阅读说明：本技术 用作锂离子电池电解质的含二羰基侧基的丙烯酸酯聚合物 (Acrylate polymers containing dicarbonyl side groups for use as lithium ion battery electrolytes ) 是由 马拉·阿扎伽萨米 哈尼·巴萨姆·埃陶尼 库兰戴维路·斯瓦南丹 斯科特·艾伦·穆林 于 2020-02-14 设计创作，主要内容包括：本发明公开用作锂离子电池电解质的含二羰基侧基的丙烯酸酯聚合物。已经合成了新的含二羰基侧基的丙烯酸酯类聚合物。当这些聚合物与电解质盐组合时,这种聚合物电解质在锂电池单元中显示出优异的电化学氧化稳定性。它们的稳定性以及出色的离子传输性能使其特别适合用作高能量密度锂电池单元中的电解质。(The invention discloses an acrylate polymer containing dicarbonyl side groups and used as an electrolyte of a lithium ion battery. Novel acrylate polymers containing pendant dicarbonyl groups have been synthesized. When these polymers are combined with an electrolyte salt, the polymer electrolyte shows excellent electrochemical oxidation stability in a lithium battery cell. Their stability and excellent ion transport properties make them particularly suitable for use as electrolytes in high energy density lithium battery cells.)

1. A polymer, comprising:

the structure of the acrylate dicarbonyl polymer is described as follows:

wherein each R is₁Independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, and trifluoromethyl; and is

a. b, c and n are integers; a ranges from 1 to 100, b ranges from 0 to 10, c ranges from 2 to 10, and n ranges from 1 to 1000.

2. The polymer of claim 1, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

3. The polymer of claim 2, further comprising ceramic electrolyte particles.

4. The polymer of claim 1, wherein the polymer is crosslinked.

5. The polymer of claim 4, further comprising an electrolyte salt, wherein the polymer is an electrolyte.

6. A positive electrode, comprising:

a positive electrode active material; and

a catholyte comprising the electrolyte of claim 2;

wherein the positive electrode active material particles and the catholyte are mixed together.

7. The cathode of claim 6, wherein the catholyte further comprises a solid polymer electrolyte.

8. The positive electrode of claim 6, wherein the catholyte further comprises ceramic electrolyte particles.

9. The cathode of claim 6, wherein the catholyte is crosslinked.

10. The positive electrode of claim 6, wherein the positive electrode active material is selected from the group consisting of lithium iron phosphate, lithium metal phosphates, vanadium pentoxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, magnesium rich lithium nickel cobalt manganese oxide, lithium manganese spinel, lithium nickel manganese spinel, and combinations thereof.

11. The positive electrode according to claim 6, wherein the electrolyte salt is a lithium salt.

12. An electrochemical cell comprising:

an anode configured to absorb and release lithium ions;

a cathode comprising cathode active material particles, an electron conductive additive, and a first catholyte;

a current collector adjacent to an outer surface of the cathode; and

a separator region between the anode and the cathode, the separator region comprising a separator electrolyte configured to facilitate lithium ion movement back and forth between the anode and the cathode;

wherein the first catholyte comprises the electrolyte of claim 2, and the electrolyte salt is a lithium salt.

13. The electrochemical cell of claim 12, wherein the first catholyte further comprises a solid polymer electrolyte.

14. The electrochemical cell of claim 12, wherein the first catholyte and the separator electrolyte are the same.

15. The electrochemical cell of claim 12, wherein the separator electrolyte comprises a solid polymer electrolyte.

16. The electrochemical cell of claim 12, further comprising a cover layer between the cathode and the separator region, the cover layer comprising a second catholyte comprising the electrolyte of claim 2.

17. The electrochemical cell of claim 16, wherein the first catholyte and the second catholyte are the same.

18. The electrochemical cell of claim 12, wherein the anode comprises a material selected from the group consisting of lithium metal, lithium alloys, lithium titanate, graphite, and silicon.

