Patent Publication Number: US-2019177484-A1

Title: Aromatic polyimides suitable for 3d printing processes

Description:
CLAIM OF PRIORITY 
     This application claims priority from U.S. Provisional Patent Application Ser. No. 61/882,832 bearing Attorney Docket Number 12013039 and filed on Sep. 26, 2013, which is incorporated by reference. 
    
    
     GOVERNMENT LICENSE RIGHTS 
     The invention described herein was made in performance of work under NASA Cooperative Agreement No. NNX12AP27A and is subject to the provisions of Section 20135 of the National Aeronautics and Space Act (51 U.S.C. 20135). 
    
    
     FIELD OF THE INVENTION 
     This invention concerns the production of new aromatic polyimides suitable for use in the manufacture of thermoplastic polymer articles via 3D printing, also known as “additive manufacturing” or “fused deposition modeling”. 
     BACKGROUND OF THE INVENTION 
     High performance imide polymers are characterized by excellent thermal stability, solvent resistance and high glass transition temperatures (Tg). U.S. Pat. No. 7,015,304 and RE43,880 (both Chuang), the disclosures of which are incorporated by reference, disclose the preparation by a batch process of solvent-free, low-melt imide oligomers and thermosetting polyimides, and to the process of preparing such oligomers and polyimides. 
     U.S. Pat. No. 6,066,710 (Becker et al.) discloses an extrusion process for making aromatic polyimides from symmetrical dianhydrides. 
     Also U.S. Pat. No. 8,093,348 (Chuang), the disclosure of which is incorporated by reference, discloses a variety of starting asymmetric dianhydride monomers, diamine monomers, and endcap monomers useful for making aromatic polyimide polymers. 
     None of these prior efforts has addressed the particular and peculiar requirements for polymerizing monomers to yield new aromatic polyimides which are suitable for use in 3D printing. 
     3D printing (also known by the other phrases identified above) is being hailed in the polymer industry as a new means of forming shaped polymeric articles, literally from the ground up. Like soldering, a space is filled by a material coming from a filamentary form and being heated for delivery precisely to the x-y-z coordinates of that space. A lattice or scaffold of supporting material is also often delivered to adjoining spaces in the same precise manner to fortify the polymeric material of the shaped, printed article until that polymeric material sufficiently cools to provide a final rigid structure in the desired shape, which can be separated from the supporting material. 
     The polymeric material considered for use in 3D printing has included customary semi-crystalline polymers but has recently also focused on polymer resins and blends of polymer resins which have high temperature performance properties. Aromatic polyimide has been considered a candidate for use in 3D printing. 
     SUMMARY OF THE INVENTION 
     What the art needs is an aromatic polyimide having a Tg greater than about 220° C. which is sufficiently ductile that it can be formed into a filament having a diameter ranging from about 1.6 to about 2.1 mm and preferably from about 1.74 to about 1.86 mm and sufficiently flexible that such filament can be wound about a core having a diameter of from about 15 cm to about 25 cm and preferably from about 19 cm to about 22 cm. 
     Stated another way, the aromatic polyimide needs to be sufficiently ductile and flexible that filament of the diameters identified above can form a loop of about 64 cm (25.13 inches) in circumference. 
     Stated another way, the aromatic polyimide having a high Tg needs to be sufficiently ductile and flexible that filament of the diameters identified above in a length of about 38 cm (15 inches) can be bent upon itself, such that the opposing ends of that length of filament can touch each other. 
     Thus, by any of these three means of expression, aromatic polyimides having high Tg values in excess of 220° C. and preferably in excess of 250° C. can be included in the cadre of resins available for the emerging industry of 3D printing of articles using polymers. 
     The present invention has made 3D printing for high Tg resins possible by synthesizing new aromatic polyimides which are both tough enough to be made into a 3D printing filament of the diameter described above and also flexible enough to be wound about a spool for delivery of the filament to the location of a 3D printing head. 
     None of the prior art identified above arose in the time when the particularities of 3D printing were truly understood, particularly for high temperature polymers which have melting temperatures hotter than a pizza oven. 
