Benzoxazole Imide Research Articles

Structural Regulation of Poly(benzoxazole imide)s and Their Composites with Fluorinated Graphene to Construct High-Performance Low Dielectric Films

Structural Regulation of Poly(benzoxazole imide)s and Their Composites with Fluorinated Graphene to Construct High-Performance Low Dielectric Films

Synthesis and properties of poly(benzoxazole imide)s derived from two isomeric diamines containing a benzoxazole moiety

The isomeric effect on the properties of novel series of poly(benzoxazole imide)s PI-a and PI-b derived from two isomeric diamines 2a and 2b is investigated.

Processable poly(benzoxazole imide)s derived from asymmetric benzoxazole diamines containing 4-phenoxy aniline: synthesis, properties and the isomeric effect

A novel series of poly(benzoxazole imide)s are synthesized using asymmetric benzoxazole monomers in an attempt to enhance solution and melt processability.

Superheat-resistant polymers with low coefficients of thermal expansion

Here, we report superheat-resistant polymers, poly(benzoxazole imide)s (PBOI), with very low coefficients of thermal expansion (CTE) and sufficient ductility for applications as the plastic substrates of organic light-emitting diode (OLED) displays. Diamines incorporating benzoxazole (BO) units were synthesized for this purpose. A PBOI derived from a BO-containing diamine and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) has excellent properties that are superior to those of s-BPDA/p-phenylenediamine (p-PDA) polyimide such as an undetectable Tg, a very low CTE (9.6 ppm K−1), a very high the 5% weight loss temperature (Td5 = 592 °C) in N2, and good ductility while remaining the highest level of non-flammability (UL-94, V-0). The use of another BO-incorporating diamine permitted further improvement in the target properties: an extremely high Td5 (609 °C) in N2 and a considerably low CTE (3.3 ppm K−1) close to that of a silicon wafer. These results show that the PBOIs examined in this work are promising candidates for use as the plastic substrates in OLED displays.

High-temperature polymers overcoming the trade-off between excellent thermoplasticity and low thermal expansion properties

Abstract An index describing the sharpness of glass transitions is proposed in this work. This index is closely connected to thermoplasticity, which was determined as the slope of logarithmic storage modulus (log E′)–temperature curves, that is, −d log E′/dT at a point just above the Tg determined by dynamic mechanical analysis (DMA). The main purpose of this work was to obtain high-temperature polymeric materials while simultaneously achieving low coefficients of thermal expansion (CTE 0.3) as an empirical benchmark without rubbery plateau (RP) regions in the DMA curves. However, it was very difficult to accomplish this goal because of the presence of a clear trade-off between lower CTE and higher thermoplasticity as observed in common polymer systems. Therefore, we designed a series of diamines incorporating benzoxazole (BO) units to develop novel poly(benzoxazole imide)s (PBOIs) with the expectation of weakening the intermolecular forces present in the systems by decreasing the amount of imide C=O groups. The combination of an ether-linked BO-incorporating diamine and a rigid tetracarboxylic dianhydride led to a PBOI with somewhat improved thermoplasticity and a significantly decreased CTE, however, it was difficult to completely remove the RP regions. On the other hand, a meta-phenylene-linked BO-incorporating diamine was effective in erasing the RP regions with a considerably high index (−d log E′/dT = 0.60) while keeping a relatively low CTE. This system was modified by copolymerization with a minor fraction of a p-linked BO-incorporating diamine. The resultant copolymer attained a low CTE (16.7 ppm K−1) close to that of copper foils and a high index (−d log E′/dT = 0.37) without RP regions. A reasonably high adhesion strength was also observed for the hot-compressed laminates between the copolymer film and copper foils. The copolymer prepared possessed a very high Tg of 362 °C, sufficient ductility, a relatively low water uptake of 1.57%, and the highest rank of non-flammability. Thus, the PBOIs developed in this work offer useful materials for potential applications as adhesive-free flexible printed circuits.

