Method of post-consumer pet polyester depolymerization and repolymerization

Abstract

Disclosed herein are processes for hydrolytically depolymerizing post-consumer polyethylene terephthalate (PET) mixed polyester plastics, without the need of a catalytic material, into a depolymerized-polyester product including one or more of a depolymerized-polyester monomer product, a depolymerized-polyester oligomer product or a mixture thereof. The present disclosure also relates to processes polymerizing the depolymerized-polyester product into renewable polymers and processes for creating blended copolymers. Compositions containing the depolymerized-polyester products, the renewable copolymers and / or the blended copolymers are also disclosed.

Description

[0001]METHOD OF POST-CONSUMER PET POLYESTER DEPOLYMERIZATION AND REPOLYMERIZATION CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to U.S. Provisional Patent Application No.63 / 534,449, filed on August 24, 2023, and the contents of which are incorporated herein by reference in their entireties for all purposes. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH This invention was made with government support under Grant No. DE-SC0020939 awarded by the Department of Energy. The Government has certain rights in the invention. FIELD The present disclosure relates to processes for hydrolytically depolymerizing post- consumer polyethylene terephthalate (PET) mixed polyester plastics, without the need of a catalytic material, into a depolymerized-polyester product including one or more of a depolymerized-polyester monomer product, a depolymerized-polyester oligomer product or a mixture thereof. The present disclosure also relates to methods of polymerizing the depolymerized-polyester product into renewable polymers. BACKGROUND PET plastics are currently produced by polymerization of petroleum-derived terephthalic acid (TPA) and ethylene glycol (EG). This process currently produces over 35 million tons of PET and other polyester plastics. The majority of these plastics are discarded to the environment as a waste after the end-use of the final plastic made consumer goods, e.g., water bottles, soft drink containers, fibers, textiles, etc. Uncontrolled and unregulated release of this waste, which is non-degradable, creates environmental hazards. Waste mixed plastics are currently sorted and polyester fraction, for example PET plastic, is currently recycled through mechanical processing, which has the following disadvantages: (i) it causes a significant loss in the properties of plastics (lower ductility, diminished molecular weight and reduced mechanical strength) and the recycled plastics are shredded, melted and molded into lower value products for packaging, building, construction and other applications, which is often referred to as "carbon downcycling"; and (ii) because the material properties of used plastics have already been degraded when recycled to produce lower value products, the later materials cannot be recycled again upon their use and are hence discarded. In contrast to the mechanical processing methods discussed above, selective depolymerization or breakdown of post-consumer PET into PET’s building block chemicals and the repolymerization of the building blocks can produce renewable PET with similar qualities and properties as virgin PET. Chemical breakdown of waste PET plastic via alcoholysis, glycolysis, hydrolysis, methanolysis, aminolysis and other methods have been reported. For example, a small percentage of post-consumer PET is commercially broken down by glycolysis and methanolysis processes. These processes utilize petroleum-derived solvents, such as ethylene glycol, by employing reasonably high temperatures (>200 °C). Additionally, the separation of the derived product by crystallization is energy-intensive. Thus, to address the foregoing issues, we disclose herein a new depolymerization process for post-consumer PET mixed polyester plastics that can operate in an environmentally benign solvent without using a petroleum-derived solvent and can operate without using a catalytic material to minimize emissions and avoid catalyst residue separation complexity from the depolymerized product. SUMMARY Disclosed herein is a process for depolymerizing a polyester including (i.e., comprising) one or more of the following steps: (i) contacting the polyester with water to form a reaction mixture; and (ii) heating the reaction mixture to at least 150 °C for a set amount of time to depolymerize at least a portion of the polyester to a depolymerized-polyester product, wherein the depolymerized-polyester product includes one or more of a depolymerized-polyester monomer product and / or a depolymerized-polyester oligomer product. Disclosed herein is also a composition including one or more of the depolymerized- polyester products produced from any one of the depolymerization methods disclosed herein. Also disclosed herein is a process for producing renewable polyester including one or more of the following steps: (i) contacting the depolymerized-polyester product prepared according to any one of the depolymerization methods disclosed herein with a catalyst and, optionally, an alkylene glycol to form a polymerization feed mixture, wherein the depolymerized-polyester product includes one or more of a depolymerized-polyester monomer product and / or a depolymerized-polyester oligomer product; (ii) polymerizing the polymerization feed mixture by esterification and subsequent polycondensation at a temperature of at least 100 °C, optionally in the presence of an inert gas, to produce a post- polymerization product mixture containing the renewable polyester; and (iii) removing a residual volatile organic compound, optionally in the presence of the inert gas, from the post- polymerization product mixture. Also disclosed herein is a process for producing a renewable copolymer including one or more of the following steps: (i) contacting a depolymerized-polyester product prepared according to any one of the depolymerization methods disclosed herein, or an un- depolymerized polyester, with a comonomer and, optionally, alkylene glycol to form a copolymerization feed mixture, wherein the comonomer includes either a caprolactone, a caprolactone-based oligomer, a caprolactone-based polymer, or a mixture thereof; (ii) heating the copolymerization feed mixture to at least about 150°C in the presence of a ring opening polymerization catalyst and a second catalyst to form a post-copolymerization product mixture containing the renewable copolymer; and (iii) removing one or more copolymer-residual volatile organic compounds, optionally in the presence of an inert gas, from the post- copolymerization product mixture, wherein the one or more copolymer-residual volatile organic compounds include a caprolactone, a caprolactone-based oligomer, the optional alkylene glycol, or mixtures thereof. Disclosed herein is also a process for creating a blended copolymer, the process including one or more of: blending an un-depolymerized polyester and any renewable copolymer prepared according to any one of the processes disclosed herein to create a blending feed mixture; and heating the blending feed mixture under stirring at a temperature in the range of about 150 °C to about 300 °C for a blending time in the range of about 15 minutes to about 20 hours to create the blended copolymer. BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the compositions and processes disclosed herein will be apparent to those skilled in the art reading the following detailed description in conjugation with the exemplary embodiments illustrated in the drawings, wherein: FIG. 1 depicts an image of an exemplary dried oligomer product obtained by an exemplary PET depolymerization process that was performed in water at 160 °C for 18 hours in a mechanical stirrer spinning at 1300 RPM. FIG. 2 depicts the average molecular weight (MW) of oligomers fractions from an exemplary depolymerized polyester product as a function of depolymerization time. The average MW was calculated from measured MW of different fractions of oligomers in the depolymerized product from gel permeation chromatography (GPC) data shown in Table 1. Reaction conditions: PET to water weight ratio = 6.5; reaction temperature = 160 °C; reaction time varied from 10 hours to 21 hours and reactor’s mechanical stirrer speed = 1300 RPM. FIG.3 depicts a HPLC chromatogram of an exemplary depolymerized solid monomer, terephthalic acid (TPA). Retention time of peak matched with standard commercial TPA. FIG. 4 depicts a NMR spectrum of an exemplary depolymerized solid monomer, terephthalic acid (TPA). The resonance of peaks matched with standard commercial TPA. FIG.5 depicts a change in acid numbers for an exemplary depolymerized TPA product as a function of PET polyester depolymerization reaction time. Reaction conditions: 200 °C, 900 RPM, water to PET mass ratio =10. FIG. 6 depicts a HPLC of an exemplary PET depolymerized ethylene glycol (EG) product using a refractive index (RI) detector. FIG.7 depicts a HPLC of a standard commercial EG product at different concentrations using a RI detector. FIG.8 depicts concentrations of an exemplary depolymerized EG product as a function of PET polyester depolymerization reaction time. Reaction conditions: 200 °C, 900 RPM, water to PET mass ratio =10. FIG. 9 depicts a comparison between an exemplary depolymerized EG's appearance with that of a commercial EG's appearance. FIG. 10 depicts a HPLC of an exemplary distilled depolymerized EG product using a RI detector. DEG is diethylene glycol. FIG. 11 depicts a PET sample from standard bis-hydroxy ethylene terephthalate (BHET) (a) and an exemplary renewable PET sample obtained from a depolymerized oligomer product (b). The right image shows the renewable PET sample after palletization. FIG.12 depicts a GPC spectra of a synthesized exemplary renewable PET. FIG. 13 depicts a DSC plot of an exemplary, as-synthesized renewable PET from a depolymerized oligomer product. FIG. 14 depicts a DSC plot of an exemplary adhesive copolymer synthesized from a depolymerized oligomer and caprolactone. FIG. 15 depicts a GPC plot of an exemplary adhesive copolymer synthesized from a depolymerized oligomer and caprolactone. FIG. 16 depicts a DSC plot of an exemplary adhesive copolymer synthesized by blending of a PET flake with a polymer. DETAILED DESCRIPTION All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. One aspect of the present disclosure is a process for depolymerizing a polyester including one or more of the following steps: (i) contacting the polyester with water to form a reaction mixture; and (ii) heating the reaction mixture to at least 100 °C for a set amount of time to depolymerize at least a portion of the polyester to a depolymerized-polyester product, wherein the depolymerized-polyester