Modified photocurable PEEK photopolymer for 3D printing and preparations thereof

Abstract

The present invention relates to a novel photocurable acrylate PEEK (Polyether ether ketone) polymer with a modified chemical structure of formula I, useful in DLP (digital light processing) 3D printing. [Formula should be inserted here] wherein Ar is an aromatic unit, R is radical polymerizable unit, and x is in the range of 10 to 50.

Description

[0001] MODIFIED PHOTOCURABLE PEEK PHOTOPOLYMER FOR 3D PRINTING

[0002] AND PREPARATIONS THEREOF

[0003] TECHNICAL FIELD OF THE INVENTION:

[0004] The present invention relates to novel photocurable acrylate PEEK (Polyether ether ketone) polymer with a modified chemical structure of formula I, useful in DLP (digital light processing) 3D printing.

[0005] Formula-I wherein Ar is an aromatic unit, R is radical polymerizable unit, and x is in the range of 10-50.

[0006] BACKGROUND AND PRIOR ARTS OF THE INVENTION:

[0007] With continued research and the development of new materials, the field of additive manufacturing (3D printing) is constantly growing. The production of prototypes or final products with intricate designs and high-performance attributes using additive manufacturing (AM) is a subject of considerable interest, aiming to match the qualities of molded or injection-molded high-performance polymers (HPPs). Many AM techniques for high- performance polymers (HPPs) have integrated strategies to surmount these challenges.

[0008] The commercially available PEEK polymers possess high mechanical strength and high Tg values, hence, for 3D printing or any other application, they require higher temperature ranges e.g. more than 350 °C. This higher temperature requirement limits available PEEK polymer in 3D printing such as DLP printing technique.

[0009] It is nowhere reported or suggested in the literature that the PEEK or any modified PEEK can be used in DLP 3D printing. Also, commercially available PEEK have only been used in other printing techniques such as Fused deposition modeling (FDM), also known as fused filament fabrication (FFF), which is done at higher temperature, and the same are not suitable for DLP printing technique. J Mater Sci: Mater Med 2014, 25, 2027-2039 reports modified PEEK (acrylate PEEK) along with other commercial acrylates to form a formulation, which was UV cured by pouring into a quartz mold to form IOL (intraocular lens). The general structure is a PEEK-based repeat unit and polymerizable methacrylate in the terminal unit linked by urethane linkage.

[0010] ACS Macro Lett. 2020, 9, 1119-1129, is related to photo-curable PEEK polymer chemistry. Although the structure is different, it relates to both photo curable methacrylate terminal groups as well as urethane linkage in the backbone. However, work related to photo-curable PEEK polymer synthesis and DLP 3D printing is not provided.

[0011] Additive Manufacturing 2019, 28, 430-438, discusses the parameters of fused deposition modeling (FDM) technology used in finished parts made from polyether ether ketone (PEEK) and also the possibility of printing small PEEK pails.

[0012] Hence, a need still exists for a polymer (PEEK) that is suitable for Digital Light Processing (DLP) 3D printing at room temperature.

[0013] Inventors of the present invention envisioned a modified PEEK polymer which can be cured by light-based 3D printing, where temperature is not a critical requirement with sustained mechanical properties in order to be useful in DLP based 3D printing technique.

[0014] Based on the above it is desired to address the above-mentioned disadvantages or other shortcomings or at least provide useful alternative.

[0015] OBJECTIVES OF THE INVENTION:

[0016] An objective of the present invention is to provide a novel photocurable acrylate PEEK (polyether ether ketone) polymer with a modified chemical structure of formula I.

[0017] Another objective of the invention is to provide a process for the preparation of photocurable acrylate PEEK (polyether ether ketone) polymer with a modified chemical structure of formula I.

[0018] Yet another objective of the invention is to provide novel photocurable PEEK polymers that are better or improved than the PEEKs reported in the literature in terms of 3D printing, ease of use, selectivity towards formation of product, lesser warpage, higher resolution 3d printed products, etc.

[0019] Yet another objective of the invention is to provide novel photocurable PEEK polymers for application in the field of aerospace, medicine, automotive, robotics, and machinery

[0020] Yet another objective of the invention is to provide a composition comprising effective amount of polymer or mixture of polymers, photocurable acrylated PEEK polymer of formula I and a photoinitiator

[0021] Still another objective of the invention is to provide a process for preparation of 3D printable composition comprising effective amount of polymer or mixture of polymers, photocurable acrylated PEEK polymer of formula I and a photoinitiator.

[0022] SUMMARY OF THE INVENTION:

[0023] The present invention relates to novel photocurable acrylate PEEK (polyether ether ketone) polymer with a modified chemical structure of formula I, useful in DLP (digital light processing) 3D printing.

[0024] Formula-I wherein,

[0025] Ar is an aromatic unit,

[0026] R is radical polymerizable unit, and x is in the range of 10-50.

[0027] In some embodiments, a process for preparation of photocurable acrylated PEEK polymer of formula I is provided.

[0028] In some embodiments, composition comprising effective amount of polymer or mixture of polymers, photocurable acrylated PEEK polymer of formula I and photoinitiator is provided. In some embodiments, a process for preparation of 3D printable composition comprising effective amount of polymer or mixture of polymers, photocurable acrylated PEEK polymer of formula I and a photoinitiator is provided.

[0029] BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 shows the viscosity of all resin compositions i.e., compositions containing different amounts of photocurable acrylated PEEK polymer of formula I.

[0031] Figures 2 (a-e) shows DSC graphs of all resin formulations containing different amounts of photocurable acrylated PEEK polymer of formula I.

[0032] Figure 3a illustrates images with different complex 3D printed products.

