含苯并硒二唑组分的聚对苯撑乙炔类共轭聚合物的合成及性能研究

通过钯催化的Sonagashira偶合反应合成出了3种带有不同链长烷氧基侧链,主链中含有2,1,3-苯并硒二唑纽分的聚苯乙炔类共轭聚合物并对其化学结构进行了表征确认.此类聚合物在常用的有机溶剂中具有较好的溶解性和成膜性.通过紫外可见光谱、荧光光谱、循环伏安等对所得聚合物的基本性能进行了探讨.聚合物P7、P9和P12在溶液状态下的紫外吸收分别为421、450和450nm,相对应最大发射分别位于475、482和481nm;固态下聚合物的吸收分别为433、486和486nm,相对应最大发射为575、583和590nm.聚合物的循环伏安测试表明聚合物P7、P9、P12的起始电位为1.19、1.19、1.18V.聚合物非线性光学性能研究表明取代基为十二碳烷氧基的聚合物显示出了良好的三阶非线性光学性能,其三阶非线性光学系数为3.54×10-12esu.     

新型高度支化聚氨酯-酰亚胺的合成与表征

以季戊四醇(PAT)、甲苯-2,4-二异氰酸酯(TDI)、异佛尔酮二异氰酸酯(IPDI)以及均苯四甲酸二酐(PM-DA)通过两步法制得了两种新型具有高度支化结构的聚氨酯-酰亚胺(PUITPP和PUIIPP)。研究发现:PUITPP在40℃时预聚反应的时间为40min,酰亚胺化反应在120℃反应2h后完成。高度支化PUITPP和PUIIPP均为晶相分明的半结晶态,分子链间距(d)分别为0.3896nm和0.4089nm。这两种嵌段共聚物分别在228.5℃和215.8℃附近出现两个玻璃化转变,它们在N2中呈现出两个失重台阶,对应的热分解温度(Td)分别在230℃和630℃,玻璃化温度则分别为220℃和325℃。另外它们能溶于少数几种强极性非质子有机溶剂,且对无机稀酸具有一定的抗腐蚀性。     

Synthesis and characterization of a novel versatile poly(amic acid) derived from ethylenediaminetetraacetic dianhydride

The polycondensation reaction between ethylenediaminetetraacetic dianhydride and 1,4-diaminobutane in various aprotic polar solvents is being exploited to create a novel linear aliphatic polymer poly(amic acid) (PAA). PAA samples were characterized by Fourier transform infrared, Proton nuclear magnetic resonance and Carbon nuclear magnetic resonance spectroscopy resulting in the identification of characteristic absorption bands and thereby verifying successful synthesis. Gel permeation chromatography confirmed narrow molecular weight distributions with polydispersity indices ranging from 1.2 to 2.2 and reported low number average molecular weights ranging from 4000 to 6000 g mol⁻¹. X-ray photoelectron spectroscopy and energy dispersive X-ray analysis showed the presence of nitrogen on the surface and also found nitrogen to be homogenously distributed throughout the bulk of the PAA samples.     

含二噻基哒嗪的聚芳炔类衍生物的合成与性能研究

以四(三苯基磷)钯(Pd(PPh3)4)和CuI作为催化剂,在二异丙胺和四氢呋喃溶液中,采用宽能带的1,4-二乙炔基-2,5-二(十二烷氧基)苯(PE)和窄能带的3,6-双(5′-溴-2′-噻吩)-哒嗪(TPD)以不同配料比合成了一系列新型聚芳炔。长链烷氧基的存在使得此类聚合物在常用的有机溶剂中具有较好的溶解性和成膜性。通过对上述聚合物的紫外-可见吸收、荧光发射及循环伏安等基本性能进行探讨可知,共聚物在THF溶液中的荧光量子效率为51%～61%;随着共聚物中TPD含量的增加,共聚物薄膜的吸收起始波长及荧光发射波长均有红移。聚合物薄膜的最大发射峰位于540～551nm。     

含3-氨基(N-氨基酞酰亚胺)的新型聚酰亚胺合成与表征

合成了一种不对称舍肼二胺单体3-氨基(N-氨基酞酰亚胺),通过1H NMR、IR确认了其结构,并用15N NMR证实了该化合物两种氨基活性存在差异.采用传统的一步法用对氯苯酚做溶剂,用该二胺单体与三酐4,4'-BPDA,4,4'-ODPA 4,4'-BTDA,4,4'-HQDPA和BPADA聚合得到一系列新型聚合物,并进行了表征.其中由4,4'-HQDPA和BPADA聚合得到的聚酰亚胺薄膜,有较好的机械性能.     

