Linear polymers with sulfur in the main chain III. Synthesis of polythioesters by polycondensation of bis(4,4′‐mercaptophenyl)sulfide with various acid dichlorides and their properties

Synthesis and properties of sulfur‐containing linear polythioesters derived from bis(4,4′‐mercaptophenyl)sulfide (MPS) and various acid dichlorides (AC) have been studied to evaluate the effect of the thioester group in comparison with corresponding linear polyesters. Polycondensations between MPS and azelaoyl chloride (AZC) chosen as a model reaction system were investigated under various conditions by solution polycondensation, to find optimal conditions to get high molecular weight and quantitative yield. The obtained polymer using chloroform as a solvent indicated the highest molecular weight, determined by gel permeation chromatography (GPC). Thus the polythioesters from MPS and AC were synthesized under the above‐mentioned conditions. The thermal properties of polythioesters including the MPS moiety were evaluated by thermogravimetry/differential thermal analysis (TG/DTA), and differential scanning calorimetry (DSC). Those indicated that the polythioesters including the MPS moiety were crystalline polymers with relatively high heat resistance. These polythioesters were found to show an odd–even effect with the glass transition temperature, melting point, and oxygen permeability based on the methylene numbers. The tensile strength and storage modulus decreased with the number of methylene units. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 508–515, 2005     

Linear polymers with sulfur in the main chain. II. Synthesis of polyesters by interfacial polycondensation of bis(4,4′‐hydroxyphenyl)sulfide with several aliphatic acid dichlorides and their properties

The synthesis and properties of sulfur‐containing polyesters derived from bis(4,4′‐hydroxyphenyl)sulfide (TDP) and various acid dichlorides (AC) have been studied to evaluate the effect of the incorporation of sulfur in the main chains of polyesters. Polyesters derived from TDP and AC (with methylene numbers of 2–10) were synthesized by interfacial polycondensation in a 1,1,2,2‐tetrachloroethane /water mixture using tetra‐n‐butyl ammonium bromide as a phase transfer catalyst. Through the use of gel permeation chromatography, it was determined that the polyesters thus obtained had high molecular weights. The thermal properties of the polyesters including the TDP moiety were evaluated by thermogravimetry/differential thermal analysis and by differential scanning calorimetry. The analyses indicated that the polyesters including the TDP moiety were crystalline polymers with relatively high heat resistance. These polyesters were found to show an odd–even effect with the glass transition temperature and the melting point based on the methylene numbers. The tensile strength and storage modulus decreased with the methylene numbers. It was further found that the polyesters evidenced excellent barrier properties towards oxygen gas having an odd–even effect. In particular, it was shown that the polyesters with methylene numbers of 3, 4, 6, and 8 of methylene units have lower oxygen permeability than poly(ethylene terephthalate) (PET).©2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1865–1872, 2004     

Liquid crystalline and photocrosslinkable poly(4,4′‐stilbeneoxy) alkylarylphosphates

Three series of liquid crystalline and photocrosslinkable poly(4,4′‐stilbeneoxy) alkylarylphosphates were synthesized from various 4,4′‐bis(m‐hydroxyalkyloxy)stilbenes (m = 2, 4, 6, 8, 10) and arylphosphorodichloridates in chloroform by solution polycondensation method. Polarized optical microscope (POM) and differential scanning calorimetry (DSC) observations revealed that polymers containing less than four methylene spacer groups did not exhibit liquid crystalline (LC) texture, possibly due to smaller microdomain and restricted movement of the mesogen. In contrast, polymers containing more than four methylene spacer group established LC texture, which has been attributed to the larger monodomain and free movement of mesogens. Thermogravimetric analysis (TGA) data indicated that thermal stability and char yield decreased with increasing flexible methylene spacer groups, increased significantly for biphenyloxy and 1‐naphthyloxy containing polymers than that of phenyloxy containing polymers ascribed to increasing aromaticity, size, and number of aromatic rings. Photocrosslinking of stilbene containing polymers has been shown to proceed via 2π‐2π cycloaddition reaction by Ultra‐violet (UV) and fluorescence. The rate photocrosslinking has been found to increase with increasing number of methylene group in the main chain. The aromaticity of the side chain also increases the rate of crosslinking. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Synthesis and properties of poly(amide–imide)s based on N,N′‐bis(4‐carboxyphenyl)‐4,4′‐oxydiphthalimide,p‐aminobenzoic acid and various aromatic diamines