[0033] Figure 3b highlights the low warpage problem.

[0034] Figures 4a-4c illustrates the evaluation of different properties i.e., Tensile strength, TGA, and DSC graphs of the PEEK polymers.

[0035] DETAILED DESCRIPTION OF THE INVENTION

[0036] In an embodiment, the present invention relates to a photocurable acrylate PEEK (polyether ether ketone) polymer having a chemical structure of formula I, the formula I is represented by:

[0037] Formula-I wherein

[0038] Ar is an aromatic unit,

[0039] R is a radical polymerizable unit, and x is in the range of 10-50.

[0040] In an embodiment, the x is in the range of 20-50. In another embodiment, the Ar being the aromatic unit is selected from the group consisting of:

[0041] -(CH2)n-NH2-, and -(CH2)n-COO-; X is (meth)acrylate or urethane acrylate; and n is in the range of 2-6.

[0042] In another embodiment, the R being the radical polymerizable unit is selected from the group consisting of:

[0043] The dashed or crossing bonds indicated in the R and Ar are provided to show the connection of bonds as shown in the Markush structure of formula I. In another embodiment, the photocurable acrylate PEEK (polyether ether ketone) polymer is selected from the group comprising of:

[0044] Polymer 4 Polymer 5, where n is in the range of

[0045] 10-50, and Polymer 6, wherein n is in the range of 10-50.

[0046] In some embodiments, polymerizable group(s) (R) is / are introduced into every repeating unit.

[0047] In another embodiment, the present invention provides a process for the preparation of the photocurable acrylate PEEK (polyether ether ketone) polymer having a chemical structure of formula I, the formula I is represented by: Formula-I wherein

[0048] Ar is an aromatic unit,

[0049] R is a radical polymerizable unit, and x is in the range of 10-50; the process comprising steps of: a) preparing a mixture comprising at least two aromatic (Ar) precursors, a base, a reaction medium and a 1stsolvent; b) reacting and refluxing the mixture of step a) under stirring at temperature in the range of 120-140 °C for time period in the range of 2-4 h followed by increasing the temperature to 170-190 °C to remove water and the 1stsolvent, and to obtain intermediate PEEK polymer compound of formula II Formula 11; wherein Ar and x is same as defined above; c) reacting the crude intermediate PEEK polymer compound of formula II of b) with a radical polymerizable unit containing precursor solution at temperature in the range of 30-35 °C for time period in the range of 2-4 h to obtain the photocurable acrylate PEEK polymer of formula I; and d) optionally precipitating, washing and drying the photocurable acrylate PEEK polymer of formula I of c) to obtain pure photocurable acrylate PEEK polymer of formula I.

[0050] In an embodiment, the x is in the range of 20-50.

[0051] In another embodiment, the at least two aromatic (Ar) precursors are selected from the group comprising of combination of any two of Bisphenol A, 4,4’ -difluoro benzophenone, 3- pentadecyl 4,4'-biphenol, phenolphthalein, 4,4'-((3-methoxyphenyl)methylene)bis(2- methoxyphenol) (DMBM), 4,4-Bis(4-hydroxyphenyl)valeric acid, and so on. In another embodiment, the base is selected from the group comprising of potassium carbonate, calcium carbonate, sodium carbonate, triethylamine, potassium bicarbonate, and so on.

[0052] In another embodiment, the reaction medium is selected from the group comprising of dimethyl acetamide, toluene, and so on.

[0053] In another embodiment, the 1stsolvent is selected from the group comprising of toluene, dimethyl acetamide, and so on.

[0054] In another embodiment, the weight ratio of the reaction medium: 1stsolvent is in the range of 0.5-1.5: 0.5-1.5.

[0055] In another embodiment, the weight ratio of the reaction medium: 1stsolvent is 1:1.

[0056] In another embodiment, the removal of water and the 1stsolvent in step b) is done by azeotropic distillation.

[0057] In another embodiment, the radical polymerizable unit containing precursor solution is prepared by dissolving a radical polymerizable unit containing precursor in a solvent, wherein the solvent is selected from the group comprising of toluene, dimethyl acetamide, and so on.

[0058] In another embodiment, the radical polymerizable unit containing precursor is selected from the group comprising of 2 -hydroxyethyl 4-fluoro benzoate, acryloyl chloride, PEEK Polymer and so on.

[0059] In another embodiment, the precipitation of d) is done by pouring undissolved or dissolved photocurable acrylate PEEK polymer of formula I of step c) in a methanol, ethanol, chloroform, or dimethylsulfoxide (DMSO) followed by filtering to obtain the precipitate, wherein the dissolved PEEK of formula I is obtained by dissolving in a chloroform.

[0060] In another embodiment, the washing of precipitate obtained after precipitation using water at least 2 times to remove the salt and impurities.

[0061] In another embodiment, the precipitation and washing can be done more than one time i.e., 2 or 3 times. In another embodiment, the drying of step d) is done in a vacuum at temperature in the range of 45-60 C for time period in the range of 22-26 h.