Synthesis and characterization of some novel thermally stable poly(amide–imide)s

Two new diamines with built-in amide linkage were synthesized from p-nitrobenzoyl chloride in two steps and characterized by their melting points, elemental analyses, FT-IR and ¹H–NMR spectral studies. One of the diamine precursors was also characterized by single crystal X-ray analysis indicating the trans orientation of amide bonds. The planes of the aromatic rings formed dihedral angles in the range of 11.7°–56.2° and the crystal packing was stabilized by N–H···O hydrogen bonds. The synthesized diamines were then polymerized with three commercially available dianhydrides either by one-step solution technique or by two-step procedure involving ring-opening poly-addition to give polyamic acid followed by cyclic dehydration. The resulting poly(amide–imide)s were characterized by their elemental analyses and FTIR spectroscopy. The polymers possessed excellent chemical resistance and were found insoluble in almost all the common solvents tested except conc. H₂SO₄, in which these showed inherent viscosities in the range 0.47–0.73 dL g⁻¹ at 28 °C. The thermal behavior of the polymers, investigated by the DSC and TG analyses, revealed that the products were stable up to 300 °C in nitrogen. The activation energies of pyrolysis, entropy, and enthalpy values for each of the synthesized polymers were also estimated by Horowitz and Metzger method using thermal degradation data. These values were high exhibiting the remarkable thermal stability of the poly(amide–imide)s. Wide-angle X-ray studies of the polymers were also carried out which provided information about their morphology.     

Electrospinning of novel biodegradable poly(ester urethane)s and poly(ester urethane urea)s for soft tissue-engineering applications

The development of biomimetic highly-porous scaffolds is essential for successful tissue engineering. Segmented poly(ester urethane)s and poly(ester urethane urea)s have been infrequently used for the fabrication of electrospun nanofibrous tissues, which is surprising because these polymers represent a very large variety of materials with tailored properties. This study reports the preparation of new electrospun elastomeric polyurethane scaffolds. Two novel segmented polyurethanes (SPU), synthesized from poly(ε-caprolactone) diol, 1,6-hexamethylene diisocyanate, and diester-diphenol or diurea-diol chain extenders, were used (Caracciolo et al. in J Mater Sci Mater Med 20:145–155, 2009). The spinnability and the morphology of the electrospun SPU scaffolds were investigated and discussed. The electrospinning parameters such as solution properties (polymer concentration and solvent) and processing parameters (applied electric field, needle to collector distance and solution flow rate) were optimized to achieve smooth, uniform bead-free fibers with diameter (~700 nm) mimicking the protein fibers of native extracellular matrix (ECM). The obtained elastomeric polyurethane scaffolds could be appropriate for soft tissue-engineering applications.     

Synthesis,characterization, and thermal stability of novel poly(azomethine-urethane)s and polyphenol derivatives derived from 2,4-dihydroxy benzaldehyde and toluene-2,4-diisocyanate

