SYNTHESIS OF AN EPOXY-TERMINATED HYPERBRANCHED AROMATIC POLYESTER

An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromatic polyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of the AB(2) monomer, 5-acetoxyisophthalic acid. Polymer P1 was converted into the polymeric acid chloride by reaction with thionyl chloride. The acid chloride was reacted with ethanol and glycidol to form a poly(ethyl ester) (P2) and an epoxy terminated material (P3), respectively. The reaction conditions in each step of these processes had to be controlled very carefully to avoid unwanted cross-linking reactions. The characterization of products and intermediates, including molecular weight distributions and thermal properties, are reported.

Synthesis and characterization of new polyesters based on 2,5-bis[(4-chloro carboxyanilino)carbonyl]pyridine and aromatic diols

Six new polyesters 7a-f were synthesized through the solution polycondensation reaction of diacid chloride 5 with six aromatic diols 6a-f in N,N-dimethyl acetamide(DMAc) as solvent in the presence of pyridine as base.The polycondensation reaction produced a series of novel polyester containing pyridyl moiety in the main chain in high yields with inherent viscosities between 0.35 and 0.54 dL/g.The resulted polymers were fully characterized by means of FT-IR spectroscopy,elemental analyses,inherent viscosity ...

SYNTHESIS AND CHARACTERIZATION OF MAIN CHAIN AROMATIC LIQUID CRYSTAL COPOLYESTERS WITH X-SHAPED AND ROD-SHAPED MESOGENIC UNITS

A series of main chain liquid crystal aromatic copolyesters with X-shaped and rod-shaped mesogenic units were synthesized via solution condensation polymerizations of 4,4'-(alpha,omega-octanedioyloxy)-dibenzoyl dichlorides with 2,5-bis(p-octanoxy benzoyloxy)-hydroquinone and diphenol. All of the copolyesters showed thermotropic liquid crystalline behaviors through observations using DSC, polarized microscopy and X-ray diffraction. The melting point (T-m) and the isotropization temperature (T-i) change regularly with varying the content of diphenol unit in the copolymers.

Novel dihydropyrazole derivatives linked with multi(hetero)aromatic ring:Synthesis and antibacterial activity

Eight novel heterocycle-substituted dihydropyrazole derivatives were synthesized and characterized by ESI-MS, ^1H NMR and ^13C NMR. All of the compounds have been screened for their antibacterial potential in vitro against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The results show that compounds 9b, 9g and 9h displayed significant activity with MIC values in the range of 0.39-1.562 μlmL against B. subtilis.

Synthesis of Methyl-substituted Phthalazinone-based Aromatic Poly(amide imide)s

A series of novel aromatic poly ( amide imide)s containing phthalazinone moieties were prepared from 2-(4-aminophenyl)-4-[3-methyl-4-(4-aminophenoxy)-2,3-phthalazinone-1], a novel diamine 1 with four diimide-dicarboxylic acids by Yamazaki phosphorylation method with the inherent viscosity of 0.36~0.65 dL/g. These polymers had high glass transition temperatures above 300C and they lost 10% weight between 426~475C in N2. The structure of diamine 1 and the polymers was confirmed by IR, 1H NMR and MS. The obtained polymers were readily soluble in polar solvents such as NMP, m-cresol etc. and easily cast into tough, flexible films. The X-ray indicated that they are all amorphous.

Synthesis and Evaluation of Aromatic DTPA-bis(amide)Gadolinium Complexes as Magnetic Resonance Imaging Contrast Agents

Five DTPA bis(amide)s have been synthesized and characterized by means of 1 H NMR , FT IR and elemental analyses. The stability constants of their Gd 3+ complexes have been measured using a simple spectrophotometric method. The results show that the complexing properties of the ligands in comparison with those of DTPA are affected by converting two carboxyl groups to amide groups. The relaxation studies have shown that the relaxivity of the chelates is similar to that of Gd DTPA, indicating that in solution all the chelates have one water molecule directly coordinated to the metal ion. Only one water molecule in inner coordination sphere suggests the coordination of the carboxamide oxygen to gadolinium ion, which agrees with the FT IR results.

STUDY ON THE SYNTHESIS AND PHYSICOCHEMICAL PROPERTIES OF SUCROSE POLYESTER

Orthogonal test was used to evaluate the effects of synthetic such as temperature （120-140 ℃）, reaction time （4-6） and substrate molar ratio of methyl oleate to sucrose （8：1-12：1） on the percent quantity conversion to sucrose polyester. Sucrose polyester was synthesized by a solvent-free one-stage interesterification. The optimum reaction conditions are as follows： methyl oleate/sucrose =10： 1 （mol/mol）; reaction temperature is 140 ℃; reaction time is 5 hours. The product yield reaches 88.15%, and the degree of esterification （DE） is over 7 in the conditions. Thin layer chromatography （TLC）, column chromatography （CC）, High-performance liquid chromatography （HPLC） were used to analyze the product, the results show that the percent of sucrose polyoleate is over 70% in the product. The physicochemical properties of sucrose polyesters were compared with cooking oil. The results show that the qualities of sucrose polyesters are all up to the triglyceride.