     The present invention utilizes a particular combination of monomers: (a) an asymmetric dianhydride; in reaction with (b) one or more aromatic diamines; while being subjected to a competing reaction with (c) a mono-anhydride capable of capping the end(s) of the growing polyimide polymer chains. 
     Unfortunately, preparation of high performance imide polymers involve difficult reactions and can benefit from reactive extrusion, a continuous process with timed introduction of the ingredients to form the imide oligomer taught in U.S. Pat. No. 7,015,304 and RE43,880 (both Chuang). 
     But Chuang did not recognize the particular properties necessary for making the high Tg polymer into filaments to be wound upon a spool for 3D printing. Hence, this invention involves synthesis of new polymers. 
     Controlled preparation of high performance imide polymers via reactive extrusion was identified in PCT Patent Publication WO 2013/006621 (Golba et al.), in a manner by which the endcap was to be introduced into the extruder at a zone downstream from the throat and the mixing zone of the extruder. 
     Unexpectedly, as an alternative to Golba et al., it has been found in the present invention that all ingredients, including the endcap, can be added at the throat of the extruder, establishing the competition for the diamine reaction sites between the dianhydride and the endcap from the beginning of the extrusion process. 
     One aspect of the invention is an aromatic polyimide selected from the group consisting of: 
     (a) Poly (2-{4-[3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-5-(2-{3-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl)-2,3-dihydro-1H-isoindole-1,3-dione); 
     (b) Poly (5-{2-[3-(4-{5-[2-(4-{3-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenoxy}phenyl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]-1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl}phenoxy)phenyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl}-2-{4-[3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-2,3-dihydro-1H-isoindole-1,3-dione); 
     (c) Poly (2-{4-[3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-5-[2-(3-{4-[5-(2-{4-[4-(2-{4-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}propan-2-yl)phenoxy]phenyl}-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl]phenoxy}phenyl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]-2,3-dihydro-1H-isoindole-1,3-dione); 
     (d) Poly (2-{4-[3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-5-[2-(3-{4-[5-(2-{4-[2-(3-{2-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenyl]propan-2-yl}phenyl)propan-2-yl]phenyl}-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl]phenoxy}phenyl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]-2,3-dihydro-1H-isoindole-1,3-dione); and 
     (e) combinations thereof. 
     Another aspect of the present invention is an aromatic polyimide selected from the group consisting of: 
     (a) the reaction product of (1) 3, 4′-oxydianiline (3,4′ ODA); (2) 2,3,3′,4′-biphenyldianhydride (a-BPDA); and (3) phthalic anhydride in a molar ratio of 1.0:0.975-0.985:0.03-0.05; 
     (b) the reaction product of (1) 3, 4′-oxydianiline (3,4′ ODA); (2) 1,3-Bis(4-aminophenoxy)benzene (1,3,4′-APB); (3) 2,3,3′,4′-biphenyldianhydride (a-BPDA); and (4) phthalic anhydride in a molar ratio of 0.9:0.1:0.975-0.98:0.04-0.05; 
     (c) the reaction product of (1) 3, 4′-oxydianiline (3,4′ ODA); (2) 2,2-Bis(4-[4-aminophenoxy]phenyl)propane (BAPP); (3) 2,3,3′,4′-biphenyldianhydride (a-BPDA); and (4) phthalic anhydride in a molar ratio of 0.9:0.1:0.975:0.05; and 
     (d) the reaction product of (1) 3, 4′-oxydianiline (3,4′ ODA); (2) 4,4′-[1,3-phenylenebis(1-methyl-ethylidene)bisaniline (Bisaniline-M); (3) 2,3,3′,4′-biphenyldianhydride (a-BPDA); and (4) phthalic anhydride in a molar ratio of 0.9:0.1:0.975:0.05; and combinations thereof. 
     Another aspect of the present invention is an aromatic polyimide comprising (a) 3, 4′-oxydianiline (3,4′ ODA) monomer; (b) 2,3,3′,4′-biphenyldianhydride (a-BPDA) monomer; and (c) phthalic anhydride monomer at a molar ratio sufficient to produce the aromatic polyimide having a glass transition temperature of more than 220° C. and ductility to be wound in the form of a filament of about 2 mm diameter around a spool having a diameter of 8 inches (20.32 cm). 
     Embodiments of the invention are explained with reference to the drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a schematic view of the reactive extrusion process of the invention. 
     