Effect of multiple H-bonding on the properties of polyimides containing the rigid rod groups

To investigate the influence of hydrogen bonding on the properties of polyimides (PIs) containing rigid rod-like groups, five symmetrical diamines containing benzimidazole, benzoxazole, and hydroxy group were synthesized, and then a series of PIs were prepared. Results showed that hydroxyl-containing poly(benzoxazole imide)s possess higher glass transition temperature (Tg) and dimensional stabilities than their corresponding poly(benzoxazole imide)s. Moreover, the corresponding poly(benzimidazole imide)s presented the best performances, such as the highest Tg, the highest char yield and the highest dimensional stabilities. The influence of hydrogen bonding of benzimidazole on the properties of PIs was stronger than that of hydroxyl groups. Hydroxyl-containing poly(benzoxazole imide)s were formed in crosslinking structures after heat treatment at 400 °C. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 570–581

Synthesis and properties of fluorescence poly(benzoxazole–imide)s containing naphthalene

Novel aromatic poly(benzoxazole–imide)s containing naphthalene were prepared from synthesized 1,4-di(5-aminobenzoxazol-2-yl)naphthalene and commercial dianhydrides by conventional two-step polymerization. The polymers showed high levels of tensile strength of up to 294 MPa and modulus of up to 6.5 GPa. The glass transition temperatures of the polymers were observed between 267°C and 345°C. The 5% weight loss temperatures of the polymers were tested in the range of 517–562°C in nitrogen atmosphere. The excellent properties of polymers were attributed to their rigid-rod-like molecular structure. The polymers emitted different fluorescence with maximum emission wavelengths in the range of 470–560 nm. Increasing the dianhydride electron affinity, the emission spectra peak value of polyimides (PIs) except PI6 increased gradually, but the fluorescent intensity of the PIs decreased. The 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride-derived PI film exhibit highly fluorescent characteristics; however, the PI film from pyromellitic dianhydride was nonfluorescent.

주사슬에 Trifluoromethyl 그룹을 갖는 Poly(benzoxazole imide)의 제조 및 난연 특성

2,2-Bis(3-amino-4-hydroxyphenyl)hexafluoropropane 와 방향족 디이미드-디카르복실산을 thionyl chloride, triethyl amine 및 NMP 하에서 직접 중축합하여 trifluoromethyl group을 포함하는 일련의 poly(hydroxyamide)s(PHAs)를 제조 하였다. PHAs은 <TEX>$35^{\circ}C$</TEX> DMAc 용액에서 0.54-0.96 dL/g의 고유점도를 보였다. 모든 PHAs은 여러 종류의 유기용매에 쉽게 용해되었으나, PBOs은 황산에 부분적으로 용해되는 것을 제외하고, 전혀 용해되지 않았다. PHAs은 열적고리화 반응에 의해서 흡열과 함께 PBOs로 전환되었다. PHAs의 최대 중량손실온도는 <TEX>$559-567^{\circ}C$</TEX>의 영역을 보였고, poly(benzoxazole imide)s(PBOs)은 47-59%의 비교적 높은 char 수득율을 보였다. PBOs의 Pyrolysis Combustion Flow Calorimeter(PCFC) 결과에서 12-19 W/g의 HRR 과 2.7-3.6 kJ/g의 total HR을 보였다. PBO 1의 HRR은 PBO 3 의 HRR (19 W/g)보다 37 % 낮은 12 W/g의 가장 낮은 값을 보였다. A series of poly(hydroxyamide)s (PHAs) having trifluoromethyl group were prepared by direct polycondensation of aromatic diimide-dicarboxylic acids with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane by thionyl chloride and triethyl amine in N-methyl-2-pyrrolidinone (NMP). The PHAs exhibited inherent viscosity in the range of 0.54-0.96 dL/g at <TEX>$35^{\circ}C$</TEX> in DMAc solution. All PHAs were readily soluble in a variety of organic solvents, whereas the polybenzoxazoles (PBOs) were quite insoluble except partially soluble in sulfuric acid. PHAs were converted to PBOs by thermal cycling reaction with heat of endotherm. The maximum weight loss temperature of the PHAs occurred in the range of <TEX>$559-567^{\circ}C$</TEX>. The PBOs showed relatively high char yields in the range of 47-59%. Pyrolysis Combustion Flow Calorimeter (PCFC) results of the PBOs showed 12-19 W/g heat release rate (HRR), and 2.7-3.6 kJ/g total heat release (total HR). The HRR of PBO 1 showed the lowest value of 12 W/g, which was 37% lower than that of PBO 3 (19 W/g).

