PREPARATION OF LIQUID CRYSTALLINE COPOLYESTERS WITH SPACERS BASED ON BISPHENOL-A,BISPHENOL-S OR POLYSULFONE BY DIRECT POLYCONDENSATION

Four series of copolyesters were synthesized by direct polycondonsation reaction between aromatic dicarboxylic acids and bisphenols by using tosyi chloride and N, N-dimethylformamide ( DMF ) in pyridine under mild conditions. The electron-rich hydroxyl groups of bisphenols favoured the polycondensation reaction and the order of relative reactivities of bisphenols is as follow:bisphenoI-A> hydroquinone ～ bisphenol-S> chlorohydroquinone. The mesomorphic properties of copolyesters were examined by birefringence under polarizing microscope, melt transparency. DSC and X-ray diffraction. The minimum molar fraction of mesogenic units needed for the appearance of liquid crystallinity is not higher than 0. 1 despite of the different varieties and lengths of the spacers studied.

Synthesis and Characterization of Cross-linked Poly (β-Cyclodextin) Graft Poly(lactic acid) through Direct Polycondensation

1 Results Polylactide or polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA) have been utilized as bioabsorbable materials in the medical and pharmaceutical fields due to their biodegradable and biocompatible properties[1].However,due to its hydrophobicity and free carboxylic group,PLA or PLGA was not suitable for use to encapsulate the protein.Recently,poly (ε-caprolactone) and poly (D,L-lactide) were respectively grafted onto hydrophilic dextrin and gelatin to obtain the amphiphilic biodeg...

Direct Arylation Polycondensation of Thiophene-Based C−H Monomers

Direct arylation polycondensation(DArP)has emerged as an eco-friendly and atom-efficient methodology for the syntheses ofπ-conjugated polymers(CPs).This approach features the direct C—H arylation of an aromatic hydrocarbon with an aryl halide.Given the prevalence of thiophene-containing CPs,achieving efficient and defect-free DArP of thiophene-based C−H monomers is of great significance.This review presents a mechanistic insight into DArP and describes the development of DArP catalytic systems for varied thiophene-based C−H monomers.Moreover,the control of the primary defects(i.e.,branching and homo-coupling)in thiophene-based DArP is also elaborated.By emphasizing the principles behind monomer selection and catalytic system optimization,this review intends to provide a framework for future advancements in the DArP of thiophene-containing CPs.

3-Methylcyclohexanone Processed n-Channel Organic Thin-Film Transistors Based on a Conjugated Polymer Synthesized by Direct Arylation Polycondensation

The solubility of a direct arylation polycondensation(DArP)synthesized conjugated polymer,i.e.,poly(3,6-bis(furan-2-yl)-2,5-bis(4-tetradecyloctadecyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-1,2-bis(3,4-d ifl uorothien-2-yl)ethene)(PFuD PP-4FTVT),in variou s organic solvents was studied.The polymer is soluble in 3-methylcyclohexanone(3-MC),a green solvent from peppermint oil,besides other solvents such as anisole,cyclopentyl methyl ether(CPME)and o-dichlorobenzene(o-DCB),etc.Based on the Hansen solu bility parameters(HSP)analysis,3-MC is identified as a"marginal solvent"of PFuDPP-4FTVT.The morphology of the spin-coated films with 3-MC as the solvent strongly correlated with the solution preparation conditions.With a 3-MC solution aged for 3 h at 70℃,n-channel organic thin-film transistors(OTFTs)with electron mobility(μe)above 1 cm^(2)·V^(-1)·s^(-1) and current on/off ratio(Ion/Ioff)higher than 105 were fabricated by spin-coating.This is the first report on high mobility conjugated polymers for OTFTs processible with natu rally occurred green solvent.

New optically active poly(amide-imide)s derived from N,N'-(4,4-diphthaloyl)-bis-L-leucine and hydantoin derivatives:Synthesis and properties

Six new optically active poly（amide-imide）s （5a-f） were synthesized through the direct polycondensation reaction of N,N′-（4,4′- diphthaloyl）-bis-L-leucine （3） with six hydantoin derivatives （4a-f）. Tripbenyl phosphite （TPP）/pyridine in the presence of calcium chloride （CaCl2） and N-methyl-2-pyrrolidone （NMP） were successfully applied for direct polycondensation. The polycondensation reactions produce a series of new poly（amide-imide）s （5a-f） in high yields, and inherent viscosity between 0.42 and 0,55 dL/g. The resulting poly（amide-imide）s （5a-f） were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis （TGA and DTG）, solubility test and FT-IR spectroscopy.

Synthesis and characterization of new optically active copoly(amid-imide)s based on N-phthalimido-L-aspartic acid and aromatic diamines

In this article,six new optically active copoly(amide-imide)s(10a-f) were synthesized through the direct polycondensation reaction of N-phthalimido-L-aspartic acid(4) with 1,5-diamino naphthalene(8),3,4-diamino benzophenone(9) in the presence of therphthahc acid(7),fumaric acid(6) and adipic acid(5) as a second diacid in a medium consisting of N-methyl-2-pyrrolidone,triphenyl phosphite, calcium chloride and pyridine.The resulting copolymers were fully characterized by means of FT-IR spectroscopy,elemental a...

