Indicator for showing the degree of depolymerization

Abstract

The present invention provides the use of an indicator for indicating the degree of depolymerization, preferably biodegradability, of a degradable polymer in a polymer composition or an article made from the polymer composition. The present invention further provides a polymer composition comprising an indicator for indicating the degree of depolymerization, and a method for visualizing the degree of depolymerization.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer compositions and articles made from such polymer compositions. More particularly, the present invention relates to degradable polymer compositions and biodegradable polymer compositions, and provides a method for indicating the state of depolymerization of such polymer compositions.

Background Art

[0002] Biodegradable polymers are the answer to many of the current environmental problems caused by pollution and waste management. In recent years, many successful biodegradable alternatives have been developed as substitutes for non-degradable polymers and articles. However, the success of these biodegradable alternatives depends largely on the state of degradation, i.e., the degree of depolymerization of the biodegradable polymer. For consumers, it can be very difficult or even impossible to determine the state of degradation or depolymerization without specialized equipment. For example, an article made from a biodegradable polymer may appear to be in a normal state, but biodegradation may already have started, for example, due to improper storage in a wet state or simply over time. Even if visually intact, the polymer chains inside the article have started to decompose, which may weaken the integrity of the article or limit the time the consumer can store the article itself.

[0003] Therefore, there is a need for methods to indicate the state of degradation or degree of depolymerization to users or consumers. Preferably, these methods do not require any measuring instruments to determine the state of degradation or degree of depolymerization. Preferably, the article already contains all the compounds necessary to determine the state of degradation or degree of depolymerization, so that the user or consumer does not need to add any chemicals when determining the state of degradation or degree of depolymerization. Preferably, these methods for determining the state of degradation or degree of depolymerization do not make the article harmful or toxic. Preferably, any compounds added to the article are all of biological origin and preferably biodegradable.

Summary of the Invention

[0004] Surprisingly, it has been newly discovered that some or all of the above requirements and objectives can be achieved individually or in any combination by using an indicator in a polymer composition further containing a biodegradable polymer. Preferably, the polymer composition comprises a base, a buffer, or a mixture thereof, and / or Preferably, the indicator is chemically incorporated into the polymer composition, preferably copolymerized, and more preferably chemically incorporated into a biodegradable polymer.

[0005] In particular, in one embodiment, the present invention relates to the use of an indicator for indicating the degree of depolymerization, preferably biodegradability, of a degradable polymer in a polymer composition or an article made from the polymer composition, wherein the change in the appearance of the indicator is caused by the depolymerization of the degradable polymer.

[0006] More specifically, the present invention provides the use of an indicator for indicating the degree of depolymerization, preferably biodegradability, of a degradable polymer in a polymer composition or an article made from the polymer composition, wherein the change in appearance of the indicator is caused by the depolymerization of the degradable polymer. The indicator is chemically incorporated into the polymer composition, preferably copolymerized, and more preferably chemically incorporated into a biodegradable polymer.

[0007] In one embodiment, the present invention relates to a polymer composition or an article containing the polymer composition, wherein the polymer composition is An indicator that shows the degree of depolymerization, preferably the degree of biodegradation, in an amount of at least 0.01% by weight to a maximum of 10.00% by weight, At least 0.05% by weight to a maximum of 25.00% by weight of a base, buffer, or mixture thereof, At least 65.00% by weight to a maximum of 99.94% by weight of biodegradable polymers, Includes.

[0008] In some embodiments, the polymer composition contains at least 0.05% by weight to a maximum of 25.00% by weight of a base.

[0009] In some embodiments, the base is selected from a list including NaOH, KOH, Ca(OH)2, CsOH, RbOH, Mg(OH)2, LiOH, Sr(OH)2, Br(OH)2, Na2CO3, NaHCO3, NH4OH, urea, histamine, or mixtures thereof, preferably from a list including NaOH, Na2CO3, NaHCO3, NH4OH, urea, histamine, or mixtures thereof.

[0010] In some embodiments, the base is an inorganic base.

[0011] In some embodiments, the indicator is a chromatic indicator.

[0012] In some embodiments, the indicator is a pH indicator, a complex titration indicator, a redox indicator, a temperature indicator, or a hydrolysis indicator.

[0013] In some embodiments, the indicator is chemically or physically incorporated into the polymer composition.

[0014] In some embodiments, the indicator is chemically incorporated into the polymer composition, more preferably into a biodegradable polymer, and preferably copolymerized.

[0015] In some embodiments, the indicator is a halochromic indicator or an ionochromic indicator, preferably a halochromic indicator.

[0016] In some embodiments, the degradable polymer is a biodegradable polymer, preferably a polymer that can be composted at home.

[0017] In some embodiments, the polymer is a polycondensation polymer, preferably polyester, polyamide, polyimide, polyacetal, polyurethane, polycarbonate, or a mixture thereof, and preferably the polymer is polyester.

[0018] In some embodiments, the indicator is responsive to changes in the concentration of hydrogen ions in the polymer composition or an article made from the polymer composition.

[0019] In some embodiments, the indicator is a natural or synthetic indicator, preferably selected from a list including cresol red, methyl red, bromocresol purple, bromocresol green, chlorophenol, resazurin, bromothymol blue, xylenol, curcumin, alizarin, shikonin, betalain, flavonoids, and anthocyanins, or combinations thereof, or derivatives thereof, preferably copolymerizable derivatives thereof.

[0020] In some embodiments, the color transition range of the indicator is less than pH 7.00, preferably less than pH 6.50, preferably less than pH 6.00, and preferably less than pH 5.50.

[0021] In some embodiments, the pKa of the base and / or buffer is higher than the color transition range of the indicator.

[0022] In some embodiments, the indicator is responsive to changes in ion concentration, temperature, oxidation-reduction potential, and / or hydrolysis conditions.

[0023] In some embodiments, a polymer composition or an article containing the polymer composition, wherein the polymer composition is An indicator that shows the degree of depolymerization, preferably the degree of biodegradation, in an amount of at least 0.01% by weight to a maximum of 10.00% by weight, At least 0.05% by weight to a maximum of 25.00% by weight of a base, buffer, or mixture thereof, At least 65.00% by weight to at most 99.94% by weight of a degradable polymer, and comprises.