19. The electrochemical cell of claim 12, wherein the first catholyte further comprises ceramic electrolyte particles.

20. The electrochemical cell of claim 12, wherein the first catholyte is crosslinked.

Technical Field

The present invention relates generally to electrolytes for lithium batteries, and more particularly to electrolytes particularly suitable for use in cathodes and at high voltages.

Background

More and more lithium battery manufacturers are using next generation cathode materials, such as NCA (lithium nickel cobalt aluminum oxide), NCM (lithium nickel cobalt manganese oxide) and high energy NCM (HE-NCM-magnesium rich lithium nickel cobalt manganese oxide) to exploit their potential high gravimetric energy density (up to 300-. Cells made with such oxidic cathode materials typically operate at higher voltages (e.g., up to 4.7V) than do cells of olivine cathode materials (e.g., LFP, lithium iron phosphate) (e.g., 3.6-3.8V). Electrolytes that are stable at the lower voltages of LFP cells can be difficult to operate at higher voltages, especially in the cathode. Oxidative forms of degradation may lead to capacity fade early in the life of the cell.

Therefore, there is a need to develop electrolytes that are particularly suitable for operating under the high voltage conditions of the next generation of cathode materials.

Disclosure of Invention

In one embodiment of the present invention, a polymer is disclosed. The polymer is an acrylate dicarbonyl polymer structure and is described as follows:

wherein each R is₁Independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, and trifluoromethyl; and a, b, c and n are integers; a ranges from 1 to 100; b ranges from 0 to 10; c ranges from 2 to 10; n ranges from 1 to 1000.

In some embodiments of the invention, any of the polymers described herein are combined with an electrolyte salt and can be used as a polymer electrolyte.

In some embodiments of the present invention, any of the polymer electrolytes described herein further comprise ceramic electrolyte particles.

In some arrangements, the polymers described herein are all crosslinked. In some arrangements, any of the polymers described herein are crosslinked and combined with an electrolyte salt to function as a polymer electrolyte.

In one embodiment of the present invention, the positive electrode includes a positive electrode active material; and a catholyte comprising any of the electrolytes described herein. The positive electrode active material particles and the catholyte are mixed together. The catholyte may also include a solid polymer electrolyte. The catholyte may also comprise ceramic electrolyte particles. The catholyte may be crosslinked. The catholyte may comprise an electrolyte salt that is a lithium salt.

The positive active material may be any one of lithium iron phosphate, lithium metal phosphate, vanadium pentoxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, magnesium rich lithium nickel cobalt manganese oxide, lithium manganese spinel, lithium nickel manganese spinel, and combinations thereof.

In another embodiment of the present invention, an electrochemical cell includes: an anode configured to absorb and release lithium ions; a cathode comprising cathode active material particles, an electron conductive additive, and a first catholyte; a current collector adjacent to an outer surface of the cathode; and a separator region between the anode and the cathode, the separator region comprising a separator electrolyte configured to facilitate lithium ion movement back and forth between the anode and the cathode. The first catholyte may include any of the electrolytes disclosed herein. The first catholyte may also include ceramic electrolyte particles. The first catholyte may be crosslinked. The electrolyte salt may be a lithium salt.

The first catholyte and/or separator electrolyte may also comprise a solid polymer electrolyte. In one arrangement, the first catholyte and the separator electrolyte are the same.

In one arrangement, there is a cover layer between the cathode and the separator region. The cover layer includes a second catholyte, which may be any of the electrolytes disclosed herein. The first catholyte and the second catholyte may be the same or may be different.

The anode may comprise any one of lithium metal, lithium alloy, lithium titanate, graphite, and silicon.

Drawings

The foregoing aspects and others will become apparent to those skilled in the art from the following description of the illustrative embodiments, when read in light of the accompanying drawings.

Figure 1 is a graph illustrating cyclic voltammetry data for some dicarbonyl-based small molecules according to some embodiments of the present invention.

Fig. 2 is a schematic diagram of one configuration of a lithium battery cell including an electrolyte used in both the cathode and the separator according to an embodiment of the invention.

Fig. 3 is a schematic view of another configuration of a lithium battery cell comprising a catholyte and a separator electrolyte different from the catholyte, according to an embodiment of the invention.

