酞侧基聚芳醚酮的撕裂不稳定性

酞侧基聚芳醚酮的撕裂不稳定性韩艳春，杨宇明，李滨耀，冯之榴（中国科学院长春应用化学研究所长春１３００２２）关键词酞侧基聚芳醚酮，撕裂不稳定性，延性撕裂由Ｐａｒｉｓ等［１］根据弹塑性断裂理论发展的撕裂模量理论是表征延性材料失稳的重要理论之一。当裂纹扩展...     

酞侧基聚芳醚砜／对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物共混物的研究

酞侧基聚芳醚砜／对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物共混物的研究李刚，殷敬华，李滨耀（中国科学院长春应用化学研究所，长春，１３００２２）关键词酞侧基聚芳醚砜，热致性液晶高聚物，原位复合材料，对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物将热塑性树脂与热...     

含间苯基聚芳醚酮的合成与性能研究

含间苯基聚芳醚酮的合成与性能研究林权，张万金，吴忠文，尹玖梅（吉林大学化学系，长春，１３００２１）（中国科学院长春应用化学研究所）关键词聚芳醚酮，间苯基，熔点，结晶度聚芳醚酮作为一类耐高温特种工程塑料，由于具有优异的热、电、机械性能，已被广泛应用于电...     

含不同取代基的Cardo聚芳醚酮──合成与表征

含不同取代基的Ｃａｒｄｏ聚芳醚酮──合成与表征王忠刚,陈天禄,徐纪平（中国科学院长春应用化学研究所长春１３００２２）关键词Ｃａｒｄｏ聚芳醚酮,合成与表征,自由体积,玻璃化转变温度酚酞型Ｃａｒｄｏ聚芳醚酮（ＰＥＫ－Ｃ）是长春应化所合成的一种新型高一Ｔ,...     

酞侧基聚芳醚砜和聚芳醚酮共混物的高温流变行为

用锥板粘度计测试了酞侧基聚芳醚砜（ＰＥＳ－Ｃ）和酞侧基聚芳醚酮（ＰＥＫ－Ｃ）及其共混物的熔体流变行为．试样的流动活化能分别为１４５、１３３和１１２ＫＪ／ｍｏｌ．共混物的熔体粘度显著低于ＰＥＳ－Ｃ和ＰＥＫ－Ｃ粘度的对数加和值．并证明试样的熔体流动性和加工稳定性都已达到注射成型工艺的要求．     

氢键型聚芳醚酮共聚物的合成与表征

氢键型聚芳醚酮共聚物的合成与表征王忠刚，陈天禄，徐纪平（中国科学院长春应用化学研究所长春１３００２２０）关键词氢键，聚芳醚酮，合成，表征高分子链之间的氢键相互作用可以有效地提高聚合物的性能［１，２］．本工作通过共聚反应，在酚酞型聚芳醚酮ＰＥＫ－Ｃ分子...     

高性能工程塑料的流变和加工性能──Ⅰ.酞侧基聚芳醚酮的毛细管挤出行为

酚测基聚芳醚酮（PEK－C）和酞侧基聚芳醚矾（PES－C）〔‘·‘I是我国在80年代自行开发的高性能工程塑料．这两种材料在其主链结构上都附有酚酞侧基，而且几乎不含脂肪族基团，都呈无定形结构，具有耐热性好（T。＞220C），强度高（室温下拉伸强度大于100MPa）的特点．PEK－C、PES－C的特点是加工温度高、熔体粘度大，使其加Xi与通用塑料相比要困难得多．本文报道了PEK－C的挤出流动行为的研究结果．白色粉末状的PEK－C由长春应用化学研究所徐州工程塑料公司提供，在25C氯仿中的增比粘度为O．49，先将其放在140℃的真空烘箱中…     

带酞基聚芳醚酮超滤膜的研究──Ⅰ带酞基聚芳醚酮超滤膜的制备与性能

以带酞基聚芳醚酮（ＰＥＫＭ）为膜材料，用相转换法制备了ＰＥＫ—Ｃ不对称超滤膜，研究了铸膜液的主要组分对膜的孔结构与超滤性能的影响。     

含间苯基聚醚醚酮酮的合成与性能研究

含间苯基聚醚醚酮酮的合成与性能研究林权，王一凡，张万金，吴忠文，尹玖梅（吉林大学化学系，长春，１３００２３）（中国科学院长春应用化学研究所）关键词聚醚醚酮酮，间苯基，熔点，玻璃化转变温度聚芳醚酮类高聚物具有优异的热、电、机械性能．全对苯基位聚醚醚酮酮...     