product includes one or more of a depolymerized- polyester monomer product and / or a depolymerized-polyester oligomer product. In exemplary embodiments, the polyester used in the depolymerization process includes at least one or more of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polybutylene adipate terephthalate, polyethylene furanoate, polytrimethylene furanoate, polybutylene furanoate, polycarbonate, polyglycolic acid, polylactic acid, poly-2-hydroxy butyrate, polyhydroxyalkanoate, poly(3-hydroxybutyrate-co- 3-hydroxyvalerate), polycaprolactone, polybutylene succinate and / or any combination thereof. In exemplary embodiments, the polyester used in the process includes one or more of a clear polyethylene terephthalate, a colored polyethylene terephthalate, mixed polyethylene terephthalate, and / or any mixtures thereof. In exemplary embodiments, the polyester used in the depolymerization process includes one or more of a clear ocean-borne polyethylene terephthalate, a colored ocean-borne polyethylene terephthalate, a mixed ocean-borne polyethylene terephthalate, a clear river- borne polyethylene terephthalate, a colored river-borne polyethylene terephthalate, a mixed river-borne polyethylene terephthalate, a clear lake-borne polyethylene terephthalate, a colored lake-borne polyethylene terephthalate, a mixed lake-borne polyethylene terephthalate, a clear landfill-borne polyethylene terephthalate, a colored landfill-borne polyethylene terephthalate, a mixed landfill-borne polyethylene terephthalate and / or any mixture thereof. As used herein, the term “ocean-borne PET” refers to PET recovered from an ocean; the term “river-borne PET” refers to PET recovered from a river; the term “lake-borne PET” refers to PET recovered from a lake; and the term “landfill-borne PET” refers to PET recovered from a landfill. The PET recovered from an ocean, a lake, a river, or a landfill can be in any suitable form, including but not limited to, a PET bottle, a PET film, a PET fiber, a PET fabric, a PET flexible packaging, a PET substrate, a PET article containing a metal layer, or mixtures thereof. As used herein the term “mixed PET” refers to any PET containing other materials, such as a polymer other than PET, a metal, an inorganic material, etc. For example, a mixed PET can refer to multilayer packaging, such as specialty bottles where PET sandwiches additional layers, such as PVOH, to reduce oxygen permeability; PET packaging with a cap, lid, and / or label formed of different polymers; PET used in tape applications, such as the carrier for magnetic tape or backing for pressure-sensitive adhesive tapes; PET used as a substrate in thin film devices, such as a solar cell; and / or PET films including a thin layer of metal, such as Mylar®. As used herein the term “colored PET” refers to any PET including a colorant, thereby resulting in the PET having a colored or opaque-colored hue. In exemplary embodiments, the polyester used in the depolymerization process is a clear or transparent PET containing no colorant. In other exemplary embodiments, the polyester used in the depolymerization process is a clear or transparent PET having a transmittance of at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% according to the standard ASTM D1003 / ISO 13468, and / or a haze (turbidity or cloudiness) of less than 40%, less than 30%, less than 15%, less than 10%, or less than 5%, according to the standard ASTM D1003 / ISO / DIS 14782. In exemplary embodiments, the polyester used in the depolymerization process is in the form of and / or derived from a PET bottle, a PET film, a PET fiber, a PET fabric, a PET flexible packaging, a PET substrate, a PET article containing a metal layer, or any mixtures thereof. In exemplary embodiments, the polyester used in the depolymerization process is in particulate form or flake form. The particulate form or flake form of the polyester can have an average particle size in a range of from about 5 µm to about 100 mm, about 10 µm to 90 mm, about 50 µm to 50 mm, about 100 µm to 1 mm, or any specific average particle size or range of average particle sizes falling within the above ranges. In exemplary embodiments, the polyester is coarsely ground into flakes or particulates. The polyester flakes can have an average size of about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 7.5 cm, about 8 cm, about 9 cm, about 10 cm, about 15 cm, about 25 cm, or about 50 cm. The polyester flake can have any suitable shape, such as irregular, rectangular, square, round, oval, etc. In exemplary embodiments, the polyester flakes have an average size of about 3 cm x about 3 cm, about 2 cm x about 2 cm, or about 1 cm x about 1 cm. In other exemplary embodiments, the polyester is in a particulate form that has an average particle size in a range of from about 2 µm, about 3 µm, about 4 µm, about 5 µm to about 100 mm, about 50 mm, about 25 mm, about 20 mm, about 10 mm, about 5 mm, or about 1 mm. When an amount, concentration, or other value or parameter in the present disclosure is given as either a range, a preferred range or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range. Accordingly, it should be understood that any description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. The description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, a description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. As used herein, the term "about" refers to a value that is ± 5% of the stated value. In addition, it is understood that reference to a range of a first value to a second value includes the range of the stated values, e.g., a range of about 1 to about 5 also includes the more precise range of 1 to 5. It is also understood that the ranges disclosed herein include any selected subrange within the stated range, e.g., a subrange of about 50 to about 60 is contemplated in a disclosed range of about 1 to about 100. Any suitable polyester can be depolymerized by the disclosed process. Exemplary polyesters include, but are not limited to, polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, polybutylene adipate terephthalate, polyethylene furanoate, polytrimethylene furanoate, polybutylene furanoate, polycarbonate, polyglycolic acid, polylactic acid, poly-2-hydroxy butyrate, polyhydroxyalkanoate, poly(3- hydroxybutyrate-co-3-hydroxyvalerate), polycaprolactone, polybutylene succinate, and mixtures thereof. In exemplary embodiments, the step of heating the reaction mixture is carried out / performed at a temperature range of from about 100 °C to about 300 °C, from about 120 °C to about 300 °C, from about 150 °C to about 300 °C, from about 100 °C to about 250 °C, from about 160 °C to about 200 °C or any specific temperature or temperature range falling within the above ranges. In exemplary embodiments, the step of heating the reaction mixture is carried out / performed for about 1 hour to about 35 hours, about 1 hour to about 30 hours, about 2 hours to about 30 hours, about 4 hours to about 24 hours, about 5 hours to about 12 hours or any specific amount of time or range of times falling within the above ranges. In exemplary embodiments, the process for depolymerizing the polyester forms a depolymerized-polyester product that contains a depolymerized-polyester oligomer product including one or more oligomers having a molecular weight of greater than 166 Da, greater than 200 Da, a molecular weight of about 166 to about 9000 Da, a molecular weight from about 166 Da to about 10000 Da or any specific molecular weight or range of molecular weights falling within the above range. In exemplary embodiments, the process for depolymerizing the polyester forms a depolymerized-polyester product that contains a depolymerized-polyester monomer product including one or more monomers having a molecular weight of greater than 62 Da, a molecular weight from about 62 Da to about 166 Da or any specific molecular weight or range of molecular weights falling within the above range. In exemplary embodiments, the process for depolymerizing the polyester includes depolymerizing PET to form a depolymerized-polyester product containing one or more of a depolymerized-PET monomer product, a depolymerized-PET oligomer product or a mixture thereof. The depolymerized-PET monomer product can include ethylene glycol and / or terephthalic acid. The depolymerized-PET oligomer product can include one or more oligomers of PET. In exemplary embodiments, the one or more oligomers can have a molecular weight of greater than or equal to about 150 Da, about 166 Da, about 200 Da, about 210 Da, about 254 Da, about 338 Da, about 506 Da, about 639 Da, about 789 Da, about 933 Da, about 977 Da, about 1500 Da, about 2000 Da, about 2500 Da, about 3000 Da, about 3500 Da, about 5000 Da, about 10000 Da, less than about 10000 Da, less than about 3700 Da, less than about 3000 Da, less than about 2700 Da, less than about 1500 Da, less than about 1200 Da, less than about 1000 Da, less than about 750 Da or less than about 166 Da. In exemplary embodiments, the one or more oligomers have a molecular weight of about 166 Da to about 3000 Da. In exemplary embodiments, the process for depolymerizing the polyester does not include or involve mixing any catalytic materials in the water solvent during polyester depolymerization process. As used herein, a "catalytic material" is any substance that increases the rate of a reaction (e.g., the depolymerization reactions disclosed herein) without itself being consumed. Examples of catalytic materials that can be excluded from the depolymerization reactions include, but are not limited to, any one of the catalysts disclosed herein. Another aspect of the present disclosure is a composition including one or more of the depolymerized-polyester products produced from any of the depolymerization methods disclosed herein. The composition can include one or more of the depolymerized-polyester products in concentrations, based on the total weight of the composition, ranging from about 0.1 wt% to 99.9 wt%, 5 wt% to 50 wt%, 10 wt% to 25 wt% or any specific weight percentage or range of weight percentages falling within the above ranges. Another aspect of the present disclosure is a process for producing a renewable polyester including one or more of the following steps: (i) contacting the depolymerized- polyester product prepared according to any one of the depolymerization methods disclosed herein with a catalyst and, optionally, an alkylene glycol to form a polymerization feed mixture, wherein the depolymerized-polyester product includes one or more of a depolymerized- polyester monomer product and / or a depolymerized-polyester oligomer product; (ii) polymerizing the polymerization feed mixture by esterification and subsequent polycondensation at a temperature of at least 100 °C, optionally in the presence of an inert gas, to produce a