EP3387044A1

EP3387044A1 - Additive manufacturing process for improved interlayer adhesion of polyetherimide blends

Info

Publication number: EP3387044A1
Application number: EP16829446.0A
Authority: EP
Inventors: Sarah E. Grieshaber; Malvika BIHARI; Kelly LEUNG; Lakshmikant Suryakant POWALE
Original assignee: SABIC Global Technologies BV
Current assignee: SHPP Global Technologies BV
Priority date: 2015-12-11
Filing date: 2016-12-09
Publication date: 2018-10-17
Also published as: WO2017100520A1; CN108431089A; KR20180088686A; KR102168114B1

Abstract

The present disclosure provides methods of fabricating articles via additive manufacturing, the methods including depositing at least first and second amounts of a molten thermoplastic composition such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article. The thermoplastic composition may include at least first and second populations of polyetherimide, the first and second populations differing in weight-average molecular weight by, e.g., up to about 100 kDa, as determined by gel permeation chromatography (GPC) relative to polystyrene standards.

Description

ADDITIVE MANUFACTURING PROCESS FOR

IMPROVED INTERLAYER ADHESION OF POLYETHERIMIDE BLENDS

TECHNICAL FIELD

[0001] The present disclosure relates to the field of additive manufacturing and to the field of polymer blends.

BACKGROUND

[0002] Articles formed via layer-by -layer additive manufacture can exhibit excellent resolution, durability, and strength. These articles of manufacture can have a wide variety of uses, including as prototypes and as end products as well as molds for end products. In parts produced by additive manufacturing processes such as fused deposition modeling (FDM), however, weak interlayer adhesion due to limited bonding between subsequent layers of the build can decrease the strength of the printed parts in the build direction (also known as the z- direction) and in other directions as well.

[0003] Given the increasing use of additive manufacturing processes, there is a need in the art for an additive manufacturing process capable of producing parts with improved interlayer adhesion to achieve better aesthetic qualities and structural properties. There is also a related need for compositions that enable such improved additive manufacturing processes.

SUMMARY

[0004] In meeting these long-felt needs, the present disclosure provides methods of forming an article, comprising: depositing at least first and second amounts of a molten thermoplastic composition such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, wherein the

thermoplastic composition comprises at least first and second populations of polyetherimide, the first and second populations differing in weight-average molecular weight by up to about 100 kDa, as determined by gel permeation chromatography (GPC) relative to polystyrene standards.

[0005] The present disclosure also provides articles, comprising: at least first and second amounts of thermoplastic composition fused together at a fused region, wherein the thermoplastic composition comprises at least first and second populations of polyetherimide, the at least two or more populations differing in weight-average molecular weight by up to about 100 kDa, as determined by GPC relative to polystyrene standards.

[0006] Additionally provided are methods of forming an article, comprising: depositing a plurality of portions of a molten thermoplastic composition that comprises at least first and second populations of polyetherimide that differ by weight-average molecular weight as determined by GPC relative to polystyrene standards, the depositing being performed such that at least some of the plurality of portions of the thermoplastic composition are fused together so as to form the article.

[0007] The disclosure also provides methods of forming an article, comprising:

depositing at least first and second amounts of a molten thermoplastic composition that comprises polyetherimide such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, the thermoplastic composition comprising a plurality of polyetherimide polymer chains, with up to the lower 50% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa.

[0008] Further provided are methods of forming an article, comprising: depositing at least first and second amounts of a molten thermoplastic composition that comprises

polyetherimide such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, the thermoplastic composition comprising a plurality of polyetherimide polymer chains, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the upper 99.9% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa.

[0009] Additionally provided are articles, comprising: at least first and second amounts of a thermoplastic composition fused together at a fused region, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains (a) with up to the lower 50% by chain weight, of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa (b) with up to the upper 80% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa; or (a) and (b).

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0010] The present disclosure can be understood more readily by reference to the following detailed description taken in connection with the accompanying figures and examples, which form a part of this disclosure. It is to be understood that this disclosure is not limited to the specific devices, methods, applications, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed subject matter. Also, as used in the specification including the appended claims, the singular forms "a," "an," and "the" include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise.

[0011] The term "plurality", as used herein, means more than one. When a range of values is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable. Weight percentages should be understood as not exceeding a combined weight percent value of 100 wt. %. Where a standard is mentioned and no date is associated with that standard, it should be understood that the standard is the most recent standard in effect on the date of the present filing.

[0012] It is to be appreciated that certain features of the disclosed subject matter which are, for clarity, described herein in the context of separate embodiments, can also be provided in combination in a single embodiment. Conversely, various features of the disclosed subject matter that are, for brevity, described in the context of a single embodiment, can also be provided separately or in any subcombination. Further, reference to values stated in ranges includes each and every value within that range. Any documents cited herein are incorporated herein by reference in their entireties for any and all purposes.

[0013] A variety of thermoplastics are used in additive manufacturing techniques. Polyetherimide (PEI) blends are especially suitable, as they offer high heat, strength, and chemical resistance for many injection molding and additive manufacturing (3D printing) applications. In processes such as fused deposition modeling (FDM), however, poor adhesion between layers of deposited material can decrease the strength of the printed part in all directions, especially in the direction of printing. The described control over the melt flow and/or molecular weight of PEI blends leads to improved interlay er adhesion (also known as z-strength) and enhances printed part performance including mechanical, thermal, and flame properties.

[0014] In some embodiments of the methods, a plurality of layers is formed in a preset partem by an additive manufacturing process. "Plurality" as used in the context of additive manufacturing includes 2 or more layers. The maximum number of layers can vary, and may be determined, for example, by considerations such as the size of the article being manufactured, the technique used, the capabilities of the equipment used, and the level of detail desired in the final article. For example, 5 to 100,000 layers can be formed, or 50 to 50,000 layers can be formed.

[0015] The fused layers of printed articles can be of any thickness suitable for FDM processing. The plurality of layers may each be, on average, preferably at least 50 micrometers (microns) thick, more preferably at least 80 microns thick, and even more preferably at least 100 micrometers (microns) thick. In a preferred embodiment, the plurality of sintered layers are each, on average, preferably less than 500 micrometers (microns) thick, more preferably less than 300 micrometers (microns) thick, and even more preferably less than 200 micrometers (microns) thick.