Synthesis and characterization on semi-aromatic polyamide containing benzoxazole unit

In order to obtain a novel polyamide having excellent heat-resistant properties which could be anticipated as a thermal modifier for aliphatic polyamide,a series of new semi-aromatic polyamides (BO6,BO8,BO10) containing benzoxazole unit were synthesized based on 5-amino-2-(p-aminophenyl) benzoxazole (ABO) and aliphatic acids (adipic,suberic and sebacic acid) by means of Yamazaki phosphorylation method.The effect of reaction temperature on the inherent viscosity of the polymers was studied,and the structures of products were characterized by FTIR,1 H-NMR,and the heat resistance of the polymers was studied by DSC and TG.The results showed that the reaction temperature gives the polymers the highest viscosity at around 90 ℃,130 ℃ and 130 ℃ for BO6,BO8 and BO10,respectively.The heat resistance of the new semi-aromatic polyamides is much higher than that of the common aliphatic polyamides.In addition,the products show good solvent resistance and crystallization properties.

Synthesis of aromatic-linked polyamine macrocyclic derivatives as HIV-1 entry inhibitors

A series of novel aromatic-linked polyamine macrocyclic derivatives have been synthesized. Their structures were confirmed by MS and ^1H NMR. These compounds exhibited potent anti-HIV-1 activities.

MORPHOLOGY OF A THERMOTROPIC AROMATIC POLYESTER

The crystalline morphology of a thermotropic aromatic polyester has been studied by microscopy techniques. Spherulites with ringed structure under polarizing micioscope were observed for solution cast specimens, They were composed of radially growing crystalline lamellae of thickness around 100. It was found that the molecules were packed in the thickness direction. Banded texture was observed in randomly packed domains for melt cast specimens. The bands have the same width and internal structure as those usually observed in oriented specimens of these polymers obtained by shearing their mesomorphic melt.

FOURIER TRANSFORM INFRARED STUDY OF FRACTIONATED AROMATIC POLYESTERS

Infrared spectra at different temperatures have been studied for fractions ofa liquid crystal tormmg aromatic polyester. The molecular interactions in different phases and their changes duringthe transitions were discussed. Abrupt frequency shift was found for bands of groups both in mesogens and flexible spacers during fusion and isotropization transitions. It may imply that both the mesogens and the flexible spacers are included in the same crystalline phase and give their contributions to the formation of the mesophase. The splitting into doublet of the C—O stretching vibrations was observed for both the aromatic and aliphatic esters and was attributed to the existence of local regions for ester groups different in ordering. The more ordered regions do not disappear completely even in the isotropic liquid phase.

THE GAS TRANSPORT BEHAVIOR IN AROMATIC POLYESTER MEMBRANES

Six aromatic polyesters were prepared for gas separation membranes, and their permeation properties for hydrogen, oxygen, nitrogen, carbon dioxide, and methane were measured at 30 degrees C and 1 atmosphere by low pressure manometric method. The correlation between the gas transport behavior and molecular structure of aromatic polyester membrane is discussed. These data are interpreted qualitatively in terms of the calculated packing density, gas-polymer interaction, concentration of aryl bromine on backbone, and effect of silane group on main chain of polymer.

THE EFFECT OF SUBSTITUENT ON THE THERMAL PROPERTIES OF POLYESTERS CONSISTING OF AROMATIC TYPE SCHIFF BASE MESOGENIC UNITS AND POLYMETHYLENE SPACERS

Polyesters consisting of substituted aromatic type Schiff base mesogenic unit andpolymethylene spacers were synthesized and their thermal transitions and liquid crystallineproperties were studied. The liquid crystalline behaviour has been characterized by differentialscanning calorimetry (DSC) and optical polarizing microscopy. Structural broadening bysubstitution of methoxy group in 2, 2' positions of the mesogenic core produce polymers withlower transition temperatures. Polymers synthesized from ortho and meta substituted phenylenediamine did not form a liquid crystal phase.