A new diimide–diacid monomer, N,N′‐bis(4‐carboxyphenyl)‐4,4′‐oxydiphthalimide (I), was prepared by azeotropic condensation of 4,4′‐oxydiphthalic anhydride (ODPA) and p‐aminobenzoic acid (p‐ABA) at a 1:2 molar ratio in a polar solvent mixed with toluene. A series of poly(amide–imide)s (PAI, III_a–m) was synthesized from the diimide–diacid I (or I′, diacid chloride of I) and various aromatic diamines by direct polycondensation (or low temperature polycondensation) using triphenyl phosphite and pyridine as condensing agents. It was found that only III_k–m having a meta‐structure at two terminals of the diamine could afford good quality, creasable films by solution‐casting; other PAIs III using diamine with para‐linkage at terminals were insoluble and crystalline; though III_g–i contained the soluble group of the diamine moieties, their solvent‐cast films were brittle. In order to improve their to solubility and film quality, copoly(amide–imide)s (Co‐PAIs) based on I and mixtures of p‐ABA and aromatic diamines were synthesized. When on equimolar of p‐ABA (m = 1) was mixed, most of Co‐PAIs IV had improved solubility and high inherent viscosities in the range 0.9–1.5 dl g^?1; however, their films were still brittle. With m = 3, series V was obtained, and all members exhibited high toughness. The solubility, film‐forming ability, crystallinity, and thermal properties of the resultant poly(amide–imide)s were investigated. © 2002 Society of Chemical Industry     

Synthesis and properties of TLCPs with 2,6‐naphthalene‐based mesogen,polymethylene spacer,and nonlinear 4,4′‐thiodiphenyl links

A series of new thermotropic main‐chain liquid crystalline copolyesters were prepared by polycondensation of 2,6‐naphthalenedicarbonyl chloride, 4,4′‐thiodiphenol, and α,ω‐alkanediols (n = 4–10) in diphenyl ether at 200°C. Thermal transition behaviors of these copolyesters were investigated by differential scanning calorimetry. Moreover, their thermal stabilities and mesomorphic textures were studied by thermogravimetric analysis and polarizing optical microscopy, respectively. Corresponding model compounds with terminal mesogenic units and central polymethylene spacers were also synthesized for comparison. Both copolymers and model compounds exhibit odd–even dependency of melting temperatures, transition enthalpy (ΔH_m), and entropy (ΔS_m) on the number of methylene units in the spacer. However, the odd–even effects in model compounds are much more distinctive. Nematic mesophases are the only texture observed in melts, except the model compounds with longer methylene units (n = 8, 10), in which smectic mesophases can be observed. The T_m values of the copolyesters (TDP/HD = 1/1) are between 233 and 259°C, depending on spacer length. The initial decomposition temperatures of the copolyesters are above 419°C under N₂ atmosphere. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1536–1546, 2002     

Single‐step solution polymerization of poly(alkylene terephthalate)s: synthesis parameters and polymer characterization

