recent advances in the development of processable ...

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Annu. Rev. Mater. Sci. 1998.28:599-630. Downloaded from www.annualreviews.org by University of Sussex on 05/17/12. For personal use only.

Annu. Rev. Mater. Sci. 1998. 28:599–630

RECENT ADVANCES IN THE DEVELOPMENT OF PROCESSABLE HIGH-TEMPERATURE POLYMERS1 Michael A. Meador Polymers Branch, NASA Lewis Research Center, Cleveland, Ohio 44135; e-mail: [email protected] KEY WORDS:

polymers, polyimides, composites

ABSTRACT High-temperature polymers have found widespread use in aerospace and electronics applications. This review deals with recent developments in the chemistry of these materials that have led to improvements in processability and hightemperature stability.

INTRODUCTION High-temperature polymers, in particular polyimides, have found a broad range of applications from structural materials in fiber-reinforced composites to thin films for use in electronics packaging and in emerging technologies such as photonic devices. This review concentrates primarily on developments related to the use of high-temperature polymers in structural applications. However, many of the developments we discuss can be or have been applied to other uses. In structural applications, fiber-reinforced high-temperature polymer matrix composites can offer significant advantages over other materials because of their low density and high specific strength. These composites are quite attractive for use in aerospace systems, e.g. aircraft engines, airframe, missiles, and rockets, where weight is critical (1). A one kilogram (or pound) reduction in the weight of an aircraft engine can yield as much as a twenty kilogram (or 1 The

US Government has the right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper

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pound) overall weight savings for the entire aircraft on which it flies! This weight reduction has substantial benefits in terms of fuel savings, an increased passenger or cargo load, or increased speed and maneuverability (for military aircraft). The durability and reliability of materials used in aerospace components is a critical concern. Among the materials requirements for these applications are a high glass-transition temperature, Tg, (at least 25◦ C higher than the intended use temperature), good high-temperature stability in a variety of environments, and good mechanical properties over a wide range of temperatures. In general, the stability and Tg of most organic polymers limit their use, at best, to applications in which temperatures are no higher than 350 to 370◦ C. In addition, a major requirement for any high-temperature polymer, regardless of use, is processability. Chemical structures, e.g. aromatic rings, that are inherently stable and yield polymers with a high Tg, also tend to produce polymers that have poor solubility in most organic solvents, very high melting or softening points, and melt viscosities that are too high to allow their processing by resin-injection molding or resin-transfer molding. A classic example of this is poly( p-phenylene), 1, which has both a high Tg and good thermal stability (Figure 1). Yet, poly( p-phenylene), often characterized as “brick dust,” melts at extremely high temperatures (above 500◦ C) and is insoluble in common organic solvents (2). Considerable efforts over the years have focused on developing monomers and additives that yield high-temperature polymers that are soluble in common organic solvents and have low-melt viscosities (10,000 h) at temperatures up to 230◦ C and for shorter times at temperatures as high as 316◦ C. Because of its good high-temperature performance and processability, PMR-15 is widely used in composites and adhesives for a variety of aircraft engine applications (12). The 1989 world-wide market for PMR-15 was on the order of 18,000 Kg/year ($5–10 M annually) (1). Despite projections that this market would triple by the year 2000, the demand for PMR-15 has basically stagnated at the 1989 level, primarily for two reasons—concern over the mutagenicity of MDA (13) and the high cost of fabricating PMR-15 engine components due to processing limitations. Over the past decade or so, much research has dealt with the development of environmentally friendly versions of PMR-15 that do not contain MDA (14, 15). Other norbornyl end-capped resins have been developed over the years, mainly to provide materials with improved handling and/or better high-temperature performance than PMR-15. These include LaRC-160 (16), PMR-II (17), and AFR-700 (18). A reduction in the temperature required for cross-linking PMR resins through the use of a carbomethoxy-substituted norbornyl end-cap has also been demonstrated (19).

OTHER ADDITION-CURED POLYIMIDES While norbornyl end-caps have been used successfully in a number of polyimide systems, there are some drawbacks to their use. The thermal-oxidative stability of the norbornene ring is poor due to the large amount of saturated carbons present in this structure. For this reason, the norbornyl end-cap and the structures that result from its cross-linking often become the oxidative weak link in polyimides in which it is used. In addition, processing problems can be encountered with norbornyl end-capped polymers due to the potential

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for formation of cyclopentadiene during cross-linking (20). These deficiencies have prompted the search for new addition-curable end-caps for polyimides.


Acetylene-Terminated Systems The use of acetylenes as reactive end-caps in polyimides has been studied extensively. Most of the early research in this area was done by Landis and co-workers (21–23). Acetylene-terminated imides (ATI resins) such as Thermid 600, 14, (Figure 5) have high Tgs (370◦ C for Thermid 600) and good thermal-oxidative stability at temperatures as high as 316◦ C (24). Unfortunately, the acetylene group in these systems polymerizes at 195◦ C—too close to the imidization temperature to allow for complete removal of condensation by-products. This can be partly overcome through the use of a polyimide precursor, isoimide 15, prepared at room temperature via reaction of the appropriate monomers in the presence of dicylohexylcarbodiimide (25). Rearrangement of 15 to polyimide 14 occurs at elevated temperatures without the formation of volatile by-products. It is possible to increase the polymerization temperature of acetylene endcaps by more than 100◦ C through the introduction of a second phenyl ring on the acetylene terminus. Recent research has focused on the use of end-caps containing this phenylethynyl group (26–31), in particular 4-phenylethynylphthalic anhydride (PEPA), 16 (Table 1).

Figure 5 Acetylene-terminated systems: Thermid 600 14 and its isoimide 15.

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HIGH-TEMPERATURE POLYMERS

Table 1 A comparison of some phenylethynylphthalic anhydride-terminated polyimides

Polymer

Diamine(s)

X

MWtheoret.

