WO2008083258A1 - Polyimide/copolyimide films with low glass transition temperature for use as hot melt adhesives - Google Patents

Abstract

Poly(amic) acid precursors, polyimide and copolyimide compositions are described which exhibit a low Tg and are useful as adhesives, and optionally containing a diaminoalkyne.

Description

POLYIMIDE/COPOLYIMIDE FILMS WITH LOW GLASS TRANSITION TEMPERATURE FOR USE AS HOT MELT ADHESIVES

BACKGROUND

This application claims benefit of U.S. Provisional Application Nos. 60/882,677 and 60/877,630, which were both filed December 29, 2006, the entire contents of each of which is incorporated herein by reference.

I. TECHNICAL FIELD

[0001] This invention pertains to hot melt adhesives, methods of making such adhesives, and the use of such adhesives in the fabrication of laminated piezoelectric elements or devices, and the laminated piezoelectric devices produced thereby.

II. RELATED ART AND OTHER CONSIDERATIONS

[0002] As is well known, a piezoelectric material is polarized and will produce an electric field when the material changes dimensions as a result of an imposed mechanical force. This phenomenon is known as the piezoelectric effect. Conversely, an applied electric field can cause a piezoelectric material to change dimensions.

[0003] A laminated piezoelectric actuator is manufactured by bonding (e.g., by using adhesive or other means) one or more piezoelectric ceramic wafer(s) or element(s) to a substrate(s). One purpose of bonding the piezoelectric ceramic to the substrate is to maintain partial compressive load on the ceramic element such that when it is energized, it does not fracture under tension. A common substrate material is metal, often stainless steel, although other metals can also be used.

[0004] One type of laminated piezoelectric element is known as a ruggedized laminated piezoelectric or RLP^®, which has a piezoelectric wafer which is laminated to a stainless steel substrate and preferably also has a beryllium copper cover laminated thereover. Examples of such RLP^® elements, and in some instances pumps employing the same, are illustrated and described in one or more of the following: PCT Patent Application PCT/US01 /28947, filed 14 September 2001 ;

United States Patent Application Serial Number 10/380,547, filed March 17, 2003, entitled "Piezoelectric Actuator and Pump Using Same"; United States Patent Application Serial Number 10/380,589, filed March 17, 2003, entitled "Piezoelectric Actuator and Pump Using Same", and United States Patent Application 11/279,647 filed April 13, 2006, entitled "PIEZOELECTRIC DIAPHRAGM ASSEMBLY WITH CONDUCTORS ON FLEXIBLE FILM", all of which are incorporated herein by reference.

[0005] The bonding or lamination of a piezoelectric element such as a piezoelectric ceramic wafer to a substrate or other metallic layer can be performed using a hot melt adhesive. Bonding or lamination using a hot melt adhesive (including a polyimide adhesive such as that known as LaRC-SI™) is taught by one or more of the following United States patent documents (all of which are incorporated herein by reference: US Patent Publication US 2004/0117960 A1 to Kelley; US Patent 6,512,323 to Forck et al.; US Patent 5,849,125 to Clark; US Patent 6,030,480 to Face; US Patent 6,156,145 to Clark; US Patent 6,257,293 to Face; US Patent 5,632,841 to Hellbaum; US Patent 6,734,603 to Hellbaum; and US Patent 5,639,850 to Bryant. The entire contents of each of these documents is incorporated in their entirety herein.

[0006] Polyimide and its precursor are prepared by reacting a diamine with a dianhydride. Typically, polyimides with excellent solvent resistance and thermal and mechanical stability possess aromatic structure in their backbone which usually produces high Tg. What is needed, however, and an object of the present invention, are polyimide (Pl) and/or copolyimide (CPI) films with low glass transition temperature (Tg) for use as a hot melt adhesive for, e.g., piezoelectric element lamination methods and processes.

[0007] Moreover, the curing of the hot melt adhesive occurs at fairly high temperatures. What is needed, however, and a further advantage of example embodiments, is a method of making a hot melt adhesive which does not require the typically high temperature for adhesive curing, which has a controllable amount of cross-linking introduced, and which imparts a thermosetting property to the adhesive, as well as the adhesives produced thereby, and optionally the use of such adhesives for making laminated piezoelectric elements. BRIEF SUMMARY

[0008] Polyimide (Pl) and/or copolyimide (CPI) films with reduced glass transition temperature (Tg) are prepared from the low cost commercially available monomers by including both aromatic and aliphatic/ether functional groups in the polymer backbone. The resultant polyimide (Pl) and/or copolyimide (CPI) films result in a softening/flow temperature (i.e., Tg) lower than comparable adhesive polyimides (for example, LaRC-SI). The resultant low Tg films, as described herein, also have good solubility, suitable thermal and mechanical properties for use in processes of laminating piezoelectric wafers or layers to other layers such as substrates. These combinatorial properties allow for the low Tg polyimide Pl materials disclosed herein to create desired stress-biasing within an actuator, for instance placing a ceramic PZT layer in partial compression in a multilayer actuator, as well as general strong adhesive bonds between substrates, with less aggressive thermal cycles than would be necessary with previously available polyimide adhesives (for example, LaRC-SI).

[0009] In one embodiment, the present technology provides a method of making a copolyimide as an adhesive film using a diaminodialkyne substituent, such as a diacetylene-containing monomer; as a latent cross-linking moiety, with the copolyimide to form a poly(amic acid) solution; casting the poly(amic acid) solution into a film; and curing the film. The inclusion of the latent cross-linking moiety, or combination of such moieties, allows for cross-linking of the polyimide or copolyimide adhesive of the present technology in situ, such as after assembly of a piezoelectric wafer containing assembly or subassembly.

[0010] The poly(amic) acid and/or polyimide and copolyimide of the present technology may further include dopants or additives, such as aromatic and/or non- aromatic epoxides, which form a cross-linked polymer network which is not part of the polymer polyimide and/or copolyimide described herein.

[0011] A method of making a laminated piezoelectric element comprises applying an adhesive containing a diacetylene-containing monomer between a piezoelectric layer and a substrate layer, and then curing the adhesive, such as by individual or combination of thermal and/or chemical imidization and/or cross-linking.

In one embodiment, the poly(amic) acid is imidized prior to assembly of the piezoelectoc containing device and the polyimide and/or copolyimide is cross-linked during lamination of the device. [0012] Diacetylene-containing monomers used in the present technology include monomers having diacetylene groups within a linear polymer chain. For example, in one example mode the diactylene-containing monomer is 1 ,4-Bis(3- aminophenyl)butadiyne and/or 3-(4-(3-aminophenyl)buta-1 ,3-diynyl)benzenamine. In a representative, generic mode, the diacetylene-containing monomer has a structure generically represented as

, wherein R may be represented as CR'R"(CH₂)_nNH_2, wherein R' and R" are each individually H or CrC₆ straight or branched alkyl and n is an integer from 1 -60, optionally from 1 -50, 1-40, 1-

30, 1 -20, 2-20, 5-20, 1 -15, 2-15, 5-15, 1 -10, 2-10, or 5-10; or

or

(wherein m is an integer from 1 -75, optionally from

1 -50, such as from 1 -30, 2-20 or 1 -15).

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of preferred embodiments as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

[0014] Fig. 1 shows a general scheme for polyimide synthesis according to an example mode.

