Method for recycling polystyrene materials containing brominated contaminants

Abstract

The present disclosure relates to a method for removing brominated contaminants and recovering brominated contaminants from polystyrene waste. The present disclosure further relates to a method for recycling polystyrene waste, where recycling includes retention of brominated contaminants or removal of contaminants. The present disclosure also relates to the use of monocyclic aromatic benzene-based solvents in removing and / or recovering brominated contaminants from polystyrene waste and recycling polystyrene waste. Furthermore, the present disclosure relates to the use of recovered brominated contaminants in the manufacture of polystyrene products such as insulation.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 278,482, filed November 11, 2021, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THEINVENTION The present disclosure relates to a method for recycling polystyrene waste containing brominated contaminants, including brominated polymeric flame retardants. The present disclosure also relates to a method for removing brominated contaminants from polystyrene waste. [Background technology]

[0003] Introduction Post-consumer polystyrene waste is routinely recycled to obtain recycled polystyrene material that can be reused. Polystyrene waste, such as expanded or extruded polystyrene (EPS or XPS) insulation, often contains brominated flame retardants that are difficult to remove from the polystyrene waste, making recycled polystyrene less desirable. For example, hexabromocyclododecane (HBCD) was commonly used as a flame retardant in polystyrene insulation until it was recently banned in Europe and other countries due to health hazards. The hydrophobic nature of HBCD makes its removal from polystyrene difficult. Additionally, brominated polymeric flame retardants (PFRs), including brominated polybutadiene polystyrene copolymers, present unique challenges in recycling polystyrene due to the inherent affinity of PFRs for polystyrene polymers and polystyrene copolymers. Even with polystyrene waste that does not initially contain brominated contaminants, removal problems persist because batches of polystyrene waste are often cross-contaminated due to handling during waste management and / or during the recycling process.

[0004] At the same time, cases arise where it is desirable to retain the PFR in recycled polystyrene, for example, when it is known that the recycled polystyrene will be reused for a purpose requiring the PFR, such as insulation material. Retaining the PFR in such cases provides an opportunity for cost savings.

[0005] Therefore, there is a need to develop a method of recycling polystyrene waste that allows its use to be selective about the retention and removal of PFR. Summary of the Invention

[0006] Monocyclic aromatic (benzene-based) solvents that allow for the reuse of polystyrene waste via a dissolution / precipitation process have been shown to have different solubilities for PFRs. For example, 1 or 2 C 1 ~C 4 Solvents such as benzene substituted with alkyl substituents, at least one of which is isopropyl (e.g., cumene and p-cymene), and about 30% by weight of C 6 ~C 7 A hydrocarbon solvent and about 70% by weight of benzene or C 1 and C 2 benzene (e.g., toluene, p-xylene, ethylbenzene, p-ethyltoluene) substituted with one or two substituents each selected from alkyl, or about 70% by weight of one or two C 1 ~C 4 Mixtures of solvents containing benzene substituted with alkyl substituents are unable to solubilize PFR, whereas benzene, benzene-based solvents, and mixtures of benzene or benzene-based solvents with about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent remain suitable solvents for solubilizing polystyrene.

[0007] At the same time, the use of benzene, benzene-based solvents, and mixtures of solvents allows for the removal of other impurities, additives, and / or fillers present in the polystyrene.

[0008] Thus, in one aspect, the present disclosure provides a method for removing brominated polybutadiene polystyrene copolymer from polystyrene waste, comprising the steps of: Polystyrene waste, C 1 ~C 4 a second solvent selected from benzene substituted with 1-4, optionally 1 or 2, substituents each selected from alkyl, where at least one of the 1-4 substituents is isopropyl, a mixture of solvents comprising about 45% to about 95% by weight of the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent, and combining the mixtures to obtain a polystyrene / second solvent mixture and a solid comprising a copolymer, wherein the hydrocarbon polystyrene non-solvent is selected from C 5 ~C 8 and obtaining a hydrocarbon. and separating the copolymer-containing solids from the polystyrene / second solvent mixture; The first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof.

[0009] In another aspect, the present disclosure provides a method for removing brominated polybutadiene polystyrene copolymer from polystyrene waste, comprising: Polystyrene waste, C 1 ~C 4 a second solvent selected from benzene substituted with 1-4, optionally 1 or 2, substituents each selected from alkyl, where at least one of the 1-4 substituents is isopropyl, a mixture of solvents comprising about 45% to about 95% by weight of benzene or the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent, and combining the mixtures to obtain a polystyrene / second solvent mixture and a solid comprising a copolymer, wherein the hydrocarbon polystyrene non-solvent is selected from C 5obtaining a C1-C8 hydrocarbon, and separating the copolymer-containing solids from the polystyrene / second solvent mixture; The first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof.

[0010] In another aspect, the present disclosure provides a method for recycling polystyrene waste, comprising: Reclaiming includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When recycling includes retaining the copolymer, the method further comprises: Dissolving polystyrene waste in a first solvent to obtain a polystyrene / first solvent mixture, the first solvent being selected from the group consisting of C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; adding the polystyrene / first solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of 5 ~C 8 and obtaining a mixture thereof selected from the group consisting of hydrocarbons, separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the double washed polystyrene; When recycling includes removing the copolymer, the method further comprises: The polystyrene waste is dissolved in a second solvent, the second solvent being C 1 ~C 4 a mixture of solvents comprising about 45% to about 95% by weight of the first or second solvent defined above, and about 5% to about 55% by weight of the hydrocarbon polystyrene non-solvent defined above, and dissolving in said mixture a polystyrene / second solvent mixture, and a solid comprising the copolymer; separating a solid comprising the copolymer from the polystyrene / second solvent mixture; adding the polystyrene / second solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the dual washed polystyrene.

[0011] In another aspect, the present disclosure provides a method for recycling polystyrene waste, comprising: Reclaiming includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When recycling includes retaining the copolymer, the method further comprises: Dissolving polystyrene waste in a first solvent to obtain a polystyrene / first solvent mixture, the first solvent being selected from the group consisting of C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; adding the polystyrene / first solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of 5 ~C 8 and obtaining a mixture thereof selected from the group consisting of hydrocarbons, separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the double washed polystyrene; When recycling includes removing the copolymer, the method further comprises: The polystyrene waste is dissolved in a second solvent, the second solvent being C 1 ~C 4 a mixture of solvents comprising about 45% to about 95% by weight of the first or second solvent defined above, and about 5% to about 55% by weight of the hydrocarbon polystyrene non-solvent defined above, and dissolving in said mixture a polystyrene / second solvent mixture, and a solid comprising the copolymer; separating a solid comprising the copolymer from the polystyrene / second solvent mixture; combining the polystyrene / second solvent mixture with a first portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; Precipitated polystyrene, washing with a second portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent; or washing with a mixture of about 45% to about 95% by weight of a hydrocarbon polystyrene non-solvent and about 5% to about 55% by weight of the first solvent or the second solvent defined above, and the mixtures to obtain a washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; The washed polystyrene washing with a third portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent; or washing with a mixture of a third solvent comprising about 45% to about 95% by weight of a hydrocarbon polystyrene non-solvent and about 5% to about 55% by weight of the first solvent or the second solvent defined above, and the mixtures thereof to obtain a double washed polystyrene and a third portion of the hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; and drying the dual washed polystyrene.

[0012] In another aspect, the present disclosure provides a method for recovering a carbonaceous additive from polystyrene waste, the method comprising: dissolving the polystyrene waste in a mixture of solvents comprising a second solvent, about 45% to about 95% by weight of the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent, and mixtures thereof to obtain a solid comprising a polystyrene / second solvent mixture and a carbonaceous additive; separating the polystyrene / second solvent mixture and the solids including the carbonaceous additive; washing the solid containing the carbonaceous additive with a first solvent to obtain a carbonaceous additive and a first solvent solution; and optionally drying the carbonaceous additive; The first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; The second solvent is C 1 ~C 4 benzene substituted with one or two substituents each selected from alkyl, wherein at least one of the one or two substituents is isopropyl; Hydrocarbon polystyrene non-solvent, C 5 ~C 8 The process includes a method in which the hydrocarbon is selected from the group consisting of benzene, toluene ...