Poly(alkylene terephthalate)s represent one of the most frequently used polymer classes worldwide. Well‐known examples include poly(ethylene terephthalate) (n = 2) and poly(butylene terephthalate) (n = 4). The conventional synthesis method for these polymers is based on melt polycondensation, a two‐stage process performed under harsh conditions that includes the synthesis of an intermediate prepolymer and the presence of a catalyst, which may induce toxicity issues. The present work reports on a straightforward single‐step solution polycondensation method performed under mild conditions and in the absence of a catalyst. A homologous series of poly(alkylene terephthalate)s (n = 5 ? 10) of molar masses up to 20 000 g mol^?1 and dispersity <2.4 was synthesized and characterized thoroughly. Great attention was given to the thermal properties assessment by using state‐of‐the‐art techniques and a highly sensitive prototype technique called rapid heat ? cool DSC. Similar to melt‐synthesized polyesters, a particular odd ? even trend of the thermal properties versus the number of methylene groups within the monomer unit was revealed. To the best of our knowledge, this is the first report covering a single‐step solution‐based polycondensation performed in the absence of a catalyst that results in highly reproducible polyesters possessing unaltered thermal properties compared to polyesters synthesized through industrially applied conventional routes. © 2017 Society of Chemical Industry     

Synthesis and characterization of polyesters based on 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane

Aromatic polyesters are of considerable interest because of their excellent mechanical properties, chemical resistance and thermal stability. However, most aromatic polyesters are difficult to process due to their high glass transition temperatures coupled with their insolubility in common organic solvents. The present article describes a series of organosoluble polyesters and copolyesters based on 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane. A series of new aromatic polyesters containing pendant pentadecyl chains was synthesized by interfacial polycondensation of 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane with terephthalic acid chloride (TPC), isophthalic acid chloride (IPC) and a mixture of TPC and IPC. A series of copolyesters was synthesized from 4,4′‐isopropylidenediphenol with TPC by incorporating 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane as a comonomer. Inherent viscosities of the polyesters and copolyesters were in the range 0.72–1.65 dL g^?1 and number‐average molecular weights were in the range 18 170–87 220. The polyesters and copolyesters containing pendant pentadecyl chains dissolved readily in organic solvents such as chloroform, dichloromethane, pyridine and m‐cresol and could be cast into transparent, flexible and apparently tough films. Wide‐angle X‐ray diffraction data revealed the amorphous nature of the polyesters and copolyesters. The formation of loosely developed layered structure was observed due to the packing of pendant pentadecyl chains. The temperature at 10% weight loss, determined using thermogravimetric analysis in nitrogen atmosphere, of the polyesters and copolyesters containing pendant pentadecyl chains was in the range 400–460 °C. The polyesters and copolyesters exhibited glass transition temperatures in the range 63–82 °C and 177–183 °C, respectively. Copyright © 2010 Society of Chemical Industry     

Lipase‐catalyzed synthesis of aliphatic poly(β‐thioether ester) with various methylene group contents: thermal properties,crystallization and degradation

A series of novel aliphatic poly(β‐thioether ester)s with various methylene group contents were prepared by direct lipase‐catalyzed polycondensation of the monomer with an acid‐labile β‐thiopropionate group. The polycondensation reaction using immobilized lipase B from Candida antarctica was carried out in diphenyl ether at 90 °C. Poly(β‐thioether ester)s with high molecular weights of 20 500–57 000 Da and narrow polydispersities in the range 1.40–1.48 were obtained. Thermogravimetric analysis, differential scanning calorimetry and wide‐angle X‐ray diffraction were used to investigate the thermal properties and crystal structures of these polyesters. All the poly(β‐thioether ester)s were semicrystalline polymers and thermally stable up to at least 200 °C. In vitro degradation studies showed that they can rapidly degrade under acidic conditions by the hydrolysis of the β‐thiopropionate groups, suggesting their potential as acid‐degradable polymeric materials. © 2019 Society of Chemical Industry     

Synthesis of soluble and thermally stable polyimides from 3,5‐diamino‐N‐(4‐(8‐quinolinoxy) phenyl) aniline and various dianhydrides