    
    
     EMBODIMENTS OF THE INVENTION 
     Ingredients for Preparing the High Temperature Polyimides 
     Table 1 shows the ingredients used to prepare the novel polyimides. The amount of endcap determines the molecular weight of the resulting aromatic polyimide because the endcap competes with the asymmetric dianhydride for reaction sites at the diamine(s). It has been found that to synthesize filament-quality polyimide, the amount of phthalic anhydride endcap should be less than about 2 mole percent of reactant. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Brand Name 
                 Ingredient 
                 Formula 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
            
               
                 Diamines 
               
               
                   
               
            
           
           
               
               
               
            
               
                 3,4′ ODA 
                 3,4′-oxydianiline, Mw = 200.24, Tm = 74 ~ 75° C., CAS No. 2657-87-6 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 1,3,4′-APB 
                 1,3-Bis(4-aminophenoxy)benzene, Mw = 292.3, Tm = 116° C., CAS No. 2479-46-1 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 BAPP 
                 2,2-Bis(4-[4-aminophenoxy]phenyl)propane, Mw = 410.5, Tm = 128° C., CAS No. 13080- 86-9 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
               
                 Bisaniline-M 
                 4,4′-[1,3-phenylenebis(1-methyl- ethylidene)bisaniline, Mw = 344.5, Tm = 110-114° C., CAS No. 2687-27-6 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
            
               
                 Asymmetric Dianhydride 
               
               
                   
               
            
           
           
               
               
               
            
               
                 a-BPDA 
                 2,3,3′,4′-Biphenyltetracarboxylic dianhydride, CAS No. 36978-41-3 Mw = 294.21, Tm = 196 to 197° C. 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
           
               
            
               
                 Endcap 
               
               
                   
               
            
           
           
               
               
               
            
               
                 PA 
                 Phthalic anhydride, MW = 148.12 (Tm = 131 ~ 134° C., and Tb = 284° C.) (CAS: 85-44-9) 
                 
                   
                     
                     
                         
                         
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     This invention allows for the option of using multiple diamines in the polymerization of the polyimide, so long as one of the diamines is 3,4′ ODA. As seen in the chart above, the second diamine used can be any of 1,3,4′-APB, BAPP, or Bisaniline-M. 
     But not 1,3,-Bis(3-aminophenoxy)benzene, also known as 1, 3, 3′-APB. 
     In a totally unpredictable manner, with confirmation of the experimental results, it was found that (and reported in the Examples below) that use of 1,3,-Bis(3-aminophenoxy)benzene (1,3,3′ APB) as a second diamine was a failure at synthesizing an acceptable polyimide via reactive extrusion. The result of the attempt was a material that was too viscous to be able to flow in the extruder, even when the processing temperatures in the zones were increased to the maximum of the extruder, 400° C. It was observed when the extruder was opened for cleaning that the material had become adhered to the barrel of the extruder. 
     It is not known why 1, 3, 3′-APB fails while 1, 3, 4′-APB succeeds. A comparison of the two formulae shows how subtle and unpredictable the difference is between success and failure: 
     1, 3, 3′-APB: 
     
       
         
         
             
             
         
       
     
     1, 3, 4′-APB: 
     
       
         
         
             
             
         
       
     
