Graft copolymer for compatibilization of polyethylene and polypropylene

Abstract

Graft copolymers, methods for making the graft copolymers, polymer blends made from the graft copolymers, methods for making the polymer blends, and articles made from the graft copolymers and their blends are provided. The graft copolymers can be made from ethylene and isotactic polypropylene. The polymer blends can be made from semi-crystalline polyethylene, polypropylene, and the graft copolymers of the present invention.

Description

Cross - Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No. 62 / 900,097, filed on September 13, 2019, the disclosure of which is incorporated herein by reference. Statement regarding Federally Sponsored Research

[0002] This invention was made with government support under Contract No. 1413862 and 1901635 awarded by the National Science Foundation. The government has certain rights in this invention. Background of the Invention

[0003] Plastics are an integral part of modern society, and the production of industrial polymers has increased dramatically since 1970. Unfortunately, most plastics are disposed of in landfills or the environment. This is a concern regarding polyethylene (PE) and isotactic polypropylene (iPP), which account for two - thirds of all polymers manufactured worldwide and are commonly used in single - use applications such as packaging. Currently, about 1% of iPP and less than 7% of PE are recycled. The low recycling rate is largely due to the recycling challenges presented by mixed polyolefin - based waste streams. High - density polyethylene (HDPE) and iPP are generally found together in mixed plastic waste and are difficult to separate using optical or density - separation techniques. Melt - processing HDPE and iPP waste into a mixture product is one potentially useful way to avoid the need for waste - stream separation. However, mixtures of HDPE and iPP are often brittle and have poor mechanical properties due to phase separation of the two polymers.

[0004] Most industrially produced HDPE and iPP are manufactured using heterogeneous catalysts. Previous studies have shown that HDPE and iPP prepared using heterogeneous catalysts contain a significant amount of amorphous non-crystalline material that rapidly migrates to the interface, tangles, inhibits eutectic crystallization, and adhesion. Therefore, the ability to overcome the interfacial activity of amorphous chains is very important. The addition of non-reactive compatibilizers to HDPE and iPP mixtures is one way to improve their mechanical properties and represents a potential route for the utilization of mixed waste recycling streams. Current strategies for the non-reactive compatibilization of HDPE and iPP rely on the use of relatively large amounts (>10 wt%) of amorphous copolymer additives. Some of these copolymers are usually miscible with HDPE and iPP and produce some compatibilization activity, but the use of such large addition amounts results in plasticization that degrades the physical properties of the mixture. Block copolymers have found use in the compatibilization of other types of polymers and offer an attractive route for the compatibilization of HDPE and iPP.

[0005] The use of olefin block copolymers (OBCs) as compatibilizers and adhesives has been reported. The tensile properties of iPP-HDPE mixtures were improved by the addition of 10 wt% of a PE-poly(ethylene-co-octene) (PE-EO) OBC, which was due to the enhanced adhesion between the HDPE and iPP domains. A PE-iPP diblock copolymer (INTUNE TM commercially available as) was also tested as a compatibilizer and bonding layer for PE and iPP. Similar to the case of the PE-EO OBC, compatibilization of the iPP-HDPE mixture was observed at relatively high filler levels (5-10 wt%). However, due to the nature of the chain shuttling chemistry used to produce OBCs, they are composed of various block lengths and the number of blocks per chain.

[0006] The addition of linear PE-b-iPP multi-block copolymers to PE and iPP mixtures has been reported to significantly improve the tensile properties at low addition levels (Figure 1a). The clear nature of the multi-block additives and the controlled synthesis method enable the systematic study of the effects of the number and size of the blocks on the effectiveness of compatibilization.

[0007] Previous studies on polyolefin-based thermoplastic elastomers have shown that the physical properties of well-defined graft copolymers, characterized by semi-crystalline side chains and amorphous main chains, enhance the physical properties of linear block copolymers and can be prepared using non-living polymerization. This graft copolymer elastomer was produced using a "grafting through" strategy by copolymerizing allyl-terminated iso- or syndiotactic polypropylene macromonomers using a mixture of ethylene and octene or propylene.

[0008] A graft copolymer (GCP) containing a semi-crystalline PE backbone and iPP side chains (PE-g-iPP) was previously prepared via a "grafting to" method by reacting hydroxyl-terminated iPP with maleated PE. However, the presence of a significant amount of difunctionalized iPP results in the formation of a mixture of polymer structures. In addition, it has also been reported that a comb block copolymer containing a PE main chain and an atactic polypropylene graft can compatibilize HDPE and iPP. However, these materials were produced in a continuous reactor and the graft structure was not fully characterized. Summary of the Invention

[0009] The present invention provides a polymer (e.g., a copolymer such as a graft copolymer). A mixture of polymers (e.g., a polymer mixture) is also provided. A method for producing the polymer and a method for producing the polymer mixture are also provided.

[0010] In one aspect, the present invention provides a polymer. The polymer may be a graft copolymer. The graft copolymer may be a graft copolymer of polyethylene (PE) and isotactic polypropylene (iPP).

[0011] In one aspect, the present invention provides a polymer mixture (e.g., a graft copolymer mixture). The polymer mixture may be a mixture of the graft copolymer of the present invention and one or more semi-crystalline polyethylenes, a mixture of the graft copolymer of the present invention and one or more iPPs, or a mixture of the graft copolymer of the present invention and one or more semi-crystalline polyethylenes and one or more iPPs.

[0012] In one aspect, the graft copolymer is produced by the method of the present invention. The method of the present invention can include the polymerization of iPP and ethylene.

[0013] In one aspect, the present invention provides a method for producing a polymer mixture (e.g., a graft copolymer mixture). The graft copolymer mixture can be produced by melt-mixing the graft copolymer of the present invention with semi-crystalline polyethylene, or the graft copolymer of the present invention with iPP, or the graft copolymer of the present invention with iPP and semi-crystalline polyethylene.

[0014] In one aspect, the present invention provides a product. The product (e.g., an article) includes the graft copolymer of the present invention or the polymer mixture of the present invention (e.g., a graft copolymer mixture).

Brief Description of the Drawings

[0015] To more fully understand the essence and purpose of the present invention, reference should be made to the following detailed description with reference to the accompanying drawings.

[0016] Figure 1 shows additives for compatibilization of iPP / HDPE blends. (a) Well-defined PE-b-iPP multiblock copolymer, and (b) PE-g-iPP graft copolymer (c) Variations in the structure of PE-g-iPP graft copolymer.

[0017] Figure 2 shows TEM images and iPP average droplet sizes of iPP / HDPE 30 / 70 blends that (a) do not contain a compatibilizer, (b) contain 5 wt% of 398 PE 15 -g- 9.3 iPP 26 compatibilizer. (c) 5 wt% (orange, cooling rate of 10 °C / min) and 1 wt% (cooling rates of 10 °C / min and 23 °C / min) of 398 PE 15 -g- 9.3 iPP 26 Effect of number / chain of grafts on droplet size for the compatibilizer. Error bars are 95% confidence intervals.

[0018] Figure 3 shows typical uniaxial tensile elongation experiments for (a) pure HDPE, iPP, and PE-g-iPP copolymers of various graft sizes, and 30 / 70 iPP / HDPE blends (5 wt% of GCP cooled at 10 °C / min). (b) (c) Representative AFM images of stretched tensile test samples mixed with GCPs of various graft sizes, with ellipses added for visualization of elongated droplets. See Figure 15 for raw data.

[0019] Figure 4 shows the average strain at break for 30 / 70 iPP / HDPE blends containing 5 wt% PE-g-iPP copolymer cooled at 10 °C / min. For each blend, at least 5 tensile measurements were performed. Graft copolymers containing 26k and 28k grafts are shown in the same series. See Table 1 for standard deviations.

[0020] Figure 5 shows representative uniaxial tensile elongation experiments of pure HDPE and iPP, and mixtures of 30 / 70 iPP / HDPE with PE-g-iPP copolymers of various graft sizes containing (a) 1 wt% GCP cooled at 10 °C / min and (b) 1 wt% GCP cooled at 23 °C / min.