[0024] In some embodiments, a polymer composition or an article comprising the polymer composition, the polymer composition at least 0.01% by weight to at most 10.00% by weight of an indicator indicating the degree of depolymerization, preferably the degree of biodegradation, and at least 0.05% by weight to at most 25.00% by weight of a buffer, and at least 65.00% by weight to at most 99.94% by weight of a degradable polymer, and comprises.

[0025] The present invention further provides a method for visualizing depolymerization in a polymer composition or an article comprising the polymer composition, the method comprising the step of incorporating an indicator into the polymer composition, and optionally, the step of forming an article from the polymer composition, and comprises.

[0026] More specifically, the present invention provides a method for visualizing depolymerization in a polymer composition or an article comprising the polymer composition, the method comprising the step of incorporating an indicator into the polymer composition, preferably in an amount of at least 0.01% by weight to at most 10.00% by weight based on the total weight of the polymer composition, and the step of incorporating a base, a buffer, or a mixture thereof into the polymer composition, preferably in an amount of at least 0.05% by weight to at most 25.00% by weight based on the total weight of the polymer composition, and optionally, the step of forming an article from the polymer composition, and comprises.

[0027] In some embodiments, the base, buffer, or mixture thereof is incorporated into the polymer composition by chemical blending or physical blending, preferably by extrusion.

[0028] The present invention further provides a self-indicating biodegradable polymer in which an indicator is chemically incorporated into or in a biodegradable polymer, preferably a biodegradable polymer.

[0029] In some embodiments of the self-directing biodegradable polymer, the indicator is a hydrolysis indicator, and the biodegradable polymer is a polycondensate, preferably a polyester or polyamide, more preferably a polyester.

[0030] The independent and dependent claims describe specific and preferred features of the present invention. Features of the dependent claims may be combined as appropriate with features of the independent claims or other dependent claims.

[0031] The present invention will be described further here. Different aspects of the present invention are defined in more detail in the following text. Each of the aspects defined in this manner may be combined with any other one or more aspects unless explicitly stated otherwise. In particular, any feature or description indicated as preferred or advantageous may be combined with any other feature or description indicated as preferred or advantageous. [Brief explanation of the drawing]

[0032] [Figure 1] This diagram illustrates several possible reaction schemes for incorporating indicators into biodegradable polymers. [Figure 2] This figure shows the results of enzymatic digestion of an article according to an embodiment of the present invention. [Modes for carrying out the invention]

[0033] When describing the present invention, unless otherwise specified in the context, terms used shall be interpreted according to the following definitions.

[0034] Unless otherwise defined, all terms used in the disclosure of the invention, including technical and scientific terms, have the meanings generally understood by a person of ordinary skill in the art to which this invention pertains. Further guidance may be provided to better understand the teachings of this invention by including definitions of terms.

[0035] Different aspects of the present invention are defined in more detail in the following text. Each of the aspects defined in this manner can be combined with any other one or more aspects unless explicitly stated otherwise. In particular, any feature indicated as preferred or advantageous can be combined with any other feature indicated as preferred or advantageous.

[0036] Throughout this specification, any reference to “one embodiment” or “one embodiment” means that a particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment of the present invention. Therefore, the appearance of the phrase “in one embodiment” or “in one embodiment” in various places throughout this specification does not necessarily all refer to the same embodiment, although such instances may occur. Furthermore, certain features, structures, or characteristics may be combined in any preferred manner in one or more embodiments, as will be apparent to those skilled in the art from this disclosure. Moreover, some embodiments described herein include some features included in other embodiments, but do not include others, and combinations of features from different embodiments mean that they fall within the scope of the present invention and form different embodiments that can be understood by those skilled in the art. For example, any one embodiment may be used in any combination in the appended claims and description.

[0037] As used herein, the terms “comprising,” “comprises,” and “comprised of” are synonymous with “including,” “includes,” or “containing,” and are inclusive or non-restrictive, and do not exclude additional, undescribed members, elements, or process steps. It should be understood that as used herein, the terms “comprising,” “comprises,” and “comprised of” include the terms “consisting of,” “consists,” and “consists of.”

[0038] As used herein and in the appended claims, the singular forms "a," "an," and "the" refer to multiple subjects unless the context clearly indicates otherwise. For example, "a step" means one or more steps.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art.

[0040] Enumerations of numerical ranges by endpoints include all integers and, where appropriate, fractions contained within that range (for example, 1-5 may include 1, 2, 3, and 4 if referring to the number of elements, and 1.5, 2, 2.75, and 3.80 if referring to a measured value). Enumerations of endpoints also include the endpoint values ​​themselves (for example, 1.0-5.0 includes both 1.0 and 5.0). Any numerical range enumerated herein is intended to include all subranges contained therein.

[0041] In this specification, the term “about” used when referring to measurable values ​​such as parameters, quantities, and durations means that a variation of ±10%, preferably ±5%, and more preferably ±1% of the specified value is included, insofar as such variation is consistent with the practice of the disclosed invention. The value referred to by the modifier “about” should be understood to also refer to the value itself, which is specifically and preferably disclosed.

[0042] The terms "weight %", "volume %", and "mol %" refer to the weight percentage, volume percentage, or molar percentage of an ingredient, based on the total weight, total volume, or total moles of the ingredient, respectively.

[0043] When describing the present invention, unless otherwise specified in the context, terms used shall be interpreted according to the following definitions.

[0044] This invention is based on the remarkable discovery that the degree of depolymerization of a biodegradable polymer in a polymer composition or an article made from the polymer composition can be indicated using an indicator. This degree of polymerization indication can be used, for example, to indicate the state of biodegradation of the polymer composition or an article made from the polymer composition. The degree of depolymerization information can then be used by the end user to determine the quality of the article made from the polymer composition or to determine whether biodegradation has already begun.

[0045] As used herein, the term “depolymerization” is preferably understood as a shortening of the polymer chain length, which may result from the loss of monomer units or the cleavage of the polymer backbone by chemical or enzymatic reactions.

[0046] In one embodiment, the present invention provides the use of an indicator for indicating the degree of depolymerization, preferably biodegradability, of a degradable polymer in a polymer composition or an article made from the polymer composition, preferably an indicator whose appearance can be altered under the influence of external factors, preferably the change in the appearance of the indicator being caused by the depolymerization of the degradable polymer.

[0047] More specifically, the present invention provides the use of an indicator for indicating the degree of depolymerization, preferably biodegradability, of a biodegradable polymer in a polymer composition or an article made from the polymer composition, wherein the change in appearance of the indicator is caused by the depolymerization of the biodegradable polymer, and the indicator is chemically incorporated into the polymer composition, preferably copolymerized, and more preferably chemically incorporated into the biodegradable polymer.