[0062] In another embodiment, the present invention provides a process for the preparation of the photocurable acrylate PEEK (polyether ether ketone) polymer having a chemical structure of formula I, the formula I is represented by:

[0063] Formula-I wherein

[0064] Ar is an aromatic unit,

[0065] R is a radical polymerizable unit, and x is in the range of 10-50; the process comprising steps of: a) preparing a mixture comprising at least two aromatic (Ar) precursors and a base in presence of a reaction medium and a 1stsolvent; b) reacting and refluxing the mixture of step a) under stirring at temperature in the range of 120-140 °C for time period in the range of 2-4 h followed by increasing the temperature to 170-190 °C to remove water and the 1stsolvent, and to obtain intermediate PEEK polymer compound of formula II Formula II; wherein Ar and x is same as defined above; c) preparing a solution of the intermediate PEEK polymer compound of formula II of b) by dissolving in a 2ndsolvent and mixing with a catalyst; d) dropwise adding a radical polymerizable unit containing precursor solution with the crude intermediate PEEK polymer compound of formula II solution containing catalyst of c) for time period in the range of 25-35 minutes to obtain a reaction mixture; e) mixing the reaction mixture of d) under stirring at temperature in the range of 20- 35 °C for time period in the range of 1.5 -2.5 h followed by stirring at temperature in the range of 25-35 °C for time period in the range of 11-13 h to obtain the photocurable acrylate PEEK polymer of formula I; and f) optionally precipitating, washing and drying the photocurable acrylate PEEK polymer of formula I of e) to obtain pure phs otocurable acrylate PEEK polymer of formula I.

[0066] In an embodiment, the x is in the range of 20-50.

[0067] In another embodiment, the at least two aromatic (Ar) precursors are selected from the group comprising of combination of any two of Bisphenol A, 4,4’ -difluoro benzophenone, 3- pentadecyl 4,4 '-biphenol, phenolphthalein 4,4'-((3-methoxyphenyl)methylene)bis(2- methoxyphenol) (DMBM), 4,4-Bis(4-hydroxyphenyl)valeric acid, and so on.

[0068] In another embodiment, the base is selected from the group comprising of potassium carbonate, calcium carbonate, sodium carbonate, triethylamine, potassium bicarbonate, and so on.

[0069] In another embodiment, the reaction medium is selected from the group comprising of dimethyl acetamide, NMP, and so on.

[0070] In another embodiment, the 1stsolvent is selected from the group comprising of toluene, dimethyl acetamide, and so on.

[0071] In another embodiment, the weight ratio of the reaction medium: 1stsolvent is in the range of 0.5-1.5: 0.5-1.5.

[0072] In another embodiment, the weight ratio of the reaction medium: 1stsolvent is 1:1. In another embodiment, the removal of water and the 1stsolvent in step b) is done by azeotropic distillation.

[0073] In another embodiment, the 2ndsolvent is selected from the group comprising of dimethyl formamide (DMF), DCM, and so on.

[0074] In another embodiment, the catalyst is selected from the group comprising of dibutyltindilaurate (DBTDL), Lewis acid catalyst, and so on.

[0075] In another embodiment, the radical polymerizable unit containing precursor solution is prepared by dissolving a radical polymerizable unit containing precursor in a solvent, wherein the solvent is selected from the group comprising of DMF, DCM, and so on.

[0076] In another embodiment, the radical polymerizable unit containing precursor is selected from the group comprising of 2-isocyanatoethyl methacrylate, acryloyl chloride, and so on.

[0077] In another embodiment, the precipitation of f) is done by pouring undissolved or dissolved photocurable acrylate PEEK polymer of formula I of step c) in a methanol, ethanol, chloroform, or dimethyl sulfoxide (DMSO) followed by filtering to obtain the precipitate, wherein the dissolved PEEK of formula I is obtained by dissolving in a chloroform.

[0078] In another embodiment, the washing of precipitate obtained after precipitation using water at least 2 times to remove the salt and impurities.

[0079] In another embodiment, the precipitation and washing can be done more than one time i.e., 2 or 3 times.

[0080] In another embodiment, the drying of step f) is done in a vacuum at temperature in the range of 25-35°C for time period in the range of 22-26 h.

[0081] In another embodiment, a polymer composition for 3D printing, comprising an effective amount of: i. polymer, ii. the photocurable acrylated PEEK polymer of formula I, and iii. a photoinitiator.

[0082] In some embodiments, the polymer of formula I disclosed herein acts as crosslinker in said polymer composition for 3D printing.

[0083] In some embodiments, the polymer of formula I acts as crosslinker depending upon the miscibility of the polymer with the diluents i.e., the polymer or mixture of polymers.

[0084] In some embodiments, the polymer is selected from Tricyclo[5.2.1.02,6]decane-dimethanol diacrylate (TCDDA), Bisphenol A ethoxylate dimethacrylate (BPAEDMA), Isobornyl methacrylate, and Tris(2-Hydroxyethyl) Isocyanurate Triacrylate or any combination thereof.

[0085] In some embodiments, the photoinitiator is selected from (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), 2-hydroxy 2-methylpropiophenone, bisacylphosphine oxide (BAPO), benzoyl peroxide, and so on.

[0086] In another embodiment, the weight % of the photocurable acrylated PEEK polymer of formula I is in the range of 5-15 %.

[0087] In another embodiment, the weight % of the photoinitiator is in the range of 0.5- 1.5 %.

[0088] In another embodiment, the weight % of the polymer is to make 100 % of the composition.

[0089] In another embodiment, the weight % of the polymer is in the range of 83.5-94.5 %.

[0090] In another embodiment, the weight % of the photocurable acrylated PEEK polymer of formula I is in the range of 5-15 %, weight % of the photoinitiator is in the range of 0.5-1.5 %, and rest is the polymer to make 100 % of the composition.

[0091] In specific embodiment, the weight % of the photocurable acrylated PEEK polymer of formula I is in the range of 5-10 %.

[0092] In specific embodiment, the weight % of the photoinitiator is in the range of 0.9- 1.1 %. In some embodiments, a process for preparation of 3D printable composition comprising effective amount of polymer or mixture of polymers, photocurable acrylated PEEK polymer of formula I and a photoinitiator is provided.