[0021] Figure 6 shows a general synthetic scheme for the synthesis of PE-g-iPP copolymers.

[0022] Figure 7 shows (A) area vs GPC sample mass plots for 6k-iPP macromonomer (Table 2, entry 2). (B) Area vs GPC sample mass plots for 14k-iPP macromonomer (Table 2, entry 3). (C) Area vs GPC sample mass plots for 14k-iPP macromonomer (Table 2, entry 4). (D) Area vs GPC sample mass plots for 26k-iPP macromonomer (Table 2, entry 5). (E) Area vs GPC sample mass plots for 28k-iPP macromonomer (Table 2, entry 6).

[0023] Figure 8 shows graft copolymer mixtures (A) 185 PE 5.2 -g- 16 iPP 6 , (B) 221 PE 15 -g- 10 iPP 6 , (C) 63 PE 5.5 -g- 5.0 iPP 6 (D) 164 PE 13 -g- 5.5 iPP 14 , (E) 210 PE 8.9 -g -8.8 iPP 14 , (F) 260 PE 8.8 -g- 11 iPP 14 , (G) 212 PE 57 -g- 2.2 iPP14 、(H) 364 PE 74 -g- 2.9 iPP 26 、(I) 298 PE 30 -g- 4.6 iPP 28 、(J ) 398 PE 15 -g- 9.3 iPP 26 、(K) 413 PE39-g- 5.6 iPP 28 、(L) 320 PE 9.8 -g- 8.2 iPP 28 shows the experimental GPC traces and approximate GPC curves for

[0024] Figure 9 shows the DSC curves of the graft copolymer at a heating / cooling rate of 10 K / min for (A) the first cooling cycle and (B) the second heating cycle.

[0025] Figure 10 shows (a, b) the original mixture of iPP / HDPE 30 / 70 without compatibilizer, and 5 wt% of (c, d) 185 PE 5.2 -g- 16 iPP 6 、(e、f) 260 PE 8.8 -g- 11 iPP 14 、または(g、h) 398 PE 15 -g- 9.3 iPP 26 and shows the representative TEM micrographs and corresponding droplet size distributions for the iPP HDPE 30 / 70 mixture containing

[0026] Figure 11 shows 5 wt% of (a, b) 213 PE 57 -g- 2.2 iPP 14 、(c、d) 164 PE 13 -g- 5.5 iPP 14 、(e、f)210 PE 8.9 -g- 8.8 iPP 14 or (g, h) 260 PE 8.8 -g- 11 iPP 14 Shows representative TEM micrographs and the corresponding droplet size distributions of an iPP / HDPE 30 / 70 blend containing. All samples were cooled at 10 °C / min.

[0027] Figure 12 shows (a, b) representative AFM images and the corresponding droplet size distributions of a 1 wt% 398 PE 15 -g- 9.3 iPP 26 iPP / HDPE 30 / 70 blend with cooled at 23 °C / min (rapid cooling), or (c, d) cooled at 10 °C / min (slow cooling).

[0028] Figure 13 shows the effect of the average number of grafts / chains on the droplet size for an iPP / HDPE 30 / 70 blend with 5 wt% GCP cooled at 10 °C / min. Error bars are 95% confidence intervals.

[0029] Figure 14 shows (A) 5 wt% of 185 PE 5.2 -g- 16 iPP 6 , (B) 5 wt% of 221 PE 15 -g- 10 iPP 6 , (C) 5 wt% of 164 PE 13 -g- 5.5 iPP 14 , (D) 5 wt% of 210 PE 8.9 -g- 8.8 iPP 14 , (E) 5 wt% of 260 PE 8.8 -g- 11 iPP 14 , (F) 5 wt% of 213 PE 57 -g- 2.2 iPP 14, (G) 5 wt% of 364 PE 74 -g- 2.9 iPP 26 , (H) 5 wt% of 298 PE 30 -g- 4.6 iPP 28 , (I) 5 wt% of 398 PE 15 -g- 9.3 iPP 26 , (J) 5 wt% of 413 PE 39 -g- 5.6 iPP 28 , (j1) 5 wt% of PE-g-iPP cooled at a rate of 23 °C / min 413 PE 39 -g- 5.6 iPP 28 , (K) 5 wt% of 320 PE 9.8 -g- 8.2 iPP 28 , (L) 1 wt% of 185 PE 5.2 -g- 16 iPP 6 , (M) 0.5 wt% of 185 PE 5.2 -g- 16 iPP 6 , (N) 1 wt% of PE-g-iPP cooled at a rate of 23 °C / min 185 PE 5.2 -g- 16 iPP 6 , (O) 0.5 wt% of PE-g-iPP cooled at a rate of 23 °C / min 185 PE 5.2 -g- 16 iPP 6 , (P) 1 wt% of 260 PE 8.8 -g- 11 iPP 14 , (Q) 0.5 wt% of 260 PE 8.8 -g- 11 iPP 14 , (R) 1 wt% of PE-g-iPP cooled at a rate of 23 °C / min 260 PE 8.8 -g- 11 iPP 14 , (S) 0.5 wt% of PE-g-iPP cooled at a rate of 23 °C / min 260PE 8.8 -g- 11 iPP 14 、 (T) 1 wt% of 398 PE 15 -g- 9.3 iPP 26 、 (U) 0.5 wt% of 398 PE 15 -g- 9.3 iPP 26 、 (V) 1 wt% of PE - g - iPP cooled at a rate of 23 °C / min 398 PE 15 -g- 9.3 iPP 26 、 (X) 0.5 wt% of PE - g - iPP cooled at a rate of 23 °C / min 398 PE 15 -g- 9.3 iPP 26 、 (Y) It shows the uniaxial elongation of a 30 / 70 iPP / HDPE mixture with 5 wt% of 6k iPP macromonomer. (Z) 30 / 70 iPP / HDPE, (A1) HDPE, (B1) iPP, (C1) HDPE cooled at a rate of 23 °C / min, (D1) iPP cooled at a rate of 23 °C / min, (E1) Uniaxial elongation of 30 / 70 iPP / HDPE cooled at a rate of 23 °C / min.

[0030] Figure 15 shows an AFM image of an elongated tensile test sample made of 30 / 70 iPP / HDPE containing 5 wt% GCP. (a)(c) Raw images, (b)(d) The same images as in Figure 3(b)(c), with ellipses added for visualization of elongated droplets. Detailed Description of the Invention

[0031] The subject matter recited in the claims is illustrated by specific examples, but other examples including those that do not provide all of the advantages and features described herein are also within the scope of the invention. Various structural, logical, and process step changes can be made without departing from the scope of the invention.

[0032] Here, ranges of values are disclosed. These ranges set a lower limit value and an upper limit value. Unless otherwise specified, a range includes the lower limit value, the upper limit value, and all values between the lower limit value and the upper limit value, including all values up to the magnitude of the minimum value of the range (either the lower limit value or the upper limit value), but is not limited thereto.

[0033] As used herein, unless otherwise specified, the term "group" means monovalent (i.e., having one terminus capable of covalent bonding to other chemical species), divalent, or polyvalent (i.e., having two or more termini capable of covalent bonding to other chemical species). The term "group" also includes radicals (e.g., monovalent and polyvalent, e.g., divalent groups, trivalent groups, etc.). Exemplary examples of groups include the following:

Chemical formula

[0034] As used herein, the term "aliphatic group" means, unless otherwise specified, a branched or unbranched hydrocarbon group optionally including one or more degrees of unsaturation. Degrees of unsaturation include, but are not limited to, alkenyl groups, alkynyl groups, and aliphatic cyclic groups. Aliphatic groups include all integers of carbon numbers and ranges of carbon numbers therebetween, C 1 -C 20 aliphatic groups (e.g., C 1 、C 2 、C 3 、C 4 、C 5 、C 6 、C 7 、C 8 、C 9 、C 10 、C 11 、C 12 、C 13 、C 14 、C 15 、C 16 、C 17 、C 18 、C 19 、C 20) may also be used. The aliphatic group may be unsubstituted or substituted with one or more substituents. Examples of the substituent include halogen (-F, -Cl, -Br, -I), aliphatic group (e.g., alkyl group, alkenyl group, alkynyl group, etc.), halogenated aliphatic group (e.g., trifluoromethyl group, etc.), aryl group, halogenated aryl group, alkoxide group, amine group, nitro group, carboxylate group, carboxylic acid, ether group, alcohol group, alkyne group (e.g., ethynyl group, etc.), and combinations thereof, but are not limited thereto. The aliphatic group may be an alkyl group, alkenyl group, alkynyl group, carbocyclic group, etc.

