Been-Yang Liaw

Synthesis and properties of new polyamides and polyimides derived from 2,2'-dimethyl-4,4'-bis(4-aminophenoxy)biphenyl

Abstract In this work, we synthesised a new diamine containing noncoplanar 2,2′-dimethyl-biphenylene and flexible aryl ether units, 2,2′-dimethyl-4,4′-bis(4-aminophenoxy)biphenyl (DBAPB), by nucleophilic substitution of 2,2′-dimethylbiphenyl-4,4′-diol with p -chloronitrobenzene in the presence of K 2 CO 3 , followed by catalytic reduction with hydrazine/PdC system. A series of aromatic polyamides having inherent viscosities of 1.03–1.48 dl g −1 were prepared by direct polycondensation with aromatic dicarboxylic acids using triphenyl phosphite and pyridine as condensing agents. Nearly all of the polymers revealed an amorphous nature and were readily soluble in a variety of organic solvents. These polymer films had a tensile strength ranging from 22 to 65 MPa. The glass transition and melting temperature of these polyamides could be determined by d.s.c. and ranged from 226 to 273°C and 392–438°C, respectively. These polyamides remained fairly stable up to a temperature around or below 400°C. Moreover, 10% mass losses were recorded in the range 467–496°C in nitrogen atmosphere. The new polyimides were synthesised from DBAPB and various aromatic tetracarboxylic dianhydrides by the conventional two-step method which involved ring-opening polyaddition to form poly(amic acid)s and subsequently thermal or chemical cyclodehydration to polyimides. The inherent viscosities of poly(amic acid)s and polyimides were in the range 1.32–2.01 and 0.82–1.10 dl g −1 , respectively. These polyimide films had a tensile strength range of 83–139 MPa. These polyimides had glass transition temperatures between 239 and 303°C. Thermogravimetric analyses demonstrated that almost all polymers were stable up to 450°C, and the 10% mass loss temperatures were recorded in the range 488–534°C in nitrogen.

Synthesis and characterization of novel polyamide‐imides containing noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit

A new diimide-dicarboxylic acid, 2,2′-dimethyl-4,4′-bis(4-trimellitimidophenoxy)biphenyl (DBTPB), containing a noncoplanar 2,2′-dimethyl-4,4′-biphenylene unit was synthesized by the condensation reaction of 2,2′-dimethyl-4,4′-bis(4-minophenoxy)biphenyl (DBAPB) with trimellitic anhydride in glacial acetic acid. A series of new polyamide-imides were prepared by direct polycondensation of DBAPB and various aromatic diamines in N-methyl-2-pyrrolidinone (NMP), using triphenyl phosphite and pyridine as condensing agents. The polymers were produced with high yield and moderate to high inherent viscosities of 0.86–1.33 dL · g−1. Wide-angle X-ray diffractograms revealed that the polymers were amorphous. Most of the polymers exhibited good solubility and could be readily dissolved in various solvents such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide, pyridine, cyclohexanone, and tetrahydrofuran. These polyamide-imides had glass-transition temperatures between 224–302 °C and 10% weight loss temperatures in the range of 501–563 °C in nitrogen atmosphere. The tough polymer films, obtained by casting from DMAc solution, had a tensile strength range of 93–115 MPa and a tensile modulus range of 2.0–2.3 GPa.

Synthesis and characterization of new polyamides and polyimides prepared from 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane

In this work, we synthesized a new diamine containing a pendant adamantane group and a flexible aryl ether unit, 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane (BAPA) in three steps starting from 2-adamantanone. A series of new polyamides having inherent viscosities of 0.72-0.90 dL.g -1 were prepared by direct polycondensation with aromatic dicarboxylic acids using triphenyl phosphite and pyridine as condensing agents. All polymers revealed an amorphous nature and were almost readily soluble in a variety of polar solvents. The glass transition temperature of these polyamides range from 254-294°C. The polyamides remain fairly stable up to a temperature around 450°C and lose 10% weight between 490 and 524°C in nitrogen atmosphere. A series of new polyimides were also synthesized from BAPA and various aromatic tetracarboxylic dianhydrides by the conventional two-step method. The inherent viscosities of polyimides were in the range of 0.66-0.77 dL.g -1 . The polyimides are amorphous and have glass transition temperatures between 276 and 310°C. Thermogravimetric analyses demonstrated that almost all polymers are stable up to 450 °C, and the 10% weight loss temperatures were recorded in the range of 515 to 541°C in nitrogen.