Fig. 4 is a schematic view of another configuration of a lithium battery cell including a catholyte and a cathode capping layer according to an embodiment of the present invention.

Detailed Description

Embodiments of the present invention are illustrated in the context of acrylate dicarbonyl polymers that may be used as electrolytes or electrolyte additives in lithium battery cells and the like. However, one skilled in the art will readily appreciate that the materials and methods disclosed herein will have application in many other situations where high voltage electrolytes are required, particularly where long term stability is important.

These and other objects and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.

All publications mentioned herein are incorporated herein by reference in their entirety for all purposes as if fully set forth herein.

In the present disclosure, the terms "negative electrode" and "anode" are both used to describe a negative electrode. Likewise, the terms "positive electrode" and "cathode" are both used to describe a positive electrode.

It should be understood that the term "lithium metal" or "lithium foil" as used herein for the negative electrode is intended to include pure lithium metal and lithium-rich metal alloys known in the art. Examples of lithium-rich metal alloys suitable for use as the anode include Li-Al, Li-Si, Li-Sn, Li-Hg, Li-Zn, Li-Pb, Li-C, or any other lithium metal alloy suitable for use in a lithium metal battery. Other negative electrode materials that may be used in embodiments of the present invention include materials into which lithium may be intercalated, such as graphite, and other materials that may absorb and release lithium ions, such as silicon, germanium, tin, and alloys thereof. Many of the embodiments described herein are directed to batteries having a solid polymer electrolyte that functions as both an electrolyte and a separator. As is well known in the art, batteries with liquid electrolytes use a different inactive separator material than the liquid electrolyte.

The following sentence pattern is used throughout this disclosure: each variable is independently selected from the list provided. Examples of such uses can be found with reference to the X groups in certain polymer structures of the present invention in which there are many X's. For example, "each X may be independently selected from hydrogen, fluoro, methyl, ethyl, isopropyl, and trifluoromethyl. "such structure is intended to mean that for a particular X in the structure, any of the groups in the list can be used. In selecting a group to be used for another X in the structure, any of the groups in the list can be used without regard to the selection made for the other X groups. Thus, the following arrangements are possible: all xs may be the same, all xs may be different, or some xs may be the same and some xs may be different.

The molecular weights given herein are number average molecular weights.

The term "solid polymer electrolyte" is used herein to refer to a polymer electrolyte that is solid at the cell operating temperature. Examples of useful cell operating temperatures include room temperature (25 ℃), 40 ℃, and 80 ℃.

In this disclosure, a range of values is given for a number of variables. It should be understood that the possible values of the various variables also include any range within the given range.

Based on repeated observation of Li in Molecular Dynamics (MD) simulations⁺Interaction with other atoms, it appears that Li⁺Coordinated to a portion of the negatively charged atoms in the polymer electrolyte. For example, in polyethylene oxide (PEO), Li⁺Coordinated to a portion of the negatively charged oxygen atoms in the PEO. Similarly, in the side chain dicarbonyl containing polyacrylates, Li⁺Coordinated to the oxygen of the carbonyl moiety, which is negatively charged.

Disclosed herein are pendant functionalized acrylate polymers that can be used as polymer electrolytes that can function at high voltages (> 4.2V). Polymers have attracted considerable attention for lithium ion battery cells due to their higher mechanical properties, flexibility and safety compared to their small molecule counterparts. However, most polymer systems used as electrolytes for lithium ion battery applications contain only monofunctional moieties either on the backbone or as pendant groups. The polymers disclosed herein include high voltage stable difunctional moieties (i.e., dicarbonyl systems, such as malonate and oxalate functional groups) as pendant groups on the acrylate backbone. Such bifunctional systems have an enhanced lithium ion binding capacity compared to monofunctional systems, and thus improve lithium ion transport properties.

Polyacrylate with functionalized side groups:

the general structure of acrylate polymers having pendant groups containing oxygen double bonds, such as malonates, oxalates, sulfonates, and phosphonates, useful as electrolytes is shown below.