Tg (◦ C)

Td (◦ C)a

Reference

PETI-5

85% 18 + 15% 19 7 2

nil C(CF3)2 C(CF3 )2

5000 10000 10000

249 362 308

505 — 587

32 30 30

Temperature at 5% weight loss, measured by TGA in air at 10◦ C/min.

a

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The properties of three PEPA-terminated polyimides are compared in Table 1. All appear to be quite stable in air, having 5% weight loss values (measured by TGA) in excess of 500◦ C. Glass transition temperatures for these polyimides can be as high as 362◦ C for the p-PDA/6-FDA system. It should be noted that, in general, the Tgs of phenylethynyl-terminated systems are about 30◦ C lower than the corresponding norbornyl end-capped polyimides. Hergenrother and co-workers (32) have developed higher Tg polyimides using other phenylethynyl end-caps, e.g. 21, as well as pendant phenylethynyl groups, 22 (Figure 6). Because the phenylethynyl end-cap polymerizes without the formation of volatile by-products, the processability of these resins (as films, adhesives, and in composites) is good (33). One of these polyimides, PETI-5, is currently under evaluation for use in airframe applications for the High Speed Civil Transport.

Strained Ring Systems Another cross-linking approach that has been employed is the incorporation of strained ring systems into the polyimide either as end-caps or in the polymer backbone. These moieties undergo a ring opening at high temperatures to yield

Figure 6 Other phenylethynyl-containing polyimides.

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a reactive intermediate, e.g. an o-quinodimethane or a biradical, which then polymerizes. Stille and co-workers demonstrated that biphenylenes, 23, could be used as reactive end-caps for polyimide oligomers (34, 35). When heated above 300◦ C, 23 undergoes a ring-opening reaction to produce a biradical, 24, that can couple, thus leading to cross-linking (Figure 7). The activation temperatures for ring opening can be lowered through the use of Ni(0) catalysts. Cured films of biphenylene-terminated polyimides such as 27a have modest Tgs (261◦ C). High degrees of polymerization could not be achieved with these polymers, even in the presence of the Ni(0) catalyst. In addition, graphite-reinforced composites prepared with this polyimide had high-void contents (36). The

Figure 7 Biphenylene end-capped polyimides.

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authors postulate that incomplete curing of the biphenylene group might be due to reversion of biradical 24 to biphenylene. In order to overcome this reversion, a series of biphenylene end-capped polyimides having an internal acetylene unit were prepared (37). Biradical 24 can be trapped with an acetylene to form a diphenylphenanthrene, 26 (Figure 7). Polyimide 27b prepared from a 40/60 mixture of bis(3-aminophenyl)acetylene/4,40 ODA (DP = 11) and cured at 350◦ C had a Tg of 347◦ C and good stability in air (5% weight loss at 520◦ C by TGA). Celion 6000 graphite-reinforced composites were also prepared with biphenylene end-capped polyimides containing internal acetylene groups (38). The vapor phase polymerization of [2.2] paracyclophane, 28, is a well-known process for the preparation of poly( p-xylylene) (39). Thermolysis of 28 at 350◦ C produces biradical 29 (Figure 8), which polymerizes to high molecular weight poly( p-xylylene).

Figure 8 Cyclophane end-capped poly(quinoline)s and polyimides.

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Marvel and co-workers used a [2.2]paracyclophane unit as an internal crosslinking site in polyethers, polysulfones, and polyketones (40, 41). [2.2]Paracyclophanes have also been incorporated into poly(benzimidazoles) as crosslinking sites (42). Stille (43, 44) demonstrated the use of a [2.2]paracyclophane end-cap for poly(quinoline)s, e.g. 30. This system had good melt flow and a cured Tg of 252◦ C (Figure 8). [2.2]Paracyclophane has also been used as an end-cap for a series of 6-FDA/pPDA polyimide oligomers, 31, of varying chain lengths (n = 2–10) (Figure 8) (45). Neat resin disks of 31 (cured at 370◦ C) had Tgs as high as 353◦ C and onsets of decomposition in air (measured by TGA) around 560◦ C. Graphite fiber (T650-42 and T-40R) reinforced composites prepared with cyclophane end-capped polyimide 31 had Tgs near 350◦ C and thermal-oxidative stability equivalent to that of composites prepared with the corresponding norbornyl end-capped polyimides, e.g. PMR-II-50 (46).

Diels-Alder Systems Diels-Alder cycloadditions have been used in thermosetting polyimides (47). The most common of these involve the reaction of a bismaleimide, BMI, with some type of stable bisdiene, such as a bis(o-allylphenoxy)phthalimide (48), bispyrone (49), bisfuran (50–52), or polyfuran (53). Two examples of these reactions are shown in Figure 9. Jones and co-workers (49) utilized the Diels-Alder cycloaddition between bis(furyl)imide 32 and BMI 33 to produce polyimide 34. The authors postulate that dehydration of 34 occurs between 204 and 288◦ C, thus leading to a more stable polyimide 35. HMS carbon fiber-reinforced composites made with 34, processed at 400◦ F, and post-cured at 600◦ F had good initial flexural strengths at room temperature (123.5 Ksi) and at 600◦ F (127.5 Ksi). These composites had modest thermal-oxidative stability; samples aged in air for 1000 h at 316◦ C had an 18% weight loss. Flexural strengths of these composites dropped from 172 to 66 Ksi after aging under these conditions. AB systems such as 36 have also been investigated (54). Triimide 36, when cured at 265◦ C for 20 h, experienced a 10% weight loss (by TGA) in air or nitrogen at 470◦ C and had a 58% char yield at 800◦ C in nitrogen. Ottenbrite and co-workers (55) have prepared a series poly(amide imide)s, 41, in Diels-Alder polymerizations using 1,4-[N,N0 -bis(butadienyl-2-methyl)2,3,5,6-tetramethylbenzenes], 39, as bisdienes (Table 2). Reaction conditions are quite mild (12 h at room temperature followed by 15–30 h at 100–130◦ C). Poly(amide imide)s 41 were soluble in a variety of organic solvents, had high intrinsic viscosities, Tgs above 200◦ C, and modest thermal-oxidative stabilities. Data on some representative systems are given in Table 2.

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Figure 9 Examples of Diels-Alder polyimide systems based upon the reaction of a furan and maleimide.