[0093] In some embodiments, the composition is 3D printed by a method known as DLP (digital light processing) where ingredient(s) are in liquid state while printing, and preferably done at room temperature (25-35 °C) or lesser temperature (15-25 °C).

[0094] For Digital Light Processing (DLP) 3D printing at room temperature, four different resins were prepared based on novel cross -linkable acrylate PEEK polymers with two acrylate diluents. Modified PEEK polymers were successfully utilized for room-temperature DLP 3D printing with minimum equipment demand and minimal waste generation. The minimum weight percentage of the synthesized acrylate PEEK polymer is sufficient to enhance the mechanical properties of the 3D-printed parts.

[0095] EXAMPLES

[0096] Following examples are given by way of illustration therefore should not be construed to limit the scope of the invention.

[0097] Materials used:

[0098] 4,4 '-difluoro benzophenone, l,3-bis(4-fluorobenzoyl)benzene, 4-fluro benzoic acid and dibutyltin dilaurate (DBTDL), 3-Pentadecyl phenol, N-bromosuccinimide, 4-methoxy phenyl boronic acid, tetrakis(triphenylphosphine)palladium and calcium hydride were purchased from Aldrich and purified by recrystallization from toluene before use. Bromo ethanol, Methacryloyloxyethyl isocyanate, Tricyclo[5.2.1.02,6]decanedimethanol diacrylate (TCDDA), 3 -Pentadecyl phenol, 4-methoxy phenyl boronic acid, tetrakis(triphenyl phosphine) palladium and, Bisphenol A ethoxylate dimethacrylate (BPAEDMA) were purchased from TCI chemical and used as such. Potassium carbonate, dimethyl sulfate, N- bromosuccinimide, and boron tribromide were purchased from local chemical vendors. Tetrahydrofuran (THF), chloroform, methanol, isopropyl alcohol, dichloromethane, hexane, and sodium sulfate (anhydrous) were purchased locally. For gel permeation chromatography HPLC-grade THF was purchased from Merck Chemicals (India). Example 1: Synthesis of 2-hydroxy ethyl 4-fluoro benzoate (radical polymerizable unit containing precursor or compound):

[0099] 4-fluoro benzoic acid (5 g, 35.7 mmol) and Bromo ethanol (5.8 g, 46.4) were taken in a twonecked round bottom flask equipped with a magnetic stirring bar. 150 ml of acetonitrile was added to the reaction mixture and stirred for 10 minutes. N, N-Diisopropylethylamine (5.5 g, 42.84 mmol) was added to the reaction and immersed into a pre-heated oil bath at 75 °C for 12 h. After that, remove the reaction mixture from oil bath cool it to room temperature, and remove the solvent with the aid of a rotary evaporator. Finally, the crude residue was dissolved in ethyl acetate and washed with 1 M HC1 solution three times, saturated NaHCOs three times, and brine solution. The organic part was dried over sodium sulfate and the solvent was evaporated in a rotary evaporator. Yield 78 %. ’ H NMR spectrum (400 MHz, CDC13) 6 in ppm: 8.05 (d, 2H), 7.11 (d, 2H), 4.44 (d, 2H), 3.94 (d, 2H), 2.16 (s, 1H).13C NMR (100 MHz, CDCI3) 6 in ppm: 165.65, 164.29, 131.97, 125.77, 115.14, 66.41, 61.02

[0100] Example 2: Synthesis of end cap PEEK (Polymer 1):

[0101] Bisphenol A (3.45 g, 15.1 mmol), 4,4’-difluoro benzophenone (3 g, 13.7 mmol), and potassium carbonate (4.6 g, 33.2 mmol) were taken in a three-necked round bottom flask equipped with a reflux condenser, Dean-Stark trap, and magnetic stirring bar at nitrogen atmosphere. 20 ml of Dimethyl acetamide and 20 ml of toluene were added to the reaction mixture and immersed into the pre-heated oil bath at 130 °C for 3 h. After that, the temperature was raised to 180 °C to remove water and toluene by azeotropic distillation and the reaction was continued for another 3 h. Subsequently, a solution of 2-hydroxyethyl 4- fluoro benzoate (1.26 g, 6.8 mmol) in toluene was added to the reaction mixture and the reaction was continued for another 3 h. After cooling, the obtained viscous reaction mixture was poured into the methanol to precipitate the polymer filtered, and washed with water 2-3 times to remove the salt. Again dissolved in chloroform precipitated in methanol, filtered, and dried under a vacuum at 50 °C for 24 h. Yield 80 %. ’ H NMR spectrum (400 MHz, CDCI3) 6 in ppm: 8.04 (d, 4H), 7.77-7.78 (m, 193H), 7.25-7.29 (m, 222H), 6.98-7.05 (m, 407H), 4.43- 4.48 (m, 4H), 3.95-3.98 (m, 4H), and 1.72 (m, 293H).13C NMR (100 MHz, CDCI3) 6 in ppm: 186.18, 161.43, 153.49, 146.73, 132.19, 128.33, 119.53, 117.16, 66.92, 60.93, 42.37, 31.01.