Structure A

Each R is independently selected from the above list; a. b and c are integers having the above range; n is in the range of 1 to 1000An integer of (d); r₁Independently selected from hydrogen, methyl, ethyl, propyl, isopropyl and trifluoromethyl.

Examples of ceramic electrolytes that can be used in blends with electrolytes based on acrylate polymers having pendant oxygen-containing double bonds include, but are not limited to, those shown in table 1.

TABLE 1

Exemplary ceramic conductors for use as polymer electrolyte additives

Denotes the components mixed together

Polyacrylate with dicarbonyl side groups:

in some embodiments of the present invention, the general structure of the acrylate polymer with dicarbonyl side groups is shown below.

Each R₁Independently selected from hydrogen, methyl, ethyl, propyl, isopropyl and trifluoromethyl. a. b, c and n are integers; a ranges from 1 to 100; b ranges from 0 to 10; c ranges from 2 to 10; and n ranges from 1 to 1000.

In another embodiment of the present invention, particles of a ceramic electrolyte are mixed into a polyacrylate-based polymer electrolyte to form an enhanced composite electrolyte having excellent ion transport and mechanical properties. Such composite electrolytes can be used in the separator region or in the cathode in lithium battery cells. Examples of ceramic electrolytes that can be used in blends with polyacrylate-based electrolytes include, but are not limited to, those shown in table 1 above.

Voltage stability of dicarbonyl model systems

The high voltage (>4.2V) stability of these pendant functional polymeric materials was verified by using small molecules that constitute the same functionality as the model system. For example, diethyl malonate (1) and diethyl oxalate (2) are used as model compounds for acrylate polymers having malonate and oxalate side groups, respectively.

The electrochemical stability of these two model compounds was tested by cyclic voltammetry on a Pt button electrode, a Pt wire counter electrode and a quasi-reference electrode by immersion of 10mM AgNO in a glass tube filled with Vycor frit from an Ag wire₃Prepared in a 0.1M solution of tetrabutylammonium hexafluorophosphate. First, 0.1M lithium tetrafluoroborate (LiBF) in propylene carbonate₄) Calibrating the reference electrode in 10mM ferrocene solution to obtain E_ox(ferrocene/ferrocenium salt) ═ 0.058Vvs⁺). The same ferrocene solution was then used to calibrate the lithium reference electrode E_ox(ferrocene/ferrocenium salt) ═ 3.35-3.39V vs. Li/Li⁺). For the model compound, compound 1 and compound 2 were scanned at 0.1MLiBF at a scan rate of 5mV/s₄A 10 wt% solution in propylene carbonate was subjected to cyclic voltammetry. Then Li/Li⁺The cyclic voltammetry data was normalized to test its oxidative stability to lithium as these electrolyte materials interacted with the lithium anode in the actual cell. As shown in fig. 1, the electrochemical oxidation stability of both model compound 1 and compound 2 exceeded 4.5V, showing negligible current density response even at 4.5V. This clearly shows that these types of malonate and oxalate based structural systems, in particular poly (5-methylmalonyl amyl acrylate) and poly (5-methyloxalyl amyl acrylate) polymers, are stable at these high voltages and are promising candidates for high energy density lithium ion battery electrolytes.

Conductivity of acrylate dicarbonyl polymers

The ionic conductivity of various malonate and oxalate functionalized acrylate polymers was tested using LiTFSI as the source of lithium ions. To this end, two electrode symmetric cells were constructed by sandwiching a mixture of dicarbonyl acrylate polymer with various LiTFSI concentrations (i.e., 20, 30, and 40 wt%) between two aluminum electrodes. Then, the ionic conductivity of the polymer-LiTFSI electrolyte system was measured at 80 ℃ using impedance spectroscopy (table 2). Of the malonate pendant polyacrylates (items 1-4), the highest conductivity was seen in poly (5-methylmalonyl amyl acrylate) (item 4). The pendant polyacrylate group of the pendant oxalate group (item 5) showed only moderate conductivity.