Up to date, only a few kinds of poly(azomethine-urethane)s (PAMUs) were synthesized and studied with thermal degradation steps. However, polyphenol based PAMUs including azomethine linkages have not been investigated yet. The polyurethanes were prepared by condensation reaction of 2,4-dihydroxybenzaldehyde (2,4-DHBA) with toluene-2,4-diisocyanate (TDI) under argon atmosphere. Synthesized polyurethane was converted to its poly(azomethine urethane) species (TP-2AP, TP-3AP, and TP-4AP) by graft copolymerization reactions with amino phenols (2-amino phenol, 3-amino phenol, and 4-amino phenol). Obtained poly(azomethine urethane)s were converted to their polyphenol species (P-TP-2AP, P-TP-3AP, and P-TP-4AP) by oxidative polymerization reaction (OP) using NaOCl as the oxidant. The structures of the obtained compounds were confirmed by FT-IR, UV–vis, ¹H NMR, and ¹³C NMR techniques. The molecular weight distribution parameters of the synthesized compounds were determined by the size exclusion chromatography (SEC). The synthesized compounds were also characterized by solubility tests, TG-DTA, and DSC. Fluorescence measurements were carried out in various concentrated DMF solutions to determine the optimum concentrations to obtain the maximal PL intensities.     

超支化聚对苯共聚物的合成及表征

利用Suzuki缩聚反应,合成了以1,3,6,8-(N-己基)咔唑为核的新型超支化聚对苯撑共聚物.用红外、核磁共振对聚合物的结构进行测定,表明咔唑以及吡啶单元成功引入聚合物中.聚合物可溶于四氢呋喃、氯仿和甲苯等有机溶剂.用凝胶渗透色谱法测得超支化聚合物的分子量在40000～110000之间,分子量随着1,3,6,8-(N-已基)咔唑含量的增加逐渐增加.超支化聚合物在溶液和薄膜状态下的吸收峰分别位于315～334nm和402～410nm之间.随着支化咔唑单元含量的增加,超支化聚合物的吸收峰均发生一定程度的蓝移.超支化聚合物在溶液和薄膜状态下的最大发射峰分别位于402～410nm和402～415nm之间,并且随着引入的支化咔唑单元含量的增加,分子内发生更加有效的分子内电荷转移,PL光谱发生略微的红移.     

Synthesis,characterization and fluorescence quenching of poly(fluorene-alt-enylenevinylene)s

Two poly(fluorine-alt-phenylenevinylene)s fluorescent conjugated polymers, poly(9,9-dioctylfluorene-alt-phenylenevinylene) (PFO/PPV1) and poly(fluorene-alt-2,5-dioctoxyphenylenevinylene) (PFO/PPV2), were obtained through a Heck polycondensation. The structures of the obtained polymers were characterized by FT-IR, ¹H-NMR and GPC. The thermal stabilities of the polymers were evaluated by TGA. The photophysical properties were studied by UV and photoluminescence (PL) spectroscopy both in solution and film. Their applications in the detection of nitro compounds were researched, and the results show high fluorescence quenching sensitivity of PFO/PPV1 towards nitro compounds such as 2,4-dinitrotoluene (DNT) and 4-nitrotoluene (p-NT) in solution and thin film.     

Synthesis, characterization and electrical properties of poly(dibromoaniline-co-aniline)s

The chemical copolymerization of aniline and 2,5-dibromoaniline or 2,6-dibromoaniline by oxidation with K₂Cr₂O₇ in H₂SO₄/acetonitrile media has been carried out. Copolymer composition can be effectively controlled varying the monomer feed ratio. When substituted aniline fraction is increased in the copolymer, the electrical conductivity () decreases; this effect is more important when 2,6-dibromoaniline is used. Thus, the conductivity can be controlled in a broad range, from 1.2 to 10^–6–10^–11 S·cm^–1 depending on the substituted aniline and the feed ratio. The relations between copolymer compositions and comonomer feed molar ratios shows that the aniline is slightly more reactive than dibromoanilines during the copolymerization process. All the copolymers were shown to be more processable than polyaniline.     

Synthesis, characterization and fluorescence quenching of poly(fluorene-alt-enylenevinylene)s

Two poly(fluorine-alt-phenylenevinylene)s fluorescent conjugated polymers, poly(9,9-dioctylfluorene-alt-phenylenevinylene) (PFO/PPV1) and poly (fluorene-alt-2,5-dioctoxyphenylenevinylene) (PFO/PPV2), were obtained through a Heck polycondensation. The structures of the obtained polymers were characterized by FT-IR, ¹H-NMR and GPC. The thermal stabilities of the polymers were evaluated by TGA. The photophysical properties were studied by UV and photoluminescence (PL) spectroscopy both in solution and film. Their applications in the detection of nitro compounds were researched, and the results show high fluorescence quenching sensitivity of PFO/PPV1 towards nitro compounds such as 2,4-dinitrotoluene (DNT) and 4-nitrotoluene (p-NT) in solution and thin film.     