[0016] Accordingly, layers may be, e.g., 50-500, 80-300, or 100-200 micrometers (microns) thick. Articles produced via a filament-based deposition process may, of course, have layer thicknesses that are the same or different from those described above.

[0017] In existing additive manufacturing processes, adhesion may be weakest in the build direction (z-direction) due to incomplete bonding between subsequent layers of the build. Secondary operations such as coating, curing (radiation or thermal), painting, sanding, or heating can improve the structural properties and/or aesthetics of the printed parts. But these operations can, in some cases, add time and cost to a fabrication process.

[0018] Appropriate melt flow control or a decrease in glass transition temperature can help to relieve internal stresses and allow the extruded material to remain in the molten state for a longer period of time, thus increasing bonding with the previously deposited material and strengthening adhesion between the layers in all directions.

[0019] Melt flow adjustment can be achieved by changes in polymer molecular weight, flow promoting additives, or a combination of these methods. The mechanical properties of the polymer also contribute to the strength of the printed part, and must be considered when developing materials with improved z-strength.

[0020] The polyetherimide compositions can include various additives ordinarily incorporated into polymer compositions of this type, with the proviso that the additives are selected so as to not significantly adversely affect the desired properties of the composition. Exemplary additives include catalysts, impact modifiers, antioxidants, thermal stabilizers, light stabilizers, ultraviolet light (UV) absorbing additives, quenchers, plasticizers, lubricants, mold release agents, antistatic agents, visual effect additives such as dyes, pigments, light effect additives, and radiation stabilizers. Combinations of additives can be used, for example, a combination of a heat stabilizer, a mold release agent, and optionally an ultraviolet light stabilizer. In general, the additives are used in the amounts generally known to be effective. The foregoing additives are generally present in an amount from 0.005 to 20 wt %, specifically 0.01 to 10 wt %, based on the total weight of the composition. Alternatively, in some embodiments, our compositions do not contain appreciable amounts of additives, and in some situations, there are no detectable amounts of additives, i.e., additives are substantially absent or absent from the compositions. Accordingly, the foregoing additives can be present in an amount from 0 to less than or equal to an amount selected from 20 wt %, 19 wt % 18 wt %, 17 wt %, 16 wt %, 15 wt %, 14 wt %, 13 wt %, 12 wt %, 11 wt %, 10 wt %, 9 wt %, 8 wt %, 7 wt %, 6 wt %, 5 wt %, 4 wt %, 3 wt %, 2 wt %, 1 wt %, and 0.0001 wt %, based on the total weight of the composition. In another embodiment, no appreciable amount of any additive other than a heat stabilizer, a mold release agent, and optionally an ultraviolet light stabilizer is present in the compositions. In still another embodiment, no detectable amount of any additive other than a heat stabilizer, a mold release agent, and optionally an ultraviolet light stabilizer is present in the compositions.

[0021] Suitable antioxidants can be compounds such as phosphites, phosphonites and hindered phenols or mixtures thereof. Phosphorus-containing stabilizers including triaryl phosphites and aryl phosphonates are useful additives. Difunctional phosphorus containing compounds can also be unseeded. Preferred stabilizers can have a molecular weight greater than or equal to 300. Some exemplary compounds are tris-di-tert-butylphenyl phosphite available from Ciba Chemical Co. as IRGAFOS™ 168 and bis(2,4-dicumylphenyl)pentaerythritol diphosphite available commercially from Dover Chemical Co. as DOVERPHOS™ S-9228.

[0022] Examples of phosphites and phosphonites include: triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert- butylphenyl)phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert- butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite, diisodecyloxy pentaerythritol diphosphite, bis(2,4-di-tert-butyl-6- methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearyl sorbitol tri-phosphite, tetrakis(2,4-di-tert-butyl-phenyl) 4,4'-biphenylene diphosphonite, bis(2,4-di-tert-butyl-6-methylphenyl) methyl phosphite, bis(2,4-di-tert-butyl-6- methylphenyl) ethyl phosphite, 2,2',2"-nitrilo[triethyl tris(3,3',5,5'-tetra-tert-butyl-l, -biphenyl- 2,2'-diyl)phosphite], 2-ethylhexyl(3,3',5,5'-tetra-tert-butyl-l,r-biphenyl-2,2'-diyl)phosphite and 5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-l,3,2-dioxaphosphiran- e. [0023] Combinations comprising more than one organophosphorous compound are contemplated. When used in combination, the organo phosphorous compounds can be of the same type or different types. For example, a combination can comprise two phosphites or a combination can comprise a phosphite and a phosphonite. In some embodiments, phosphorus- containing stabilizers with a molecular weight greater than or equal to 300 are useful.

Phosphorus-containing stabilizers, for example an aryl phosphite, are usually present in the composition in an amount from 0.005 to 3 wt %, specifically 0.01 to 1.0 wt %, based on total weight of the composition.