[0102] Example 3: Synthesis of end cap Modified PEEK (Polymer 2):

[0103] 3-pentadecyl 4,4'-biphenol was synthesized according to the literature report. 3-pentadecyl 4,4'-biphenol (2.99 g, 7.56 mmol), 4,4’-difluoro benzophenone (1.5 g, 6.87 mmol), and potassium carbonate (2.3 g, 16.6 mmol) were taken in a three-necked round bottom flask equipped with a reflux condenser, Dean-Stark trap, and magnetic stirring bar at nitrogen atmosphere. 15 ml of Dimethyl acetamide and 15 ml of toluene were added to the reaction mixture and immersed into the pre-heated oil bath at 130 °C for 3 h. After that, the temperature was raised to 180 °C to remove water and toluene by azeotropic distillation and the reaction was continued for another 8 h. After that, a solution of 2-hydroxyethyl 4-fluoro benzoate (1.26 g, 6.8 mmol) in toluene was added to the reaction mixture and the reaction was continued for another 3 h. After cooling, the obtained viscous reaction mixture was poured into the methanol to precipitate the polymer and decant the methanol, and washed with water 2-3 times to remove the salt. Again dissolved in chloroform precipitated in methanol, and dried under a vacuum at 50 °C for 24 h. Yield 75%. ’ H NMR spectrum (400 MHz, CDCI3) 6 in ppm: 8.08 (d, 4H), 7.84-7.88 (m, BOH), 7.37 (m, 68H), 6.95-7.09 (m, 313H), 4.47 (m, 4H), 3.98 (m, 4H), 2.59 (m, 65H), 1.23-1.49 (m, 960H), 0.87 (m, 118H).13C NMR (100 MHz, CDCI3) 6 in ppm: 194.29, 191.31, 161.25, 154.72, 142.82, 137.52, 132.28, 130.97, 119.59, 117.41, 70.29, 65.19, 33.16, 31.92, 29.69, 22.69, 14.13.

[0104] Example 4: Synthesis of urethane acrylate PEEK (UMPEEK) (Polymer 3):

[0105] PEEK polymer (8000 g / mol, 0.25 mmol) was dissolved in 30 ml of dry dimethyl formamide in a 50 ml two-necked round bottom flask under a nitrogen atmosphere and cooled under an ice bath. Two drops of dibutyltindilaurate (DBTDL) were added as a catalyst followed by dropwise addition of 2-isocyanatoethyl methacrylate (465 mg, 3 mmol) in 2 ml of dry DMF within 30 minutes of time period. The reaction was stirred at cold conditions for 2 h and further left for 12 h at room temperature. After that, reaction was poured into the methanol to precipitate acrylate PEEK polymer and filtered. Again, polymer was dissolved in chloroform and reprecipitated in methanol 2-3 times to completely remove of unreacted product. The white power polymer dried in vacuum at room temperature for 24 h. Yield 75 %. ’ H NMR spectrum (400 MHz, CDCI3) 6 in ppm: 8.04 (d, 4H), 7.82 (m, 203H), 7.25-7.27 (m, 240H), 6.98 (m, 424H). 6.11 (s, 2H), 5.57 (s, 2H), 4.47 (m, 8H), 4.24 (m, 8H), 2.04 (s, 6H), 1.67 (m, 288H).13C NMR (100 MHz, CDCI3) 6 in ppm: 194.32, 161.46, 153.47, 146.75, 132.23, 128.35, 119.56, 117.16, 66.61, 61.54, 42.38, 31.03.

[0106] Table 2: Molecular weight and PDI of modified PEEK polymers

[0107] Example 5: Synthesis of urethane acrylate Modified PEEK (UMmPEEK) (Polymer 4):

[0108] A similar procedure was followed for the synthesis of urethane acrylate -modified PEEK polymer. Modified PEEK (18400 g / mol, 0.11 mmol) was dissolved in 30 ml of dry DMF and Two drops of DBTDL were added at the nitrogen atmosphere. 2-isocyanatoethyl methacrylate (202 mg, 1.3 mmol) in 2 ml of dry DMF was added to the polymer solution within 30 minutes of time period under ice-cold conditions. The reaction was stirred at cold conditions for 2 h and further left for 12 h at room temperature. After that, the reaction was poured into the methanol to precipitate the acrylate PEEK polymer and decant the methanol. Dissolved in chloroform and reprecipitated in methanol 2-3 times to remove the unreacted product. The semi-solid polymer dried in vacuum at room temperature for 24 h. Yield 75 %.

[0109] ’ H NMR spectrum (400 MHz, CDC13) 6 in ppm: 8.05 (d, 4H), 7.84 (m, 121H), 6.98-7.33 (m, 392H), 6.12 (s, 2H), 5.59 (s, 2H), 4.48 (m, 8H), 4.22 (m, 8H), 2.59 (m, 64H), 2.20 (s, 6H), 1.49-1.63 (m, 165H), 1.23 (m, 828H), 0.87 (m, 122H).13C NMR (100 MHz, CDCI3) 6 in ppm: 194.27, 187.86, 161.25, 154.90, 142.82, 137.33, 132.28, 131.56, 130.97, 120.60, 119.59, 117.25, 70.29, 65.19, 31.92, 29.35, 22.69, 18.31, 14.12.

[0110] Table 3: Molecular weight and PDI of modified PEEK polymers

[0111] Example 6: Synthesis of phenolphthalein Polyether Ether Ether Ketone (Ph-PEEK) where x is in the range of 12-42.