     The orientation of the phenyl linkages between the benzene rings, relative to the orientation of the amine groups on the end benzene rings is the only difference. The meta position fails; the para position succeeds. 
     For this reason, it is not presently possible for one having ordinary skill in the art to predict which combination of asymmetric dianhydride, diamine(s), and endcap will result in a new polyimide resin with sufficient ductile and flexible strength to be formed into a filament and wound upon a spool of conventional size for use in 3D printing. 
     Concurrent or Sequential Reactive Extrusion 
     One method of reaction is the contact of the endcap with the diamine concurrent with the contact of the dianhydride with the diamine, in order to establish a competition for diamine reaction sites as soon as melting has commenced in the upstream zones of an extruder. The melt-mixing of the dianhydride and the diamine can result in suitable reaction, even while the endcap is also competing for reaction with the diamine(s) in the extruder. 
       FIG. 1  provides a schematic view of the reactive extrusion method useful for the polyimide. 
     Alternatively, as explained in Golba et al., a second method of reaction can be the delayed addition of endcap in a later zone, such as the fourth zone, allowing the dianhydride and the diamine(s) to melt and commence reaction before introduction of the endcap commences competition for the diamine reaction sites. 
     The process can be based on the use of an extruder  100  having a source of power  120  and a series of heated zones  130  through which ingredients travel in a molten state. The extruder can be a twin screw extruder, either co-rotating or counter-rotating and have a screw diameter ranging from 16 mm to 45 mm. 
     The series of heated zones  130  can number more than six and usually eight or nine, allowing the establishment of different temperatures associated with different segments of screws (not shown) propelling the molten ingredients through the extruder and encountering other ingredients in conditions ripe for planned reaction.  FIG. 1  shows twelve zones  130  for extruder  100 . 
     Among the series of zones is a first unheated or cooled zone or throat  140  of the extruder, into which all of the ingredients are added. In the alternative approach, sequential reactive extrusion, a subsequent or downstream zone  150  contains a port for injection of at least one other ingredient. After the last ingredient(s) is(are) added at zone  150 , regardless of concurrent or sequential technique, further melt-mixing and planned reaction occur, until an evacuation zone  160  is reached further downstream. Zone  160  can be connected to a source of vacuum power  170  to vent any volatiles, such as water or steam. The melted, mixed, and reacted product of the extruder  100  is extruded through a die  180 , for further processing such as pelletizing for later melt-mixing or reaction. 
     Alternatively, directly for 3D printing, the die  180  can be of a diameter to yield filaments of a diameter of from about 1.6 to about 2.1 mm and preferably from about 1.7 mm to about 1.9 mm, and the extrudate can be wound directly upon the spool for later use in the 3D printing in any shape conceivable in three dimensional space. 
     In the present invention, the reactive extruder  100  can be configured to have a first feeder  200 , a second feeder  220 , and a third feeder  230  to introduce the dianhydride, the diamine, and the endcap, respectively, into the throat  140 , commencing the journey through the extruder in which the early or upstream zones are heated to melt all three or more ingredients and to facilitate a reaction among them. 
     At the throat, shown as  140  in  FIG. 1 , the endcap can be introduced via third feeder  230  even before the dianhydride and the diamine to have begun reacting. The endcap can be a solid or a liquid, preferably, the latter to assist in the competition of reacting with the diamine while the dianhydride also is reacting with the diamine. In the alternative, sequential technique, the feeder  230  delivers the endcap at a downstream zone  150 . 
     The reaction temperature, as reported by Chuang for a batch process, can range from about 232° to about 280° C. 
     However, in this invention, it has been found that each of the zones of the reactive extruder should be heated to a temperature within the range of 320° C. to 400° C. Conventionally, the temperature remains the same or increases for the sequential zones, until the die zone  180 , at which the same or slightly lower temperature prepares the extrudate for exit from the extruder and cooling into strands, pellets, etc. 
     Those persons having ordinary skill in the art of reactive extrusion, without undue experimentation, can select the appropriate temperatures for the zones within the 320° C. to 400° C. range identified above, as a result of review of the Examples below. Also, those same persons, without undue experimentation, can establish screw rotation revolutions per minute to establish the time of transit through each zone of the extruder  100 , which can be a factor in the kinetics of the reactive extrusion planned for the dianhydride and diamine in the concurrent or sequential presence of the monoanhydride endcap which is reactive with the diamine(s) but non-reactive thereafter. 
     Usefulness of the Invention 
     The specific polyimides synthesized according to this invention are engineered for use in the 3D printing technique of plastic article shaping. Simple or complex shapes can be printed digitally relying upon the x-y-z coordinates of space and computer software to drive the printer using filaments of the polyimides of this invention to melt, deposit, and cool layer-by-layer in the z axis above the x-y plane to build any conceivable three-dimensional polyimide object. 
     Combining the emerging technique of 3D printing with the high temperature performance of polyimide is a tremendous combination of manufacturing processing and end-use performance not previously achieved. 3D printed polymer articles can be of any form or shape conceivable, even a Möbius strip. 
     Composites of the polyimides of this invention with other ingredients added for functional purposes can be used in a number of high performance articles, such as lightweight polymer composites (e.g., airframe and engine components); military and commercial aircraft; missiles, radomes, and rockets, etc.; high temperature laminates; electrical transformers; bushings/bearings for engines; oil drilling equipment; oil drilling risers; automotive chassis bearings; and films for use in electronics, fuel cells and batteries. 
     The new production of composites begins with the solvent-less reactive extrusion process described above, which has resulted in polyimide in the form of dry powders, pellets, filaments, films, etc. The production utilizes powder or pellets of the polyimide to be fed as solid articles into a single screw extruder with an appropriate film or sheet extrusion die and operating at temperatures above the melting point of the polyimide. The extruder would rapidly melt the dry polymer to produce a thin film emerging from the die. 
     It is also possible to include carbon, glass, or synthetic fibers as additives in the reactive extrusion to form the aromatic polyimide. 
     It is also possible for the polyimide being reactively extruded to be extruded using a sheet or film die in the melt form directly onto fibers (woven or nonwoven) for cooling and subsequent use. 
     Examples further explain the invention. 
     EXAMPLES 
     Table 2 shows the acceptable, desirable, and preferable molar ratio ranges of the monomers useful for synthesizing the polyimides. The polyimide can comprise, consist essentially of, or consist of these monomers. The monomers can be introduced separately into the throat of the extruder as seen in  FIG. 1  or pre-blended before addition via a single feeder. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Molar Ratios 
                 Acceptable 
                 Desirable 
                 Preferable 
               
               
                   
               
             
            
               
                 Diamine(s) 
                 1.0 
                 1.0 
                 1.0  
               
               
                 Asymmetric Dianhydride 
                 0.88-0.98 
                 0.97-0.98 
                 0.97-0.98 
               
               
                 Endcap 
                 0.03-0.24 
                 0.04-0.05 
                 0.05 
               
               
                   
               
            
           
         
       
     
     Table 3 shows the ingredients used for the Examples and the Comparative Example. Tables 4-6 show the molar ratios of the ingredients, the extrusion reaction conditions, and the results. 
     
       
         
           
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                 Commercial 
               
               
                 Brand Name 
                 Ingredient and Purpose 
                 Source 
               
               
                   
               
             
            
               
                 3,4′ ODA 
                 3,4′-oxydianiline, Mw = 
                 Miki Sanyo (USA) 
               
               
                   
                 200.24, Tm = 74~75° C. 
                 Inc. 
               