post-polymerization product mixture containing the renewable polyester; and (iii) removing a residual volatile organic compound, optionally in the presence of the inert gas, from the post-polymerization product mixture. As used herein, the term “renewable polyester” refers to a polyester including recycled post-consumer polyester. The renewable polyester can include any suitable amount of the recycled post-consumer polyester, such as for example at least 50 wt%, 55 wt%, 60 wt%, or 80 wt% or 90 wt%, or 100 wt%. Hence, for example, the term “renewable polyethylene terephthalate (PET)” refers to a polyester made from any suitable amount of recycled post- consumer PET, such as that obtained from clear ocean-borne polyethylene terephthalate, colored ocean-borne polyethylene terephthalate, mixed ocean-borne polyethylene terephthalate, clear river-borne polyethylene terephthalate, colored river-borne polyethylene terephthalate, mixed river-borne polyethylene terephthalate, clear lake-borne polyethylene terephthalate, colored lake-borne polyethylene terephthalate, mixed lake-borne polyethylene terephthalate, clear landfill-borne polyethylene terephthalate, colored landfill-borne polyethylene terephthalate, mixed landfill-borne polyethylene terephthalate or mixtures thereof. Any suitable inert gas can be used in the process for producing the renewable polyester, including, but not limited to, nitrogen, argon, and / or helium. In exemplary embodiments, the residual volatile organic compound removed from the post-polymerization product mixture includes one or more of depolymerized-polyester monomers and / or the optional alkylene glycol. In exemplary embodiments, the polymerization feed mixture formed from the polymerization step includes from about 30 wt% to about 99 wt% or about 30 wt% to about 95 wt% of depolymerized-polyester product(s), optionally from about 5 wt% to about 70 wt% of alkylene glycol and / or less than 0.4 wt% by weight of the catalyst, based on the total weight of the polymerization feed mixture. The depolymerized-polyester product(s), optional alkylene glycol, and catalyst can be present in the polymerization feed mixture in any specific wt% or range of wt% falling within their above respective ranges. In exemplary embodiments, the polymerization feed mixture formed from the polymerization step includes greater than about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, less than about 70 wt%, less than about 75 wt%, less than about 80 wt%, less than about 95 wt% or less than about 99 wt% by weight of the depolymerized-polyester product(s); and / or less than about 0.5 wt%, less than about 0.4 wt%, less than about 0.3 wt%, greater than about 0.05 wt%, greater than about 0.1 wt%, or greater than about 0.2 wt% by weight of the catalyst, based on the total amount of the polymerization feed mixture. In exemplary embodiments, the catalyst used in the contacting step of the process for producing a renewable polyester includes antimony (III) oxide, tin (II) octoate, titanium (IV) butoxide, germanium oxide, zinc acetate, or mixtures thereof. In exemplary embodiments, the polymerizing step of the process for producing the renewable polyester is carried out under an inert gas. In exemplary embodiments, the polymerizing step of the process for producing the renewable polyester is carried out at a temperature in a range of from about 100 °C to about 350 °C, or from about 200 °C to about 320 °C or any specific temperature or range of temperatures falling within the above ranges. In exemplary embodiments, the polymerizing step of the process for producing the renewable polyester is carried out for about 15 minutes to about 20 hours, for about 15 minutes to about 13 hours, for about 30 minutes to about 12 hours, about 1 hour to about 20 hours, for about 1 hour to about 8 hours, for about 2 hours to about 6 hours, or any specific amount of time or range of times falling within the above ranges. In exemplary embodiments, the process for producing the renewable polyester includes heating the polymerization feed mixture stage-wise; wherein during a first stage the polymerization feed mixture is heated from about 15 minutes to about 7 hours or from about 1 hour to about 4 hours at a temperature of from about 100 °C to about 320 °C, and wherein during a subsequent second stage the polymerization feed mixture is heated from about 15 minutes to about 13 hours or about 1 hour to about 10 hours at a temperature of from about 250 °C to about 350 °C or about 200 °C to about 350 °C. The time and temperature that the first stage and second stage of the heating step can be carried out at can include any specific time point or temperature and / or any range of timepoints or temperatures falling within the above ranges. In exemplary embodiments, the step of removing the residual volatile organic compound in the process for producing the renewable polyester is carried out under vacuum. In exemplary embodiments, the polymerizing step of the process for producing the renewable polyester is carried out under vacuum for in situ removal of the residual volatile organic compound. In exemplary embodiments, the renewable polyester is a renewable polyethylene terephthalate. In exemplary embodiments, the optional alkylene glycol in the contacting step of the process for producing the renewable polyester is ethylene glycol. In exemplary embodiments, the renewable polyester has a glass transition temperature in the range from about 15 °C to about 95°C, from about 40°C to about 95°C, from about 40°C to about 85°C, from about 50°C to about 80°C, from about 15 °C to about 80 °C, or any specific glass transition temperature or range of glass transition temperatures falling within the above ranges. In exemplary embodiments, the renewable polyester has an intrinsic viscosity in the range from about 0.1 dL / g to about 0.8 dL / g, about 0.4 dL / g to about 0.8 dL / g, 0.4 dL / g to about 0.7 dL / g or any specific intrinsic viscosity or range of intrinsic viscosities falling within the above ranges. Another aspect of the present disclosure is a process for producing a renewable copolymer including one or more of the following steps: (i) contacting a depolymerized- polyester product prepared according to any one of the depolymerization methods disclosed herein, or an un-depolymerized polyester (e.g., EXAMPLE 5), with a comonomer and, optionally, alkylene glycol to form a copolymerization feed mixture, wherein the comonomer includes either a caprolactone, a caprolactone-based oligomer, a caprolactone-based polymer, or a mixture thereof; (ii) heating the copolymerization feed mixture to at least about 150°C in the presence of a ring opening polymerization catalyst and a second catalyst to form a post- copolymerization product mixture containing the renewable copolymer; and (iii) removing one or more copolymer-residual volatile organic compounds, optionally in the presence of an inert gas, from the post-copolymerization product mixture, wherein the one or more copolymer- residual volatile organic compounds include a caprolactone, a caprolactone-based oligomer, the optional alkylene glycol, or mixtures thereof. Any suitable inert gas can be used in the process for producing the renewable copolymer, including, but not limited to, nitrogen, argon, and / or helium. In exemplary embodiments, the copolymerization feed mixture includes from about 0.1 wt% to about 95 wt% of a depolymerized-polyester product, from about 10 wt% to about 90 wt% of the comonomer, optionally from about 0 wt% to about 20 wt% of the optional alkylene glycol, less than about 2 wt% of the second catalyst, and less than about 2 wt% of the ring opening polymerization catalyst, wherein all wt% are based on the total amount of the copolymerization feed mixture. The depolymerized-polyester product, comonomer, optional alkylene glycol, second catalyst and ring opening polymerization catalyst can be present in the copolymerization feed mixture in any specific wt% or range of wt% falling within their above respective ranges. In exemplary embodiments, the copolymerization feed mixture includes greater than about 0.1 wt%, greater than about 10 wt%, greater than about 25 wt%, greater than about 50 wt%, greater than about 80 wt%, about greater than 90%, or less than about 95 wt% of the depolymerized-polyester oligomer product; from about 10 wt% to about 90 wt%, greater than about 10 wt%, greater than about 15 wt%, greater than about 20 wt%, less than about 50 wt%, less than about 75 wt%, or less than about 90 wt% of the comonomer; 0 wt%, about 0.1 wt%, about 1 wt%, less than about 5 wt%, less than about 10 wt%, or less than about 20 wt% of the optional alkylene glycol; less than about 2 wt%, less than about 1.5 wt%, less than about 1.0 wt%, greater than about 0.05 wt%, greater than about 0.1 wt%, or greater than about 0.5 wt% of the second catalyst; and / or less than about 2 wt%, less than about 1.5 wt%, less than about 1.0 wt%, greater than about 0.05 wt%, greater than about 0.1 wt%, greater than about 0.5 wt% of the ring opening polymerization catalyst, wherein all wt% are based on the total weight of the copolymerization feed mixture. In exemplary embodiments, the copolymerization feed mixture includes greater than about 0.1 wt%, greater than about 10 wt%, greater than about 25 wt%, greater than about 50 wt%, or less than about 95 wt% of the un-depolymerized-polyester; from about 10 wt% to about 90 wt%, greater than about 10 wt%, greater than about 15 wt%, greater than about 20 wt%, less than about 50 wt%, less than about 75 wt%, or less than about 90 wt% of the comonomer; 0 wt%, about 0.1 wt%, about 1 wt%, less than about 5 wt%, less than about 10 wt%, or less than about 20 wt% of the optional alkylene glycol; less than about 2 wt%, less than about 1.5 wt%, less than about 1.0 wt%, greater than about 0.05 wt%, greater than about 0.1 wt%, greater than about 0.5 wt% of the second catalyst; and less than about 2 wt%, less than about 1.5 wt%, less than about 1.0 wt%, greater than about 0.05 wt%, greater than about 0.1 wt%, or greater than about 0.5 wt% of ring opening polymerization catalyst, wherein all the wt% are based on the total weight of the copolymerization feed mixture. In exemplary embodiments, the copolymerization feed mixture includes from about 0.1 wt% to about 95 wt% of the un-depolymerized-polyester; from about 10 wt% to about 90 wt% of the comonomer, 0 wt% to about 20 wt% of the optional alkylene glycol; from about 0.05 wt% to about 2 wt% of the second catalyst; and about 0.05 wt% to about 2 wt% of the ring opening polymerization catalyst. The depolymerized-polyester product, comonomer, optional alkylene glycol, second catalyst and ring opening polymerization catalyst can be present in the copolymerization feed mixture in any specific wt% or range of wt% falling within their above respective ranges. In