[0112] A representative procedure for the synthesis of polyether ether ketone (PEEK) is as follows. 100 mL three-necked round bottom flask was fitted with a reflux condenser, a magnetic stirring bar, and a Dean-stark trap. Phenolphthalein (802 mg, 2.52 mmol), 4,4- Difluorobenzophenone (500 mg, 2.29 mmol), and K2CO3 (731.4 mg, 5.29 mmol) were taken into the rb under nitrogen atmosphere followed by addition of N, N dimethylacetamide (10 mL), and Toluene (10 mL) as a mixture of solvent. After that, the reaction mixture was heated at 130 °C for 3 h and the formed water was removed by azeotropic distillation with toluene. Then the reaction temperature was raised to 180 °C for 8 h. 2-hydroxyethyl 4- fluoro benzoate (464 mg, 2.52 mmol) was added to the reaction dissolving in N, N dimethylacetamide and again heated the reaction at 180 °C for 3 h. After that, the reaction was stopped and cooled to room temperature. The obtained viscous reaction mixture was precipitated into 200 mL cold water and stirred to remove the salt from the polymer. The polymer was filtered and dissolved in chloroform and reprecipitated in the cold methanol three times. Finally, the polymer was dried under a vacuum at 50 °C for 48 h. ’ H NMR spectrum (400 MHz, CDCI3) 6 in ppm: 7.97-7.99 (d,lH), 8.05-8.03 (d,4H), 6.90-6.97 (d,4H), 7.78-7.80 (d,4H) 7.55-7.61 (t,lH), 7.37 (d,4H), 7.39 (d,4H), 7.03-7.06 (d,4H), 6.85-6.90 (t,lH), 3.95-3.97 (t,4H), 4.09-4.46 (t,4H) 7.03-7.06 (t,lH), 6.97-7(d,lH).13C NMR (100 MHz, CDCI3) 6 in ppm: 193.72, 169.09, 160.21, 158.52, 155.82, 151.44, 136.26, 134.05, 132.35, 131.90, 129.30, 128.62, 125.90, 123.65, 119.25, 117.43,117.34, 114.13, 113.75, 90.59, 68.30, 60.98.

[0113] Example 7: Synthesis of Urethane Acrylate Ph-PEEK Polymer: where x is in the range of 12-32.

[0114] A similar procedure was followed for the synthesis of urethane acrylate Ph-PEEK polymer. Ph-PEEK (9800 g / mol, 0.96 mmol) was dissolved in 30 ml of dry DMF and Two drops of DBTDL were added at the nitrogen atmosphere. 2-isocyanatoethyl methacrylate (512 mg, 3.30 mmol) in 2 ml of dry DMF was added to the polymer solution within 30 minutes of time period under ice-cold conditions. The reaction was stirred at cold conditions for 2 h and further left for 12 h at room temperature. After that, the reaction was poured into the methanol to precipitate the acrylate PEEK polymer and decant the methanol. Dissolved in chloroform and reprecipitated in methanol 2-3 times to remove unreacted product. The semisolid polymer dried in vacuum at room temperature for 24 h.1H NMR spectrum (400 MHz, CDC13) 6 in ppm: 7.97-7.99 (d,lH), 8.01 (d, 4H), 6.99 (d,4H), 7.78-7.80 (d,4H)) 7.51-7.61 (t,lH), 7.37 (d,4H) 7.39 (d,4H) 7.03-7.06 (d,4H), 6.87-6.96 (t,lH), 3.51-3.53 (d,4H), 4.22-5 (6H,m), 1.93 (s,6H).13C NMR (100 MHz, CDCI3) 6 in ppm: 194.05, 169.41, 167.46, 160.64, 160.53, 156.13, 155.94, 151.75, 136.96, 136.58, 134.36, 132.22, 128.94, 126.23, 123.97, 119.57, 117.74, 117.66, 114.43, 114.06, 91.17, 90.91, 64.12, 63.57, 40.21, 39.66, 18.26.

[0115] Example 8: Synthesis of Ph-OH PEEK Polymer: where x is in the range of 12-32.

[0116] Ph-OH (0.91 g, 2.52 mmol), 4,4’ -difluoro benzophenone (0.5 g, 2.29 mmol), and potassium carbonate (0.66 g, 4.80 mmol) were taken in a three-necked round bottom flask equipped with a reflux condenser, Dean-Stark trap, and magnetic stirring bar at nitrogen atmosphere. 10 ml of Dimethyl acetamide and 10 ml of toluene were added to the reaction mixture and immersed into the pre-heated oil bath at 130 °C for 3 h. After that, the temperature was raised to 180 °C to remove water and toluene by azeotropic distillation and the reaction was continued for another 6 h. After cooling, the obtained viscous reaction mixture was poured into the methanol to precipitate the polymer filtered, and washed with water 2-3 times to remove the salt. Again, dissolved in chloroform precipitated in methanol, filtered, and dried under a vacuum at 50 °C for 24 h. ’ H NMR spectrum (400 MHz, CDCh) 6 in ppm:7.89-7.91 (d,lH), 7.79-7.81 (d,4H), 7.32-7.33 (t, 1H), 7.49 (t,lH), 6.82-6.84 (d,lH), 7.25 (d,4H), 7.04 (d,4H), 7.06 (d,4H), 3.94 (s,lH), 3.65-3.66 (t,2H) 3.33-3.34 (t,2H).13C NMR (100 MHz, CDCh) 6 in ppm: 170.72, 166.45, 160.74, 156.46, 150.91, 135.75, 133.08, 132.62, 130.07, 129.05, 124.34, 123.78, 120.17,118.19, 75.82, 69.97, 62.16, 45.62.

[0117] Example 9: Synthesis of Ph-OH PEEK Acrylation (Ph-OH PEEK Acy): where x is in the range of 12-32.

[0118] A similar procedure was followed for the synthesis of acrylation of Ph-OH PEEK polymer. Ph-OH PEEK pepeating unit ( 0.5, 0.85 mmol) was dissolved in 20 ml of dry DMF and Two drops of DBTDL were added at the nitrogen atmosphere. 2-isocyanatoethyl methacrylate (145.70 mg, 0.93 mmol) in 10 ml of dry DMF was added to the polymer solution within 30 minutes of time period under ice-cold conditions. The reaction was stirred at cold conditions for 2 h and further left for 12 h at room temperature. After that, the reaction was poured into the methanol to precipitate the acrylate PEEK polymer and decant the methanol. Dissolved in chloroform and reprecipitated in methanol 2-3 times to remove the unreacted product. The semi-solid polymer dried in vacuum at room temperature for 24 h.1H NMR spectrum (400

[0119] MHz, CDCh) 6 in ppm: 7.89-7.91 (d,lH), 7.79-7.81 (d,4H), 7.28-7.34 (t,lH), 7.48 (t,lH), 6.82-6.84 (d,lH), 7.07 (d,4H), 7.04 (d,4H), 7.06 (d,4H), 4.14-4.16 (t,2H), 3.66-3.77 (t,2H), 3.39-3.40 (t,2H), 3.58 (t,2H), 5.54 (d,lH), 6.07 (d,lH), 1.90 (s,3H).

