether are mixed, and the mixture is heated to reflux. Acetyl chloride (1.13 mL, 1.24 grams, 15.8 mmoles) is added to the mixture. The mixture is heated for an hour. The mixture is cooled to 20° C. Water (approximately 2 mL) is added to the mixture. The mixture is stirred until the solid materials dissolve. An ether layer is separated from the mixture and extracted with cold 10% sulfuric acid. The ether layer is washed with a saturated sodium bicarbonate solution. The ether solution is dried with anhydrous sodium sulfate. The solvents are removed in vacuo to yield a chloroacetate 2,2′-(4,4′-(1E,1′E)-2,2′-(2,5-dicyano-1,4-phenylene)bis(ethene-2, 1-diyl)bis(4,1-phenylene))bis(ethyl-azanediyl)bis(ethane-2,1-diyl) bis(2-chloroacetate).
Sodium azide and acetone are added to the chloroacetate prepared above. The mixture is heated and the acetone is distilled from the mixture. Water is added and the aqueous layer is extracted with ether. The ether solvents are removed in vacuo to obtain an azidoacetate 2,2′-(4,4′-(1E,1′E)-2,2′-(2,5-dicyano-1,4-phenylene)bis(ethene-2,1-diyl)bis(4,1-phenylene))bis(ethylazanediyl)bis(ethane-2,1-diyl) bis(2-azidoacetate).
The azidoacetate is mixed in methanol, and is reduced with 5 weight % palladium on charcoal catalyst and hydrogen gas. The hydrogen gas is displaced with nitrogen. The catalyst is removed by filtration. The catalyst is washed with methanol and the methanol combined with the reduced aminoacetate in methanol. The combined methanols are dried with sodium sulfite. The methanol solution is concentrated in vacuo to obtain an aminoacetate 2,2′-(4,4′-(1E,1′E)-2,2′-(2,5-dicyano-1,4-phenylene)bis(ethene-2,1-diyl)bis(4,1-phenylene))bis(ethyl-azanediyl)bis-(ethane-2,1-diyl) bis(2-aminoacetate).
The aminoacetate is converted to an isocyanate by reacting with thionyl chloride to yield the N-sulfinylacetate. The N-sulfinyl acetate is reacted with phosgene to yield the monomer VIIIe 2,2′-(4,4′-(1E,1′E)-2,2′-(2,5-dicyano-1,4-phenylene)bis(ethene-2,1-diyl)bis(4,1-phenylene))bis (ethyl-azane-diyl)bis(ethane-2,1-diyl) bis(2-isocyanatoacetate).
Terephthalic acid (one hundred parts), ethylene glycol (99 parts), and compound VIII (1 part) prepared as in Example 1, cobalt chloride (0.02 part), phosphorous acid (0.04 part), and antimony oxide (0.02 part) are mixed. The mixture is heated at atmospheric pressure, and then under high pressure to obtain a polyethylene terephthalate (PET)-based degradable plastic. The reaction sequence is illustrated as
1,4-Butanediol (0.3 grams, 3.5 mmol) and boron trifluoride etherate (0.5 grams, 3.5 mmol) are mixed at 20° C. under nitrogen for 2 hours. Ether is removed in vacuo at 0.1 mmHg vacuum at 20° C. for 5 hours to give 0.5 grams of the boron trifluoride etherate complex of 1,4 butanediol. Methylene chloride (2 mL) is added. The mixture is added dropwise over a 4 hour period at 0° C. to a solution of glycidyl ethyl ether (102 grams, 1 mole) and monomer VIIIa (0.6 grams, 1 mmole) from Example 2, in methylene chloride (100 mL). The mixture is stirred at 20° C. for 20 hours. The mixture is diluted with methylene chloride (100 mL), washed with saturated sodium bicarbonate, washed with water, and dried over magnesium sulfate. The solvents are removed in vacuo to obtain the poly(glycidyl ethyl ether) degradable plastic.
A mixture of montmorillonite (3.0 mg) and toluene (30 grams) under nitrogen atmosphere is heated to 45° C. The mixture is added dropwise at 45° C. over a one hour period to a solution of ethyl vinyl ether (36 grams, 0.5 mole) that is 0.7 weight % of water, and monomer VIIIb (0.6 grams, 1 mmole) prepared as in Example 3. The mixture is heated at 60° C. for one hour. The mixture is cooled to 20° C. Triethylamine (10 microliters) is added. The solvents are removed in vacuo to obtain the polyvinyl ethyl ether degradable plastic.
Equimolar amounts of monosodium citrate and sodium bicarbonate encapsulated in vegetable oil (54.8% of the batch), 30.5% of poly alpha methyl styrene, 12.0% of styrene-ethylene/butylene-styrene block copolymer, 7.5% of white mineral oil, 0.2% silica, and monomer VIIIc (0.5% by weight) prepared as in Example 4, are fed continuously into a mixer resulting in a masterbatch mix. The masterbatch is extruded. The extrudate is melted at a temperature of 150° C. Liquid carbon dioxide is injected as a blowing agent. The resulting mixture is extracted. The mixture is cooled and dried to obtain polystyrene degradable plastic as a foam sheet.
Methyl methacrylate (47 grams), toluene (700 mL), monomer VIIId (0.25 grams) prepared as in Example 5, and 1.91 grams of ethyl α-lithioisobutyrate are mixed and stirred 1 hour. The polymerization is stopped by adding 25 mL of methanol. The crude polymer is precipitated by the addition of hexane. The polymer is reprecipitated from toluene into hexane twice. The polymer is washed with water to remove alkaline initiator residue. The polymer is dried to a constant weight in vacuo to obtain the polymethacrylate degradable plastic.
4,4-Methylenebis(cyclohexyl isocyanate) (396 parts) is mixed with monomer VIIIe (3 parts) prepared as in Example 6. The mixture is heated with 4,4-methylene bis(aniline) at a ratio of 1.0 isocyanate groups to 0.98 amino groups, at 135° C. for 9 hours to obtain the polyisocyanate degradable plastic.
Two-photon induced degradation and complete erosion of photodegradable plastics and packaging materials are performed. Poly(ethylene terephthalate) (PET)-based photodegradable plastics are obtained from Example 7 (
It should be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments disclosed, the preferred methods, devices, and materials are now described.
The term “alkyl” or “alkyl group” refers to a branched or unbranched hydrocarbon or group of 1 to 20 carbon atoms, such as but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, octyl, decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl and the like. “Cycloalkyl” or “cycloalkyl groups” are branched or unbranched hydrocarbons in which all or some of the carbons are arranged in a ring, such as but not limited to cyclopentyl, cyclohexyl, methylcyclohexyl and the like. The term “lower alkyl” includes an alkyl group of 1 to 10 carbon atoms.
The term “aryl” or “aryl group” refers to monovalent aromatic hydrocarbon radicals or groups consisting of one or more fused rings in which at least one ring is aromatic in nature. Aryls may include but are not limited to phenyl, napthyl, biphenyl ring systems and the like.
Although the present technology has been described in considerable detail with reference to certain preferred embodiments thereof, other versions are possible. Therefore the spirit and scope of the appended claims should not be limited to the description and the preferred versions contained within this specification.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2013/053988 | 8/7/2013 | WO | 00 |