Synthesis and properties of polyimides derived from 1,4‐bis(4‐aminophenoxy)2,5‐di‐tert‐butylbenzene

Novel aromatic polyimides containing symmetric, bulky di-tert-butyl substituents unit were synthesized from 1,4-bis(4-aminophenoxy)2,5-di-tert-butylbenzene (BADTB) and various aromatic tetracarboxylic dianhydrides by the conventional two-stage procedure that included ring-opening polyaddition in a polar solvent such as N,N-dimethylacetamide to give poly(amic acid)s, followed by cyclodehydration to polyimides. The diamine was prepared through the nucleophilic displacement of 2,5-di-tert-butylhydroquinone with p-chloronitrobenzene in the presence of K2CO3, followed by catalytic reduction. Depending on the dianhydrides used, the poly(amic acid)s obtained had inherent viscosities of 0.83–1.88 dL g−1. Most of the polyimides formed transparent, flexible, and tough films. Tensile strength and elongation at break of the BADTB-based polyimide films ranged from 68–93 MPa and 7–11%, respectively. The polyimide derived from 4,4′-hexafluoro-isopropylidenebisphathalic anhydride had better solubility than the other polyimides. These polyimides had glass transition temperatures between 242–298°C and 10% mass loss temperatures were recorded in the range of 481–520°C in nitrogen.

Synthesis and characterization of novel poly(amide‐imide)s containing hexafluoroisopropylidene linkage

A series of novel soluble poly(amide-imide)s were prepared from the diimide-dicarboxylic acid, 2,2-bis[N-(4-carboxyphenyl)-phthalimidyl]hexafluoropropane, with various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone containing CaCl 2 using triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 0.78-1.63 dL g -1 . The polymers were amorphous and readily soluble in aprotic polar solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide as well as in less polar solvents such as pyridine and y-butyrolactone, and also in tetrahydrofuran. The polymer films had tensile strength of 84-129 MPa, an elongation at break range of 6-22%, and a tensile modulus range of 2.0-2.7 GPa. The glass transition temperatures of the polymers were determined by DSC method and they were in the range of 240-282°C. These polymers were fairly stable up to a temperature around or above 400°C, and lose 10% weight in the range of 450-514°C and 440-506°C in nitrogen and air, respectively.

Synthesis and characterization of new cardo polyamides and polyimides containing tert-butylcyclohexylidene units

A new cardo diamine monomer, 1,1-bis[4-(4-aminophenoxy)phenyl]-4-tert-butylcyclohexane containing tert-butylcyclohexylidene units was prepared in three steps from 4-tert-butylcyclohexanone. The monomer was reacted with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to produce polyamides and polyimides, respectively. All the polymers, characterized by X-ray diffraction, are amorphous. These cardo polymers exhibit good solubility in a variety of solvents. Almost all polymers are soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), pyridine, and even in tetrahydrofuran (THF) and cyclohexanone. The polymers show glass transition temperatures between 244-310°C. and decomposition temperatures at 10% mass loss ranging from 486-526°C in nitrogen. The tough and flexible polymer films have tensile strength of 77-137 MPa, elongations at breaks of 5-14% and tensile moduli of 2.0-2.6 GPa.

Synthesis and characterization of new soluble polyesters derived from various cardo bisphenols by solution polycondensation

A series of new polyesters was prepared from terephthaloyl (or isophthaloyl) chloride acid with various cardo bisphenols on solution polycondensation in nitrobenzene using pyridine as hydrogen chloride quencher at 150 °C. These polyesters were produced with inherent viscosities of 0.32–0.49 dL · g−1. Most of these polyesters exhibited excellent solubility in a variety of solvents such as N,N-dimethylformamide, tetrahydrofuran, tetrachloroethane, dimethyl sulfoxide, N,N-dimethylacetamide, N-methyl-2-pyrrolidinone, m-cresol, and o-chlorophenol. The polyesters containing cardo groups including diphenylmethylene, tricyclo[5.2.1.02,6]decyl, tert-butylcyclohexyl, phenylcyclohexyl, and cyclododecyl groups exhibited better solubility than bisphenol A–based polyesters. These polymers showed glass transition temperatures (Tgs) between 185 °C and 243 °C and decomposition temperatures at 10% weight loss ranging from 406 °C to 472 °C in nitrogen. These cardo polyesters exhibited higher Tgs and better solubility than bisphenol A-based polyesters.