[0120] Example 10: Formulation of different Resins (Polymer compositions): The PEEKAc resin formulations for 3D printing were prepared by mixing different weight percentages of allyl PEEKAc and mPEEKAc (UMmPEEK) polymer with Tricyclo[5.2.1.02,6]decanedimethanol diacrylate (TCDDA) and Bisphenol A ethoxylate dimethacrylate (BPAEDMA). The TPO photoinitiator weight percentage was examined from the photo DSC kinetic experiment. No organic solvent was added to the 3D printing resin formulation. Considering that the photoinitiator is sensitive to visible light, the glass vial was completely wrapped with a layer of aluminum foil to prevent any pre -polymerization. All resin formulations were prepared following a similar procedure

[0121] Reactive diluents fused or PEEK polymer resin formulations for DLP 3D printing

[0122] Table 4. The different weight percentages of PEEK polymer, a reactive diluent, and TPO photo initiator.

[0123] The Ref (reference) is a mixture of TCDDA and BPAEDMA small acrylate. The synthesized PEEKAc and mPEEKAcpolymer were mixed into it with different weight percentages.

[0124] Analysis of the prepared polymer compositions:

[0125] 1. Method of viscosity measurement:

[0126] Viscosity analysis of the resin formulations was conducted using Rotational Parallel Plate measurements. The Anton Paar Physica Modular Compact Rheometer (MCR) 301 equipped with a cup and bob was employed for the experiment. The resin formulation, excluding any photoinitiator, was poured carefully into the cup up to a specified mark. Subsequently, the bob was inserted into the resin, and shear was induced by rotating it. The experiment involved systematically increasing the shear rate from 1 to 1000 per second to measure viscosity, expressed in Pascal- seconds (Pa-s). The resin's temperature was maintained at a constant 30 °C throughout the experiment. The rheology of the resin formulation was measured using the same instrumentation, with a constant angular frequency of 1 rad / s, and the strain was varied from 0.1 to 10. The viscosity of the resin formulations was measured and observed there was no significant change in the viscosity of the resin formulation.

[0127] 2. Mechanical &Thermal Studies of the prepared polymers:

[0128] Method of measurement: The 3D printed component underwent tensile strength analysis using the Instron series 33R4204 Universal Testing Machine, featuring a 1 KN capacity load cell, at room temperature. ASTM D638 type V specimens were utilized for the tensile test, with an average of five samples tested to ensure result accuracy and consistency. Each sample had a 10 mm gauge length, and the experiment involved a stretching rate of 5 mm per minute. Mechanical properties such as tensile strength, Young's modulus, elongation, and toughness were determined at the point of sample breakage.

[0129] Table 5

[0130] 3. Warpage Analysis:

[0131] Figure 3a shows the thicker 3D printed products / parts using the using the UMPEEK (polymer 3) and UMmPEEK (polymer 4) resin formulation without or negligible warpage. Figure 3b shows the thinner 3D-printed parts using the UMPEEK / PEEK (polymer 3) and mPEEK or UMmPEEK (polymer 4) resin formulation, where the polymer 4 based formulation shows relatively zero or negligible warpage considering a precisely flat structure according to the resin validation Xp2 Standard Triangle Language, even after a 15 min post-curing period (right side image of figure 3b). It has been reported in the literature that when 3D printing is done with thin objects, then there is a likelihood of plastic deformation especially in parts with elongated shapes and small thickness in the horizontal direction. In present case, for polymer 4 based formulation, there is no such deformation, which may be due to the pendant pentadecyl chain present in polymer 4 serves as an in-built “internal plasticizer” effectively reducing plastic deformation and preventing warpage in the 3D-printed thin film.

[0132] ADVANTAGES OF THE INVENTION i. The present invention provides novel photocurable acrylate PEEK (Polyether ether ketone) polymers with a modified chemical structure of formula I. ii. The present invention provides a process for the preparation of photocurable acrylate PEEK (Polyether ether ketone) polymer with a modified chemical structure. iii. The present invention provides novel photocurable PEEK polymers that are better or improved than the PEEKs reported in the literature in terms of 3D printing, ease of use, selectivity towards formation of product, lesser warpage, higher resolution 3d printed products etc. iv. The present invention provides novel photocurable PEEK polymers for applications in the field of aerospace, medicine, automotives, robotics, machinery v. The present invention provides compositions comprising effective amount of polymer or mixture of polymers, photocurable acrylated PEEK polymer of formula I and a photoinitiator. vi. The present invention provides a process for preparation of 3D printable composition comprising effective amount of polymer or mixture of polymers, photocurable acrylated PEEK polymer of formula I and a photoinitiator. vii. The present invention provides modified PEEK polymers for room-temperature DLP 3D printing with minimum equipment demand and minimal waste generation. viii. The present invention provides modified PEEK polymers with minimum weight percentage that is sufficient to enhance the mechanical properties of the 3D-printed parts.