Synthesis and Characterization of Poly(ether amide)s Containing Phthalazinone Moieties

Soluble aromatic polyamides containing phthalazinone moieties were prepared. Those polymers were obtained from the solution polymerization of a new diacid containing phthalazinone moieties with various diamines. The new monomer, 2-(4-carboxyphenyl)-4-(4- carboxyphenoxy ) phenyl-1 (2H) phthalazinone (Ⅳ) was synthesized in a two-step reaction sequence. 2- (4-Cyanophenyl)-4-(4-cyanophenoxy)phenyl-1 (2H)phthalazinone (Ⅲ) was prepared via the condensation reaction of 4-(4-hydroxyphenyl )-1 (2H) phthalazinone (I) with p-chlorobenzonitrile (Ⅱ). After (Ⅲ) was hydrolyzed, (Ⅳ) was acquired. The synthesized polyamides were characterized by means of viscosimetry, DSC, FT-IR, ~1H NMR and EA. The polyamides have a high glass transition temperature which can be as high as 316 C. The polyamides also have good solubilities in some organic solvents.

Substituent Effects on Direct Arylation Polycondensation and Optical Properties of Alternating Fluorene-Thiophene Copolymers

Four thiophene derivatives were prepared by replacing the 3,4 positions of thiophene by―OCH3, ―CH3―COOCH3 and ―CN, respectively. The polycondensations via direct arylation took place between the four thiophene derivatives and 2,7-dibromo-9,9-dioctylfluorene under six various catalytic conditions to investigate the substituent effects. The substituent can affect the electron cloud density of the active C―H bond, which can be monitored by the NMR chemical shift. The experimental results show that the reactivity decreases with increasing the chemical shift of active C―H bonds in the four thiophene derivatives, and thus can promote the direct arylation polycondensation. This phenomenon is explained by the electrophilic aromatic substitution（SEAr） mechanism. UV-Visible absorption and photoluminescence were studied to investigate the substituent effect on optical properties of the four copolymers. The results show that these alternating fluorene-thiophene copolymers with different substituents are good fluorescent materials and promising in PLED applications.

BIODEGRADABLE ALIPHATIC/AROMATIC COPOLYESTERS BASED ON TEREPHTHALIC ACID AND POLY(L-LACTIC ACID):SYNTHESIS,CHARACTERIZATION AND HYDROLYTIC DEGRADATION

Biodegradable aliphatic/aromatic copolyesters, poly（butylene terephthalate-co-lactate） （PBTL） were prepared via direct melt polycondensation of terephthalic acid （TPA）, 1,4-butanediol （BDO） and poly（L-lactic acid） oligomer （OLLA）. The effects of polymerization time and temperature, as well as aliphatic/aromatic moiety ratio on the physical and thermal properties were investigated. The largest molecular weight of the copolyesters was up to 64100 with molecular weight distribution index of 2.09 when the polycondensation was carried out at 230℃ for 6 h. DSC, XRD, DMA and TGA analysis clearly indicated that the degree of crystallinity, glass-transition temperature, melting point, decomposition temperature, tensile strength, elongation and Young＇s modulus were influenced by the ratio between TPA and OLLA in the final copolyesters. Hydrolytic degradation results demonstrated that the incorporation of biodegradable lactate moieties into the aromatic polyester could efficiently improve hydrolytic degradability of the copolymer even though it still had many aromatic units in the main chains.

SYNTHESIS AND CHARACTERIZATION OF POLYAMIDES DERIVED FROM(4-(4-(2,6-DIPHENYLPYRIDIN-4YL)PHENOXY)PHENYL)-3,5-DIAMINOBEZAMIDE

New types of polyamides containing pendent triaryl pyridine groups were successfully synthesized by direct polycondensation of a symmetry diamine,（4-（4-（2,6-diphenylpyridin-4yl）phenoxy）phenyl）-3,5-diaminobezamide（DPDAB）, and various aromatic and aliphatic dicarboxylic diacids in NMP using triphenyl phosphate（TPP） and pyridine as catalyst. The diamine and all the prepared polyamides were fully characterized by using FT-IR,~1H-NMR,UV-Vis spectroscopy, fluorimetry and elemental analysis.The inherent viscosity of polyamides ranged from 0.45 dL/g to 0.68 dL/g.All the polymers exhibited solubility in common polar aprotic solvents such as NMP,DMAc,DMF,DMSO,pyridine,HMPA,and even in less polar solvents such as THF and m-cresol at room temperature.Thermal properties of polyamides were evaluated by means of DSC,DMTA and TGA.These polymers showed glass transition temperatures（T_g） in the range of 138-210℃. Their initial decomposition temperature（T_i） varied from 265℃to 310℃under N_2.The dilute solution（0.2 g/dL） of polyamides in DMF exhibited fluorescence emission withλ_（max） in the range of 470-550 nm.