耐高温含氟聚芳醚酮和聚芳醚砜的合成与性能研究

通过三步反应合成新的含氟双酚单体3,4-二氟苯基对苯二酚,由该含氟双酚单体、4-氟苯基对苯二酚、邻苯基对苯二酚分别与4,4′-二氟二苯酮、4,4′-二氯二苯砜经亲核缩聚反应,制备了一系列新型聚芳醚酮和聚芳醚砜。采用 FT-IR、DSC、TGA及XRD手段等对聚合物的结构和性能进行了表征和研究,结果表明：合成的聚芳醚酮和聚芳醚砜具有优异的耐热性能,玻璃化转变温度分别在150~159 ℃和177~196 ℃之间,氮气中5 %热失重温度分别在527 ℃和507 ℃以上。合成的聚芳醚酮和聚芳醚砜具有良好的溶解性,室温下能溶解在N-甲基吡咯烷酮、二甲基乙酰胺、氯仿等有机溶剂中。     

特种工程塑料聚芳醚酮

介绍了聚芳醚酮的发展概况、分类及其物化性能;重点对PEEK的性能及应用进行详细阐述;概述了PEEK 的最新研究成果,并指出其今后发展趋势。     

杂环聚芳醚砜酮环氧与DDE的固化动力学研究

用示差扫描量热仪(DSC)对杂环聚芳醚砜酮环氧(E-PPESK)/二氨基二苯醚(DDE)固化体系的固化反应过程进行了分析,并用Kissinger和Ozawa方法分别求得体系固化反应的表观活化能76.95 kJ /mol和80.58 kJ /mol,结合Crane公式求出了该固化体系的反应级数为0.93.确定了DDE作为固化剂的固化反应条件.     

聚芳醚酮/含甲基侧基聚芳醚砜醚酮酮的合成与表征

以2，2’-二甲基-4,4'-二苯氧基二苯砜(o-CH3-DPODPS)、二苯醚(DPE)和对苯二甲酰氯(TPC)为单体，在无水A1C13、1，2-二氯乙烷和N，N-二甲基甲酰胺存在下，通过低温溶液缩聚反应。合成了一系列新型含甲基侧基的聚芳醚酮／聚芳醚砜无规共聚物。用FT-IR，WAXD，DSC和TG等方法对聚合物进行了表征。结果表明，随着2,2'-二甲基-4，4'-二苯氧基二苯砜含量的增加，共聚物的玻璃化转变温度逐渐提高，熔融温度则逐渐下降。     

聚芳醚砜酮纤维的热性能

采用DSC、TG测定了含联苯结构聚芳醚砜酮 (PPESK)纤维的热性能 ,结果表明 ,纤维的玻璃化温度随砜酮比的增大而提高 ,纤维的起始分解温度大于 463℃。当砜酮比为 15 / 85 ,5 0 / 5 0 ,75 / 2 5时 ,纤维的玻璃化温度分别为 2 5 7.62 ,2 78.64 ,2 79.71℃ ;热分解活化能分别为 15 0 .8,2 19.9,195 .5kJ/mol;热分解反应级数分别为 1,1.76,1级     

间位苯基取代聚芳醚砜醚酮酮的合成与性能研究

以4,4′-二苯氧基二苯砜(DPODPS)、对苯二甲酰氯(TPC)和间苯二甲酰氯(IPC)为单体,无水AlCl3/二氯乙烷(DCE)/N,N-甲基甲酰胺(DMF)为催化溶剂体系,通过低温溶液共缩聚反应,合成系列聚芳醚砜醚酮酮(PESEKKs),用IR、DSC、WAXD、TG等技术对聚合物进行了结构和性能的表征,研究结果表明,随着高分子主链中间位苯基结构单元的增加,对共聚玻璃化转变温度(Tg)和热分解温度(Td)影响不大,熔融温度(Tm)和结晶则逐渐降低,但仍保持良好的耐热性,溶解性等到很大改善。     

双酚A型聚芳醚酮的热分解动力学研究

用热重(TG)法研究了双酚A型聚芳醚酮(PAEK)的热分解动力学,计算了热分解动力学参数.结果表明,双酚A型PAEK的热分解符合无规引发分解模型,热分解过程为一级反应.以Kissinger最大失重率法求得热分解反应的反应活化能E为201.909kJ/mol;以Ozawa等失重百分率法求得反应活化能E为211.398kJ/mol;频率因子A值为2.306×10~(14)～9.173×10~(14)min~(-1);预测N_2中267℃失重5%的热老化寿命为10 a.     

新型高性能热塑性工程塑料—聚芳醚酮树脂

介绍了近十年来发展的一种新型热塑性工程塑料——聚芳醚酮树脂。它具有优良的高温机械性能、难燃性、电气性、成型加工性、抗幅射性及耐化学腐蚀性,是一种前途广阔的工程塑料。     

新型聚芳醚砜酮超滤膜污染与膜阻力研究

采用新型聚芳醚砜酮(PPESK)超滤膜为分离介质,以炼油污水为研究对象,测定了膜污染和膜阻力.结果表明,PPESK超滤膜在100 kPa下的初始通量为480 L·m-2·h-1,自身阻力为0.78mm-1;在超滤膜运行过程中,溶液通量随运行时间呈指数衰减,通量衰减由60%增加到95%时,膜污染阻力由0.69nm-1增大到5.68 nm-1,膜污染阻力占总阻力的分数从43.95%增大到86.72%,其中不可逆膜污染阻力大小为0.20nm-1.PPESK超滤膜对迭标炼油污水过滤时,因膜污染造成通量衰减,经化学清洗能够得到较大程度的恢复.     