[0048] In one embodiment, the present invention relates to a polymer composition or an article containing the polymer composition, wherein the polymer composition is An indicator that shows the degree of depolymerization, preferably the degree of biodegradation, in an amount of at least 0.01% by weight to a maximum of 10.00% by weight, At least 0.05% by weight to a maximum of 25.00% by weight of a base, buffer, or mixture thereof, At least 65.00% by weight to a maximum of 99.94% by weight of biodegradable polymers, Includes.

[0049] As used herein, the term "indicator" means Preferably, the presence or absence of a threshold concentration or equivalence point of an external factor, such as a hydrogen ion, or Preferably, the indicator is chemically converted under the influence of external factors that may be hydrolysis conditions such as lipase or hydrolase (preferably, the chemical conversion is hydrolysis of the compound or condensation bonds present in the main chain of the compound, preferably ester groups), This often refers to chemical compounds that change their appearance reversibly.

[0050] Preferably, the change in appearance is a change in color, and more preferably, a change in the wavelength of the reflected light beam. Preferably, the change in appearance appears over a narrow concentration range of external factors near the threshold concentration or equivalence point.

[0051] In some embodiments, the degradable polymer is a biodegradable polymer, preferably an industrial biodegradable polymer, a marine biodegradable polymer and / or a polymer that can be composted at home, preferably an industrial biodegradable polymer and / or a polymer that can be composted at home, preferably a polymer that can be composted at home.

[0052] As used herein, the term “industrial biodegradable polymer” is understood, for example, to be a polymer that conforms to the European standard EN 134323:2000.

[0053] As used herein, the term “home compostable polymer” is preferably understood to mean a polymer conforming to the French standard NF T 51-800:2015.

[0054] As used herein, the term “marine compostable polymer” is preferably understood to mean a polymer conforming to ISO 22403:2020.

[0055] In some embodiments, the biodegradable polymer is selected from a list including polylactic acid (PLA), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polypropylene carbonate (PPC), or mixtures thereof.

[0056] The terms “PLA,” “polylactide polymer,” and “polylactic acid” are synonymous and can be represented by structure (I). As used herein, “PLA” refers to a polymer of lactide (monomer). Lactide can exist in three different geometric structures having diastereomer relationships. Therefore, as used herein, the term “lactide” (or “lactide monomer”) may be L-lactide (derived from two L-lactic acid molecules), D-lactide (derived from two D-lactic acid molecules), meso-lactide (derived from an L-lactic acid molecule and a D-lactic acid molecule), or a mixture of two or more of the above. A 50 / 50 mixture of L-lactide and D-lactide with a melting point of about 126°C is often called D,L-lactide or racemicalactide in the literature (also referred to herein as “rac-Lactide,” “racemicalactide,” or “rac-lactide”). Therefore, the PLA polymers as defined herein may be polymers of lactides (monomers) selected from the group including L-lactide, D-lactide, meso-lactide, racemicalactide, and any mixtures of two or more thereof. [ka]

[0057] Polybutylene succinate (PBS) as defined herein refers to a polymer that can be classified as a polyester, more preferably an aliphatic polyester, and most preferably a biodegradable aliphatic polyester. Polybutylene succinate is composed of repeating units of butylene succinate and can be represented by structure (II). [ka]

[0058] In the art, various methods for producing polybutylene succinates are known. In some embodiments, the process for producing PBS involves esterifying succinic acid with 1,4-butanediol, removing water to form an oligomer, and then performing transesterification under vacuum in the presence of a catalyst such as a derivative of titanium, zirconium, tin, or germanium to provide a high molecular weight polymer. Those skilled in the art will know by analogy how to prepare PES, PPS, PBA, and PBSA.

[0059] Polybutylene succinate terephthalate (PBST), also known as poly(butylene succinate-co-butylene terephthalate), refers to a polyester containing butylene succinate units and butylene terephthalate units, as defined herein.

[0060] As defined herein, polybutylene adipate terephthalate (PBAT) refers to a biodegradable random copolymer, specifically a copolyester of adipic acid, 1,4-butanediol, and dimethyl terephthalate represented by structure (III). [ka]

[0061] Polycaprolactone (PCL) as defined herein refers to polymers that can be obtained by polymerization of caprolactone, more preferably ε-caprolactone. Preferably, polymerization can be carried out by ring-opening polymerization, more preferably by anionic ring-opening polymerization. Polymerization can be carried out in the presence of an initiator and / or a catalyst. Both suitable initiators and catalysts are known in the art. Examples of suitable initiators are metal amides, alkoxides, phosphines, amines, alcohols, water, or organometallic compounds, such as nucleophiles including alkyllithium, alkylmagnesium bromide, and alkylaluminum. Examples of suitable catalysts are stannous(II) 2-ethylhexanoate, also known as stannous octanoate, i.e., [Sn(Oct)2], aluminum triisopropoxide, and isopropoxide lanthanides.

[0062] Polycaprolactone may contain structure (IV) as a repeating motif, and the terminal groups depend on the initiator and / or catalyst used. [ka]

[0063] Polyhydroxyalkanoates (PHAs) as defined herein refer to polymers that can be classified as polyesters, preferably linear polyesters. Polyhydroxyalkanoates can be produced by bacterial fermentation of lipids and sugars, such as glucose. In some embodiments, polyhydroxyalkanoates can be produced by biosynthesis. In some embodiments, polyhydroxyalkanoates are biodegradable.

[0064] Polypropylene carbonate (PPC) as defined herein refers to a copolymer of carbon dioxide and propylene oxide. The polymer is thermoplastic and is typically formed using zinc glutarate as a catalyst during polymerization. The repeating motif of PPC can be represented by structure (V). [ka]

[0065] In some embodiments, the indicator is a color indicator. This has the advantage that consumers or users of the polymer composition or article can determine the degree of depolymerization using their own vision. Therefore, no further apparatus may be required to obtain an initial indication of the degree of depolymerization. The change in color may make it easier to obtain an accurate measurement of the degree of depolymerization when an apparatus is used, and may allow non-conventional apparatus such as a spectrometer to be used to determine the degree of depolymerization.

[0066] In some embodiments, the indicator is a pH indicator, a complex titration indicator, a redox indicator, a temperature indicator, or a hydrolysis indicator.

