Crosslinked compositions with ethylene-based polymer and reversible crosslinker

Abstract

Embodiments are directed to a polyolefin elastomer comprising an ethylene-based polymer and at least one of bis(4-methacryloyloxyphenyl) disulfide (BiPheS methacrylate) and bis(4-methacryloyloxyethylcarbamoyloxyphenyl) disulfide (BiPheS extended methacrylate). Further embodiments are directed to reprocessing the polyolefin elastomer.

Description

CROSSLINKED COMPOSITIONS WITH ETHYLENE-BASED POLYMER AND REVERSIBLE CROSSLINKERCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 650,221 filed May 21, 2024, the contents of which are incorporated in their entirety herein.TECHNICAL FIELD

[0002] Embodiments of the present disclosure generally relate to crosslinked compositions and specifically relate to crosslinked compositions with ethylene-based polymer and reversible crosslinker.BACKGROUND

[0003] Crosslinked olefin-based polymers, and crosslinked ethylene-based polymers in particular, are well-known in myriad applications because of their mechanical properties, heat stability, and chemical resistance. Unfortunately, crosslinked ethylene-based polymer, also known as thermoset polymer, may be unable to be reprocessed and / or recycled due to the presence of the permanent crosslinked network within the ethylene-based polymer. Thus, the use of crosslinked ethylene-based polymer carriers concomitant environmental and sustainability concerns.

[0004] Accordingly, there is a need for improved crosslinked ethylene-based polymers that can be reprocessed and / or recycled.SUMMARY

[0005] The embodiments of the present disclosure meet this need by utilizing a reversible crosslinker, specifically bis(4-methacryloyloxyphenyl) disulfide (BiPheS methacrylate) and / or bis(4-methacryloyloxyethylcarbamoyloxyphenyl) disulfide (BiPheS extended methacrylate). This resulted in a crosslinked composition that gives a substantial network response upon crosslinking (e.g., storage modulus (E1) at 160 °C greater than 0.1 MPa) and recovers its storage modulus after successive compressive molding cycles (e.g., E' at 160 °C of 2ndmold greater than or about equal to E' at 160 °C of 1stmold), thereby providing a reprocessable and / or recyclable crosslinked ethylene-based polymer.

[0006] In one embodiment, a crosslinked composition comprises: an ethylene-based polymer; and at least one of bis(4-methacryloyloxyphenyl) disulfide (BiPheS methacrylate) and bis(4-methacryloyloxyethylcarbamoyloxyphenyl) disulfide (BiPheS extended methacrylate).

[0007] In another embodiment, a process comprises: heating a first article to a reprocessing temperature; forming, at the reprocessing temperature, the first article into a re-processable ethylene-based polymer composition; shaping, at the reprocessing temperature, the reprocessable ethylene-based composition into a re-processed pre-form; cooling the reprocessed pre-form to below the reprocessing temperature; and forming a second article. The first article comprises a crosslinked composition, the crosslinked composition comprising: an ethylene-based polymer; and bis(4-methacryloyloxyphenyl) disulfide (BiPheS methacrylate) or bis(4-methacryloyloxyethylcarbamoyloxyphenyl) disulfide (BiPheS extended methacrylate). The second article comprises a re-crosslinked composition comprising: the ethylene-based polymer and the at least one of BiPheS methacrylate or the BiPheS extended methacrylate. The second article is different from the first article.

[0008] Additional features and advantages will be set forth in the detailed description, which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows and the claims.

[0009] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter.DETAITED DESCRIPTION

[0010] Specific embodiments of the present application will now be described. The disclosure may be embodied in different forms and should not be construed as limited to the embodiments set forth in this disclosure. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subject matter to those skilled in the art.

[0011] DEFINITIONS

[0012] Unless stated to the contrary, implicit from the context, or customary in the art, all test methods are current as of the filing date of this disclosure.

[0013] The amount of a component (e.g., ethylene-based polymer, BiPheS methacrylate, BiPheS extended methacrylate, and free-radical initiator) in a crosslinkable polymer compositions or a crosslinked composition is provided herein in weight percent (wt%), based on a total weight of the crosslinkable polymer composition or the crosslinked composition, unless otherwise noted.

[0014] Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0015] The terms "comprising", "including", "having”, and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term, "consisting essentially of’ excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability. The term "consisting of’ excludes any component, step or procedure, not specifically delineated or listed.

[0016] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percentages are based on weight.

[0017] The term “composition,” as used herein, refers to a mixture of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0018] All references to the Periodic Table of the Elements herein shall refer to the Periodic Table of the Elements, published and copyrighted by CRC Press, Inc., 2003. Also, any references to a Group or Groups shall be to the Group or Groups reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups.

[0019] The term "ethylene-based polymer," as used herein, refers to a polymer that contains more than 50 mole percent polymerized ethylene monomer (based on the total amount of polymerizable monomers) and, optionally, may contain at least one comonomer. Ethylenebased polymer includes ethylene homopolymer, and ethylene copolymer (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" may be used interchangeably. Nonlimiting examples of ethylene-based polymer (polyethylene) include low density polyethylene (EDPE) and linear polyethylene. Nonlimiting examples of linear polyethylene include linear low density polyethylene (EEDPE), ultra low density polyethylene (UEDPE), very low density polyethylene (VEDPE), multi-component ethylene-based copolymer (EPE), ethylene / a-olefin multi-block copolymers (also known as olefin block copolymer (OBC)), substantially linear, or linear, plastomers / elastomers, and high density polyethylene (HDPE). Generally, polyethylene may be produced in gas-phase, fluidized bed reactors, liquid phase slurry process reactors, or liquid phase solution process reactors, using a heterogeneous catalyst system, such as Ziegler- Natta catalyst, a homogeneous catalyst system, comprising Group 4 transition metals and ligand structures such as metallocene, non-metallocene metal-centered, heteroaryl, heterovalent aryloxyether, phosphinimine, and others. Combinations of heterogeneous and / or homogeneous catalysts also may be used in either single reactor or dual reactor configurations.

[0020] The term “ethylene plastomers / elastomers,” as used herein, refer to substantially linear, or linear, ethylene / a-olefin copolymers containing homogenous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C3- C10 a-olefin comonomer. Ethylene plastomers / elastomers have a density from 0.970 g / cm3to 0.917 g / cm3. Nonlimiting examples of ethylene plastomers / elastomers include AFFINITY™ plastomers and elastomers (available from The Dow Chemical Company), EXACT Plastomers (available from ExxonMobil Chemical), TAFMER™ (available from Mitsui), NEXELENE™ (available from SK Chemicals Co.), and LUCENE™ (available from LG Chem Ltd.).

[0021] The term “high density polyethylene (HDPE),” as used herein, refers to an ethylene homopolymer or an ethylene / a-olefin copolymer with at least one C4-C10 a-olefin comonomer, or C4-C8 a-olefin comonomer and a density from 0.940 g / cm3, or 0.945 g / cm3, or 0.950 g / cm3, or 0.953 g / cm3to 0.955 g / cm3, or 0.960 g / cm3, or 0.965 g / cm3, or 0.970g / cm3, or 0.975 g / cm3, or 0.980 g / cm3. The HDPE can be a monomodal copolymer or a multimodal copolymer. A "monomodal ethylene copolymer" is an ethylene / a-olefin copolymer that has one distinct peak in a gel permeating chromatography (GPC) showing the molecular weight distribution. A “multimodal ethylene copolymer” is an ethylene / C4-Cio a- olefin copolymer that has at least two distinct peaks in a GPC showing the molecular weight distribution. Multimodal includes copolymer have two peaks (bimodal) as well as copolymer having more than two peaks. Nonlimiting examples of HDPE include DOW High Density Polyethylene (HDPE) Resins (available from The Dow Chemical Company), EEITE™ Enhanced Polyethylene Resins (Available from The Dow Chemical Company), CONTINUUM™ Bimodal Polyethylene Resins (available from The Dow Chemical Company), EUPOEEN™ (available from LyondellBasell), as well as HDPE products from Borealis, Ineos, and ExxonMobil.

[0022] The term “linear low density polyethylene (EEDPE),” as used herein, refers to a linear ethylene / a-olefin copolymer containing heterogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C3- C10 a-olefin, or C4-C8 a-olefin, comonomer. EEDPE is characterized by little, if any, long chain branching, in contrast to conventional LDPE. LLDPE has a density from 0.910 g / cm3to less than 0.940 g / cm3. Nonlimiting examples of LLDPE include TUFLIN™ linear low density polyethylene resins (available from The Dow Chemical Company), DOWLEX™ polyethylene resins (available from the Dow Chemical Company), and MARLEX™ polyethylene (available from Chevron Phillips).

[0023] The term “low density polyethylene” (or “LDPE”) consists of ethylene homopolymer, or ethylene / a-olefin copolymer comprising at least one C3-C10 a-olefm, or C4- Cs a-olefin, that has a density from 0.915 g / cm3to less than 0.940 g / cm3and contains long chain branching with broad MWD. LDPE is typically produced by way of high pressure free radical polymerization (tubular reactor or autoclave with free radical initiator). Nonlimiting examples of LDPE include MARFLEX™ (Chevron Phillips), LUPOLEN™ (LyondellBasell), as well as LDPE products from Borealis, Ineos, and ExxonMobil.

[0024] The term “heteroatom,” as used herein, refers to an atom other than carbon or hydrogen. The heteroatom can be a non-carbon atom from Groups IV, V, VI and VII of the Periodic Table. Nonlimiting examples of heteroatoms include F, N, O, P, B, S, and Si.

[0025] The term “hydrocarbon,” as used herein, refers to a compound containing only hydrogen atoms and carbon atoms. A "hydrocarbonyl" (or "hydrocarbonyl group") is a hydrocarbon having a valence (typically univalent). A hydrocarbon can have a linear structure, a cyclic structure, or a branched structure.

[0026] The terms “olefin-based polymer,” or “polyolefin,” as used herein, refer to polymer that contains more than 50 mole percent polymerized olefin monomer (based on total amount of polymerizable monomers), and optionally, may contain at least one comonomer. Nonlimiting examples of olefin-based polymer include ethylene-based polymer and propylene-based polymer.

[0027] The term “polymer,” as used herein, refers to a compound prepared by polymerizing monomers, whether of the same or a different type, that in polymerized form provide the multiple and / or repeating “units” or “mer units” that make up a polymer. The generic term polymer thus embraces the term homopolymer, usually employed to refer to polymers prepared from only one type of monomer, and the term copolymer, usually employed to refer to polymers prepared from at least two types of monomers. It also embraces all forms of copolymer, e.g., random, block, etc. The terms “ethylene / a-olefin polymer” and “propylene / a-olefin polymer” are indicative of copolymer as described above prepared from polymerizing ethylene or propylene respectively and one or more additional, polymerizable a-olefm monomer. It is noted that although a polymer is often referred to as being “made of’ one or more specified monomers, “based on” a specified monomer or monomer type, “containing” a specified monomer content, or the like, in this context, the term “monomer” is understood to be referring to the polymerized remnant of the specified monomer and not to the unpolymerized species. In general, polymers herein are referred to as being based on “units” that are the polymerized form of a corresponding monomer.