Synthesis and characterization of nitrated and aminated poly(phenylene sulfide) derivatives for advanced applications

Nitrated and aminated poly(phenylene sulfide) (PPS) derivatives with different extent of modification were synthesized in a one-pot reaction in suspension. Their substitution degree was determined from both elemental analysis and TGA curves. FT-IR and NMR spectra demonstrated the effectiveness of the functionalization reactions, showing the appearance of bands related to the substituent groups. A progressive reduction in thermal stability was observed as the number of functional groups increased. Aminated derivatives were thermally less stable and exhibited higher solubility in aprotic polar solvents than the corresponding nitrated polymers. DSC thermograms revealed a diminution in the crystallization temperature and a rise in the glass transition with increasing functionalization degree, since the presence of substituent groups inhibits the rotation of consecutive elements of the polymer chain. The level of crystallinity decreased upon increasing chain modification, as evidenced from X-ray diffractograms. The steric hindrance of the substituents disrupts the chain packing, leading to smaller crystals. These derivatives are expected to have applications in electromembranes and as matrix materials for the fabrication of high-performance composites suitable for structural and non-structural components.     

Synthesis and characterization of novel triblock copolymers comprising poly(tetrahydrofuran) as a central block and poly(-benzyl -glutamate)s as outer blocks

BACKGROUND: Bioactive and biodegradable polyurethanes (BDPUs) have drawn much attention in recent years. As part of the research program to search for novel prepolymers for BDPUs, a study was carried out on the synthesis and characterization of triblock copolymers comprising poly(tetrahydrofuran) as a central block and poly(?-benzyl L-glutamate)s as outer blocks. RESULTS: A new macroinitiator terminated with phenylalanine was first prepared from the condensation of a distal hydroxy poly(tetrahydrofuran) with N-tert-butoxycarbonyl L-phenylalanine in the presence of dicyclohexylcarbodiimide, followed by removing the protecting group. Then, it was employed to initiate the ring-opening polymerization of ?-benzyl L-glutamate N-carboxyanhydride in varying feeding ratios to give rise to the targeted triblock copolymers. CONCLUSIONS: The length of the outer poly(?-benzyl L-glutamate) blocks was well tailored by varying the monomers to macroinitiator feeding ratio. All the triblock copolymers exhibited a nearly symmetrical and unimodal molecular weight distribution while only one distinct glass transition temperature was evidenced from -10°C to 25°C.     

Synthesis and characterization of fluorescent poly(oxadiazole)s containing 3,4-dialkoxythiophenes

We report the synthesis, optical and electrochemical details, and properties of three conjugated copolymers (P1–P3) consisting of alternate hole-transporting thiophene derivative and electron-transporting 1,3,4-oxadiazole units. The polymers are prepared using the precursor polyhydrazide route. The polymers have well defined structure and exhibit good thermal stability with the onset decomposition temperature in nitrogen at around 300 °C. All the polymers are soluble in organic solvents such as DMF, DMSO, NMP and in strong organic acids like trifluoroacetic acid. The optical and charge-transporting properties of the polymers are investigated by UV–visible spectroscopy, fluorescence emission spectroscopy and cyclic voltammetry. The UV–visible absorption spectra of polymers in solution showed a maximum at around 400 nm. The polymers depicted green fluorescence both in solution and as thin films. Cyclic voltammetry studies reveal that these copolymers have low-lying LUMO energy levels ranging from −3.28 to −3.36 eV and high-lying HOMO energy levels ranging from −5.5 to −5.56 eV, which indicated that they may be promising candidates for electron-transporting or hole-blocking materials in light-emitting diodes.     