[0035] As used herein, unless otherwise specified, the term "alkyl group" means a branched or unbranched saturated hydrocarbon group. Examples of the alkyl group include, but are not limited to, methyl group, ethyl group, propyl group, butyl group, isopropyl group, tert-butyl group, etc. For example, the alkyl group is C 1 -C 20 and includes all integer carbon numbers and the range of carbon numbers therebetween (e.g., C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 7 , C 8 , C 9 , C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 , C 20) and includes. This alkyl group may be unsubstituted or may be substituted with one or more substituents. Examples of substituents include, but are not limited to, for example, halogen (-F, -Cl, -Br, -I), aliphatic groups (e.g., alkyl groups, alkenyl groups, alkynyl groups, etc.), aryl groups, alkoxide groups, carboxylate groups, carboxylic acids, ether groups, amine groups, etc. and combinations thereof.

[0036] The present invention provides a polymer (e.g., a copolymer such as a graft copolymer). Also provided is a mixture of said polymers (e.g., a polymer mixture). Also provided is a method for producing said polymer and for producing said polymer mixture.

[0037] In one aspect, the present invention provides a polymer. This polymer may be a graft copolymer. The graft copolymer may be a graft copolymer of polyethylene (PE) and isotactic polypropylene (iPP).

[0038] The graft copolymer can include a semi-crystalline polyethylene (PE) segment and a plurality of semi-crystalline isotactic polypropylene (iPP) segments. Each iPP segment is covalently bonded to the PE segment. The iPP segment is a pendant group. The graft copolymer can be described by the following formula. w PE x -g- y iPP z , where w is the overall molecular weight (kDa), x is the average graft spacing (kDa), z is the graft size (kDa), and y is the average number of grafts.

[0039] The graft copolymer may have various molecular weights. The graft copolymer can have a number average molecular weight of 25 to 1000 kDa and can include all 0.1 Da values and the ranges between them (e.g., 50 to 500 kDa).

[0040] The PE segments of the graft copolymer can have various sizes (e.g., length (e.g., number of repeating units) and weight). The portion of the PE segment between each iPP segment may have a number average molecular weight (Mn) of 1 to 100 kDa, including all 0.1 Da values and the ranges therebetween. Each portion of the PE segment may have the same length (e.g., number of repeating units) and weight, or may have different lengths (e.g., number of repeating units) and weights. For example, one or more portions of the PE segment have the same length and weight, and one or more portions of the PE segment have different lengths and weights. In various examples, the PE segment refers to an alkyl backbone formed by copolymerization of an iPP macromonomer and PE. For example, the PE segment has the following structure.

Chemical formula

[0041] The graft copolymer may contain various numbers of iPP segments. The graft copolymer may have an average of 1 to 50 iPP segments, and these segments include all (0.1) values and ranges therebetween. Each iPP segment may have the same or different number average molecular weight (Mn). The iPP segment may have an Mn of 1 to 50 kDa, including all 0.1 Da values and the ranges therebetween. For example, one or more iPP segments have the same length and weight, and one or more iPP segments have different lengths and weights. In various embodiments, the iPP segment can have stereochemical or positional isomeric errors.

[0042] The graft copolymer may have the following structure.

Chemical formula

[0043] In various examples, the graft copolymer can include semi-crystalline iPP segments and a plurality of PE segments. Each PE segment is covalently bonded to the iPP segment. The PE segment is a pendant group. This graft copolymer is represented by the following formula. w PE x -g- y iPP z , Here, w is the overall molecular weight (kDa), x is the average graft spacing (kDa), z is the graft size (kDa), and y is the average number of grafts.

[0044] The iPP segments of the graft copolymer may have various sizes (e.g., length (e.g., number of repeating units)). The portion of the iPP segment between each PE segment may be from 1 to 100 kDa, including all 0.1 Da values and the ranges therebetween (e.g., 1 to 50 kDa). Each portion of the iPP segment may have the same length (e.g., number of repeating units) and weight, or may have different lengths (e.g., number of repeating units) and weights. For example, one or more portions of the iPP segment may have the same length and weight, and one or more portions of the iPP segment may have different lengths and weights. In various embodiments, the iPP segment can have stereochemical or positional isomeric errors.

[0045] The graft copolymer can contain various numbers of PE segments. The graft copolymer may have an average of 1 to 50 PE segments, including all values and ranges of 0.1 therebetween. Each PE segment may have the same or different number average molecular weights (Mn). The PE segments can have an Mn of 1 - 100 kDa, including all values and ranges of 0.1 therebetween (e.g., 1 - 50 kDa). For example, one or more PE segments have the same length and weight, and one or more PE segments have different lengths and weights.

[0046] The graft copolymer may have the following structure.

Chemical formula

[0047] The graft copolymer of the present invention may have various end groups. The end groups may be aliphatic groups (e.g., alkenyl groups, alkyl groups, etc.). For example, the end groups may be methyl groups or methylene groups, or groups generated from the monomers of the polymerization reaction (e.g., groups generated from ethylene groups and / or propylene groups). For example, the end groups may be unsaturated by a catalyst termination mechanism (e.g., alkenes). The end groups on the graft copolymer may be the same or different.

[0048] In various examples, the segment may further include one or more additional groups (e.g., contaminants). Examples of additional groups (e.g., contaminants sometimes referred to as “contaminant groups”) include, for PE segments, one or more polypropylene groups and / or one or more comonomer groups. For example, an iPP segment can include one or more ethylene groups and / or one or more comonomers. In various examples, 0 mol% of contaminants are present. In various examples, the contaminants are 1 mol% or less, 2 mol% or less, 3 mol% or less, 4 mol% or less, 5 mol% or less, 6 mol% or less, 7 mol% or less, 8 mol% or less, 9 mol% or less, 10 mol% or less, 11 mol% or less, 12 mol% or less, 13 mol% or less, 14 mol% or less, 15 mol% or less, 16 mol% or less, 17 mol% or less, 18 mol% or less, 19 mol% or less, 20 mol% or less, 21 mol% or less, 23 mol% or less, 24 mol% or less, 25 mol% or less.

[0049] In one aspect, the present invention provides a polymer mixture (e.g., a graft copolymer mixture). The polymer mixture can be a mixture of the graft copolymer of the present invention and one or more semi-crystalline polyethylenes, a mixture of the graft copolymer of the present invention and one or more iPPs, or a mixture of the graft copolymer of the present invention, one or more semi-crystalline polyethylenes, and one or more iPPs.

[0050] A variety of semi-crystalline polyethylenes can be used in the polymer mixture (e.g., the graft copolymer mixture). Non-limiting examples of semi-crystalline polyethylenes include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), medium density polyethylene (MDPE), ultra-high molecular weight polyethylene (UHMWPE), derivatives / analogs of any of the foregoing, and combinations thereof.