exemplary embodiments, the ring opening polymerization catalyst includes tin (II) octoate, aluminum alkoxides, zinc oxide, 1,5,7-triazabicyclo [4.4.0] dec-5-ene, 1,8– triazabicyclo [5.4.0]-undec-7-ene, or mixtures thereof. In exemplary embodiments, the second catalyst includes antimony (III) oxide, titanium (IV) butoxide, germanium oxide, zinc acetate, or mixtures thereof. In exemplary embodiments, the step of heating the copolymerization feed mixture in the process for producing the renewable copolymer is carried out at a temperature in the range of from about 125 °C to about 350 °C, from about 150 °C to about 350 °C, from about 200 °C to about 300 °C or any specific temperature or range of temperatures falling within the above ranges. In exemplary embodiments, the step of heating the copolymerization feed mixture in the process for producing the renewable copolymer is carried out for about 15 minutes to about 20 hours, for about 30 minutes to about 15 hours, for about 1 hour to about 12 hours, for about 3 hours to about 7 hours or any specific timepoint or range of timepoints falling within the above ranges. In exemplary embodiments, the step of heating the copolymerization feed mixture in the process for producing the renewable copolymer is carried out stage-wise, wherein during a first stage, the copolymerization feed mixture is heated for about 10 minutes to about 7 hours at a temperature of from about 125 °C to about 270 °C and, wherein during a subsequent second stage, the copolymerization feed mixture is heated for about 15 minutes to about 13 hours at a temperature of from about 200 °C to about 350 °C. The time and temperature that the first stage and second stage of the heating step can be carried out at can include any specific time point or temperature and / or any range of timepoints or temperatures falling within the above ranges. In exemplary embodiments, the step of heating the copolymerization feed mixture in the process for producing the renewable copolymer is carried out under an inert gas. In exemplary embodiments, the step of removing the copolymer-residual volatile organic compound in the process for producing the renewable copolymer is carried out under a vacuum. In exemplary embodiments, the copolymerization feed mixture includes polyethylene terephthalate. In exemplary embodiments, the comonomer used in the contacting step includes butyrolactone, valerolactone, or mixtures thereof. In exemplary embodiments, the renewable copolymer is a hot melt adhesive, wherein the renewable copolymer is a semi-liquid or liquid when heated to copolymer’s melting softening temperature and solidifies at room temperature. In exemplary embodiments, the renewable copolymer is a pressure sensitive adhesive, wherein the renewable copolymer is semi-liquid at room temperature. In exemplary embodiments, the renewable copolymer has one or more of the following properties: (i) a peel adhesion failure temperature of at least 20 °C, as measured according to a modified ASTM 4498 method, (ii) a shear adhesion failure temperature of at least 70 °C, as measured according to ASTM 4498 method, and / or (iii) a viscosity of at least 100 cPs, as measured according to ASTM3236 method. In exemplary embodiments, the renewable copolymer is a transparent or semi- transparent adhesive having a transmittance of at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% according to the standard ASTM D1003 / ISO 13468, and / or a haze (turbidity or cloudiness) of less than 40%, less than 30%, less than 15%, less than 10%, or less than 5%, according to the standard ASTM D1003 / ISO / DIS 14782. In exemplary embodiments, the step of heating the copolymerization feed mixture is carried out under vacuum for in situ removal of the copolymer-residual volatile organic compound during copolymerization. In exemplary embodiments, the renewable copolymer has a peel adhesion failure temperature (PAFT) of at least about 20 °C, at least about 25 °C, at least about 40 °C, or at least about 50 °C. In exemplary embodiments, the renewable copolymer has a shear adhesion failure temperature (SAFT) of at least about 25 °C, at least about 30 °C, at least about 50 °C, at least about 100°C or at least about 150 °C. Another aspect of the present disclosure is a process for creating a blended copolymer, the process including one or more of: blending an un-depolymerized polyester and any renewable copolymer prepared according to any one of the processes disclosed herein to create a blending feed mixture; and heating the blending feed mixture under stirring at a temperature in the range of about 150 °C to about 300 °C for a blending time in the range of about 15 minutes to about 20 hours to create the blended copolymer. In exemplary embodiments, the blending feed mixture contains from about 0.1 wt% to about 95 wt% of the un-depolymerized polyester and from about 10 wt% to about 90 wt% of a comonomer. In exemplary embodiments, the blended copolymer is semi-solid, semi-transparent or transparent. In exemplary embodiments, the blended copolymer is transparent and has a transmittance of at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% according to the standard ASTM D1003 / ISO 13468, and / or a haze (turbidity or cloudiness) of less than 40%, less than 30%, less than 15%, less than 10%, or less than 5%, according to the standard ASTM D1003 / ISO / DIS 14782. Another aspect of the present disclosure is a process for producing renewable polyamides, polyurethanes, epoxy polymers, and / or ring-opening polymers using any one of the depolymerized-polyester products prepared according to the processes disclosed herein as a feedstock. In exemplary embodiments, the process produces renewable polytrimethylene terephthalate (PTT), renewable polybutylene terephthalate (PBT), renewable polyethylene-co- isorbite terephthalate (PEIT), renewable polyamides, renewable polyurethanes, renewable epoxy polymers, and / or renewable ring-opening polymers. Those of ordinary skill in the art understand that the heating time and temperature for many of the processes disclosed herein will depend upon the amounts of components in the feed mixtures and the compositions of the catalysts. Accordingly, those of ordinary skill in the art are readily capable of determining what heating times and temperatures are appropriate for the various embodiments of the processes disclosed herein. To summarize, the present disclosure provides novel and innovative processes to hydrolytically depolymerize post-consumer PET, without using any catalytic materials, to create oligomeric / monomeric products that can be used as PET building blocks and / or as a feedstock to produce renewable polymers. The processes can be used to depolymerize a wide range of post-consumer PET feedstocks, such as, but not limited to, clear PET, color PET, PETG, mixed PET, mixed plastics, pre-process PET flakes, un-processed PET machine cut flakes, ocean-borne PET, river-borne PET, lake-borne PET, or landfill-borne PET. The scalability of the depolymerization processes disclosed herein allows, for example, the processes to be performed in a variety of pressure metal pressure reactors of different sizes (e.g., 250 mL to 5L). The depolymerized-polyester oligomer products disclosed herein can be polymerized to produce renewable PET and can be characterized by thermal, chromatographic and viscometric methods. For example, the renewable PET samples produced from the processes disclosed herein can be characterized to determine their intrinsic viscosity (IV), glass transition temperature (Tg), and / or melting temperature (Tm). The depolymerized-polyester oligomer products disclosed herein can also be polymerized with different amounts of caprolactone to produce adhesive copolymers and characterization of these copolymers can be achieved by thermal, chromatographic, viscometric, and adhesion testing methods. For example, the copolymer samples can be characterized to determine their glass transition temperature (Tg), molecular weight, viscosity, melting softening point, peel adhesion failure temperature (PAFT), and / or shear adhesion failure temperature (SAFT). The un-depolymerized polyester products produced from the methods disclosed herein can be polymerized with different amounts of caprolactone to produce adhesive copolymers and characterization of these copolymers can be achieved with thermal, chromatographic, viscometric, and adhesion testing methods. For example, these copolymers can be characterized to determine their glass transition temperature (Tg), molecular weight, viscosity, melting softening point, peel adhesion failure temperature (PAFT), and / or shear adhesion failure temperature (SAFT). The copolymers made from the polymerization processes disclosed herein can be blended with un-depolymerized polyesters, such as those disclosed herein, to produce adhesive copolymers and characterization of these blended copolymers can be achieved with thermal, chromatographic, viscometric, and adhesion testing methods. For example, these blended copolymers can be characterized to determine their glass transition temperature (Tg), molecular weight, viscosity, melting softening point, peel adhesion failure temperature (PAFT), and / or shear adhesion failure temperature (SAFT). In exemplary embodiments, the processes and compositions disclosed herein can be construed as excluding any element or process step that does not materially affect the basic and novel characteristics of the composition or process. Additionally, in some exemplary embodiments, the compositions and processes disclosed herein can exclude any element or process step not explicitly excluded in an embodiment specified herein. The depolymerized-polyester monomers and oligomers produced from the depolymerization processes disclosed herein are a versatile precursor for further modifications and syntheses of various commercial polymers. These monomers and oligomers can have alcohol and acidic end groups which enable a wide array of polymer synthesis schemes including, but not limited to, renewable polyesters. For example, the depolymerized-polyester oligomer products of the present disclosure can be utilized as an initiator for ring-opening polymerization of various monomers, such as caprolactone, which can be used to make, for example, PET-co-caprolactone copolymers (using depolymerizd-PET oligomeric product) that can be utilized as adhesives or compatibilizers in polymer blends. Additionally, polycondensation reactions can be performed with the products disclosed herein and a wide variety of other materials to create novel polymeric materials. An example of such polycondensation is the reaction between PET and poly(tetramethylene oxide), which can result in the creation of versatile multi-block segmented poly(ether-ester)s, such as poly(ethylene terephthalate-co-1,4-cyclohexanedimethylene