[0013] In another aspect, the present disclosure provides the use of a second solvent in the removal of a brominated polybutadiene polystyrene copolymer, comprising: The second solvent is C 1 ~C 4 benzene substituted with one or two substituents each selected from alkyl, at least one of the one or two substituents being isopropyl; the mixture of solvents comprising from about 45% to about 95% by weight of the first solvent or the second solvent, and from about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent; and mixtures thereof; The first solvent is selected from benzene substituted with one or two substituents each selected from C1 and C2 alkyl, and mixtures thereof.

[0014] In another aspect, the present disclosure provides the use of a second solvent in the recovery of a brominated polybutadiene polystyrene copolymer, comprising: the second solvent is selected from benzene substituted with one or two substituents each selected from C1-C4 alkyl, at least one of the one or two substituents being isopropyl; the mixture of solvents comprises about 45% to about 95% by weight of the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent; and mixtures thereof; The first solvent is selected from benzene substituted with one or two substituents each selected from C1 and C2 alkyl, and mixtures thereof.

[0015] In another aspect, the present disclosure includes the use of the brominated polybutadiene polystyrene copolymer recovered from the process of the present disclosure in the production of a polystyrene product, optionally wherein the polystyrene product is a thermal insulation material.

[0016] In another aspect, the present disclosure includes the use of a carbonaceous additive recovered from polystyrene waste by the method of the present disclosure in the production of a polystyrene product, optionally wherein the product is a thermal insulation material.

[0017] In another aspect, the present disclosure provides a method for recycling polystyrene waste, comprising: Reclaiming includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When recycling includes retaining the copolymer, the method further comprises: Dissolving polystyrene waste in a first solvent to obtain a polystyrene / first solvent mixture, the first solvent being selected from the group consisting of C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; adding the polystyrene / first solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent under conditions to obtain precipitated polystyrene, and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of 5 ~C 8 adding a volatile organic compound selected from the group consisting of hydrocarbons, and mixtures thereof; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of a hydrocarbon polystyrene non-solvent under conditions to obtain washed polystyrene, and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of the hydrocarbon polystyrene non-solvent under conditions to obtain a double washed polystyrene, and a third portion of the hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the double washed polystyrene; When recycling includes removing the copolymer, the method further comprises: The polystyrene waste is dissolved in a second solvent, the second solvent being C 1 ~C 4a mixture of solvents comprising about 45% to about 95% by weight of the first or second solvent defined above, and about 5% to about 55% by weight of the hydrocarbon polystyrene non-solvent defined above, and dissolving in said mixture a polystyrene / second solvent mixture, and a solid comprising the copolymer; separating a solid comprising the copolymer from the polystyrene / second solvent mixture; adding the polystyrene / second solvent mixture to the first portion of the hydrocarbon polystyrene non-solvent under conditions to obtain precipitated polystyrene, and a first portion of a hydrocarbon waste solution; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of a hydrocarbon polystyrene non-solvent under conditions to obtain washed polystyrene, and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of the hydrocarbon polystyrene non-solvent under conditions to obtain a double washed polystyrene, and a third portion of the hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the dual washed polystyrene.

[0018] In another aspect, the present disclosure provides a method for recycling polystyrene waste, comprising: Reclaiming includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When recycling includes retaining the copolymer, the method further comprises: Dissolving polystyrene waste in benzene or a first solvent to obtain a polystyrene / first solvent mixture, wherein the first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; adding the polystyrene / first solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of 5 ~C 8 and obtaining a mixture thereof selected from the group consisting of hydrocarbons, separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the double washed polystyrene; When recycling includes removing the copolymer, the method further comprises: The polystyrene waste is dissolved in a second solvent, the second solvent being C 1 ~C 4a second solvent selected from benzene substituted with one or two substituents each selected from alkyl, at least one of the one or two substituents being isopropyl, a mixture of solvents comprising about 45% to about 95% by weight of benzene or the first solvent or the second solvent defined above, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent defined above, and dissolving in said mixture to obtain a polystyrene / second solvent mixture, and a solid comprising the copolymer; separating a solid comprising the copolymer from the polystyrene / second solvent mixture; combining the polystyrene / second solvent mixture with a first portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; Precipitated polystyrene, washing with a second portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent; or washing with a mixture of about 45% to about 95% by weight of a hydrocarbon polystyrene non-solvent and about 5% to about 55% by weight of benzene or a second solvent comprising the first solvent or the second solvent defined above, and mixtures thereof to obtain a washed polystyrene and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; The washed polystyrene washing with a third portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent; or washing with a mixture of about 45% to about 95% by weight of a hydrocarbon polystyrene non-solvent and about 5% to about 55% by weight of benzene or the first solvent or the second solvent defined above, and mixtures thereof to obtain a double washed polystyrene and a third portion of the hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; and drying the dual washed polystyrene.

[0019] In another aspect, the present disclosure provides a method for removing brominated polybutadiene polystyrene copolymer from polystyrene waste, comprising: Polystyrene waste, C 1 ~C 4 a second solvent selected from benzene substituted with 1-4, optionally 1 or 2, substituents each selected from alkyl, where at least one of the 1-4 substituents is isopropyl, a mixture of solvents comprising about 45% to about 95% by weight of benzene or the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent, and combining the mixtures to obtain a polystyrene / second solvent mixture and a solid comprising a copolymer, wherein the hydrocarbon polystyrene non-solvent is selected from C 5 ~C 8 and obtaining a hydrocarbon. and separating the copolymer-containing solids from the polystyrene / second solvent mixture; The first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof. [Brief description of the drawings]

[0020] Embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings, in which: [Figure 1] 1 is a graph of the bromine content (ppm) of solutions of polystyrene waste in various benzene-based solvents (p-xylene, p-cymene, toluene, ethylbenzene) at different centrifugation speeds. [Figure 2A] 1 is a graph of the bromine content (ppm) of solutions of polystyrene waste in toluene and in 70 wt % toluene / 30 wt % heptane centrifuged at different centrifugation speeds. [Figure 2B] 1 is a graph of the bromine content (ppm) of solutions of polystyrene waste in toluene and in 70 wt. % ethylbenzene / 30 wt. % heptane centrifuged at different centrifugation speeds. [Figure 2C] 1 is a graph of the bromine content (ppm) of solutions of polystyrene waste in toluene and in 70 wt. % p-cymene / 30 wt. % heptane centrifuged at different centrifugation speeds; [Diagram 3] 1 is a graph of the bromine content (ppm) of a solution of polystyrene waste in p-cymene, p-xylene, toluene, or ethylbenzene before and after filtration using a 1 μm filter, and a solution of polystyrene waste in 70 wt. % p-cymene, p-xylene, toluene, or ethylbenzene and 30 wt. % heptane filtered using a 1 μm filter. [Figure 4] IR spectra of commercial PFR, recovered product C of Example 8, and pure polystyrene.

[0021] Other features and advantages of the present disclosure will become apparent from the following detailed description, however, it should be understood that the detailed description and specific examples illustrating embodiments of the present disclosure are given by way of illustration only, and that the scope of the claims should not be limited by these embodiments, but should be accorded the broadest interpretation consistent with the description as a whole. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] I. Definition Unless otherwise indicated, the definitions and embodiments set forth in this section and other sections are intended to be applicable to all embodiments and aspects of the disclosure described herein where they are appropriate, as understood by one of skill in the art.

[0023] As used herein, the term "and / or" means that the listed items may be present or used either individually or in any combination. In effect, the term means that "at least one of" or "one or more" of the listed items are used or present.

[0024] As used in this disclosure, the singular forms "a," "an," and "the" include plural references unless the content clearly dictates otherwise. For example, an embodiment including "a compound" should be understood to present a particular aspect having one compound or two or more additional compounds.

