Synthesis and thermal characterization of novel poly(tetramethyl-1,3-silphenylenesiloxane) derivative bearing adamantyl moiety

A novel poly(tetramethyl-1,3-silphenylenesiloxane) derivative having adamantyl moiety, i.e., poly(tetramethyl-5-adamantyl-1,3-silphenylenesiloxane) (P1) was synthesized by solution polycondensation of a novel disilanol monomer, i.e., 1-[3,5-(dimethylhydroxysilyl)phenyl]adamantane (M1). M1 was prepared by the Grignard reaction using chlorodimethylsilane and 1-(3,5-dibromophenyl)adamantane, followed by the hydrolysis catalyzed by 5% palladium on charcoal. P1 exhibited the good solubility in common organic solvents, such as tetrahydrofuran (THF), chloroform, dichloromethane, benzene, and toluene at ambient temperature. P1 was also soluble in hot hexane, diethyl ether, and ethyl acetate. The glass transition temperature (T _g) and temperature at 5% weight loss (T _d5) of P1 were 85 and 517 °C, respectively, and much higher than those of poly(tetramethyl-1,3-silphenylenesiloxane), indicating that P1 is a new polysiloxane derivative with good solubility as well as good thermostability.     

Synthesis and properties of novel poly(tetramethylsilnaphthylenesiloxane) derivatives

Novel poly(tetramethylsilnaphthylenesiloxane) derivatives were synthesized and characterized by differential scanning calorimetry (DSC), thermogravimetry (TG), and X-ray diffraction analyses. Poly(tetramethylsilnaphthylenesiloxane) derivatives were obtained by condensation polymerization of the corresponding disilanol derivatives, i.e. 1,4-, 1,5-, 2,6-, and 2,7-bis(dimethylhydroxysilyl)naphthalenes, which were prepared by the Grignard reaction using chlorodimethylsilane and the corresponding dibromonaphthalene derivatives followed by the hydrolyses, catalyzed by palladium on charcoal. The obtained poly(tetramethyl-1,5-silnaphthylenesiloxane) was insoluble in common organic solvents; however, the other polymers exhibited the good solubility in common organic solvents, such as tetrahydrofuran (THF), chloroform, dichloromethane, and toluene. The introduction of tetramethyl-1,5-silnaphthylenesiloxane units into the resulting polymer was confirmed by ¹H NMR spectrum of the copolymer obtained by condensation copolymerization of 1,5-bis(dimethylhydroxysilyl)naphthalene with 1,4-bis(dimethylhydroxysilyl)naphthalene. It was revealed from the DSC and X-ray diffraction measurements that poly(tetramethyl-1,5-silnaphthylenesiloxane) and poly(tetramethyl-2,6-silnaphthylenesiloxane) exhibited the crystallinity; however, poly(tetramethyl-1,4-silnaphthylenesiloxane) and poly(tetramethyl-2,7-silnaphthylenesiloxane) were amorphous. The glass transition temperature (T_g) and the temperature at 5% weight loss (T_d5) of poly(tetramethylsilnaphthylenesiloxane) derivatives with dimethylsilyl group at 1-position of the naphthylene moiety were higher than those at 2-position of the naphthylene moiety. The T_g and melting point (T_m) of the present polymers were higher than those of poly(tetramethyl-1,4-silphenylenesiloxane).     