[0028] EMBODIMENTS

[0029] Embodiments of the present disclosure are directed to a crosslinked composition comprising an ethylene-based polymer and at least one of BiPheS methacrylate and BiPheS extended methacrylate. The crosslinked compositions may be formed from a crosslinkable polymer composition comprising the ethylene-based polymer, the at least one of BiPheS methacrylate and BiPheS extended methacrylate, and a radical initiator. That is, thecrosslinked composition may be the reaction product of crosslinking the crosslinkable polymer composition.

[0030] Ethylene-based Polymer

[0031] Ethylene-based polymer imparts desirable mechanical properties, heat stability, and chemical resistance to the crosslinked compositions described herein.

[0032] The ethylene-based polymer may be an ethylene homopolymer, an ethylene / Cs-Cio a-olefin copolymer, or an ethylene C4-C8 a-olefin copolymer. In embodiments, the ethylenebased polymer may comprise a melt index (MI) from 0.1 g / 10 min to 100 g / 10 min, from 0.1 g / 10 min to 50 g / 10 min, from 0.1 g / 10 min to 25 g / 10 min, from 0.1 g / 10 min to 10 g / 10 min, from 0.1 g / 10 min to 5 g / 10 min, from 1 g / 10 min to 100 g / 10 min, from 1 g / 10 min to 50 g / 10 min, from 1 g / 10 min to 25 g / 10 min, from 1 g / 10 min to 10 g / 10 min, from 1 g / 10 min to 5 g / 10 min, from 10 g / 10 min to 100 g / 10 min, from 10 g / 10 min to 50 g / 10 min, from 10 g / 10 min to 25 g / 10 min, from 25 g / 10 min to 100 g / 10 min, from 25 g / 10 min to 50 g / 10 min, or even from 50 g / 10 min to 100 g / 10 min, or any and all sub-ranges formed from any of these endpoints.

[0033] Nonlimiting examples of suitable ethylene-based polymer may include ethylene plastomer / elastomer, high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ethylene / a-olefin multi-block copolymer, and combinations thereof.

[0034] In embodiments, the ethylene-based polymer comprises ethylene plastomer / elastomer.

[0035] In embodiments, the ethylene-based polymer comprises HDPE.

[0036] In embodiments, the ethylene-based polymer comprises LLDPE.

[0037] In embodiments, the ethylene-based polymer comprises LDPE.

[0038] In embodiments, the ethylene-based polymer comprises ethylene / a-olefin multiblock copolymer. The term "ethylene / a-olefin multi-block copolymer" refers to an ethylene / C4-C8a-olefin multi-block copolymer consisting of ethylene and one copolymerizable C4-C8 a-olefin comonomer in polymerized form (and optional additives), the polymer characterized by multiple blocks or segments of two polymerized monomer units differing in chemical or physical properties, the blocks joined (or covalently bonded) in a linear manner, that is, a polymer comprising chemically differentiated units which are joinedend-to-end with respect to polymerized ethylenic functionality. Ethylene / a-olefin multiblock copolymer includes block copolymer with two blocks (di-block) and more than two blocks (multi-block). The C4-C8 a-olefin may be selected from butene, hexene, and octene. The ethylene / a-olefin multi-block copolymer may be void of, or otherwise exclude, styrene (i.e., is styrene-free), and / or vinyl aromatic monomer, and / or conjugated diene. When referring to amounts of "ethylene" or "comonomer" in the copolymer, it is understood that this refers to polymerized units thereof. In some embodiments, the ethylene / a-olefin multiblock copolymer may be represented by the following formula: (AB)n; where n is at least 1, preferably an integer greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, "A" represents a hard block or segment, and "B" represents a soft block or segment. The As and Bs are linked, or covalently bonded, in a substantially linear fashion, or in a linear manner, as opposed to a substantially branched or substantially star-shaped fashion. In other embodiments, A blocks and B blocks are randomly distributed along the polymer chain. In other words, the block copolymers usually do not have a structure as follows: AAA-AA-BBB-BB. In embodiments, the ethylene / a-olefin multi-block copolymer may not have a third type of block, which comprises different comonomer(s). In other embodiments, each of block A and block B may have monomers or comonomers substantially randomly distributed within the block. In other words, neither block A nor block B comprises two or more sub-segments (or sub-blocks) of distinct composition, such as a tip segment, which has a substantially different composition than the rest of the block.

[0039] In embodiments, ethylene may comprise the majority mole fraction of the whole ethylene / a-olefin multi-block copolymer (i.e., ethylene comprises at least 50 wt% of the whole ethylene / a-olefin multi-block copolymer). In embodiments, ethylene may comprise at least 60 wt%, at least 70 wt%, or at least 80 wt%, with the substantial remainder of the whole ethylene / a-olefin multi-block copolymer comprising the C4-C8 a-olefin comonomer. In embodiments, the ethylene / a-olefin multi-block copolymer may comprise 50 wt% to 90 wt% ethylene, 60 wt% to 85 wt% ethylene, or 65 wt% to 80 wt% ethylene. In embodiments including ethylene / octene multi-block copolymers, the composition may comprise an ethylene content greater than 80 wt% of the whole ethylene / octene multi-block copolymer and an octene content of from 10 wt% to 15 wt%, or from 15 wt% to 20 wt% of the whole multi-block copolymer.

[0040] The ethylene / a-olefin multi-block copolymer may include various amounts of "hard" segments and "soft" segments. "Hard" segments are blocks of polymerized units in which ethylene is present in an amount greater than 90 wt%, 95 wt%, greater than 95 wt%, or greater than 98 wt%, based on the weight of the polymer, up to 100 wt%. For example, the comonomer content (content of monomers other than ethylene) in the hard segments may be less than 10 wt%, or 5 wt%, or less than 5 wt%, or even less than 2 wt%, based on the weight of the polymer, and can be as low as zero. In some embodiments, the hard segments may include all, or substantially all, units derived from ethylene. "Soft" segments are blocks of polymerized units in which the comonomer content (content of monomers other than ethylene) is greater than 5 wt%, greater than 8 wt%, greater than 10 wt%, or greater than 15 wt%, based on the weight of the polymer. In an embodiment, the comonomer content in the soft segments may be greater than 20 wt%, greater than 25 wt%, greater than 30 wt%, greater than 35 wt%, greater than 40 wt%, greater than 45 wt%, greater than 50 wt%, or even greater than 60 wt%, and can be up to 100 wt%.

[0041] The soft segments may be present in an ethylene / a-olefin multi-block copolymer from 1 wt% to 99 wt%, from 5 wt% to 95 wt%, from 10 wt% to 90 wt%, from 15 wt% to 85 wt%, from 20 wt% to 80 wt%, from 25 wt% to 75 wt%, from 30 wt% to 70 wt%, from 35 wt% to 65 wt%, from 40 wt% to 60 wt%, or even from 45 wt% to 55 wt%, or any and all sub-ranges formed from any of these endpoints, of the total weight of the ethylene / a-olefin multi-block copolymer. Conversely, the hard segments may be present in similar ranges. The soft segment weight percentage and the hard segment weight percentage may be calculated based on data obtained from DSC or NMR. Such methods and calculations are disclosed in, for example, U.S. Patent No. 7,608,668, which is incorporated by reference herein in its entirety.

[0042] The ethylene / a-olefin multi-block copolymer comprises two or more chemically distinct regions or segments (referred to as "blocks") joined (or covalently bonded) in a linear manner, that is, it contains chemically differentiated units which are joined end-to-end with respect to polymerized ethylenic functionality, rather than in pendent or grafted fashion. In embodiments, the blocks may differ in the amount or type of incorporated comonomer, density, amount of crystallinity, crystallite size attributable to a polymer of such composition, type or degree of tacticity (isotactic or syndiotactic), regio-regularity or regio-irregularity, amount of branching (including long chain branching or hyper-branching), homogeneity or any other chemical or physical property. Compared to conventional block interpolymers,including interpolymers produced by sequential monomer addition, fluxional catalysts, or anionic polymerization techniques, the present ethylene / a-olefin multi-block copolymer is characterized by unique distributions of both polymer polydispersity (PDI or Mw / Mn or MWD), polydisperse block length distribution, and / or polydisperse block number distribution, due, for example, to the effect of the shuttling agent(s) in combination with multiple catalysts used in their preparation.

[0043] In embodiments, the ethylene / a-olefin multi-block copolymer may be produced in a continuous process and possesses a polydispersity index (Mw / Mn) from 1.7 to 3.5, from 1.8 to 3.0, from 1.8 to 2.5, or even from 1.8 to 2.2, or any and all sub-ranges formed from any of these endpoints. When produced in a batch or semi-batch process, the ethylene / a-olefin multiblock copolymer may possess Mw / Mn from 1.0 to 3.5, from 1.3 to 3.0, from 1.4 to 2.5, or even from 1.4 to 2.0, or any and all sub-ranges formed from any of these endpoints.

[0044] In addition, the ethylene / a-olefin multi-block copolymer may possess a PDI (or Mw / Mn} fitting a Schultz-Flory distribution rather than a Poisson distribution. The ethylene / a-olefin multi-block copolymer may have both a polydisperse block distribution as well as a polydisperse distribution of block sizes. This results in the formation of polymer products having improved and distinguishable physical properties. The theoretical benefits of a polydisperse block distribution have been previously modeled and discussed in Potemkin, Physical Review E (1998) 57 (6), pp. 6902-6912, and Dobrynin, J. Chem. Phvs. (1997) 107 (21), pp 9234-9238, which is incorporated by reference herein in its entirety.

[0045] In embodiments, the present ethylene / a-olefin multi-block copolymer may possess almost probable distribution of block lengths.