[0024] Hindered phenols can also be used as antioxidants, for example, alkylated monophenols, and alkylated bisphenols or poly phenols. Exemplary alkylated monophenols include 2,6-di-tert-butyl-4-methylphenol; 2-tert-butyl-4,6-dimethylphenol; 2,6-di-tert-butyl-4- ethylphenol; 2,6-di-tert-butyl-4-n-butylphenol; 2,6-di-tert-butyl-4-isobutylphenol; 2,6- dicyclopentyl-4-methylphenol; 2-(alpha-methylcyclohexyl)-4,6-dimethylphenol; 2,6- dioctadecyl-4-methylphenol; 2,4,6-tricyclohexylphenol; 2,6-di-tert-butyl-4- methoxymethylphenol; nonyl phenols which are linear or branched in the side chains, for example, 2,6-di-nonyl-4-methylphenol; 2,4-dimethyl-6-( -methylundec-l '-yl)phenol; 2,4- dimethyl-6-(l '-methylheptadec-1 '-yl)phenol; 2,4-dimethyl-6-(l '-methyltridec-1 '-yl)phenol and mixtures thereof. Exemplary alkylidene bisphenols include 2,2'-methylenebis(6-tert-butyl-4- methylphenol), 2,2'-methylenebis(6-tert-butyl-4-ethylphenol), 2,2'-methylenebis[4-methyl-6- (alpha-methylcyclohexyl)-phenol], 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'- methylenebis(6-nonyl-4-methylphenol), 2,2'-methylenebis(4,6-di-tert-butylphenol), 2,2'- ethylidenebis(4,6-di-tert-butylphenol), 2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2'- methylenebis[6-(alpha-methylbenzyl)-4-nonylphenol], 2,2'-methylenebis[6-(alpha, alpha- dimethylbenzyl)-4-nonylphenol], 4,4'-methylenebis-(2,6-di-tert-butylphenol), 4,4'- methylenebis(6-tert-butyl-2-methylphenol), l, l -bis(5-tert-butyl-4-hydroxy-2- methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol, 1 ,1 ,3- tris(5-tert-butyl-4-hy droxy-2-methylphenyl)butane, 1 , 1 -bis(5-tert-butyl-4-hy droxy-2-methyl- phenyl)-3-n-dodecylmercaptobutane- , ethylene glycol bis[3,3-bis(3'-tert-butyl-4'- hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene, bis[2- (3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphe- nyl]terephthalate, 1, 1 -bis- (3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane, 2,2- bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane- , 1 , 1 ,5,5 -tetra-(5-tert- butyl-4-hydroxy-2-methylphenyl)pentane and mixtures thereof. [0025] The hindered phenol compound can have a molecular weight of greater than or equal to 300 g/mole. The high molecular weight can help retain the hindered phenol moiety in the polymer melt at high processing temperatures, for example, greater than or equal to

300. degree. C. Hindered phenol stabilizers, are usually present in the composition in an amount from 0.005 to 2 wt %, specifically 0.01 to 1.0 wt %, based on total weight of the composition.

[0026] Examples of mold release agents include both aliphatic and aromatic carboxylic acids and their alkyl esters, for example, stearic acid, behenic acid, pentaerythritol tetrastearate, glycerin tristearate, and ethylene glycol distearate. Poly olefins such as high-density

polyethylene, linear low-density polyethylene, low-density polyethylene, and similar poly olefin homopolymers and copolymers can also be used a mold release agents. Mold release agents are typically present in the composition at 0.05 to 10 wt %, based on total weight of the composition, specifically 0.1 to 5 wt %. Preferred mold release agents will have high molecular weight, typically greater than 300, to prevent loss of the release agent from the molten polymer mixture during melt processing.

[0027] In particular, an optional poly olefin can be added to modify the chemical resistance characteristics and mold release characteristics of the composition. Homopolymers such as polyethylene, polypropylene, polybutene can be used either separately or in combination. Polyethylene can be added as high-density polyethylene (HDPE), low-density polyethylene (LDPE), or a branched polyethylene. Poly olefins can also be used in copolymeric form with compounds containing carbonic acid radicals such as maleic acid or citric acid or their anhydrides, acid compounds containing acrylic acid radicals such as acrylic acid ester, and the like, as well as combinations comprising at least one of the foregoing. When present, the poly olefin, in particular HDPET, is used in an amount from more than 0 to 10 wt %, specifically 0.1 to 8 wt %, more specifically from 0.5 to 5 wt %, all based on the total weight of the composition.

[0028] Colorants such as pigment and/or dye additives can also optionally be present. Useful pigments can include, for example, inorganic pigments such as metal oxides and mixed metal oxides such as zinc oxide, titanium dioxide, iron oxides, or the like; sulfides such as zinc sulfides, or the like; aluminates; sodium sulfo-silicates sulfates, chromates, or the like; carbon blacks; zinc ferrites; ultramarine blue; organic pigments such as azos, di-azos, quinacridones, perylenes, naphthalene tetracarboxylic acids, flavanthrones, isoindolinones,

tetrachloroisoindolinones, anthraquinones, enthrones, dioxazines, phthalocyanines, and azo lakes; Pigment Red 101 , Pigment Red 122, Pigment Red 149, Pigment Red 177, Pigment Red 179, Pigment Red 202, Pigment Violet 29, Pigment Blue 15, Pigment Blue 60, Pigment Green 7, Pigment Yellow 1 19, Pigment Yellow 147, Pigment Yellow 150, and Pigment Brown 24; or combinations comprising at least one of the foregoing pigments. Pigments are generally used in amount from 0 to 10 wt %, specifically 0 to 5 wt %, based on the total weight of the

composition. In some instances, where improved impact is desired, pigments such as titanium dioxide will have a mean particle size of less than 5 microns.

[0029] Illustrative Embodiments

[0030] A qualitative adhesion method was used to predict interlayer adhesion of various PEI resin grades during the 3D printing process. Exemplary PEI pellets were injection molded into flame bars with thickness of 1 mm, and two bars of the same material were clamped together and placed in an oven at a temperature 3-5 degrees higher than the glass transition temperature of the polymer. After cooling, the adhesion was characterized as weak for bars that were pulled apart easily, as medium for bars that were welded but could be pulled apart while remaining intact, and as strong for bars that were completely welded and could not be pulled apart without breaking.

[0031] Table 1 below provides illustrative adhesion results for various exemplary PEI grades (ULTEM™ by SABIC is considered an especially suitable PEI material) after 15 minutes at 220 °C. As flow increased with lower molecular weight for PEI 1 (MW = 57 kDa), PEI 2 (MW = 49 kDa), and PEI 3 (MW = 33 kDa) (all weight average molecular weight, M_w values determined by GPC relative to polystyrene standards), inter-bar adhesion became stronger. Without being bound to any particular theory, these results suggest that materials that include at least some comparatively lower molecular weight (and that are consequently higher flow materials) may have superior interlayer adhesion in 3D printed parts than materials of comparatively higher molecular weight.