[0015] Fig. 2 shows structure of a dianhydride compound abbreviated as UDA.

[0016] Fig. 3 shows structure of a diamine compound abbreviated as 3,4'-BAPS.

[0017] Fig. 4 shows structure of a diamine compound abbreviated as 4,4'-BAPS. [0018] Fig. 5 shows structure of a diamine compound abbreviated as 3,4'-PDPB.

[0019] Fig. 6 shows structure of a diamine compound abbreviated as 4,4'-PDPB.

[0020] Fig. 7 shows structure of a crosslinker compound abbreviated as X-Linker.

[0021] Fig. 8 shows structure of a compound abbreviated as ER.

[0022] Fig. 9 shows structure of a compound abbreviated as EPAr.

[0023] Fig. 10 shows structure of a compound abbreviated as PE.

[0024] Fig. 11 shows structure of a compound abbreviated as Triacrylate.

[0025] Fig. 12 shows structure of a UlinkerAC trimer wherein Ar may be a substituted or unsubstituted aryl or aryl-containing subunits.

DETAILED DESCRIPTION

[0026] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. In some instances, detailed descriptions of well- known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. All statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

[0027] Thermal imidization is a process wherein poly(amic acid) solution is converted to polyimide through a thermal process of closing the aromatic ring, a reaction that releases H₂O as a byproduct. Polyimides mentioned in this disclosure can be either partially or fully thermally imidized with a peak imidization temperature ranging from 140° C to 350° C. Cycle time for thermal imidization depends on heating methods, heating equipment, and the desired completeness of imidization and/or solvent removal from poly(amic acid) solution and can range from on the order of 30s to a multiple hour thermal treatment to complete a full thermal treatment process..

[0028] A precursor to polyimide, poly(amic acid), can exist within a solution of a given solvent (for example, 20 wt% PAA in n-methylpyrollidinone). Thermal processing of the PAA results in a "solidified" polymer through imidization of the PAA and evaporation of a certain portion of the solvent contained within the initial PAA solution. For the purposes of producing an optimum adhesive during subsequent heating operations ("bonding"), it may be desirable during the thermal imidization to have a slight amount of solvent remaining in the resultant film or solid polymer product, for example between 0 to 10%, or 0 to 8 wt%, such as 0.2% to 10.0%, 0.2%-2%, 2%-4%, 0.2%-7%, 5%-7%, 0.2%-4%, or 4%-10% (as measured by retained volatilities wherein the % is the weight % of solvent remaining in the imide as measured using TGA as described herein). A solidified polymer demonstrating this level of retained solvent will typically flow more at a given second heating temperature than the same polyimide structure with less retained solvent present, and thereby may act as an adhesive at lower temperatures and/or process cycle times.

[0029] An alternative to thermal imidization is chemical imidization to produce a polyimide structure. All of the polyimides mentioned in this disclosure can be chemically imidized by methods well known in the art. Upon chemical imidization, resulting polymers can be used in solution form or in solid form to either produce film product or to perform subsequent bonding operations, for example adding polyimide shreds to a substrate and heating the shreds to an elevated temperature such that they bond to the substrate.

[0030] Polyimide (Pl) and/or copolyimide (CPI) films with reduced glass transition temperature (Tg) are prepared from the low cost commercially available monomers by including both aromatic and aliphatic/ether functional groups in the polymer backbone. The resultant polyimide (Pl) and/or copolyimide (CPI) films result in a softening/flow temperature (i.e., Tg) lower than comparable adhesive polyimides (for example, LaRC-SI (Langley Research Center - Soluble Imide) is an amorphous thermoplastic). The resultant low Tg films, as described herein, also have good solubility, suitable thermal and mechanical properties for use in processes of laminating piezoelectric wafers or layers to other layers such as substrates. These combinatorial properties allow for the low Tg polyimide (Pl) materials disclosed herein to create desired stress-biasing within an actuator, for instance placing a ceramic PZT layer in partial compression in a multilayer actuator, as well as general strong adhesive bonds between substrates, with less aggressive thermal cycles than would be necessary with previously available polyimide adhesives (for example, LaRC-SI)-A general scheme for polyimide synthesis according to an example embodiment and mode is shown in Fig. 1.

[0031] The poly(amic) acids or polyimide or copolyimide of an example embodiment may have acid anhydride groups in the skeleton which are the reaction product of an acid anhydride having a functionality of at least 2 with an amine having a functionality of at least 2. The molar ratio of amine/acid anhydride ranges, in one example embodiment, from 0.9:1.0 to 1.1 :1.0.

[0032] The polyimide resin used herein is obtained by reacting a di- or more functional amine component, such as difunctional amine component with a di- or more functional acid anhydride component.

[0033] The di- or more functional acid anhydride component used in the preparation of the poly(amic) acids or polyimide or copolyimide may include, for example, pyromellitic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 2,3,3',4'- biphenyltetracarboxylic acid, bis(3,4-carboxyphenyl)sulfone, 3,3',4,4'- biphenyltetracarboxylic acid, bis[4-(3,4-dicarboxyphenoxy)phenyl]-methane, bis[4- (3,4-dicarboxyphenoxy)phenyl]-ethane, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]- propane, bis(3,4-dicarboxyphenyl)difluoromethane, 2,2-bis(3,4- dicarboxyphenyl)hexafluoropropane, 1 ,3-bis(3,4-dicarboxyphenyl)-1 ,1 ,3,3- tetramethylsiloxane, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane, bis(3,4- dicarboxyphenyl)ether, and reactive derivatives of the foregoing such as dianhydrides and esters, alone or in admixture of any.

[0034] In one example embodiment, a dianhydride of the poly(amic) acids or polyimide or copolyimide may be of the following formula (1 ):

[0036] wherein Qi and Q2 may the same or different and Ji and J₂ may the same or different. Qi and Q2 of formula (1 ) may be -O- or -S- or a straight or branched, substituted or unsubstituted, CrC₆alkyl containing -O- or -S- in the alkyl chain containing Q₁, Q₂, A, J₁ and J₂ of formula (1 ). J₁ and J₂ of formula (1 ) may be substituted or unsubstituted C₅-C₁₄ aryl, C₅-C₁₄ cycloalkyl, C₅-C₁₄ cycloalkylaryl, including fused cyclic or aryl rings, such as a mono-, bi-, or tricyclic, aryl (such as containing at least one unsaturation) or carbocyclic ring, such as a 5, 6, 7 or 8 membered rings, wherein the ring is either unsubstituted or substituted in, for example, one to five position(s) with simple substitutions, such as halo, haloalkyl, hydroxyl, nitro, trifluoromethyl, C₁-C₁₀ straight or branched chain alkyl; wherein the individual ring sizes are preferably 5-8 members. Aryl may include include but are not limited to phenyl, benzyl, and naphthyl. A in formula (1 ) may be the same as Q₁ or Q₂. The values of r and s in formula (1 ) may be independently 1 , 2, 3, 4 or 5. Further, Q₁ or Q₂ may be symmetric or asymetircally substituted around the

substitutions of the

structures of formula (1 ).

[0037] In one example embodiment, Q₁ and Q₂ in formula (1 ) are -O- and J₁ and J₂

are

, and A is -S- or a straight or branched, unsubstituted, Ci-C₆alkyl, and r and s are as defined above. [0038] In one example embodiment, Qi and Q2 in formula (1 ) are -O- and Ji and J₂

are

, and A is -S- or branched, unsubstituted, Ci-Cβalkyl and r and s are as defined above.