聚芳醚砜酮溶液凝固相分离的研究

研究了聚芳醚砜酮的N-甲基吡咯烷酮溶液在凝固剂作用下的凝固相分离条件,测定了相分离时凝固剂种类、凝固液浓度、凝固温度和磺化处理对凝固液的凝固值和溶剂临界浓度的影响。结果表明水的凝固值最小,是一种强凝固剂;随凝固剂浓度和温度的提高,凝固值增大,临界浓度基本不变;磺化处理能够提高凝固值,从而缓和相分离剧烈程度。     

Thermal and thermooxidative degradation of engineering thermoplastics and life estimation

This investigation deals with the thermal or thermooxidative degradation behavior of three engineering polymers [e.g., poly(ethylene terephthalate) (PET), poly(ether sulfone) (PES), and poly(ether ether ketone) (PEEK)] by using thermogravimetry‐coupled mass spectrometry (TG‐MS) analysis. The experiments were conducted both in argon and in air separately to study the changes in the degradation pattern of the polymers under varied sample environments. The samples were subjected to a programmed heating rate of 10°C/min and a temperature range from ambient to 800°C. For all these polymers, the decomposition rate, percentage weight loss, and the nature of the evolved gases were found to vary while changing the environment from argon to air. Methods of nonisothermal kinetic analysis, proposed by Flynn and Wall, and the shelf life estimation, proposed by Toop, have been described. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1737–1748, 2004     

PGLA热降解性能的研究

使用热重分析仪（TG）对聚乙丙交酯（PGLA）与聚乙交酯（PGA）的热降解性能进行测试,并通过Kissinger、Flynn-wan-ozawa和Friedman 3种方法计算其降解过程中的活化能Ea。结果表明,PGLA的热稳定性较PGA更好,3种方法均能较好的分析其降解过程,当使用Flynn-wan-ozawa法拟合时,其线性相关性较好。     

Thermal degradation of shale oils: 1. Kinetics of vapour phase oil degradation

As vertical modified in-situ retorts (VMIS) have been scaled up and tested, the overall oil yield has declined and is generally lower than that observed in an above-ground process. This reduced oil yield could adversely affect the economics of VMIS retorting. Diminished yields are attributed to a combination of factors associated with scale-up such as in complete rubblization, wide particle size distributions (large blocks of shale), and poor flow distributions. Additionally, oil losses can occur by comparatively long exposure of the oil vapours to high temperatures, by exposure to successive condensation and revaporization of the oil as it travels down the retort, and finally by long time thermal exposure of the condensed oil retained in the bottom portion of large VMIS retorts. To study such vapour phase degradation of shale oil using oil produced from Occidental Petroleum's No. 6 VMIS retort, a tubular continuous flow reactor, with an on-line gas chromatograph for gas composition monitoring was used to study thermal degradation of shale oil under retorting conditions. Oil and a combination of gases including steam were metered into the preheater and then the vapours passed into a quartz tubular reactor where the temperature and residence time of the gaseous mixture were controlled. Complete mass balances were performed giving the weight fraction of oil converted to noncondensable hydrocarbon gases and coke. This experimental design is novel because high temperature thermal degradation of shale oil was studied for the first time under steady state flow conditions with carefully controlled residence time and temperature. A range of temperatures (425–625 °C) and residence times (2–10 s) were used in a series of factorial-designed experiments (3²) to accurately determine the effects of these variables. Results of the study showed that the addition of steam to the carrier gas did not reduce oil degradation losses but did react with the coke thereby changing the product gas composition and quantity. A first-order oil degradation rate expression was used to model the rate of oil loss. The calculated activation energy was 17.3 kcal mol^?1. Chemical analyses of the product liquids and gases confirmed previously reported findings that the oil loss indices (alkene/alkane, ethylene/ethane, naphthalene/(C₁₁ + C₁₂), and gas/coke) increase with increasing oil degradation.     

Curing and thermal degradation behavior of epoxy-based vitrimers

Epoxy with associative covalent adaptable networks (CANs), called vitrimer, is reported to be promising to realize the recyclable utilization. The typical epoxy vitrimers are synthesized from diglycidyl ether of bisphenol A and dicarboxylic catalyzed by triazabicyclodecene (TBD). The study on the curing and thermal degradation behavior facilitates in-depth understanding of the associative CANs. In this work, the effect of TBD on the curing and thermal degradation behavior is investigated via curing kinetics and thermal degradation performance analysis. The results reveal that the activation energy of curing reaction is increased as the amount of TBD is increased. EST-5 has an average activation energy of 70.1 kJ/mol, while EST-15 reaches as high as 75.1 kJ/mol. Especially, when the conversion is up to 50%, the activation energy shows an obvious increment. In addition, it has been demonstrated that TBD accelerates the thermal degradation of cured networks at lower temperature and increases the amount of volatiles during thermal decomposition.     