Three novel polyimides (PIs) having pendent 4‐(quinolin‐8‐yloxy) aniline group were prepared by polycondensation of a new diamine with commercially available tetracarboxylic dianhydrides, such as pyromellitic dianhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride, and bicyclo[2.2.2]‐oct‐7‐ene‐2,3,5,6‐tetracarboxylic dianhydride. These PIs were characterized by FTIR, ¹H NMR, and elemental analysis; they had high yields with inherent viscosities in the range of 0.4–0.5 dl g⁻¹, and exhibited excellent solubility in many organic solvents such as N,N‐dimethyl acetamide, N,N′‐dimethyl formamide, N‐methyl pyrrolidone (NMP), dimethyl sulfoxide, and pyridine. These PIs exhibited glass transition temperatures (T_g) between 250 and 325° C. Their initial decomposition temperatures (T_i) ranged between 270 and 450°C, and 10% weight loss temperature (T₁₀) up to 500°C with 68% char yield at 600°C under nitrogen atmosphere. Transparent and hard polymer films were obtained via casting from their NMP solutions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and characterization of new optically active poly(amide‐imide)s derived from N,N‐(4,4′‐Oxydiphthaloyl)‐bis‐(s)‐(+)‐valine diacid chloride and aromatic diamines

4,4′‐Oxydiphthalic anhydride (1) was reacted with (s)‐(+)‐valine (2) in acetic acid and the resulting imide‐acid 3 was obtained in high yield. This compound 3 was converted to diacid chloride 4 by reaction with excess amount of thionyl chloride. The polycondensation reaction of diacid chloride 4 with several aromatic diamines such as 4,4′‐sulfonyldianiline (5a), 4,4′‐diaminodiphenyl methane (5b), 4,4′‐diaminodiphenylether (5c), p‐phenylenediamine (5d), m‐phenylenediamine (5e), and 4,4′‐diaminobiphenyl (5f) was performed by two conventional methods: low temperature solution polycondensation and a short period reflux conditions. To compare conventional solution polycondensation reaction methods with microwave‐assisted polycondensation, the reactions were also carried out under microwave conditions in the presence of small amount of o‐cresol that acts as a primary microwave absorber. The reaction mixture was irradiated for 4 min with 100% of radiation power. Several new optically active poly(amide‐imide)s with inherent viscosity ranging from 0.26–0.44 dL/g were obtained with high yield. All of the above polymers were fully characterized by ¹H‐NMR, FTIR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these new optically active poly (amide‐imide)s are reported. POLYM. ENG. SCI. 46:558–565, 2006. © 2006 Society of Plastics Engineers     

Effect of monomer composition on properties of copolyimides derived from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride/4,4′‐oxydianiline/1,3‐bis (4‐aminophenoxy)benzene

A series of uncontrolled molecular weight homopolyimides and copolyimides based on 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (s‐BPDA)/4,4′‐oxydianiline (4,4′‐ODA)/1,3‐bis(4‐aminophenoxy)benzene (TPER) were synthesized. All the polyimides displayed excellent thermal stability and mechanical properties, as evidenced by dynamic thermogravimetric analysis and tensile properties testing. A singular glass transition temperature (T_g) was found for each composite from either differential scanning calorimetry (DSC) or dynamic mechanical analysis (DMA), but the values determined from tan δ of DMA were much different from those determined from DSC and storage modulus (E′) of DMA. The Fox equation was used to estimate the random T_g values. Some composites exhibited re‐crystallization after quenching from the melt; upon heating, multi‐melting behavior was observed after isothermal crystallization at different temperatures. The equilibrium melting temperature was estimated using the Hoffman‐Weeks method. Additionally, DMA was conducted to obtain E′ and tan δ. Optical properties were strongly dependent on the monomer composition as evidenced by UV‐visible spectra. X‐ray diffraction was used to interpret the crystal structure. All the results indicated that composites with TPER composition ≥ 70% were dominated by the TPER/s‐BPDA polyimide phase, and ≤40% by the 4,4′‐ODA/s‐BPDA polyimide phase. When the ratio between the two diamines was close to 1:1, the properties of the copolyimides were very irregular, which means a complicated internal structure. Copyright © 2011 Society of Chemical Industry     

Highly potent and selective 4,4'‐biphenyl‐4‐acylate‐4'‐N‐n‐butylcarbamate inhibitors of Pseudomonas species lipase