               
                 1,3,4′-APB 
                 1,3-Bis(4- 
                 Miki Sanyo (USA) 
               
               
                   
                 aminophenoxy)benzene, Mw = 
                 Inc. 
               
               
                   
                 292.3, Tm = 116° C. 
               
               
                 1,3,3′-APB 
                 1,3,-Bis(3- 
                 Miki Sanyo (USA) 
               
               
                   
                 aminophenoxy)benzene, Mw = 
                 Inc. 
               
               
                   
                 292.3, Tm = 106.5-110° C. 
               
               
                 BAPP 
                 2,2-Bis(4-[4- 
                 Mitsui Chemical 
               
               
                   
                 aminophenoxy]phenyl)propane, 
               
               
                   
                 Mw = 410.5, Tm = 128° C. 
               
               
                 Bisaniline-M 
                 4,4′-[1,3-phenylenebis(1- 
                 Mitsui Chemical 
               
               
                   
                 methyl-ethylidene)bisaniline, 
               
               
                   
                 Mw = 344.5, Tm = 110-114° C. 
               
               
                 a-BPDA 
                 2,3,3′,4′- 
                 Miki Sanyo (USA) 
               
               
                   
                 Biphenyltetracarboxylic 
                 Inc. 
               
               
                   
                 dianhydride, CAS No. 36978- 
               
               
                   
                 41-3 Mw = 294.21, Tm = 196 
               
               
                   
                 to 197° C. 
               
               
                 PA 
                 Phthalic anhydride, 
                 Sigma Aldrich 
               
               
                   
                 MW = 148.12 
               
               
                   
                 (Tm = 131~134° C., 
               
               
                   
                 and Tb = 284° C.) 
               
               
                   
                 (CAS: 85-44-9) 
               
               
                 STABILIZER 
                 IRGAFOS P-EPQ FF 
                 BASF 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
             
               
                   
                 TABLE 4 
               
             
            
               
                   
                   
               
               
                   
                 Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 A 
                 B 
                 C 
                 D 
                 E 
                 F 
                 G 
               
            
           
           
               
               
            
               
                   
                 Mole ratio of Diamine(s):a-BPDA:PA 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 1:0.95:0.1 
                 1:0.88:0.24 
                 1:0.88:0.24 
                 1:0.88:0.24 
                 1:0.9:0.2 
                 1::0.92:0.16 
                 1:0.9:0.2 
               
               
                   
                   
               
            
           
           
               
            
               
                 Monomers (Mole %) 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 3,4′-ODA 
                 48.78 
                 47.17 
                 47.17 
                 47.17 
                 47.62 
                 48.08 
                 47.62 
               
               
                 1,3,4′-APB 
               
               
                 1,3,3′-APB 
               
               
                 BAPP 
               
               
                 Bisaniline-M 
               
               
                 a-BPDA 
                 46.34 
                 41.51 
                 41.51 
                 41.51 
                 42.86 
                 44.23 
                 42.86 
               
               
                 PA 
                 4.88 
                 11.32 
                 11.32 
                 11.32 
                 9.52 
                 7.69 
                 9.52 
               
               
                 Stabilizer, Irgafos P- 
                 0 
                 0.1 
                 0.1 
                 0 
                 0 
                 0 
                 0 
               
               
                 PEPQ FF, wt % in total 
               
               
                 formulation 
               
            
           
           
               
               
            
               
                 Extruder 
                 Prism 16 millimeter Twin Screw Extruder 
               
               
                 Order of addition 
                 All ingredients added at throat 
               
            
           
           
               
            
               
                 Temperature at different zones, ° C. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Zone 1 
                 n/a 
                 280 
                 280 
                 280 
                 280 
                 280 
                 300 
               
               
                 Zone 2 
                 100 
                 280 
                 280 
                 280 
                 280 
                 280 
                 300 
               
               
                 Zone 3 
                 220 
                 320 
                 320 
                 320 
                 320 
                 320 
                 350 
               
               
                 Zone 4 
                 220 
                 320 
                 320 
                 320 
                 320 
                 320 
                 350 
               
               
                 Zone 5 
                 220 
                 350 
                 350 
                 350 
                 350 
                 350 
                 350 
               
               
                 Zone 6 
                 230 
                 350 
                 350 
                 350 
                 350 
                 350 
                 370 
               
               
                 Zone 7 
                 230 
                 350 
                 350 
                 350 
                 350 
                 350 
                 370 
               
               
                 Zone 8 (vacuum port) 
                 230 
                 350 
                 350 
                 350 
                 350 
                 350 
                 370 
               
               
                 Zone 9 
                 230 
                 350 
                 350 
                 350 
                 350 
                 350 
                 380 
               