[0025] In embodiments that include an "additional" or "second" component, such as an additional or second solvent, the second component, as used herein, is chemically distinct from the other component or the first component. A "third" component is distinct from the other component, the first component, and the second component, and further recited or "additional" components are similarly distinct.

[0026] As used in this disclosure and the claims, the terms "comprising" (and any form of including, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "include" and "includes"), or "containing" (and any form of containing, such as "contain" and "contains") are inclusive or open-ended and do not exclude additional, unrecited elements or process steps.

[0027] As used herein, the term "consisting of" and its derivatives are intended to be closed-ended terms specifying the presence of stated features, elements, components, groups, integers, and / or steps and excluding the presence of other, unstated features, elements, components, groups, integers, and / or steps.

[0028] As used herein, the term "consisting essentially of" is intended to specify the presence of stated features, elements, components, groups, integers, and / or steps, and those features, elements, components, groups, integers, and / or steps that do not materially affect the basic and novel characteristics of those features, elements, components, groups, integers, and / or steps.

[0029] This description refers to numerous chemical terms and abbreviations used by those of ordinary skill in the art. Nonetheless, for clarity and consistency, definitions for selected terms are provided.

[0030] As used herein, the terms "about," "substantially," and "approximately" refer to a reasonable amount of deviation from the modified term such that the end result is not significantly altered. These terms of degree should be interpreted to include deviations of at least ±5% of the modified term, unless this deviation negates the meaning of the word it modifies or the context suggests otherwise to one of ordinary skill in the art.

[0031] As used herein, the term "alkyl" whether used alone or as part of another group, means a straight or branched chain saturated alkyl group. The number of carbon atoms possible in the referenced alkyl group is determined by the prefix "C n1~n2 For example, C 1~10 The term alkyl refers to alkyl groups having 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms.

[0032] As used herein, terms such as "polymeric flame retardant" or "PFR" refer to a brominated polybutadiene polystyrene copolymer. For example, the copolymer can be a brominated polybutadiene polystyrene block copolymer of Formula I:

[0033] [ka]

[0034] In some examples, the molecular weight of the copolymer of formula I is about 50 kDa to about 200 kDa, or about 100 kDa. In some embodiments, the copolymer of formula I contains about 35% to about 80% or about 65% bromine by weight. An example of a copolymer of formula I is FR-122P from ICL (CAS1195978-93-8).

[0035] The term "additive" as used herein refers to a chemical added to a polymer to modify at least one physical, biological, and / or chemical property. Non-limiting examples of additives are colorants, fillers, flame retardants, lubricants, and plasticizers.

[0036] The term "hydrocarbon polystyrene non-solvent" as used herein refers to, for example, a hydrocarbon-based compound or mixture thereof in which polystyrene and PFR are substantially insoluble. The selection of an appropriate hydrocarbon polystyrene non-solvent for the process of the present disclosure can be performed by a person skilled in the art. For example, a person skilled in the art will understand that most non-polar additives (e.g., hexabromocyclododecane and silicone oil) and benzene-based solvents commonly found in polystyrene waste are substantially soluble in the hydrocarbon polystyrene non-solvent under the conditions used in the method of the present disclosure to obtain precipitated polystyrene and in the step involving washing with the hydrocarbon polystyrene non-solvent. A person skilled in the art will also understand that it is useful to select a hydrocarbon polystyrene non-solvent that has a boiling point, for example, close to or slightly higher than the glass transition temperature (Tg) of the polystyrene waste being recycled. Alternatively, pressure can be used during the method of the present disclosure, for example, during precipitation and washing, to increase the boiling point of the hydrocarbon polystyrene non-solvent.

[0037] As used herein, "benzene-based solvent" and like terms refer to a solvent in which benzene is substituted one or more times with alkyl substituents, each of which is C 1~4 Alkyl refers to monocyclic aromatic solvents selected from the group consisting of aryl, ... and alkyl.

[0038] As used herein, "carbonaceous additive" and like terms refer to carbon-based materials that are added to polystyrene products.

[0039] II. Methods of the Disclosure In one aspect, the present disclosure provides a method for removing brominated polybutadiene polystyrene copolymer from polystyrene waste, comprising: Polystyrene waste, C 1 ~C 4 a second solvent selected from benzene substituted with 1-4, optionally 1 or 2, substituents each selected from alkyl, where at least one of the 1-4 substituents is isopropyl, a mixture of solvents comprising about 45% to about 95% by weight of the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent, and combining the mixtures to obtain a polystyrene / second solvent mixture and a solid comprising a copolymer, wherein the hydrocarbon polystyrene non-solvent is selected from C 5 ~C 8 and obtaining a hydrocarbon. and separating the copolymer-containing solids from the polystyrene / second solvent mixture; The first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof.

[0040] In another aspect, the present disclosure provides a method for removing brominated polybutadiene polystyrene copolymer from polystyrene waste, comprising: Polystyrene waste, C 1 ~C 4a second solvent selected from benzene substituted with 1-4, optionally 1 or 2, substituents each selected from alkyl, where at least one of the 1-4 substituents is isopropyl, a mixture of solvents comprising about 45% to about 95% by weight of benzene or the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent, and combining the mixtures to obtain a polystyrene / second solvent mixture and a solid comprising a copolymer, wherein the hydrocarbon polystyrene non-solvent is selected from C 5 obtaining a C1-C8 hydrocarbon, and separating the copolymer-containing solids from the polystyrene / second solvent mixture; The first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof.

[0041] In another aspect, the present disclosure provides a method for recycling polystyrene waste, comprising: Reclaiming includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When recycling includes retaining the copolymer, the method further comprises: Dissolving polystyrene waste in a first solvent to obtain a polystyrene / first solvent mixture, the first solvent being selected from the group consisting of C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; adding the polystyrene / first solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of 5 ~C 8 and obtaining a mixture thereof selected from the group consisting of hydrocarbons, separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the double washed polystyrene; When recycling includes removing the copolymer, the method further comprises: The polystyrene waste is dissolved in a second solvent, the second solvent being C 1 ~C 4 a mixture of solvents comprising about 45% to about 95% by weight of the first or second solvent defined above, and about 5% to about 55% by weight of the hydrocarbon polystyrene non-solvent defined above, and dissolving in said mixture a polystyrene / second solvent mixture, and a solid comprising the copolymer; separating a solid comprising the copolymer from the polystyrene / second solvent mixture; combining the polystyrene / second solvent mixture with a first portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; Precipitated polystyrene, washing with a second portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent; or washing with a mixture of about 45% to about 95% by weight of a hydrocarbon polystyrene non-solvent and about 5% to about 55% by weight of the first solvent or the second solvent defined above, and the mixtures to obtain a washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; The washed polystyrene washing with a third portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent; or washing with a mixture of a third solvent comprising about 45% to about 95% by weight of a hydrocarbon polystyrene non-solvent and about 5% to about 55% by weight of the first solvent or the second solvent defined above, and the mixtures thereof to obtain a double washed polystyrene and a third portion of the hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; and drying the dual washed polystyrene.

[0042] In another aspect, the present disclosure provides a method for recovering a carbonaceous additive from polystyrene waste, the method comprising: dissolving the polystyrene waste in a mixture of solvents comprising a second solvent, about 45% to about 95% by weight of the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent, and mixtures thereof to obtain a solid comprising a polystyrene / second solvent mixture and a carbonaceous additive; separating the polystyrene / second solvent mixture and the solids including the carbonaceous additive; washing the solid containing the carbonaceous additive with a first solvent to obtain a carbonaceous additive and a first solvent solution; and optionally drying the carbonaceous additive; The first solvent is C 1 and C 2benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; The second solvent is C 1 ~C 4 benzene substituted with one or two substituents each selected from alkyl, wherein at least one of the one or two substituents is isopropyl; Hydrocarbon polystyrene non-solvent, C 5 ~C 8 The process includes a method in which the hydrocarbon is selected from the group consisting of benzene, toluene ...