Anthracenes have also been used as dienes in Diels-Alder polymerizations (Figure 10). Stevens reported that N-(2-anthryl)maleimide, 42, undergoes selfpolymerization via a Diels-Alder reaction to afford polyimide 43 (56). The molecular weight of 43, estimated by end-group analysis using ultra-violet visible spectroscopy to determine the concentration of unreacted anthracene groups, was low—on the order of 14,000 or a DP of 50. Stevens offers two possible explanations for this. Steric hindrance about the 9,10 position of the

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Table 2 Diels-Alder polyimides from 1,4-[N,N0 -bis(butadienyl-2methyl)-2,3,5,6-tetramethylbenzenes and bismaleimides

41a 41b 41c 41d 41e

R

Ar

ηinh (dL/g)

Tg (◦ C)

CH3 Ph 4-NO2Ph Biphenyl Naphthyl

BMPM BMPM BMPM BMPM BMPM

0.55 0.81 0.52 0.63 0.64

219 215 260 218 222

10% TGA Weight Loss in Air (◦ C) 330 321 355 333 342

anthracene ring could inhibit cycloaddition, thereby limiting molecular weight. Chain scission by a competing retro-Diels-Alder reaction, typical for many Diels-Alder polymers, might also lead to less than optimal molecular weights. Polyimide 46 was prepared by the Diels-Alder reaction between an anthracene end-capped imide oligomer, 44, and 1,4,5,8-tetrahydro-1,4,5,8diepoxyanthracene, 45. Molecular weights for 46 are modest—on the order

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Figure 10 Two examples of Diels-Alder polyimides prepared using anthryl groups as the diene.

of 40,000 (57). Dehydration of 46 occurs in air at 310–355◦ C to give 47 (58), which cannot undergo degradation by the typical retro-Diels-Alder route. Reactive bisdiene intermediates have also been used in polyimide synthesis. Tolbert and co-workers (59) recently reported that bisdiene 49, generated by thermolysis of dihydrothiophenedioxide 48, could be trapped with a BMI to produce polyimide 51 (Figure 11). The onset of decomposition of 51 (measured by TGA) was in excess of 500◦ C. Benzocyclobutenes, 52, have been utilized as reactive diene precursors in Diels-Alder polymerizations (60, 61). The pioneering work with these systems was done by Tan & Arnold (62, 63). Thermolysis of 52 (at or above 200◦ C)

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Figure 11 Polyimides from dihydrothiophenedioxide 48.

yields o-quinodimethane 53, which can be trapped with dienophiles to afford the corresponding tetralin, 55 (Figure 12). The Tgs and thermal-oxidative stabilities of a series of polyimides prepared from 2,2-bis[4-(N-4-benzocyclobutenyl phthalimido)]hexafluoropropane, 56, and a commercial BMI mixture, Kerimid 353, are given in Table 3. Use of higher molar concentrations of Kerimid produced polyimides with low Tgs and poor thermal-oxidative stability, presumably due to the poor stability of bismaleimide 57a used in the Kerimid mixture. AB systems, containing both a benzocyclobutene and a maleimide end-cap, have also been prepared (59). In the absence of a dienophile, benzocyclobutenes will self-polymerize (64, 65). This reaction has been applied to the cross-linking of poly(amide)s with benzocyclobutenes either as pendant groups (66) or in-chain (67). o-Quinodimethanes such as 59 can also be generated photochemically from o-methylphenyl ketones, 58, and trapped with a variety of dienophiles

Figure 12 Formation of and Diels-Alder trapping of o-quinodimethane 53.

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Table 3 Polymides from benzocyclobutenes Molar Ratio BCB:Kerimid

Tg (◦ C)a

1:0 1:1 1:1.5 1:2 1:3

— 280 265 235 230

a

% Weight Loss, 200 h at 343◦ C 12 13 14 22 24

Measured by DSC.

(Figure 13) (68, 69). A route to polyimides has been demonstrated, wherein 2,5-dibenzoyl-p-xylene, 61, is used to generate two o-quinodimethanes that can be trapped with a BMI to give polyimides such as 63. Conversion of these polyimides into fully aromatized systems can be accomplished using standard organic chemistry.

BACKBONE MODIFICATIONS Other efforts to improve polyimide processability have dealt with modifications to the polyimide backbone to inhibit crystal packing. This is accomplished via a number of approaches ranging from the introduction of bulky pendant groups, e.g. phenyl or t-butyl, twisted or non-coplanar structures, bicyclics, or multiring systems.

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Figure 13 Polyimides from photochemically generated o-quinodimethanes.

Bulky Pendant Groups Bulky pendant groups have been used to increase free volume and asymmetry in order to improve polymer solubility and melt processability. Introduction of a single pendant methyl or t-butyl group onto poly(ether ketone) 64 led to enhanced solubility of these polymers in chloroform, with little or no effect on Tg or Td (70) (Table 4). However, introduction of a second t-butyl group resulted in a threefold decrease in solubility and 24◦ C increase in Tg, due to the more symmetric structure of this polymer. This same effect has been observed in di-t-butyl substituted polyimides (71). Polyimides 65, prepared from 2,5-bis(4-aminophenoxy)-1,4-di-ter-t-butylbenzene and a variety of dianhydrides, had high Tgs and good thermal-oxidative

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Table 4 Solubility and thermal behavior of a series of alkylsubstituted poly(ether ketone)s

R

R0

Solubility in CHCl3 (weight %)

Tg (◦ C)

Tdi (◦ C)a

Td10 (◦ C)b

H CH3 t-Bu t-Bu

H H H t-Bu

0.7 6.3 9.8 3.2

148 146 154 178

445 437 447 448

475 451 464 460

a

Onset of decomposition, measured by TGA in N2 at 10◦ C/min. Temperature at 10% weight loss, measured by TGA in N2 at 10◦ C/min.