The evolution of poly(hydroxyamide amic acid) to poly(benzoxazole) via stepwise thermal cyclization: Structural changes and gas transport properties

The thermally induced structure transformation and polymer chain rearrangement of a thermally rearranged (TR) material for gas separation has been explored in this work. A tremendous enhancement as high as 215 folds in CO2 permeability has been achieved by converting the pristine poly(hydroxyamide amic acid) (PHAA) to the final polybenzoxazole (PBO) via thermal cyclization at 400 °C for 2 h. The evolution of the pristine polymer PHAA derived from 2,2-bis(3-amino-4-hydroxyphenyl)hexafluropropane (BisAPAF) and trimellitic anhydride chloride (TAC) by thermal treatment from 130 °C to 400 °C has been examined by various characterization techniques including elemental analysis, TGA, TGA-IR, DSC, ATR-FTIR, XPS, XRD and Positron Annihilation Lifetime Spectroscopy (PALS). The stepwise cyclization process commences with cyclodehydration followed by cyclodecarboxylation. At the first step, PHAA transforms to poly(imide benzoxazole) (PIBO) up to 300 °C, while at the second step, the final structure of PBO is formed at 400 °C. Following the changes in the cyclization process, gas transport properties also show the stepwise changes. The significant enlargements of polymer inter-chain distance and free volume cavity radius provide the fundamental understanding for the changes of gas transport properties at the molecular level.

Synthesis and properties of aromatic polyimide, poly(benzoxazole imide), and poly(benzoxazole amide imide)

AbstractTwo series of heterocyclic aromatic polymers were synthesized from 4,4′‐(4,4′‐isopropylidenediphenoxy)bis(phthaltic anhydride) and 2,2′‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride by two‐step method. The inherent viscosities were in the range of 24–45 cm3/g. The effects of the rigid benzoxazole group in the backbone of copolymer on the thermal, mechanical, and physical properties were investigated. These polymers exhibit good thermal stability. The temperatures of 5% weight loss (T5) of these polymers are in the range of 403–530°C in air and 425–539°C in nitrogen. The chard yields of these polymers are in the range of 15–24% in air and 54–61% in nitrogen. These polymers also have high glass‐transition temperatures and a low coefficient of thermal expansion and good mechanical properties. The poly(benzoxazol imide) has a higher tensile strength and modulus than those of neat polyimide. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Hydroxyamide-containing Positive-type Photosensitive Polyimides

A hydroxyamide-containing tetracarboxylic dianhydride was synthesized from trimellitic anhydride chloride and bis(3-amino-4-hydroxyphenyl)sulfone. Poly(amic acid)s (PAAs) were prepared from this dianhydride with several diamines in N-methyl-2-pyrrolidone (NMP). The reflux of the PAA solutions at 160°C for 3 h allowed to form hydroxyamide-containing polyimides (PHAIs) highly soluble in common organic solvents such as NMP. The PHAI films could be completely converted to poly(benzoxazole imide)s (PBOIs) through cyclodehydration of the hydroxyamide groups upon heat treatment at 300°C. The thermally cured PBOI films showed a high Tg ranging 298-323&degC. Other PBOI film properties are also discussed in this paper. The PHAI films were highly transparent at 435 nm but not at 365 nm. This is a problem to be solved for high sensitivity patterning at i-line. The solubility of the PHAI films in TMAH could be controlled by copolymerization using different diamines. The PHAI copolymer films dispersing diazonaphthoquinone (DNQ) as a photosensitizer were uv-irradiated through a photo-mask. Development using a 2.38 wt% TMAH aqueous solution containing 2-propanol gave a fine positive-type pattern with L&S = 20 μm.