terephthalate)-block- poly(tetramethylene oxide), which has highly controlled melt and mechanical properties. Further modification of the PET oligomers produced by the processes disclosed herein can be achieved by initially reacting them with an excess quantity of ethylene glycol under polycondensation conditions to convert the precursor into a di-alcohol endcap product. This di- alcohol endcap product can subsequently be reacted with isothiocyanates to form PET- polyurethanes, in which case the PET behaves as a chain extender in the stepwise reaction. Similarly, reactions of the di-alcohol endcap product with diglycidyl compounds can be used for the preparation of epoxies. Conversely, reactions of the di-alcohol endcap product with excess terephthalic acid can convert the product into a diacid. This diacid can subsequently be reacted with diamines in a polycondensation condition to form polyamides. The potential applications for the versatile precursors and the depolymerized-polyester oligomer products of the present disclosure are diverse and hold great promise for future developments. The depolymerized monomers, terephthalic acid (TA) and ethylene glycol (EG), disclosed herein can be utilized as feedstock for producing renewable PET without requiring TA and EG from petroleum. Additionally, depolymerized TA can be used as a feedstock to produce polytrimethylene terephthalate, polybutylene terephthalate, polyethylene-co-isorbite terephthalate and polyurethane, epoxy and other polymers via suitable polymerization reactions with propanediol, butanediol and other relevant monomers or a mixture of monomers. EXAMPLES The present disclosure will be described in more detail with reference to the following Examples, which show exemplary embodiments in accordance with the present disclosure. The present disclosure is not limited to these exemplary embodiments. ABBREVIATIONS: PET = Polyethylene terephthalate TPA = Terephthalic acid EG = Ethylene glycol HFIP = Hexafluoro-2-propanol DMSO = Dimethyl sulfoxide PETG = Polyethylene terephthalate glycol GPC = Gel-permeation chromatography HPLC = High performance liquid chromatography NMR = Nuclear magnetic resonance ICP-MS = Inductively coupled plasma mass spectrometer DSC = Differential scanning calorimeter MW = Molecular weight ASTM = American society for testing materials MATERIALS: Materials and their source are listed below: All chemicals except caprolactone were purchased from VWR International. Caprolactone was purchased from Fischer Scientific. PET polyester feedstock was obtained from our commercial suppliers. METHODS: TITRIMETRIC ANALYSIS Hydroxyl content of the depolymerized-polyester product was estimated using a reflux phthalation method described in ASTM D 4274-99. Briefly, 1.5 grams of depolymerized- polyester oligomer product was dissolved in 25 mL of the phthalic anhydride pyridine reagent into each flask. The flask was then introduced to the oil batch maintained at 115 °C for 1 hour. The depolymerized powder was allowed to react with phthalic anhydride during this time. The unreacted phthalic anhydride was then titrated against 0.5 M NaOH solution in presence of a phenolphthalein indicator to a pink end point that persists for at least 15 seconds. Hydroxyl number was then estimated as follows Hydroxyl number = [(B-A)×N×56.1] / W where: A = NaOH required for titration of the sample, mL, B = NaOH required for titration of the blank, mL, N = normality of the NaOH, and W = sample used, in grams. Carboxyl content measurement of depolymerized-polyester oligomer products were estimated according to ASTM D4662-08. Briefly, 1.5 grams of depolymerized-polyester oligomer product was weighed into an Erlenmeyer flask containing 25 mL pyridine. The sample was mixed at 110 °C to dissolve the reaction product. The solution was left to reflux for 30 minutes. The samples were then titrated with 0.1 M potassium hydroxide solution in the presence of a phenolphthalein indicator. The acid number was estimated as follows Acid number = [(B-A)×N×56.1] / W where: A = KOH required for titration of the sample, mL, B = KOH required for titration of the blank, mL, N = normality of the KOH, and W = sample used, in grams. Acid number measurement of the depolymerized-polyester monomer products were estimated according to the ASTM D8032–20 method. Briefly, 1.5 grams of depolymerized- polyester monomer product was weighed into an Erlenmeyer flask containing 20 mL DMSO. The sample was mixed to dissolve the product and 20 mL deionized water was added to this solution. The samples were then titrated with 0.5 M sodium hydroxide solution in the presence of a phenolphthalein indicator. The acid number was estimated as follows Acid number = [(A-B)×C×56.11] / W where: A = NaOH solution required for titration of the sample, mL, B = NaOH solution required for titration of the blank, mL, C = molarity of the NaOH solution, and W = sample used, g. DIFFERENTIAL SCANNING CALORIMETRY (DSC) Differential scanning calorimetry (DSC) profiles of the samples were recorded on a DSC Q20 series TA Instrument under a N2 atmosphere. Prior to use, the interior chamber was brushed clean and heated to 100 °C for 5 minutes to remove residual / volatile compounds. Depolymerized-polyester oligomer product samples were taken in an aluminum pan for measurement. The samples were subjected to 2 heating and cooling cycles in temperature ranges of -60 °C to 265 °C at a heating / cooling rate of 10°C min-1. GEL-PERMEATION CHROMATOGRAPHY (GPC) GPC of the depolymerized-polyester oligomer products and polymer samples was performed using an Agilent GPC / SEC software. The system consisted of a model G1311A pump, a model G1313A autosampler, and a model G7162A refractive index detector. Elution was done with 1 mL / min flow of chloroform across two ResiPore 7.5 x 300 mm columns in sequence. These samples were tested against Agilent Technologies EasiCal PS2 polystyrene standards. These standards were prepared according to instructions using chloroform. The manufacturer provided molecular weight data for each standard and this data was inputted into the Agilent GPC / SEC software. HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) HPLC of the depolymerized-polyester TPA products was performed using a ZORBAX Eclipse Plus C184.6 × 100 mm, 3.5µm column. Sample solutions were prepared in DMSO and the elution was done with 1 mL / min flow of acetonitrile / acidified HPLC grade water (90:10 v / v). Acidified HPLC grade water was prepared by adding formic acid in 0.1% v / v concentration. The HPLC system contained a model G1311A pump, a model G1313A autosampler, and a model G1315B diode array detector. The TPA concentration in the depolymerized-polyester monomer products was estimated using a calibration plot of commercial TPA input into the ChemStation software. HPLC of the depolymerized-polyester monomer liquid products was performed using a Hi-Plex Ca, 300 ×7.7 mm column. Sample solutions were prepared in HPLC grade water and the elution was done with 0.6 mL / min flow of HPLC grade water. The HPLC system contained a model G1311A pump, a model G1313A autosampler, and a model G7162A refractive index detector. Concentration of the depolymerized-polyester monomer liquid products was estimated using the calibration plot of commercial anhydrous EG input into the ChemStation software. INTRINSIC VISCOSITY (IV) IV values of samples were measured by an Ubbelohde capillary viscometer using an ASTM D4603-18 method. A 0.5 wt.% polymer solution was prepared in a 60:40 phenol / 1,1,2,2-tetrachloroethane solution. The prepared solution was injected into a glass capillary viscometer and the measurement results were recorded as time (in seconds) it took for the solution to flow between two fixed points marked on viscometer. Relative viscosity was calculated as a ratio of the time it took for the sample solution (t) and the time it took for the 60:40 phenol / 1,1,2,2-tetrachloroethane solvent (t0) to flow between these two points. Relative viscosity was converted to intrinsic viscosity using the Billmeyer relationship as follows. ɳr (Relative viscosity) = t / t0 ɳ (Intrinsic viscosity) = 0.25 (ɳr– 1 + 3 ln ɳr) / C where: t = average sample solution flow time, t0 = average solvent flow time, and C = polymer solution concentration, g / dL. VISCOSITY: Viscosity was measured using a Brookfield viscometer according to a ASTM3236 method. METTLER SOFTENING POINT: Mettler softening point was measured using a Mettler dropping point apparatus according to the ASTM D3954 method. This test is a measure of the softening point of the material. This method is used to measure the temperature at which the materials soften enough such that flow will occur. PEEL ADHESION FAILURE TEMPERATURE (PAFT) PAFT testing was performed using a modified ASTM 4498 method. This modified ASTM 4498 testing is an adhesion test where the material is heated to 177 °C to become fully molten, poured onto a piece of standardized kraft paper, then immediately bonded to another piece of kraft paper. The bond is allowed to stand overnight at room temperature. The samples are then cut into 1” x 1” samples and hung in an oven with 100 gram weights as loads in the peel mode of failure. The oven is heated at a rate of 30 °C / hour and when the weight falls from the sample, the temperature is recorded. This test helps determine the relative sensitivity of a bond made with this material when exposed to higher temperatures. This is a key property for hot melt adhesives since many hot melts are used in a wide variety of environmental conditions. SHEAR ADHESION FAILURE TEMPERATURE (SAFT) SAFT testing was performed using the ASTM 4498 method. This test is set up similarly to the PAFT method, except that the weight is hung such that the failure is in the shear mode and the weight is 500 grams. This test is another indication of how well a given adhesive will hold up when exposed to higher temperatures. EXAMPLE 1: POST-CONSUMER PET DEPOLYMERIZATION TO DEPOLYMERIZED OLIGOMER PRODUCT The depolymerization reaction conditions in terms of reactant ratios, catalyst concentration, type, temperature, and time were varied in this example. The depolymerized- polyester oligomer / monomer products were characterized by thermal, chromatographic, and titrimetric methods. Specifically, the depolymerized-polyester oligomer products were characterized to determine the functional groups (hydroxyl, carboxylic), molecular weight, glass transition temperature (Tg), and melting temperature (Tm). The depolymerized-polyester monomer products were characterized to determine carboxyl acid group content, particle size, color, purity, and metal contents. Hydrolytic depolymerization of post-consumer PET flakes to depolymerized oligomer product was performed in water without adding any catalysts. The reaction was carried out in a metal reactor with a 5L internal