TABLE 2

Lithium transport properties of acrylate dicarbonyl polymers

Cell design comprising acrylate dicarbonyl polymers

In one embodiment of the present invention, as shown in fig. 2, a lithium battery cell 200 has an anode 220 configured to absorb and release lithium ions. Anode 220 may be a lithium or lithium alloy foil or may be made of a material that absorbs lithium ions, such as graphite or silicon. Other options for anode 220 include, but are not limited to, lithium titanate and lithium silicon alloys. Lithium battery cell 200 also includes a cathode 240, which cathode 240 includes cathode active material particles 242, an electron conducting additive (not shown) such as carbon black, a current collector 244, a catholyte (electrolyte in the cathode) 246, and an optional binder (not shown). In one arrangement, the catholyte 246 comprises any of the acrylate-based polymer electrolytes disclosed above. In another arrangement, catholyte 246 comprises a mixture or combination of other solid polymer electrolytes with an acrylate-based polymer electrolyte. A separator region 260 is present between the anode 220 and the cathode 240. Catholyte 246 extends all the way into separator region 260 and facilitates lithium ion movement back and forth between anode 220 and cathode 240 as unit cell 200 cycles. The electrolyte 246 in the separator region 260 is the same as the catholyte 246 in the cathode 240.

In another embodiment of the present invention, as shown in fig. 3, the lithium battery cell 300 has an anode 320 configured to absorb and release lithium ions. Anode 320 may be a lithium or lithium alloy foil or may be made of a material that absorbs lithium ions, such as graphite or silicon. Other options for anode 320 include, but are not limited to, lithium titanate and lithium silicon alloys. The lithium battery cell 300 also includes a cathode 340, the cathode 340 including cathode active material particles 342, an electron conductive additive (not shown) such as carbon black, a current collector 344, a cathode electrolyte 346, and an optional binder (not shown). In one arrangement, catholyte 346 includes any of the acrylate-based polymer electrolytes disclosed above. In another arrangement, catholyte 346 comprises a mixture or combination of other solid polymer electrolytes with an acrylate-based polymer electrolyte. A separator electrolyte 360 is present between the anode 320 and the cathode 340. The separator electrolyte 360 facilitates lithium ions to move back and forth between the anode 320 and the cathode 340 as the unit cell 300 is cycled. The separator electrolyte 360 may comprise any electrolyte suitable for use in a lithium battery cell. In one arrangement, the separator electrolyte 360 comprises a liquid electrolyte that is immersed in a porous plastic material (not shown). In another arrangement, the separator electrolyte 360 comprises a viscous liquid electrolyte or a gel electrolyte. In another arrangement, the separator region 360 contains a solid polymer electrolyte in which the above-described acrylate-based polymer is immiscible.

In another embodiment of the present invention, a battery cell having a third configuration is described. Referring to fig. 4, the lithium battery cell 400 has an anode 420 configured to absorb and discharge lithium ions. Anode 420 may be a lithium or lithium alloy foil, or may be made of a material that absorbs lithium ions, such as graphite or silicon. Other options for anode 420 include, but are not limited to, lithium titanate and lithium silicon alloys. Lithium battery cell 400 also includes cathode 450, cathode 450 including cathode active material particles 452, an electronically conductive additive (not shown), current collector 454, catholyte 456, an optional binder (not shown), and capping layer 458. In one arrangement, the electrolyte in the cover layer 458 and the catholyte 456 are the same. In another arrangement, the electrolyte in the cover layer 458 and the catholyte 456 are different. Cover layer 458 and/or catholyte 456 may comprise a mixture or combination of any of the acrylate polymer electrolytes or other solid polymer electrolytes disclosed herein with an acrylate polymer electrolyte or electrolyte additive (in a solid polymer electrolyte matrix). In one arrangement, capping layer 458 is a solid electrolyte layer. There is a separator region 460 between the anode 420 and the cathode 450. The separator region 460 contains an electrolyte that facilitates the movement of lithium ions back and forth between the anode 420 and the cathode 450 as the unit cell 400 is cycled. The separator region may comprise any electrolyte suitable for use in a lithium battery cell. In one arrangement, the separator electrolyte 460 comprises a liquid electrolyte that is immersed in a porous plastic material (not shown). In another arrangement, separator electrolyte 460 comprises a viscous liquid electrolyte or a gel electrolyte. In another arrangement, the separator region 460 contains a solid polymer electrolyte in which the above-described acrylate-based polymer is immiscible.