[0067] In some embodiments, the indicator is a pH indicator, preferably a halochromic indicator. These indicators can be used, for example, with polymers whose acidity changes upon depolymerization. This change in acidity may be due to acidic or basic functional groups formed by the depolymerization of the polymer. For example, many polycondensates produce -COO upon depolymerization. - A group is formed, which causes a change in acidity. pH indicators can be used to visualize these changes in acidity. In particular, pH indicators can be used for polycondensation polymers, preferably polyesters, to indicate the degree of depolymerization.

[0068] In some embodiments, the indicator is responsive to changes in the concentration of hydrogen ions in the polymer composition or article.

[0069] In some embodiments, the equivalence point of the pH indicator is located at pH 2.0 to pH 12.0, preferably pH 3.0 to pH 11.0, preferably pH 4.0 to pH 10.0, preferably pH 5.0 to pH 9.0, and preferably pH 6.0 to pH 8.0.

[0070] In some embodiments, the color transition range of the indicator is less than pH 7.00, preferably less than pH 6.50, preferably less than pH 6.00, and preferably less than pH 5.50. These indicators are particularly interesting for biodegradable polymers that become acidic during degradation.

[0071] In some embodiments, the pKa of the base and / or buffer is higher than the color transition range of the indicator. Here again, this is of particular interest for biodegradable polymers that acidify during degradation. Due to the higher pKa of the base, neutralization with the base occurs first during degradation, followed by a decrease in pH and a change in the indicator's color. In this way, the moment of color change can be delayed, allowing more degradation to occur before the color change.

[0072] In some embodiments, the indicator is a natural or synthetic indicator, preferably selected from a list including cresol red, methyl red, bromocresol purple, bromocresol green, chlorophenol, resazurin, bromothymol blue, xylenol, curcumin, alizarin, shikonin, betalain, flavonoids, and anthocyanins, or combinations thereof. Preferably, the indicator is a natural indicator.

[0073] In some embodiments, the indicator is resazurin, also known as 7-hydroxy-3H-phenoxazine-3-one 10-oxide (=structure (VI)). Resazurin exhibits a blue to purple color at pH > 6.5 and can be irreversibly reduced to resorphine (7-hydroxy-3H-phenoxazine-3-one), which is pink and highly fluorescent. At near-neutral pH, resorphine can be detected by visual observation of its pink color or by fluorescence assay, with excitation maximums at 530 nm to 570 nm and emission maximums at 580 nm to 590 nm. [ka]

[0074] In some embodiments, the indicator is anthocyanin. As used herein, the term “anthocyanin” may refer to a flavonoid compound formed from a glycosylated polyhydroxy or polymethoxy derivative of 2-phenylchromene. This is a natural colorant that reflects red to blue light in the visible spectrum, particularly depending on the pH.

[0075] In some embodiments, the indicator is curcumin, a molecule that can exist in either the keto form (structure VIIa) or the enol form (structure VIIb). Under polar, acidic, and neutral conditions, the keto form is dominant and is yellow. On the other hand, under nonpolar and alkaline conditions, particularly at pH > 8, the enol form is dominant and is red. [ka]

[0076] Curcumin can also be used, for example, as an indicator for complex titrations of boron. Curcumin reacts with boric acid to form a red compound.

[0077] In some embodiments, the indicator is alizarin, also known as 1,2-dihydroxyanthraquinone, which can be represented by structure (VIII). The color of alizarin can change from yellow to purple depending on the pH conditions. [ka]

[0078] In some embodiments, the indicator may be a betalain. As used herein, the term “betalain” may be understood as a type of red and yellow tyrosine-derived pigment found in plants of the Caryophyllales order. There are two categories of betalains. Betacyanins contain betalain pigments ranging in color from reddish to purple. Betanin, isobetanin, probetanin, and neobetanin are examples of betacyanins. Betaxanthins contain betalain pigments ranging in color from yellowish to orange. Examples of betaxanthins include bulgaxanthin, milaxanthin, portulacaxanthin, and indicaxanthin.

[0079] In some embodiments, the indicator may be betanine, which can be represented by structure (IX). [ka]

[0080] In some embodiments, the indicator may be miraxanthin-II, which is an example of miraxanthin. Miraxanthin-II can be represented by structure (X). [ka]

[0081] In some embodiments, the indicator may be shikonin, also known as (±)-5,8-dihydroxy-2-(1-hydroxy-4-methyl-3-pentenyl)-1,4-naphthoquinone. The color of shikonin can vary over a pH range of 2 to 12, starting from red at pH 2, through purple around pH 7, and up to blue at pH 12. Shikonin can be represented structurally by (XI). [ka]

[0082] In some embodiments, the indicator is a nitrophenyl ester or a derivative thereof, preferably a nitrophenyl acetate or a derivative thereof, preferably p-nitrophenyl acetate represented by formula (XII), or a derivative thereof. [ka]

[0083] Upon hydrolysis of the ester, the colorless p-nitrophenyl acetate (XII) is converted to yellow p-nitrophenol (XIII). [ka]

[0084] In particular, nitrophenyl esters can be incorporated into the main chains of polymers such as PLA and PCL. Examples of such incorporation are shown in Figure 1, where the incorporation of 4-(carboxyacetoxy)benzoic acid, 3-hydroxy-5-nitrobenzoic acid, 4-amino-3-nitrophenol, 2-nitrobenzene-1,3-diol, and 4,6-dinitroresorcinol into PLA and PCL is shown, respectively. During the degradation of PLA or PCL polymers, these compounds are released, resulting in a color change that indicates the degree of degradation.

[0085] According to some embodiments of the present invention, the indicator is responsive to changes in ion concentration, temperature, oxidation-reduction potential, and / or hydrolysis conditions.

[0086] In some embodiments, the indicator is a complex titration indicator. Examples of such complex titration indicators are: Calcein and Patton-Reeder indicator when the analyte is calcium. When the analyte is boron, curcumin Eriochrome Black T when the analyte is aluminum, cadmium, zinc, calcium, or magnesium. Fast Sulphon Black when the analyte is copper, That is the case.

[0087] In some embodiments, polymer compositions may contain a complex titration indicator in their complex with their analytes. Upon decomposition of the polymer, the complex becomes accessible to the environment, which can remove the analytes from the complex with the complex titration indicator, potentially causing a change in appearance.

[0088] In some embodiments, the indicator is a redox indicator. Redox indicators can be used with hydrophobic polymers, where hydrogen ions are revealed by decomposition in a non-aqueous environment. For example, methylene blue can be used as an indicator involved in a redox reaction in which hydrogen ions cause a color change.