b

stability (Table 5). With the exception of 65f, these polyimides were insoluble in organic solvents due to the increased molecular symmetry brought about by the introduction of two t-butyl groups. Enhanced polyimide solubility has been achieved through the use of pendant phenyl substituents (72–74). Harris & Hsu (72) reported that polyimides 66, prepared from 2,5-diphenylpyromellitic dianhydride, were soluble in NMP, m-cresol, and sym-tetrachlorethane (Figure 14). The authors had some difficulty detecting the Tgs of these polyimides using differential scanning calorimetry (DSC), but estimate them to be near 320◦ C. The thermal-oxidative stabilities of 66 appeared to be quite good; 5% weight losses determined by TGA (10◦ C/min heating rate) in air were between 500 and 585◦ C. Harris (73) has also prepared a series of polyimides, 67, from a tetraphenyl-p-terphenyl diamine (Table 6). These polyimides have high Tgs and good thermal-oxidative stability but have limited solubility in organic solvents. Spiliopoulous & Mikroyannidis (74) have also used this diamine in the synthesis of several high-temperature polymers, including polyimide 67b, which is soluble in a variety of organic solvents. The unusually low Tg reported for 67b relative to the other systems in Table 6 might be due to the fact that a different technique was used to measure the Tg of this polymer. Wang and co-workers have prepared soluble polyimides from diphenylprehnitic dianhydride (75, 76). Alternating co-polyimides 68 and 69 (Figure 15) were reported to have good solubility in DMF, DMAc, NMP, and m-cresol

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Table 5 Thermal behavior of a series of polyimides prepared from 1,4-bis(aminophenoxy)2,5-di-t-butylbenzene

65a 65b 65c 65d 65e 65f

Tg (◦ C)

Td (◦ C)a

298 293 242 288 263 277

496 510 502 498 479 508

a Temperature at 10% weight loss, by TGA in air at a heating rate of 20◦ C/min.

(77). As-processed powders of 68 and 69 had fairly low 5% TGA weight loss temperatures in air (356 and 403◦ C, respectively), suggesting incomplete imidization. Thermal treatment (300◦ C for 10 min) of these powders to complete their imidization increased the 5% weight loss temperatures to 424 and 416◦ C, respectively. The good solubility of 68 and 69 was attributed not only to the added free volume induced by the pendant phenyl substituents, but also to the kinked structure of the prehnitic dianhydride. Effects of kinked structures on polyimide solubility and processability are discussed further in the next section.

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Figure 14 Polyimides from 2,5-diphenylpyromellitic dianhydride.

Table 6 A comparison of thermal properties of polyimides from 4,400 -diamino-3,5,300 ,500 -teraphenyl-p-terphenyl

67a 67b 67c 67d

X

ηinh (dL/g)a

Tg (◦ C)b

Td (◦ C)c

nil CO O SO2

0.73 0.62 0.34 0.83

376 265 318 316

566 600 528 548

Reference 73 74 73 73

Intrinsic viscosity, measured in DMAc (67b) or DMF at 30◦ C. Measured by TMA in N2 at 20◦ C/min (67b) or at change in slope of DSC curve at heating rate of 20◦ C/min. c Onset of decomposition (67b) or temperature at 5% weight loss in TGA in air at 10◦ C/min. a

b

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Figure 15 Alternating co-polyimides from diphenylprehnitic dianhydride.

Twists, Kinks, and Crankshafts Monomers with twisted, kinked, or crankshaft-like structures have also been used to enhance polymer solubility and processability. Much attention has been focused on the use of twisted or non-coplanar monomers such as 2,20 -disubstituted and 2,20 ,6,60 -tetrasubstituted benzidines. Gaudiana and co-workers (78, 79) demonstrated that poly(amide)s prepared from 2,20 -bis(trifluoromethyl)benzidine had good solubility in DMAc, tetramethylurea, and NMP. Harris and co-workers have prepared soluble polyimides from benzidines having 2,20 -bistrifluoromethyl (80–82), 2,20 -dimethyl (83, 84), and 2,20 -diphenyl (85) substituents. Chuang (86) has synthesized polyimides from 2,20 ,6,60 -tetramethylbenzidine. A comparison of the properties of some of these polyimides, 70, is given in Table 7. All are soluble in organic solvents, have fairly high Tgs, and good thermal and thermal-oxidative stability. Intrinsic viscosities of 70e,g,h, and k, prepared from biphenyldianhydride, are extremely high, enabling the spinning of high-strength fibers. For example, fibers prepared from 70g have a tensile strength equivalent to that of Kevlar and nearly twice its compressive strength (87). Addition-cured polyimides have also been prepared from some of these benzidines and evaluated for use in composites (84, 88). 1,1-Binaphthyl-2,2-diyl and biphenyl-2,2-diyl units have been used to improve polymer solubility and processability (Figure 16). Soluble, high Tg poly(amide)s have been prepared from 2,20 -bis(4-aminophenyl)biphenyl, 71,

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Table 7 Some properties of polyimides containing 2,20 -di-substituted and 2,20 ,6,60 -tetrasubstituted biphenyl moieties

R

X

Y

[η]a

Soluble in m-cresol m-cresol, NMP, TCE m-cresol, NMP m-cresol, NMP, TCE m-cresol m-cresol, p-Cl phenol m-cresol m-cresol m-cresol, TCE, NMP m-cresol, TCE, NMP m-cresol, TCE, NMP

70a 70b

CO O

CF3 CF3

— —

1.6 1.1

70c

SO2

CF3

—

1.0

70d

C(CF3)2

CF3

—

1.9

70e 70f

nil O

CF3 CH3

— —

4.9 1.35

70g 70h 70i

nil nil O

CH3 Ph Ph

— — —

10 5.1 1.03

70j

O

CH3

CH3

1.4

70k

nil

CH3

CH3

5.0

Tg (◦ C)b

Td (◦ C)c

Reference

ND 275

550 570

81 81

320

540

81

320

530

81

312 298

600 503

81 84

302 ND 263

500 607 579

85 85 85

306

490 (N2)

86

ND

525 (N2)

86

Intrinsic viscosity measured in m-cresol at 30◦ C. Mid-point of slope on DSC thermogram, measured at a 20◦ C/min heating rate. c Temperature at which 5% weight loss occurred on a TGA thermogram in air at a 10◦ C/min heating rate. a

b

(89), 2,20 -bis(4-aminophenoxy)biphenyl, 72, and 2,20 -bis(4-aminophenoxy)1,1-binaphthyl, 73, (90). A comparison of the properties of polyimides 74 prepared from 72 and 73 is given in Table 8. Although the stabilities of comparable polyimides containing biphenyl and binaphthyl units are similar, Tgs for the binaphthyl systems are more than 50◦ C higher than corresponding biphenyl polyimides. The more rigid polyimides, 74a and c (X = nil), are soluble only in hot m-cresol, whereas 74b and d (X = SO2) are soluble in both NMP and m-cresol at room temperature.