Synthesis and Characterization of Poly(tetramethyl-1,4-silphenylenesiloxane) Derivatives with Oxyethylene Substituent on Phenylene Moiety

Summary Novel poly(tetramethyl-1,4-silphenylenesiloxane) derivatives having 2-methoxy-ethoxy or 2-(2-methoxyethoxy)ethoxy substituents at both 2- and 5-positions on phenylene moieties were synthesized and characterized by differential scanning calorimetry and thermogravimetry analyses. Poly(tetramethyl-1,4-silphenylene-siloxane) derivatives were obtained by condensation polymerization of the corresponding disilanol derivatives, i.e., 1,4-bis(dimethylhydroxysilyl)-2,5-bis(2-methoxyethoxy)benzene and 1,4-bis(dimethylhydroxysilyl)-2,5-bis[2-(2-methoxy-ethoxy)ethoxy]benzene, which were prepared by the Grignard reaction using chlorodimethylsilane and the corresponding dibromobenzene derivatives followed by the hydrolyses, catalyzed by palladium on charcoal. The introduction of 2-methoxyethoxy groups on the phenylene moiety made the melting point high, compared with poly(tetramethyl-1,4-silphenylenesiloxane); however, that of 2-(2-methoxyethoxy)ethoxy groups made it low, indicating the longer oxyethylene moiety induced the lowering of the melting point. There were no significant differences in the thermostabilities of both present polymers, suggesting the length of oxyethylene moiety would not affect the thermostability, though the introduction of polar oxyethylene group onto the phenylene moiety induced a decline of thermostability.     

Synthesis and characterization of poly(tetramethylsilarylenesiloxane) derivatives bearing benzodithiophene moieties

Poly(tetramethylsilarylenesiloxane) derivatives bearing benzo[1,2-b;4,5-b′]dithiophene (P1) and benzo[2,1-b;3,4-b′]dithiophene (P2) moieties were prepared via polycondensation of the corresponding disilanol monomers, that is, 2,6-bis(dimethylhydroxysilyl)benzo[1,2-b;4,5-b′]dithiophene (M1) and 2,7-bis(dimethylhydroxysilyl)benzo[2,1-b;3,4-b′]dithiophene (M2), respectively. It was deduced that P1 is a crystalline polymer while P2 is an amorphous one from the results of differential scanning calorimetry (DSC). Bathochromic and hyperchromic effects were observed in the absorption and fluorescence spectra when dimethylsilyl substituents were introduced on the benzo[1,2-b;4,5-b′]dithiophene and benzo[2,1-b;3,4-b′]dithiophene skeletons. The fluorescence quantum yields (Φ_Fs) were not improved by the introduction of dimethylsilyl groups onto the benzo[1,2-b;4,5-b′]dithiophene and benzo[2,1-b;3,4-b′]dithiophene skeletons, whereas the improvement in the Φ_Fs was remarkable in the case of poly(tetramethylsilarylenesiloxane) derivatives that possessed the corresponding fused benzene ring systems, i.e., poly(tetramethyl-2,6-silanthrylenesiloxane) and poly(tetramethyl-1,8-silphenanthrylenesiloxane).     

Synthesis and Thermal Characterization of Novel Fluorene-Based Polysiloxane Derivatives

Three novel poly(tetramethylsilfluorenylenesiloxane) derivatives having different substituent at 9-position of fluorenylene moiety, i.e. dimethyl (P1), spirocyclohexyl (P2), and spirofluorenyl (P3) substituents, were obtained by polycondensation of novel three disilanol monomers, i.e. 2,7-bis(dimethylhydroxysilyl)-9,9-dimethyl- fluorene (M1), 2’,7’-bis(dimethylhydroxysilyl)-spiro(cyclohexane-1,9’-fluorene) (M2), 2,7-bis(dimethylhydroxysilyl)-9,9’-spirobifluorene (M3), respectively. P1–P3 exhibited the good solubility in common organic solvents, such as tetrahydrofuran (THF), chloroform, dichloromethane, and toluene. It was suggested from the differential scanning calorimetry (DSC) and the X-ray diffraction analysis that P1 exhibited the crystallinity whereas P2 and P3 were amorphous polymers. The glass transition temperature (T _g) determined by DSC and the temperature at 5% weight loss (T _d5) determined by thermogravimetry (TG) were dependent on the substituent at 9-position on fluorene; both orders of T _g and T _d5 were P3 > P2 > P1, indicating the bulkiness of substituent at 9-position of fluorene resulted in the good thermal stability. It is noteworthy that amorphous P3 exhibiting very high T _g of 156 °C and T _d5 of 535 °C is a new heat-resistant polysiloxane derivative as well as a promising candidate for blue-light-emitting materials.     