[0032] Table 1 provides lap shear adhesion testing data for illustrative PEI bars:

Grade Tg HDT - 1.82 MVR - 337 Mw Adhesion 220 °C,

(°C) MPa (°C) °C, 6.6kgf (kDa) 15 min

Pl -: i I 2 1 7 2d I S 57 oak

PEI 2 217 198 19 49 Medium

Pi : I 3 2 1 5 r. 72 33 Welded [0033] The adhesion results in Table 1 above were confirmed by a lap shear method to measure the strength at break. The failure mode (FIG. 1) is indicative of the strength of the bond between layers.

[0034] Most PEI 1 samples failed by shear at the overlap between the bars (detaching the bars without breaking, failure type 1) or by partial shear and break (type 2). By comparison, PEI 2 and PEI 3 samples failed by breaking at one end of the overlap (type 3), which suggests a stronger inter-layer adhesion.

[0035] Again without being bound to any particular theory, these results confirm that layer-to-layer adhesion was superior for lower molecular weight (higher flow) materials. Also without being bound to any particular theory, the breakage may also be explained by increased brittleness of the lower molecular weight grades, PEI 3 in particular. Further testing (FIG. 2) showed a slight decrease in force at break for PEI 2 as compared to PEI 1, and a more notable decrease for PEI 3 when compared to the higher MW PEI 1.

[0036] Table 2 (below) provides further properties of several illustrative PEI 1 and PEI 3 blen

[0037] The molecular weight is linearly related to the blend ratio of the two grades. Correspondingly, in blending low- and high-molecular weight components, the polydispersity (D) of the blended samples was higher than in the individual components. The glass transition temperature decreased with decreasing molecular weight across the studied range.

[0038] In further evaluations, four experimental blends were injection molded into 3.2mm standard ASTM parts on a 180T molding machine with a flat barrel zone temperature profile at 680F. Parts were tested for flexural, tensile, and impact properties. [0039] Table 3 below provides tensile property data of injection molded, exemplary PEI blen

[0040] Tensile modulus and tensile strength and elongation at yield were essentially the same amongst all samples. There were no noted trends in tensile elongation at break.

[0041] Table 4 below provides flexural property data for several injection-molded PEI blends:

[0042] As shown in the table above, the flexural modulus and flexural stress at yield increased, with an increased in the relative amount of the lower molecular weight PEI.

[0043] Table 5 below provides exemplary impact property data for several injection molded PEI blends:

[0044] As shown above, a reduced impact strength was seen in PEI blend 4 in the MAI test, as the total energy was lower than the other three samples at both temperatures. PEI blend 4 was also the only sample that had 0% ductile failures at 100°C.

[0045] Notched izod impact results at 23 °C did not show a clear trend. Reverse notched izod impact testing at 23°C showed increasing impact strength with increasing proportion of higher molecular weight PEI.

[0046] In summary, increasing the relative proportion of lower-MW PEI in a composition acted to enhance inter-layer adhesion in additive manufacturing. The increased inter-layer adhesion did not come at the expense of a broad range of mechanical properties.

[0047] The following aspects of the present disclosure are illustrative only and do not limit the scope of the disclosure or of the appended claims. [0048] Aspect 1. A method of forming an article, comprising: depositing at least first and second amounts of a molten thermoplastic composition such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, wherein the thermoplastic composition comprises at least first and second populations of polyetherimide (or PEI), the first and second populations differing in weight-average molecular weight by up to about 100 kDa, as determined by gel permeation chromatography (GPC) relative to polystyrene standards.

[0049] Suitable polyetherimides are described in, e.g. , United States published patent application no. 2014/0228462, the entirety of which is incorporated herein by reference.

[0050] Polyetherimides ("PEIs") are amorphous, transparent, high performance polymers having a glass transition temperature ("Tg") of greater than 180 °C. PEIs further have high strength, heat resistance, and modulus, and broad chemical resistance. The high reliability and safety benefits afforded by a polyetherimide from its optical transparency, toughness, and heat resistance can be useful in medical applications.

[0051] Polyetherimides can comprise polyetherimides homopolymers (e.g., polyetherimidesulfones) and polyetherimides copolymers. The polyetherimide can be selected from (i) polyetherimidehomopolymers, e.g., polyetherimides, (ii) polyetherimide co-polymers, and (iii) combinations thereof. Polyetherimides are known polymers and are sold by SABIC Innovative Plastics under the ULTEM™, EXTEM™ , and SILTEM™ resins.

[0052] Polyetherimides can be of formula (1): wherein a is more than 1, for example 10 to 1,000 or more, or more specifically 10 to 500.

[0053] The group V in formula (1) is a tetravalent linker containing an ether group (a "polyetherimide" as used herein) or a combination of an ether groups and arylenesulfone groups (a "polyetherimidesulfone"). Such linkers include but are not limited to: (a) substituted or unsubstituted, saturated, unsaturated or aromatic monocyclic and poly cyclic groups having 5 to 50 carbon atoms, optionally substituted with ether groups, arylenesulfone groups, or a combination of ether groups and arylenesulfone groups; and (b) substituted or unsubstituted, linear or branched, saturated or unsaturated alkyl groups having 1 to 30 carbon atoms and optionally substituted with ether groups or a combination of ether groups, arylenesulfone groups, and arylenesulfone groups; or combinations comprising at least one of the foregoing. Suitable additional substitutions include, but are not limited to, ethers, amides, esters, and combinations comprising at least one of the foregoing.

[0054] The R group in formula (1) includes but is not limited to substituted or unsubstituted divalent organic groups such as: (a) aromatic hydrocarbon groups having 6 to 20 carbon atoms and halogenated derivatives thereof; (b) straight or branched chain alkylene groups having 2 to 20 carbon atoms; (c) cycloalkylene groups having 3 to 20 carbon atoms, or (d) divalent groups of formula (2):

wherein Q l includes but is not limited to a divalent moiety such as -0-, -S-, -C(O)-, -S02-, -SO-, -CyH2y- (y being an integer from 1 to 5), and halogenated derivatives thereof, including perfluoroalkylene groups.