[0039] In one example embodiment, Qi and Q2 in formula (1 ) are -O- and Ji and J2

are

, and A is -S- or branched, unsubstituted, Ci-Cβalkyl and r and s are as defined above.

[0040] In one example embodiment, Qi and Q2 in formula (1 ) are -O- and Ji and J2

are

, and A is -S- or branched, unsubstituted, Ci-Cβalkyl and r or s is 1 the other of r and s is as defined above.

[0041] In one example embodiment, Q₁ and Q₂ in formula (1 ) are -O- and Ji and J₂

are

and A is -S- or branched, unsubstituted, Ci-Cβalkyl and r and s are 1.

[0042] Dianhydrides according to the present technology may include at least one of the following: BDPSA, PMDA, BPDA, ODPA, UDA and BDA1 , as described herein.

[0043] Poly(amic) acids and/or polyimides and/or copolyimides according to the present technology may include, in one embodiment, at least UDA as a sole or one of multiple dianhydride monomers or moieties.

[0044] The di- or more functional amine component used in the preparation of the poly(amic) acids and/or polyimide and/or copolyimide described herein may include, for example, 4,4'-diaminodiphenylnnethane, o-, m-or p-phenylenediamine, bis(4-(3- aminophenoxy)phenyl)-sulfone, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4- diaminoxylene, 2,4-diaminodurene, dimethyl-4,4'-dianninodiphenyl, dialkyl-4,4'- diaminodiphenyls, dimethoxy-4,4'-dianninodiphenyl, diethoxy-4,4'-diaminodiphenyl, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 3,3'- diaminobenzophenone, 1 ,3-bis(3-aminophenoxy)benzene, 1 ,3-bis(4- aminophenoxy)benzene, 1 ,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4- aminophenoxy)-biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2'-bis(4-(4- aminophenoxy)phenyl)propane, 2,2-bis(4-(4- aminophenoxy)phenylhexafluoropropane, 2,2-bis(4-(3- aminophenoxy)phenyl)propane, 2,2-bis(4-(3- aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-(4-amino-2- trifluoromethylphenoxy)phenyl)hexafluoropropane, 2,2-bis(4-(3-amino-5- trifluoromethylphenoxy)-phenyl)hexafluoropropane, 2,2-bis(4- aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2- bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3-amino-4- methylphenyl)hexafluoropropane, 4,4'-bis(4-aminophenoxy)octafluorobiphenyl, 2,2'- bis(trifluoromethyl)diaminodiphenyl, 3,5-diaminobenzotrifluoride, 2,5- diaminobenzotrifluoride, 3,3'-bistrifluoromethyl-4,4'-dianninobiphenyl, 3,3'- bistrifluoromethyl-5,5'-dianninobiphenyl, bis(trifluoromethyl)-4,4'-dianninodiphenyl, bis(fluorinated alkyl)-4,4'-diaminodiphenyls, dichloro-4,4'-diaminodiphenyl, dibromo- 4,4'-diaminodiphenyl, bis(fluorinated alkoxy)-4,4'-diaminodiphenyls, diphenyl-4,4'- diaminodiphenyl, 4,4'-bis(4-aminotetrafluorophenoxy)tetrafluorobenzene, 4,4'-bis(4- aminotetrafluorophenoxy)octafluorobiphenyl, 4,4'-bisnaphthylamine, 4,4'- diaminobenzanilide, 4,4'-diamino(N-alkyl)benzanilides, alone or in admixture of any.

[0045] Diamines of the poly(amic) acids and/or polyimides and/or copolyimides of the present technology may include at least one of the following: PMDA, ODA, 3,4'-ODA, 3,4'-BAPS, 4,4'-BAPS, 3,4'-PDPB, 4,4'- PDPB, 1 ,4-Bis(3-aminophenyl)butadiyne, 3- (4-(3-aminophenyl)buta-1 ,3-diynyl)benzenamine, and diaminodialkynes of formula

(2) as described herein.

[0046] Poly(amic) acids and/or polyimides and/or copolyimides according to the present technology may include, in one embodiment, at least 3,4 PDPB as a sole or one of multiple diamine monomers or moieties. [0047] Adhesive films of the present technology may have a thickness of 5 to 500 μm and be in the form of sheets.

[0048] The polyimide (Pl) and/or copolyimide (CPI) films and/or adhesives of the present technology are able to be processed after the first stage of the reaction, such as after the formation of poly(amic) acid, remaining soluble in the final form and not requiring further chemical processing to produce final articles, such as thin films, adhesive films, varnishes, etc. The polyimide and/or copolyimide of the present technology can be used to laminate and/or bond metals and/or ceramics using, for example, application of temperature and pressure or thermal load and pressure load.

[0049] As noted above, the present technology further provides polyimide compositions wherein a cross linker, such as at least one diaminoalkyne, such as a diacetylene-containing compound, is included.

[0050] Hot melt adhesives (such as polyimide adhesives), and films formed from hot melt adhesives, have been utilized to laminate piezoelectric wafers or layers to one or more metallic layers, such as a substrate. Yet bonds formed from hot melt adhesives tend to fail when the adhesive flows (as a result, e.g., of elevated temperature). It has been determined, however, that bonds (e.g., between a piezoelectric layer and a substrate) formed with polyimide film that is (preferably lightly) crosslinked can retain their strength to higher temperature than those formed with structurally similar but linear polyimide. Accordingly, herein described are methods of making a thermosetting polymer film that can be used as a hot melt adhesive and which is less susceptible to bond failure.

[0051] Diaminoalkyne or Diacetylene-containing polyimides described herein have been found to be of appropriate reactivity to permit preparation of linear polyimide films that undergo intermolecular reactions to produce lightly crosslinked polyimide during lamination of a piezoelectric layer and a substrate. Also described herein are methods of making an adhesive or film comprising at least one diacetylene- containing monomer, as well as film(s) and adhesive(s) containing the same. Also described herein are methods of making a laminated piezoelectric element which comprise applying an adhesive containing a diacetylene-containing monomer between a piezoelectric layer and a substrate layer, and then curing the adhesive, as well as the laminated piezoelectric elements formed by such methods. Preferably the adhesive comprises a diacetylene-containing monomer having diactylene groups within a linear polymer chain.

[0052] For example, the diaminodialkyne or diactylene-containing monomer may be 1 ,4-Bis(3-aminophenyl)butadiyne, having the structure illustrated in Table 1. The diaminodialkyne or diacetylene-containing monomer may further have the following structure of formula (2)

[0053] :

[0054] wherein each R, which may be the same or different, may be represented as

CR'R"(CH₂)nNH₂,,

, wherein R' and R" are each individually H or CrC₆ straight or branched alkyl and n is an integer from 1 -60, optionally from 1 -50, 1 -40, 1 -30, 1 -20, 2-20, 5-20, 1 -15, 2-15, 5-15, 1 -10, 2-10, or 5-10; and m is an integer from 1 -75, optionally from 1 -50, such as from 1 - 30, 1 -6, 2-20, 2-6 or 1 -15. The -NH₂ may be substituted around the ring in different

positions where both R are selected from

or

, such as at meta positions. Mixed structures are useful in the present technology, such as cross-linkers containing a mixture or prepared as a polymer and/or pre-polymer of a dianhydhde monomer according to the present technology and a diacetylene-containing monomer according to the present technology. The Ci-C₆ alkyls include methyl, ethyl, propyl, butyl, hetyl and hexyl. [0055] The poly(amic) acid and/or polyimide and/or copolyimide may include at least one dianhydhde, at least one diamine and at least one cross-linking moiety, such as the diaminodialkynes, described herein, in the linear chain of the poly(amic) acid and/or polyimide and/or copolyimide.