[0046] In other embodiments, the ethylene / a-olefin multi-block copolymer, for example, those made in a continuous, solution polymerization reactor, may possess a most probable distribution of block lengths. In embodiments, ethylene / a-olefin multi-block copolymers may be defined as having:(A) Mw / Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams / cubic centimeter, wherein the numerical values of Tm and d correspond to the relationship:Tm > -2002.9 + 4538.5(d) - 2422.2(d)2, and / or(B) Mw / Mn from about 1.7 to about 3.5, and is characterized by a heat of fusion, DH in J / g, and a delta quantity, DT, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest Crystallization Analysis Fractionation ("CRYSTAF") peak, wherein the numerical values of DT and DH have the following relationships:DT > -0.1299 DH + 62.81 for DH greater than zero and up to 130 J / gDT > 48 °C for DH greater than 130 J / g wherein the CRYSTAF peak is determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer has an identifiable CRYSTAF peak, then the CRYSTAF temperature is 30 °C; and / or(C) elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded film of the ethylene / a-olefin interpolymer, and has a density, d, in grams / cubic centimeter, wherein the numerical values of Re and d satisfy the following relationship when ethylene / a-olefin interpolymer is substantially free of crosslinked phase:Re > 1481 - 1629(d); and / or(D) has a molecular fraction which elutes between 40 °C and 130 °C when fractionated using TREF, characterized in that the fraction has a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer has the same comonomer(s) and has a melt index, density and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene / a-olefin interpolymer; and / or(E) has a storage modulus at 25 °C, G'(25 °C), and a storage modulus at 100 °C, G'(100 °C), wherein the ratio of G'(25 °C) to G'(100 °C) is in the range of 1 :1 to 9:1.

[0047] The ethylene / a-olefin multi-block copolymer may also have:(F) a molecular fraction which elutes between 40 °C and 130 °C when fractionated using TREF, characterized in that the fraction has a block index of at least 0.5 and up to 1 and a molecular weight distribution, Mw / Mn, greater than 1.3; and / or(G) average block index greater than zero and up to 1.0 and a molecular weight distribution, Mw / Mn greater than 1.3.

[0048] It is understood that the ethylene / a -olefin multi-block copolymer may have one, some, all, or any combination of properties (A)-(G). Block index may be determined as described in detail in U.S. Patent No. 7,608,668, which is incorporated by reference herein in its entirety.

[0049] In embodiments, the ethylene / a-olefin multi-block copolymer may have hard segments and soft segments, may be styrene-free, may consist of only (i) ethylene and (ii) a C4-C8 a-olefin or C8 a-olefin (and optional additives), and may be defined as having a Mw / Mn from 1.7 to 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams / cubic centimeter, wherein the numerical values of Tm and d correspond to the relationship:Tm > -2002.9 + 4538.5(d) - 2422.2(d)2, where the density, d, is from 0.850 g / cm3, or 0.860 g / cm3, or 0.870 g / cm3to 0.875 g / cm3, or 0.877 g / cm3, or 0.880 g / cm3, or 0.890 g / cm3; and the melting point, Tm, is from 110 °C, or 115 °C, or 120 °C to 125 °C, or 130 °C, or 135 °C.

[0050] In embodiments, the ethylene / a-olefin multi-block copolymer is an ethylene / 1- octene multi-block copolymer (consisting only of ethylene and octene comonomer) and has one, some, or all of the following properties:(i) a Mw / Mn from 1.7, or 1.8 to 2.2, or 2.5, or 3.5; and / or(ii) a density from 0.860 g / cm3, or 0.865 g / cm3, to 0.870 g / cm3, or 0.877 g / cm3, or 0.880 g / cm3; and / or(iii) a melting point, Tm, from 115 °C, or 118 °C, or 119 °C, or 120 °C to 121 °C, or 123 °C, or 125 °C; and / or(iv) a melt index (MI) from 0.1 g / 10 min, or 0.5 g / 10 min to 1.0 g / 10 min, or 2.0 g / 10 min, or 5 g / 10 min, or 10 g / 10 min; and / or(v) from 50 to 85 wt% soft segment and from 40 to 15 wt% hard segment (based on total weight of the ethylene / octene multi-block copolymer); and / or(vi) from 10 mol%, or 13 mol%, or 14 mol%, or 15 mol% to 16 mol%, or 17 mol%, or 18 mol%, or 19 mol%, or 20 mol% octene in the soft segment; and / or(vii) from 0.5 mol%, or 1.0 mol%, or 2.0 mol%, or 3.0 mol% to 4.0 mol%, or 5 mol%, or 6 mol%, or 7 mol%, or 9 mol% octene in the hard segment; and / or(viii) an elastic recovery (Re) from 50%, or 60% to 70%, or 80%, or 90%, at 300% min'1deformation rate at 21 °C as measured in accordance with ASTM D 1708; and / or a polydisperse distribution of blocks and a polydisperse distribution of block sizes (hereafter referred to as multi-block copolymer properties (i)-(ix)).

[0051] In embodiments, the ethylene / a-olefm multi-block copolymer may be an ethylene / octene multi-block copolymer. For example, an ethylene / octene multi-block copolymer is sold under the tradename INFUSE™, available from The Dow Chemical Company, Midland, Michigan, USA.

[0052] The ethylene / a-olefin multi-block copolymer may be produced via a chain shuttling process such as described in U.S. Patent Nos. 7,858,706; 7,608,668; 7,893,166; and 7,947,793, which are incorporated by reference herein in their entireties.

[0053] The ethylene / a-olefm multi-block copolymer may include more than one ethylene / a- olefm multi-block copolymer.

[0054] In embodiments, the ethylene-based polymer may be a polar ethylene-based polymer. A “polar ethylene-based polymer,” as used herein, is an ethylene-based polymer composed of (i) ethylene monomer, (ii) a comonomer that contains a heteroatom, and (iii) an optional termonomer (that may or may not contain a heteroatom). Stated differently, the polar ethylene-based polymer is not a hydrocarbon. Nonlimiting examples of comonomers with a heteroatom include carbon monoxide, carboxylic acids, esters, alkyl acrylates having 1 to 30 carbon atoms, methacrylate esters having 1 to 30 carbon atoms, vinyl siloxanes having 1 to 16 carbon atoms and halogens. Non-limiting examples of suitable polar ethylene-based polymer include ethylene / carboxylic acid copolymer and metal-salt partially neutralized ionomers derived thereof, ethylene / acrylic acid copolymer (EAA), ethylene / methacrylic acid copolymer (EMAA), ethylene / vinyl(trimethoxy)silane copolymer (EVTMS), ethylene / vinyl acetate copolymer (EVA), ethylene / methyl acrylate (EMA), ethylene / ethyl acrylate copolymer (EEA), ethylene / butyl acrylate copolymer (EBA), ethylene / carbon monoxide (ECO), ethylene / glycidyl methacrylate (E / GMA), ethylene / methyl methacrylate copolymer, ethylene / butyl methacrylate copolymer, ethylene / stearylacrylate copolymer, ethylene / stearylmethacrylate copolymer, ethylene / octylacrylate copolymer, ethylene / 2- ethylhexylacrylate copolymer, ethylene / dodecylacrylate copolymer, polyvinyldichloride (PVCD), ethylene / maleic anhydride copolymer (EMAH), polyvinylchloride (PVC), andcombinations thereof. Additional nonlimiting terpolymer examples include ethylene / carboxylic acid / acrylate terpolymers and metal-salt partially neutralized ionomers derived thereof, ethylene / methyl acrylate / vinyl(trimethoxy)silane terpolymer copolymer (EMAVTMS), ethylene / ethyl acrylate / vinyl(trimethoxy)silane terpolymer copolymer (EEAVTMS), ethylene / butyl acrylate / vinyl(trimethoxy)silane terpolymer copolymer (EBAVTMS), ethylene / methyl acrylate / glycidyl methacrylate (EMAGMA) ethylene / butyl acrylate / glycidyl methacrylate (EBAGMA), ethylene / vinyl acetate / maleic anhydride terpolymer (EEAMAEI), ethylene ethyl acrylate / maleic anhydride (EEAMAEI) terpolymer, and combinations thereof.

[0055] In embodiments, the polar ethylene-based polymer may comprise EVA.

[0056] The crosslinkable polymer composition and the resulting crosslinked composition may comprise a minimum amount of ethylene-based polymer (e.g., greater than or equal to 70 wt%) to ensure the crosslinked composition has desirable mechanical properties, heat stability, and chemical resistance. The amount of ethylene-based polymer may be limited (e.g., less than or equal to 96.5 wt%) to ensure that enough reversible crosslinker is present to ensure reprocessability and / or recyclability of the crosslinked composition. Accordingly, in embodiments, the crosslinkable polymer composition and the resulting crosslinked composition may comprise from 70 wt% to 96.5 wt% of the ethylene-based polymer. In embodiments, the amount of ethylene-based polymer in the crosslinkable polymer composition and the resulting crosslinked composition may be greater than or equal to 70 wt%, greater than or equal to 75 wt%, greater than or equal to 80 wt%, greater than or equal to 85 wt%, or even greater than or equal to 90 wt%. In embodiments, the amount of ethylenebased polymer in the crosslinkable polymer composition and the resulting crosslinked composition may be less than or equal to 96.5 wt%, less than or equal to 96 wt%, less than or equal to 95 wt%, or even less than or equal to 94 wt%. In embodiments, the amount of ethylene-based polymer in the crosslinkable polymer composition and the resulting crosslinked composition may be from 70 wt% to 96.5 wt%, from 70 wt% to 96 wt%, from 70 wt% to 95 wt%, from 70 wt% to 94 wt%, from 75 wt% to 96.5 wt%, from 75 wt% to 96 wt%, from 75 wt% to 95 wt%, from 75 wt% to 94 wt%, from 80 wt% to 96.5 wt%, from 80 wt% to 96 wt%, from 80 wt% to 95 wt%, from 80 wt% to 94 wt%, from 85 wt% to 96.5 wt%, from 85 wt% to 96 wt%, from 85 wt% to 95 wt%, from 85 wt% to 94 wt%, from 90 wt% to 96.5wt%, from 90 wt% to 96 wt%, from 90 wt% to 95 wt%, or even from 90 wt% to 94 wt%, or any and all sub-ranges formed from any of these endpoints.

[0057] Reversible Crosslinker

[0058] As described in further detail below, reversible crosslinker such as BiPheS methacrylate and / or BiPheS extended methacrylate imparts reprocessability and / or recyclability to the crosslinked composition.

[0059] In embodiments, the crosslinkable polymer composition and the resulting crosslinked composition may comprise at least one of BiPheS methacrylate and BiPheS extended methacrylate. BiPheS methacrylate has Structure 1 shown below and BiPheS extended methacrylate has Structure 2 shown below:STRUCTURE 2

[0060] While not wishing to be bound by theory, the amount (in weight percent) of the reversible crosslinker included in the crosslinkable polymer composition and the resulting crosslinked composition may be dependent on properties of the ethylene-based polymer (e.g., amount of units amenable to grafting) being used therein. As such, a given amount of reversible crosslinker used with one type of ethylene-based polymer to provide desired results (e.g., a substantial network response upon crosslinking (e.g., storage modulus (E1) at 160 °C greater than 0.1 MPa) and recovers its storage modulus after successive compressive molding cycles (e.g., E1at 160 °C of 2ndmold greater than or about equal to E1at 160 °C of 1stmold)) may not produce desirable results when used with another type of ethylene-based polymer.