[0051] The polymer mixture of the present invention can comprise the graft copolymer of the present invention and semi-crystalline polyethylene (e.g., HDPE), or the graft copolymer of the present invention and isotactic polypropylene (iPP), or the graft copolymer of the present invention and one or more semi-crystalline polyethylenes (e.g., HDPE) and one or more iPPs. Without intending to be bound by any particular theory, the graft copolymer acts as a compatibilizer. The polymer mixture can comprise from 0.1 to 20% by weight of the graft copolymer, based on the total weight of the polymer mixture, including all 0.1% by weight values and ranges therebetween (e.g., 0.1 to 10% by weight or 0.1 to 5% by weight) (e.g., 0.1% by weight, 0.2% by weight, 0.3% by weight, 0.4% by weight, 0.5% by weight, 0.6% by weight, 0.7% by weight, 0.8% by weight, 0.9% by weight, 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 11% by weight, 12% by weight, 13% by weight, 14% by weight, 15% by weight, 16% by weight, 17% by weight, 18% by weight, 19% by weight, or 20% by weight). Without intending to be bound by any particular theory, the polymer mixture can exhibit enhanced tensile strength at a graft copolymer loading of from 0.1 to 10% by weight of the graft copolymer, based on the total weight of the polymer mixture, including all 0.1% by weight values and ranges therebetween (e.g., 0.1 to 5% by weight or 1% by weight or 5% by weight).

[0052] The polymer mixture can comprise various domains. These domains can be crystalline, semi-crystalline, or amorphous.

[0053] The polymer mixture comprising the graft copolymer of the present invention, one or more semi-crystalline polyethylenes, and one or more iPPs may have various weight ratios (w / w) of iPP:semi-crystalline polyethylene (e.g., iPP / PE). This iPP / PE ratio may be from 1 / 99 to 99 / 1, including all ratio values and ranges therebetween (e.g., 99 / 1, 95 / 5, 90 / 10, 80 / 20, 70 / 30, 60 / 40, 50 / 50, 40 / 60, 30 / 70, 20 / 80, 10 / 90, 5 / 95, or 1 / 99) (e.g., 30 / 70 iPP / PE such as 30 / 70 iPP / HDPE).

[0054] In one aspect, the graft copolymer is produced by the method of the present invention. The method of the present invention may include the polymerization of iPP and ethylene.

[0055] The method for producing a graft copolymer includes generating a reaction mixture comprising one or more macromonomers (e.g., iPP macromonomer) and a solvent, heating the reaction mixture, adding a monomer (e.g., ethylene by monomer feed), wherein the reaction mixture is pressurized to 1 to 2000 psig (including all values and ranges of 0.1 psig therebetween (e.g., 1 to 1500 psig, 1 to 1000 psig, 1 to 500 psgi, 1 to 300 psig, 1 to 100 psig)), adding a catalyst, optionally adding a cocatalyst to the reaction mixture, and optionally suppressing the reaction (e.g., adding a quenching agent (e.g., methanol) to the reaction mixture). In various examples, the macromonomer may be generated in situ during the production of the graft copolymer. In various examples, the various components in the reaction mixture (e.g., monomer, macromonomer, monomer, catalyst, cocatalyst, and solvent) are added in any order.

[0056] Macromonomers can be produced by various methods known in the art. For example, macromonomers can be produced using a catalyst that undergoes β-methyl elimination in the homopolymerization of propylene. Such a method is disclosed in JP 2009299045A, and the part related to the homopolymerization of propylene is incorporated herein by reference.

[0057] Various catalysts and / or cocatalysts and / or combinations of catalysts and cocatalysts can be used. The catalyst may be any catalyst capable of alkene polymerization, and non-limiting examples include metallocene catalysts or non-metallocene catalysts (e.g., pyridylamide hafnium catalysts), and cocatalysts (e.g., activators) are methylaluminoxane, N,N-dimethylanilinium borate salts, trityl borate salts, and / or Lewis acids (e.g., B(C 6 F 5 ) 3 etc.), and combinations thereof may also be used.

[0058] In an exemplary example, the graft copolymer may be produced by copolymerization of an iPP macromonomer with ethylene using a pyridylamide hafnium precatalyst and B(C 6 F 5 ) 3 . The copolymerization can occur at a temperature of about 70 °C.

[0059] In various examples, the copolymerization may be cooled before all of the macromonomer is consumed. The compounding amount of the macromonomer may range from 10% to 99%, including all values and ranges of 0.1% therebetween (e.g., 10% to 65%). In various other examples, any of the copolymerizations proceeds to completion, at which time the macromonomer (e.g., iPP macromonomer) is sufficiently consumed, the monomer (e.g., ethylene) is sufficiently consumed, or both the macromonomer and the monomer are sufficiently consumed.

[0060] The present invention describes manufacturing a graft copolymer via a "grafting onto" approach, although other methods for manufacturing a graft copolymer may be used. For example, the methods of the present invention can be modified for "graft to" and "graft from" methods. Such modifications will be apparent to those skilled in the art. For example, additional methods for preparing graft copolymers are described in Macromolecules 2020, 53(15), 6353-68 by Brant et al., and the portions related to the synthesis of graft copolymers are incorporated herein by reference.

[0061] In one aspect, the present invention provides a method for manufacturing a polymer mixture (e.g., a graft copolymer mixture). The graft copolymer mixture can be manufactured by melt mixing the graft copolymer of the present invention with semi-crystalline polyethylene, or the graft copolymer of the present invention with iPP, or the graft copolymer of the present invention with iPP and semi-crystalline polyethylene.

[0062] The melt blending method may include generating a reaction mixture of iPP and the graft copolymer of the present invention, or semi-crystalline polyethylene (e.g., HDPE) and the graft copolymer of the present invention, or iPP and semi-crystalline polyethylene (e.g., HDPE) and the graft copolymer of the present invention. This graft copolymer may be at a concentration of 0.1 to 20% by weight based on the total weight of the polymer mixture, and all 0.1% by weight values and ranges therebetween (e.g., 0.1 to 10% by weight or 0.1 to 5% by weight) (e.g., 0.1% by weight, 0.2% by weight, 0.3% by weight, 0.4% by weight, 0.5% by weight, 0.6% by weight, 0.7% by weight, 0.8% by weight, 0.9% by weight, 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 11% by weight, 12% by weight, 13% by weight, 14% by weight, 15% by weight, 16% by weight, 17% by weight, 18% by weight, 19% by weight, or 20% by weight) are included. Then, this reaction mixture is heated and pressurized for a certain time (e.g., 5 minutes) (e.g., heated to 180°C) to form a coherent film. Then, this film is heated (e.g., 190°C) and an inert gas (e.g., argon) is passed through for a specific residence time (e.g., 8 minutes at 130 rpm) and may be fed through a mixer (e.g., a twin-screw mixer, which may be a micro mixer such as a twin-screw micro mixer). Then, the material thus obtained is extruded through a die (e.g., various die molds, such as a die with a 2.5 mm diameter, etc.) and cooled to obtain a mixture. Then, this mixture can be pressed for a certain time (e.g., 5 minutes) while being heated (e.g., 180°C).

[0063] The hot polymer mixture can be cooled at various rates. While not intending to be bound by a particular theory, it is believed that when the heated polymer mixture is cooled at a fast rate, a polymer mixture having desirable characteristics (e.g., high tensile strength) can be obtained. For example, the melt-mixed graft copolymer mixture is cooled at 5 °C / min to 30 °C / min, including all values and ranges of 0.1 °C / min therebetween (e.g., 10 °C / min to 25 °C / min or 23 °C / min). However, the cooling is not limited to rates within this range. The cooling rate can vary depending on the size and shape of the polymer mixture (e.g., the article containing the polymer mixture). In various embodiments, this hot polymer mixture is cooled at 1 °C / hr to 100 °C / min. While not intending to be bound by a particular theory, faster cooling is believed to prevent phase separation (e.g., phase separation of iPP) in the polymer mixture, thereby imparting high tensile strength.

[0064] In various embodiments, the polymer mixture of the present invention may be "recycle ready". For example, a polyethylene article or a polypropylene material can be used in the method of the present invention so that the article can be recycled. For example, a recyclable polyethylene article can include a mixture containing polyethylene and a graft copolymer, and the recyclable polyethylene article can enter a recycle stream and be easily mixed with recycled polypropylene to produce a mixture. For example, a recyclable polypropylene article can include a mixture containing polypropylene and a graft copolymer, and the recyclable polypropylene article can enter a recycle stream and be easily mixed with recycled polyethylene to produce a mixture.