[0055] The linker V may include but are not limited to tetravalent aromatic groups of formula (3):

wherein W is a divalent moiety including -0-, -S02-, or a group of the formula -0-Z-O- wherein the divalent bonds of the -O- or the -0-Z-O- group are in the 3,3', 3,4', 4,3', or the 4,4' positions, and wherein Z includes, but is not limited, to divalent groups of formulas (4):

wherein Q includes, but is not limited to a divalent moiety including -0-, -S-, -C(O),

-SO₂-, -SO-, -C_yH_2y- (y being an integer from 1 to 5), and halogenated derivatives thereof, including perfluoroalkylene groups.

[0056] Polyetherimide may comprise more than 1, specifically 10 to 1,000, or more specifically, 10 to 500 structural units, of formula (5):

wherein T is -O- or a group of the formula -0-Z-O- wherein the divalent bonds of the -O- or the - 0-Z-O- group are in the 3,3', 3,4', 4,3', or the 4,4' positions; Z is a divalent group of formula (3) as defined above; and R is a divalent group of formula (2) as defined above.

[0057] In some embodiments, the thermoplastic composition comprises a bi-, tri-, or other multi-modal distribution of polyetherimides, e.g., a bi-modal distribution of polyetherimide polymers. The modes of the distribution may be equal to one another, e.g., half of the composition comprises PEI of MWi, and the other half of the composition comprises PEI of MW^~ ₂. The width of a distribution (mode) may be such that 1% - 99% of the PEI in that mode is within 10% of the weight average molecular weight for that mode.

[0058] The first and second populations may differ in molecular weight by, e.g. , from about 1 to about 90 kDa, or from about 15 to about 85 kDa, or from about 20 to about 80 kDa, or from about 25 to about 75 kDa, or from about 30 to about 65 kDa, or from about 35 to about 60 kDa, or from about 40 to about 65 kDa, or from about 45 to about 60 kDa, or from about 50 to about 55 kDa. Populations that differ in molecular weight by from about 10 to about 25 kDa (e.g., from about 15 kDa to about 24 kDa) are considered especially suitable.

[0059] Deposition may be accomplished by, e.g., filament deposition, dripping, and the like. The composition may be brought to a particular temperature before deposition. An article may be made by, e.g., layers from a thermoplastic material such as string of pellets or filament from a digital model by selectively dispensing through a nozzle or orifice. For example, the extruded material article can be made by laying down a plastic filament or string of pellets that is unwound from a coil or is deposited from an extrusion head. These additive manufacturing techniques include fused deposition modeling and fused filament fabrication as well as other material extrusion technologies as defined by ASTM F2792-12a.

[0060] Aspect 2. The method of aspect 1 , wherein the thermoplastic compositions comprise one or more polyetherimide oligomers. Polyetherimide (PEI) is considered an especially suitable thermoplastic. Ultem™ PEI by SABIC is considered especially suitable, but other PEI compositions may be used.

[0061] Aspect 3. The method of any of aspects 1 or 2, wherein the first and second populations differ in weight-average molecular weight by from about 2 kDa to about 50 kDa, as determined by GPC relative to polystyrene standards.

[0062] Aspect 4. The method of any of aspects 1-3, wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from about 100: 1 to about 1 : 100. The ratio may also be from about 95:5 to about 5 :95, or from about 90: 10 to about 10:90, or from about 85 : 15 to about 15 : 85, or from about 80:20 to about 20: 80, or from about 30:70 to about 70: 30, or from about 35 :65 to about 65:35, or from about 60:40 to about 40:60, or from about 55:45 to about 45 :55, or about 50:50.

[0063] Aspect 5. The method of aspect 4, wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from 10: 1 to 1 : 10.

[0064] Aspect 6. The method of any of aspects 1 -5, wherein the depositing is performed according to a preset pattern. A preset pattern may be determined from a three- dimensional digital representation of the desired article as is known in the art. As one example, a user may create a digital representation of a desired article by performing a 3-D scan of the article. A user may also construct the 3-D representation of the article ab initio, i.e., based on the user's own needs. For example, a user may construct a 3-D representation of a casing based on the dimensions of the item to be disposed within the casing. [0065] Aspect 7. An article, comprising: at least first and second amounts of thermoplastic composition fused together at a fused region, wherein the thermoplastic composition comprises at least first and second populations of polyetherimide, the at least two or more populations differing in weight-average molecular weight by up to about 100 kDa, as determined by GPC relative to polystyrene standards.

[0066] The fused region may be the interface between first and second layers. An article may include one, two, or more fused regions. A fused region may be an overlap between the first and second amounts of thermoplastic composition. The overlap region may be square or otherwise polygonal in shape. The fusion may be at individual locations, but may also be in lines, seams, or other more continuous shapes. The two amounts may be fused along the entirety of their overlap, but may also be fused at discrete, individual regions along the overlap.

[0067] The two amounts may be disposed such that the fusion occurs concurrently with the deposition of the second amount. A user may also apply additional energy (e.g., via infrared source, via microwave source, via forced air, via convection, or via other methods known to those of skill in the art) following deposition so as to encourage further fusion of the two amounts.

[0068] Aspect 8. The article of aspect 7, wherein the first and second populations differ in weight-average molecular weight by from about 2 kDa to about 60 kDa, as determined by GPC relative to polystyrene standards. The first and second populations may differ in molecular weight by, e.g., from about 10 to about 90 kDa, or from about 15 to about 85 kDa, or from about 20 to about 80 kDa, or from about 25 to about 75 kDa, or from about 30 to about 65 kDa, or from about 35 to about 60 kDa, or from about 40 to about 65 kDa, or from about 45 to about 60 kDa, or from about 50 to about 55 kDa. Populations that differ in molecular weight by from about 10 to about 25 kDa (e.g., from about 15 kDa to about 24 kDa) are considered especially suitable.

[0069] Aspect 9. The article of aspect 8, wherein the article comprises a

polyetherimide oligomer. As described elsewhere herein, Ultem™ is considered especially suitable. Neat PEI or PEI blended with other materials is considered suitable.

