Yaw-Terng Chern

Preparation and properties of polyamides and polyimides derived from 1,3-diaminoadamantane

1,3-Diaminoadamantane (I) was used as a monomer with various aromatic dicarboxylic acyl chlorides and dianhydrides to synthesize polyamides and polyimides, respectively. Polyamides having inherent viscosities of 0.10-0.27 dL/g were prepared by low-temperature solution polycondensation. The polyamides were soluble in a variety of solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), pyridine, dioxane, and nitrobenzene. These polyamides had glass transition temperatures in the 179-187°C range and 5% weight loss temperatures occurred at up to 354°C. Polyimides based on diamine I and various aromatic dianhydrides were synthesized by the two-stage procedure that included ring-opening to form polyamic acids, followed by thermal conversion to polyimides. The polyamic acids had inherent viscosities of 0.14-0.38 dL/g. The glass transition temperature of these polyimides were in the 245-303°C range and showed almost no weight loss up to 350°C under air and nitrogen atmosphere.

Low dielectric constant polyimides derived from 1, 3-bis(4-aminophenyl)adamantane

This work describes the synthesis of new adamantane-based polyimides by reaction of 1,3-bis(4-aminophenyl)adamantane (4) with various aromatic tetracarboxylic dianhydrides (5). The films have low dielectric constants ranging from 2.76 to 2.92. The poly(amic-acid)s 6 have inherent viscosities of 0.98∼1.42 dL/g. The polyimide 7 d is soluble in o-chlorophenol, m-cresol, chloroform and cyclohexanone. The inherent viscosity and number-average molecular weight of polyimide 7 d is 0.61 dL/g and 45 000, respectively. The films from 7 have tensile strengths of 69.7-110.8 MPa, elongation to breakage values of 2.1∼11.3%, and initial moduli of 2.0-2.3 GPa. Dynamic mechanical analysis (DMA) reveals that most polyimides 7 have two transitions. However, another subglass transition appears at 300°C in the extremely rigid polyimide 7 a . The glass transition temperatures of most polyimides 7, except 7 e and 7 f , exceed 360 °C according to DMA and DSC.

The intrinsic redox reactions of polyamic acid derivatives and their application in hydrogen peroxide sensor.

Polyamic acids (PAAs) containing benzothiazole (BT) and benzoxazole (BO) pendent groups (PAA-BT and PAA-BO, respectively) which possessed electroactivity were synthesized successfully. The addition of H(2)O(2) chemically oxidized the intrinsic carboxylic acid groups of PAA to form peroxy acid groups, and the peroxy acid further oxidized the electroactive sites of BT and BO to form N-oxides. The N-oxides could be reverted to their original form by electrochemical reduction, thus increasing the electrochemical reductive current. Based on this mechanism, enzyme-free hydrogen peroxide (H(2)O(2)) biosensors were prepared by modifying gold electrodes with the PAA derivatives (PAA-BT/Au and PAA-BO/Au, respectively). These biosensors had rapid response times (3.9-5.2 s) and high selectivity and sensitivity (280.6-311.2 μA/mM-cm(2)). A comparison of the PAA-BT/Au and PAA-BO/Au electrodes with electrodes prepared using polyamide-BT or polyamide-BO (i.e., lacking the carboxylic acid groups) confirmed the mechanism by which PAA derivatives detect H(2)O(2). Modifying the surface morphology of the electrode from a planar to a three-dimensional (3D) configuration enhanced the performance of the PAA-BO/Au electrode. The sensitivity of the 3D-PAA-BO/Au electrode was 1394.9 μA/mM-cm(2), ∼ 4.5 times higher than that of the planar electrode. The detection limit was also enhanced from 5.0 to 1.43 μM. The biosensor was used analytically to detect and measure H(2)O(2) in urine samples collected from healthy individuals and patients suffering from noninvasive bladder cancer. The results were promising and comparable to that measured by a classical HPLC method, which verified the developed biosensor had a potential to provide a usefully analytical approach for bladder cancer.