               
                 Die 
                 230 
                 None 
                 370 
                 370 
                 340 
                 340 
                 380 
               
               
                 Screw rpm 
                 250 
                 300 
                 300 
                 300 
                 300 
                 300 
                 250~300 
               
               
                 Observation at Die 
                 Failure 
                 Molten 
                 Molten 
                 Molten 
                 Molten 
                 Molten 
                 Molten 
               
               
                   
                   
                 strand but 
                 strand but 
                 strand but 
                 strand but 
                 strand but 
                 strand but 
               
               
                   
                   
                 brittle when 
                 brittle when 
                 brittle when 
                 brittle when 
                 brittle when 
                 brittle when 
               
               
                   
                   
                 cooled. 
                 cooled. 
                 cooled. 
                 cooled. 
                 cooled. 
                 cooled. 
               
               
                 Tg measured by DSC, ° C. 
                 Not tested 
                 Not tested 
                 Not tested 
                 245 
                 243 
                 236.2 
                 240.95 
               
               
                 Mn by GPC 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 5601 
               
               
                 Mw by GPC 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 8779 
               
               
                 Mw/Mn 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 1.567 
               
               
                 Filament possibility 
                 No 
                 No 
                 No 
                 No 
                 No 
                 No 
                 No 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
             
               
                   
                 TABLE 5 
               
             
            
               
                   
                   
               
               
                   
                 Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 H 
                 1 
                 2 
                 3 
                 I 
                 4 
                 5 
               
            
           
           
               
               
            
               
                   
                 Mole ratio of Diamine(s):a-BPDA:PA 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 1:0.95:0.1 
                 1:0.975:0.05 
                 1:0.985:0.03 
                 0.9:0.1:0.975:0.05 
                 0.9:0.1:0.975:0.05 
                 0.9:0.1:0.975:0.05 
                 0.9:0.1:0.975:0.05 
               
               
                   
                   
               
            
           
           
               
            
               
                 Monomers (Mole %) 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 3,4′-ODA 
                 48.78 
                 49.38 
                 49.63 
                 44.44 
                 44.44 
                 44.44 
                 44.44 
               
               
                 1,3,4′-APB 
                   
                   
                   
                   
                   
                 4.94 
               
               
                 1,3,3′-APB 
                   
                   
                   
                   
                 4.94 
               
               
                 BAPP 
                   
                   
                   
                 4.94 
               
               
                 Bisaniline-M 
                   
                   
                   
                   
                   
                   
                 4.94 
               
               
                 a-BPDA 
                 46.34 
                 48.15 
                 48.88 
                 48.15 
                 48.15 
                 48.15 
                 48.15 
               
               
                 PA 
                 4.88 
                 2.47 
                 1.49 
                 2.47 
                 2.47 
                 2.47 
                 2.47 
               
            
           
           
               
               
            
               
                 Extruder 
                 Prism 16 millimeter Twin Screw Extruder 
               
               
                 Order of 
                 All ingredients added at throat 
               
               
                 addition 
               
            
           
           
               
            
               
                 Temperature at different zones, ° C. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Zone 1 
                 320 
                 350 
                 360 
                 300 
                 300 
                 350 
                 350 
               
               
                 Zone 2 
                 350 
                 370 
                 360 
                 300 
                 300 
                 350 
                 350 
               
               
                 Zone 3 
                 350 
                 370 
                 370 
                 320 
                 320 
                 350 
                 350 
               
               
                 Zone 4 
                 350 
                 370 
                 370 
                 320 
                 320 
                 350 
                 350 
               
               
                 Zone 5 
                 370 
                 370 
                 370 
                 320 
                 320 
                 350 
                 350 
               
               
                 Zone 6 
                 370 
                 370 
                 380 
                 350 
                 350 
                 350 
                 350 
               
               
                 Zone 7 
                 370 
                 370 
                 380 
                 350 
                 350 
                 350 
                 350 
               
               
                 Zone 8 
                 380 
                 380 
                 380 
                 350 
                 350 
                 350 
                 330 
               
               
                 (vacuum port) 
               
               
                 Zone 9 
                 380 
                 380 
                 380 
                 350 
                 350 
                 350 
                 330 
               
               
                 Die 
                 250 
                 250 
                 150~250 
                 350 
                 350 
                 350 
                 330 
               
               
                 Screw rpm 
                 320 
                 350 
                 360 
                 250 
                 250 
                 250 
                 250 
               
               
                 Observation 
                 Molten 
                 Molten 
                 Molten 
                 Molten 
                 Failure to 
                 Molten 
                 Molten 
               
               
                 at Die 
                 strand but 
                 strand and 
                 strand and 
                 strand and 
                 extrude due 
                 strand and 
                 strand and 
               
               
                   
                 brittle when 
                 ductile when 
                 ductile when 
                 ductile when 
                 to 100% 
                 ductile when 
                 ductile when 
               
               
                   
                 cooled. 
                 cooled. 
                 cooled. 
                 cooled. 
                 torque 
                 cooled. 
                 cooled. 
               