[0043] In another aspect, the present disclosure provides a method for recycling polystyrene waste, comprising: Reclaiming includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When recycling includes retaining the copolymer, the method further comprises: Dissolving polystyrene waste in a first solvent to obtain a polystyrene / first solvent mixture, the first solvent being selected from the group consisting of C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; adding the polystyrene / first solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of 5 ~C 8 and obtaining a mixture thereof selected from the group consisting of hydrocarbons, separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the double washed polystyrene; When recycling includes removing the copolymer, the method further comprises: The polystyrene waste is dissolved in a second solvent, the second solvent being C 1 ~C 4 a mixture of solvents comprising about 45% to about 95% by weight of the first or second solvent defined above, and about 5% to about 55% by weight of the hydrocarbon polystyrene non-solvent defined above, and dissolving in said mixture a polystyrene / second solvent mixture, and a solid comprising the copolymer; separating a solid comprising the copolymer from the polystyrene / second solvent mixture; adding the polystyrene / second solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the dual washed polystyrene.

[0044] In another aspect, the present disclosure provides the use of a second solvent in the removal of a brominated polybutadiene polystyrene copolymer, comprising: The second solvent is C 1 ~C 4 benzene substituted with one or two substituents each selected from alkyl, at least one of the one or two substituents being isopropyl; the mixture of solvents comprising from about 45% to about 95% by weight of the first solvent or the second solvent, and from about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent; and mixtures thereof; The first solvent is selected from benzene substituted with one or two substituents each selected from C1 and C2 alkyl, and mixtures thereof.

[0045] In another aspect, the present disclosure provides the use of a second solvent in the recovery of a brominated polybutadiene polystyrene copolymer, comprising: the second solvent is selected from benzene substituted with one or two substituents each selected from C1-C4 alkyl, at least one of the one or two substituents being isopropyl; the mixture of solvents comprises about 45% to about 95% by weight of the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent; and mixtures thereof; The first solvent is selected from benzene substituted with one or two substituents each selected from C1 and C2 alkyl, and mixtures thereof.

[0046] In another aspect, the present disclosure includes the use of the brominated polybutadiene polystyrene copolymer recovered from the process of the present disclosure in the production of a polystyrene product, optionally wherein the polystyrene product is a thermal insulation material.

[0047] In another aspect, the present disclosure includes the use of a carbonaceous additive recovered from polystyrene waste by the method of the present disclosure in the production of a polystyrene product, optionally wherein the product is a thermal insulation material.

[0048] It may be understood that the recovered brominated polybutadiene polystyrene copolymers and recovered carbonaceous additives of the present disclosure may contain small amounts of residual polystyrene. Because the polystyrene product already contains polystyrene, the small amount of residual polystyrene does not affect the use of the recovered brominated polybutadiene polystyrene copolymers or recovered carbonaceous additives in the production of the polystyrene product.

[0049] In another aspect, the present disclosure provides a method for recycling polystyrene waste, comprising: Reclaiming includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When recycling includes retaining the copolymer, the method further comprises: Dissolving polystyrene waste in a first solvent to obtain a polystyrene / first solvent mixture, the first solvent being selected from the group consisting of C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; adding the polystyrene / first solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent under conditions to obtain precipitated polystyrene, and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of 5 ~C 8 adding a volatile organic compound selected from the group consisting of hydrocarbons, and mixtures thereof; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of a hydrocarbon polystyrene non-solvent under conditions to obtain washed polystyrene, and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of the hydrocarbon polystyrene non-solvent under conditions to obtain a double washed polystyrene, and a third portion of the hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the double washed polystyrene; When recycling includes removing the copolymer, the method further comprises: The polystyrene waste is dissolved in a second solvent, the second solvent being C 1 ~C 4 a mixture of solvents comprising about 45% to about 95% by weight of the first or second solvent defined above, and about 5% to about 55% by weight of the hydrocarbon polystyrene non-solvent defined above, and dissolving in said mixture a polystyrene / second solvent mixture, and a solid comprising the copolymer; separating a solid comprising the copolymer from the polystyrene / second solvent mixture; adding the polystyrene / second solvent mixture to the first portion of the hydrocarbon polystyrene non-solvent under conditions to obtain precipitated polystyrene, and a first portion of a hydrocarbon waste solution; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of a hydrocarbon polystyrene non-solvent under conditions to obtain washed polystyrene, and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of the hydrocarbon polystyrene non-solvent under conditions to obtain a double washed polystyrene, and a third portion of the hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the dual washed polystyrene.

[0050] In another aspect, the present disclosure provides a method for recycling polystyrene waste, comprising: Reclaiming includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When recycling includes retaining the copolymer, the method further comprises: Dissolving polystyrene waste in benzene or a first solvent to obtain a polystyrene / first solvent mixture, wherein the first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; adding the polystyrene / first solvent mixture to a first portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of 5 ~C 8 and obtaining a mixture thereof selected from the group consisting of hydrocarbons, separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; washing the precipitated polystyrene with a second portion of the hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; Optionally, drying the double washed polystyrene; When recycling includes removing the copolymer, the method further comprises: The polystyrene waste is dissolved in a second solvent, the second solvent being C 1 ~C 4 a second solvent selected from benzene substituted with one or two substituents each selected from alkyl, at least one of the one or two substituents being isopropyl, a mixture of solvents comprising about 45% to about 95% by weight of benzene or the first solvent or the second solvent defined above, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent defined above, and dissolving in said mixture to obtain a polystyrene / second solvent mixture, and a solid comprising the copolymer; separating a solid comprising the copolymer from the polystyrene / second solvent mixture; combining the polystyrene / second solvent mixture with a first portion of a hydrocarbon polystyrene non-solvent at a boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating steps; Precipitated polystyrene, washing with a second portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent; or washing with a mixture of about 45% to about 95% by weight of a hydrocarbon polystyrene non-solvent and about 5% to about 55% by weight of benzene or a second solvent comprising the first solvent or the second solvent defined above, and mixtures thereof to obtain a washed polystyrene and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from the second portion of the hydrocarbon waste solution; The washed polystyrene washing with a third portion of the hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent; or washing with a mixture of about 45% to about 95% by weight of a hydrocarbon polystyrene non-solvent and about 5% to about 55% by weight of benzene or the first solvent or the second solvent defined above, and mixtures thereof to obtain a double washed polystyrene and a third portion of the hydrocarbon waste solution; separating the dual washed polystyrene from a third portion of the hydrocarbon waste solution; and drying the dual washed polystyrene.

[0051] In another aspect, the present disclosure provides a method for removing brominated polybutadiene polystyrene copolymer from polystyrene waste, comprising: Polystyrene waste, C 1 ~C 4 a second solvent selected from benzene substituted with 1-4, optionally 1 or 2, substituents each selected from alkyl, where at least one of the 1-4 substituents is isopropyl, a mixture of solvents comprising about 45% to about 95% by weight of benzene or the first solvent or the second solvent, and about 5% to about 55% by weight of a hydrocarbon polystyrene non-solvent, and combining the mixtures to obtain a polystyrene / second solvent mixture and a solid comprising a copolymer, wherein the hydrocarbon polystyrene non-solvent is selected from C 5 ~C 8 and obtaining a hydrocarbon. and separating the copolymer-containing solids from the polystyrene / second solvent mixture; The first solvent is C 1 and C 2 benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof.

[0052] In some embodiments, the polystyrene waste further comprises a carbonaceous additive and the solids comprising the copolymer further comprise a carbonaceous additive.

[0053] In some embodiments, the carbonaceous additive is one or more of graphite, graphene, carbon black, coke, char, tar, biochar, products of pyrolysis processes, and modified products.

[0054] In some embodiments, the disclosed method of removing brominated polybutadiene polystyrene copolymer from polystyrene waste further comprises recovering the carbonaceous additive from the copolymer-containing solids by dispersing the copolymer-containing solids in a first solvent as defined herein to obtain a first solvent / copolymer solution comprising the copolymer, and a solid residue comprising the carbonaceous additive.

