5405双马来酰亚胺树脂动态固化反应动力学研究

采用差示扫描量热(DSC)法对5405 BMI树脂的固化反应动力学进行研究。利用Kissinger方程和Crane方程分别得出不同升温速率下的非等温固化反应表观活化能(Ea)63.438 k J/mol,表观频率因子(A)2.25×104 S-1及反应级数(n)0.844。以自催化反应动力学模型为基础,建立了5405 BM I树脂的动态固化反应动力学方程。同时采用反应温度-升温速率外推法,获得了5405 BMI树脂的固化反应特征温度,凝胶化温度(Tgel.)153.2℃,固化温度(Tcur.)195.8℃,后处理温度(Ttre.)258.2℃。为优化树脂在实际应用中的固化工艺提供了一定的理论参考数据。     

大型风机叶片用环氧树脂固化动力学研究

本文对目前国内大型风机叶片生产中使用量较大的树脂体系固化反应动力学进行了研究,根据不同升温速率下的非等温DSC曲线,依照Kissinger方程和Crane方程,分别计算了反应活化能和反应级数、指前因子。计算结果显示,RIM135/RIM137H树脂体系的表观活化能是51.48 kJ/mol,反应级数为0.886 3。同时,给出了该树脂体系的固化参考工艺温度和固化动力学模型。     

热固性SMC固化动力学研究

本论文借助差示扫描量热仪测得热固性SMC树脂基体在不同升温速率下发生反应的起始温度T_i,峰值放热温度T_P,和固化反应终止温度T_f;利用所得数据和Kissinger方程可得出热固性SMC的反应活化能E_a,已知E_a的前提下,利用Crane可计算得到反应级数n,并确定了固化反应的频率因子A和峰温时的反应速率常数K_p等固化动力学参数;借助不同升温速率下热固性SMC不同的峰值温度,采用外推法确定了热固性SMC的固化工艺。     

非等温DSC法研究非异氰酸酯聚氨酯的固化反应动力学

利用非等温差示扫描量热法(DSC)研究了不同升温速率下非异氰酸酯聚氨酯(NIPU)的固化反应过程,通过模拟n级反应动力学模型,采用Kissinger方程、Crane方程以及特征温度-升温速率外推法计算出该固化体系的动力学参数以及最佳固化温度。研究结果表明,该体系的凝胶温度为100℃,固化温度为176℃,后固化温度为234℃,固化时间为17min。     

聚酯树脂粉末涂料的固化行为

用差示扫描量热法(DSC)对固态条件下聚酯/TGIC(triglycidyl isocyanurate)体系的非等温固化反应动力学进行了研究。根据DSC和热重（TG）的分析结果,对聚酯粉末的固化过程及热稳定性进行了探讨,通过温度-升温速率图外推法确定了该体系的凝胶温度、固化温度和后固化温度分别为113、146和195℃。采用Kissinger方程、Doyle-Ozawa方程和Crane方程对DSC数据进行分析,得到了固化反应的平均表观活化能65.71 kJ·mol^-1,频率因子8.50×106 min^-1、反应级数0.95,建立了该树脂体系的固化动力学模型。讨论了固化反应速率、固化度、固化温度与时间等关系的变化规律及影响因素,为优化铝型材用粉末涂料聚酯体系的固化工艺提供了理论基础。     

钢质管道防腐用熔结环氧粉末固化反应特性

采用示差扫描量热法(DSC)在动态条件下研究了钢质管道防腐用熔结环氧粉末的反应特性,根据不同升温速率下测得的动态DSC曲线图谱,运用温度-升温速率(T-β)图外推法获得了基础的固化工艺参数,即凝胶温度(Tg)92.76℃、固化温度(Tc)133.94℃和后处理温度(Tt)160.58℃。并采用Kissinger方程和Crane公式计算确定了体系的固化反应动力学模型方程式,在此基础上,预测了等温条件下该种管道用熔结环氧粉末涂料的固化反应特性,对今后的管道防腐涂层施工提供了理论参考。     