[0056] The poly(amic) acid and/or polyimide and/or copolyimide of a further embodiment may include at least one a dopant and/or additive, such as are described herein, in addition to the at least one dianhydride, at least one diamine and, optionally, at least one cross-linking moiety, such as the diaminodialkynes, described herein. An exemplified dopant/additive, Triacrylate (Tri) is Thmethylolpropane ethoxylate triacrylate ((such as 14/3 EO/OH) molecular weight of M_n 912 g/mol) - Sigma-Aldrich Catalog No. 28961 -43-5

, subscripts definition dependent on molecular weight of product and not specified herein (2007); CAS Number 28961 -43-5 ; MDL number MFCD00074919 ). Thacrylates, for example, may be included as a multifunctional additive with total content in copolyimide between 0.25 and 15.0 molar percent (for example, a UDA/3,4'-PDPB copolyimide with 4.8% triacrylate additive) and used with primary function of lowering Tg and/or increasing adhesive strength. Diacrylates,

such as poly(ethyleneglycol) diacrylate (Aldrich 437441 subscripts definition dependent on molecular weight of product and not specified herein (2007) (CAS Number 26570-48-9), mol wt average Mn -575). Tetraacrylates and pentaacrylate additives may be similarly included in the formulations (poly(amic) acid and/or polyimide and/or copolyimide).

[0057] Table 1 provides an exemplification of dopants and/or additives of the present technology. Epoxides, such as those exemplified in Table 1 , may include multiple aryl and/or alkyl repeating units of the sort exemplified in the compounds of Table 1. Moreover, biacrylates and triacrylates, such as is exemplified in Table 1 are contemplated. [0058] Further dopants and/or additives which may be included in the poly(amic) acid and/or polyimides and/or copolyimides include, the following:

[0059] Thmethoxysilane, for example, may be used as an end capper to limit chain growth and therefore molecular weight.

[0060] "Trisazihdine": For example, Trimethylolpropane tris (2-methyl-1 -aziridine propionate) Aldrich # 405442 (2007) (CAS Number 64265-57-2

)(

), 467g/mol used as a dopant for making a cross-linked network.

[0061] Polydimethylsiloxane (PDMS): For example, 2500 g/mol, Aldrich # 481688 CAS Number 106214-84-0

( , subscripts definition dependent on molecular weight of product and not specified herein.)

[0062] Siloxane End Groups: For example, (MeO)₃Si.

[0063] Poly(butanediol):For example, Aldrich 426598 (2007) (CAS Number 54667-

43-5 ) , Mn ~470 (x=3-4) via

NMR indicating 3.62 repeat units on average.

[0064] In one example embodiment, the poly(amic) acid, polyimide and/or copolyimide of the present invention, as otherwise described herein, does not include photosensitive groups and/or photoinitiators. [0065] In one example embodiment, the poly(amic) acid, polyimide and/or copolyimide of the present invention, as otherwise described herein, does not include photosensitive groups and/or photoinitiators.

[0066] In one example embodiment, the poly(amic) acid, polyimide and/or copolyimide, as otherwise described herein, does not include photoinitiators, such as Michler's ketone, benzoin, 2,6-bis(4-azidobenzylidene)4-methyl-cyclohexanone and its derivatives, benzil, 2,3-butanedione, 4,4-dimethoxy benzoin, substituted thioxanthones, such as 2-propoxy thioxanthone 2,2-dimethoxy-2- phenylacetophenone, benzoin ethyl ether, benzoin isopropyl ether, benzoin methyl ether, and 2-(n-butoxy) ethyl-4 dimethylaminobenzoate; or photosensitizers for radical transfer are N-phenyldiethanolamine, 2-methoxy ethanol, N-phenyl- ethanolamine, N-phenyl-N-methylethanolamine, and N-phenyl-N-ethylethanolamine.

[0067] The polyimide and/or copolyimide in one example embodiment has a Tg, as measured by the method described herein in the range of about 120° - 220°C.

[0068] The present technology further provides a substrate, such a stainless steel substrate or a beryllium copper substrate, at least partially coated or wholly coated on at least one surface with a poly(amic) acid, polyimide and/or copolyimide of the present technology. The substrate may be at least partially coated or wholly coated on one surface, with a cast film of a polyimide and/or copolyimide of the present technology. The at least partially or wholly coated substrate may be part of a multilayered and/or multicomponent and/or multi-layered structure wherein at least one of the components and/or layers may be at least partially and/or wholly coated with a poly(amic) acid, polyimide and/or copolyimide of the present technology.

[0069] Further substrates include at least one of aluminum, its alloys, and associated oxides; silver, its alloys, and associated oxides as well as silver paste with one or more additives such as glass frit or ceramic particles; gold, its alloys, and associated oxides; chromium, its alloys, and associated oxides; copper, its alloys (for example: Beryllium Copper, Bronze, Phosphorus Bronze) and associated oxides; Nickel, its alloys (for example, Nickel Vanadium and Nickel Chromium), and associated oxides; and any combination of metallization layers described herein, for example a gold metallization deposited on a base chromium or nickel chromium metallization. Further substrates include, for example, Carbon Steel, for example steels containing carbon content between 0.01 % and 10.0%, and its associated oxides and alloys; Sintered, pressed, hot pressed, vacuum pressed, isostatically pressed, or as-fired ceramics such as a PZT (lead zirconium titanate) ceramics with as-fired densities ranging from 92-99.9%; Titanium, titanium alloys, and their associated oxides; Polymer Matrix Composites, for example carbon fiber-reinforced KAPTON and/or Metal Matrix Composites.

[0070] The substrate may include, for example, a "pre-stress" layer, such as a stainless material (300- or 400-series, for example SS301 provided by Brown Metals); an "electroactive" element, such as a PZT ceramic and/or a PZT ceramic with metallization layers present on one or more major surfaces.

[0071] As an example of a method of making a diacetylene-containing polyimide adhesive of the invention, a copolyimide (CPI) is made using 100 mole% 4,4'-(4,4'- isopropylidinediphenoxy)bis(phthalic anhydride)(UDA), with a separate diamine composition and monomer combination containing 70-98 mole% 4,4'-(1 ,3- phenylenediisopropylidine)bisaniline (PDPB), and 30-2mole% 1 ,4-Bis(3- aminophenyl)butadiyne (X-linker). The diamines are first dissolved in anhydrous N- methylpyrollidone (NMP), then the dianhydhde added and mixture are stirred mechanically for 24-72 hours under a dry nitrogen atmosphere. The resulting poly(amic acid) (PAA) solution is cast into a film and cured for ½ hour at each of 60°C, then 100°C, then 150°C, then 200°C with 5 minutes taken to ramp from lower to higher temperature to convert it to polyimide, resulting in a film.