Synthesis and characterization of novel aromatic poly(imide–benzoxazole) copolymers

AbstractNew poly(imide–benzoxazole) copolymers were prepared directly from a dianhydride, a diacid chloride, and a bis(o‐diaminophenol) monomer in a two‐step method. In the first step, poly(amic acid–hydroxyamide) precursors were synthesized by low‐temperature solution polymerization in an organic solvent. Subsequently, the thermal cyclodehydration of the poly(amic acid–hydroxyamide) precursors at 350 °C produced the corresponding poly(imide–benzoxazole) copolymers. The inherent viscosities of the precursor polymers were around 0.19–0.33 dL/g. The cyclized poly(imide–benzoxazole) copolymers had glass‐transition temperatures in the range of 331–377 °C. The 5% weight loss temperatures ranged from 524 to 535 °C in nitrogen and from 500 to 514 °C in air. The poly(imide–benzoxazole) copolymers were amorphous, as evidenced by the wide‐angle X‐ray diffraction measurements. The structures of the precursor copolymers and the fully cyclized copolymers were characterized by Fourier transform infrared, 1H NMR, and elemental analysis. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6020–6027, 2005

Novel positive‐working and aqueous‐base‐developable photosensitive poly(imide benzoxazole) precursor

AbstractA novel positive‐working and aqueous‐base‐developable photosensitive poly(imide benzoxazole) precursor based on a poly(amic acid hydroxyamide) bearing phenolic hydroxyl groups and carboxylic acid groups, a diazonaphthoquinone (DNQ) photosensitive compound, and a solvent was developed. Poly(amic acid hydroxyamide) was prepared through the polymerization of 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane, trimellitic anhydride chloride, and 4,4′‐oxydibenzoyl chloride. Subsequently, the thermal cyclization of the poly(amic acid hydroxyamide) precursor at 350 °C produced the corresponding poly(imide benzoxazole). The inherent viscosity of the precursor polymer was 0.17 dL/g. The cyclized poly(imide benzoxazole) showed a high glass‐transition temperature of 372 °C and 5% weight loss temperatures of 535 °C in nitrogen and 509 °C in air. The structures of the precursor polymer and the fully cyclized polymer were characterized with Fourier transform infrared and 1H NMR. The photosensitive polyimide precursor containing 25 wt % DNQ photoactive compound showed a sensitivity of 256 mJ/cm2 and a contrast of 1.14 in a 3‐μm film with a 0.6 wt % tetramethylammonium hydroxide developer. A pattern with a resolution of 5 μm was obtained from this composition. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5990–5998, 2004

A novel synthesis method for the preparation of aromatic poly(imide benzoxazole) from trimellitic anhydride chloride and bis(o‐aminophenol)

AbstractA poly(imide benzoxazole) was prepared directly from trimellitic anhydride chloride and 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane (BisAPAF) monomers in a two‐step method. In the first step, a poly(hydroxyamide amic acid) precursor was synthesized by the low‐temperature solution polymerization in an organic solvent. Subsequently, thermal cyclodehydration of the poly(hydroxyamide amic acid) precursor at 350°C produced the corresponding poly(imide benzoxazole). The inherent viscosity of the precursor polymer was 0.22 dL/g. The cyclized poly(imide benzoxazole) showed a glass transition temperature (Tg) at 329°C and a 5% weight loss temperature at 530°C in nitrogen and at 525°C in air. The poly(imide benzoxazole) is amorphous as evidenced by the wide‐angle X‐ray diffraction measurement. The structures of the precursor polymer and the fully cyclized polymer were characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance spectroscopy (1H NMR). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2388–2391, 2003