[0065] In one aspect, the present invention provides a product. This product (e.g., an article) includes the graft copolymer of the present invention or the polymer mixture of the present invention (e.g., a graft copolymer mixture).

[0066] The product can include the graft copolymer of the present invention or the polymer mixture of the present invention (e.g., graft copolymer mixture). The product can be in any three-dimensional (3D) shape. Specific examples of the product include, but are not limited to, containers (e.g., cups, bottles, boxes, pallets, coolers, etc.), lids / caps (e.g., screw caps for bottles), chairs, tableware (e.g., plates, forks, knives, spoons, etc.), traffic cones, bags, films, packaging materials, agricultural wraps, packing materials, toys, pipes, cable insulations, etc. Such articles can be Recyclable as well.

[0067] The following statements provide various examples and embodiments of the present invention. Statement 1. A graft copolymer comprising a semi-crystalline polyethylene (PE) segment and a plurality of semi-crystalline isotactic polypropylene (iPP) segments, wherein each semi-crystalline isotactic polypropylene segment is covalently bonded to the semi-crystalline polyethylene segment and the iPP segments are pendant groups. Statement 2. The graft copolymer according to Statement 1, wherein the number average molecular weight (Mn) of the graft copolymer is 25 to 1000 kDa, including all integer values and ranges therebetween (e.g., 50 to 500 kDa). Statement 3. The graft copolymer according to Statement 1 or 2, wherein the number average molecular weight (Mn) of the portion of the PE segment between each iPP segment is 1 to 100 kDa, including all 0.1 Da values and ranges therebetween. Statement 4. The graft copolymer according to any one of the previous statements, wherein the average number of iPP segments is 1 to 50, including all 0.1 values and ranges therebetween. Statement 5. The graft copolymer according to any one of the previous statements, wherein the number average molecular weight (Mn) of the iPP segments is 1 to 50 kDa, including all integer values and ranges therebetween. Statement 6. The graft copolymer according to any one of the preceding statements, wherein the number average (Mn) molecular weight of the iPP segment is about 6 kDa and the average number of iPP segments is about 16. Statement 7. The graft copolymer according to any one of the preceding statements, wherein the graft copolymer has the following structure:

Chemical formula

Chemical formula

[0068] The following examples are presented to illustrate the present invention. The present invention is not intended to be limited to any matter.

Example

[0069] The following examples provide an explanation of a method for producing a graft copolymer and a polymer mixture.

[0070] The PE-g-iPP graft copolymer (Figure 1b) may be a suitable compatibilizer, enabling the use of non-living polymerization for both the production of macromonomers and graft copolymers, and thereby potentially replacing living polymerization. Important variables of the GCP include the iPP graft length, the number of grafts per chain, the average distance between grafts, the branch distribution, and the backbone length (Figure 1c). These results are described herein.

[0071] A series of allyl-terminated iPP macromonomers were prepared using ansa-metallocene catalysts that can undergo β-chlorine elimination in the presence of vinyl chloride chain transfer agents. These macromonomers were characterized by gel permeation chromatography (GPC) and prepared over a range of molecular weights (Mn = 6 - 28 kg / mol) by varying the amount of vinyl chloride added (Table 2).

[0072] A series of graft copolymers were prepared with a pyridylamide hafnium pre-catalyst (1) and B(C 6 F 5 ) 3It was prepared by copolymerization of ethylene and iPP macromonomer (Table 1). To ensure the solubility of the macromonomer and the graft copolymer, this copolymerization was carried out at 70 °C, and the reaction was stopped before complete consumption of all macromonomers to minimize the gradual decrease of the resulting graft copolymer. GPC curve fitting was used to estimate the amount of residual unreacted macromonomer in the mixture and to calculate the average number of grafts incorporated per polymer chain. The amount of incorporated macromonomer was in the range of 12 - 60%. A complete explanation of the residual macromonomer quantification is provided below (Figures 7, 8 and Table 3).

[0073] Table 1. Synthesis and Characterization of Graft Copolymers

Table 1

[0074] The number of grafts incorporated into the chain can be adjusted by regulating the macromonomer concentration in the polymerization (Table 1, Entries 4 - 6, 8 - 10). The polyethylene weight fraction can be adjusted by varying the ethylene pressure (Table 1, Entries 1 vs. 2; 6 vs. 7; 10 vs. 11). To determine whether the grafts are randomly distributed along the main polymer chain, control experiments were conducted by stopping the polymerization early. The polymers synthesized using this method have a low number of grafts per chain, suggesting that the incorporation of macromonomer is continuous throughout the experiment (Table 1, Entries 1 and 3). However, for the highest molecular weight macromonomers (Mn = 26 - 28 kDa), it was observed that although the total molecular weight increased at high macromonomer concentrations, the number of grafts did not change up to a reaction time of 15 - 30 minutes (Entries 12 and 10 in Table 1, respectively). In these cases, it was hypothesized that the macromonomer co-precipitated with the growing polymer chains, inhibiting further incorporation. Since most of the incorporation of high molecular weight macromonomers occurs at the start of the polymerization, this can result in graft copolymers with a higher density of grafts located towards one end of the polymer chain.

[0075] PP and HDPE homopolymers undergo phase separation when mixed in the melt. To investigate the influence of GCP on the mixing structure, a mixture of iPP and HDPE (iPP / HDPE = 30 / 70 w / w) was melt-mixed in the presence of a graft copolymer (5 wt%). The morphology of this mixture was imaged by transmission electron microscopy (TEM). The mixture was stained with RuO 4 solution and then frozen and cryomicrotomed. Representative TEM micrographs are shown in Figs. 2 and 10 - 11, where the iPP minority phase appears as brighter islands in the HDPE matrix. For a given graft length, samples with a higher number of grafts per chain show smaller dispersed phases (Fig. 2c). For mixtures containing 5 wt% iPP 26-28k GCP, the average iPP domain diameter decreased from 2.5 to 1.2 μm as the average number of grafts / chain increased from 0 to 9. Similar results were observed for iPP 14 and iPP 6 grafts (Fig. 13). To compare with 5 wt% GCP, the iPP droplet size of a mixture sample containing 1 wt% 398 PE 15 -g- 9.3 iPP 26 GCP was analyzed by atomic force microscopy (AFM) (Fig. 12). The average droplet size was approximately 2 μm, and a slightly smaller average droplet size was observed when cooled at 23 °C / min vs 10 °C / min (see below) after melt pressing, presumably due to further domain coarsening during slow cooling. All these results indicate that properly designed GCPs lower the dispersed phase droplet size, presumably by localizing at the interface and reducing the interfacial tension of the iPP / HDPE mixture, in a typical manner of a good compatibilizer.

[0076] Individually, the iPP and HDPE homopolymer samples used herein exhibited ductile behavior with strain hardening at larger elongations (i.e., strain at break > 600%) (Panels Al, Bl, Cl, Dl in Figure 14). However, when these polymers were melt-mixed without a compatibilizer (iPP / HDPE = 30 / 70 w / w), the resulting mixture showed a decrease in ductility (i.e., strain less than 20% at break) compared to the neat material (Panels z and El in Figure 14). Ideally, the tensile behavior (i.e., elongation and toughness) of the compatibilized mixture should be intermediate between that of the HDPE and iPP homopolymers and be characteristic of a good compatibilizer. To test the effectiveness of the GCP, the mechanical properties of the iPP / HDPE mixture were first evaluated with 5 wt% GCP (Figure 3a and 14). Such a relatively high GCP loading was selected to investigate the effects of graft length and density. For all three graft lengths, improved elongation was achieved in mixtures compatibilized with graft copolymers containing a larger number of grafts (Figure 3a). As an example, for the GCP containing 6 kDa iPP grafts, when the average number of grafts per chain was increased from 10 (Panel B in Figure 14) to 16 (Panels A in Figure 3a and 14), the strain at break increased from 100% to 950%. It is noteworthy that for the two samples in Figure 3a, AFM images of the cross-section near the fracture surface (i.e., within 1 cm) (Figure 3b and 3c, 15) showed that the iPP droplets were deformed into very elongated ellipses that were elongated in the tensile direction. Qualitatively, the droplets appeared to deform in proportion to the deformation of the HDPE matrix. No detectable voids indicating cavitation were present at the interface between the deformed iPP droplets and the HDPE matrix. Without intending to be bound by a particular theory, such observations are thought to be consistent with the toughness and high elongation of these compatibilized mixtures, as the GCP can localize at the interface and facilitate strong interfacial adhesion that can assist in stress transfer between the two phases.