分子结构对聚芳醚酮薄膜透气性的影响

分子结构对聚芳醚酮薄膜透气性的影响王忠刚，陈天禄，徐纪平（中国科学院长春应用化学研究所长春１３００２２）关键词聚芳醚酮，气体分离膜，结构－性能关系为了改善聚合物薄膜的透气性能，开发具有高透气性和高选择性的膜材料，人们对膜分子结构与透气性能间的关系进行...     

Process dependence of pressure-specific volume-temperature measurement for amorphous polymer: Acrylonitrile-butadiene-styrene

The process dependence of pressure-specific volume-temperature (pvT) measurement for an amorphous polymer, acrylonitrile-butadiene-styrene (ABS), was investigated. The influences of different measurement processes (heating, cooling, compression, and decompression with different rates) were considered in the pvT measurements. The pvT measurements of isobaric cooling and heating with different cooling and heating rates (2, 5, and 10 °C/min) and isothermal compression and decompression with different compression and decompression rates (up to 920 bar/s) were conducted. The testing temperature ranged between 40 and 230 °C and the pressure ranged between 20 and 2200 bar. The obtained results demonstrated that the pvT diagram will be significantly different depending on the direction in which the pressure or temperature is changing and also on the rate of the change. Isobaric pvT diagrams are different between cooling and heating. Fast cooling accelerates phase transitions, while fast heating reverses. Specific volume at the same pressure and temperature in decompression process is lower than that in compression. Compression and decompression leads to different pvT curves. Compression and decompression rates have different effects on specific volume in different states.     

Thermal conductivity behaviour of polymers around glass transition and crystalline melting temperatures

The thermal conductivity of five semi-crystalline and four amorphous polymers was determined within a wide range of temperature, starting at room temperature and going up to temperatures above the polymer melting point (Tm) for semi-crystalline polymers or above the glass transition temperature (Tg) for amorphous polymers. Two transient techniques were employed in the experimental investigation: the hot wire technique for the group of amorphous polymers, and the laser flash technique for the semicrystalline polymers. As expected, the experimental results show that Tg exerts a measureable influence on the thermal conductivity of amorphous polymers. In the case of semi-crystalline polymers, a singular behaviour of the thermal conductivity is observed within the Tm range. In order to explain the anomalous behaviour, the influence of these transition temperatures on the thermal conductivity behaviour with temperature has been analysed in terms of a phonon conduction process and temperature variations of specific heat and modulus of elasticity of the analyzed polymers.     

Pressure dependence of the thermal conductivity,thermal diffusivity,and specific heat of some polymers

The pressure dependence of the specific heat of poly(methyl methacrylate), polystyrene, and atactic and isotactic polypropylene was determined from simultaneous measurements of thermal conductivity and diffusivity in a cylindrical geometry at 300°K and in the pressure range 0–37 kbar. The thermal conductivity and the diffusivity both increase strongly with pressure, while the specific heat decreases. The pressure dependencies are most pronounced at low pressures. The results are compared with other experimental results and with theoretical calculations.     

Cooling rate dependence of specific heat in systems out of equilibrium

The anomaly of specific heat in systems out of equilibrium, especially the measurement procedure dependence of specific heat, is investigated by means of free energy landscape. Introducing measurement procedure which is based on experimental method, we propose a calculation method of specific heat in systems out of equilibrium and find an abrupt change in specific heat between annealed and quenched states. For longer observation time the change in specific heat occurs at lower temperature and becomes sharper. For slower cooling of a system the transition temperature becomes lower. This cooling rate dependence of the transition temperature is consistent with experiments and thus the abrupt change in specific heat can be regarded as the glass transition which is thermally identified.     

A combined photoacoustic DSC for simultaneous temperature modulated measurements: does it really work?