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Figure 16 Biphenyl and binaphthyl based diamines.

Table 8 Polyimides containing binaphthyl-2,20 -diyl and biphenyl-2,20 -diyl units

74a 74b 74c 74d

Diamine

X

74 74 75 75

nil SO2 nil SO 2

ηinh (dL/g)a

Tg (◦ C)b

Td (◦ C)c

0.77 0.69 0.56 0.59

230 235 307 294

545 510 555 480

Measured in concentration H2SO4 at 30◦ C. Determined by DSC at 20◦ C/min heating rate. c Temperature at 10% weight loss, determined by TGA at 10◦ C/min heating rate. a

b

621

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Ding and co-workers (91) have recently reported the use of a chiral monomer, 2,20 -bis(3,4-carboxyphenoxy)-1,10 -binaphthalene dianhydride, 75, in the synthesis of a series of optically active polyimides, 76 (Figure 17). The authors envisioned that polyimides prepared from different optical isomers of 75 might have different crystal-packing behavior that would lead to differences in solubility and processability. However, the solubility of polyimides derived from pure optical isomers (R or S) of 75 or a 50/50 R/S mixture had similar solubility in methylene chloride, chloroform, THF, DMSO, NMP, and DMAc. In addition, all polyimides had a Tg of 274◦ C and a 5% TGA weight loss in N2 at 450◦ C. Solubility and processability can also be enhanced by the placement of kinked or bent structures within the polyimide backbone. Table 9 shows a comparison of the solubility and Tgs of poly(ether imide)s, 77, prepared from catechol, resorcinol, hydroquinone, and 2,3-dihydroxynaphthalene derived bis(ether anhydride)s (92–94). Introduction of a kinked structure, such as in 77a and d, results in a considerable improvement in solubility over the rigid hydroquinonebased system, 77c. Poly(ether imide) 77a had a 30◦ C lower Tg than 77c, and good thermal-oxidative stability (Td for 77a was 450◦ C). In a different approach, Choi and co-workers (95) have utilized a series of 1,1-bis(4-aminophenyl)cyclohexanes in the synthesis of polyimides, e.g. 78 (Figure 18), that are soluble in NMP, DMF, TCE, m-cresol, THF, and chloroform

Figure 17 Polyimides from chiral 2,20 -bis(3,4-dicarboxyphenoxy)-1,10 -binaphthalene dianhydride 75.

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and have Tgs as high as 370◦ C (78a). Other structures used to improve polyimide processability include spiro-compounds (96–98) and diphenylfluorene or cardosystems (99–101). Crankshaft-type structures, such as those shown in Figure 19, have also been used to enhance polyimide solubility. Polyamides 79 prepared from 1,6bis(amino-phenoxy) napthalene are soluble in DMAc, DMF, and NMP, have Tgs up to 287◦ C (79b), and good thermal-oxidative stability (102). 4,40 -Binaphthyl1,10 ,8,80 -tetracarboxylic dianhydride has been used to prepare polyimides 80 with good solubility (with the exception of 80b) in m-cresol and TCE (103). These polyimides had Tg values in excess of 400◦ C, and 5% TGA weight losses at 548◦ C (80e) or higher.

Cage and Bicycloalkane Structures Cage and bicyclic structures have been used to increase polyimide solubility. For example, inclusion of diamantane, 81a (104), or adamantane, 81b (105) units provided polyimides that were amorphous and soluble in a variety

Table 9 Effect of dianhydride structure on the solubility and Tg of a series of poly(ether imide)s Tg (◦ C) 76a 76b 76c 76d

209 209 237 235

Soluble in

Reference

Sa

92 92 94 92

Sa NMP, m-cresol NMP, m-cresol

a Soluble in m-cresol, NMP, DMF, chloroform, CH2Cl2.

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Figure 18 Polyimides from 1,1-bis(4-aminophenyl)-3,3,5-trimethylcyclohexane.

of organic solvents, e.g. chloroform, m-cresol, o-chlorophenol, and NMP (Figure 20). In general, correspondingly substituted diamantane and adamantane polyimides have similar thermal-oxidative stability. The Tgs of the diamantane systems are about 30◦ C higher than those of the adamantane polyimides due to the more linear structure of diamantane 81a. Polyimides 82 prepared from bicyclo(2.2.2)octane dianhydride have excellent solubility in NMP, DMF, DMAc, and DMSO (Figure 21). These systems have Tgs as high as 383◦ C (82a) and onsets of decomposition (measured by TGA in N2 at 10◦ C/min) ranging from 462 to 509◦ C (106).

Branched Systems Branched and star polymers have lower intrinsic viscosities and better solubility than linear systems of the same molecular weight (107, 108). This is particularly true for dendrimers, where the intrinsic viscosity tends to increase with increasing molecular weight, until it reaches a limiting value, whereupon it decreases. This is believed to be due to a change in molecular morphology from rod-like (low-molecular weight) to globular (high-molecular weight). Branching and starred structures have been incorporated in polyimides, primarily to increase Tg. However, Jensen (109) has recently shown that PETI-5 modified by the inclusion of small amounts of a trifunctional monomer, triaminopyrimidine,

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Figure 19 Examples of crankshaft structures in poly(amide)s and polyimides.

83, had a significantly lower melt viscosity (600 poise at 335◦ C versus 10,000 poise for PETI-5 at 371◦ C). The Tg of the modified system (Figure 22) is higher than PETI-5 (291 versus 263◦ C), and the mechanical properties of films prepared with this polyimide are better. An interesting approach to branched systems involves the use of a rotaxane as a means of mechanically cross-linking or branching a polymer such as polyurethane, 84, (Figure 23) (110). This self-threading approach to branching has also been employed with polyacrylates (111). While neither of these

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Figure 20 Polyimides containing diamantane 81a and adamantane 81b units.

Figure 21 Polyimides prepared from bicyclo (2.2.2)octane-2,3,5,6-tetracarboxylic-2,3:5,6dianhydride.

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Figure 22 PETI-5 polyimide modified with triaminopyrimidine 83.