[0072] The following further examples of diamine-dianhydride combinations useful in the present technology as described herein and summarized in Table 2 include the following:

[0073] A- 2 parts 3,4'-PDPB diamine, 2 parts 4,4'-BAPS diamine, 4 parts UDA - which produced a polyimide with a Tg of 198°C;

[0074] B- 1 part 3,4'-PDPB diamine, 3 parts 4,4'-BAPS diamine, 4 parts UDA - which produced a polyimide with a Tg of 207°C; and

[0075] C- 3 parts 3,4'-PDPB diamine, 1 part 4,4'-BAPS diamine, 4 parts UDA - which produced a polyimide with a Tg of 190°C.

[0076] D -4 parts 4,4'-BAPS, 4 parts UDA produced a polyimide with a Tg of 212°C. [0077] A further example of a copolyimide of an example embodiment contains the following constituents: 100 mol% UDA; 90 mol % 3,4'-PDPB, 10 mol % X-linker (3-(4- (3-aminophenyl)buta-1 ,3-diynyl)benzenamine)) and 4.4 wt% thacrylate (CAS Number 28961 -43-5).

[0078] A further example of a polyimide of an example embodiment contains the following constituents: 100 mol% UDA; 100 mol % 3,4'-PDPB and 34 wt% polymer

diepoxide ( , wherein n is such that the epoxide has a molecular weight of 1075).

[0079] The following is an example of a formulation which includes Diacrylates, such as poly(ethyleneglycol) diacrylate (Aldrich 437441 (2007), mol wt average Mn -575): 0.503g UDA/3,4'-PDPB with 33.5mg "diacrylate" in 2.61g NMP, resulting in 17wt% solids in solution; stirred for 16 hours; cast polygamic acid) on glass plate and cure as with the thermal stepping program described herein.

[0080] The following is an example of a formulation which includes an additive of the present technology: a copolyimide film was made by adding 0.504g of "tri-aziridine" to 5.038g of UP/3,4'-PDPB poly(amic acid) already dissolved as 15wt% in NMP, followed by magnetically stirring until homogenous, then cast solution onto glass plate and thermally imidize through thermal stepping program described herein.

[0081] The following is an example of a formulation of the present technology which includes PDMS as an additive: 0.241 g amine terminated PDMS was dripped onto a wax paper holding 1.7955g 3,4'-PDPB (344.5 g/mol); resulting solids were placed into solution containing 15.5ml NMP and 2ml_ THF; add 2.731 Og UDA (520.49 g/mol) and stirred for 16 hours to create poly(amic acid) solution; and cast solution onto glass plate and thermally imidize through thermal stepping program described herein.

[0082] The following is an example of a formulation useful in an example embodiment which includes poly(butanediol)as an additive: 3.2267g of 3,4'-PDPB (344.5 g/mol) and 0.5384g poly(butanediol) were dissolved in 2OmL NMP; add 5.467g UDA (520.49 g/mol) and rinsed in residues with 15ml_ NMP; stirred for 16 hours, resulting in polygamic acid) solution.

[0083] In use, the exemplified polyimide produced by using 4 parts UDA dianhydride, 3 parts 3,4'-PDPB diamine, and 1 part 4,4'-BAPS diamine was cast on a glass plate in polygamic acid) form as 20wt% solids in N-methylpyrollidinone. The PAA was thermally imidized to a peak temperature of 180°C, with the resulting polyimide film exhibiting 2.5% retained solvent (NMP) via thermogravimethc analysis.

[0084] A second selected polyimide produced by using 4 parts UDA dianhydride, 3 parts 3,4'-PDPB, and 1 part 4,4'-BAPS diamine was cast on a glass plate in poly(amic acid) form as 20wt% solids in N-methylpyrollidinone. The PAA was thermally imidized to a peak temperature of 200°C, with the resulting polyimide film exhibiting 0.0% retained solvent (NMP) via thermogravimetric analysis.

[0085] An example film prepared according to the foregoing general method and specifically comprised of 100 mole% UDA, 90 mole% PDPB and 10 mole% X-linker (i.e., Dianhydride (100 mole % UDA) and Diamine (90 mole% PDPB, 10 mole% X- linker) wherein total moles of dianhydride are equivalent to total moles of diamine has a glass transition temperature (T₉) of 181°C and gives off enthalpy of crosslinking beginning at 290°C (T_onSet) and with the maximum rate (T_maximum, temperature of peak exotherm) at 336°C and completing before 400°C. The fact that no exothermic transition is observed during a second heating to 400°C indicates that the crosslinking reaction is complete. When used as a hot melt adhesive, the film undergoes only a portion of the full possible extent of reaction resulting in a bond made with "lightly" crosslinked polyimide. The fact that the onset of crosslinking is observed at 290°C indicates that the film is composed of purely linear polyimide before lamination.

[0086] The cross linked film according to the technology therefore can be considered a latent cross linked film wherein the final heating of the film adhesive in a thermal compression method, in the manufacture of a piezoelectric device according to the invention, for example, forms cross links in the adhesive to increase pull strength and decrease the prevalence of creep (i.e., permanent deformation with the presence of temperature and applied stress) within a given polyimide film. [0087] The "latent" crosslinked product of the present technology will be substantially crosslinked at a temperature above that necessary to imidize the product when using a thermal imidization method. Substantially crosslinked includes lightly-to-heavily crosslinked system wherein 5%-100% of the linear system becomes entangled in a cross-linked network (as can be measured by Mass Spectrometry). Lightly crosslinked polymers have concentrations typically in the range of an average of one cross link for every 100 to 1500 monomer repeat units. In highly crosslinked systems, the upper concentration limit is at or above one crosslink per monomer unit. This system allows for the imidized polymer to act in the preferred adhesive manner by being able to act as an adhesive at an elevated temperature T1 and having the cross-link process engage at an elevated temperature T2 that is higher than T1. In this manner, a technological advantage results as the cross-linked system is strongly adhered to the desired substrates and also retains the desired mechanical properties and environmental resilience of the cross-linked network, which is created after adhesion is ensured.

[0088] The kinetics of a thermally crosslinked system typically follow an Arrhenius behavior, with extent of reaction increasing rapidly with increasing temperature. Therefore, as desired the user may control the extent of cross-linking by limiting the upper elevated temperature T2 or by controlling the dwell time at, above, or below the elevated temperature T2. For example, a given polymer system with a Tg of 185°C and with a cross-linker additive that initiates cross-linking at approximately 250°C can be bonded to a selected substrate and subsequently cross-linked by heating and compressing the polymer to the given substrate through a temperature cycle from 25°C to 280°C to 40°C in a 34s time period, with 10s of total time spent at or above the cross-linking activation temperature.

[0089] As another example film, a film of a homopolymer of UDA and a cross-linker (X-linker) such as are described herein shows similar thermal behavior to the copolymer of the first example film described above (i.e., a copolyimide (CPI) made using 100 mole% 4,4'-(4,4'-isopropylidinediphenoxy)bis(phthalic anhydhde)(UDA), with a separate diamine composition and monomer combination containing 70-98 mole% 4,4'-(1 ,3-phenylenediisopropylidine)bisaniline (PDPB), and 30-2mole% 1 ,4- Bis(3-aminophenyl)butadiyne (X-linker)). The main difference is that T_onSet (the lowest temperature at which a discernable exothermic reaction for cross-linking is present) is decreased to 242°C (from 290°C) and the maximum rate of crosslinking (temperature of peak exotherm) occurs at 300°C (as compared with 336°C). This polyimide formulation is preferred for the manufacture of a ruggedized laminated piezoelectric.