Synthesis and thermal characterization of novel adamantane-based polysiloxane

Novel polysiloxane derivative having adamantyl moiety in the main chain (P1) was synthesized and characterized by differential scanning calorimetry (DSC), thermogravimetry (TG), and X-ray diffraction analysis. P1 was obtained by bulk polycondensation without catalysts as well as solution polycondensation of novel disilanol monomer, i.e., 1,3-bis[4-(dimethylhydroxysilyl)phenyl]adamantane (M1), which was prepared by the Grignard reaction using chlorodimethylsilane and 1,3-bis(4-bromophenyl)adamantane, followed by the hydrolysis catalyzed by 5% palladium on charcoal. The molecular weight of P1 was dependent on the concentration of M1 in solution polycondensation, and the high concentration of M1 would result in the high average molecular weight of P1. P1 exhibited the good solubility in common organic solvents, such as tetrahydrofuran (THF), chloroform, dichloromethane, and toluene. The glass transition temperature (T_g) of P1 determined from DSC would be dependent on the average molecular weight of P1. The highest T_g was 115 °C and much higher than that of poly(tetramethyl-1,4-silphenylenesiloxane) (−20 °C). The melting temperature (T_m) of P1 seemed to be independent of the average molecular weight of P1 and was in the range of 153-157 °C, which was comparable to the T_m of poly(tetramethyl-1,4-silphenylenesiloxane). The temperature at 5% weight loss (T_d5) of P1 determined by TG was also comparable to that of poly(tetramethyl-1,4-silphenylenesiloxane), indicating that P1 is a new polysiloxane derivative with the high T_g as well as good thermostability.     

Synthesis and properties of poly(tetramethyl-1,6-silpyrenylenesiloxane) derivative with phenyl groups on pyrenylene moiety

Poly(tetramethyl-1,6-silpyrenylenesiloxane) derivative with phenyl groups on pyrenylene moieties (P1) was prepared via polycondensation of disilanol monomer, i.e. 1,6-bis(dimethylhydroxysilyl)-3,8-diphenylpyrene (M1). P1 exhibited the very high glass transition temperature (T _g) of 191 °C. The temperature at 5% weight loss (T _d5) of P1 was 482 °C, indicating the relatively good thermostability of P1. P1 exhibited the bathochromic effect in the absorption and fluorescence spectra, indicating the expansion of π-conjugation by introducing phenyl groups onto pyrene skeleton as well as the σ–π and σ*–π* conjugation between pyrene and silyl moieties. In addition, P1 exhibited relatively weak excimer emission because of the inhibition of the excimer formation of pyrene skeleton by introduction of bulky phenyl groups onto pyrene skeleton. The fluorescence quantum yields (Φ_Fs) of M1 and P1 in chloroform were determined to be 0.46 and 0.37, respectively. It was revealed that M1 and P1 exhibited the higher fluorescence intensity than 1,6-diphenylpyrene, owing to the effect of the introduction of silyl moieties onto pyrene skeleton.     

Synthesis and optical properties of poly(tetramethylsilarylenesiloxane) derivative bearing diphenylcyclopentadithiophene moiety