volume equipped with a mechanical stirrer, an electrical heating furnace, a pressure gauge and safety features. After the hydrolytic depolymerization reactions occurred for a set amount of time, the reactor was cooled and the depolymerized product was filtered using a 25µ filter. The recovered solid oligomer product was air dried in a vacuum oven overnight to obtain free-flowing particles. The solubility study of dried oligomer product in HFIP solvent indicated formation of 90% oligomer, with the remaining 10% being TPA. The yields of oligomers and TPA were confirmed by GPC and HPLC analyses of the respective fractions upon dissolving in HFIP and DMSO solvents, respectively. FIG. 1 shows a pictorial representation of the dried oligomer product. The average MW of produced oligomers as a function of depolymerization time is shown in FIG. 2. The average MW of oligomers in the oligomer product was reduced from 6200 g / mol at 10 hours of depolymerization to 2140 g / mol at 21 hours of depolymerization. Table 1 summarizes the MW distribution (MWD) of different oligomer fractions in the oligomer product characterized by GPC. Table 1: Molecular Weight Distribution of Depolymerized Oligomer Products. Reaction conditions: PET to water weight ratio = 6.5; reaction temperature = 160 °C; reaction time varied from 10 hours to 21 hours and reactor’s mechanical stirrer speed 1300 RPM. The results of Table 1 and FIG. 2 show that the MWD of oligomers in the depolymerized oligomer products largely depended on the reaction time. The GPC chromographs also demonstrated that the carboxyl content of the oligomer products was 26.9 ± 2 mg KOH / g, as per the ASTM D4662-08 method, and the hydroxyl content was 32 ± 2 mg KOH / g, as per the ASTM D 4274-99 method. EXAMPLE 2: POST-CONSUMER PET DEPOLYMERIZATION TO DEPOLYMERIZED MONOMER PRODUCT These experiments (Experiment No. 1-20) were carried in a metal reactor having an internal volume of 250 mL. The reactor was equipped with a mechanical stirrer, an electrical heating furnace, a pressure gauge and safety features. Municipal water was used as a solvent. The reaction time and water to PET weight ratios varied from 2 hours to 12 hours and from 3 to 10, respectively, at a fixed temperature of 200 °C and stirring speed of 900 RPM. Experiment No. 21 was carried out in a 5L autoclave at a temperature of 200 °C and a stirring speed of 1300 RPM for 14 hours using a water to PET ratio of 10. The reaction conditions are shown in Table 2. The depolymerized products were filtered using a 25µ filter to separate liquid and solid phases. The solid product was washed with water to remove any residual EG and dried in a vacuum oven overnight at 65 °C to obtain free-flowing powder. Table 2: Experimental Conditions for PET Depolymerization to Depolymerized Monomer Products. HPLC and NMR analyses of the depolymerized monomeric solid products confirmed the product as TPA (FIG.3 and FIG. 4). HPLC analysis of the samples from all experiments was performed by dissolving each sample in DMSO and injecting the solutions into a HPLC equipped with a ZORBAX Eclipse Plus C18 column. Acid numbers for the depolymerized TPA products from these experiments were measured to evaluate the percentage of TPA formation as a function of reaction time. The acid number was measured by a colorimetric titration method (ASTM D8032–20) and was compared with commercial TPA’s acid number. For comparison, the acid number of commercial TPA was estimated, by the same method, as 670.5 mg KOH / g. The acid number of the depolymerized TPA products were lower at shorter reaction times (FIG.5). These acid numbers increased with the depolymerization reaction time and plateaued at about 6 hours (FIG.5). Experiment No.21 showed complete depolymerization of PET to TPA and EG after 14 hours of depolymerization in a 5 L autoclave. The stoichiometric quantity of EG (EG / PET ratio of ~0.3) in the depolymerized monomeric liquid products was estimated using HPLC. Other key specifications (e.g., appearance, color, particle size, purity, metal content) of the depolymerized TPA products were determined by visual observation, spectrophotometric, screening, HPLC and ICP-MS methods. The appearance, color index, particle size distribution and purity values were similar to those of the commercial TPA sample (Table 3). The majority of metal content (Mg, Co, Cr, Mn, Ni, Mo, Ti) was less than 2 ppm. Table 3: Specifications of Depolymerized TPA Products. The liquid phase of all the experiments listed in Table 2 was analyzed by HPLC using a Hi-Plex Ca 300mm x 7.7mm column. The retention time of EG in the liquid phase (FIG.6) matched with the retention time of standard commercial EG (FIG. 7). A nearly quantitative yield of EG (about 0.3 g EG per gram of PET) was achieved after 6 hours of depolymerization. The yields of EG, measured by the HPLC method, per gram of PET increased as a function of reaction time (FIG. 8). Water from the liquid phase containing depolymerized EG was separated by distillation at about 120-140oC. Collected depolymerized EG was further distilled at about 220oC to collect clear EG product. The appearance of the distilled EG sample was similar to that of commercial EG (FIG. 9). HPLC analysis of the distilled depolymerized EG product showed its purity was about 98% with the remainder being a small amount of diethylene glycol (~1-2%) (FIG.10). EXAMPLE 3: POLYMERIZATION OF DEPOLYMERIZED OLIGOMER PRODUCT TO RENEWABLE PET The polymerization of the depolymerized oligomer product was performed in a 250 mL metal reactor equipped with a condenser, a vacuum pump and an inlet for nitrogen gas. The following experimental methodology was followed. First, the depolymerized oligomer product was melted at 240°C under N2gas. Separately, a solution was prepared by mixing an appropriate amount of Sb2O3 catalyst with a pre-determined amount of EG. The mixture was added to the reactor under vacuum, and the temperature of the reactor was raised to 240°C under stirring and continued stirring for 30 minutes under N2. The mixture was then stirred for 3 hours at 240°C for the esterification reaction. After 3 hours, EG removal was carried out by first opening the reactor outlet to partially pull EG vapors and reduce reactor pressure before opening the N2inlet. The esterified product was white. The obtained oligomer was then subjected to polycondensation at 280°C and a 500 RPM stirring speed under vacuum for 2.5 hours to 6.5 hours to obtain a renewable PET. Table 4 shows the reaction conditions at 280°C. Table 4: Reaction Conditions of Polycondensation Experiments and MW of the Synthesized Renewable PET. DP=depolymerized product. Sb2O3= antimony oxide, TBP = tributyl phosphate. A RPM decrease during the polycondensation reactions was an indication of an increased MW of the synthesized PET. The color of the resulted PET was similar to that obtained from standard polymerization of standard bis-hydroxyl terephthalate (BHET) (FIG. 11). The MW of the synthesized renewable PET was similar to that obtained from BHET synthesized PET (Table 4). The MW of renewable PET, obtained from polymerization of depolymerized oligomer product after 21 hours of depolymerization of PET, was 54092 g / mol (Experiment No.3). This is comparable to PET obtained from standard BHET using similar polymerization conditions, which resulted in a MW of 56140 g / mol (Experiment No. 1). The depolymerized oligomer product produced from the 18-hour experiment needed a longer polycondensation time to produce a renewable PET of high MW and IV values. Experiments No.4-7 showed that MW and IV of the synthesized renewable PETs increased with increasing polycondensation times. A GPC profile of the renewable PET produced from Experiment No.7 is shown in FIG.12. DSC characterization (FIG. 13) of the renewable PET of Experiment No. 6 showed glass transition temperature (Tg) and melting temperature (Tm) values of 69°C and 249°C, respectively. These values for commercial PET flakes are 80°C and 250°C, respectively. EXAMPLE 4: POLYMERIZATION OF DEPOLYMERIZED OLIGOMER TO ADHESIVE COPOLYMER 96 grams of depolymerized oligomer was mixed with a mixture containing 64 grams of caprolactone, 60 mg of Sb2O3, 960 mg of tin (II) octoate and 30 mg of tributyl phosphate in a 250 mL metal reactor. The mixture was stirred at 900 RPM for 1 hour at room temperature to form a homogenous mixture. The mixture was then purged with nitrogen for 15 minutes before ramping the temperature to 240°C. Then nitrogen outlet was closed and the reaction mixture was maintained under a nitrogen atmosphere at 240°C for 3 hours. After 3 hours vacuum pulling was started to remove the unreacted caprolactone for 30 minutes. A white colored, viscous and gluey adhesive copolymer was formed with a MW of 12169 g / mol and a Tg value of -6 °C (FIG.14). FIG.15 shows the GPC plot of this copolymer. Viscosity, melting softening temperature, PAFT and SAFT of this copolymer were measured as 1200 cPs (at 300 ^F), 94 °C, 24 °C and 74 °C, respectively. EXAMPLE 5: SYNTHESIS OF ADHESIVE COPOLYMER FROM PET FLAKE 60 grams of clear PET flakes and 30 mg of a tributyl phosphate mixture was melted at 255°C for 30 minutes. A mixture containing 40 grams of caprolactone, 40 mg of Sb2O3and 600 mg of tin (II) octoate was then added to the molten PET mixture. The reaction mixture was placed under nitrogen at 255°C and a 600 RPM stirring speed for 10 minutes. After 10 minutes, the heater was turned off and vacuum pulling was applied for 10 minutes to remove the unreacted caprolactone and any volatile vapors formed during the reaction. A light-brown colored, viscous and gluey adhesive copolymer was formed. The MW of this copolymer was measured as 39036 g / mol. It’s Tgvalue was -2°C . Viscosity, melting softening temperature, PAFT and SAFT of this copolymer were measured as 29,000 cPs (at 300 ^F), 134 °C, 48 °C and 122 °C, respectively. EXAMPLE 6: BLENDING OF COPOLYMER FROM EXAMPLE 4 WITH PET POLYESTER 50 grams of PET flakes were melted at 255 °C and cooled down to 200 °C.50 grams of copolymer from EXAMPLE 4 were then added to the reactor and blended for 15 minutes at 255 °C and at a stirring speed of 600 RPM. A white, flexible, tacky blend was formed with a MW of 11046 g / mol. DSC analysis of the blended polymer sample (FIG.16) showed a single Tg value of 15 °C, which was between the Tgvalue of 79 °C for PET and -6 °C for the copolymer. These results indicate that the copolymer is compatible with the PET resin and their blends can be prepared to improve the viscoelastic properties of the copolymer. Viscosity, melting softening temperature, PAFT and SAFT of this copolymer were measured as 3700 cPs (at 350 °F), 169 °C, 44 °C and >150 °C, respectively. It will be appreciated by those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the disclosure is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.