[0077] The influence of graft length on tensile properties was evaluated (Figure 4). As the molecular weight of the graft increased from 6 kDa to 26 kDa, higher molecular weight macromonomer variants required fewer grafts to achieve improved toughness. Similar tensile properties were obtained using 16 grafts per chain of 6 kDa grafts (Table 1, entry 1) and 11 grafts per chain of 14 kDa grafts (Table 1, entry 6), and for 26 kDa grafts, a high strain at break was observed with only an average of 5.6 grafts / chain (Table 1, entry 11).

[0078] The influence of graft number and length was demonstrated and the mechanical compatibilization efficiency at low loadings of the graft copolymer was investigated. Under base cooling conditions (10 °C / min), mixtures containing 1 wt% GCP showed lower strain at break compared to 5 wt% samples prepared at the same cooling rate (10 °C / min, Figure 5a). It was hypothesized that at lower GCP loadings, the coverage of the GCP was reduced, thereby decreasing the ability to transmit stress across the interface.

[0079] Also, the influence of the cooling rate of the melt-pressed samples on tensile properties was examined. At 1 wt% GCP loading, faster cooling (23 °C / min) yielded samples with improved toughness compared to those cooled more slowly (10 °C / min) (Figure 5b and 14). At 1 wt% 260 PE 8.8 -g- 11 iPP 14For filling, the samples showed 800% strain at break compared to 250% at a slower cooling rate for the same additive. This is an expected result since slow cooling gives rise to polymers with higher crystallinity and a more brittle behavior, as is evident from the stress-strain curves for pure iPP and HDPE (Figure 5). For all samples, the modulus values (stress) between about 20% and 500 - 800% strain for the faster cooling rate (Figure 5b), with and without using GCP, were observed to be about 15% lower than those observed at the slower cooling rate (Figure 5a). This seems to reflect the lower crystallinity at the faster cooling rate. The iPP and HDPE homopolymers showed higher strain at break and higher strain hardening when cooled at 23 °C / min rather than 10 °C / min, which is consistent with a higher rubbery amorphous content. However, the 30 / 70 iPP / HDPE blend showed similar brittle, tensile behavior at both cooling rates (inserted in the figure). The overall toughness of the best GCP-containing blends is similar to that observed for blends containing linear PE-iPP-tetra- and hexablock copolymers.

[0080] Results from tensile tests, TEM, and AFM studies indicate that the PE-g-iPP copolymer additive acts as a good compatibilizer for iPP / HDPE blends. Generally, increasing the number of grafts and the graft length increases the tensile strength of the compatibilized blend. For comparison, the tensile strength for the rapidly cooled 1 wt% GCP-containing blend is approximately equivalent to that observed for well-defined PE-iPP tetra- and hexablocks. These findings suggest that an efficient compatibilizer for HDPE and iPP can be prepared via a non-living polymerization route, ultimately providing a more economical synthesis of these useful materials.

[0081] General considerations: All manipulations of air- and / or moisture-sensitive compounds were carried out under a nitrogen atmosphere in an MBraun Labmaster glove box. 1 H NMR and13 The 1H NMR spectrum was recorded on a 500 MHz Bruker AV III HD equipped with a broadband Prodigy Cryoprobe using the residual non-deuterated solvent signal as a reference [Cl 2 CDCDCl 2 (d 2 -TCE): 6.0 ppm ( 1 H), 73.78 ppm ( 13 C). All polymer samples were quantified at 130 °C 1 1H NMR and 13 13C{1H} NMR spectroscopic analysis was used to analyze in d 2 -TCE in a 5 mm tube. MestreNova software was used for spectral processing. High temperature gel permeation chromatography (GPC) was performed on an Agient PL-GPC 220 equipped with a refractive index (RI) detector and three PL-Gel Mixed B columns. The GPC columns were eluted at 150 °C with 1,2,4-trichlorobenzene (TCB) containing 0.01 wt% di-tert-butylhydroxytoluene (BHT) at 1.0 mL / min. Samples were prepared at a concentration of 1.0 mg / mL in TCB (along with BHT) unless otherwise stated and heated at 150 °C for at least 1 hour before injection. Calibration of the GPC data was performed using monomodal polyethylene standards from Varian and Polymer Standard Services. Differential scanning calorimetry (DSC) measurements were performed on a Mettler Toledo Polymer DSC instrument. Polymer samples containing approximately 5 mg in crimped aluminum pans were prepared for each experiment. The DSC samples were heated to 200 °C, held at temperature for 10 minutes to erase the thermal history, cooled to 20 °C, and then heated again to 200 °C. The cooling and heating steps were maintained in a nitrogen atmosphere at a rate of 10 °C / min. The crystallization temperature (T c ) and melting temperature (T m ) were obtained from the first cooling cycle and the second heating cycle, respectively, using STARe software.

[0082] Compression molding was carried out using a 4120 hydraulic unit Carver press and a stainless-steel die mold. The Mylar protective sheet was obtained from Carver. The uniaxial tensile elongation was carried out using a Shimadzu Autograph AGS-X tensile testing machine. The molten mixture was prepared using a vertical conical counter-rotating twin-screw batch mixer equipped with a 2.5 mm diameter extrusion die and a 5 g capacity mixing chamber. All polymer treatments were carried out with pristine materials (i.e., without added BHT, other antioxidants, or additives). Details of further experiments are provided in the appropriate sections below.

[0083] Materials: Toluene was purified with columns of alumina and copper (Q5) and molecular sieves before use. Ethylene (Matheson, Matheson purity) and propylene (Airgas, polymer grade) were purified with a column of copper Q5 and 4 Å molecular sieves. Vinyl chloride was purchased from Synquest Laboratories and used as received. B(C 6 F 5 ) 3 was obtained from TCI Chemicals and used as received. The pyridylamide hafnium catalyst (1) was prepared according to a known method. rac-Dimethylsilanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride (rac-MPSBI-ZrCl 2) was synthesized according to literature procedures. Methylaluminoxane (MAO) was obtained from Albemarle as a 30 wt% solution in toluene and dried at 40 °C under vacuum for at least 12 h. (Caution: Residual trimethylaluminum must be removed during this step by carefully evacuating the solvent trap and quenching with iPrOH). Diisobutylaluminum phenolate (DIBAP) was prepared in a glove box by adding BHT (0.220 g, 1.00 mmol, 1.00 equiv.) in toluene (2 mL) to Al(iBu)3 (0.198 g, 1.00 mmol, 1.00 equiv.) in toluene (2 mL) and stored in a vial sealed with a Teflon cap. Isotactic polypropylene (iPP) was obtained from Dow Chemical Company (H314-02Z; Mn=100 kg / mol; D=4.1; Tm=163°C; MFI=2.0 g / 10 min, 2.16 kg, 230°C). High density polyethylene (HDPE) was obtained from Dow (DMDA 8904; Mn=22 kg / mol; D=3.8; Tm=131°C; MFI=4.4 g / 10 min, 2.16 kg, 190°C).

[0084] [ka] The general synthesis of the macromonomers was adapted from known methods.

