2-(p-十二烷氧基苯乙炔基)吡嗪-5-羧酸的合成及成膜性

在含有吡嗪环的对位双环羧酸化合物中,2-(p-十二烷氧基苯基)吡嗪-5-羧酸具有良好的成膜性^[1,2].在苯环和吡嗪环间引入不饱和键,合成的2-(p-十二烷氧基苯乙炔基)吡嗪-5-羧酸,由于其具有较长的共轭体系,因而分子排列的取向性更好,形成的LB膜更致密.该化合物尚未见报道.本文报道该化合物的合成方法及成膜的初步结果.     

不饱和聚酯树脂的减收缩作用(Ⅰ)——几种常用高分子的减收缩作用

不饱和聚酯树脂(简称UP-树脂)固化时体积收缩率高达7％～10％,限制了它的应用范围,七十年代以来,国外已开始生产低收缩不饱和聚酯树脂,并有不少这方面的专利,我国尚未见有关研究低收缩树脂的报道,我们考察了PS、PE、PVC、330聚醚及醇酸树脂的减收缩效果并用于191 UP-树脂,制成了无填料浇铸板及散状模塑料,测定了它们的体积收缩率、线收缩率以及力学和热学性能,发现PS、PE、PVC及330聚醚只宜做散状模塑料,而醇酸树脂则既可做散状模塑料又可做无填料浇铸板,性能均较好。     

选择性催化混合单体制备多组分聚酯的研究进展

以聚乳酸和聚碳酸酯等为代表的生物可降解高分子材料已被应用于包装材料和生物医用等领域.然而受链段结构的影响,这类均聚物材料在实际应用中受到了一定限制.将不同性质聚合物链段通过共价键连接形成的嵌段共聚物具有组分均匀、性能可控等优点,是优化材料性能的一种方法.本文概述了环酯、环氧化物和CO2(或环状酸酐)的多元共聚反应合成嵌...     

Homogenization process caused by competition between phase separation and ester‐interchange reactions in immiscible polyester blends: A Monte Carlo simulation

The homogenization process caused by competition between phase separation and ester‐interchange reactions in immiscible polyester blends was investigated via the Monte Carlo simulation method. Phase separation and ester‐interchange reactions were performed simultaneously with the one‐site bond fluctuation model on a homogeneous blend of immiscible polyesters. Three different values of the repulsive pair‐interaction energy (E_AB) between segments A and B and two trial ratios of phase separation to ester‐interchange reactions at a given E_AB were introduced to examine the competition between them. Phase separation was monitored by the calculation of the collective structure factor, and copolymerization was traced by the calculation of the degree of randomness (DR). In all cases, as the homogenization proceeded, the maximum intensity of the collective structure factor initially increased, reached a maximum, and finally decreased, whereas the peak position where the structure factor had a maximum shifted downward in the early stage and then remained unchanged after the intensity of the collective structure factor reached the maximum. This indicates that during the homogenization process, the domain size did not change significantly after phase‐separated structures were developed distinctly. In this simulation, phase‐separated structures were traced until the DR was above 0.8. This result indicates that homogenization can be accomplished via homogeneous ester‐interchange reactions over most of the polyester chains because copolyesters resulting from ester‐interchange reactions do not act as an efficient compatibilizer. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 590–598, 2000     

Polyesters with semifluorinated side chains: A proposal for the solid‐state structure

A proposal for the solid‐state structure of poly(p‐phenylene isophthalate) with oxydecylperfluorodecyl side chains is presented, which was calculated by the new Rietveld refinement program BGMN®. A triclinic unit cell with a = 0.575 nm, b = 4.06 nm, c = 2.1 nm, α = 91.2°, β = 85.7°, and γ = 66.1° was obtained using space group symmetry P1¯ (No. 2) with Z = 2. All fractional atom coordinates, reflections and structure factors F were determined. The results show that highly occupied netplanes lie in plane and perpendicularly to the side chains. It may be supposed that these net planes will form the low‐energy surface of the polymer. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1617–1625, 2000     

Synthesis and characterization of new soluble polyesters derived from various cardo bisphenols by solution polycondensation