[0070] Aspect 10. The article of any of articles 7-9, wherein at least one of the first and second amounts is characterized as a layer. As used herein, "layer" is a term of convenience that includes any shape, regular or irregular, having at least a predetermined thickness. In some embodiments, the size and configuration two dimensions are predetermined, and on some embodiments, the size and shape of all three dimensions of the layer is predetermined. [0071] The thickness of each layer can vary widely depending on the additive manufacturing method and particle size. In some embodiments the thickness of each layer as formed differs from a previous or subsequent layer. In some embodiments, the thickness of each layer is the same. In some embodiments the thickness of each layer as formed is 50 micrometers (microns) to 500 micrometers (microns).

[0072] Aspect 11. The article of any of aspects 7-10, wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from 100: 1 to 1 : 100. The ratio may also be from about 95 :5 to about 5 :95, or from about 90: 10 to about 10:90, or from about 85: 15 to about 15 : 85, or from about 80:20 to about 20: 80, or from about 30:70 to about 70:30, or from about 35 :65 to about 65 :35, or from about 60:40 to about 40:60, or from about 55 :45 to about 45: 55, or about 50:50.

[0073] Aspect 12. The article of aspect 11 , wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from 10: 1 to 1 : 10.

[0074] Aspect 13. The article of any of aspects 7-12, wherein the article is

characterized as being one or more of an aircraft component, a medical device, a tray, a container, a laboratory tool, a food- or beverage-service article, an automotive component, a construction article, a medical implant, a housing, a connector, an ornament, or any combination thereof.

[0075] Some illustrative applications include, without limitation, food service, medical, lighting, lenses, sight glasses, windows, enclosures, safety shields, cookware, medical devices, trays, plates, handles, helmets, animal cages, electrical connectors, enclosures for electrical equipment, engine parts, automotive engine parts, lighting sockets and reflectors, electric motor parts, power distribution equipment, communication equipment, computers, and the like, including devices that have molded in snap fit connectors. Other articles include, for example, hollow fibers, hollow tubes, fibers, sheets, films, multilayer sheets, multilayer films, molded parts, extruded profiles, coated parts, foams, windows, luggage racks, wall panels, chair parts, lighting panels, diffusers, shades, partitions, lenses, skylights, lighting devices, reflectors, ductwork, cable trays, conduits, pipes, cable ties, wire coatings, electrical connectors, air handling devices, ventilators, louvers, insulation, bins, storage containers, doors, hinges, handles, sinks, mirror housing, mirrors, toilet seats, hangers, coat hooks, shelving, ladders, hand rails, steps, carts, trays, cookware, food service equipment, communications equipment and instrument panels, and combinations of these. [0076] Aspect 14. The article of any of aspects 7-13, wherein the thermoplastic composition has a Tg, measured by DSC, in the range of from about 175 to about 235 deg. C. The composition may also have a Tg (measured as described) in the range of from about 215 deg. C. to about 221 deg. C.

[0077] Aspect 15. The article of any of aspects 7-14, wherein the article exhibits one or more of interlay er adhesion, include tensile modulus, fiexural modulus, and elongation at break, that are improved over a corresponding article formed from a single population of

polyetherimide.

[0078] Aspect 16. A method of forming an article, comprising: depositing a plurality of portions of a molten thermoplastic composition that comprises at least first and second populations of polyetherimide that differ by weight-average molecular weight as determined by GPC relative to polystyrene standards, the depositing being performed such that at least some of the plurality of portions of the thermoplastic composition are fused together so as to form the article.

[0079] Suitable polyetheimide compositions are described elsewhere herein. As described elsewhere herein, the populations may differ in molecular weight by, e.g., from about 1 to about 90 kDa, or from about 15 to about 85 kDa, or from about 20 to about 80 kDa, or from about 25 to about 75 kDa, or from about 30 to about 65 kDa, or from about 35 to about 60 kDa, or from about 40 to about 65 kDa, or from about 45 to about 60 kDa, or from about 50 to about 55 kDa. Populations that differ in molecular weight by from about 10 to about 25 kDa (e.g., from about 15 kDa to about 24 kDa) are considered especially suitable.

[0080] Aspect 17. The method of aspect 16, wherein the thermoplastic composition is deposited from a dispenser region (e.g., a nozzle) having a temperature of from about 300 to about 400 deg. C. The temperature may be from about 330 to about 370 deg. C, or even from about 340 to about 360 deg. C.

[0081] Aspect 18. The method of any of aspects 16-17, wherein the lowest molecular weight population of polyetherimides has a weight-average molecular weight of from about 10 kDa to about 50 kDa.

[0082] Aspect 19. The method of any of aspects 16-18, wherein the thermoplastic compositions has a Tg, measured by DSC, in the range of from about 190 to about 230 deg. C, or from about 200 to about 220 deg. C, or even about 210 deg. C.

[0083] Aspect 20. The method of any of aspects 16-19, wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from 100: 1 to 1 : 100. The ratio may also be from about 95:5 to about 5:95, or from about 90: 10 to about 10:90, or from about 85: 15 to about 15:85, or from about 80:20 to about 20:80, or from about 30:70 to about 70:30, or from about 35:65 to about 65:35, or from about 60:40 to about 40:60, or from about 55:45 to about 45:55, or about 50:50.

[0084] Aspect 21. The article or methods of any of aspects 1-21, wherein the thermoplastic compositions comprises a multimodal distribution of weight-average molecular weight. The distribution thus suitably includes two or more modes.

[0085] Aspect 22. The article or methods of aspect 21, wherein the multimodal distribution comprises a bimodal distribution.

[0086] Aspect 23. The article or methods of aspect 21, wherein the multimodal distribution comprises a bimodal distribution.

[0087] Aspect 24. The article or methods of aspect 21, wherein at least two modes are separated by from about 2 to about 70 kDa, or from about 5 to about 60 kDa, or from about 7 to about 47 kDa, or from about 9 to about 39 kDa, or from about 11 to about 33 kDa, or from about 13 to about 29 kDa, or from about 15 to about 26 kDa, or from about 15 to about 21 kDa, or from about 17 to about 19 kDa.

[0088] Aspect 25. The article or methods of aspect 21, wherein the lowest mode has a weight-average molecular weight of between about 20 and about 40 kDa. Lowest modes of about 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 21, 32, 33, 34, 35, 36, 37, 38, and 39 kDa (and all intermediate values) are all considered suitable.