[0061] The crosslinkable polymer composition and the resulting crosslinked composition may comprise a minimum amount of BiPheS methacrylate and / or BiPheS extended methacrylate (e.g., greater than or equal to 3.5 wt%) to impart reprocessability and / or recyclability to the crosslinked composition. The amount of BiPheS methacrylate and / or BiPheS extended methacrylate may be limited (e.g., less than or equal to 20 wt%) to prevent undesirable aggregation or homopolymerization of the reversible crosslinker rather than contributing to the network structure, which may lead to undesirable properties. Accordingly, in embodiments, the crosslinkable polymer composition and the resulting crosslinked composition may comprise from 3.5 wt% to 20 wt% of the at least one of BiPheS methacrylate and BiPheS extended methacrylate. In embodiments, the amount of the at least one of BiPheS methacrylate and BiPheS extended methacrylate in the crosslinkable polymer composition and the resulting crosslinked composition may be greater than or equal to 3.5 wt%, greater than or equal to 3.75 wt%, greater than or equal to 4.0 wt%, greater than or equal to 4.25 wt%, or even greater than or equal to 4.5 wt%. In embodiments, the amount of the at least one of BiPheS methacrylate and BiPheS extended methacrylate in the crosslinkable polymer composition and the resulting crosslinked composition may be less than or equal to 20 wt%, less than or equal to 15 wt%, less than or equal to 10 wt%, less than or equal to 9 wt%, less than or equal to 8 wt%, less than or equal to 7 wt%, less than or equal to 6 wt%, or even less than or equal to 5 wt%. In embodiments, the amount of the at least one of BiPheS methacrylate and BiPheS extended methacrylate in the crosslinkable polymer composition and the resulting crosslinked composition may be from 3.5 wt% to 20 wt%, from 3.5 wt% to 15 wt%, from 3.5 wt% to 10 wt%, from 3.5 wt% to 9 wt%, from 3.5 wt% to 8 wt%, from 3.5 wt% to 7 wt%, from 3.5 wt% to 6 wt%, from 3.5 wt% to 5 wt%, from 3.75 wt% to 20 wt%, from 3.75 wt% to 15 wt%, from 3.75 wt% to 10 wt%, from 3.75 wt% to 9 wt%, from 3.75 wt% to 8 wt%, from 3.75 wt% to 7 wt%, from 3.75 wt% to 6 wt%, from 3.75 wt% to 5 wt%, from 4 wt% to 20 wt%, from 4 wt% to 15 wt%, from 4 wt% to 10 wt%, from 4 wt% to 9 wt%, from 4 wt% to 8 wt%, from 4 wt% to 7 wt%, from 4 wt% to 6 wt%, from 4 wt% to 5 wt%, from 4.25 wt% to 20 wt%, from 4.25 wt% to 15 wt%, from 4.25 wt% to 10 wt%, from 4.25 wt% to 9 wt%, from 4.25 wt% to 8 wt%, from 4.25 wt% to 7 wt%, from 4.25 wt% to 6 wt%, from 4.25 wt% to 5 wt%, from 4.5 wt% to 20 wt%, from 4.5 wt% to 15 wt%, from 4.5 wt% to 10 wt%, from 4.5 wt% to 9 wt%, from 4.5 wt% to 8 wt%, from 4.5 wt% to7 wt%, from 4.5 wt% to 6 wt%, or even from 4.5 wt% to 5 wt%, or any and all sub-ranges formed from any of these endpoints.

[0062] Free Radical Initiator

[0063] Free radical initiator enables crosslinking of the crosslinkable polymer composition, thereby forming the crosslinked composition. The free radical initiator decomposes whereby forming free radicals and the reaction of primary radicals with polymer composition.

[0064] In embodiments, the free radical initiator may comprise an organic peroxide. Nonlimiting examples of suitable organic peroxide include bis( 1,1 -dimethylethyl) peroxide; bis( 1,1 -dimethylpropyl) peroxide; 2,5-dimethyl-2,5-bis(l,l-dimethylethylperoxy) hexane; 2,5 -dimethyl-2,5 -bis( 1 , 1 -dimethylethylperoxy) hexyne; 4,4-bis( 1 , 1 -dimethylethylperoxy) valeric acid; butyl ester; l,l-bis(l,l-dimethylethylperoxy)-3,3,5-trimethylcyclohexane; benzoyl peroxide; tert-butyl peroxybenzoate; di-tert-amyl peroxide (“DTAP”), bis(a-t-butyl- peroxyisopropyl) benzene (“BIBP”); isopropylcymyl t-butyl peroxide; t- butylcumylperoxide; di-t-butyl peroxide; 2,5-bis(t-butylperoxy)-2,5-dimethylhexane; 2,5- bis(tbutylperoxy)-2,5-dimethylhexyne-3,l,l-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane; isopropylcumyl cumylperoxide; butyl 4,4-di(tert-butylperoxy) valerate; di(isopropylcumyl) peroxide; dicumyl peroxide, and combinations thereof. In embodiments, the free radical initiator may comprise dicumyl peroxide.

[0065] While not wishing to be bound by theory, the amount (in weight percent) of the free radical initiator included in the crosslinkable polymer composition and the resulting crosslinked composition may be dependent on properties of the ethylene-based polymer (e.g., molecular weight, viscosity, and / or comonomer identity and content) being used therein. As such, a given amount of free radical initiator used with one type of ethylene-based polymer to provide desired results (e.g., a substantial network response upon crosslinking (e.g., storage modulus (E1) at 160 °C greater than 0.1 MPa) and recovers its storage modulus after successive compressive molding cycles (e.g., E' at 160 °C of 2ndmold greater than or about equal to E' at 160 °C of 1stmold)) may not produce desirable results when used with another type of ethylene-based polymer.

[0066] The crosslinkable polymer composition may comprise a minimum amount of free radical initiator (e.g., greater than or equal to 0.4 wt%) to initiate crosslinking of the crosslinkable polymer composition. The amount of the free radical initiator may be limited(e.g., less than or equal to 2 wt%) to prevent formation of permanent crosslinks incapable of dynamic chemistry. Accordingly, in embodiments, the crosslinkable polymer composition may comprise from 0.4 wt% to 2 wt% free radical initiator. In embodiments, the amount of the free radical initiator in the crosslinkable polymer composition may be greater than or equal to 0.4 wt%, greater than or equal to 0.5 wt%, greater than or equal to 0.6 wt%, greater than or equal to 0.7 wt%, greater than or equal to 0.8 wt%, or even greater than or equal to 0.9 wt%. In embodiments, the amount of the free radical initiator in the crosslinkable polymer composition may be less than or equal to 2 wt%, less than or equal to 1.75 wt%, less than or equal to 1.5 wt%, less than or equal to 1.25 wt%, or even less than or equal to 1 wt%. In embodiments, the amount of the free radical initiator in the crosslinkable polymer composition may be from 0.4 wt% to 2 wt%, from 0.4 wt% to 1.75 wt%, from 0.4 wt% to 1.5 wt%, from 0.4 wt% to 1.25 wt%, from 0.4 wt% to 1 wt%, from 0.5 wt% to 2 wt%, from 0.5 wt% to 1.75 wt%, from 0.5 wt% to 1.5 wt%, from 0.5 wt% to 1.25 wt%, from 0.5 wt% to 1 wt%, from 0.6 wt% to 2 wt%, from 0.6 wt% to 1.75 wt%, from 0.6 wt% to 1.5 wt%, from 0.6 wt% to 1.25 wt%, from 0.6 wt% to 1 wt%, from 0.7 wt% to 2 wt%, from 0.7 wt% to 1.75 wt%, from 0.7 wt% to 1.5 wt%, from 0.7 wt% to 1.25 wt%, from 0.7 wt% to 1 wt%, from 0.8 wt% to 2 wt%, from 0.8 wt% to 1.75 wt%, from 0.8 wt% to 1.5 wt%, from 0.8 wt% to 1.25 wt%, from 0.8 wt% to 1 wt%, from 0.9 wt% to 2 wt%, from 0.9 wt% to 1.75 wt%, from 0.9 wt% to 1.5 wt%, from 0.9 wt% to 1.25 wt%, or even from 0.9 wt% to 1 wt%, or any and all sub-ranges formed from any of these endpoints.

[0067] In embodiments, the weight ratio of the reversible crosslinker to the free radical initiator may be from 3: 1 to 10:1, from 3:1 to 8:1, from 3:1 to 6:1, from 3.5:1 to 10:1, from 3.5:1 to 8:1, from 3.5:1 to 6:1, from 4:1 to 10:1, from 4:1 to 8:1, from 4: 1 to 6:1, from 5:1 to 10:1, from 5:1 to 8:1, from 5:1 to 6:1, from 6:1 to 10:1, or even from 6:1 to 8:1, or any and all sub-ranges formed from any of these endpoints.

[0068] Blend Component

[0069] In embodiments, the crosslinkable polymer composition and / or the crosslinked composition includes a blend component. Nonlimiting examples of suitable blend component include ethylene vinyl acetate (EVA), polyolefins (e.g., polyethylene other than the ethylenebased polymer crosslinked with reversible crosslinker and polypropylene), polymers (e.g., polystyrene, ABS, SBS and the like) and combinations thereof. Non-limiting examples of suitable polyolefins include polyethylene; polypropylene; polybutylene (e.g., polybutene- 1);polypentene- 1; polyhexene- 1; polyoctene- 1; polydecene- 1; poly-3 -methylbutene- 1 ; poly-4- methylpentene-1; polyisoprene; polybutadiene; poly- 1,5 -hexadiene; interpolymers derived from olefins; interpolymers derived from olefins and other polymers such as polyvinyl chloride, polystyrene, and polyurethane; and combinations thereof.

[0070] In an embodiment, the polyolefin is a homopolymer such as polyethylene, polypropylene, polybutylene, polypentene- 1, poly-3 -methylbutene- 1, poly-4-methylpentene- 1, polyisoprene, polybutadiene, poly- 1,5 -hexadiene, polyhexene- 1, polyoctene- 1 and polydecene-1.

[0071] Nonlimiting examples of suitable polyethylene as blend component (other than the ethylene-based polymer that is crosslinked with reversible crosslinker) include ultra low density polyethylene (ULDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), high molecular weight high density polyethylene (HMW-HDPE), ultra high molecular weight polyethylene (UHMW-PE) and combinations thereof. Nonlimiting examples of polypropylene include low density polypropylene (LDPP), high density polypropylene (HDPP), high-melt strength polypropylene (HMS-PP) and combination thereof. In an embodiment, the blend component is a high-melt strength polypropylene (HMS-PP), a low density polyethylene (LDPE) or a combination thereof.