The thermal and optical properties of a novel diphenylcyclopentadithiophene-based poly(tetramethylsilarylenesiloxane) derivative (P1), which was prepared via polycondensation of a novel disilanol monomer, i.e., 2,6-bis(dimethylhydroxysilyl)-4,4-diphenylcyclopentadithiophene (M1), were investigated. P1 exhibited good solubility in common organic solvents, such as benzene, toluene, chloroform, dichloromethane and THF at ambient temperature. The glass transition temperature (T_g) of P1 was determined by differential scanning calorimetry to be 109 °C. No melting temperature (T_m) of P1 was observed, indicating the obtained P1 was an amorphous polymer. The temperature at 5% weight loss (T_d5) of P1 was 454 °C, indicating the rather good thermostability of P1. Bathochromic and hyperchromic effects were observed in the absorption and fluorescence spectra by introducing dimethylsilyl substituents onto 4,4-diphenylcyclopentadithiophene skeleton. The fluorescence quantum yields (Φ_Fs) of M1 and P1 in chloroform were determined to be 0.36 and 0.39, respectively. It was revealed that M1 and P1 exhibited the higher fluorescence intensity than diphenylcyclopentadithiophene owing to the cooperative effects of the introduction of diphenyl groups onto spiro carbon of cyclopentadithiophene as well as dimethylsilyl moieties onto 2- and 6-position of cyclopentadithiophene skeleton.     

Synthesis and Structure of Octamethylcyclo-di(meta-silphenylenesiloxane)

Octamethylcyclo-di(meta-silphenylenesiloxane) 1 (cyclic meta-dimer) was synthesized from 1,3-bis(dimethylhydroxysilyl)benzene 7 in a dilute THF solution, in the presence of a catalytic amount of 4-dimethylaminopyridine (DMAP). In contrast, only small amounts of the cyclic meta-dimer 1, cyclic meta-trimer 2, cyclic meta-tetramer, etc. were obtained when the condensation reaction was carried out with the catalyst n-hexylamine 2-ethylhexoate or sodium hydroxide. The major product in these reactions is polymer 8. The structure of compound 1 was confirmed by X-ray crystallography. This cyclic molecule is most likely unstrained since the X-ray structure reveals that the Si–O–Si bond angle is 142.1(1)° which is similar to that in most unstrained siloxane compounds.     

Synthesis and properties of <Emphasis Type="Italic">ortho</Emphasis>-linked aromatic poly(ester-amide)s and poly(ester-imide)s bearing 2,3-bis(benzoyloxy)naphthalene units

Two new naphthalene-ring-containing bis(ester-amine)s, 2,3-bis(4-aminobenzoyloxy)naphthalene (p-2) and 2,3-bis(3-aminobenzoyloxy)naphthalene (m-2), were prepared from the condensation of 2,3-dihydroxynaphthalene with 4-nitrobenzoyl chloride and 3-nitrobenzoyl chloride, respectively, followed by catalytic hydrogenation. The novel aromatic poly(ester-amide)s and poly(ester-imide)s having 2,3-linked bis(benzoyloxy)naphthalene units have been synthesized from the polycondensation reactions of bis(ester-amine)s (p-2 and m-2) or an equimolar mixture of 4,4′-oxydianiline and p-2 or m-2 with various aromatic dicarboxylic acids and dianhydrides. The synthesis of the poly(ester-amide)s was achieved by the phosphorylation polyamidation reaction by means of triphenyl phosphate, and the synthesis of the poly(ester-imide)s included ring-opening polyaddition to give poly(amic acid)s followed by chemical imidization to polyimides. Most of the poly(ester-amide)s were readily soluble in various organic solvents. Six poly(ester-amide)s and two poly(ester-imide)s derived from less rigid diacids and dianhydrides, respectively, were amorphous and could be solution-cast into transparent and tough films with good mechanical properties. Most of the poly(ester-amide)s displayed discernible glass-transition temperatures (T _gs) between 192 and 223 °C in the DSC traces. All of the poly(ester-imide)s, except for one sample, showed clear T _g values between 225 and 265 °C by DSC. These poly(ester-imide)s showed excellent thermal stability with 10 wt% loss temperatures above 460 °C in nitrogen or air.     