[0089] In some embodiments, the indicator is a temperature indicator. In some embodiments, the polymer composition comprises a temperature indicator and a thermal radical initiator such as an azo compound and peroxide, e.g., azobisisobutyronitrile (AIBN), 1,1'-azobis(cyclohexanecarbonile) (ACHN), di-tert-butyl peroxide, benzoyl peroxide, or methyl ethyl ketone peroxide. The thermal radical initiator splits into radicals upon heating, and these radicals can promote decomposition and depolymerization. A change in the appearance of the temperature indicator is thought to indicate or characterize heating of the polymer that initiates the radicals, and that decomposition is occurring.

[0090] In some embodiments, the indicator is a hydrolysis indicator. As used herein, the term “hydrolysis indicator” may refer to a compound whose appearance changes when a bond is hydrolyzed. Preferably, the hydrolysis indicator contains an ester bond, an amide bond, or a glycosidic bond, and preferably contains an ester bond that changes the appearance of the indicator upon hydrolysis. Examples of hydrolysis indicators are p-nitrophenyl acetate (sensitive to deesterification), fluorescein diacetate (sensitive to deesterification), and resolphin β-D-glucuronide (sensitive to glycosidic cleavage).

[0091] In some embodiments, the indicator may be resorphine β-D-glucuronide, which can be represented by structure (XV), which is orange in color. Cleavage of the glycosidic bond releases resorphine (structure XVI), which is bright pink. This indicator may be of particular interest for indicating the degree of depolymerization in polysaccharide-based polymers and polymer compositions. [ka]

[0092] In some embodiments, the indicator may be a colorless fluorescein diacetate, which may be represented by structure (XVII). Deesterification releases fluorescein, which may be represented by green structure (XVIII). [ka]

[0093] In some embodiments, the indicator is a dye in which at least one hydroxyl functional group is esterified, preferably acetylated, and the cleavage of the ester bond causes a color change.

[0094] In some embodiments, the indicator is a halochromic indicator or an ionochromic indicator, preferably a halochromic indicator.

[0095] In some embodiments, the indicator is chemically or physically incorporated into the polymer composition.

[0096] As used herein, the term “chemical formulation” is understood to mean, preferably, the process of producing a formulation of an additive with a polymer, oligomer, or monomer, in which the additive chemically reacts with the polymer, oligomer, or monomer during or after polymerization. Thus, the additive in the resulting chemical formulation can be incorporated into the polymer backbone, covalently bonded to the polymer side chains, or react with one or both ends of the polymer chain. The advantage of chemical formulations may be that the additive, or more specifically the indicator, is chemically bonded to the polymer, thus preventing the leaching of the additive from the polymer in the polymer composition. To facilitate chemical formulation, it may be necessary to introduce reactive groups into the initiators disclosed herein. For example, hydroxide groups, carboxylic acid groups, or amine groups can be introduced into the initiator to be incorporated into the polymer via esterification or amide bond formation.

[0097] As used herein, the term “physical formulation” is preferably, The polymer and the additive are preferably mechanically mixed together in the molten phase of the polymer. solution mixing, It is understood as a process for producing polymer formulations.

[0098] One advantage of physical formulation is that it is easier to form because the reactive groups sometimes required in chemical formulation do not need to be present on the additives.

[0099] In some embodiments, the indicator is chemically incorporated into the polymer composition, preferably by copolymerization. Preferably, the indicator is chemically incorporated into a biodegradable polymer, preferably by copolymerization. Chemical incorporation makes the indicator less likely to leach.

[0100] Preferably, in some embodiments, the indicator is incorporated into the polymer composition or biodegradable polymer via at least one hydrolyzable bond, preferably the indicator is a hydrolysis indicator, and more preferably the biodegradable polymer is a polycondensate such as polyester or polyamide, preferably polyester. When such a polymer is depolymerized, for example by hydrolase, the hydrolyzable bond linking the hydrolysis indicator to the polymer is cleaved, and the hydrolysis indicator will subsequently change in appearance, preferably color.

[0101] In some embodiments, the biodegradable polymer is a polycondensed polymer, preferably polyester, polyamide, polyimide, polyacetal, polyurethane, polycarbonate, or a randomized or block copolymerized mixture thereof, and preferably the biodegradable polymer is polyester.

[0102] In some embodiments, the biodegradable polymer includes ester bonds, amide bonds, acetal bonds, and / or urethane bonds.

[0103] In some embodiments, the biodegradable polymer is PLA, PCL, or a randomized or block copolymerized mixture thereof.

[0104] In some embodiments, the polymer composition is The above indicator is present in an amount of at least 0.01% by weight and at most 10.00% by weight, 0.00% by weight to a maximum of 25.00% by weight of a base, buffer, or mixture thereof, preferably a base and At least 65.00% by weight to a maximum of 99.99% by weight of the above-mentioned biodegradable polymer, preferably a biodegradable polymer as defined herein, Includes.

[0105] The presence of a base can compensate for pH changes caused by the initial polymer matrix and by a tolerable amount of depolymerization. In this way, the degree of depolymerization can be manipulated so that the appearance of an indicator, preferably a pH indicator, changes. This is useful, for example, for polymer compositions and articles that allow a certain degree of depolymerization until certain properties or qualities are lost.

[0106] The present invention can also provide a polymer composition or an article containing the polymer composition, preferably a self-directing biodegradable polymer or a self-directing biodegradable polymer composition, wherein the polymer composition is At least 0.01% by weight to a maximum of 10.00% by weight of the above indicator, preferably a hydrolysis indicator, At least 0.00% by weight to a maximum of 25.00% by weight of a base, buffer, or mixture thereof, preferably a base and At least 65.00% by weight to a maximum of 99.99% by weight of a biodegradable polymer, preferably a biodegradable polymer as defined herein, Includes.

[0107] More specifically, the present invention may also provide a polymer composition or an article containing the polymer composition, the polymer composition is The above indicator is present in an amount of at least 0.01% by weight and at most 10.00% by weight, At least 0.05% by weight to a maximum of 25.00% by weight of a base, buffer, or mixture thereof, preferably a base and At least 65.00% by weight to a maximum of 99.94% by weight of a biodegradable polymer, preferably a biodegradable polymer as defined herein, Includes.