Claims

CLAIMS 1. A process for depolymerizing a polyester comprising the steps of: a) contacting the polyester with water to form a reaction mixture; and b) heating the reaction mixture to at least 100 °C for an amount of time sufficient to depolymerize at least a portion of the polyester to a depolymerized-polyester product, wherein the depolymerized-polyester product comprises one or more of a depolymerized-polyester monomer product and a depolymerized-polyester oligomer product.

2. The process according to Claim 1, wherein the polyester comprises at least one of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polybutylene adipate terephthalate, polyethylene furanoate, polytrimethylene furanoate, polybutylene furanoate, polycarbonate, polyglycolic acid, polylactic acid, poly-2-hydroxy butyrate, polyhydroxyalkanoate, poly(3-hydroxybutyrate-co-3- hydroxyvalerate), polycaprolactone, and polybutylene succinate.

3. The process according to Claims 1 or 2, wherein the polyester comprises clear polyethylene terephthalate, colored polyethylene terephthalate, mixed polyethylene terephthalate, or mixtures thereof.

4. The process according to any one of Claims 1-3, wherein the polyester is clear ocean-borne polyethylene terephthalate, colored ocean-borne polyethylene terephthalate, mixed ocean- borne polyethylene terephthalate, clear river-borne polyethylene terephthalate, colored river-borne polyethylene terephthalate, mixed river-borne polyethylene terephthalate, clear lake-borne polyethylene terephthalate, colored lake-borne polyethylene terephthalate, mixed lake-borne polyethylene terephthalate, clear landfill-borne polyethylene terephthalate, colored landfill-borne polyethylene terephthalate, mixed landfill-borne polyethylene terephthalate or mixtures thereof.