Synthesis and characterization of new polyamides containing adamantyl and diamantyl moieties in the main chain

This work synthesized a series of new polyamides by direct polycondensation of 1,3-bis[4-(4-carboxyphenoxy)phenyl]adamantane (I) with various diamines. The diacid I was synthesized from 1,3-bis(4-hydroxyphenyl)adamantane in two steps. Polyamides III were soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and pyridine. The polyamides had medium inherent viscosities of 0.30–0.55 dL/g and number-average molecular weights (Mn) of 22,000–36,000. The polyamides IIIa and IIIb had tensile strengths of 59.8 and 77.5 MPa, elongation to breakage values of 5.8 and 7.6%, and initial moduli of 1.9 and 1.8 GPa, respectively. Their glass transition temperatures were found to be 219–295°C by means of differential scanning calorimetry (DSC). Dynamic mechanical analysis (DMA) reveals that the incorporation of rigid and bulky diamantane into polyamides IIIa and IIIb leads to high glass transition temperatures (Tgs), at 299 and 286°C, respectively. The decomposition temperatures of polyamides III at a 5% weight loss ranged from 388 to 416°C in air and from 408 to 435°C in N2 atmosphere.

In vitro Antitumor and Antimicrobial Activities of N-Substituents of Maleimide by Adamantane and Diamantane

New N-1-adamantylcitraconimide (compound 1) and N-1-diamantylcitraconimide (compound 2) were synthesized by reaction of citraconic anhydride with 1-aminoadamantane, and 1-aminodiamantane, respectively, followed by imidization with acetic anhydride and sodium acetate. Compound 1, N-1-adamantylmaleimide (compound 3) and N-1-diamantylmaleimide (compound 4) exhibited strong growth-inhibitory activity against four cancer cell lines (Colo 205, Hep G2, SK-BR-3 and Molt-4). Moreover, compound 1 showed relatively specific cytotoxicity against the test tumor cell lines. Compound 2 exhibited growth inhibitory activity against Colo 205, and SK-BR-3 cells, similar to 5-fluorouracil. It was noted that compound 2 showed relatively low cytotoxicity against Molt-4 cells, approximately 42 times lower than 5-fluorouracil. The N-substituents of imides with adamantly substituents have a more potent antitumor activity than the imides with diamantyl substituents. The imides with methyl substituents (compounds 1 and 2) showed relatively higher selectivity against the tested cancer cell lines than the imides without methyl substituents (compounds 3 and 4). Compounds 3 and 4 show good in vitro activities against Staphylococcus aureus and Trichophyton mentagrophytes. Compound 1 had weak antimicrobial activity against T. mentagrophytes.

Synthesis and properties of new adamantane-based poly(ether imide)s

A new adamantane-based bis(ether anhydride), 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]adamantane dianhydride, was prepared in three steps starting from nitrodisplacement of 4-nitrophthalonitrile with the potassium phenolate of 2,2-bis(4-hydroxyphenyl)adamantane. A series of adamantane-containing poly(ether imide)s were prepared from the adamantane-based bis(ether anhydride) and aromatic diamines by a conventional two-stage synthesis in which the poly(ether amic acid)s obtained in the first stage were heated stage-by-stage at 150–270°C to give the poly(ether imide)s. The intermediate poly(ether amic acid)s had inherent viscosities between 0.56 and 1.92 dL/g. Except for those from p-phenylenediamine, m-phenylenediamine, and benzidine, all the poly(ether amic acid) films could be thermally converted into transparent, flexible, and tough poly(ether imide) films. All the poly(ether imide)s showed limited solubility in organic solvents, although they were amorphous in nature as evidenced by X-ray diffractograms. Glass transition temperatures of these poly(ether imide)s were recorded in the range of 242–317°C by differential scanning calorimetry and of 270–322°C by dynamic mechanical analysis. They exhibited high resistance to thermal degrdation, with 10% weight loss temperatures being recorded between 514–538°C in nitrogen and 511–527°C in air.