[0090] In general, the use of a cross-linker according to the present technology produces a lower T_onSet and T_ma_Xlmum- Preferred ranges for T_onSet are between 200°C and 300°C and for T_maximum between 220°C and 330°C. Preferred polyimides and copolyimides of the technology have a T_onSet higher than the peak film curing temperature (typically about 200°C) and lower than the peak actuator laminating temperature (typically about 280°C).

[0091] Thus, when incorporated into polyimide film, the diacetylene group provides a thermosetting property. The temperature range over which useful amounts of crosslinking reaction occurs is well aligned with a desired temperature profile used for lamination of a ruggedized laminated piezoelectric. An example of a temperature profile for lamination within a ruggedized laminated piezoelectric actuator using a low Tg film of the technology with a T_onSet of 242°C, for example, would be increasing from 25°C to 285°C in a 20s (20 seconds) time period and cooling from 285°C to 50°C in a 20s time period for a total thermal cycle time of 40s, with 10s spent above the Tonset temperature of 242°C. Due to the chemical reaction occurring at the same time as the lamination, the diacetylene-containing polyimide adhesive provide high temperature and long term bond stability.

[0092] In a preferred formulation of the present technology, a cross linker, as are described herein, is a diamine monomer present in an amount of about 2-30 mol %, such as 5 mol %, of total polyimide .

[0093] Preferably the polymer molecules are produced with diaminodialkyne or diacetylene groups within the linear polymer chain as opposed to on the end of the chain or as side chains. Furthermore, crosslinking is preferably employed at a very low level (i.e., an average of about one cross link site for every 100 to 1500 monomer repeat units as measured by Mass Spectrometry) to achieve the desired thermosetting property.

[0094] An example of a substrate partially and/or wholly coated according to the present technology includes, for example, a UDA/3,4'-PDPB polyimide with 10% cross-linker additive and 4.8% Triacrylate additive (UPLT™ film) bonded to a sputtered nickel alloy deposited on a base chromium alloy, with all metallization deposited on a PZT (piezoelectric) ceramic substrate provided by TRS Technologies Incorporated ("300 HD" formulation) provided a pull strength (ASTM D-4541 -02) of 20.2MPa, with failure cohesive within the polymer rather than adhesive of the polymer to the metallization. A second "pre-stress" layer, such as Beryllium Copper (for example, BeCu alloy 25 provided by Hamilton Precision Metals) could also be included. Any number of additional pre-stress layers or electroactive elements could also be included according to the present technology.

[0095] The polyimide and/or copolyimide of the technology may be used to prepare the following articles: a solvent cast film, an extrudable object, a fiber-reinforced composite, a neat resin molding, a coating, a hot-melt adhesive film, a hot-melt adhesive cloth, a hot-melt adhesive tape, a fiber, a filled resin molding and a matrix composite. The matrix composite further comprises a powder. As a preferred embodiment, this powder is selected from the group consisting of: plastic, metal, graphite and ceramic.

[0096] The following are example formulations for making polyimide (Pl) and/or copolyimide (CPI) that have low glass transition temperature (Tg):

[0097] Formulation 1

A diamine, 3,4'-(1 ,3-phenylenediisopropylidene)bisaniline (3,4'-PDPB) or 4,4'- (1 ,4-phenylenediisopropylidene)bisaniline (4,4'-PDPB) or 4,4'-diaminodiphenyl sulfide (4,4'-BAPS), and a dianhydride, 4,4'-(4,4'- isopropylidenediphenoxy)bis(phthalic anhydride) (UDA) are reacted to obtain a polyimide film (UP) with a lower glass transition temperature (Tg) than currently available and/or used classes of polyimide adhesives, such as LaRC-SI, good solubility, stable thermal and mechanical properties. For the structures of UDA; 3,4'-PDPB; 4,4'-PDPB; and 4,4'-BAPS, see Table 1 and Fig. 2, Fig. 5, Fig. 6, and Fig. 4, respectively.

[0098] Formulation 2

UDA is polymerized with two or more diamines to provide a copolyimide (CPI) film with a glass transition temperature (Tg) from 170 to 240°C. The exact structure of the diamines chosen can impart additional features to the polyimide

(Pl) film for producing stronger adhesion. These diamines can include aliphatic group - containing monomers (3,4'-PDPB, 4,4'-PDPB, sulfur - containing monomers (4,4'-diaminodiphenyl sulfide (4,4'-BAPS), 3,4'-diaminodiphenyl sulfide (4,4'-BAPS)), or bis(acetylene) containing monomers (referred as X- linker). The amine terminated poly(dimethyl siloxane) can also be used for this purpose. For the structures of UDA; 3,4'-PDPB; 4,4'-PDPB; 4,4'-BAPS; and X- linker, see Table 1 and Fig. 2, Fig. 5, Fig. 6, Fig. 4, and Fig. 7 Fig. 4, respectively.

[0099] Formulation 3

Blending different epoxide terminated polymer or acrylate terminated start polymer dopants in polygamic acid) solution, a reaction intermediate of polyimide (Pl), can also further lower glass transition temperature (Tg) of the blend to the range of 110 - 170°C.

[00100] Poly(amic) acids and/or Polyimide (Pl) and/or copolyimide (CPI)developed according to the present technology advantageously has lower glass transition temperature (Tg) and good solvent solubility in some common solvents, such as NMP, DMAc, toluene, tetrahydrofuren (THF) and some solubility in acetone. These properties are not commonly displayed by most other polyimides, which greatly improve the processability of such polymers. The polyimide (Pl)/copolyimide (CPI) can be used as the hot melt adhesive at lower bonding temperature.

[00101] Except for the free standing films, the polyimides (Pl)/copolyimides (CPI) described herein are suitable for the manufacture of shaped articles of very diverse types, such as fibers, coatings, foams, powders and the like with the use of customary additives, such as pigments, fillers etc.

[00102] Example 1 : Polvimide (Pl) Film

[00103] After 0.689 g of 3,4'-PDPB was dissolved in 1 -methyl-2-pyrrolidinone

(NMP) in a 100-mL three-neck round bottom flask equipped with a mechanical stirrer, a drying tube and a flow of dry nitrogen, 1.041 g of UDA was added slowly until the reagents were present in stoichimetric proportions at 15 wt-% solids. The mixture was stirred at room temperature overnight. Following by the removal of the formed poly(amic acid) solution from the reaction flask, it was doctored onto a clean, dry glass plate using a drawing blade. To effect the solvent removal and imidization, the polygamic acid) films were cured in a programmed conventional oven for half an hour at the ascending temperatures of 60°C, 100°C, 150°C and finally at 200°C with five minutes to heat from one temperature to the next highest. The obtained UP film is transparent, tough and flexible. The glass transition temperature (Tg) of such film is 186°C. Such UP film was used as hot melt adhesive for lamination of a ruggedized laminated piezoelectric element and displays consistently strong pull-off adhesion tensile strength with no adverse device performance effects (e.g., an average pull-off strength of 13.8MPa, as measured according to ASTM D4541 -02 (10-Feb-2002), when bonded to stainless and piezoelectric electrode substrates.