A series of new polyesters was prepared from terephthaloyl (or isophthaloyl) chloride acid with various cardo bisphenols on solution polycondensation in nitrobenzene using pyridine as hydrogen chloride quencher at 150 °C. These polyesters were produced with inherent viscosities of 0.32–0.49 dL · g⁻¹. Most of these polyesters exhibited excellent solubility in a variety of solvents such as N,N‐dimethylformamide, tetrahydrofuran, tetrachloroethane, dimethyl sulfoxide, N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidinone, m‐cresol, and o‐chlorophenol. The polyesters containing cardo groups including diphenylmethylene, tricyclo[5.2.1.0^2,6]decyl, tert‐butylcyclohexyl, phenylcyclohexyl, and cyclododecyl groups exhibited better solubility than bisphenol A–based polyesters. These polymers showed glass transition temperatures (T_g's) between 185 °C and 243 °C and decomposition temperatures at 10% weight loss ranging from 406 °C to 472 °C in nitrogen. These cardo polyesters exhibited higher T_g's and better solubility than bisphenol A‐based polyesters. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4451–4456, 2000     

Synthesis and properties of phosphorus-containing polyesters derived from 2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4- hydroxyethoxy phenylene

A series of phosphorous-containing aliphatic polyesters were synthesized by high-temperature solution condensation of 2-(6-oxido-6H-dibenz〈c,e〉〈1,2〉oxaphosphorin-6-yl)-1,4-hydroxyethoxy phenylene (III) with various aromatic acid chlorides in o-dichlorobenzene. All polyesters are amorphous and readily soluble in many organic solvents such as DMAc, NMP, DMSO, and o-dichlorobenzene at room temperature or upon heating. These polyesters are thermally quite stable. The glass transition temperatures of these aliphatic polyesters ranged from 126.6 to 162.2°C. The degradation temperatures (T_d onset) in nitrogen ranged from 424 to 448°C, and the char yields at 700°C are 20–32%. The activation energies of degradation ranged from 160.9 to 226.0 kJ/mol. The LOIs of these polyesters ranged from 36 to 43. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3051–3061, 1998     

Monte carlo simulation of copolymerization by ester interchange reaction in miscible polyester blends

The effects of reaction variables on the degree of randomness in copolymers formed by ester interchange reaction in miscible polyester melt blends were systematically investigated using a Monte Carlo method. Three reaction variables such as the molecular weight difference between two component polymers, the blend ratio, and the reaction ratio of end attack to bond flip, were particularly considered on the cubic lattice model. Ester interchange reactions were assumed to take place during reptational chain motions. It was found that the copolymerization was dependent upon the molecular weight difference and reaction ratio: As the molecular weight difference becomes smaller and when both end attack and bond flip reactions are involved simultaneously, the copolymerization is accelerated. However, the blend ratio does not affect the copolymerization process. This result is discussed in relation to the polymer chain conformation for the ester interchange reaction. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1637–1645, 1998     

Phase and orientational behaviors in liquid crystalline main-chain/side-group block copolymers

The phase and orientational behaviors of a series of liquid crystalline (LC) AB-type diblock copolymers comprising thermotropic main-chain (MC) polyester and side-group (SG) polymethacrylate blocks were investigated by X-ray diffraction. The MC and SG blocks were phase separated and gave rise to their individual mesophases that coexisted at equilibrium. The samples were oriented by using either a magnetic field or a mechanical field. In magnetically aligned samples both the MC and SG microphases were oriented with their smectic planes orthogonal to the magnetic field direction, independent of the copolymer composition. Mechanically aligned, fiber samples showed different orientations of the MC and SG smectic planes for different sample compositions. In this case the disposition of the smectic planes of the MC and SG blocks was driven by the relative length of the two blocks. Some features of the X-ray patterns of the copolymers were compared to those of the MC and SG homopolymers. In addition, the MC smectic domains crystallized on annealing without affecting the orientation that had been achieved by applying a magnetic field. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 21–29, 1998     

Blends of polyester having amino sulfonic acid moieties with poly(vinyl alcohol) and their metal complex formation

Polyester having amino sulfonic acid moieties (TBES) was prepared by a liquid/solid biphase polycondensation of terephthaloyl chloride (TPC) and N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES) in trimethyl phosphate (TMP) using triethylamine (TEA) as an acid acceptor. Blends of TBES with PVA and their metal complexes with Ni²⁺ and Co²⁺ ions were prepared. A strong interaction was observed between TBES and PVA. An electric conductivity of 10⁻⁶ S cm⁻¹ was attained for the blend films containing about 5 wt % water. A coordination structure with two chelate rings is proposed for the metal complex with Ni²⁺ and Co²⁺ ions when the molar ratio of amino sulfonic acid groups in TBES to metal ions is larger than 2. Polymer blends complexed with Ni²⁺ or Co²⁺ ions result in semi-interpenetrating polymer networks from chelate formation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3561–3569, 1997