Figure 23 Mechanical cross-linking or branching of a poly(urethane) through the use of rotaxane units.

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systems has the Tg and stability for use at high temperatures, it is likely that such an approach could be adapted for polyimides.


CONCLUSIONS High-temperature polymers have come a long way since the early efforts at DuPont. Over the years, significant improvements have been made in the processability, stability, and high-temperature performance of these materials. This review has attempted to highlight some of the major recent developments in this area and identify general themes that might be followed for future work. While this field cannot be described as young, it still has a bright future. Recent research in the development of molecular solids (112–114), dendrimers, branched systems (115), and other novel polymer architectures (116) opens up new possibilities in the design of processable, durable, environmentally friendly high-temperature polymers. Visit the Annual Reviews home page at http://www.AnnualReviews.org.

Literature Cited 1. Meador MA, Cavano PJ, Malarik DC. 1990. Structural composites: design and processing technologies. Proc. ASM/ESD Advanced Composite Conf. 6th Annu. Detroit, pp. 529–39. Materials Park, OH: ASM Int. 2. Staniland PA. 1997. In Macromolecular Design of Polymeric Materials, ed. K Hatada, T Kitayam, O Vogl, pp. 509–21. New York: Dekker 3. Sroog CE, Endry AL, Abramo SV, Berr CE, Edwards WM, Oliver KL. 1965. J. Polym. Sci. A3:1373–90 4. Sroog CE. 1991. Prog. Polym. Sci. 16: 561–694 5. Sroog CE. 1969. Encyclopedia of Polymer Science and Technology. ed, HF Mark, NG Gaylord, 11:247–72. New York, Wiley 6. Volksen W. 1994. In Advances in Polymer Science, High Performance Polymers, ed. PM Hergenrother, 117:111–64. New York. Springer-Verlag 7. Gibbs HH. 1979. J. Appl. Polym. Sci. Appl. Polym. Symp. 5:207–22 8. Serafini TT, Delvigs P, Lightsey GR. 1972. J. Appl. Polym. Sci. 16:905–15 9. Wong AC, Ritchey WM. 1981. Macromolecules 14:825–31 10. Meador MAB, Johnston JC, Cavano PJ.

1997. Macromolecules 30:515–19 11. Ahn MK, Stringfellow TC, Lei J, Bowles KJ, Meador M. 1993. MRS Symp. Series 305 (High Performance Polymers and Polymer Matrix Composites) pp. 217– 30 12. Meador MA. 1995. Proc. 40th Int. SAMPE Symp. 40:268–76 13. US Dep. Health Hum. Serv., Current Intelligence Bull. 47, Methylenedianiline, July 28, 1986. Washington, DC: USDHHS 14. Hoyle ND, Stewart NJ, Wilson D, Bashcant M, Merz H, et al. 1989. High Perform. Polym. 1:285–98 15. Delaney E, Riel F, Vuong T, Beale J, Hischbuehler K, Leone-Bay A. 1992. SAMPE J. 28:31–36 16. St. Clair TL, Jewell RA. 1976. Proc. Natl. SAMPE Tech. Conf. 8:82–93 17. Serafini TT, Vannucci RD, Alston WB. 1976. NASA Rep. TMX-71984 18. Serafini TT, Cheng PG, Ueda KK, Wright MF. 1990. Proc. Int. SAMPE Tech Conf. 22:94–107 19. Waters JF, Sukenik CN, Kennedy VO, Livneh M, Youngs WJ, et al. 1992. Macromolecules 25:3868 20. Hay JN, Boyle JD, Parker SF, Wilson D. 1989. Polymer 30:1032–40

P1: ARS/dat

May 22, 1998

P2: ARS/ary

10:5

QC: ARS

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AR059-21


HIGH-TEMPERATURE POLYMERS 21. Bilow N, Landis AL, Miller RJ. 1974. U.S. Patent No. 3,845,018 22. Landis AL, Bilow N, Boschan RH, Lawrence RE, Aponyi T. 1974. Polym. Prepr. 15:537–41 23. Bilow N, Keller LB, Landis AL, Boschan RH, Castillo A. 1978. Proc. 23rd Nat. SAMPE Symp. 23:791–805 24. Hergenrother PM, Johnston N. 1979. Org. Coat. Plast. Chem. Prepr. 40:460–68 25. Landis AL, Naselow AB. 1982. Proc. Natl. SAMPE Tech. Conf. 14:236 26. Paul CW, Schultz RA, Fenelli St P. 1993. In Advances in Polyimide Science and Technology, Proc. 4th Int. Conf. Polyimides, ed. C Feger, MM Khojastech, MS Htoo, pp. 220–24. Lancaster, PA: Technomic 27. Paul CW, Schultz RA, Eenelli SP. 1992. U.S. Patent No. 5,138,028 28. Smith JG, Hergenrother PM. 1994. Polym. Prepr. 35:353–54 29. Harris FW, Pamidimukkala A, Gupta R, Das S, Wu T, Mock G. 1984. J. Macromol. Sci. A21:1117–35 30. Meyer GW, Glass TE, Grubbs HJ, McGrath JE. 1995. J. Polym. Sci. Polym. Chem. Ed. 33:2141–49 31. Smith JG Jr, Hergenrother PM. 1994. Polymer 35:4857–64 32. Smith JG Jr, Connell JW, Hergenrother PM. 1997. Polymer 38:4657–65 33. Hou TH, Jensen BJ, Hergenrother PM. 1996. J. Compos. Mater. 30:109–22 34. Vancraeynest V, Stille JK. 1980. Macromolecules 13:1361–67 35. Droske JP, Gaik UM, Stille JK. 1984. Macromolecules 17:10–14 36. Droske JP, Stille JK, Alston WB. 1984. Macromolecules 17:14–18 37. Takeichi T, Stille JK. 1986. Macromolecules 19:2103–8 38. Stoessel S, Takeichi T, Stille JK, Alston WB. 1988. J. Appl. Poly. Sci. 36:1847– 64 39. Gorham WF. 1966. J. Polym. Sci. Pt. A-1 4:3027–39 40. Sivaramakrishnan KP, Samyn C, Westerman IJ, Wong DT-M, Marvel CS. 1975. J. Polym. Sci. Polym. Chem. Ed. 13:1083–94 41. Chang DM, Marvel CS. 1975. J. Polym. Sci. Polym. Chem. Ed. 13:2507–15 42. Meyers RA, Hamersma JW, Green HE. 1972. Polym. Lett. 10:685–89 43. Upshaw TA, Stille JK. 1988. Macromolecules 21:2010–14 44. Upshaw TA, Stille JK, Droske JP. 1991. Macromolecules 24:2143–50 45. Waters JF, Sutter JK, Meador MAB, Baldwin LJ, Meador MA. 1991. J. Polym. Sci. Polym. Chem. Ed. 29:1917–24