Synthesis of a New Aromatic Dianhydride Containing Pyridine Ring and Related Polyimide

A new aromatic dianhydride monomer containing pyridine moiety, 2,6-bis[4＇-（3＂,4＂- dicarboxyphenoxy）benzoyl]-pyridine dianhydride （Md）, was synthesized in four steps, starting from 2,6-pyridinedicarboxyl chloride. A novel pyridine-containing polyimide was prepared via polycondensation of Md with ODA by two-step method. The resulting polyimide exhibits excellent solubility, film-forming capability and high thermal resistance.

SYNTHESIS AND CHARACTERIZATION OF LIQUID CRYSTAL POLYESTERS WITH T-SHAPED TWO-DIMENSIONAL MESOGENIC UNITS(Ⅲ)

A new series of liquid crystal polyesters with T-shaped two-dimensional mesogenic units weresynthesized by melt polycondensation of the diacetates of 2-(4'-alkoxy -phenyl)-hydroquinones with 4,4'-alkylenedioxydibenzoic acid. The polymers were characterized by using polarized microscopy, DSC and X-ray diffraction. It was realized that all the polymers have nematic thermotropic liquid crystallinecharacteristics. The melting temperature (T_m) and isotropization temperature (T_i) of the polymers changeregularly with varying lengths of the alkoxy side group and the length of the alkylene group in the main chainin company with an even-odd effect. The mesophase temperature range also varies regularly with the polymerstructure. It is shown that the mesophase range has been widened.

Study on Structure and Crystallinity of A New Biodegradable Aliphatic-Aromatic Copolyester

A series of biodegradable aliphatic-aromatic copolyesters, poly(butylene terephthalate-co-butylene adipate-co- ethylene terephthalate-co-ethylene adipate) (PBATE), were synthesized from terephthalic acid (PTA), adipic acid (AA), 1,4-butanediol (BG) and ethylene glycol (EG) through direct esterification and polycondensation. The sequence structure and crystallinity of the copolyester were investigated by 1H NMR spectroscopy and the wide-angle X-ray diffractometry (WAXD). The analytical results showed that the PBATE copolyester was a random copolymer and the composition of PBATE copolyester was almost consistent with the feed molar ratios. The crystal structure of PBATE copolyester belonged to the triclinic crystalline system; The variation in melting point of the synthesized PBATE copolyester agreed well with the estimation obtained by the Flory equation and was applicable to the random copolymer.

CRYSTALLINE MORPHOLOGY IN A SERIES OF CH_(3)-SUBSTITUTED THERMOTROPIC AROMATIC POLYESTERS WITH EVEN AND ODD FLEXIBLE SPACERS

Crystalline morphology in a series of CH_(3)-substituted main chain thermotropic aromatic polyesters with even and odd numbered methylene spacers has been studied by polarizing optical microscopy(POM),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).On crystallization from solution evaporation spherulites of radial structure were observed in the polymers with even numbered spacers,but spherulites with concentric rings form in the polymer with odd numbered spacers.Both spherulites have a lamellar structure,which is about 10 nm in thickness.On crystallization from nematic glassy state spherulites can not be grown;lamellar structure was only observed around disclinations in a specimen during crystallization.Ln the case of crystallization from nematic melt two types of spherulites can be observed far the sample with even numbered spacers.For the sample with add numbered spacers spherulites can not be formed,but only irregular crystallites.

SYNTHESIS OF POLYSUBSTITUTED AROMATIC COMPOUNDS:Ⅰ.THE DIELS-ALDER REACTION OF SELENO SUBSTITUTED 3-SULFOLENES WITH DIMETHYL ACETYLENEDICARBOXYLATE

The seleno substituted aromatic compounds were prepared via the Diels-Alder reaction of seleno substituted 3-sulfolenes with dimethyl acetylenedicarboxylate followed by DDQ dehydrogenation.

SYNTHESIS OF FUNCTIONAL UNSATURATED POLYESTER BY USING RARE EARTH CATALYSTS 2.TERPOLYMERIZATION OF EPICHLOROHYDRINMALEIC ANHYDRIDE-CARBON DIOXIDE WITH Y(P_(204))_3-Al(i-Bu)_3

Teroolymerization of enichlorohydrin（ECH）-maleic anhydride（MAn）-carbon dioxide（CO;） was carried out by using Y(P;);-Al（i-Bu）;as catalyst for the first time.The terpolymersobtained were characterized by IR and;H-NMR.It was foundthat the composition of the teroolymer was influenced by theaddition mode,initial monomer charge ratio,etc.

A NEW METHOD FOR SYNTHESIS OF O-ISOPROPYL SUBSTITUTED AROMATIC COMPOUNDS

Heteroatom-directed aromatic lithiation reactions used for the regiospecific synthesis of o-isopropyl substituted phenolic and benzyl alcoholic compounds are described.