[0108] In some embodiments, the polymer composition or biodegradable polymer contains the indicator in an amount of at least 0.01% by weight to a maximum of 10.00% by weight, preferably at least 0.05% by weight to a maximum of 9.50% by weight, preferably at least 0.10% by weight to a maximum of 9.00% by weight, preferably at least 0.20% by weight to a maximum of 8.00% by weight, preferably at least 0.50% by weight to a maximum of 7.00% by weight, preferably at least 0.70% by weight to a maximum of 6.00% by weight, preferably at least 1.00% by weight to a maximum of 5.00% by weight, preferably at least 1.50% by weight to a maximum of 4.00% by weight, and preferably at least 2.00% by weight to a maximum of 3.00% by weight.

[0109] In some embodiments, the polymer composition or biodegradable polymer contains the indicator in an amount of at least 0.01% by weight, preferably at least 0.05% by weight, preferably at least 0.10% by weight, preferably at least 0.20% by weight, preferably at least 0.50% by weight, preferably at least 0.70% by weight, preferably at least 1.00% by weight, preferably at least 1.50% by weight, and preferably at least 2.00% by weight.

[0110] In some embodiments, the polymer composition contains a base, a buffer, or a mixture thereof, preferably a base, in an amount of at least 0.10% to a maximum of 25.00% by weight, preferably at least 0.20% to a maximum of 20.00% by weight, preferably at least 0.50% to a maximum of 15.00% by weight, preferably at least 0.70% to a maximum of 10.00% by weight, preferably at least 1.00% to a maximum of 7.00% by weight, preferably at least 1.50% to a maximum of 5.00% by weight, and preferably at least 2.00% to a maximum of 3.00% by weight.

[0111] In some embodiments, the polymer composition contains a biodegradable polymer, preferably a biodegradable polymer as defined herein, in an amount of at least 65.00% to a maximum of 99.99% by weight, preferably at least 67.00% to a maximum of 99.95% by weight, preferably at least 68.00% to a maximum of 99.90% by weight, preferably at least 70.00% to a maximum of 99.00% by weight, preferably at least 75.00% to a maximum of 98.00% by weight, preferably at least 80.00% to a maximum of 95.00% by weight, and preferably at least 85.00% to a maximum of 90.00% by weight.

[0112] In some embodiments, the polymer composition comprises at least 65.00% by weight, preferably at least 70.00% by weight, preferably at least 75.00% by weight, preferably at least 80.00% by weight, and preferably at least 85.00% by weight of a biodegradable polymer, preferably a biodegradable polymer as defined herein.

[0113] In some embodiments, the base is selected from a list including NaOH, KOH, Ca(OH)2, CsOH, RbOH, Mg(OH)2, LiOH, Sr(OH)2, Br(OH)2, Na2CO3, NaHCO3, NH4OH, urea, histamine, or mixtures thereof, preferably from a list including NaOH, Na2CO3, NaHCO3, NH4OH, urea, histamine, or mixtures thereof. In some embodiments, the base is an inorganic base.

[0114] In some embodiments, the buffer is one of Good's buffers, which includes MES, ADA, PIPES, ACES, MOPSO, coramine chloride, MOPS, BES, TES, HEPES, DIPSO, TAPSO, acetamidoglycine, POPSO, HEPPSO, HEPPS, tricine, tris, glycinamide, glycylglycine, bicine, and TAPS.

[0115] The present invention further includes a method for visualizing depolymerization in a polymer composition or an article containing a polymer composition, the method being A step of incorporating an indicator into a polymer composition, preferably to obtain a polymer composition as defined herein, Optionally, a step of forming an article from a polymer composition, Includes.

[0116] In some embodiments, the method further includes the step of incorporating a base into the polymer composition. Preferably, the amount of base depends on the initial pH of the new polymer matrix and, optionally, the allowable amount of depolymerization until depolymerization is indicated by an indicator.

[0117] More specifically, the present invention provides a method for visualizing depolymerization in a polymer composition or an article containing a polymer composition, the method being: A step of incorporating an indicator into a polymer composition, preferably in an amount of at least 0.01% by weight to a maximum of 10.00% by weight relative to the total weight of the polymer composition, A step of incorporating a base, buffer, or mixture thereof into a polymer composition, preferably in an amount of at least 0.05% by weight to a maximum of 25.00% by weight relative to the total weight of the polymer composition, Optionally, a step of forming an article from a polymer composition, Includes.

[0118] As used herein, the term “incorporate” should preferably be understood to encompass both physical and chemical formulations.

[0119] The present invention further provides a self-indicating, biodegradable polymer in which an indicator is chemically incorporated into or in a biodegradable polymer, preferably a biodegradable polymer.

[0120] In some embodiments of self-degrading polymers, the indicator is a hydrolysis indicator that is chemically incorporated into or in the biodegradable polymer via at least one ester or amide bond, preferably an ester bond. The indicator may be incorporated into the polymer backbone, bonded to side chains, or bonded to the end caps of the polymer.

[0121] In some embodiments of the self-directing decomposition polymer, nitrophenyl esters may be included.

[0122] In some embodiments of the self-directing decomposition polymer, the decomposition polymer is preferably a polycondensate, more preferably a polymer selected from a list including polylactic acid (PLA), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polypropylene carbonate (PPC), or mixtures thereof.

[0123] In some embodiments of self-directing decomposition polymers, the indicator chemically incorporated into or in the decomposition polymer may be a compound having the structures (I1) to (I5) provided below.

[0124] In some embodiments, the self-directing decomposition polymer may be a polymer that can be represented by the structures (PLA1) to (PLA5) or (PCL1) to (PCL5) provided below.

[0125] It should be understood that certain embodiments of use also include embodiments of polymer compositions, methods, and self-directing biodegradable polymers, and vice versa.