碱水易溶聚酯热降解动力学研究

利用热重分析法(TGA)对自制的碱水易溶聚酯(ASHPET)的热降解动力学进行了研究,并与常规PET和国外某公司碱水易溶聚酯(K-COP)进行了比较。结果表明:几种ASHPET的热稳定性略低于常规PET;三种自制的ASHPET的热稳定性不低于国外某公司的K-COP。     

聚醚的热降解研究进展

介绍了无氧条件下和有氧条件下聚醚的热降解产物,综述了无氧条件下和有氧条件下聚醚结构中聚氧乙烯链节和聚氧丙烯链节的热降解机理和热降解反应路径、影响聚醚热稳定性能的主要因素及聚醚的热降解反应动力学。     

Kinetics of thermal degradation of poly(p‐phenylene benzobisoxazole)

The kinetics of thermal degradation of poly (p-phenylen benzobisoxazole) (PBO) were studied by thermogravimetric analysis (TG) in dynamic nitrogen gas at four different heating rates: 5, 10, 15, 20°C/min. The activation energy calculated by Kissinger Method was 352.19 kJ/mol, and the mean value of activation energies evaluated by Flynn-Wall-Ozawa Method was 338.32 kJ/mol. The degradation kinetic model of PBO followed the mechanism of random scission of weak bonds of PBO molecule and impact of the active groups obtained from the broken bonds, Mampel Power equation with integral form G(α) = α^3/2 and differential form . And the mathematical equation of kinetic compensation effect was ln A = 0.1365 E_a − 1.4102. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3675–3679, 2007     

Low temperature thermal degradation of cellulosic insulating paper in air and transformer oil

The thermal degradation of cellulose in the form of Kraft insulating paper has been studied in air for up to 140 h and in transformer oil for up to 3500 h in the temperature range 60–120 °C using measurements of the degree of polymerization (DP) and (in oil) analysis of furanic degradation products. Degradation was faster in air than in oil. The DP decreased from the original value of 1.2 × 10³ to a limiting value in the range of 300–900 depending on temperature and degradation conditions. The variation of the DP with degradation time was consistent with two mechanisms, one in which the first‐order rate constant decreased exponentially with time, and another in which only a limited number of chain bonds were scissionable. The degradation rate was first order in scissionable bonds. The major furanic degradation products were 2‐furaldehyde, 5‐hydroxymethyl‐2‐furaldehyde and furfuryl alcohol. Their concentrations continually increased over the timescale of the experiments. © 2001 Society of Chemical Industry     

Kinetics of thermal degradation of thermotropic poly(p-oxybenzoate-co-ethylene terephthalate) by single heating rate methods

The kinetics of decomposition of thermotropic liquid crystalline poly(p-oxybenzoate-co-ethylene terephthalate) (poly(B-co-E), BE polymer) with different monomer ratios in both nitrogen and air were studied by dynamic thermogravimetry (TG) from ambient temperature to 800°C. The kinetic parameters, including the activation energy E′, the reaction order n, and the pre-exponential factor Z, of the degradation of the BE polymers were evaluated by the single heating rate methods of Friedman, Freeman–Carroll and Chang. The BE polymers which degraded in two distinct stages in nitrogen and air, were stable under nitrogen, while almost completely burned in air. The weight losses in the first stage in nitrogen and air were dominated by the thermal degradation of both B and E segments, but the weight losses in the second stage were governed by the thermal degradation of B segment in nitrogen and by the oxidative degradation of both B and E segments in air. The maximum rate of weight loss increased linearly with the increase of E content and heating rate, but as E content increased, the char yield at 800°C in nitrogen decreased linearly. The E′, n and ln Z values of the BE polymers in the first stage of thermal pyrolysis are higher in nitrogen than in air, indicating that the degradation rate is slower in an inert atmosphere. The E′ value increased with increasing heating rate but varied irregularly with the variations of B/E ratios and molecular weight. The n and ln Z values for the BE polymers in nitrogen were found to be in the wide ranges 1·5–5·6 and 12–48min^-1, respectively, suggesting a complex degradation process. The estimated lifetimes of the BE polymers at 250°C were calculated to be at least 33 days in nitrogen and 3h in air. © 1998 SCI.     

半芳香聚酰胺热降解性能和非等温结晶动力学研究

在 N2气氛下,用热重分析法研究了半芳香聚酰胺的热降解行为和热降解动力学。并用经 Jeziorny 修正的Arami 方程对其非等温结晶动力学进行了研究。结果表明：半芳香聚酰胺的热降解过程为一步反应,用 Kissinger 方法和Flynn-Wall-Ozawa 方法求得半芳香聚酰胺的热分解活化能分别为258．37 kJ /mol 和227．41 kJ /mol;在非等温条件下,半芳香聚酰胺结晶时可能以片晶形式生长,随着降温速率增大,转变成三维球晶生长。