Synthesis and characterization of new polyesters derived from 1,6- or 4,9-diamantanedicarboxylic acyl chlorides with aryl ether diols

A series of new polyesters was synthesized by high-temperature solution polycondensation of 1,6- or 4,9-diamantanedicarboxylic acyl chlorides with aryl ether diols. All polyesters had good solubilities and could be soluble in chloroform, nitrobenzene, o -chlorophenol, N -dimethylformamide (DMF), and o -dichlorobenzene. Number-average molecular weights ( M n ) of polyesters IV and V were 40 000∼280 000 and 48 000∼150 000, respectively. The glass transition temperatures of polyesters were 90–108°C and 102–132°C, as determined by differential scanning calorimetry (d.s.c.) and dynamic mechanical analysis (DMA), respectively. The temperatures at 5% weight loss of polyesters ranged from 338 to 395°C in air and from 385 to 403°C in N 2 atmosphere. Polyesters had tensile strengths of 34.9∼45.5 MPa, elongation to breakage values of 3.5∼4.6%, and initial moduli of 1.4∼1.6 GPa.

Synthesis and characterization of new polyamides derived from 1,3‐bis[4‐(4‐aminophenoxy)phenyl]adamantane

Several new polyamides were synthesized by direct polycondensation of the 1,3-bis[4-(4-aminophenoxy)phenyl]adamantane (I) with various dicarboxylic acids. The polyamides had inherent viscosities and number-average molecular weights (Mn) of 0.46–0.96 dL/g and 28,000–109,000, respectively. All polyamides III had good solubilities and were soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and pyridine. Polyamides had tensile strengths of up to 72.3 MPa, elongation to breakage values of up to 10.2%, and initial modulus of up to 2.1 GPa. Their glass transition temperatures were found to be 228–269°C and 252–307°C using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA), respectively. The melting temperature of IIIf was observed at 318°C using DSC. The temperatures of polyamides III at a 5% weight loss ranged from 395 to 435°C in air and from 400 to 450°C in a N2 atmosphere.

Preparation and properties of new polyimides derived from 1,6-diaminodiamantane

New polyimides containing diamantane units were prepared by a conventional two-step method starting from 1,6-diaminodiamantane and aromatic dianhydrides. The intermediate poly(amic acid)s had inherent viscosities of 0.33–0.55 dL/g. These polyimides did not decompose below 400°C in air or nitrogen atmosphere, and the temperature at 5% weight loss were above 491°C. The glass transition temperatures of the polyimides were found to be 375–429°C by DSC. These polyimides had almost the same semicrystalline patterns and exhibited crystalline diffraction peak (2 θ) at around 15°. The polyimide Vb exhibited a melting endothermic peak at 514°C.

Synthesis and Properties of New Polyarylates from 1,4-Bis(4-carboxyphenoxy)naphthyl or 2,6-Bis(4-carboxyphenoxy)naphthyl and Various Bisphenols

New 1,4-naphthyl and 2,6-naphthyl-containing polyarylates having inher- ent viscosities up to 1.28 dL/g were synthesized by the high-temperature solution polycondensation from the acid chloride of 1,4-bis(4-carboxyphenoxy)naphthyl or 2,6- bis(4-carboxyphenoxy)naphthyl and various bisphenols. Most of the resulting polyary- lates showed amorphous characteristics and were readily soluble in common organic solvents such as N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), o- chlorophenol, and chloroform. Transparent, flexible, and colorless films of these poly- mers could be cast from the DMAc solutions. Their cast films had tensile strengths ranging from 54.9 to 84.2 MPa, elongations at break from 5.3% to 19.0%, and initial modulus from 2.0 to 2.8 GPa. These polymers had glass transition temperatures in the range of 172-280°C and began to lose weight around 400°C, with 10% weight loss being recorded at about 450°C in air. Dynamic mechanical analysis (DMA) reveals that the polyarylates containing isopropylidene linkages have three transitions on the temper- ature scale between 2100 and 300°C. However, only two transitions were observed in the other polyarylates without isoproylidene linkage.