[0126] Further aspects of the present invention may be any combination of the following numbered descriptions. 1. Use of an indicator to show the degree of depolymerization, preferably biodegradability, of a degradable polymer in a polymer composition or an article made from the polymer composition, wherein the change in the appearance of the indicator is caused by the depolymerization of the degradable polymer. The indicator is used by being chemically incorporated into a polymer composition, preferably copolymerized, and more preferably chemically incorporated into a biodegradable polymer. 2. Use as described in Description 1, where the indicator is a color indicator. 3. Use as described in description 1 or 2, wherein the indicator is a pH indicator, a complex titration indicator, a redox indicator, a temperature indicator, or a hydrolysis indicator. 4. The use described in any of descriptions 1 to 3, wherein the indicator is a halochromic indicator or an ionochromic indicator, preferably a halochromic indicator. 5. Use according to any one of descriptions 1 to 4, wherein the color transition range of the indicator is less than pH 7.00, preferably less than pH 6.50, preferably less than pH 6.00, preferably less than pH 5.50. 6. Use according to any one of descriptions 1 to 5, wherein the degradable polymer is a biodegradable polymer, preferably a polymer that can be composted at home. 7. Use according to any one of descriptions 1 to 6, wherein the polymer is a polycondensed polymer, preferably polyester, polyamide, polyimide, polyacetal, polyurethane, polycarbonate, or a mixture thereof, and preferably the polymer is polyester. 8. The use according to any one of descriptions 1 to 7, wherein the indicator is responsive to changes in the concentration of hydrogen ions in the polymer composition or an article made from the polymer composition. 9. Use as described in any of descriptions 1 to 8, wherein the indicator is a natural or synthetic indicator, preferably selected from the list including cresol red, methyl red, bromocresol purple, bromocresol green, chlorophenol, resazurin, bromothymol blue, xylenol, curcumin, alizarin, shikonin, betalain, flavonoids, and anthocyanins and / or derivatives thereof, preferably copolymerizable derivatives. 10. Use as described in any of descriptions 1 to 9, wherein the indicator is responsive to changes in ion concentration, temperature, oxidation-reduction potential, and / or hydrolysis conditions. 11. A polymer composition or an article containing the polymer composition, wherein the polymer composition is At least 0.05% by weight to a maximum of 25.00% by weight of cushioning material, At least 75.00% by weight to a maximum of 99.95% by weight of biodegradable polymers, Includes, A polymer composition or article comprising a degradable polymer containing an indicator suitable for indicating the degree of depolymerization, preferably suitable for indicating the degree of biodegradation, wherein the indicator is chemically incorporated into the polymer composition, preferably copolymerized, and more preferably chemically incorporated into the degradable polymer. 12. The polymer composition according to description 11, wherein at least 0.01% by weight and at most 10.00% by weight of an indicator is chemically incorporated into the biodegradable polymer, the weight percentage being expressed relative to the total weight of the polymer composition. 13. A method for visualizing depolymerization in a polymer composition or an article containing a polymer composition, wherein the polymer composition includes a degradable polymer, preferably a biodegradable polymer. The method is A step of chemically incorporating an indicator into a polymer composition, preferably a biodegradable polymer, preferably by copolymerization, Optionally, a step of forming an article from a polymer composition, Methods that include... 14. A self-indicating, biodegradable polymer in which an indicator is chemically incorporated into or in a biodegradable polymer, preferably a biodegradable polymer. 15. The self-indicating biodegradable polymer according to description 14, wherein the indicator is a hydrolysis indicator and the biodegradable polymer is a polycondensate, preferably polyester or polyamide, more preferably polyester. 16. Use of an indicator for indicating the degree of depolymerization, preferably biodegradability, of a degradable polymer in a polymer composition or an article made from the polymer composition, wherein the change in the appearance of the indicator is caused by the depolymerization of the degradable polymer. 17. Use as described in description 16, where the indicator is a color indicator. 18. Use as described in description 2 or 16, wherein the indicator is a pH indicator, a complex titration indicator, a redox indicator, a temperature indicator, or a hydrolysis indicator. 19. The use described in any of descriptions 3 to 16, wherein the indicator is chemically or physically incorporated into the polymer composition. 20. The use according to any one of descriptions 4 to 16, wherein the indicator is chemically incorporated into the polymer composition, more preferably into a biodegradable polymer, and preferably copolymerized. 21. The use according to any one of descriptions 5 to 16, wherein the indicator is a halochromic indicator or an ionochromic indicator, preferably a halochromic indicator. 22. Use according to any one of descriptions 6 to 16, wherein the degradable polymer is a biodegradable polymer, preferably a polymer that can be composted at home. 23. Use according to any one of descriptions 7 to 16, wherein the polymer is a polycondensation polymer, preferably polyester, polyamide, polyimide, polyacetal, polyurethane, polycarbonate, or a mixture thereof, and preferably the polymer is polyester. 24. The use according to any one of descriptions 8 to 16, wherein the indicator is responsive to a change in the concentration of hydrogen ions in the polymer composition or an article made from the polymer composition. 25. Use as described in any of descriptions 9 to 16, wherein the indicator is a natural or synthetic indicator, preferably selected from the list including cresol red, methyl red, bromocresol purple, bromocresol green, chlorophenol, resazurin, bromothymol blue, xylenol, curcumin, alizarin, shikonin, betalain, flavonoids, and anthocyanins, or combinations thereof. 26. Use as described in any of descriptions 8 to 16, wherein the indicator is responsive to changes in ion concentration, temperature, oxidation-reduction potential, and / or hydrolysis conditions. 27. A polymer composition or an article containing the polymer composition, wherein the polymer composition is An indicator that shows the degree of depolymerization, preferably the degree of biodegradation, in an amount of at least 0.01% by weight to a maximum of 10.00% by weight, At least 0.05% by weight to a maximum of 25.00% by weight of cushioning material, At least 65.00% by weight to a maximum of 99.99% by weight of biodegradable polymers, A polymer composition or article containing the following: 28. A method for visualizing depolymerization in a polymer composition or an article containing a polymer composition, A step of incorporating an indicator into a polymer composition, Optionally, a step of forming an article from a polymer composition, Methods that include... 29. A self-indicating, biodegradable polymer in which an indicator is chemically incorporated into or in a biodegradable polymer, preferably a biodegradable polymer. 30. The self-indicating biodegradable polymer according to description 29, wherein the indicator is a hydrolysis indicator and the biodegradable polymer is a polycondensate, preferably a polyester or polyamide, more preferably a polyester. [Examples]

[0127] Example 1: In this embodiment, several indicator derivatives (I1-I5) are disclosed that can be chemically compounded with PLA or PCL to form the corresponding PLA1-PLA5 or PCL1-PCL5. The indicator derivatives (I1-I5) are derived from p-nitrophenyl acetate (=structure (XII)), which is colorless in the presence of an acetate group and becomes yellow when the acetate group is removed after hydrolysis of the ester bond, forming p-nitrophenol (=structure (XIII)), which is yellow. [ka] TIFF2026509354000017.tif107170

[0128] In PLA1 and PCL1, indicator I1 is chemically incorporated into the polymer as a terminal cap via esterification. In PLA2-PLA5 and PCL2-PCL5, indicators I2-I5 are chemically incorporated into the polymer main chain via esterification for I2, I4, and I5, or via esterification and amide bond formation for I3.