The solid polymer electrolyte used in the separator region (e.g., separator region 360 or 460) can be any electrolyte suitable for Li batteries. Of course, many such electrolytes also include electrolyte salts that help provide ionic conductivity. Examples of useful lithium salts include, but are not limited to, LiPF₆、LiBF₄、LiN(CF₃SO₂)₂、Li(CF₃SO₂)₃C、LiN(SO₂CF₂CF₃)₂、LiB(C₂O₄)₂、Li₂B₁₂F_xH_12-x、Li₂B₁₂F₁₂LiTFSI, LiFSI, and mixtures thereof. Examples of such electrolytes include, but are not limited to, block copolymers comprising ion-conducting blocks and structural blocks that constitute the ion-conducting phase and the structural phase, respectively. The ionically conductive phase may comprise one or more linear polymers, such as polyethers, polyamines, polyimides, polyamides, polyalkylcarbonates, polynitriles, perfluoropolyethers, fluorocarbon polymers substituted with high dielectric constant groups (e.g., nitriles, carbonates, and sulfones), and combinations thereof. In one arrangement, the ions conductThe phases comprise one or more acrylate-based polymer electrolytes as disclosed herein. Linear polymers may also be used as graft copolymers in combination with polysiloxanes, polyalkoxysiloxanes, polyphosphazines, polyolefins and/or polydienes to form the conductive phase. The structural phase may be formed from materials such as polystyrene, hydrogenated polystyrene, polymethacrylate, poly (methyl methacrylate), polyvinylpyridine, polyvinylcyclohexane, polyimide, polyamide, polypropylene, polyolefin, poly (t-butyl vinyl ether), poly (cyclohexyl methacrylate), poly (cyclohexyl vinyl ether), poly (t-butyl vinyl ether), polyethylene, polyphenylene oxide, poly (2, 6-dimethyl-1, 4-phenylene ether), polyphenylene sulfide sulfone, polyphenylene sulfide ketone, polyphenylene sulfide amide, polysulfone, fluorocarbon compounds (e.g., polyvinylidene fluoride), or copolymers containing styrene, methacrylate, or vinylpyridine. It is particularly useful if the structural phase is rigid and is in a glassy or crystalline state.

For the embodiments described in fig. 2, 3, and 4, suitable cathode active materials include, but are not limited to, LFP (lithium iron phosphate), LMP (lithium-metal phosphate where the metal may be Mn, Co, or Ni), V₂O₅(vanadium pentoxide), NCA (lithium nickel cobalt aluminum oxide), NCM (lithium nickel cobalt manganese oxide), high energy NCM (HE-NCM-magnesium rich lithium nickel cobalt manganese oxide), lithium manganese spinel, lithium nickel manganese spinel, and combinations thereof. Suitable electron conducting additives include, but are not limited to, carbon black, graphite, vapor grown carbon fibers, graphene, carbon nanotubes, and combinations thereof. A binder may be used to hold the cathode active material particles and the electron conductive additive together. Suitable binders include, but are not limited to, PVDF (polyvinylidene fluoride), PVDF-HFP poly (vinylidene fluoride-co-hexafluoropropylene), PAN (polyacrylonitrile), PAA (polyacrylic acid), PEO (polyethylene oxide), CMC (carboxymethylcellulose), and SBR (styrene butadiene rubber).

Any of the polymers described herein may be liquid or solid, depending on their molecular weight. Any of the polymers described herein can be in a crosslinked state or an uncrosslinked state. Any of the polymers described herein may be crystalline or glassy. Any of the polymers described herein can be copolymerized with other polymers to form copolymers, block copolymers, or graft copolymers. Copolymerization may also affect the mechanical properties of certain polymers, making them solid polymer electrolytes. Any of the polymers described herein can be combined with an electrolyte salt to serve as a solid polymer electrolyte. Any of these solid polymer electrolytes may be used as a separator, a catholyte, an anolyte, or any combination thereof in a battery cell.