[0072] Additives

[0073] The crosslinkable composition and / or the crosslinked composition may contain one or more optional additives. Nonlimiting examples of suitable additives include grafting initiators, cross-linking catalysts, blowing agent, blowing agent activators (e.g., zinc oxide, zinc stearate and the like), coagents (e.g., triallyl cyanurate), plasticizers, processing oils, processing aids, carbon black, colorants or pigments, stability control agents, nucleating agents, fillers, antioxidants, acid scavengers, ultraviolet (UV) stabilizers, flame retardants, lubricants, processing aids, extrusion aids, and combinations thereof. When present, the total amount of additive can be from greater than 0% to 80%, or from 0.001% to 70%, or from 0.01% to 60 %, or from 0.1 % to 50 %, or from 0.1 % to 40%, or from 0.1% to 20%, or from 0.1 % to 10 %, or from 0.1% to 5% of the total weight of the composition.

[0074] In embodiments, the crosslinkable composition and / or the crosslinked composition includes an antioxidant. Non-limiting examples of suitable antioxidants include aromatic orhindered amines such as alkyl diphenylamines, phenyl-a-naphthylamine, alkyl or aralkyl substituted phenyl-a-naphthylamine, alkylated p-phenylene diamines, tetramethyldiaminodiphenylamine and the like; phenols such as 2,6-di-t-butyl-4-methylphenol; 1,3,5- trimethyl-2,4,6-tris(3',5,-di-t-butyl-4,-hydroxybenzyl)benzene; tetrakis[(methylene(3,5 -di-t- butyl-4-hydroxyhydrocinnamate)]methane (e.g., IRGANOX™ 1010, from Ciba Geigy, NewYork); acryloyl modified phenols; octadecyl-3,5- di-t-butyl-4-hydroxycinnamate (e.g., IRGANOX 1076, commercially available from Ciba Geigy); phosphites and phosphonites; hydroxylamines; benzofuranone derivatives; and combinations thereof. When used, the amount of the antioxidant in the composition can be from greater than 0 to 5%, or from 0.0001 to 2.5%, or from 0.001 to 1%, or from 0.001 to 0.5% of the total weight of the composition.

[0075] In embodiments, the crosslinkable composition and / or the crosslinked composition includes a UV stabilizer. Non-limiting examples of suitable UV stabilizers include benzophenones, benzotriazoles, aryl esters, oxanilides, acrylic esters, formamidines, carbon black, hindered amines, nickel quenchers, hindered amines, phenolic antioxidants, metallic salts, zinc compounds and combinations thereof. When used, the amount of the UV stabilizer can be from greater than 0 to 5%, or from 0.01 % to 3 %, or from 0.1 % to 2 %, or from 0.1% to 1% of the total weight of the composition.

[0076] In embodiments, the crosslinkable composition and / or the crosslinked composition includes a colorant or a pigment. Non-limiting examples of suitable colorants or pigments include inorganic pigments such as metal oxides such as iron oxide, zinc oxide, and titanium dioxide, mixed metal oxides, carbon black, organic pigments such as anthraquinones, anthanthrones, azo and monoazo compounds, arylamides, benzimidazolones, BONA lakes, diketopyrrolo-pyrroles, dioxazines, disazo compounds, diarylide compounds, flavanthrones, indanthrones, isoindolinones, isoindolines, metal complexes, monoazo salts, naphthols, b- naphthols, naphthol AS, naphthol lakes, perylenes, perinones, phthalocyanines, pyranthrones, quinacridones, and quinophthalones, and combinations thereof. When used, the amount of the colorant or pigment in the composition can be from greater than 0 to 10%, or from 0.1% to 5 %, or from 0.25% to 2% of the total weight of the composition.

[0077] In embodiments, the crosslinkable composition and / or the crosslinked composition includes a filler. Nonlimiting examples of suitable fillers include talc, calcium carbonate, chalk, calcium sulfate, clay, kaolin, silica, glass, fumed silica, mica, wollastonite, feldspar, aluminum silicate, calcium silicate, alumina, hydrated alumina such as aluminatrihydrate, glass microsphere, ceramic microsphere, thermoplastic microsphere, barite, wood flour, glass fibers, carbon fibers, marble dust, cement dust, magnesium oxide, magnesium hydroxide, antimony oxide, zinc oxide, barium sulfate, titanium dioxide, titanates and combinations thereof.

[0078] In embodiments, the filler is barium sulfate, talc, calcium carbonate, silica, glass, glass fiber, alumina, titanium dioxide, or a mixture thereof. In a further embodiment, the filler is talc, calcium carbonate, barium sulfate, glass fiber or a mixture thereof. When used, the amount of the filler in the composition can be from greater than 0 to 80%, or from 0.1 to 60%, or from 0.5 to 40%, or from 1 to 30%, or from 10 to 40% of the total weight of the composition.

[0079] In embodiments, the crosslinkable composition and / or the crosslinked composition includes a lubricant. Nonlimiting examples of suitable lubricants include fatty alcohols and their dicarboxylic acid esters, fatty acid esters of short chain alcohols, fatty acids, fatty acid amides, metal soaps, oligomeric fatty acid esters, fatty acid esters of long-chain alcohols, montan waxes, polyethylene waxes, polypropylene waxes, natural and synthetic paraffin waxes, fluoropolymers and combinations thereof. When used, the amount of the lubricant in the composition can be from greater than 0% to 5%, or from 0.1 to 4%, or from 0.1% to 3% of the total weight of the composition.

[0080] In embodiments, the crosslinkable composition and / or the crosslinked composition includes an antistatic agent. Non-limiting examples of suitable antistatic agents include conductive fillers (e.g., carbon black, metal particles and other conductive particles), fatty acid esters (e.g., glycerol monostearate), ethoxylated alkylamines, diethanolamides, ethoxylated alcohols, alkylsulfonates, alkylphosphates, quaternary ammonium salts, alkylbetaines and combinations thereof. Where used, the amount of the antistatic agent in the composition can be from greater than 0 % to 5 %, or from 0.01 to 3 %, or from 0.1 to 2 % of the total weight of the composition.

[0081] In embodiments, the crosslinkable composition and / or the crosslinked composition includes a blowing agent. A "blowing agent" is a substance that is capable of producing a cellular structure in the composition via a foaming process. The blowing agent is used for foaming the crosslinked composition. Nonlimiting examples of suitable blowing agent include an inorganic physical blowing agent, such as air, argon, nitrogen, carbon dioxide,argon, helium, oxygen, and neon, and an organic physical blowing agent, such as an aliphatic hydrocarbon, e.g., propane, n- butane, isobutane, n-pentane, isopentane, and n-hexane, an alicyclic hydrocarbon, e.g., cyclohexane and cyclopentane, a halogenated hydrocarbon, e.g., chlorofluoromethane, trifluoromethane, 1,1 -difluoro ethane, 1,1,1,2-tetrafluoroethane, methyl chloride, ethyl chloride, and methylene chloride, and a dialkyl ether, e.g., dimethyl ether, diethyl ether, and methyl ethyl ether.

[0082] Non-limiting examples of suitable organic blowing agents include aliphatic hydrocarbons having 1-6 carbon atoms, aliphatic alcohols having 1-3 carbon atoms, and fully and partially halogenated aliphatic hydrocarbons having 1-4 carbon atoms. Non-limiting examples of suitable aliphatic hydrocarbons include methane, ethane, propane, n-butane, isobutane, n- pentane, isopentane, neopentane, and the like. Non-limiting examples of suitable aliphatic alcohols include methanol, ethanol, n-propanol, and isopropanol. Nonlimiting examples of suitable fully and partially halogenated aliphatic hydrocarbons include fluorocarbons, chlorocarbons, and chlorofluorocarbons. Non-limiting examples of suitable fluorocarbons include methyl fluoride, perfluoromethane, ethyl fluoride, 1,1 -difluoroethane (HFC152a), 1,1,1- trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoroethane, difluoromethane, perfluoroethane, 2,2-difluoropropane, 1,1,1- trifluoropropane, perfluoropropane, dichloropropane, difluoropropane, perfluorobutane, perfluorocyclobutane. Non-limiting examples of suitable partially halogenated chlorocarbons and chlorofluorocarbons include methyl chloride, methylene chloride, ethyl chloride, 1,1,1 -trichloroethane, 1,1-dichloro- 1-fluoroethane (HCFC-141b), 1-chloro- IJdifluoroethane (HCFC-142b), l,l-dichloro-2,2,2- trifluoro ethane (HCFC-123) and 1-chloro- l,2,2,2-tetrafluoroethane(HCFC-124). Non-limiting examples of suitable fully halogenated chlorofluorocarbons include trichloromonofluoromethane (OPOI 1}, dichlorodifluoromethane (CFO-12}, trichlorotrifluoroethane (CFO-113), 1,1,1- trifluoro ethane, pentafluoroethane, dichlorotetrafluoroethane (CFO-114), chloroheptafluoropropane, and dichlorohexafluoropropane. Non-limiting examples of suitable chemical blowing agents include azodicarbonamide, azodiisobutyro- nitrile, benezenesulfonhydrazide, 4,4-oxybenzene sulfonyl-semicarbazide, p-toluene sulfonyl semi-carbazide, barium azodicarboxylate, N,N'- dimethyl-N,N'- dinitrosoterephthalamide, and trihydrazino triazine.

[0083] Crosslinked Composition

[0084] The crosslinkable polymer compositions as described herein, including an ethylenebased polymer and at least one of BiPheS methacrylate and BiPheS extended methacrylate, may be melt blended at a temperature from 100 °C to 250 °C, from 120 °C to 200 °C, from 120 °C to 180 °C, or from 120 °C to 160 °C to trigger a crosslinking reaction and form the crosslinked composition.

[0085] In embodiments, the ethylene-based polymer of the crosslinked composition may form a polymer backbone and the at least one of the BiPheS methacrylate and the BiPheS extended methacrylate may be grafted onto the polymer backbone. The crosslinked composition may include disulfide linkages formed from the BiPheS methacrylate and / or the BiPheS extended methacrylate by way of the crosslinking reaction, the disulfide linkages formed from BiPheS methacrylate shown in Structure 3 below and the disulfide linkage formed from BiPheS extended methacrylate shown in Structure 4 below.

[0086] The term (and structure) “Pm” in Structures 3 and 4 above refers to the chain of polymerized ethylene (and optional comonomer(s)) for the ethylene based polymer.

[0087] The properties of the crosslinked composition may be evaluated at an elevated temperature greater than the melting temperature of the ethylene-based polymer (e.g., 160 °C). Properties of the crosslinked composition at the elevated temperature may be more indicative of crosslinking as the ethylene-based polymer will have already melted at theelevated temperature. Properties evaluated at a relatively lower temperature less than the melting temperature of the ethylene-based polymer (e.g., 60 C) may capture both the ethylene-based polymer and the crosslinking.