4,4'‐Biphenyl‐4‐acylate‐4'‐N‐n‐butylcarbamates ( 1–8 ) are synthesized and characterized as highly potent and selective pseudo‐substrate inhibitors of Pseudomonas species lipase. Thus, the n‐butylcarbamate moieties of the inhibitors bind to the first acyl chain binding site (ACS) of the enzyme. Therefore, the ester moieties of the inhibitors may bind to the second ACS of the enzyme, due to the linear 4,4'‐biphenyl moiety of the inhibitors. –logK_i, logk₂, and logk_i values of carbamates 1–8 are multiply linearly correlated with the Taft steric constant (E_S) and the Hansch hydrophobicity constant (π), but not with the Taft substituent constant (σ*). For –logK_i, logk₂, and logk_i correlations, values of δ are 0.8, 0.34, and 1.0, respectively, and values of ψ are 1.0, 0.4, and 1.3, respectively. Positive δ and ψ values for these correlations indicate that the second ACS of the enzyme prefers to bind to small and hydrophobic ester groups of the inhibitors. Among carbamates 1–8 , carbamate 3 , with a K_i value of 2.5 nM, is the most potent inhibitor.     

Microwave‐assisted and conventional polycondensation reaction of optically active N,N′‐(4,4′‐sulphonediphthaloyl)‐bis‐L‐leucine diacid chloride with aromatic diamines

3,3′,4,4′‐Diphenylsulfonetetracarboxylic dianhydride ( 1 ) was reacted with L‐leucine ( 2 ) in acetic acid and the resulting imide‐acid ( 3 ) was obtained in high yield. The diacid chloride ( 4 ) was prepared from diacid derivative ( 3 ) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride ( 4 ) with several aromatic diamines such as 4,4′‐sulfonyldianiline ( 5a ), 4,4′‐diaminodiphenyl methane ( 5b ), 4,4′‐diaminodiphenylether ( 5c ), p‐phenylenediamine ( 5d ), m‐phenylenediamine ( 5e ), 2,4‐diaminotoluene ( 5f ), and 1,5‐diaminonaphthalene ( 5g ) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions were also performed under two conventional methods: low temperature solution polycondensation in the presence of trimethylsilyl chloride, and a short period reflux conditions. A series of optically active poly(amide‐imide)s with inherent viscosity of 0.25–0.42 dL/g were obtained with high yield. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly (amide‐imide) s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2992–3000, 2004     

Synthesis and characterization of biodegradable poly(butylene succinate‐co‐propylene succinate)s

Biodegradable polyesters such as poly(butylene succinate) (PBS), poly(propylene succinate) (PPS), and poly(butylene succinate‐co‐propylene succinate)s (PBSPSs) were synthesized respectively, from 1,4‐succinic acid with 1,4‐butanediol and 1,3‐propanediol through a two‐step process of esterification and polycondensation in this article. The composition and physical properties of both homopolyesters and copolyesters were investigated via ¹H NMR, DSC, TGA, POM, AFM, and WAXD. The copolymer composition was in good agreement with that expected from the feed composition of the reactants. The melting temperature (T_m), crystallization temperature (T_c), crystallinity (X), and thermal decomposition temperature (T_d) of these polyesters decreased gradually as the content of propylene succinate unit increased. PBSPS copolyesters showed the same crystal structure as the PBS homopolyester. Besides the normal extinction crosses under the polarizing optical microscope, the double‐banded extinction patterns with periodic distance along the radial direction were also observed in the spherulites of PBS and PBSPS. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

How the monomer concentration of polymerization influences various properties of polybenzimidazole: A case study with poly(4,4′‐diphenylether‐5,5′‐bibenzimidazole)