Combination of two techniques, photoacoustic (PA) and differential scanning calorimetry (DSC), is a combination of quasi stationary thermodynamic DSC method and nonstationary dynamic PA method. Especially favorable and easy to realize is the combination with power compensated type of DSC. It has several advantages over the use of two techniques separately and allow to perform measurements simultaneously. The most obvious is simultaneous determination of thermodynamic properties such as specific heat, heat of transition and dynamic properties such as effusivity, thermal conductivity at the different phase transitions and complex specific heat at the glass transition. Unlike other temperature modulated techniques PA–DSC is especially suitable for studying polymer materials since their low thermal conductivity is an additional advantage. Conditions for simultaneous measurements are examined. It is proved that the combination of two techniques and necessary changes in construction do not essentially change adequate work of the instrument. A little disbalance of DSC operation due to the construction change can be corrected simply by recalibration. The procedures for testing and calibration for the proper operation of the combined PA–DSC are given together with some details of experimental methodology. Several measurements could serve as examples of widespread applicability of PA–DSC to study different types of phase transitions as well as time dependent processes such as glass transition.     

Static and dynamic thermal quantities near the consolute point of the binary liquid mixture aniline-cyclohexane studied with a photopyroelectric technique and adiabatic scanning calorimetry

We studied the thermal conductivity, thermal effusivity, and specific heat capacity at constant pressure of the critical binary liquid mixture aniline-cyclohexane near the consolute point, using a photopyroelectric (PPE) technique and adiabatic scanning calorimetry (ASC). According to recent theoretical predictions based on renormalization group theory calculations, a substantial (but not diverging) enhancement in the thermal conductivity in the homogeneous phase near the critical temperature was expected for this binary system near the consolute point. However, within an experimental precision of 0.05%, we found no deviation from linear behavior in the range of 5 K above Tc down to Tc. The specific heat capacity calculated from the results for the thermal conductivity and effusivity is in good agreement with that measured by ASC. For the ASC results, the theoretical power law expression with the Ising critical exponent was fitted to the specific heat capacity both above and below the transition temperature. Good agreement with theory was found both for the amplitude ratio and the two-scale universality.     

Thermal relaxation of glycerol and propylene glycol studied by photothermal spectroscopy

In this paper we report on experimental data for the frequency and temperature dependence of the thermal properties of supercooled glycerol and propylene glycol. By using a photopyroelectric method the specific heat capacity and thermal conductivity were separately determined in a bandwidth of several decades. We have recently shown that the thermal conductivity has no relaxation behavior, which simplifies the analysis of our results. The relaxation behavior of the specific heat capacity is compared with literature results for other physical quantities and a detailed analysis of the temperature dependence of the relaxation parameters is presented.     

Effects of thermal history on enthalpy relaxation

The effects of the thermal history on enthalpy relaxation in polymethylmethacrylate (PMMA) have been studied by differential scanning calorimetry (DSC). The temperature dependence of specific heat capacity in the liquid and glassy states, that of relaxation time and the exponent of the Kohlrausch–Williams–Watts function have been obtained by the measurement of the response of heat flux to the sinusoidal temperature variation. The phenomenological model equation as an extension of linear rheology has been applied to enthalpy relaxation. The evolution of entropy under a given thermal history same as the experiment has been calculated and compared with the DSC results. The calculated results reproduce two peaks of specific heat capacity at lower and higher temperatures in the glass transition region: the former is characteristic of PMMA and the latter is observed in typical glassy polymers.     

Effect of indium additive on thermal transport properties of Se–Te–Cd multi-component chalcogenide glasses

The thermal conductivity, thermal diffusivity and specific heat per unit volume of twin pellets of Se₇₅Te_15?Cx Cd₁₀In _x (x?=?0, 5, 10 and 15) glasses, were carried out at room temperature by transient plane source technique. Results indicated that both values of thermal conductivity (??) and thermal diffusivity (??) are varied with In (indium) content and highest for 5?at.% of In, whereas the specific heat per unit volume is almost constant with increase of indium concentration. This shows that Se₇₅Te₁₀Cd₁₀In₅ glass can be considered as a critical composition at which the alloy becomes chemically ordered and most thermally stable than other compositions. This compositional dependence behaviour of thermal conductivity and thermal diffusivity can explained in terms of iono-covalent type bond which In makes with Se and Te as it is incorporated in Se?CTe?CCd glasses.