5. The process according to any one of Claims 1-4, wherein the polyester is a PET bottle, a PET film, a PET fiber, a PET fabric, a PET flexible packaging, a PET substrate, a PET article containing a metal layer, or mixtures thereof.

6. The process according to any one of Claims 1-5, wherein the polyester is in particulate form or flake form having an average particle size in a range of from about 5 µm to about 100 mm.

7. The process according to any one of Claims 1-6, wherein the step of heating the reaction mixture is carried out at a temperature range of from about 120 °C to about 300 °C.

8. The process according to any one of Claims 1-7, wherein the step of heating the reaction mixture is carried out for about 1 hour to about 35 hours.

9. The process according to any one of Claims 1-8, wherein the depolymerized-polyester oligomer product comprises one or more oligomers having a molecular weight greater than 166 Da.

10. The process according to any one of Claims 1-9, wherein the depolymerized-polyester product comprises one or more oligomers having a molecular weight in a range of 166 to 10000 Da.

11. The process according to any one of Claims 1-9, wherein the depolymerized-polyester monomer product comprises one or more monomers having a molecular weight in the range of 62 to 166 Da.

12. A composition comprising one or more of a depolymerized-polyester monomer product and a depolymerized-polyester oligomer product, obtained from the process according to any one of claims 1-11.

13. A process for producing a renewable polyester comprising the steps of: a) contacting the depolymerized-polyester product prepared according to any one of claims 1-11 with a catalyst and an alkylene glycol to form a polymerization feed mixture, wherein the depolymerized-polyester product comprises one or more of a depolymerized-polyester monomer product and a depolymerized-polyester oligomer product or a mixture of depolymerized-polyester monomers and depolymerized-polyester oligomers; b) polymerizing the polymerization feed mixture by esterification and a subsequent polycondensation at a temperature of at least 100 °C, optionally in the presence of an inert gas, to produce a post-polymerization product mixture containing the renewable polyester; and c) removing a residual volatile organic compound, optionally in the presence of the inert gas, from the post-polymerization product mixture; wherein the residual volatile organic compound comprises one or more of depolymerized-polyester monomers and the alkylene glycol, and wherein the polymerization feed mixture comprises from about 30 wt% to about 95 wt% of depolymerized-polyester product, from about 5 wt% to about 70 wt% of thealkylene glycol, and less than 0.4 wt% of the catalyst, based on the total weight of the polymerization feed mixture.

14. The process according to Claim 13, wherein the catalyst comprises antimony (III) oxide, titanium (IV) butoxide, germanium oxide, zinc acetate, or mixtures thereof.

15. The process according to Claim 13 or 14, wherein the step of polymerizing is carried out under an inert gas.

16. The process according to any one of Claims 13-15, wherein the step of polymerizing is carried out at a temperature in a range of from about 100 °C to about 350 °C, or from about 200 °C to about 280 °C.

17. The process according to any one of Claims 13-16, wherein the step of polymerizing is carried out for about 1 hour to about 20 hours.

18. The process according to any one of Claims 13-17, wherein the step of polymerizing comprises heating the polymerization feed mixture stage-wise; wherein during a first stage the polymerization feed mixture is heated for about 1 hour to about 4 hours at a temperature in the range of about 100 °C to about 320 °C, and wherein during a second stage the polymerization feed mixture is heated for about 1 hour to about 10 hours at a temperature in the range of from about 200 °C to about 350 °C.

19. The process according to any one of Claims 13-18, wherein the step of removing the residual volatile organic compound is carried out under vacuum.

20. The process according to any one of Claims 13-19, wherein the step of polymerizing is carried out under vacuum for in situ removal of the residual volatile organic compound.

21. The process according to any one of Claims 13-20, wherein the renewable polyester is a renewable polyethylene terephthalate and the alkylene glycol is ethylene glycol.

22. The process according to any one of Claims 13-21, wherein the renewable polyester has a glass transition temperature in the range of about 40°C to about 85°C and an intrinsic viscosity in the range of about 0.4 dL / g to about 0.8 dL / g.

23. A process for producing a renewable copolymer comprising the steps of: a) contacting the depolymerized-polyester product prepared according to any one of claims 1-11 or un-depolymerized polyester with a comonomer, and optionally with alkylene glycol, to form a copolymerization feed mixture, wherein the comonomer comprises caprolactone, a caprolactone-based oligomer, a caprolactone-based polymer, or a mixture thereof;b) heating the copolymerization feed mixture to at least about 150°C in the presence of a ring opening polymerization catalyst and a second catalyst to form a post- copolymerization product mixture containing the renewable copolymer; and c) removing one or more copolymer-residual volatile organic compounds, optionally in the presence of an inert gas, from the post-copolymerization product mixture, wherein the one or more copolymer-residual volatile organic compounds comprise caprolactone, a caprolactone-based oligomer, the optional alkylene glycol, or mixtures thereof, wherein the copolymerization feed mixture comprises from about 0.1 wt% to about 95 wt% of the depolymerized-polyester product or un-depolymerized polyester, from about 10 wt% to about 90 wt% of the comonomer, from 0 wt% to about 20 wt% of the optional alkylene glycol, less than about 2 wt% of the second catalyst, and less than about 2 wt% of the ring opening polymerization catalyst, based on the total weight of the copolymerization feed mixture.

24. The process according to Claim 23, wherein the ring opening polymerization catalyst comprises tin (II) octoate, aluminum alkoxides, zinc oxide, 1,5,7-triazabicyclo [4.4.0] dec- 5-ene, 1,8–triazabicyclo [5.4.0]-undec-7-ene, or mixtures thereof, and wherein the second catalyst comprises antimony (III) oxide, titanium (IV) butoxide, germanium oxide, zinc acetate or mixtures thereof.

25. The process according to Claim 23, wherein the step of heating the copolymerization feed mixture is carried out at a temperature in the range of about 150 °C to about 350 °C.

26. The process according to any one of Claims 23-25, wherein the step of heating the copolymerization feed mixture is carried out from about 15 minutes to about 20 hours.

27. The process according to any one of Claims 23-26, wherein the step of heating the copolymerization feed mixture is carried out under the inert gas.

28. The process according to any one of Claims 23-27, wherein the step of removing the copolymer-residual volatile organic compound is carried out under vacuum.

29. The process according to any one of Claims 23-28, wherein the comonomer comprises butyrolactone, valerolactone, or mixtures thereof.

30. The process according to any one of Claims 23-29, wherein the renewable copolymer is a hot melt adhesive, wherein the copolymer is a semi-liquid or a liquid when heated to copolymers melting softening temperature and solidifies at room temperature.

31. The process according to any one of Claims 23-29, wherein the renewable copolymer is a pressure sensitive adhesive, wherein the renewable copolymer is semi-liquid at room temperature.

32. The process according to any one of Claims 23-29, wherein the renewable copolymer has at least one of the following properties: (i) a peel adhesion failure temperature of at least 20 °C, as measured according to a modified ASTM 4498 method, and (ii) a shear adhesion failure temperature of at least 50 °C, as measured according to ASTM 4498 method. (iii) A viscosity of at least 100 cPs, as measured according to ASTM3236 method.

33. The process according to any one of Claims 23-29, wherein the renewable copolymer is a transparent or semi-transparent adhesive.

34. A process for creating a blended copolymer, the process comprising: blending an un-depolymerized polyester and a renewable copolymer prepared according to any one of claims 23-29 to create a blending feed mixture; and heating the blending feed mixture under stirring at a temperature in the range of about 150 °C to about 300 °C for a blending time in the range of about 15 minutes to about 20 hours to create the blended copolymer, wherein the blending feed mixture comprises from about 0.1 wt% to about 95 wt% of the un-depolymerized polyester and from about 10 wt% to about 90 wt% of the comonomer, wherein the blended copolymer is a semi-solid, semi-transparent or transparent.

35. A composition comprising: at least one of the renewable polyesters obtained from the process according to any one of Claims 13-22, and the renewable copolymer obtained from the process according to any one of Claims 23-33, and a blended copolymer from the process according to Claim 34.

36. A process for producing renewable polyamides, polyurethanes, epoxy polymers, or ring- opening polymers, the process comprising using a depolymerized-polyester product prepared according to any one of Claims 1-11 as a feedstock.

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