ChemInform Abstract: Can an Aromatic Ring Alter the Reactions of a Nearby Unsaturated Imide? A Study of the Rate and Selectivity of Nitrile Oxide Cycloaddition Reactions of Acryloyl Derivatives of the Rebek Imide Benzoxazole.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Can an aromatic ring alter the reactions of a nearby unsaturated imide? A study of the rate and selectivity of nitrile oxide cycloaddition reactions of acryloyl derivatives of the Rebek imide benzoxazole

Cycloadditions of acryloyl derivatives of the Rebek imide benzoxazole are extraordinarily stereoselective, but have rates and regioselectivities that otherwise parallel those of a simple achiral model. It appears that the benzoxazole ring of these compounds completely shields the inner face of the nearby alkene, but has no measurable effect on the rate of reactions on the outer face.

Synthesis and Characterization of New Fluorinated Poly(Imide Benzoxazole)S

We have prepared a series of fluorinated aromatic poly(ether imide benzoxazole)s (PEIBs) and fluorinated aromatic poly(imide benzoxazole)s (PIBs). New PEIBs were prepared by polycondensation of aromatic diamines containing both benzoxazole and hexafluoroisopropylidene groups. New PIBs were prepared by polycondensation of bis( o-aminophenol)s, such as 3,3′-dihydroxybenzidine or 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, with diacid chlorides containing both imide and hexafluoroisopropylidene groups. We have characterized the solubility, film forming ability, thermal stability and dielectric constant of these fluorinated poly(imide benzoxazole)s.

Fluorinated poly(benzoxazole–imide)s

AbstractNew poly(benzoxazole–imide)s have been prepared by polycondensation of bis(o‐aminophenol)s, such as 3,3′ dihydroxybenzidine or 2,2‐bis(3‐amino‐4‐hydroxyphenyl)‐hexafluoropropane, with diacid chlorides containing both imide and hexafluoroisopropylidene groups. The soluble polymer precursor resulting from the first step of polycondensation in N‐methylpyrrolidinone (NMP) at low temperature was processed into thin flexible films, which were then thermally treated to reach the fully cyclized structure of poly(benzoxazole–imide)s, as observed by infrared spectra. An alternative way to produce the cyclization was by heating at reflux the solution of polymer precursor in NMP. Thermal stability, glass transition temperature, dielectric constant and its dependence on relative humidity have been studied and compared with those of related polybenzoxazoles and other heterocyclic Polymers.

Benzheterocycle–imide and amide–imide fibers derived from diacid chlorides containing preformed imide groups

AbstractFibers of benzoxazole–imide ordered copolymers were prepared by cyclodehydrating the amide–phenol units of precursor polyamide–o‐hydroxyimide fibers at 375°C in nitrogen. The precursor polyamide–o‐hydroxyimides were obtained by the reaction of 3,3′‐dihydroxybenzidine with diacid chlorides containing preformed imide rings. The benzoxazole–imide fibers are very thermally stable, especially with respect to retention of tensile properties after heat aging in air. For example, the benzoxazole–imide fibers after heating aging in air for 35 days retained 75% or more of their original tenacities and 50% or more of their original elongations to break. The original fibers did not have high tenacities, probably because of the rather extreme thermal treatment required to cyclodehydrate the amide–phenol units of the precursor fiber. The ultraviolet light stability of one benzoxazole–imide fiber was outstanding for a fiber of the polyheterocycle type: there was no loss in strength or elongation after 140 hr of exposure in a Fade‐Ometer. Fibers of ordered amide–imide polymers based on the same imide‐containing diacid chlorides used for the benzoxazole–imide polymers were also prepared. They were substantially less thermally stable than their benzoxazole–imide fiber counterparts, as expected.