Synthesis and characterization of new poly(amide–imide)s from 1,4‐bis(4‐trimellitimidophenoxy)‐2‐tert‐butylbenzene with various diamines

New poly(amide–imide)s were prepared from a diimide–dicarboxylic acid, 1,4-bis(4-trimellitimidophenoxy)-2-tert-butylbenzene (BTTB), with various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. The new diimide–dicarboxylic acid BTTB containing an ether linkage and tert-butyl substituent was synthesized by the condensation reaction of 1,4-bis(4-aminophenoxy)-2-tert-butylbenzene with trimellitic anhydride. All the polymers were obtained in quantitative yields with inherent viscosities of 0.62–1.06 dL g−1. The polymers were amorphous, and most of them were readily soluble in aprotic polar solvents such as NMP, N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF), as well as in less polar solvents such as dimethyl sulfoxide (DMSO), m-cresol, pyridine, and γ-butyrolactone, and also even in tetrahydrofuran. The glass transition temperatures of the polymers were determined by DSC method, and they were in the range of 238–279°C. These polymers were stable up to 408–449°C in air and 451–483°C in nitrogen and lose 10% weight in the range of 479–525°C in air and 480–528°C in nitrogen atmosphere. The polymer films had a tensile strength range of 71–115 MPa, an elongation at break range of 4–14%, and a tensile modulus range of 2.3–3.1 GPa.

Synthesis and Characterization of New Cardo Polyamides and Polyimides bearing a 4-Phenylcyclohexylidene Unit

A new cardo diamine monomer, 1,1-bis [4-(4-aminophenoxyl) phenyl]-4-phenylcyohexane bearing a 4-phenylcyclohecylidene unit, was prepared in three steps from -4phenylcyoheanone. The monomer was reacted with various aromatic dicatboxilic acids and tetracarboxylic dianhydrides to produce novel polyamides and polyamides, respectively. The polyamides were prepared utizing Yamazaki reaction conditions with inherent viscosities of 0.62-0.98 dL . g -1 . The polyamides were prepared by a two-stage procedure that included a ringopening polyaddition to give poly(amic acids)s, followed by thermal or chemical cyclodehydration. By chemical cyclodehydratation, the obtained polyimides had inherent viscosities of 0.61-0.93 dL . g -1 . Most of the polymers dissolved in N,N-dimethylformamide dimethyl sulfoxide, pyridine, and cyclohexanone. These polymers showed glass transition temperatures between 225-312°C and decomposition temperatures at 10% weight loss temperatures ranging from 470-500°C and 480-510°C in nitrogen and air atmosphere, respectively. These tough and flexible polymer films had a tensile strenght of 81-124 MPa, an elongation at break of 8-21%, and tensile modulus of 2.0-2.8 GPa.

Synthesis and characterization of new cardo polyamides derived from 8,8‐bis[4‐(4‐aminophenoxy)phenyl]tricyclo[5.2.1.02,6]decane

A series of novel cardo polyamides were prepared by direct polycondensation of 8,8-bis[4-(4-aminophenoxy)phenyl]tricyclo[5.2.1.0 2,6 ]decane and various aromatic dicarboxylic acids in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. The polymers were produced with high yield and moderate to high inherent viscosities of 0.71-1.40 dL. g -1 . Nearly all the polymers could be readily dissolved in polar aprotic solvents such as NMP, N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide, dimethyl sulfoxide as well as less polar solvents such as pyridine and γ-butyrolactone. The polymers were solution-cast from DMAc solution into transparent, flexible, and tough films which were further characterized by X-ray and mechanical analysis. Nearly all the polymers were amorphous, and the polyamide films had a tensile strength range of 97-111 MPa, an elongation at break range of 9-11%, and a tensile modulus range of 1.9-2.3 GPa. The polyamides had glass transition temperatures between 251-272°C and 10% weight loss temperatures in the range of 468-490 and 499-532°C in nitrogen and air atmosphere, respectively.