Synthesis and characterization of heterocyclic,and optically active poly(amide-imide)s by phosphorylation polycondensation

Summary N,N′-Pyromelliticdiimido-di-L-methionine (1), N,N′-Pyromelliticdiimido-di-L-alanine (2), N,N′-Pyromelliticdiimido-di-L-phenylalanine (3) , and N,N′-Pyromelliticdiimido-di-L-leucine (4) were prepared from the reaction of Pyromellitic dianhydride with corresponding L-amino acids in a mixture of glacial acetic acid and pyridine solution (3/2 ratio) under refluxing conditions. The phosphorylation polycondensation of the corresponding diimide-diacid monomers with 4-phenyl-2,6-bis(4-aminophenyl) pyridine (6) or 4-(p-methylthiophenyl)-2,6-bis(4-aminophenyl) pyridine (8) were carried out in N-methyl-2-pyrolidone (NMP). The resulting poly (amide-imide)s were obtained in quantitative yields, showed admirable inherent viscosities (0.20-0.97 dl g^-1), were soluble in polar aprotic solvents, showed good thermal stability and high optical purity. The synthetic compounds were characterized by IR, MS, ¹H NMR and ¹³C NMR spectroscopy, elemental analysis and specific rotation.     

Synthesis of Poly(propargyl esters) with Rhodium Catalysts and Their Characterization

Summary Propargyl esters (HC≡CCH₂OC(=O)R; 1: R = n-C₅H₁₁, 2: R = CH₃, 3: R = CHBrCH₃, 4: R = C₆H₅, 5: R = C(C₆H₅)₃) were polymerized by using (nbd)Rh⁺(η⁶-Ph-B^-Ph₃) (nbd = 2,5-norbornadiene) to produce poly(1)–poly(5) with molecular weights in the range of M_n = 4,900–40,000. Poly(1), poly(3) and poly(4) were readily soluble in common organic solvents such as toluene, THF and CHCl₃, and poly(2) showed similar solubility behavior except that it was insoluble in THF. Poly(5) did not dissolve in any organic solvent. Poly(1) was yellow oil, while poly(2)–poly(5) were yellow solids. Poly(1)–poly(4) exhibited UV-vis absorptions in a range of 300–425 nm, which are attributed to the conjugation of the main chain. All the polymers were thermally stable up to 150–200 °C.     

Synthesis and properties of poly(phenylacetylene)s with pendant imino groups

Summary Polymerization of phenylacetylenes containing imino groups with a variety of transition metal catalysts was investigated. The monomers employed were N-(4-ethynylbenzylidene)aniline (1), N-(3-ethynylbenzylidene)aniline (2), N-(4-ethynylbenzylidene)-2,6-diisopropylaniline (3), N-(4-ethynylbenzylidene)-4-hexylaniline (4), N-(4-ethynylbenzylidene)butylamine (5), and N-(4-ethynylbenzylidene)octylamine (6). All of the monomers smoothly polymerized with [(nbd)RhCl]₂-Et₃N to give polymers in excellent yields, whereas no polymerization took place with W, Mo, and Fe catalysts. The produced polymers were orange to red solids and soluble in common organic solvents except for poly(1). UV-vis spectra of the polymers indicated that the main chains possess a similar degree of conjugation to that of poly(phenylacetylene). However, the stability of polymer backbone toward oxidative cleavage in solution remarkably improved, which is contributed by the electron-withdrawing character of imino groups. Received: 24 August 1999/Accepted: 29 September 1999     

Poly(ether ketone azomethane)s and poly(ether ketone imide)s containing naphthylene moieties

A new diamine monomer, 1,5-bis[4-(4-aminophenoxy)]benzoyl-2,6-dimethoxynaphthalene, was synthesized via a Friedel–Crafts acylation reaction followed by an aromatic nucleophilic substitution reaction. Six ether–ketone linked polymers, named as poly(ether ketone azomethane)s and poly(ether ketone imide)s, were successfully prepared through the polycondensations of the diamine monomer with dialdehydes and dianhydrides, respectively. These naphthylated polymers exhibited high T _g values (142–288 °C), due to their bulky and rigid chemical structure. Meanwhile, they showed good thermal stability and improved solubility. Typically, some of them were casted into thin flexible film and showed high moduli.     