[0055] In some embodiments, washing of the precipitated polystyrene is with a continuous flow of a second portion of the hydrocarbon polystyrene non-solvent or mixture of second solvents.

[0056] In some embodiments, washing of the washed polystyrene is with a continuous flow of a third portion of a hydrocarbon polystyrene non-solvent or mixture of third solvents.

[0057] In some embodiments, the removal of the brominated polybutadiene polystyrene copolymer is selective, for example, the removal of the brominated polybutadiene polystyrene copolymer is more selective than the removal of other brominated flame retardants, such as HBCD.

[0058] In some embodiments, the conditions include carrying out the washes and / or additions at the boiling point of the hydrocarbon polystyrene non-solvent.

[0059] In some embodiments, separation of the solids comprising the copolymer is carried out by filtration, centrifugation, decantation, settling, or a combination thereof.

[0060] In some embodiments, filtration is performed using a filter of about 0.25 μm to about 1000 μm, about 0.25 μm to about 800 μm, about 0.25 μm to about 600 μm, about 0.25 μm to about 400 μm, about 0.25 μm to about 200 μm, about 0.25 μm to about 100 μm, about 0.25 μm to about 50 μm, about 0.25 μm to about 30 μm, about 0.25 μm to about 20 μm, about 0.25 μm to about 10 μm, about 0.25 μm to about 5 μm, about 0.25 to about 3 μm, about 0.5 μm to about 2 μm, about 0.5 μm to about 1.5 μm, or about 1 μm.

[0061] In some embodiments, centrifugation is carried out at about 1500 rpm or greater, about 1500 rpm to about 10000 rpm, about 2000 rpm to about 9500 rpm, about 3000 rpm to about 9500 rpm, In some embodiments, centrifugation is carried out at about 4000 rpm to about 9500 rpm, or about 4000 rpm or greater.

[0062] In some embodiments, centrifugation is carried out at about 600 RCF to about 10,000 RCF, about 600 RCF to about 9,000 RCF, about 700 RCF to about 8,900 RCF, about 1,000 RCF to about 7,000 RCF, about 1,000 RCF to about 5,000 RCF, about 1,000 RCF to about 3,000 RCF, or about 1,500 RCF to about 2,700 RCF.

[0063] In some embodiments, centrifugation is carried out for about 5 seconds to about 20 minutes, about 3 minutes to about 10 minutes, about 5 seconds to about 5 minutes, about 10 seconds to about 10 minutes, about 10 seconds to about 5 minutes, about 5 minutes to about 15 minutes, or about 10 seconds to about 2 minutes.

[0064] In some embodiments, the first solvent is selected from toluene, ethylbenzene, p-xylene, p-ethyltoluene, and mixtures thereof, In some embodiments, the first solvent is toluene, ethylbenzene, or mixtures thereof.

[0065] In some embodiments, benzene may be used in place of the first solvent.

[0066] In some embodiments, the hydrocarbon polystyrene non-solvent is selected from C6 to C8 alkanes, and mixtures thereof.

[0067] In some embodiments, the hydrocarbon polystyrene non-solvent is selected from C6 to C7 alkanes, and mixtures thereof.

[0068] In some embodiments, the hydrocarbon polystyrene non-solvent is n-pentane, pentanes, hexanes, n-hexane, heptanes, or n-heptane.

[0069] In some embodiments, the second solvent is selected from cumene, p-cymene, mixtures of solvents, and mixtures thereof.

[0070] In some embodiments, the solvent mixture comprises about 50% to about 90% by weight of the first solvent, and about 10% to about 50% by weight of the hydrocarbon polystyrene non-solvent.

[0071] In some embodiments, the mixture of solvents comprises about 60% to about 80% by weight of the first solvent, and about 20% to about 40% by weight of the hydrocarbon polystyrene non-solvent.

[0072] In some embodiments, the solvent mixture comprises about 65% to about 75% by weight of the first solvent, and about 25% to about 35% by weight of the hydrocarbon polystyrene non-solvent.

[0073] In some embodiments, the mixture of solvents comprises about 70% by weight of the first solvent and about 30% by weight of the hydrocarbon polystyrene non-solvent.

[0074] In some embodiments, the second solvent is p-cymene.

[0075] In some embodiments, the second solvent is about 70% by weight toluene / about 30% by weight n-heptane, about 70% by weight ethylbenzene / about 30% by weight n-heptane, about 70% by weight toluene / about 30% by weight n-hexane.

[0076] In some embodiments, the dissolving, adding, and washing are each performed with stirring, optionally by a mechanical stirrer.

[0077] In some embodiments, the methods of the present disclosure further include recovering the stripped copolymer.

[0078] In some embodiments, the brominated polybutadiene polystyrene copolymer is a brominated polybutadiene polystyrene block copolymer.

[0079] In some embodiments, the block copolymer is of formula I:

[0080] [ka]

[0081] In some embodiments, the block copolymer comprises from about 35% to about 80% bromine by weight.

[0082] In some embodiments, the polystyrene / first solvent mixture comprises about 5% to about 30% by weight, about 10% to about 25% by weight, or about 20% by weight of waste polystyrene.

[0083] In some embodiments, the polystyrene / second solvent mixture comprises about 5% to about 30% by weight, about 10% to about 25% by weight, or about 20% by weight of waste polystyrene.

[0084] In some embodiments, the brominated polybutadiene polystyrene copolymer is a brominated polybutadiene polystyrene block copolymer. In some embodiments, the brominated polybutadiene polystyrene block copolymer is a copolymer of Formula I:

[0085] In some embodiments, where recycling includes removal of the copolymer of formula I, the recycled polystyrene contains about or less than 300 ppm, about or less than 200 ppm, about or less than 150 ppm, about or less than 135 ppm, about or less than 100 ppm, about or less than 85 ppm, about or less than 75 ppm, about or less than 65 ppm, about or less than 55 ppm, about or less than 45 ppm, about or less than 40 ppm, about or less than 20 ppm, or about or less than 10 ppm of bromine, wherein the bromine is contained in the copolymer of formula I. In some embodiments, where recycling includes removal of the copolymer of Formula I, the recycled polystyrene contains from about 10 ppm to about 300 ppm, from about 30 ppm to about 200 ppm, from about 30 ppm to about 150 ppm, from about 30 ppm to about 135 ppm, from about 30 ppm to about 100 ppm, from about 30 ppm to about 70 ppm, from about 30 ppm to about 50 ppm, or from about 30 ppm to about 40 ppm of bromine, wherein the bromine is contained in the copolymer of Formula I. EXAMPLES

[0086] The following non-limiting examples are illustrative of the present disclosure.

[0087] General method The polystyrene used is a post-industrial EPS material containing approximately 6400 ppm PFR in bromine. Pure hexabromocyclododecane (HBCD) was used to spike the polystyrene into a model mixture of polystyrene streams with both HBCD and PFR. HBCD and all solvents were analytical grade and purchased from Sigma-Aldrich.

[0088] Example 1 General Method of the Disclosure Typically, polystyrene waste (e.g., post-industrial EPS material) was dissolved at 20 wt.% in a first solvent or a second solvent. The resulting mixture was filtered at 1 μm or centrifuged at different RPM. The filtrate containing the polystyrene was added to a stirred solution of a hydrocarbon non-solvent at its boiling point to precipitate the polystyrene. The precipitated polystyrene was washed twice with an additional amount of the hydrocarbon polystyrene non-solvent at the boiling point of the non-solvent. The washed polystyrene was optionally dried in a vacuum oven at about 130° C. for about 4 hours.

[0089] Example 2 Solubility of PFR in benzene-based solvents An experimental design was established by using solvents that increase steric hindrance. Monosubstituted benzene-based solvents and their para-disubstituted congeners were compared, as seen in Table 1. The effect of the solvent structure on the solubility of the block copolymer of formula I in solution was investigated. All of these solvents have been shown to be effective in solubilizing polystyrene, but not the same as in the case of PFR. Some of them showed poor or no solubility, while others showed iridescent solutions, an indication of the potential lyotropic properties of PFR.