[0089] Aspect 26. The article or methods of aspect 21, wherein the highest mode has a weight-average molecular weight of between about 35 and about 70 kDa. Highest modes of about 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, and 69 kDa (and all intermediate values) are all considered suitable.

[0090] Aspect 27. A method of forming an article, comprising: depositing at least first and second amounts (e.g., layers, lands) of a molten thermoplastic composition that comprises polyetherimide such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article. As described elsewhere, fusing the amounts of the composition may be accomplished by heating, pressure, and the like.

[0091] Aspect 28. The method of aspect 27, wherein thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the lower 50% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having weight-average molecular weights of from about 40 kDa to about 8 kDa, about 5 kDa, about 3 kDa, or even about 2 kDa, or even about 50 times the weight of a PEI monomer unit.

[0092] By "chain weight" is meant the weight-average molecular weight of a given chain. For example, in a sample of chains having weight-average molecular weights 10 kDa, 15 kDa, 20 kDa, 70 kDa, 75 kDa, and 80 kDa, the lower 50% of the sample, by chain weight, comprises polyetherimide chains having molecular weights of 20 kDa or less.

[0093] By "up to the lower x%" is meant the xth percentile or less. For example, "up to 25%" means 25% or less.

[0094] Aspect 29. The method of aspect 28, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the lower 40% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 15 kDa.

[0095] Aspect 30. The method of aspect 29, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the lower 30% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 15 kDa.

[0096] Aspect 31. The method of aspect 30, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the lower 20% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 15 kDa.

[0097] Aspect 32. The method of aspect 31 , wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the lower 10% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 15 kDa.

[0098] Aspect 33. The method of aspect 27, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the upper 99.9% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 1 10 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa.

[0099] By "up to the upper x%" is meant from the [100-x]th percentile up to the 100th percentile. For example, in a sample of chains having weights 10 kDa, 15 kDa, 20 kDa, 70 kDa, and 80 kDa, the upper 80% the sample, by chain weight, comprises the polyetherimide chains having molecular weights of 15 kDa or more.

[00100] Aspect 34. The method of aspect 33, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with the upper 70% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 1 10 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa.

[00101] Aspect 35. The method of aspect 34, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with the upper 60% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 1 10 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa.

[00102] Aspect 36. The method of aspect 35, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with the upper 50% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 1 10 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa.

[00103] Aspect 37. The method of aspect 35, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with the upper 40% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 1 10 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa.

[00104] Aspect 38. The method of aspect 37, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with the upper 30% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 1 10 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa. [00105] Aspect 39. The method of aspect 38, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with the upper 20% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 1 10 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa.

[00106] Aspect 40. The method of aspect 39, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with the upper 10% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 1 10 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa.

[00107] It should be understood that a thermoplastic composition may comprise essentially any distribution of polyetherimide chains. The distribution may be unimodal, bimodal, trimodal, or otherwise multimodal. A distribution may be symmetric (e.g., a traditional bell curve) or even skewed. Bimodal distributions of polyetherimide chains of different weights are especially suitable, but uni- or multimodal distributions are suitable as well.

[00108] A population of polyetherimide may also be defined in terms of averages. For example, the population of polyetherimide in a thermoplastic composition may be such that, by number, up to 50%, up to 40%, up to 30%, up to 20%, or even up to 10% of the polyetherimide chains in a sample have an average chain weight of from about 50 kDa to about 15 kDa.

Similarly, the population of polyetherimide in a thermoplastic composition may be such that, by number, up to 50%, up to 40%, up to 30%, up to 20%, or even up to 10% of the polyetherimide chains in a sample have an average chain weight of from about 40 kDa to about 120 kDa, or from about 50 kDa to about 110 kDa, or from about 60 kDa to about 100 kDa, or from about 70 kDa to about 90 kDa, or even about 80 kDa.

[00109] Aspect 41. An article, comprising: at least first and second amounts of thermoplastic composition fused together at a fused region, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains (a) with up to the lower 50% by chain weight, of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa; (b) with up to the upper 80% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa; or (a) and (b).

[00110] Aspect 42. The article of aspect 41, wherein up to the lower 50% by chain weight, of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa.

[00111] Aspect 43. The article of aspect 41, wherein up to the lower 30% by chain weight, of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa.

[00112] Aspect 44. The article of aspect 41, wherein up to the lower 20% by chain weight, of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa.

[00113] Aspect 45. The article of aspect 42, wherein up to the lower 50% by chain weight, of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 30 kDa to about 20 kDa.

[00114] Aspect 46. The article of aspect 41, wherein up to the upper 80% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa.

[00115] Aspect 47. The article of aspect 46, wherein up to the upper 60% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa.

[00116] Aspect 48. The article of aspect 47, wherein up to the upper 50% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa.

[00117] Aspect 49. The article of aspect 48, wherein up to the upper 30% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa.

[00118] Aspect 50: The article of any of aspects 41-49, wherein the article is characterized as being one or more of an aircraft component, a medical device, a tray, a container, a laboratory tool, a food- or beverage-service article, an automotive component, a construction article, a medical implant, a housing, a connector, an omament, or any combination thereof.

[00119] As further non-limiting examples, articles according to the present disclosure may be, e.g., computer and business machine housings such as housings for monitors, handheld electronic device housings such as housings for cell phones, electrical connectors, and components of lighting fixtures, ornaments, home appliances, roofs, greenhouses, sun rooms, swimming pool enclosures, thin walled articles such as housing for electronic devices and the like. Additional examples of articles that can be formed from the compositions include electrical parts, such as relays, and enclosures, consumer electronics such as enclosures and parts for laptops, desktops, docking stations, personal digital assistants (PDAs), digital cameras, desktops, and telecommunications parts such as parts for base station terminals. Further examples of articles that can be formed from compositions include light guides, light guide panels, lenses, covers, sheets, films, and the like, e.g., LED lenses, LED covers, and so forth.

[00120] The thermoplastic composition of an article may also have a Tg, measured by DSC, in the range of from about 175 to about 235 deg. C. The composition may also have a Tg (measured as described) in the range of from about 215 deg. C. to about 221 deg. C.