Examples of the invention

Details regarding the synthesis of the acrylate-based polymer according to the present invention are provided in the following examples. It should be understood that the following is representative only, and that the invention is not limited by the details set forth in this example.

Synthesis of poly (2-methylmalonylethylacrylate)

In one exemplary embodiment, poly (2-methylmalonylethylacrylate) is synthesized in two steps as described below.

Methylmalonyl chloride (4.8mL, 44.8mmol) was added to a solution of 2-hydroxyethyl acrylate (4.0g, 34.5mmol) and N-ethyldiisopropylamine (12.72g, 68.9mmol) in dichloromethane (15mL) under an argon atmosphere at ice bath temperature. The mixture was stirred at room temperature for 12 hours. The reaction mixture was diluted with ethyl acetate and washed with water. The organic phase was dried over magnesium sulfate, concentrated in vacuo, and the resulting crude product was purified by column chromatography to give 2-methylmalonyl ethyl acrylate (4.3g, 58%).

AIBN (0.046g, 0.28mmol) was added to a degassed solution of 2-methylmalonylethylacrylate (3g, 13.9mmol) in acetone (9.6mL) and then heated at 60 ℃ for 12 hours. The viscous polymerization mixture was then added dropwise to a large amount (100mL) of stirred methanol to obtain poly (2-methylmalonyl ethyl acrylate) as a highly viscoelastic colorless material (yield 2.5g, 83%). The following NMR characterization was obtained for poly (2-methylmalonylethylacrylate): 4.30-4.10(bd,4H),3.70(s,3H),3.50-3.40(bs,2H),2.30-2.25(bp,1H),1.9-1.40(m, 2H).

Synthesis of poly (5-methyloxalylpentyl acrylate)

In one exemplary embodiment, poly (5-methyloxalyl amyl acrylate) is synthesized in three steps as described below.

Acryloyl chloride (16.5mL, 216.0mmol) was added to a solution of 1, 5-pentanediol (25g, 240.4mmol) and N-ethyldiisopropylamine (88.8mL, 480.8mmol) in dichloromethane (100mL) under an argon atmosphere at ice bath temperature, and the mixture was stirred at room temperature for 12 hours. The reaction mixture was diluted with ethyl acetate and washed with water. The organic phase was dried over magnesium sulfate, concentrated in vacuo, and the resulting crude product was purified by column chromatography to give 5-hydroxypentyl acrylate (16.7g, 45%).

Methyloxalyl chloride (2.5mL, 26.6mmol) was added to a solution of 5-hydroxypentyl acrylate (3.5g, 22.1mmol) and N-ethyldiisopropylamine (4.6mL, 33.2mmol) in dichloromethane (25mL) under an argon atmosphere at ice bath temperature, and the mixture was stirred at room temperature for 12 hours. The reaction mixture was diluted with ethyl acetate and washed with water. The organic phase was dried over magnesium sulfate, concentrated in vacuo, and the resulting crude product was purified by column chromatography to give 5-methyloxalyl pentyl acrylate (4.6g, 85%).

AIBN (0.048g, 0.29mmol) was added to a degassed solution of 5-methyloxalylpentyl acrylate (3.6g, 14.7mmol) in acetone (5.0mL) and then heated at 65 ℃ for 5 hours. The viscous polymerization mixture was then added dropwise to a large volume (100mL) of stirred methanol to give poly (5-methyloxalyl amyl acrylate) as a highly viscoelastic colorless material (yield 2.5g, 83%). The following NMR characterization was obtained for poly (5-methyloxalylpentyl acrylate): 4.23(t,2H),4.10-3.90(bs,2H),3.83(s,3H),2.40-2.20(bp,1H),1.9-1.40(m, 8H).

The present invention has been described herein in considerable detail in order to provide those skilled in the art with information pertaining to the application of the novel principles and the configuration and use of such specialized components. It is to be understood, however, that the invention may be embodied in different equipment, materials, and devices, and that various modifications, both as to the equipment and operating procedures, may be accomplished without departing from the scope of the invention itself.