               
                 Tg measured 
                 259.1 
                 275.3 
                 272 
                 270.2 
                 261.6 
                 265.2 
                 270.9 
               
               
                 by DSC, ° C. 
               
               
                 Mn by GPC 
                 9354 
                 28090 
                 not tested 
               
               
                 Mw by GPC 
                 14982 
                 38705 
                 not tested 
               
               
                 Mw/Mn 
                 1.602 
                 1.378 
                 not tested 
               
               
                 Filament 
                 No 
                 Yes, 
                 Yes, 
                 Yes, 
                 No 
                 Yes, 
                 Yes, 
               
               
                 possibility 
                   
                 Filament 
                 Filament 
                 Filament 
                   
                 Filament 
                 Filament 
               
               
                   
                   
                 Made 
                 Made 
                 Made 
                   
                 Made 
                 Made 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
             
               
                   
                 TABLE 6 
               
             
            
               
                   
                   
               
               
                   
                 Example 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 J 
                 K 
                 L 
                 M 
                 6 
                 7 
                 8 
               
            
           
           
               
               
            
               
                   
                 Mole ratio of Diamine(s):a-BPDA:PA 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 0.5:0.5:0.975:0.05 
                 0.75:0.25:0.975:0.05 
                 0.75:0.25:0.985:0.03 
                 0.85:0.15:0.985:0.03 
                 0.9:0.1:0.975:0.05 
                 0.9:0.1:0.975:0.05 
                 0.9:0.1:0.98:0.04 
               
               
                   
                   
               
            
           
           
               
            
               
                 Monomers (Mole %) 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 3,4′-ODA 
                 24.69 
                 37.04 
                 37.22 
                 42.18 
                 44.44 
                 44.44 
                 44.56 
               
               
                 1,3,4′-APB 
                 24.69 
                 12.35 
                 12.41 
                 7.45 
                 4.94 
                 4.94 
                 4.95 
               
               
                 1,3,3′-APB 
               
               
                 BAPP 
               
               
                 Bisaniline-M 
               
               
                 a-BPDA 
                 48.15 
                 48.15 
                 48.88 
                 48.88 
                 48.15 
                 48.15 
                 48.51 
               
               
                 PA 
                  2.47 
                  2.47 
                 1.49 
                 1.49 
                 2.47 
                 2.47 
                 1.98 
               
            
           
           
               
               
            
               
                 Extruder 
                 Prism 16 millimeter Twin Screw Extruder 
               
               
                 Order 
                 All ingredients added at throat 
               
            
           
           
               
            
               
                 Temperature at different zones, ° C. 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 Zone 1 
                 300~360 
                 300~380 
                 350 
                 350~400 
                 350 
                 350 
                 360 
               
               
                 Zone 2 
                 300~360 
                 300~380 
                 350 
                 350~400 
                 350 
                 350 
                 360 
               
               
                 Zone 3 
                 300~360 
                 320~380 
                 350 
                 350~400 
                 350 
                 370 
                 360 
               
               
                 Zone 4 
                 300~360 
                 320~380 
                 350 
                 350~400 
                 350 
                 370 
                 370 
               
               
                 Zone 5 
                 300~340 
                 320~380 
                 350 
                 350~400 
                 350 
                 370 
                 370 
               
               
                 Zone 6 
                 300~340 
                 320~380 
                 350 
                 350~400 
                 350 
                 370 
                 370 
               
               
                 Zone 7 
                 300~340 
                 340~380 
                 350 
                 350~400 
                 350 
                 370 
                 380 
               
               
                 Zone 8 
                 300~340 
                 340~380 
                 350 
                 350~400 
                 350 
                 370 
                 380 
               
               
                 (vacuum port) 
               
               
                 Zone 9 
                 300~320 
                 340~380 
                 350 
                 350~400 
                 350 
                 380 
                 380 
               
               
                 Die 
                 300~320 
                 340~380 
                 350 
                 350~400 
                 350 
                 380 
                 380 
               
               
                 Screw rpm 
                 150~250 
                 150~250 
                 250 
                 400 
                 250 
                 250 
                 250 
               
               
                 Observation 
                 Failure to 
                 Failure to 
                 Failure to 
                 Failure to 
                 Confirms 
                 Confirms 
                 Molten 
               
               
                 at Die 
                 extrude- 
                 extrude- 
                 extrude- 
                 extrude due 
                 success of 
                 success of 
                 strand and 
               
               
                   
                 100% 
                 100% 
                 100% 
                 to 100% 
                 Example 4 
                 Example 4 
                 ductile when 
               
               
                   
                 torque 
                 torque 
                 torque 
                 torque 
                   
                   
                 cooled. 
               