Claims

WE CLAIM:

1. A photocurable acrylate polyether ether ketone polymer having a chemical structure of formula I, the formula I is represented by:Formula-I whereinAr is an aromatic unit,R is a radical polymerizable unit, and x is in the range of 10-50.

2. The photocurable acrylate polyether ether ketone polymer of formula I as claimed in claim1, wherein i. the Ar being the aromatic unit is selected from the group comprising of:, and wherein the spacer is selected from -(CH2)n-O-, -(CH2)n-NH2-, and -(CH2)n-COO-; X is (meth)acrylate or urethane acrylate; and n is 2- 6; and ii. the R being the radical polymerizable unit is selected from the group comprising of:

3. The photocurable acrylate polyether ether ketone polymer of formula I as claimed in claim 1, wherein the photocurable acrylate polyether ether ketone polymer is selected from the group comprising of:Polymer 3;wherein x is in the range of 10-50.

4. A process for the preparation of the photocurable acrylate polyether ether ketone polymer of formula I as claimed in claim 1, the process comprising steps of: a) preparing a mixture comprising at least two aromatic (Ar) precursors, a base, a reaction medium and a 1stsolvent; b) reacting and refluxing the mixture of step a) under stirring at temperature in the range of 120-140 °C for time period in the range of 2-4 h followed by increasing the temperature to 170-190 °C to remove water and the 1stsolvent, and to obtain intermediate PEEK polymer compound of formula IIFormula II; wherein Ar and x is same as defined above; c) reacting the crude intermediate PEEK polymer compound of formula II of b) with a radical polymerizable unit containing precursor solution at temperature in the range of 20-26 °C for time period in the range of 2-4 h to obtain the photocurable acrylate PEEK polymer of formula I; andd) optionally precipitating, washing and drying the photocurable acrylate PEEK polymer of formula I of c) to obtain pure photocurable acrylate PEEK polymer of formula I.

5. The process as claimed in claim 4, wherein the radical polymerizable unit containing precursor solution is prepared by dissolving a radical polymerizable unit containing precursor in a solvent, wherein the solvent is selected from the group comprising of toluene, dimethyl acetamide, and so on; and the radical polymerizable unit containing precursor is selected from the group comprising of 2-hydroxyethyl 4-fluoro benzoate, acryloyl chloride, and PEEK polymer.

6. A process for the preparation of the photocurable acrylate polyether ether ketone polymer of formula I as claimed in claim 1, the process comprising steps of: a) preparing a mixture comprising at least two aromatic (Ar) precursors and a base in presence of a reaction medium and a 1stsolvent; b) reacting and refluxing the mixture of step a) under stirring at temperature in the range of 120-140 °C for time period in the range of 2-4 h followed by increasing the temperature to 170-190 °C to remove water and the 1stsolvent, and to obtain intermediate PEEK polymer compound of formula IIFormula II; wherein Ar and x is same as defined above; c) preparing a solution of the intermediate PEEK polymer compound of formula II of b) by dissolving in a 2ndsolvent and mixing with a catalyst; d) dropwise adding a radical polymerizable unit containing precursor solution with the crude intermediate PEEK polymer compound of formula II solution containing catalyst of c) for time period in the range of 25-35 minutes to obtain a reaction mixture;e) mixing the reaction mixture of d) under stirring at temperature in the range of 20-26 °C for time period in the range of 1.5-2.5 h followed by stirring at temperature in the range of 25-35 °C for time period in the range of 11-13 h to obtain the photocurable acrylate PEEK polymer of formula I; and f) optionally precipitating, washing and drying the photocurable acrylate PEEK polymer of formula I of e) to obtain pure photocurable acrylate PEEK polymer of formula I.

7. The process as claimed in claim 4 or 6, wherein the at least two aromatic (Ar) precursors are selected from the group comprising of combination of any two of Bisphenol A, 4,4’- difluoro benzophenone, 3-pentadecyl 4,4'-biphenol, phenolphthalein, 4,4'-((3- methoxyphenyl)methylene)bis(2-methoxyphenol) (DMBM), and 4,4-Bis(4- hydroxyphenyl)valeric acid; the base is selected from the group comprising of potassium carbonate, calcium carbonate, sodium carbonate, triethylamine, and potassium bicarbonate; the reaction medium is selected from the group comprising of dimethyl acetamide and toluene; and the 1stsolvent is selected from the group comprising of toluene and dimethyl acetamide.

8. The process as claimed in claim 6, wherein the 2ndsolvent is selected from the group comprising of dimethyl formamide (DMF) and dichloromethane (DCM); the catalyst is selected from the group comprising of dibutyltindilaurate (DBTDL) and Lewis acid catalyst; the radical polymerizable unit containing precursor solution is prepared by dissolving a radical polymerizable unit containing precursor in a solvent, wherein the solvent is selected from the group comprising of DMF and DCM; and the radical polymerizable unit containing precursor is selected from the group comprising of 2-isocyanatoethyl methacrylate and acryloyl chloride.

9. A polymer composition for 3D printing, comprising an effective amount of: i. polymer, ii. the photocurable acrylated PEEK polymer of formula I as claimed in claim 1 is in the range of 5-15wt %, and iii. a photoinitiator is in the range of 0.5- 1.5 wt % .

10. The polymer composition as claimed in claim 9, wherein the polymer is selected from Tricyclo[5.2.1.02,6]decane-dimethanol diacrylate (TCDDA), Bisphenol A ethoxylate dimethacrylate (BPAEDMA), Isobornyl methacrylate, and Tris(2-Hydroxyethyl) Isocyanurate Triacrylate or any combination thereof; the photoinitiator is selected from (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), 2-hydroxy 2-methylpropiophenone, bisacylphosphine oxide (BAPO), and benzoyl peroxide.

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