[0085] In a glove box, MAO (0.116 g, 2.00 mmol) and PhMe (100 mL or 200 mL) were charged into a 6 oz Fisher-Porter bottle. Outside the glove box, a quantity of vinyl chloride was condensed into a pre-weighed flask (Caution: vinyl chloride is highly toxic. The fume hood was kept under high evacuation for the duration of the experiment). The Fisher-Porter bottle was pressurized with 15 psig propylene for 15 min. rac-MPSBI-ZrCl in PhMe (2.5 mL) was added. 2A solution of (Zr-cat) (1.40 mg, 2.00 mmol) was added to the flask. The reaction mixture was stirred while continuously feeding propylene at room temperature for a certain period of time. MeOH (5 mL) was added to stop the reaction, and the reaction mixture was poured into MeOH (200 mL) and stirred for 3 hours. The precipitated polymer was dried at 40 °C for 4 hours, then redissolved in boiling PhMe and filtered through celite. After cooling to room temperature, the precipitate was collected by filtration and vacuum dried at 40 °C until a constant weight was reached. Then, this macromonomer was dried at 80 °C under high vacuum for 14 hours and transferred to a glove box for graft copolymer synthesis (see Table 2 for details).

[0086] The allyl termini of the polymer were confirmed by 1 1H-NMR for the selected samples.

[0087]

Table 2

[0088] General synthetic method of graft copolymer: Inside the glove box, iPP macromonomer (0.50 - 2.00 g), DIBAP (0.1 mL), and PhMe (50 or 100 mL) were loaded into a 6-ounce Fisher-Porter bottle. Then, the reaction vessel was heated to 100 °C in an oil bath until all the macromonomer was dissolved (about 30 minutes), and then maintained at 100 °C for an additional 15 minutes. Then, this reaction vessel was transferred to an oil bath at 70 °C and pressurized with ethylene at the set pressure for 15 minutes. During this time, in the glove box, pyridylamide hafnium catalyst (6.40 mg, 10.0 μmol) and cocatalyst B (C 6 F 5 ) 3(5.40 mg, 10.5 μmol) was mixed in a 20 mL scintillation vial and dissolved in PhMe (3 mL). This solution was reacted for 5 minutes, transferred to an airtight syringe, and added to a Fisher-Porter bottle. The reaction mixture was stirred at 70 °C for 30 minutes under a continuous supply of ethylene. At the end of the reaction, the monomer supply was stopped, the Fisher-Porter bottle was evacuated, and the polymerization was terminated using MeOH (4 mL). The product was precipitated into MeOH (200 mL) and stirred for 2 hours. The polymer was collected by filtration and dried in vacuo at 40 °C for 4 hours.

[0089] 185 PE 5.2 -g- 16 iPP 6 (Table 1, Entry 1) According to the above method, 6K-iPP (Table 2, Entry 2 (1.0 g), PhMe (50 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 30 minutes. A polymer mixture of 1.33 g with 40% of the macromonomer incorporated and having 16 grafts per chain was obtained (see Table 3 for details).

[0090] 221 PE 15 -g- 10 iPP 6 (Table 1, Entry 2) According to the above method, 6K-iPP (Table 2, Entry 2) (1.0 g), PhMe (50 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (20 psig) were mixed at 70 °C for 30 minutes. A polymer mixture of 1.88 g with 40% of the macromonomer incorporated and having 10 grafts per chain was obtained (see Table 3 for details).

[0091] 63PE5.5-g-5.0iPP6 (Table 1, Entry 3) According to the above method, 6K-iPP (Table S1, Entry 2) (1.0 g), PhMe (50 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 15 minutes. 21% of the macromonomer was incorporated, and 1.20 g of a polymer mixture having 5 grafts per chain was obtained (see Table S2 for details).

[0092] 164 PE 13 -g- 5.5 iPP 14 (Table 1, Entry 4) According to the above method, 14K-iPP (Table 2, Entry 3) (0.5 g), PhMe (50 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 30 minutes. 40% of the macromonomer was incorporated, and 0.73 g of a polymer mixture having 5.5 grafts per chain was obtained (see Table 3 for details).

[0093] 210 PE 8.9 -g- 8.8 iPP 14 (Table 1, Entry 5) According to the above method, 14K-iPP (Table 2, Entry 3) (0.75 g), PhMe (50 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 30 minutes. 53% of the macromonomer was incorporated, and 1.04 g of a polymer mixture having 8.8 grafts per chain was obtained (see Table 3 for details).

[0094] 260PE 8.8 -g- 11 iPP 14 (Table 1, Entry 6) 14K-iPP (Table 2, Entry 4) (1.0 g), PhMe (50 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 30 minutes. 60% of the macromonomer was incorporated, and 1.46 g of a polymer mixture having 11 grafts per chain was obtained (see Table 3 for details).

[0095] 213 PE 57 -g- 2.2 iPP 14 (Table 1, Entry 7) 14K-iPP (Table 2, Entry 4) (1.0 g), PhMe (50 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (20 psig) were mixed at 70 °C for 30 minutes. 12% of the macromonomer was incorporated, and 1.73 g of a polymer mixture having 2.2 grafts per chain was obtained (see Table 3 for details).

[0096] 364 PE 74 -g- 2.9 iPP 26 (Table 1, Entry 8) 26K-iPP (Table 2, Entry 5) (1.0 g), PhMe (100 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 30 minutes. 26% of the macromonomer was incorporated, and 1.99 g of a polymer mixture having 2.9 grafts per chain was obtained (see Table 3 for details).

[0097] 298 PE 30 -g- 4.6 iPP 28 (Table 1, Entry 9) 28K-iPP (Table 2, Entry 6) (1.5 g), PhMe (100 mL), DIBAP (0.1 mL), [Hf] (6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 30 minutes. 29% of the macromonomer was incorporated, and 2.05 g of a polymer mixture having 4.6 grafts per chain was obtained (see Table 3 for details).

[0098] 398 PE 15 -g- 9.3 iPP 26 (Table 1, Entry 10) 26K-iPP (Table 2, Entry 5) (2.0 g), PhMe (100 mL), DIBAP (0.1 mL), [Hf] (6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 30 minutes. 40% of the macromonomer was incorporated, and 2.52 g of a polymer mixture having 9.3 grafts per chain was obtained (see Table 3 for details).

[0099] 413 PE 39 -g- 5.6 iPP 28 (Table 1, Entry 11) 28K-iPP (Table 2, Entry 6) (2.0 g), PhMe (100 mL), DIBAP (0.1 mL), [Hf] (6.4 mg), B(C 6 F 5 ) 3(5.4 mg) and ethylene (20 psig) were mixed at 70 °C for 30 minutes. 33% of the macromonomer was incorporated, and 3.08 g of a polymer mixture having 5.6 grafts per chain was obtained (see Table 3 for details).

[0100] 320 PE 9.8 -g- 8.2 iPP 28 (Table 1, Entry 12) According to the above method, 28K-iPP (Table 2, Entry 6) (2.0 g), PhMe (100 mL), DIBAP (0.1 mL), [Hf](6.4 mg), B(C 6 F 5 ) 3 (5.4 mg) and ethylene (10 psig) were mixed at 70 °C for 15 minutes. 46% of the macromonomer was incorporated, and 2.36 g of a polymer mixture having 8.2 grafts per chain was obtained (see Table 3 for details).

[0101]

Table 3

[0102] Analysis of graft copolymers: The graft copolymers in Table 1 contain residual unreacted macromonomer. The incorporation of the macromonomer and the molecular weight of the graft copolymer were estimated by fitting the experimental GPC curve of the polymer / macromonomer mixture to two overlapping Gaussian curves (see Figure 8). Such a method assumes symmetric peaks for both polymers in the polymer mixture. Subsequently, the unreacted macromonomer in the polymer can be quantified based on the experimental correlation between the macromonomer peak area and the GPC sample mass (see Figure 7). The Gaussian fitting is obtained by keeping the peak width and peak retention time of the fitted macromonomer constant compared to the data of the experimental macromonomer obtained from GPC, enabling automatic adjustment of the macromonomer peak area during fitting.

[0103] Mixture Preparation: Polymer pellets of Dow iPP (H314-02Z, 1.2 g), Dow HDPE (DMDA 8904, 2.8 g), and a set amount of graft copolymer powder (normalized based on the weight fraction in the graft copolymer / macromonomer mixture) were mixed and pressed at 180 °C for 5 minutes at minimum pressure to produce a coherent film. This film was fed into a twin-screw micro mixer at 190 °C with a steady flow of argon and a residence time of 8 minutes at 130 rpm. Then, this material was extruded through a 2.5 mm diameter die and air-cooled. Subsequently, the resulting mixture was pressed at 180 °C for 5 minutes at minimum pressure to produce a coherent film.