629

46. Sutter JK, Waters JF, Scheurman MA. 1992. Polym. Prepr. 33:366–67 47. Stenzenberger HD. 1991. In Polyimides and Other High-Temperature Polymers, ed. MJM Abadie, B Sillion, pp. 215–32. Amsterdam: Elsevier 48. Stenzenberger HD, Koeing P, Romer W, Herzog M. 1991. Proc. Int. SAMPE Symp. 36:1232–43 49. Alhakimi G, Klemm E. 1995. J. Polym. Sci. Polym. Chem. Ed. 33:767–70 50. Jones RJ, O’Rell MK, Sheppard CH, Vaughan RW. 1977. SAMPE Q. pp. 18– 25 51. Berlin AA, Liogon’kii BI, Zapadinskii BI, Kazantzeva EA, Stankevich AO. 1977. J. Macromol. Sci. Chem. A11:1–28 52. Kuramoto K, Hayashi K, Nagai K. 1994. J. Polym. Sci. Polym. Chem. Ed. 32:2501– 4 53. Patel HS, Patel HD. 1992. High Perform. Polym. 4:19–33 54. Diakoumakos CD, Mikroyannidis JA. 1992. J. Poly. Sci. Part A: Poly. Chem. 30:2559–67 55. Smith JG Jr, Sun F, Ottenbrite RM. 1996. Macromolecules 29:1123–30 56. Stevens MP. 1984. J. Poly. Sci. Poly. Lett. Ed. 22:467–71 57. Meador MAB. 1988. J. Polym. Sci. Polym. Chem. Ed. 26:2907–16 58. Meador MAB, Meador MA, Ahn M-K, Olshavsky MA. 1989. Macromolecules 22:4385–87 59. He Z, Tolbert L. 1992. Polym Prepr. 33: 1000–1 60. Kirchhoff RA, Carriere CJ, Bruza KJ, Rondan NG, Sammler RL. 1991. J. Macromol. Sci. Chem. A28:1079–131 61. Kirchhoff RA, Bruza KJ. 1994. Advances in Polymer Science, High Performance Polymers, ed. PM Hergenrother, 117: 1–66. New York: Springer-Verlag 62. Ten LS, Arnold FE. 1988. J. Polym. Sci. Polym. Chem. Ed. 26:1819–34 63. Ten LS, Soloski EJ, Arnold FE. 1988. Cross-Linked Polymers ACS Symp. Ser. 367, pp. 349–65. Washington DC: Am. Chem. Soc. 64. Marks MJ, Sekinger JK. 1994. Macromolecules 27:4106–14 65. Marks MJ, Erskine JS, McCrery DA. 1994. Macromolecules 27:4114–26 66. Tan LS, Venkatasubramanian N. 1996. J. Polym. Sci., Polym. Chem. Ed. 34:3539– 49 67. Jiang T, Rigney J, Jones M-CG, Markoski LJ, Spilman GE, et al. 1995. Macromolecules 28:3301–12 68. Yang NC, Rivas CJ. 1961. J. Am. Chem. Soc. 83:2213

P1: ARS/dat

P2: ARS/ary

May 22, 1998

10:5


630

QC: ARS

Annual Reviews

AR059-21

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69. Sammes PG. 1976. Tetrahedron. 32:405– 22 70. Taguchi Y, Uyama H, Kobayashi S. 1996. J. Polym. Sci. Polym. Chem. Ed. 34:561– 65 71. Liaw D-J, Liaw B-Y. 1997. J. Poly. Sci. Part A, Polym. Chem. 35:1527–34 72. Harris FW, Hsu SL-C. 1989. High Perform. Polym. 1:3–14 73. Harris FW, Sakaguchi Y. 1989. Polym. Mater. Sci. Eng. Proc. 60:187–91 74. Spiliopoulos IK, Mikroyannidis JA. 1996. Macromolecules 29:5313–19 75. Wang ZY, Qi T. 1994. Macromolecules 27:625–28 76. Wang ZY, Qi Y. 1995. Macromolecules 28:4207 77. Wang ZY, Qi Y. 1996. Macromolecules 29:792–94 78. Roger HG, Gaudiana RA, Hollised WC, Kalyanaraman PS, Manello JS, et al. 1985. Macromolecules 18:1058–68 79. Gaudiana RA, Minns RA, Sinta R, Weeks N, Rogers HG. 1989. Prog. Polym. Sci. 14:47–89 80. Harris FW, Hsu SL-C, Tso CC. 1990. Polym. Prepr. 31:342–43 81. Cheng SZD, Wu Z, Eashoo M, Hsu SL-C, Harris FW. 1991. Polymer 32:1803–10 82. Eashoo M, Sen D, Wu Z, Lee CL, Harris FW, Cheng SZD. 1993. Polymer 34:3209–15 83. Kim YH, Moon BS, Harris FW, Cheng SZD. 1996. J. Therm. Anal. 26:921–33 84. Eashoo M, Wu Z, Zhang A, Shen S, Tse C, et al. 1994. Macromol. Chem. 195:2207– 25 85. Harris FW, Sakaguchi Y, Shibata M, Cheng SZD. 1997. High Perform. Polym. 9:251–61 86. Chuang KC. 1995. High Perform. Polym. 7:81–92 87. Li W, Wu Z, Jiang H, Eashoo M, Harris FW, Cheng SZD. 1996. J. Mater. Sci. 31:4423–31 88. Chuang KC, Vannucci RD, Ansari I, Cerny LL, Scheiman DA. 1994. J. Polym. Sci. Polym. Chem. Ed. 32:1341–50 89. Imai Y. 1996. Reactive Funct. Polym. 30:3–15 90. Liou G-S, Murayama M, Kakimoto M-A, Imai Y. 1993. J. Polym. Sci. Polym. Chem. Ed. 31:2499–506 91. Mi Q, Gao L, Ding M. 1996. Macromolecules 29:5758–59