[0090] [Table 1]

[0091] Example 3 Removal of HBCD Table 2 shows that HBCD can be removed from polystyrene waste material by using p-cymene and heptane as a solvent / hydrocarbon polystyrene non-solvent combination, where, as an example, it is shown that the HBCD concentration can be reduced to 0.53 ppm after three dissolution / precipitation cycles.

[0092] [Table 2]

[0093] Example 4 Removal of PFRs by centrifugation using different solvents Different monocyclic aromatic solvents (p-cymene, p-xylene, toluene, and ethylbenzene) were used to solubilize polystyrene waste. When p-cymene was used as the solvent, insoluble particles were observed. The solutions were centrifuged at different RPMs (0 RPM, 2500 RPM (727 RCF), 4500 RPM (2354 RCF), 6500 RPM (4912 RCF), and 8500 RPM (8399 RCF) and the bromine content was evaluated by X-ray fluorescence spectroscopy. The results are shown in Figure 1.

[0094] Figure 1 shows that depending on the benzene-based solvent, the solubility of the PFR can be adjusted. If a lower solubility is observed, such as p-cymene, the PFR can be removed as a solid, such as by centrifugation. Due to the gradient of particle sizes of the insoluble PFR and its polydispersity, it is possible to control the concentration of the PFR in the final recycled material.

[0095] Example 5 Effect of adding a hydrocarbon non-solvent to a monocyclic aromatic benzene solvent Since PFRs are insoluble in hydrocarbon polystyrene non-solvents, hydrocarbon polystyrene non-solvents were added to benzene-based solvents including toluene, ethylbenzene, and p-xylene to reduce the solubility of PFRs. 30 wt% of a hydrocarbon polystyrene non-solvent, such as heptane, was added to toluene, p-xylene, and ethylbenzene. The resulting mixture of solvents was used to solubilize the polystyrene waste. A 20 wt% solution of polystyrene waste was prepared using the mixture of solvents. The polystyrene solution was centrifuged at different speeds (0 RPM, 2500 RPM (727 RCF), 4500 RPM (2354 RCF), 6500 RPM (4912 RCF), and 8500 RPM (8399 RCF)) and the bromine content of the supernatant was evaluated by X-ray fluorescence spectroscopy. The results are shown in Figure 2.

[0096] Figure 2 shows that the addition of a hydrocarbon polystyrene non-solvent in a benzene-based solvent, which was less effective at precipitating the PFR, was able to reduce the solubility of the PFR in the benzene-based solvent, but did not significantly change the solubility of the PFR in solvents such as p-cymene (which had low solubility for the PFR). The insoluble PFR was removed from the polystyrene solution by centrifugation.

[0097] Example 6 Removal of PFR by filtration Polystyrene waste was dissolved at 20 wt% in a benzene-based solvent containing p-cymene, p-xylene, toluene, and ethylbenzene, or in a mixture of 70 wt% benzene-based solvent and 30 wt% hydrocarbon polystyrene non-solvent. The resulting mixture was filtered through a 1 μm filter. The bromine content of the starting and filtered mixtures in each case was evaluated by X-ray fluorescence spectroscopy. The results are shown in Figure 3.

[0098] For p-cymene, which has low solubility for PFRs, it was possible to remove virtually all of the PFRs from the polystyrene waste solution by filtration. In the cases of p-xylene, toluene, and ethylbenzene, which were unable to precipitate the PFRs, the addition of a hydrocarbon polystyrene non-solvent reduced the solubility of the PFRs in the respective solvents. As shown in Figure 3, it was possible to remove the PFRs from a solution of polystyrene waste in a mixture of solvents including a hydrocarbon polystyrene non-solvent and a benzene-based solvent by filtration.

[0099] Example 7 Removal of HBCD and removal and retention of PFR Table 3 shows that HBCD was removed while retaining the PFRs in the recycled polystyrene. Different solvents and mixtures of solvents (with hydrocarbon polystyrene non-solvents) were used and evaluated. Toluene and p-xylene alone allowed the PFRs to be retained in the recycled polystyrene, while HBCD was still removed. Solvent mixtures of toluene, p-xylene, or ethyltoluene with hexane or heptane were able to remove both HBCD and PFRs. In the case of p-cymene, p-cymene alone was able to remove both HBCD and PFRs.

[0100] [Table 3]

[0101] Example 7 Selective removal of HBCD and PFR Two feedstocks, post-consumer polystyrene, were used to test for selective removal of HBCD and PFRs. Feedstock A: Contains HBCD · Feedstock B: Contains HBCD+PFR

[0102] Using the method of the present disclosure, HBCD was removed in both feedstocks and the PFR in Feedstock B was retained.

[0103] Both feedstocks were processed at pilot scale in 25 kg batches following the same procedure. The feedstock was dissolved in a mixture of p-cymene and heptane (70:30 wt%). After passing the resulting mixture through a 100 μm filter, polystyrene was precipitated from the solution by adding heptane at its boiling point in continuous mode until a solvent composition of 70 wt% heptane and 30 wt% p-cymene was reached. The precipitated polystyrene paste was then washed continuously with a mixture of 70 wt% heptane and 30 wt% p-cymene at the boiling point of heptane for about 1 hour to about 3 hours. The resulting paste was washed with pure heptane in continuous mode for about 0.5 hours and further extruded to produce recycled polystyrene pellets. Bromine content was evaluated by X-ray fluorescence (XRF) and UPLC-MS / MS.

[0104] [Table 4]

[0105] [Table 5]

[0106] For Feedstock A, the pilot scale process succeeded in removing 98.6% of HBCD with a final value of 69.3 ppm, which is below the 100 ppm threshold required by European legislation for polystyrene materials. HBCD can be extracted from the polystyrene material by acetone. This was done for the starting material and the recycled pellets. The acetone extract was analyzed by XRF to verify the UPLC-MS / MS results. The results are shown in Table 4. The UPLC-MS / MS and XRF results were similar.

[0107] For Feedstock B, the starting material contained approximately 5373 ppm of soluble brominated compounds (i.e., HBCD). Since PRF is not soluble in acetone and cannot be extracted, the difference between the total bromine content and the soluble bromine can be related to insoluble brominated compounds (i.e., PFR). Thus, the bromine associated with PFR is 3611 ppm in the starting material. In the recycled pellets from Feedstock B, 98.8% of the HBCD was removed and 70% of the PFR was retained.

[0108] Example 8 Recovery of PFR from black polystyrene feedstock The recovery of PFR was evaluated using a black polystyrene feedstock. 40 g of black polystyrene feedstock was dissolved in a mixture of 160 g p-cymene and 48 g heptane (77 wt. % p-cymene: 23 wt. % heptane) at 60° C. with stirring. Once all the feedstock was dissolved, the solution was centrifuged at 8500 rpm for 10 minutes. The supernatant solution containing polystyrene was collected. The polystyrene was then precipitated by adding the supernatant solution into 272 g heptane at the boiling point of heptane with vigorous stirring. The resulting PS paste was then washed twice with 272 g heptane at its boiling point. The washed PS paste was dried in a vacuum oven at 140° C. for 4 hours. Approximately 80 wt. % of the initial feedstock was recovered from the feedstock (Product A).

[0109] 1 g of the centrifugation insoluble residue was dispersed in 20 g of toluene. The resulting mixture was heated to 80° C. under vigorous stirring. The solution was then centrifuged at 8500 rpm for 10 min. The centrifugation residue was washed twice with 10 g of fresh toluene, then centrifuged again at 8500 rpm for 10 min, and then dried under vacuum at 140° C. for 4 h. The recovered residue was a carbonaceous material representing about 14 wt. % from the feed (Product B). The toluene soluble fraction from the supernatant solution was evaporated. The recovered evaporation residue was determined to be PFR and represented about 1 wt. % of the feed (Product C). The same products could be extracted with benzene or other substituted benzene solvents. Products A, B, and C were analyzed by XRF. The results are shown in Table 9.