[00104] Example 2: Polvimide (Pl) Film

[00105] After 0.689 g of 4,4'-PDPB was dissolved in N,N-dimethylacetamide (DMAc), 1.041 g of UDA was added slowly in the reaction until the reagents were present in stoichimethc proportions at 15 wt-% solids. The mixture was stirred at room temperature overnight under a flow of dry nitrogen. Following the same film casting and curing procedures as shown in Polyimide (Pl) Film Example 1 , a transparent, tough and flexible film was obtained, having a glass transition temperature (Tg) of 219°C.

[00106] Example 3: Polvimide (Pl) Film

[00107] 1.041 g of UDA was slowly added in 0.433g of BAPS - NMP solution until the reagents were present in stoichimetric proportions at 15 wt-% solids, the mixture was stirred at room temperature overnight under a flow of dry nitrogen. Following the same film casting and curing procedures as shown in Polyimide (Pl) Film Example 1 , a transparent, tough and flexible film was obtained, having a glass transition temperature (Tg) of 215°C.

[00108] Example 4: Copolvimide (CPI) Film

[00109] After 0.699 g of 3,4'-PDPB was dissolved in DMAc, 1.041 g of UDA was added slowly in the reaction until the reagents were present in stoichimetric proportions at 15 wt-% solids. At the same time, another 4,4'-PDPB/UDA solution was prepared using the same formulation. Both mixtures were stirred at room temperature overnight under a flow of dry nitrogen. Then equal amount of each solution was mixed in another vessel for another 24 hours. Following the same film casting and curing procedures as shown in Example 1 , a transparent, tough and flexible film was obtained having a glass transition temperature (Tg) of 190°C. The mole ratio of UDA, 4,4'-PDPB and 3,4'-PDPB is 2:1 :1 in this example. All other ratios such as 4:1 :3 and 4:3:1 were done based on the same methodology and the films' glass transition temperature (Tg) were 182°C and 207°C.

[00110] Example 5: Copolvimide (CPI) Film

[00111] After 0.517 g of 3,4'-PDPB and 0.325 g of 4,4'-BAPS were dissolved in NMP, 1.562 g of UDA was added slowly in the reaction until the reagents were present in stoichimethc proportions at 15 wt-% solids. The mixture was stirred at room temperature overnight under a flow of dry nitrogen. Following the same film casting and curing procedures as shown in Example 1 , a transparent, tough and flexible film was obtained, having a glass transition temperature (Tg) of 198°C. The mole ratio of UDA, 3,4'-PDPB and 4,4'-BAPS is 2:1 :1 in this example. All other ratios such as 4:1 :3 and 4:3:1 were done based on the same methodology and the films' glass transition temperature (Tg) were 190°C and 206°C. One example film containing three parts of 3,4'-PDPB to one part of 4,4'-BAPS produced an average pull-off strength of 13.6MPa , as measured according to ASTM D4541 -02 (10-Feb- 2002 ), during solvent lamination.

[00112] Example 6: Copolvimide (CPI) Film

[00113] After 37.528 g of 3,4'-PDPB and 2.812 g of X-linker were dissolved in

NMP, 63 g of UDA-NMP solution was slowly added dropwise to the reaction through an addition funnel until the reagents were present in stoichimetric proportions at 20 wt-% solids. The mixture was stirred at room temperature overnight under a flow of dry nitrogen. Following the same film casting and curing procedures as shown in Example 1 , a transparent, tough and flexible film was obtained. The film softened at

148°C and started to crosslink at 230°C. The structure of X-linker is illustrated in Table 1 and Fig. 7.

[00114] Example 7: Copolvimide (CPI) Film

[00115] After 31.005 g of 3,4'-PDPB was dissolved in NMP, 46.845 g of UDA- NMP solution was slowly added dropwise to the reaction through an addition funnel until the reagents were present in stoichimetric proportions at 15 wt-% solids. The mixture was stirred at room temperature overnight under a flow of dry nitrogen. Then 6.117 g of poly(epoxide) (PE) was added in 119.94 g of the formed PAA solution and its concentration was 34 grams of epoxide per 100 grams of PAA. The mixture was stirred for at least four hours to dissolve the solid PE and the solution was homogeneous. Following the same film casting and curing procedures as shown in Example 1 , a transparent, tough and flexible film was obtained. In addition, it would swell but not dissolve in NMP and had a glass transition temperature (Tg) of 151 °C. An example resultant film displayed an average pull-off tensile strength of 13.1 Mpa during hot-melt lamination. The structure of poly(epoxide) (PE) is illustrated in Table 1 and Fig. 10.

[00116] Example 8: Copolvimide (CPI) Film

[00117] After 13.347 g of 3,4'-PDPB and 1.001 g of X-linker were dissolved in NMP, 22.410 g of UDA was added slowly in the reaction until the reagents were present in stoichimethc proportions at 21 wt-% solids. The mixture was stirred at room temperature overnight under a flow of dry nitrogen. Then 1.67 g of triacrylate solution was blended in for another an hour. Following the same film casting and curing procedures as shown in Example 1 , a transparent, tough and flexible film was obtained having a glass transition temperature (Tg) of 178°C. The structure of triacrylate is illustrated in Table 1 and Fig. 11.

[00118] Example 9: DSC Measurement Techniques

[00119] A TA Instruments modulated Differential Scanning Calorimeter (DSC) was used to take Tg measurements, the onset of crosslinking (T_onSet), and peak crosslinking temperature for the polymers mentioned within this report. The following method has been used to measure these parameters for polymeric materials listed in this disclosure, with data recorded and analyzed per common industry standards using TA software:

[00120] Modulate +/- 1.00°C every 60 seconds

[00121] Ramp 10.00°C/min to 250.00°C

[00122] Isothermal for 2.00 min [00123] Jump to 60.00°C

[00124] Isothermal for 10.00 min

[00125] Ramp 10.00°C/min to 340.00°C

[00126] Data storage: Off

[00127] Ramp 25.00°C/min to 20.00°C

[00128] End of method

[00129] A comparable method for measuring these parameters can also be found in the ASTM d3418-03 DEC 2003 and ASTM E1356-03 APRIL 2003.

[00130] A TA Instruments Thermogravimetric Analyzer (TGA) was used to take measurements of retained solvent within the "solidified" polymer material. The following method has been used to measure this parameter for polymeric materials listed in this disclosure, with data recorded and analyzed per common industry standards using TA software:

[00131] Abort next segment if %/min > 1.00

[00132] Ramp 20.00°C/min to 100.00°C

[00133] Isothermal for 30.00 min

[00134] Ramp 10.00°C/min to 600.00°C

[00135] Isothermal for 5.00 min

[00136] Abort next segment if %/min < 0.05

[00137] End of method [00138] Percent weight loss at 300°C is reported during this test, as any retained solvent (i.e., NMP) will have released from the sample by this temperature while none of the polymeric material will have experienced any substantive deterioration.

[00139] Example 10: Adhesion Study

[00140] Polymer used:

[00141] 25 micrometer thick film of UDA/3,4'-PDPB polyimide with 10% cross- linker additive and 4.8% Triacrylate additive (UPLT™). Substrate adhesion produced via "hot melt" of film, with process conditions reaching a peak temperature of 280°°C, a total thermal processing time of 120-180s, and an applied pressure of 10-20psi throughout said thermal processing time.