In this work, a series of poly(4,4′‐diphenylether‐5,5′‐bibenzimidazole)s (OPBIs) were synthesized from 4,4′‐oxybis(benzoic acid) and 3,3′,4,4′‐tetraaminobiphenyl through the variation of the initial monomer concentration with a solution polycondensation technique in a poly(phosphoric acid) medium. The resulting polymers were characterized by various techniques such as infrared (IR), nuclear magnetic resonance, dynamic mechanical analysis (DMA), and thermogravimetric analysis. The initial monomer concentration in the polymerization mixture played an important role in controlling the molecular weight of the resulting polymers. A temperature‐dependent IR study showed that the free movement of the ? NH group of the imidazole ring was blocked by the absorbed moisture. The DMA study showed that the glass‐transition temperature (T_g) varied with the molecular weight, and the presence of the ether linkage in the OPBI polymer backbone had a significant influence on T_g. A high‐molecular‐weight OPBI polymer tended to form a supramolecular organization, which influenced the thermal characteristic of the polymer. Photophysical studies demonstrated the fluorescent characteristics of the OPBI polymers in both solid and solution states. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Modification of bismaleimide resin by poly(ethylene phthalate‐co‐ethylene terephthalate), poly(ethylene phthalate‐co‐ethylene 4,4′‐biphenyl dicarboxylate), and poly(ethylene phthalate‐co‐ethylene 2,6‐naphthalene dicarboxylate)

Aromatic polyesters were prepared and used to improve the brittleness of bismaleimide resin, composed of 4,4′‐bismaleimidodiphenyl methane and o,o′‐diallyl bisphenol A (Matrimid 5292 A/B resin). The aromatic polyesters included PEPT [poly(ethylene phthalate‐co‐ethylene terephthalate)], with 50 mol % of terephthalate, PEPB [poly(ethylene phthalate‐co‐ethylene 4,4′‐biphenyl dicarboxylate)], with 50 mol % of 4,4′‐biphenyl dicarboxylate, and PEPN [poly(ethylene phthalate‐co‐ethylene 2,6‐naphthalene dicarboxylate)], with 50 mol % 2,6‐naphthalene dicarboxylate unit. The polyesters were effective modifiers for improving the brittleness of the bismaleimide resin. For example, inclusion of 15 wt % PEPT (MW = 9300) led to a 75% increase in fracture toughness, with retention in flexural properties and a slight loss of the glass‐transition temperature, compared with the mechanical and thermal properties of the unmodified cured bismaleimide resin. Microstructures of the modified resins were examined by scanning electron microscopy and dynamic viscoelastic analysis. The toughening mechanism was assessed as it related to the morphological and dynamic viscoelastic behaviors of the modified bismaleimide resin system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2352–2367, 2001     

Synthesis and electrical properties of copolymers of o‐phenylenediamine with aniline, 3,4‐ethylenedioxythiophene and 2,3,5,6‐tetrafluoroaniline

Copolymers (P(PDA/Ar)) of o‐phenylenediamine with aniline (Ar = ANi), 3,4‐ethylenedioxythiophene (Ar = EDOT) and 2,3,5,6‐tetrafluoroaniline (Ar = TFANi) were synthesized via polycondensation initiated by ammonium persulfate. The NH₂ group content in the copolymers was determined by analyzing the ¹H NMR spectra of the N‐acetylated copolymers. Copolymers crosslinked by viologen (1,1'‐disubstituted 4,4'‐bipyridinium dichloride) were obtained by reaction involving the reactive NH₂ groups in the copolymers. The absorption wavelengths of solutions of the copolymers and the electrochemical oxidation and reduction potentials of cast films of the copolymers were affected by the electrical properties of the Ar unit. © 2016 Society of Chemical Industry     

Synthesis and characterization of aromatic polyesters and copolyesters from 4,4′‐(1‐hydroxyphenylidene)diphenol and 4,4′‐(9‐fluorenylidene)diphenol