[0104] Manufacture of Dogbone Tensile Bars: The mixed film was loaded into a stainless-steel dogbone die (gage length = 10 mm, gage width = 2.6 mm, gage thickness = 0.6 mm) and pressed on a Carver press hot plate at 180 °C for 5 minutes at ~52 MPa. While maintaining this pressure, the sample was cooled with water circulation (at ~10 °C / min unless otherwise specified). The sample was taken out and trimmed using a razor blade.

[0105] Morphology Analysis of the Blend: To characterize the blend morphology using transmission electron microscopy (TEM), the as-received tensile bars were cryo-sectioned at -120 °C on a Leica EM UC6 ultramicrotome equipped with a model FC-S Cryo attachment to obtain a smooth surface. Then, the specimens were attached to a vial cap with double-sided tape and stained with RuO 4 solution in a sealed vial. This RuO 4 solution typically contains 15 mg of RuCl 3It was newly prepared by mixing with 2 mL of sodium hypochlorite. After staining for 2 hours, the sample was cryo-microtomed using a microstar diamond knife to obtain ultra-thin sections (with a thickness of around 70 nm). A Tecnai G2 Spirit Bio Twin microscope was used to image the thin sections at an accelerating voltage of 120 kV. Droplet size analysis was performed on the TEM micrograph images j. For each sample, at least 250 droplets were analyzed, the area was determined for each droplet, and the diameter was calculated assuming a perfect circle for each droplet. A histogram of the droplet size distribution was plotted and fitted to a log-normal distribution. Representative TEM micrographs and size distributions are shown in Figures 10 and 11.

[0106] Atomic force microscopy: Atomic force microscopy (AFM) was performed to characterize the mixed morphology of the tensile test samples before and after the tensile test. The as-manufactured samples were used without stretching. The stretched samples were first embedded in epoxy for observation under AFM along the uniaxial stretching direction. Both samples were microtomed at -140 °C on a Leica EM UC 6 ultramicrotome equipped with a model FCS Cryo attachment. To obtain a smooth surface, a series of consecutive cuts were made using a glass knife with a 1 μm step length first and then a Diatome diamond knife with a step length of 100 nm. AFM was performed using a Bruker Nanoscope V in AC mode. The samples were examined in repulsive mode using a silicon chip (HQ:NSC36 / AL BS, NanoAndMore USA Corp.) with a radius of 8 nm, a resonance frequency of 130 kHz, and a force constant of 2 N / m. For the as-manufactured samples, droplet size analysis was performed using ImageJ, and at least 100 droplets were included in the size calculation.

[0107] Mechanical testing: The mechanical study was carried out using a Shimadzu Autograph AGS-X tensile testing machine that was extended at a crosshead speed of 10 using TrapeziumX v.1.5.1 software. Representative traces are shown in Figures 3 and 5, and the compiled individual traces are shown in Figure 10 below.

[0108]

Table 4

[0109] Although the present invention has been described with respect to one or more specific embodiments and / or examples, it will be understood that other embodiments and / or examples of the present invention may be made without departing from the scope of the present invention.

Claims

1. A graft copolymer comprising a semi-crystalline polyethylene (PE) main chain and a plurality of semi-crystalline isotactic polypropylene (iPP) segments, wherein each semi-crystalline iPP segment is covalently bonded to a semi-crystalline polyethylene (PE) segment constituting the semi-crystalline PE main chain, and moreover, the semi-crystalline iPP segment is a pendant group, The graft copolymer.

2.

3. The number average molecular weight (M n ) of the graft copolymer is 25 to 1000 kDa, and the graft copolymer according to claim 1.

4. The number average molecular weight (M n ) of the portion of the semi-crystalline PE segments between the semi-crystalline iPP segments is from 1 to 100 kDa, the graft copolymer according to claim 1.

5. The graft copolymer according to claim 1, wherein the average number of the semi-crystalline iPP segments is 1 to 50.

6. The number average molecular weight (M n ) of the semi-crystalline iPP segment is 1 to 50 kDa, and the graft copolymer according to claim 1.

7. The graft copolymer according to claim 1, wherein the graft copolymer has the following structure: 【Chemical 1】 In the above formula, m is 36 to 3600, and n is 24 to 1200 The graft copolymer according to claim 1, comprising.

8. The graft copolymer according to claim 1, wherein the end group of the graft copolymer is a saturated or unsaturated aliphatic group.

9. The graft copolymer according to any one of claims 1 to 7, wherein the semi-crystalline PE segment contains 9 mol% or less of contaminants.

10. The graft copolymer according to claim 8, wherein the semi-crystalline PE segment contains 5 mol% or less of contaminants.

11. The graft copolymer according to claim 9, wherein the semi-crystalline PE segment contains 1 mol% or less of contaminants.

12. The graft copolymer according to any one of claims 8 to 10, wherein the semi-crystalline PE segment contains one or more polypropylene groups and / or one or more comonomers as the contaminants, and / or the semi-crystalline iPP segment contains one or more ethylene groups and / or one or more comonomers as the contaminants.

13. (A) One or more graft copolymers according to any one of claims 1 to 11 and one or more semi-crystalline polyethylenes, or (B) One or more graft copolymers according to any one of claims 1 to 11 and one or more isotactic polypropylenes (iPP), or (C) One or more graft copolymers according to any one of claims 1 to 11, one or more semi-crystalline polyethylenes, and one or more iPPs A graft copolymer mixture comprising.

14. The graft copolymer mixture according to claim 12, wherein the iPP / semi-crystalline polyethylene ratio in (C) is 1 / 99 to 99 / 1 (w / w).

15. The graft copolymer mixture according to claim 12, wherein the total concentration of the graft copolymer(s) of 1 or more is 0.1 to 20% by weight based on the total weight of the graft copolymer mixture.

15. A method for producing a graft copolymer, the production method comprising: forming a reaction mixture containing 1 or more iPP macromonomers and a solvent; heating the reaction mixture; adding ethylene to the reaction mixture; adding a catalyst and, optionally, a cocatalyst to the reaction mixture; and optionally suppressing the reaction and producing the graft copolymer according to any one of claims 1 to 11.

16. The method according to claim 15, wherein the iPP macromonomer has the following structure: [Chemical 2] In the above formula, n is 24 to 1200

17. The method according to claim 15, wherein the catalyst is an alkene polymerization catalyst.

18. The method according to claim 17, wherein the alkene polymerization catalyst is 1 or more metallocene catalysts and / or 1 or more non-metallocene catalysts.

19. The method according to claim 18, wherein the non-metallocene catalyst is a pyridylamide hafnium catalyst.

20. The method according to claim 15, wherein the cocatalyst is selected from methylaluminoxane, N,N-dimethylanilinium borate salt, trityl borate salt, Lewis acid, and combinations thereof.

21. The method according to claim 15, wherein the polymerization of the ethylene and the iPP macromonomer is completed before the consumption of all of the iPP macromonomers.

22. The method according to claim 21, wherein 10 to 99% of the iPP macromonomer is incorporated into the graft copolymer.

23. A method for producing the graft copolymer mixture according to any one of claims 12 to 14, the method comprising: (A) melting and mixing 1 or more graft copolymers with 1 or more semi-crystalline polyethylenes, or (B) melting and mixing 1 or more graft copolymers with 1 or more iPPs, or (C) melting and mixing 1 or more graft copolymers with 1 or more semi-crystalline polyethylenes and 1 or more iPPs to produce the graft copolymer mixture according to any one of claims 12 to 14.

24. The method according to claim 23, wherein the melt-mixed graft copolymer mixture is cooled at 1 °C / hour to 100 °C / min.

25. A product comprising the graft copolymer mixture according to any one of claims 12 to 14.

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