Polymerization by phase transfer catalysis

Poly(amide-carbonate)s and poly(amide-thiocarbonate)s derived from the diphenol-amides N-(2,6-dichloro-4-nitrophenyl)-2,2-bis(hydroxyphenyl)-propylamide (I), N-(2,6-dichloro-4-nitrophenyl)-3,3-bis(hydroxyphenyl)-butylamide (II), and N-(2,6-dichloro-4-nitrophenyl)-4,4-bis(hydroxyphenyl)-pentylamide (III), and phosgene or thiophosgene, have been synthesized under phase transfer conditions using several quaternary ammonium salts as phase transfer catalysts. Benzyltriethylammonium chloride (BTEAC) was effective in practically all cases due the hydrophilicity of this catalysts. Received: 21 February 1997/Revised: 28 April 1997/Accepted: 30 April 1997     

Synthesis and properties of cyclopentadithiophene-based poly(silarylenesiloxane) derivatives

Poly(silarylenesiloxane) derivatives with 4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene moiety, bearing dimethyl- (P1), methylphenyl- (P2) and diphenyl- (P3) substituents on silyl moieties, were prepared via polycondensation of the corresponding disilanol monomers, that is, 2,6-bis(dimethylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M1), 2,6-bis(methylphenylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M2), and 2,6-bis(diphenylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M3), respectively. P1-P3 exhibited the good solubility in common organic solvents, such as benzene, toluene, chloroform, dichloromethane, THF, and so on. The glass transition temperatures (T_gs) of P1, P2 and P3 were determined by differential scanning calorimetry to be 56, 97 and 137 °C, respectively, depending on the substituent on the silyl moieties. No melting temperatures (T_ms) of P1, P2 and P3 were observed, suggesting the obtained P1-P3 are amorphous polymers. The temperatures at 5% weight loss (T_d5s) of P1, P2 and P3 were 460, 459 and 479 °C, respectively, indicating that the larger number of phenyl group on the silyl moieties resulted in the better thermostability. Bathochromic and hyperchromic effects were observed in the absorption and fluorescence spectra by introducing silyl substituents onto 4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene moiety. In addition, the bathochromic shift of the maximum absorption (λ_abs) and the increase in the fluorescence quantum yield (Φ_F) were observed by the introduction of phenyl group onto the silyl moieties.     

Synthesis and Structure of Octamethylcyclo-di(meta-silphenylenesiloxane)

Octamethylcyclo-di(meta-silphenylenesiloxane) 1 (cyclic meta-dimer) was synthesized from 1,3-bis(dimethylhydroxysilyl)benzene 7 in a dilute THF solution, in the presence of a catalytic amount of 4-dimethylaminopyridine (DMAP). In contrast, only small amounts of the cyclic meta-dimer 1, cyclic meta-trimer 2, cyclic meta-tetramer, etc. were obtained when the condensation reaction was carried out with the catalyst n-hexylamine 2-ethylhexoate or sodium hydroxide. The major product in these reactions is polymer 8. The structure of compound 1 was confirmed by X-ray crystallography. This cyclic molecule is most likely unstrained since the X-ray structure reveals that the Si–O–Si bond angle is 142.1(1)° which is similar to that in most unstrained siloxane compounds.     