               
                 Tg measured 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 Not tested 
                 262.8~265.2 
               
               
                 by DSC, ° C. 
               
               
                 Mn by GPC 
               
               
                 Mw by GPC 
               
               
                 Mw/Mn 
               
               
                 Filament 
                 No 
                 No 
                 No 
                 No 
                 Yes, 
                 Yes, 
                 Yes, Filament 
               
               
                 possibility 
                   
                   
                   
                   
                 Filament 
                 Filament 
                 Made and Used 
               
               
                   
                   
                   
                   
                   
                 Made 
                 Made 
                 in 3D Printing 
               
               
                   
               
            
           
         
       
     
     Examples 1-8 differ from Comparative Examples A-M based on the practical result that Examples 1-8 were sufficiently ductile and flexible to be useful as filaments for 3D printing. One test employed was using a length of about 38 cm of strand and gently but firmly bending one end of the strand to touch the other end of the strand without breakage. The more robust test was to wind a strand about a 20.32 cm (8 inches) diameter spool actually used in a commercial 3D printer. Either way, Examples 1-8 were successful among all four new aromatic polyimides based on the molar ratios of monomers, the solvent-less reactive extrusion at the stated temperatures and screw speeds, and the use of a die of a size suitable for commercial filaments useful in 3D printers. 
     Examples 1-8 identify new polyimides which can have a Tg ranging from about 260 to about 275° C. and preferably from about 265 to about 270° C. 
     Comparative Examples A-H utilized too much endcap. Examples 1 and 2 were successful because the mole ratio of phthalic anhydride endcap was between 0.03 and 0.05. 
     Examples 3, 4, and 5 introduced BAPP, 1,3,4′-APB, and Bisaniline-M, respectively as a second diamine, with success. Yet, Comparative Example I using 1,3,3′-APB as a second diamine in the same molar ratio as the other three was a complete failure. To confirm that failure, the experiment was repeated with the same unexplainable unexpected result. 
     Comparative Examples J, K, L, and M and Example 6 demonstrated that the molar ratio of the 3,4′-ODA to the molar ratio 1,3,4′-APB needed to be at least 0.9:0.1 in order to perform the reactive extrusion process within acceptable torque ranges. 
     Examples 7 and 8 explored different molar ratios of a-BPDA and phthalic anhydride after the minimum molar ratio of 3,4′-ODA to 1,3,4′-APB was established in Example 6. Example 8 resulted in not only filaments suitable for 3D printing, but also the filament was used to make 3D printed plastic articles, objects resembling the shape of a USA five cent piece, having a glass transition temperature greater than 220° C. 
     The IUPAC names and formulae, respectively, for four new polyimides I-IV are as follows: 
     New Polyimide I: 
     Poly (2-{4-[3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-5-(2-{3-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl)-2,3-dihydro-1H-isoindole-1,3-dione) 
     New Polyimide II: 
     Poly (5-{2-[3-(4-{5-[2-(4-{3-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenoxy}phenyl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]-1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl}phenoxy)phenyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl}-2-{4-[3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-2,3-dihydro-1H-isoindole-1,3-dione) 
     New Polyimide III: 
     Poly (2-{4-[3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-5-[2-(3-{4-[5-(2-{4-[4-(2-{4-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}propan-2-yl)phenoxy]phenyl}-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl]phenoxy}phenyl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]-2,3-dihydro-1H-isoindole-1,3-dione) 
     New Polyimide IV: 
     Poly (2-{4-[3-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenoxy]phenyl}-5-[2-(3-{4-[5-(2-{4-[2-(3-{2-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenyl]propan-2-yl}phenyl)propan-2-yl]phenyl}-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl]phenoxy}phenyl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]-2,3-dihydro-1H-isoindole-1,3-dione). 
     New Polyimide I: 
     
       
         
         
             
             
         
       
     
     where n is a number from about 30 to about 70 and preferably from about 40 to about 65. 
     New Polyimide II: 
     
       
         
         
             
             
         
       
     
     where x is a number from about 3 to about 7 and preferably from about 4 to about 6 and y is a number from about 27 to about 63 and preferably from about 36 to about 59. 
     New Polyimide III: 
     
       
         
         
             
             
         
       
     
     where x is a number from about 3 to about 7 and preferably from about 4 to about 6 and y is a number from about 27 to about 63 and preferably from about 36 to about 59. 
     New Polyamide IV: 
     
       
         
         
             
             
         
       
     
     where x is a number from about 3 to about 7 and preferably from about 4 to about 6 and y is a number from about 27 to about 63 and preferably from about 36 to about 59. 
     The invention is not limited to above embodiments. The claims follow.