Synthesis and characterization of a novel multiblock copolyester containing poly(ethylene succinate) and poly(butylene succinate)

Multiblock copolyester (PBS-b-PES) containing poly(butylene succinate) (PBS) and poly(ethylene succinate) (PES) was successfully synthesized by chain-extension of dihydroxyl terminated PBS (HO-PBS-OH) and PES (HO-PES-OH) using 1,6-hexmethylene diisocyanate (HDI) as a chain extender. The chemical structures, molecular weights, crystallization behaviors, thermal and mechanical properties of the copolyesters were characterized by proton nuclear magnetic resonance spectroscopy (¹H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), wide-angle X-ray diffraction (WAXD), tensile testing and hydrolytic degradation. High-molecular-weight copolyesters with M_w more than 2.0 × 10⁵ g mol⁻¹ were easily obtained through chain-extension. The copolyesters showed a single glass transition temperature (T_g) which increased with PES content. The melting point temperature (T_m) and relative degree of crystallinity (X_c) of the copolyesters decreased first and then increased with PES content. The copolyesters manifested excellent mechanical properties, for example, PBS₅-b-PES₅ had fracture stress of 61.8 MPa and fracture strain of 1173%. The chain-extension reaction provided a very effective way to produce high molecular weight multiblock copolyesters.     

聚乙二醇改性聚乳酸的合成与性能表征

以外消旋乳酸(D,L-LA)和不同数均分子量(Mn)的聚乙二醇(PEG)为原料,通过熔融缩聚法,合成了系列聚乳酸聚乙二醇(PLEG)。最佳工艺条件为:以(Sn(Oct)2)为催化剂,m(Sn(Oct)2)为0.8%,n(PEG)∶n(D,L-LA)=1∶600,聚合温度170℃,压力0.096 MPa条件下,反应8h。用特性粘度测试、FT-IR、XRD、接触角等对其进行表征,实验结果表明系列PLEG中PLEG-800接触角为63°,表明其亲水性能最好;PEG-800和乳酸共聚合成的PLEG的粘均分子量最大,可达48997,与PDLLA相比,结晶度有较大提高,亲水性得到改善。     

高分子量聚L-乳酸的合成和表征

采用丙交酯开环聚合合成聚L-乳酸(PLLA),研究了引发剂用量、聚合时间对聚L-乳酸分子量的影响.采用FTIR、DSC、TG分析方法对聚乳酸的结构和热性能加以表征.研究结果表明通过对聚合时间以及引发剂用量的控制,合成出高分子量聚L-乳酸.FTIR分析结果证实了聚L-乳酸的结构,DSC分析表明合成出的聚L-乳酸玻璃化转变温度为62℃,结晶度达到42.3%;TG分析表明聚L-乳酸热分解温度为299℃.     

Synthesis and characterization of a novel photocrosslinkable fluorinated poly(arylene ether) for optical waveguide

To improve its chemical resistance and mechanical stability, a novel fluorinated poly(arylene ether) bearing a photocrosslinkable chalcone group in the main chain was successfully synthesized by means of polycondensation between 4,4′-dihydroxychalcone and decafluorobiphenyl in N,N-dimethylacetamide in the presence of the excess anhydrous potassium carbonate. The structure of polymer was characterized by ¹H NMR and ¹⁹F NMR spectroscopies. The resulting polymer shows excellent solubility in common organic solvents, high glass transition temperature and good thermal stability. Crosslinking of the resulted polymer has been demonstrated by UV irradiation. Near-IR spectra of polymer film before and after UV irradiation show no absorption at the telecommunication wavelengths of 1310 and 1550 nm, demonstrating that the resulting polymer is good candidate material for optical waveguide application.     

一种含芴聚芳醚酮质子交换膜的合成与表征

采用先磺化法,通过控制双酚芴、二氟苯甲酮和磺化二氟苯甲酮的比例,合成了磺化聚芴醚酮,对其结构进行表征,并制备成质子交换膜,对其性能进行了研究.结果表明其具有高的热稳定性、化学稳定性及足够的机械性能.同时还具有较好电池性能.