[0110] [Table 6]

[0111] The recovered carbonaceous material, Product B, contained common additives in polystyrene products, such as one or more of graphite, graphene, carbon black, coke, char, tar, biochar, products of pyrolysis processes, and modified products. The carbonaceous material may further include carbonates, such as calcium carbonate.

[0112] Infrared (IR) was used to evaluate Product C and compare it to commercial PFR and pure polystyrene. (Figure 4) Product C showed bands corresponding to C-Br bonds seen in PFR but not in polystyrene. Product C was also shown to contain polystyrene. It should be noted that residual polystyrene in Product C can be removed by washing Product C with a second solvent, such as p-cymene, which selectively dissolves polystyrene over PFR. Nevertheless, Product C can also be used directly as a PFR flame retardant additive for polystyrene products, since the residual polystyrene will not interfere with the polystyrene already present in the polystyrene product.

[0113] Although the present disclosure has been described with reference to examples, it should be understood that the claims should not be limited by the embodiments described in the examples, but should be given the broadest interpretation consistent with the description as a whole.All publications, patents and patent applications are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.When a term in this disclosure is found to be defined differently in a document incorporated herein by reference, the definition provided herein serves as the definition of that term.

Claims

1. 1. A method for removing brominated polybutadiene polystyrene copolymer from polystyrene waste, comprising: combining the polystyrene waste with a solvent mixture comprising about 50% to about 90% by weight of a first solvent or a second solvent and about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent to obtain a polystyrene / second solvent mixture and a solid comprising the copolymer, wherein the hydrocarbon polystyrene non-solvent is selected from the group consisting of C ５ ~C ８ obtaining a hydrocarbon; separating the solids containing the copolymer from the polystyrene / second solvent mixture; The first solvent is C １ and C ２ benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; The second solvent is C １ ~C ４ benzene substituted with 1 to 4, optionally 1 or 2, substituents each selected from alkyl, wherein at least one of said 1 to 4 substituents is isopropyl.

2. 10. The method of claim 1, wherein the polystyrene waste further comprises a carbonaceous additive, and wherein the solids comprising the copolymer further comprise the carbonaceous additive, and optionally, the carbonaceous additive is one or more of graphite, graphene, carbon black, coke, char, tar, biochar, a product of a pyrolysis process, and a modification product.

3. 3. The method of claim 2, wherein the method further comprises recovering the carbonaceous additive from the solids comprising the copolymer by dispersing the solids comprising the copolymer in a first solvent as defined in claim 1 to obtain a first solvent / copolymer solution comprising the copolymer and a solid residue comprising the carbonaceous additive.

4. A method for recycling polystyrene waste, comprising: The method comprises: dissolving the polystyrene waste in a mixture of solvents comprising about 50% to about 90% by weight of a first solvent or a second solvent and about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent to obtain a polystyrene / second solvent mixture and a solid comprising the copolymer; The first solvent is C １ and C ２ benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; The second solvent is C １ ~C ４ benzene substituted with 1 to 4, optionally 1 or 2, substituents each selected from alkyl, wherein at least one of the 1 to 4 substituents is isopropyl; The hydrocarbon polystyrene non-solvent is C ５ ~C ８ obtaining a hydrocarbon; separating the solids comprising the copolymer from the polystyrene / second solvent mixture; combining the polystyrene / second solvent mixture with a first portion of a hydrocarbon-polystyrene non-solvent at the boiling point of the hydrocarbon-polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating the precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating; The precipitated polystyrene washing with a second portion of a hydrocarbon polystyrene non-solvent at the boiling point of said hydrocarbon polystyrene non-solvent; washing with a mixture of about 50% to about 90% by weight of the hydrocarbon polystyrene non-solvent and about 10% to about 50% by weight of the first solvent or the second solvent defined above, and the mixtures thereof, to obtain washed polystyrene and a second portion of the hydrocarbon waste solution; separating the washed polystyrene from a second portion of the hydrocarbon waste solution; The washed polystyrene washing with a third portion of a hydrocarbon polystyrene non-solvent at the boiling point of said hydrocarbon polystyrene non-solvent; or washing with a mixture of a third solvent comprising about 50% to about 90% by weight of the hydrocarbon polystyrene non-solvent and about 10% to about 50% by weight of the first solvent or the second solvent defined above, and mixtures thereof, to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the double washed polystyrene from a third portion of the hydrocarbon waste solution; and drying the double-washed polystyrene.

5. A method for recycling polystyrene waste, comprising: the recycling includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When the recycling includes retaining the copolymer, the method further comprises: Dissolving the polystyrene waste in a first solvent to obtain a polystyrene / first solvent mixture, wherein the first solvent is selected from the group consisting of C １ and C ２ and obtaining a benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof. adding the polystyrene / first solvent mixture to a first portion of a hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of ５ ~C ８ and obtaining a soluble solid, selected from the group consisting of hydrocarbons, and mixtures thereof. separating the precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating; washing the precipitated polystyrene with a second portion of a hydrocarbon-polystyrene non-solvent at the boiling point of the hydrocarbon-polystyrene non-solvent to obtain washed polystyrene and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from a second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent to obtain a double-washed polystyrene and a third portion of a hydrocarbon waste solution; separating the double washed polystyrene from a third portion of the hydrocarbon waste solution; optionally drying the double-washed polystyrene; When the recycling includes removing the copolymer, the method further comprises: dissolving the polystyrene waste in a mixture of solvents comprising about 50% to about 90% by weight of a first solvent or a second solvent as defined above, and about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent as defined above, to obtain a polystyrene / second solvent mixture and a solid comprising the copolymer; The second solvent is C １ ~C ４ benzene substituted with 1 to 4, optionally 1 or 2, substituents each selected from alkyl, wherein at least one of the 1 to 4 substituents is isopropyl; separating the solids comprising the copolymer from the polystyrene / second solvent mixture; adding the polystyrene / second solvent mixture to a first portion of a hydrocarbon-polystyrene non-solvent at the boiling point of the hydrocarbon-polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating the precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating; washing the precipitated polystyrene with a second portion of a hydrocarbon-polystyrene non-solvent at the boiling point of the hydrocarbon-polystyrene non-solvent to obtain washed polystyrene and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from a second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent to obtain a double-washed polystyrene and a third portion of a hydrocarbon waste solution; separating the double washed polystyrene from a third portion of the hydrocarbon waste solution; optionally drying the double-washed polystyrene.

6. 6. The method of claim 4 or 5, wherein when the recycling includes removing the copolymer, the solids including the copolymer further include a carbonaceous additive, optionally the carbonaceous additive being one or more of graphite, graphene, carbon black, coke, char, tar, biochar, products of pyrolysis processes, and modification products.

7. 7. The method of claim 6, wherein the method further comprises recovering the carbonaceous additive from the solids comprising the copolymer by dispersing the solids comprising the copolymer in a first solvent as defined in claim 2 to obtain a first solvent / copolymer solution comprising the copolymer and a solid residue comprising the carbonaceous additive.

8. 6. The method of claim 4 or 5, wherein the washing of the precipitated polystyrene is with a continuous flow of the second portion of the hydrocarbon polystyrene non-solvent or the mixture of the second solvents.

9. 6. The method of claim 4, wherein the washing of the washed polystyrene is with a continuous flow of a third portion of the hydrocarbon polystyrene non-solvent or a mixture of the third solvents.

10. 6. The method of claim 4 or 5, wherein the separation of the solids comprising the copolymer is carried out by filtration, centrifugation, decantation, sedimentation, or a combination thereof.

11. 6. The method of claim 4 or 5, wherein the dissolving, adding, and washing are each performed with stirring, optionally by a mechanical stirrer.

12. 6. The method of claim 4 or 5, further comprising recovering the stripped copolymer.