[0088] The crosslinked composition may provide a substantial network response upon crosslinking (e.g., E' at 160 °C greater than 0.1 MPa). In embodiments, the crosslinked composition may comprise E' at 160 °C greater than 0.1 MPa, greater than 0.2 MPa, greater than 0.3 MPa, greater than 0.4 MPa, or even greater than 0.5 MPa.

[0089] Damping ratio (tan 8) at 160 °C is similarly indicative of crosslinking, with a relatively larger presence of crosslinks corresponding to a relatively lower Tan 8 at 160 °C (e.g., less than 0.59). In embodiments, the crosslinked composition may comprise tan 8 at 160 °C less than 0.59, less than 0.55, less than 0.50, less than 0.45, or even less than 0.40.

[0090] In embodiments, the crosslinked composition may comprise E' at 60 °C greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, greater than 10, greater than 25, or even greater than 50.

[0091] While not wishing to be bound by theory, the desired tan 8 at 60 °C of a given crosslinked composition may be dependent on the properties of the ethylene-based polymer being used therein. In embodiments, the crosslinked composition may comprise tan 8 at 60 °C less than 0.25. In embodiments, the crosslinked composition may comprise tan 8 at 60 °C less than 0.13. In embodiments, the crosslinked composition may comprise tan 8 at 60 °C less than 0.25, less than 0.23, less than 0.20, less than 0.17, less than 0.15, less, than 0.13, or even less than 0.10.

[0092] In embodiments, the ethylene-based polymer may comprise a virgin ethylene-based polymer. “Virgin ethylene-based polymer,” as used herein, is an ethylene-based polymer that has not been subjected to crosslinking reaction. That is, “virgin ethylene-based polymer” refers to the ethylene-based polymer that is present in the crosslinkable polymer composition and the resulting crosslinked composition prior to the ethylene-based polymer being crosslinked with the BiPheS methacrylate and / or the BiPheS extended methacrylate. The virgin ethylene-based polymer is the ethylene-based polymer prior to crosslinking, the crosslinked composition containing the same ethylene-based polymer that was virgin, but is now crosslinked with the BiPheS methacrylate and / or the BiPheS extended methacrylate. Inthis way, the virgin ethylene-based polymer may serve as a baseline to evaluate properties of the crosslinked composition.

[0093] In embodiments, the crosslinked composition may comprise E' at 160 °C that is greater than the E' for the virgin ethylene-based polymer at 160 °C, due to the increased crosslinking. Similarly, in embodiments, the crosslinked composition may comprise tan 8 at 160 °C that is less than the tan 8 value of the virgin ethylene-based polymer at 160 °C.

[0094] In embodiments, the crosslinked composition may comprise E' at 60 °C that is about equal to the E' for the virgin ethylene-based polymer at 60 °C, due to the change in crystallinity after dynamic crosslinking and processing compared to the virgin polymers. E' at 60 °C of the crosslinked composition may be slightly smaller (decrease in crystallinity will decrease E' below the melt transition despite enhancement from crosslinking) or slightly larger (crystallinity is marginally affected and crosslinking enhances E') as compared to the virgin ethylene-based polymer. In embodiments, the crosslinked composition may comprise tan 8 at 60 °C that is less than the tan 8 value of the virgin ethylene-based polymer at 60 °C.

[0095] Reprocessability and / or Recyclability

[0096] The dynamic crosslinker BiPheS methacrylate or BiPheS extended methacrylate enables a cyclic “reprocessing” for fabrication of new polymeric articles or molds. BiPheS methacrylate and BiPheS extended methacrylate are mostly associative in nature and, thus, crosslinked compositions containing them retain their crosslinked nature at the reprocessing temperature. More specifically, when the crosslinked ethylene-based polymer composition is heated to the reprocessing temperature, a relatively small amount of the disulfide linkages break, or otherwise cleave, into sulfur radicals. The sulfur radicals interchange with stillexisting disulfide linkages to simultaneously “swap in” the radical to become a new partner and eject one of the old partners as a new radical. The new radical can then interact with other linkages for further bond exchange, enabling reprocessing. This may be referred to as a “[2+1] radical mediated mechanism.”

[0097] The cleaving and interchange that occurs at the reprocessing temperature enables the previously-crosslinked ethylene-based polymer composition to flow at the reprocessing temperature, forming a reprocessable ethylene-based composition. Heating to the reprocessing temperature enables link interchange and polymer chain flow, allowing the ethylene-based composition to be reshaped readily. At the reprocessing temperature, thereprocessable ethylene-based polymer composition is flowable, enabling shaping and / or fabrication of the now flowable re-processable ethylene-based composition (with BiPheS methacrylate and / or BiPheS extended methacrylate) into a new pre-form or article. Upon cooling to below the reprocessing temperature, the disulfide linkages essentially become static, the network is re-established, and the re-crosslinked ethylene-based composition is formed in the new article configuration with a return to the high viscosity (no flow at room temperature) and resistance to mechanical deformation indicative of the crosslinked network. When the newly-formed article of the reprocessable ethylene-based polymer composition is cooled below the reprocessing temperature, the disulfide linkages in the re-processable ethylene-based polymer composition are fully reestablished and the ethylene-based polymer (with BiPheS methacrylate and / or BiPheS extended methacrylate) becomes a recrosslinked ethylene-based polymer composition in the shape of the newly-fabricated article. Below the reprocessing temperature, the network disulfide linkages are stable, and the recrosslinked ethylene-based polymer composition exhibits the high viscosity and resistance to mechanical deformation indicative of a crosslinked network. This cycle of crosslink / reprocess / re- crosslink and fabrication into a new article can be repeated.

[0098] Bounded by no particular theory, the number of “reprocessing” cycles that are possible with the present crosslinked ethylene-based composition (before competitive thermal and oxidative permanent crosslinking occurs and prevents further reprocessing), can be determined by calculating the ratio of the melt viscosity of the crosslinked ethylene-based polymer composition before and after a reprocessing cycle. For the crosslinked ethylenebased polymer composition to be re-processable, the ratio of the Mooney viscosity after reprocessing to the Mooney viscosity before reprocessing is from 0.5 to 5, or from 0.7 to 3 or from 0.9 to 2 or from 0.95 to 1.2.

[0099] Other metrics for monitoring the number of “reprocessing” cycles that are possible with the BiPheS methacrylate and / or BiPheS extended methacrylate dynamic crosslinkers before competitive oxidative permanent crosslinking occurs include visual observation. Formed film that is mechanically deformed is heated to the reprocessing temperature and is visually inspected to determine whether the mechanically deformed film heals to form a stable film. This metric of re-processability is noted in Table 2 below.

[0100] In embodiments, a process may comprise heating a first article to a reprocessing temperature; forming, at the reprocessing temperature, the first article into a re-processableethylene-based polymer composition; shaping, at the reprocessing temperature, the reprocessable ethylene-based composition into a re-processed pre-form; cooling the reprocessed pre-form to below the reprocessing temperature; and forming a second article, the second article comprising a re-crosslinked composition. The second article may be different from the first article.

[0101] In embodiments, the reprocessing temperature may be from 100 °C to 250 °C, thereby breaking disulfide linkages of the cross-linked composition and forming the reprocessable ethylene-based polymer composition. In embodiments, the reprocessing temperature may be from 100 °C to 250 °C, from 100 °C to 225 °C, from 100 °C to 200 °C, from 100 °C to 175 °C, from 130 °C to 250 °C, from 130 °C to 225 °C, from 130 °C to 200 °C, from 130 °C to 175 °C, from 160 °C to 250 °C, from 160 °C to 225 °C, from 160 °C to 200 °C, from 160 °C to 175 °C, from 190 °C to 250 °C, from 190 °C to 225 °C, or even from 190 °C to 200 °C, from 100 °C to 175 °C, or any and all sub-ranges formed from any of these endpoints.

[0102] In embodiments, the shaping step is a procedure selected from the group consisting of injection molding, extrusion molding, thermoforming, slushmolding, over molding, insert molding, blow molding, cast molding, tentering, compression molding, and combinations thereof.

[0103] In embodiments, the crosslinked composition recovers its storage modulus after successive molding cycles (e.g., E' at 160 °C of 2ndmold greater than or about equal to E' at 160 °C of 1stmold) thereby providing a reprocessable and / or recyclable crosslinked ethylenebased polymer. The crosslinked composition of the second article and of successive articles may have the same or similar E' at 160 °C, tan 8 at 160 °C, E' at 60 °C, and / or tan 8 at 60 °C as described hereinabove with respect to the crosslinked composition.

[0104] Nonlimiting examples of suitable articles (first article and second article) for the present crosslinked / re-crosslinked ethylene-based polymer (with BiPheS methacrylate and or BiPheS extended methacrylate) composition include elastic film; elastic fiber; soft touch good, such as tooth brush handles and appliance handles; gaskets and profiles; adhesives (including hot melt adhesives and pressure sensitive adhesives); footwear (including shoe soles and shoe liners); auto interior parts and profiles; foam articles (both open cell foam and closed cell foam); impact modifiers for other thermoplastic polymers such as high densitypolyethylene, isotactic polypropylene, or other olefin polymers; coated fabrics; hoses; tubing; weather stripping; cap liners; flooring; and combinations thereof.

[0105] TEST METHODS

[0106] Density

[0107] Density was measured in accordance with ASTM D792 with results reported in g / cm3at 25 °C.

[0108] Melt Index (MI and I2)

[0109] MI (for ethylene based polymers) was measured in accordance with ASTM D 1238, Condition 190 °C / 2.16 kg with results reported in grams per 10 minutes (g / 10 min). I21 was measured in accordance with ASTM D 1238, Condition 190 °C / 21.6 kg with results reported in grams per 10 minutes (g / 10 min).

[0110] Dynamic Mechanical Analysis (DMA)

[0111] DMA experiments were conducted using a TA Instruments RSA-G2 Solid Analyzer to measure the storage modulus (E1), loss modulus (E"), and damping ratio (tan 8) of crosslink networks as a function of temperature and recycling under a nitrogen atmosphere. DMA was operated in tension mode at a frequency of 1 Hz with a 0.03% oscillatory strain. Data was collected from room temperature to 180 C with a heating rate of 3 °C / minute.

[0112] Differential Scanning Calorimetry (DSC)

[0113] DSC was conducted using a Mettler Toledo DSC822e differential scanning calorimeter to measure thermal properties including peak and endpoint melting temperatures and crystallinities of the virgin polymer and crosslinked compositions (network polymers). The network materials tested for most polymers are samples of the crosslinked lst-molded samples. A 10 °C / min heating rate and a 10 °C / min cooling rate were adapted for all measurements in a temperature range of 0 °C to 160 °C.