[00121] Aspect 51. A method of forming an article, comprising: depositing at least first and second amounts of a molten thermoplastic composition that comprises polyetherimide such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, the thermoplastic composition comprising a plurality of polyetherimide polymer chains, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the upper 99.9% by chain weight of the

polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa,

[00122] In such an article, up to the upper about 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or even about 5% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, The balance of the polyetherimide polymer chains suitably have a molecular weight of less than about 40 kDa, e.g., from about 40 kDa to about 2 kDa and all intermediate values, e.g., from about 30 kDa to about 5 kDa, from 25 kDa to about 10 kDa, and all

[00123] Aspect 52. An article formed by additive manufacturing, the article comprising comprising: depositing at least first and second amounts of a molten thermoplastic composition that comprises polyetherimide such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, the thermoplastic composition comprising a plurality of polyetherimide polymer chains, with up to the lower 50% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa.

[00124] In such an article, up to about 45, 40, 35, 30, 25, 20, 15, 10,5, 4, 3, 2, or even about 1 % by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa,

[00125] As disclosed herein, it should be understood that a bi-, tri-, or other polymodal distribution of molecular weights is not a requirement. As an example, a unimodal (e.g., poly disperse) distribution of molecular weights is also suitable. In some embodiments (both unimodal and polymodal) of the disclosed technology, where so-called light PEI of from about 2 to about 20 kDa is present, the presence of 1 wt% or more of such light PEI is considered suitable, as the relative amount of light PEI increases, the mechanical properties of the final composition may change. The user of ordinary skill will without difficulty arrive at the optimal loading of light PEI to achieve the desired mechanical properties. As one illustrative example, for PEI 3 (described elsewhere herein), 10-15 wt% and above is considered suitable. Adhesion between layers may improve with relatively high levels of light PEI, but other properties may deteriorate below the polymer entanglement molecular weight.

[00126] Thus, in a further aspect, the present disclosure also provides methods, the methods comprising depositing at least first and second amounts of a molten thermoplastic composition such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article. The thermoplastic composition suitably comprises a population of polyetherimide, up to the upper 99.9% by chain weight of the polyetherimide comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa, and the balance comprising polyetherimide chains having molecular weights of less than about 40 kDa.

Claims

What is Claimed:

1. A method of forming an article, comprising: depositing at least first and second amounts of a molten thermoplastic composition such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, wherein the thermoplastic composition comprises at least first and second populations of polyetherimide, the first and second populations differing in weight-average molecular weight by up to about 100 kDa, as determined by gel permeation chromatography (GPC) relative to polystyrene standards.

2. The method of claim 1, wherein the thermoplastic composition comprises one or more polyetherimide oligomers.

3. The method of any one of claims 1 or 2, wherein the first and second populations differ in weight-average molecular weight by from about 2 kDa to about 60 kDa, as determined by GPC relative to polystyrene standards.

4. The method of any one of claims 1-3, wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from 100: 1 to 1 : 100.

5. The method of claim 4, wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from 10: 1 to 1 : 10.

6. The method of any one of claims 1-5, wherein the depositing is performed according to a preset pattern.

7. An article, comprising: at least first and second amounts of thermoplastic composition fused together at a fused region, wherein the thermoplastic composition comprises at least first and second populations of polyetherimide, the at least two or more populations differing in weight-average molecular weight by up to about 100 kDa, as determined by gel permeation chromatography (GPC) relative to polystyrene standards.

8. The article of claim 7, wherein the first and second populations differ in weight-average molecular weight by from about 2 kDa to about 60 kDa, as determined by GPC relative to polystyrene standards.

9. The article of claim 8, wherein the article comprises a polyetherimide oligomer.

10. The article of any one of claims 7-9, wherein at least one of the first and second amounts is characterized as a layer.

1 1. The article of any one of claims 7-10, wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from 100: 1 to 1 : 100.

12. The article of claim 11, wherein the ratio, by weight, of the first population of polyetherimide to the second population of polyetherimide is from 10: 1 to 1 : 10.

13. The article of any one of claims 7-12, wherein the article is characterized as being one or more of an aircraft component, a medical device, a tray, a container, a laboratory tool, a food- or beverage-service article, an automotive component, a construction article, a medical implant, a housing, a connector, an ornament, or any combination thereof.

14. The article of any one of claims 7-13, wherein the thermoplastic composition has a Tg, measured by DSC, in the range of from about 175 to about 235 deg. C.

15. The article of any one of claims 7-14, wherein the article exhibits one or more of interlay er adhesion, tensile modulus, flexural modulus, and elongation at break, that are improved over a corresponding article formed from a single population of polyetherimide.

16. A method of forming an article, comprising: depositing a plurality of portions of a molten thermoplastic composition that comprises at least first and second populations of polyetherimide that differ by weight-average molecular weight as determined by gel permeation chromatography (GPC) relative to polystyrene standards, the depositing being performed such that at least some of the plurality of portions of the thermoplastic composition are fused together so as to form the article.

17. A method of forming an article, comprising: depositing at least first and second amounts of a molten thermoplastic composition that comprises polyetherimide such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, the thermoplastic composition comprising a plurality of polyetherimide polymer chains, with up to the lower 50% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa.

18. A method of forming an article, comprising: depositing at least first and second amounts of a molten thermoplastic composition that comprises polyetherimide such that at least a portion of the first amount fuses to at least a portion of the second amount so as to form a fused region of the article, the thermoplastic composition comprising a plurality of polyetherimide polymer chains, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains, with up to the upper 99.9% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa.

19. An article, comprising: at least first and second amounts of a thermoplastic composition fused together at a fused region, wherein the thermoplastic composition comprises a plurality of polyetherimide polymer chains (a) with up to the lower 50% by chain weight, of the

polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 2 kDa (b) with up to the upper 80% by chain weight of the polyetherimide of the thermoplastic composition comprising polyetherimide polymer chains having molecular weights of from about 40 kDa to about 120 kDa; or (a) and (b).

20. The article of claim 19, wherein up to the lower 50% by chain weight of the polyetherimide of the thermoplastic composition comprises polyetherimide polymer having molecular weights of from about 40 kDa to about 2 kDa.