[0129] These polymers PLA1-PLA5 or PCL1-PCL5 decompose and depolymerize by hydrolysis of the ester bonds in the polymer backbone. Therefore, hydrolysis of the ester bonds adjacent to the nitrophenyl portion in the polymer backbone causes a color change from colorless to yellow, which indicates the depolymerization of the decomposable polymers PLA1-PLA5 or PCL1-PCL5.

[0130] Example 2: Bromocresol green (BCG) (=structure XIV) is a compound in which, Yellow at a pH below 3.8. At a pH of 3.8 to 5.4, it turns green, and Blue at pH levels above 5.4. Therefore, it can act as a pH indicator or a halochromic indicator. [ka]

[0131] Bromocresol green was extruded in a 1% by weight quantity with 1.00% by weight of NaOH into an Ingevity PCLCAPA 6250 using a Filafab extruder at 120°C for a residence time of approximately 3 minutes. The extruded filament was blue in color.

[0132] The extruded filament was cut into five different fragments, and four of these fragments were subjected to enzymatic digestion with a different enzyme. A fifth fragment of the filament was used as a control experiment using only water and no enzymes, but was subjected to the same conditions as the other fragments during enzymatic digestion. As a negative control, four aliquots of silica powder containing 1% by weight bromocresol green and 1.00% by weight NaOH were also subjected to enzymatic digestion with four different enzymes. The results can be seen in Figure 2. Row 2A shows the filament fragments after enzymatic digestion at 40°C for 12 hours. Row 2B shows the same filament fragment as row 2A after further enzymatic digestion (digestion) at 37°C for 48 hours. Row 2C shows a negative control that underwent similar enzymatic digestion, using silica powder instead of a biodegradable polymer.

[0133] Since Figure 2 is provided in black and white, please note that in reality, the color changes from blue (B=bright blue, b=pale blue) through green (G=bright green, g=pale green) to yellow (Y=bright yellow, y=pale yellow). Items labeled "weg" mean "gone" in Dutch, and indicate that the filament has been completely digested.

[0134] Example 3: Bromocresol green was extruded in 2% by weight of NatureWorks® PLA Ingeo® 6302D with 1.00% by weight of NaOH using a TRUUS extruder at 140°C for a residence time of approximately 2.5 minutes. The extruded powder was blue in color and changed to yellow in an aqueous solution at pH 4.

[0135] Example 4: Bromocresol green was extruded in PBS at a concentration of 4 wt% with 1.00 wt% Na2CO3 using a TRUUS extruder at 140°C for a residence time of approximately 2.5 minutes. The extruded fragment was blue in color and changed to yellow in an aqueous solution at pH 4.

Claims

1. A polymer composition or an article containing the polymer composition, The polymer composition is An indicator that shows the degree of depolymerization, preferably the degree of biodegradation, in an amount of at least 0.01% by weight to a maximum of 10.00% by weight, At least 0.05% by weight to a maximum of 25.00% by weight of a base, buffer, or mixture thereof, A biodegradable polymer in an amount of at least 65.00% by weight and at most 99.94% by weight, A polymer composition or article containing the following:

2. The polymer composition or article according to claim 1, wherein the polymer composition contains at least 0.05% by weight to a maximum of 25.00% by weight of a base.

3. where the base is selected from the list comprising NaOH, KOH, Ca(OH) ２ , CsOH, RbOH, Mg(OH) ２ , LiOH, Sr(OH) ２ , Br(OH) ２ , Na ２ CO ３ , NaHCO ３ , NH ４ OH, urea, histamine, or a mixture thereof, preferably selected from the list comprising NaOH, Na ２ CO ３ , NaHCO ３ , NH ４ OH, urea, histamine, or a mixture thereof, the polymer composition or article according to claim 1 or 2.

4. The polymer composition or article according to any one of claims 1 to 3, wherein the base is an inorganic base.

5. The polymer composition or article according to any one of claims 1 to 4, wherein the indicator is a color indicator.

6. The polymer composition or article according to any one of claims 1 to 5, wherein the indicator is a pH indicator, preferably a halochromic indicator.

7. The polymer composition or article according to any one of claims 1 to 6, wherein the indicator is a natural or synthetic indicator, preferably selected from the list including cresol red, methyl red, bromocresol purple, bromocresol green, chlorophenol, resazurin, bromothymol blue, xylenol, curcumin, alizarin, shikonin, betalain, flavonoids, and anthocyanins, or combinations thereof.

8. The polymer composition or article according to any one of claims 1 to 7, wherein the color transition range of the indicator is less than pH 7.00, preferably less than pH 6.50, preferably less than pH 6.00, and preferably less than pH 5.

50.

9. The polymer composition or article according to any one of claims 1 to 8, wherein the pKa of the base and / or the buffer is higher than the color transition range of the indicator.

10. The polymer composition or article according to any one of claims 1 to 9, wherein the indicator is chemically or physically incorporated into the polymer composition.

11. The polymer composition or article according to any one of claims 1 to 10, wherein the indicator is chemically incorporated into the polymer composition, more preferably into the biodegradable polymer, and preferably copolymerized.

12. The polymer composition or article according to any one of claims 1 to 11, wherein the degradable polymer is a biodegradable polymer, preferably a polymer that can be composted at home.

13. The polymer composition or article according to any one of claims 1 to 12, wherein the polymer is a polycondensation polymer, preferably polyester, polyamide, polyimide, polyacetal, polyurethane, polycarbonate, or a mixture thereof, and preferably the polymer is polyester.

14. A method for visualizing depolymerization in a polymer composition or an article containing the polymer composition, The process involves incorporating an indicator into the polymer composition, preferably in an amount of at least 0.01% by weight to a maximum of 10.00% by weight relative to the total weight of the polymer composition. The process involves incorporating a base, a buffer, or a mixture thereof into the polymer composition, preferably in an amount of at least 0.05% by weight to a maximum of 25.00% by weight relative to the total weight of the polymer composition. Optionally, a step of forming an article from the polymer composition, Methods that include...

15. The method according to claim 14, wherein the base, buffer, or mixture thereof is incorporated into the polymer composition by chemical or physical compounding, preferably by extrusion.

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