92. Eastmond GC, Paprotny J. 1995. Macromolecules 28:2140–46 93. Eastmond GC, Paprotny J, Irwin RS. 1996. Macromolecules 29:1382–88 94. Takekoshi T, Kochanowski JE, Manello JS, Webber MJ. 1985. J. Polym. Sci. Polym. Chem. Ed. 23:1759–69 95. Yi MH, Huang W, Jin MY, Choi K-Y. 1997. Macromolecules 30:5606–11 96. Cella JA, Faler GR. 1989. U.S. Patent No. 4,864,034 97. Chao HS-I, Barren E. 1993. J. Polym. Sci. Polym. Chem. Ed. 31:1675–85 98. Hsiao S-H, Yang C-Y. 1997. J. Polym. Sci. Polym. Chem. Ed. 35:2801–9 99. Sillion B, Rabilloud G, Garapon J, Gain O, Vallet J. 1995. Mater. Res. Soc. Symp. Proc. 381:93–104 100. Yang C-P, Lin J-H. 1995. J. Polym. Sci. Polym. Chem. Ed. 33:2425–33 101. Moy TM, Konas M, McGrath JE, Fields EK. 1994. J. Polym. Sci. Polym. Chem. Ed. 32:2377–85 102. Yang C-P, Hisao S-H, Jang C-C. 1995. J. Polym. Sci. Polym. Chem. Ed. 33:1095– 105 103. Gao JP, Wang ZY. 1995. J. Polym. Sci. Polym. Chem. Ed. 33:1627–35 104. Chern Y-T, Shiue H-C. 1997. Macromolecules 30:5766–72 105. Chern Y-T, Shiue H-C. 1997. Macromolecules 30:4646–51 106. Matsumoto T, Kurosaki T. 1997. Macromolecules 30:993–1000 107. Frechet JMJ. 1994. Science 263:1710–15 108. Frechet JMJ, Hawker CJ, Wooley KL. 1994. J. Macromol. Sci. Pure Appl. Chem. A31:1627–45 109. Jensen BJ. 1996. Polym. Prepr. 37:222– 23 110. Gong C, Gibson HW. 1997. J. Am. Chem. Soc. 119:8585–91 111. Gong C, Gibson HW. 1997. J. Am. Chem. Soc. 119:5862–66 112. Stupp SI, Son S, Li LS, Lin HC, Keser M. 1995. J. Am. Chem. Soc. 117:5212–27 113. Stupp SI, LeBonheur V, Walker K, Li LS, Huggins KE, et al. 1997. Science 276:384–89 114. Philp D, Stoddart JF. 1991. SynLett. 7: 445–58 115. Dvornic PR, Tomalia DA. 1996. Curr. Opin. Coll. Interface Sci. 1:221–35 116. Kaszynski P, Friedeli AC, Michl J. 1992. J. Am. Chem. Soc. 114:601–20

Annual Review of Materials Science Volume 28, 1998


CONTENTS Jahn-Teller Phenomena in Solids, J. B. Goodenough Isotropic Negative Thermal Expansion, Arthur W. Sleight Spin-Dependent Transport and Low-Field Magnetoresistance in Doped Manganites, J. Z. Sun, A. Gupta High Dielectric Constant Thin Films for Dynamic Random Access Memories (DRAM), J. F. Scott Imaging and Control of Domain Structures in Ferroelectric Thin Films via Scanning Force Microscopy, Alexei Gruverman, Orlando Auciello, Hiroshi Tokumoto InGaN-Based Laser Diodes, Shuji Nakamura Soft Lithography, Younan Xia, George M. Whitesides Transient Diffusion of Beryllium and Silicon in Gallium Arsenide, Yaser M. Haddara, John C. Bravman Semiconductor Wafer Bonding, U. Gösele, Q.-Y. Tong Cathodic Arc Deposition of Films, Ian G. Brown The Material Bone: Structure--Mechanical Function Relations, S. Weiner, H. D. Wagner Science and Technology of High-Temperature Superconducting Films, D. P. Norton IN SITU STUDIES OF THE PROPERTIES OF MATERIALS UNDER HIGH-PRESSURE AND TEMPERATURE CONDITIONS USING MULTI-ANVIL APPARATUS AND SYNCHROTRON X-RAYS, J. B. Parise, D. J. Weidner, J. Chen, R. C. Liebermann, G. Chen STUDIES OF MULTICOMPONENT OXIDE FILMS AND LAYERED HETEROSTRUCTURE GROWTH PROCESSES VIA IN SITU, TIMEOF-FLIGHT ION SCATTERING AND DIRECT RECOIL SPECTROSCOPY, Orlando Auciello, Alan R. Krauss, Jaemo Im, J. Albert Schultz Perovskite Thin Films for High-Frequency Capacitor Applications, D. Dimos, C. H. Mueller RECENT DEVELOPMENTS IN CONDUCTOR PROCESSING OF HIGH IRREVERSIBILITY FIELD SUPERCONDUCTORS, J. L. MacManus-Driscoll Point Defect Chemistry of Metal Oxide Heterostructures, Sanjeev Aggarwal, R. Ramesh Processing Technologies for Ferroelectric Thin Films and Heterostructures, Orlando Auciello, Chris M. Foster, Rammamoorthy Ramesh The Role of Metastable States in Polymer Phase Transitions: Concepts, Principles, and Experimental Observations, Stephen Z. D. Cheng, Andrew Keller Processing and Characterization of Piezoelectric Materials and Integration into Microelectromechanical Systems, Dennis L. Polla, Lorraine F. Francis Recent Advances in the Development of Processable High-Temperature Polymers, Michael A. Meador High-Pressure Synthesis, Characterization, and Tuning of Solid State Materials, J. V. Badding

1 29 45 79 101 125 153 185 215 243 271 299

349

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397 421 463 501

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