[0114] Rheology Analysis Using Rubber Process Analyzer (RPA)

[0115] Rheology of the compositions was measured using a rotorless oscillating shear rheometer, Alpha Technologies RPA 2000 instrument, according to ASTM D6204, under the following test conditions and exceptions. The sample was placed between two pieces of Mylar film for analysis. Rheology was monitored during an initial timed test at 180 °C, 1.0 rad / s, 7% strain, for 30 min. Elastic torque, S', at the end of the 30 min crosslinking step wasrecorded. Immediately following the 30 min at 180 °C, a frequency sweep from 0.1 to 100 rad / s was conducted at 180 °C, 7% strain on the same sample, followed by a frequency sweep from 0.1 to 100 rad / s at 230 °C, 7% strain. The dynamic viscosity, n*, and tan delta were recorded for each frequency sweep. In ASTM D6204, frequency sweeps on unvulcanized rubber were conducted prior to a cure step. In this case, frequency sweeps were conducted after in the initial crosslinked step at 180 °C to evaluate the reversibility of crosslinking.

[0116] EXAMPLES

[0117] By way of example, and not limitation, some embodiments of the present disclosure will not be described in detail by the following examples.

[0118] Materials

[0119] Materials used in Comparative Examples Cl -Cl 6 and Exemplary Examples El -El 2 are provided in Table 1 below.Table 1

[0120] Synthesis of BiPheS methacrylateTo synthesize BiPheS methacrylate, bis(4-hydroxyphenyl) disulfide (1.00 g, 3.99 mmol, supplied by Ambeed, Inc.) and triethylamine (1.62 g, 16.0 mmol, supplied by Sigma-Aldrich) were added to dry acetonitrile (20 mL, supplied by Fisher Scientific) in a round-bottom flask and stirred under nitrogen flow until dissolution. The solution was then cooled to 0 °C in an ice bath, at which point methacryloyl chloride (1.67 g, 16.0 mmol, supplied by Sigma- Aldrich) was added dropwise under vigorous stirring. The resulting mixture was warmed to 30 °C and allowed to react for 24 hours. After evaporating the solvent under reducedpressure, the precipitates were dissolved in chloroform, washed via liquid-liquid extraction with a 0.10 mol / L potassium carbonate solution (3 x 150 mL) and water (3 x 150 mL), and dried over magnesium sulfate. The organic layer was then filtered and evaporated under reduced pressure, resulting in a yellow-orange solid, which was recrystallized from ethanol to result in light-yellow crystals. The crystals were dried in a vacuum oven at 80 °C for 24 hours to yield BiPheS methacrylate, as shown in Structure 1 above.

[0121] Synthesis of BiPheS extended methacrylate

[0122] To synthesize BiPheS extended methacrylate, bis(4-hydroxyphenyl) disulfide (1.00 g, 3.99 mmol, supplied by Ambeed, Inc.) and dibutyltin dilaurate (0.05 mL, supplied by Sigma- Aldrich) were added to dry acetonitrile (20 mL, supplied by Fisher Scientific) in a round-bottom flask and stirred under nitrogen flow until dissolution. Following this, 2- isocyanatoethyl methacrylate (1.24 g, 7.99 mmol, supplied by TCI America) was added dropwise under vigorous stirring. The resulting mixture was allowed to react for 24 hours at room temperature. After evaporating the solvent under reduced pressure, the precipitates were dissolved in chloroform, washed via liquid-liquid extraction with water (6 x 150 mL), and dried over magnesium sulfate. The organic layer was then filtered and evaporated under reduced pressure, resulting in a light-yellow solid which is recrystallized from ethanol to result in off-white crystals. The crystals were dried in a vacuum oven at 80 °C for 24 hours to yield BiPheS extended methacrylate, as shown in Structure 2 above.

[0123] Preparation of crosslinked compositions

[0124] Appropriate masses of starting materials including polymer pellets (ethylene-based polymer), crosslinker (BiPheS methacrylate or BiPheS extended methacrylate), and radical initiator (dicumyl peroxide) were massed separately on an analytical balance (typically, 2 g of polymer, 0.1 g of crosslinker, and 0.02 g of radical initiator). Prior to synthesis, the cup of a Dynisco (formerly Atlas) Faboratory Mixing Molder (LMM) was flushed of impurities by loading the polymer of interest, heating to above its melt transition, and mixing for 3-5 minutes. After removing the polymer debris from flushing, the massed polymer pellets and the powder mixture of crosslinker and radical initiator were added via spatula into the cup. The starting materials were added in doses such that they were evenly distributed throughout the cup prior to mixing. Additionally, three steel balls (~5 mm diameter) were added evenly to the cup to emulate extrusion processes during melt-state mixing. Next, the temperature ofthe LMM was increased above the melt transition of the polymer, and the starting materials were mixed at this temperature at 120 RPM (maximum rotational speed) for 3-5 minutes to ensure homogenization of the ingredients in the melt state while minimizing radical initiation. For ELVAX 260 and ENGAGE 8100, this mixing temperature was 100 °C. For DOWLEX 2045G, INFUSE 9100, and LDPE 5044i, this mixing temperature was 130 °C. For DMDA 6200, this mixing temperature was 140 °C. During mixing, the rotor of the LMM was manually cycled upwards and downwards periodically to facilitate homogenization of the blend.

[0125] After mixing, the homogenized polymer blend was removed from the cup via spatula. The blend was then compression molded into a mm-thick film in a PHI press (Model 0230C- XI) at 180 °C (a temperature at which radical initiation and crosslinker grafting processes can commence) and 10 MPa for 30 minutes to obtain a crosslinked lst-molded sample. The film was then cut into mm-sized pieces and compression molded at 200 °C and 10 MPa for 1 hour to obtain a reprocessed 2nd-molded sample. Strips were cut from each sample film for dynamic mechanical analysis (DMA).

[0126] ENGAGE™ 8100

[0127] Referring now to Table 2, Comparative Compositions C1-C9 and Example Compositions E1-E7, crosslinkable compositions containing ENGAGE™ 8100 with varying amounts of BiPheS methacrylate (crosslinker), BiPheS extended methacrylate (crosslinker), and dicumyl peroxide (free radical initiator), were formed.

[0128] Referring now to Table 3, the performance criteria of the crosslinked compositions are shown. Processability of crosslinked compositions (network blends) were assessed by film quality after completing the aforementioned standard compression molding procedure and conditions shown in Table 2. Thermomechanical properties of the crosslinked compositions (network blends) were also tested via DMA to assess network response for 1st- molded samples compared to virgin ENGAGE™ 8100 material. Hence, performance criteria were based on the virgin ENGAGE™ 8100’s properties. As noted herein, the performance criteria of the crosslinked compositions, such as tan 8 at 60 °C, may be dependent on the properties of the ethylene-based polymer being used therein, such as ENGAGE™ 8100.Table 2* For processability:1 — Network blend is not processable; pieces do not heal to form cohesive film for property testing.2 — Network blend is partially processable; pieces heal partially and require more time to heal fully. Resulting films are intact to enable property testing.3 — Network blend is fully processable; pieces heal completely, allowing for exhaustive property testing and recycling.N / A — Sample was not tested due to lack of processability or network response.Table 2 cont.Table 2 cont.Table 3

[0129] In Table 2, a minimum E' at 160 °C of 0.1 MPa is indicative of a network response (crosslinking) over the thermoplastic response of virgin ENGAGE™ 8100 with crosslinkerand free radical initiator. Typically, synthesizing dynamic networks via the described procedures is successful for most polymers using 5 wt% crosslinker and 1 wt% free radical initiator. Table 2 shows (i) the amount of free radical initiator being varied while holding the BiPheS methacrylate amount constant at 5 wt%; and (ii) varying the amount of BiPheS methacrylate while holding the free radical initiator amount constant at 1 wt%. This two- prong approach enabled the assessment of the limits of achieving a network response (crosslinking) for a model polymer (in this case, ENGAGE 8100) while maintaining processability in a compression molder.

[0130] From Table 2, the viable ranges of BiPheS methacrylate and free radical initiator for ENGAGE™ 8100 were 4.5 wt% to 10 wt% and 0.4 wt% to 1 wt%, respectively. These ranges gave network responses (E' about 0.1 MPa at 160 °C) and enable partial or full processability assessed through film quality after compression molding. In Table 2, Example Compositions E1-E4 were fully processable (score of 3 for processability / film quality). Example Composition El (4.72 wt% BiPheS methacrylate (crosslinker) and 0.94 wt% dicumyl peroxide (radical initiator)) had an E' at 160 °C of 1.08 MPa, correlating to the strongest dynamic network response. Comparative Compositions C1-C8 in Table 2 either did not produce network material due to insufficient crosslinker or radical initiator (Comparative Compositions Cl and C8) or were unable to be processed after compression molding due to overloading of radical initiator, forming permanent crosslinks incapable of dynamic chemistry (Comparative Compositions C2-C7). Thus, ENGAGE™ 8100 materials synthesized from C1-C8 either flowed above the melt transition or could not produce healed films, both of which prevented characterization via DMA.

[0131] Table 2 also contains Comparative Composition C8 and Example Composition E5 made with BiPheS extended methacrylate. Synthesis of a dynamic network using 5 wt% BiPheS extended methacrylate and 1 wt% free radical initiator resulted in Comparative Example C8, which was only partially processable due to the presence of permanent crosslinks. Reduction of radical initiator loading to 0.71 wt% resulted in a fully processable formulation, Example Composition E5, with a strong dynamic network response exceeding 0.1 MPa at 160 °C.

[0132] Polymer Evaluation

[0133] Based on the findings of ENGAGE™ 8100, the El formulation for ENGAGE™ 8100 (2 g polymer basis, 5 wt% crosslinker, 1 wt% radical initiator) was translated to DMDA 6200, DOWLEX™ 2045G, ELVAX™ 260, INFUSE™ 9100, and LDPE 5004i. Example Compositions El and E5-E10 are shown in Table 4. Relative to the ENGAGE™ 8100 examples, ELVAX™ 260 (Example Composition E8) required an additional amount of radical initiator (i.e., 1.87 wt%) and LDPE 5004i (Example Composition E10) required a lower amount of BiPheS methacrylate (i.e., 3.62 wt%) to achieve similar dynamic network response and reprocessing results.