[00142] Substrates used:

[00143] BeCu, Alloy 190 (1.90% Be), 3 mils thick (0.003", 76 microns)

[00144] Stainless Steel, Type 301 , 4 mils thick (0.004", 102 microns)

[00145] Lap Shear Testing:

[00146] Lap shear samples were prepared by cutting the BeCu and SS substrates to 1 " wide by 4½ " long. Two strips of the same metal were overlapped by 14" and a 1" by 14" piece of polyimide adhesive film was inserted between the strips. The materials were fixtured in a specially designed jig which clamped them together under pressure by hand-tightening the two halves of the jig using socket-head screws. Four samples of each variation were prepared.

[00147] Lap shear testing was done on an lnstron machine according to ASTM D1002. In all cases, the substrate broke before the adhesive joint failed. The breaks were random, above and below the joint, and there were no jaw breaks

[00148] Although various embodiments have been shown and described in detail, the claims are not limited to any particular embodiment or example. None of the above description should be read as implying that any particular element, step, range, or function is essential such that it must be included in the claims scope. The scope of patented subject matter is defined only by the claims. The extent of legal protection is defined by the words recited in the allowed claims and their equivalents. It is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangement.

[00149] All documents cited and/or referred to herein are hereby incorporated herein by reference.

[00150] The above exemplifications of the technology are summarized in the following Table 2.

TABLE 1

Table 2

Claims

We Claim:

1. A poly(amic) acid precursor containing at least one dianhydride according to formula (1 )

, and a diamine, wherein Qi and Q2 may the same or different and Ji and J₂ may the same or different; Qi and Q2 are -O- or -S- or a straight or branched, substituted or unsubstituted, Ci-C₆alkyl containing -O- or -S-; Ji and J2 are substituted or unsubstituted C₅-Ci₄ aryl, C₅-Ci₄ cycloalkyl, C₅-Ci₄ cycloalkylaryl, C1-C10 straight or branched chain alkyl; A is Qi or Q₂; and r and s are independently 1 , 2, 3, 4 or 5.

2. The poly(amic) acid precursor of claim 1 wherein Qi and Q₂ are -O- and Ji

and J₂ are

^^ , and A is -S- or a straight or branched, unsubstituted, Ci-C₆ alkyl.

3. The poly(amic) acid precursor of claim 1 wherein Qi and Q₂ are -O-; Ji and

, and A is -S- or branched, unsubstituted, CrC₆ alkyl; and r and s

4. The poly(amic) acid precursor of claim 1 wherein the dianhydride of formula

5. A polyimide or copolyimide formed from the poly(amic) acid precursor of one of claims 1 -4.

6. A film formed from or comprising the polyimide or copolyimide of claim 5.

7. An adhesive formed from or comprising the polyimide or copolyimide of claim 5.

8. A substrate or article containing a surface which is at least partially coated with a poly(amic) acid of one of claims 1 -4.

9. A substrate or article containing a surface which is at least partially coated with a polyimide or copolyimide of claim 5.

10. A poly(amic) acid precursor containing at least one dianhydride and 3,4'- (1 ,3-phenylenediisopropylidene)bisaniline.

11. The poly(amic) acid precursor of one of claims 1 -4, further comprising 3,4'- (1 ,3-phenylenediisopropylidene)bisaniline.

12. A polyimide or copolyimide formed from the poly(amic) acid precursor of claim 10.

13. A polyimide or copolyimide formed from the poly(amic) acid precursor of claim 11.

14. A film formed from or comprising the polyimide or copolyimide of claim 12.

15. A film formed from or comprising the polyimide or copolyimide of claim 13.

16. An adhesive formed from or comprising the polyimide or copolyimide of claim 12.

17. An adhesive formed from or comprising the polyimide or copolyimide of claim 13.

18. A substrate or article containing a surface which is at least partially coated with a poly(amic) acid of claim 10.

19. A substrate or article containing a surface which is at least partially coated with a poly(amic) acid of claim 11.

20. A substrate or article containing a surface which is at least partially coated with a polyimide or copolyimide of claim 12.

21. A substrate or article containing a surface which is at least partially coated with a polyimide or copolyimide of claim 13.

22. A poly(amic) acid precursor comprising a dianhydride and a diamine of the following formula (2)

wherein each R, which may be the same or different, are CR'R"(CH₂)nNH2,,

or , wherein R' and R" are each individually H or d-C₆ straight or branched alkyl and n is an integer from 1-60, or

either or both R are

or m is an integer from 1 -75.

23. A poly(amic) acid precursor of claim 22 wherein the diamine is 1 ,4-Bis(3- aminophenyl)butadiyne or 3-(4-(3-aminophenyl)buta-1 ,3-diynyl)benzenamine).

24. A poly(amic) acid precursor of one of claims 1 -4 further comprising a diamine of the following formula (2)

R^= = :R (2),

wherein each R, which may be the same or different, are CR'R"(CH₂)nNH2,,

or , wherein R' and R" are each individually H or C1-C-6 straight or branched alkyl and n is an integer from 1-60, or either or both R are or

m is an

integer from 1 -75.

25. A pol(amic) acid precursor of claim 10 further comprising a diamine of the following formula (2)

wherein each R, which may be the same or different, are CR'R"(CH₂)_nNH_2,,

or , wherein R' and R" are each

individually H or Ci-Cβ straight or branched alkyl and n is an integer from 1-60, or

either or both R are or m is an

integer from 1 -75.

26. A poly(amic) acid precursor of claim 24 further comprising 3,4'-(1 ,3- phenylenediisopropylidene)bisaniline.

27. A polyimide or copolyimide formed from the poly(amic) acid precursor of claim 22.

28. A polyimide or copolyimide formed from the poly(amic) acid precursor of claim 23.

29. A polyimide or copolyimide formed from the poly(amic) acid precursor of claim 24.

30. A polyimide or copolyimide formed from the poly(amic) acid precursor of claim 25.

31. A polyimide or copolyimide formed from the poly(amic) acid precursor of claim 26.

32. A film formed from or comprising the polyimide or copolyimide of claim 27.

33. A film formed from or comprising the polyimide or copolyimide of claim 28.

34. A film formed from or comprising the polyimide or copolyimide of claim 29.

35. A film formed from or comprising the polyimide or copolyimide of claim 30.

36. A film formed from or comprising the polyimide or copolyimide of claim 31.

37. An adhesive formed from or comprising the polyimide or copolyimide of claim 27.

38. An adhesive formed from or comprising the polyimide or copolyimide of claim 28.

39. An adhesive formed from or comprising the polyimide or copolyimide of claim 29.

40. An adhesive formed from or comprising the polyimide or copolyimide of claim 30.

41. An adhesive formed from or comprising the polyimide or copolyimide of claim 31.

42. A substrate or article containing a surface which is at least partially coated with a poly(amic) acid of claim 22.

43. A substrate or article containing a surface which is at least partially coated with a poly(amic) acid of claim 23.

44. A substrate or article containing a surface which is at least partially coated with a poly(amic) acid of claim 24.

45. A substrate or article containing a surface which is at least partially coated with a poly(amic) acid of claim 25.

46. A substrate or article containing a surface which is at least partially coated with a poly(amic) acid of claim 26.

47. The article of claim 8 wherein the article is a piezoelectric device.

48. The article of claim 9 wherein the article is a piezoelectric device.

49. The article of claim 18 wherein the article is a piezoelectric device.

50. The article of claim 19 wherein the article is a piezoelectric device.