13. 1. A method for recovering a carbonaceous additive from polystyrene waste, comprising: dissolving the polystyrene waste in a mixture of solvents comprising about 50% to about 90% by weight of a first solvent or a second solvent and about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent to obtain a solid comprising a polystyrene / second solvent mixture and the carbonaceous additive; separating the polystyrene / second solvent mixture from the solids containing the carbonaceous additive; washing the solid containing the carbonaceous additive with a first solvent to obtain the carbonaceous additive and a first solvent solution; and optionally drying the carbonaceous additive; The first solvent is C １ and C ２ benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; The second solvent is C １ ~C ４ benzene substituted with one or two substituents each selected from alkyl, wherein at least one of the one or two substituents is isopropyl; The hydrocarbon polystyrene non-solvent is C ５ ~C ８ hydrocarbons, and mixtures thereof.

14. 14. The method of claim 13, wherein the polystyrene waste comprises a brominated polybutadiene polystyrene copolymer, the method further comprising recovering the brominated polybutadiene polystyrene copolymer, and the first solvent solution comprises the brominated polybutadiene polystyrene copolymer.

15. 1. Use of a mixture of solvents in the removal of a brominated polybutadiene polystyrene copolymer, the mixture of solvents comprising from about 50% to about 90% by weight of a first solvent or a second solvent, and from about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent; The first solvent is C １ and C ２ benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; The second solvent is C １ ~C ４ benzene substituted with one or two substituents each selected from alkyl, wherein at least one of said one or two substituents is isopropyl.

16. 1. Use of a mixture of solvents in the recovery of a brominated polybutadiene polystyrene copolymer, said mixture of solvents comprising from about 50% to about 90% by weight of a first solvent or a second solvent, and from about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent, and mixtures thereof; The first solvent is C １ and C ２ benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; The second solvent is C １ ~C ４ benzene substituted with one or two substituents each selected from alkyl, wherein at least one of said one or two substituents is isopropyl.

17. 13. Use of the brominated polybutadiene polystyrene copolymer recovered from the process of claim 12 in the manufacture of a polystyrene product, optionally wherein the polystyrene product is a thermal insulation material.

18. 15. Use of a carbonaceous additive recovered from polystyrene waste by the method of claim 13 or 14 in the manufacture of a polystyrene product, optionally wherein the product is a thermal insulation material.

19. A method for recycling polystyrene waste, comprising: the recycling includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When the recycling includes retaining the copolymer, the method further comprises: Dissolving the polystyrene waste in a first solvent to obtain a polystyrene / first solvent mixture, wherein the first solvent is selected from the group consisting of C １ and C ２ and obtaining a benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof. adding the polystyrene / first solvent mixture to a first portion of a hydrocarbon polystyrene non-solvent under conditions to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of ５ ~C ８ adding a hydroxybenzoate selected from the group consisting of hydrocarbons, and mixtures thereof; separating the precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating; washing the precipitated polystyrene with a second portion of a hydrocarbon polystyrene non-solvent under conditions to obtain washed polystyrene and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from a second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent under conditions to obtain double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the double washed polystyrene from a third portion of the hydrocarbon waste solution; optionally drying the double-washed polystyrene; When the recycling includes removing the copolymer, the method further comprises: dissolving the polystyrene waste in a mixture of solvents comprising about 50% to about 90% by weight of a first solvent or a second solvent as defined above, and about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent as defined above, to obtain a polystyrene / second solvent mixture and a solid comprising the copolymer; The second solvent is C １ ~C ４ benzene substituted with one or two substituents each selected from alkyl, wherein at least one of the one or two substituents is isopropyl; separating the solids comprising the copolymer from the polystyrene / second solvent mixture; adding the polystyrene / second solvent mixture to a first portion of a hydrocarbon-polystyrene non-solvent under conditions to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating the precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating; washing the precipitated polystyrene with a second portion of a hydrocarbon polystyrene non-solvent under conditions to obtain washed polystyrene and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from a second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent under conditions to obtain double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the double washed polystyrene from a third portion of the hydrocarbon waste solution; optionally drying the double-washed polystyrene.

20. A method for recycling polystyrene waste, comprising: the recycling includes retaining the brominated polybutadiene polystyrene copolymer or removing the copolymer; When the recycling includes retaining the copolymer, the method further comprises: Dissolving the polystyrene waste in benzene or a first solvent to obtain a polystyrene / first solvent mixture, wherein the first solvent is selected from the group consisting of C １ and C ２ and obtaining a benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof. adding the polystyrene / first solvent mixture to a first portion of a hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution, wherein the hydrocarbon polystyrene non-solvent is a mixture of ５ ~C ８ and obtaining a soluble solid, selected from the group consisting of hydrocarbons, and mixtures thereof. separating the precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating; washing the precipitated polystyrene with a second portion of a hydrocarbon-polystyrene non-solvent at the boiling point of the hydrocarbon-polystyrene non-solvent to obtain washed polystyrene and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from a second portion of the hydrocarbon waste solution; washing the washed polystyrene with a third portion of a hydrocarbon polystyrene non-solvent at the boiling point of the hydrocarbon polystyrene non-solvent to obtain a double-washed polystyrene and a third portion of a hydrocarbon waste solution; separating the double washed polystyrene from a third portion of the hydrocarbon waste solution; optionally drying the double-washed polystyrene; When the recycling includes removing the copolymer, the method further comprises: dissolving the polystyrene waste in a mixture of solvents comprising about 50% to about 90% by weight of benzene or a first solvent or a second solvent as defined above, and about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent as defined above, to obtain a polystyrene / second solvent mixture and a solid comprising the copolymer; The second solvent is C １ ~C ４ benzene substituted with one or two substituents each selected from alkyl, wherein at least one of the one or two substituents is isopropyl; separating the solids comprising the copolymer from the polystyrene / second solvent mixture; combining the polystyrene / second solvent mixture with a first portion of a hydrocarbon-polystyrene non-solvent at the boiling point of the hydrocarbon-polystyrene non-solvent to obtain precipitated polystyrene and a first portion of a hydrocarbon waste solution; separating the precipitated polystyrene from a first portion of the hydrocarbon waste solution, optionally repeating the dissolving, adding, and separating; The precipitated polystyrene washing with a second portion of a hydrocarbon polystyrene non-solvent at the boiling point of said hydrocarbon polystyrene non-solvent; washing with a mixture of about 50% to about 90% by weight of said hydrocarbon polystyrene non-solvent and about 10% to about 50% by weight of benzene or a second solvent comprising the first solvent or the second solvent defined above, and mixtures thereof, to obtain washed polystyrene and a second portion of a hydrocarbon waste solution; separating the washed polystyrene from a second portion of the hydrocarbon waste solution; The washed polystyrene washing with a third portion of a hydrocarbon polystyrene non-solvent at the boiling point of said hydrocarbon polystyrene non-solvent; or washing with a mixture of about 50% to about 90% by weight of said hydrocarbon polystyrene non-solvent and about 10% to about 50% by weight of benzene or a third solvent comprising the first solvent or the second solvent defined above, and mixtures thereof, to obtain a double washed polystyrene and a third portion of a hydrocarbon waste solution; separating the double washed polystyrene from a third portion of the hydrocarbon waste solution; and drying the double-washed polystyrene.

21. 1. A method for removing brominated polybutadiene polystyrene copolymer from polystyrene waste, comprising: combining the polystyrene waste with a solvent mixture comprising about 50% to about 90% by weight of benzene or a first solvent or a second solvent, and about 10% to about 50% by weight of a hydrocarbon polystyrene non-solvent to obtain a polystyrene / second solvent mixture and a solid comprising the copolymer, wherein the hydrocarbon polystyrene non-solvent is selected from the group consisting of C ５ ~C ８ obtaining a hydrocarbon; separating the solids containing the copolymer from the polystyrene / second solvent mixture; The first solvent is C １ and C ２ benzene substituted with one or two substituents each selected from alkyl, and mixtures thereof; The second solvent is C １ ~C ４ benzene substituted with 1 to 4, optionally 1 or 2, substituents each selected from alkyl, wherein at least one of said 1 to 4 substituents is isopropyl.

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