Two isophthalic polyesters from 4,4′‐(1‐hydroxyphenylidene)diphenol (BAP/ISO) and 4,4′‐(9‐fluorenylidene)diphenol (BF/ISO), and three different copolyesters containing 75, 50, and 25 mol % of BAP/ISO were synthesized by interfacial polycondensation. This preparation method yielded polymers and copolymers that produced flexible and transparent films when they were cast from solution. Proton NMR spectrometry studies showed that the isophthalic copolyesters were obtained as random copolymers with differences in comonomer composition no larger than 2.5 mol % with respect to the expected compositions. Wide‐angle X‐ray diffraction measurements indicated that all the polyesters and copolyesters were amorphous. The copolyesters showed amorphous patterns with maxima that fell between those of the polyesters. It was also found that thermal properties such as glass‐transition temperature, onset of decomposition temperature, thermal stability, dynamic mechanical storage modulus, and maximum on the α‐transition of the damping factor tan δ of BF/ISO were higher than those of BAP/ISO. The values of these thermal properties in the copolyesters fell between those of the polyesters and were dependent on the amounts of BF/ISO and BAP/ISO present in the copolyester in a linear fashion. Therefore, the thermal properties of a given copolyester can be predicted directly from the comonomers' composition. Overall, it shows that the interfacial polycondensation method is suitable to obtain these copolyesters in a controlled manner and that their properties can be tailored to be between those of the homopolyesters. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2515–2522, 2002     

Novel optically active poly(amide‐imide)s with tetrahydropyrimidinone and tetrahydro‐2‐thioxopyrimidine moieties by microwave‐assisted polycondensation

Rapid and highly efficient synthesis of novel poly(amide‐imide)s (PAIs) were achieved under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of 4,4′‐carbonyl‐bis(phthaloyl‐L ‐alanine) diacid chloride [N,N′‐(4,4′‐carbonyldiphthaloyl)] bisalanine diacid chloride (1) with six different derivatives of tetrahydropyrimidinone and tetrahydro‐2‐thioxopyrimidine compounds (2a–2f) in the presence of a small amount of a nonpolar organic medium that acts as a primary microwave absorber. Suitable organic media was o‐cresol. The polycondensation proceeded rapidly and was almost completed within 10 min, giving a series of PAIs with inherent viscosities of about 0.25–0.45 dL/g. The resulting PAIs were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by means of Fourier transform infrared spectroscopy, elemental analyses, inherent viscosity (η_inh), solubility test, and specific rotation. Thermal properties of the PAIs were investigated using thermogravimetric analysis. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2416–2421, 2001     

Synthesis,characterization, and antimicrobial properties of oligo‐4‐[(pyridine‐3‐yl‐methylene) amino] phenol

The oxidative polycondensation reaction conditions of 4‐[(pyridine‐3‐yl‐methylene) amino]phenol (4‐PMAP) were studied using H₂O₂, atmospheric O₂, and NaOCl oxidants in an aqueous alkaline medium between 30°C and 90°C. Synthesized oligo‐4‐[(pyridine‐3‐yl‐methylene) amino] phenol (O‐4‐PMAP) was characterized by ¹H‐, ¹³C NMR, FTIR, UV–vis, size exclusion chromatography (SEC), and elemental analysis techniques. The yield of O‐4‐PMAP was found to be 32% (for H₂O₂ oxidant), 68% (for atmospheric O₂ oxidant), and 82% (for NaOCl oxidant). According to the SEC analysis, the number–average molecular weight, weight–average molecular weight, and polydispersity index values of O‐4‐PMAP was found to be 5767, 6646 g mol^?1, and 1.152, respectively, using H₂O₂, and 4540, 5139 g mol^?1, and 1.132, respectively, using atmospheric O₂, and 9037, 9235 g mol^?1, and 1.022, using NaOCl, respectively. According to TG and DSC analyses, O‐4‐PMAP was more stable than 4‐PMAP against thermal decomposition. The weight loss of O‐4‐PMAP was found to be 94.80% at 1000°C. Also, antimicrobial activities of the oligomer were tested against B. cereus, L. monocytogenes, B. megaterium, B. subtilis, E. coli, Str. thermophilus, M. smegmatis, B. brevis, E. aeroginesa, P. vulgaris, M. luteus, S. aureus, and B. jeoreseens. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3327–3333, 2006