Pentacoordinated iron(II) complexes with 2,6-bis[(imino)ethyl]pyridine-Schiff base ligands as new catalyst systems mediated atom transfer radical polymerization of (meth)acrylate monomers

2,6-bis[1-(cis)-myrtanylimino)ethyl]pyridineiron(II) chloride (2) and 2,6-bis[(1-phenylimino)ethyl]pyridineiron(II) chloride (3) were investigated as novel complexes for iron-mediated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) and tert-butyl acrylate (tBA) using toluene as the solvent, and ethyl 2-bromoisobutyrate as the initiator. A catalyst/initiator molar ratio as low as 0.1/1 was used in order to reduce catalyst contamination to the polymers. Both complexes produced PMMA and PtBA polymers with controlled structures and very low molecular weight distributions as low as 1.07, in particular for complex 3. High to moderate conversions (30–45%) were obtained in 20 h, although very diluted amount of catalyst was used and in the absence of any reducing agent which indicates an efficient catalyst system. The resulting polymers were characterized by NMR, GPC, and DSC. Syndio-rich atactic poly(t-BA) and poly(MMA) with relatively high [rr] diads (50%, 42%, respectively) were isolated.     

Study of Structure-property Relationships of Poly(benzobisthiazole) and it’s Derivatives

Summary Poly(p-phenylene benzobisthiazole) (PBZT) and a series of new derivatives, poly(benzobisthiazole-1,4-diphenylene etherylene) (PBTPE), poly(bisbenzothiazole-2,2’-phenelyene-6,6’-(4-tert-butyl)cyclohexylidene) (PBTPBCH) and poly(bisbenzothiazole-2,2’-phenelyene etherylene-6,6’-(4-tert-butyl)cyclohexylidene) (PBTPEBCH), were synthesized by polycondensation of 2,5-diamino-1,4-benzenedithiol dihydrochloride (DABDT·2HCl) or 1,1-bis(4-amino-3-mercaptophenyl)-4-tert-butylcyclohexane dihydrochloride (BAMPBCH·2HCl) with terephthalic acid or 4,4’-dicarboxydiphenyl ether in poly (phosphoric acid) (PPA). The inherent viscosity, thermal stability, solubility, morphology and photophysical properties of them were investigated and compared in detail. The introduction of etherylene or 4-tert-butylcyclohexylidene both decreased the inherent viscosity of PBZT. Although the decomposition temperatures of these derivatives were lower than PBZT, they still had good thermal stability. In addition, the thermogravimetric analysis showed PBTPBCH and PBTPEBCH containing 4-tert-butylcyclohexylidene had the lower thermal stability than PBTPE containing etherylene. The solubility of them was all enhanced. Especially, PBTPBCH and PBTPEBCH showed better solubility. X-ray diffractograms of all the derivatives showed that they were amorphous. Compared with PBZT, the absorption maximum (λ_max) of all the derivatives prepared was blue shifted in different degree according to their structure respectively. The excitation and emission peaks were also blue shifted. Furthermore, both of the substituting groups incorporated into the polymer backbone could improve the photoluminescence quantum yield to a certain extent. Finally we established the structure-property relationships of this class of poly(benzothiazole)s by investigating and comparing these properties in detail.     

Thermal Degradation Studies of Poly (Amide-Ester)s

Abstract

The thermal behaviour of poly(amide-ester)s with the amide group in the side chain was studied. Polymers were sinthesized from the diphenol-amides N-(2,6-dichloro-4-nitrophenyl)-2, 2-bis(4-hydroxyphenyl)-propanamide, N-(2, 6-dichloro-4-nitrophenyl)-3,3-bis(4-hydroxyphenyl)-butanamide, and N-(2,6-dichloro-4-nitrophenyl)-4, 4-bis(4-hydroxyphenyl)-pentanamide and terephthaloyl chloride, isophthaloyl chloride and adipoyl chloride under phase-transfer conditions using several phase-transfer catalysts. The thermal decomposition temperature was influenced by both, the nature of the diacid and the length of the side chain, those derived from terephthaloyl chloride being more stable than those derived from isophthaloyl chloride and adipoyl chloride. All polymers degrade in a single-step process and the kinetics parameters were determined using the Arrhenius relationship and a computer program.