[0134] Regarding ELVAX™ 260, while not wishing to be bound by theory, it is believed that the molecular weight and / or viscosity of ELVAX™ 260 relative to ENGAGE™ 8100 and other polymers resulted in a greater amount of radical initiator being needed in Example Composition E8 to produce desirable results. Indeed, Comparative Example C6, including ENGAGE™ 8100 and 1.87 wt% dicumyl peroxide, did not produce desirable results. While also not wishing to be bound by theory, as ELVAX™ 260 is “softer” than ENGAGE™ 8100, some degree of permanent crosslinks being introduced by a relatively higher free radical initiator content helped to retain the cohesiveness of the ELVAX™ 260 network as dynamic BiPheS methacrylate crosslinks enable reprocessing. While also not wishing to be bound by theory, ELVAX™ 260 contains a relatively high fraction of vinyl acetate repeat units that are less amenable to grafting than olefin comonomers such as 1 -octene used in ENGAGE™ 8100, leading to the need for a relatively greater amount of free radical initiator.

[0135] Regarding LDPE 5004i, while not wishing to be bound by theory, it is believed that the amount of units amenable to grafting in LDPE 5004i relative to ENGAGE™ 8100 resulted in relatively less reversible crosslinker being needed in Example Composition E10 to produce desirable results. Indeed, Comparative Composition E4, including ENGAGE™ 8100 and 3.81 wt% BiPheS methacrylate did not produce desirable results.

[0136] Sufficient network responses and full recoveries of thermomechanical properties evaluated using DMA after 2 successive compression molding cycles were obtained with this formulation for each of the ethylene-based polymers. The performance criteria of the crosslinked compositions are shown in Table 5. “Virgin” or “virgin polymer,” as used in this Polymer Evaluation example, refers to ENGAGE™ 8100, DMDA 6200, DOWLEX™ 2045G, ELVAX™ 260, INFUSE™ 9100, LDPE 5004i prior to crosslinking.

[0137] Comparative Compositions C10-C16 in Table 6 include formulations that did not produce reprocessable network materials, as well as virgin polymer formulations without any crosslinker or radical initiator.Table 4Table 4 cont.Table 5Table 6Table 6 cont.

[0138] Table 4 exhibits E' and tan 8 at 60 °C and 160 °C for Example Compositions El and E5-E10.

[0139] E' at 60 °C of the network polymers were about equal (on the same order of magnitude) to the E' at 60 °C of the respective virgin polymers with experimental uncertainty. Depending on the change in crystallinity after dynamic crosslinking and processing compared to the virgin polymers, E' at 60 °C was slightly smaller (decrease in crystallinity will decrease E' below the melt transition despite enhancement from crosslinking) or slightly larger (crystallinity is marginally affected and crosslinking enhances E'). Successive molds at 60 °C for each of the polymer formulations exhibited E' at 60 °C approximately equal (on the same order of magnitude) to the E' at 60 °C of the respective virgin polymers and lst-molded samples within experimental uncertainty.

[0140] At 160 °C, E' of the network polymers of Example Compositions El and E5-E10 were substantially larger than the E' at 160 °C of the respective virgin polymers, as the virgin polymers did not possess network characteristics that would give relatively large E' at 160 °C (e.g., > 0.1 MPa) above the melt transitions. Successive molds at 160 °C for each of the Example Compositions El and E5-E10 exhibited E' at 160 °C approximately equal (on the same order of magnitude) or slightly larger (from additional crosslink formation during processing) to the E' at 160 °C of the lst-molded samples within experimental uncertainty.

[0141] Coinciding with the larger presence of crosslinks in the network materials, tan 8 at 60 °C and 160 °C were smaller for the Example Compositions El and E5-E10 compared to their virgin counterparts. Additionally, these values were maintained for successivelymolded samples at both temperatures. The Example Compositions El and E5-E10 demonstrate that the polymers not only give substantial dynamic network responses upon crosslinking (>1 MPa at 60 °C and > 0.1 MPa at 160 °C), but are also reprocessable and recover their E' and tan 8 after successive compression molding cycles. Comparative examples that were processable did not achieve substantial network responses, and comparative examples that gave substantial network responses were unable to be processed and do not recover thermomechanical properties after processing.

[0142] Table 4 also provides the thermal properties (melting ranges and crystallinities) of the virgin polymers and Example Compositions El and E5-E10 (network formulations) determined by DSC. Reactive crosslinking diminished the order of the crystal structures forming during cooling post-process, which decreased the crystallinities as well as melting peaks and endpoints of the network polymers compared to their virgin counterparts.

[0143] Rheology Analysis

[0144] Ethylene-based polymer (ENGAGE™ 8100), BiPheS methacrylate, and free radical initiator (dicumyl peroxide), were combined in the amounts shown in Table 7 and batch mixed at 100 °C to form crosslinkable polymer compositions. The crosslinkable polymer compositions were heated on an RPA at 180 °C for 30 minutes to initiate the crosslinking reaction. Properties of the crosslinked composition Example Compositions El l and E12 are provided in Table 7 below.Table 7

[0145] In Table 7, the RPA results are summarized and indicate whether a material was crosslinked based on RPA S' value, and whether the crosslinked compositions were reprocessable based on VRR (i.e., viscosity ratio, VRR = RPA n*(0.1) at 180 °C / RPA n*(0.1) at 230 °C). The S' at 180°C, 30 min and n* at 0.1 rad / s, 180°C indicate the formulation underwent a crosslinking reaction.

[0146] A high RPA S' indicates that the composition during initial curing step can reach a crosslinked state.

[0147] Generally, a high VRR (greater than 5) is needed to reprocess the crosslinked materials during extrusion, or otherwise be reprocessable. However, for Example Compositions El l and El 2, a high VRR (greater than 5) was not observed. Despite that, the examples were reprocessable and could be remolded. While not wishing to be bound by theory, it is believed that Example Compositions El l and El 2, including BiPheS methacrylate, do not decrosslink at the RPA measurement temperature of 230 °C, likely due to the associative nature of BiPheS methacrylate, which causes the crosslinked composition to retain its crosslinked nature at elevated temperatures. 230 °C is the upper limit of the measurement capability for the RPA instrument. Therefore, VRR values for Example Compositions El 1 and E12 remained low around 1.4. It would be expected that if the RPA viscosity measurement was carried out at higher temperature, the VRR for Example Compositions El l and E12 would be high and greater than 5.

[0148] Additionally, Example Compositions El 1 and E12 were colorless in appearance after curing and their viscosity reduced at temperatures higher than the melting temperature of BiPheS methacrylate. These additional features may enable a broader melt reprocessing window to further lower the composition viscosity and reprocess, reshape, or remold the composition into a new article using conventional polymer processing equipment. While not wishing to be bound by theory, it is believed that the colorless appearance of Example Compositions El l and E12 was because the BiPheS methacrylate became crosslinked, thereby inhibiting composition while incorporating itself into the crosslinked structure, andresulting in a clear appearance. The BiPheS methacrylate may not have been completely miscible with ENGAGE™ 8100.

[0149] While particular embodiments of the present disclosure have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the disclosure. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this disclosure.

Claims

CLAIMS1. A crosslinked composition comprising: an ethylene-based polymer; and at least one of bis(4-methacryloyloxyphenyl) disulfide (BiPheS methacrylate) and bis(4- methacryloyloxy ethylcarbamoyloxyphenyl) disulfide (BiPheS extended methacrylate).

2. The crosslinked composition of claim 1, wherein the ethylene-based polymer forms a polymer backbone and the at least one of the BiPheS methacrylate and the BiPheS extended methacrylate is grafted onto the polymer backbone.

3. The crosslinked composition of claim 1, wherein the crosslinked composition comprises linkages of Structure 3 or Structure 4:

4. The crosslinked composition of any one of claims 1-3, comprising: from 70 wt% to 96.5 wt% of the ethylene-based polymer, the ethylene-based polymer having a melt index from 0.1 g / 10 min to 100 g / 10 min; andfrom 3.5 wt% to 20 wt% of the at least one of BiPheS methacrylate and BiPheS extended methacrylate.

5. The crosslinked composition of any one of claims 1-4, wherein the ethylene-based polymer is selected from the group consisting of ethylene plastomer / elastomer, high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ethylene / a-olefm multi-block copolymer, and combinations thereof.

6. The crosslinked composition of any one of claims 1-4, wherein the ethylene-based polymer is a polar ethylene-based polymer, the polar ethylene-based polymer comprising ethylene / vinyl acetate copolymer (EVA).

7. fhe crosslinked composition of any one of claims 1-6, wherein the crosslinked composition has: a storage modulus (E') at 160 °C greater than or equal to 0.1 MPa; and a damping ratio (tan 8) at 160 °C less than 0.59.

8. The crosslinked composition of any one of claims 1-7, wherein: the ethylene-based polymer is a virgin ethylene-based polymer prior to the crosslinked composition being crosslinked; and the crosslinked composition has:E' at 160 °C that is greater than the E' for the virgin ethylene-based polymer at 160 °C; and tan 8 at 160 °C that is less than the tan 8 value of the virgin ethylene -based polymer at 160 °C.

9. A process comprising: heating a first article to a reprocessing temperature, the first article comprising a crosslinked composition, wherein the crosslinked composition comprises: an ethylene-based polymer; and at least one of bis(4-methacryloyloxyphenyl) disulfide (BiPheS methacrylate) and bis(4-methacryloyloxy ethylcarbamoyloxyphenyl) disulfide (BiPheS extended methacrylate);forming, at the reprocessing temperature, the first article into a re-processable ethylenebased polymer composition; shaping, at the reprocessing temperature, the re-processable ethylene -based composition into a re-processed pre-form; cooling the re-processed pre-form to below the reprocessing temperature; and forming a second article, the second article comprising a re-crosslinked composition, wherein the re-crosslinked composition comprises: the ethylene-based polymer; and the at least one of BiPheS methacrylate and BiPheS extended methacrylate; wherein the second article is different from the first article.

10. The process of claim 9, wherein the reprocessing temperature is from 100 °C to 250 °C, thereby breaking disulfide linkages of the cross-linked composition and forming the reprocessable ethylene-based polymer composition.

11. The process of claim 9 or claim 10, wherein the crosslinked composition comprises linkages of Structure 3 or Structure 4:

12. The process of any one of claims 9-11, wherein the crosslinked composition comprises: from 70 wt% to 96.5 wt% of the ethylene-based polymer, the ethylene-based polymer having a melt index from 0.1 g / 10 min to 100 g / 10 min; and from 3.5 wt% to 20 wt% of the at least one of BiPheS methacrylate and BiPheS extended methacrylate.

13. The process of any one of claims 9-12, wherein the ethylene -based polymer is selected from the group consisting of ethylene plastomer / elastomer, high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ethylene / a-olefin multi-block copolymer, and combinations thereof.

14. The process of any one of claims 9-12, wherein the ethylene-based polymer is a polar ethylene-based polymer, the polar ethylene -based polymer comprising ethylene / vinyl acetate copolymer (EVA).

15. The process of any one of claims 9-14, wherein the second article comprises: a storage modulus (E') at 160 °C greater than or equal to 0.1 MPa; andE' at 160 °C of the second article is greater than or about equal to E' at 160 °C of the first article.

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