基于高比例尿素改性PF树脂的固化特性及动力学研究

为探讨高比例尿素改性PF(酚醛树脂)的固化特性,采用差示扫描量热分析(DSC)方法,对不同升温速率条件下树脂的固化过程、特征放热峰温度等进行了检测分析;通过Kissinger和Ozawa方法,计算了固化反应表观活化能,建立了固化反应动力学模型。研究结果表明:高比例尿素改性PF树脂的固化反应活化能较低,反应易于进行,固化温度为131.3℃,较普通PF树脂降低了近20℃。     

高固含量聚醚醚酮改性酚醛树脂固化动力学研究

采用溶液聚合法合成了高固含量(>80%)聚醚醚酮(PEEK)改性酚醛树脂(PF),用非等温DSC(差示扫描量热)法和T-β(温度-升温速率)外推法对其固化反应动力学过程进行了研究,并根据Kissinger方程、Ozawa方程和Crane方程等计算出该固化反应的动力学参数。结果表明:改性树脂的凝胶化温度为136.68℃,固化温度为167.16℃,后处理温度为197.39℃;其固化体系的表观活化能为100.02 kJ/mol,频率因子为1.84×106 s-1,反应级数为0.94(近似于1级反应)。     

CE2908聚酯粉末涂料固化反应特性

用示差扫描量热法(DSC)在动态条件下对CE2908聚酯/异氰尿酸三缩水甘油酯(TGIC)体系的固化反应动力学进行了研究。运用温度-升温速率图外推法确定了该体系的特征参数∶凝胶温度(T0)、固化温度(Tp)和后固化温度(Tf)分别为113℃、146℃和195℃。采用Kissinger方程和Crane方程计算CE2908聚酯/TGIC酯体系的动力学参数,平均表观活化能Ea为62.32 kJ/mol、频率因子A为8.50×106min-1、反应级数n为0.95。建立了该树脂体系的固化动力学模型。利用所建立的固化动力学方程分别讨论了等温和动态条件下CE2908聚酯/TGIC的固化反应特性,为优化聚酯/TGIC体系粉末涂料固化工艺提供了理论依据,并在生产工艺中验证了其正确性。     

间苯二甲酸二缩水甘油酯固化动力学的研究

以DSC为主要测试手段,对间苯二甲酸二缩水甘油酯(DGPA)的不同固化体系进行了研究,得出了固化曲线,并根据经验公式求出了DGPA的固化动力学参数。结果表明,DGPA树脂因固化剂不同,固化动力学参数存在较大差异,其固化活性低于DER331树脂;此外,对于不同固化体系,不同升温速率下,固化剂活性对固化物玻璃化温度影响较大,固化剂活性越高,玻璃化温度越低。     

环氧树脂固化动力学的非等温DSC研究

用非等温DSC对环氧树脂在动态升温过程中的固化动力学进行了研究,采用Kissinger方程对固化动力学模型参数中固化反应活化能、反应级数和指前因子进行了计算,并用Ozawa法对固化反应活化能进行了验证,计算结果表明,EP/DDS固化反应符合n阶固化动力学模型,结合不同升温速率下的特征温度,对环氧树脂的固化条件进行了优化。     

腰果酚缩醛胺与环氧树脂的固化反应动力学的研究

在不同升温速率下,用差示扫描量热分析(DSC)研究了腰果酚缩醛胺固化剂(PCD)与环氧树脂的固化反应动力学。通过Kissinger、Crane方程和等转化率的方法求得了其表观活化能E=39.89kJ/mol,固化反应级数n=0.906。     

不饱和聚酯/复合引发体系非等温固化动力学研究

采用非等温DSC法研究了不饱和聚酯/复合引发体系在不同升温速率下的固化行为,通过T-Φ外推法确定了该体系的凝胶温度、固化温度和后固化温度分别为102.7℃,124.0℃和196.5℃。通过Kissinger和Crane方程对DSC数据进行处理,获得了固化反应的表观活化能E=116.88 kJ/mol,碰撞因子A=7.35×1014,反应级数n=0.945,并由此得到了该体系的固化动力学方程。     

Cure kinetics of a glass/epoxy prepreg by dynamic differential scanning calorimetry

Dicyandiamide (DICY)‐cured epoxy resins are important materials for structural adhesives and matrix resins for fiber‐reinforced prepregs. Dynamic differential scanning calorimetry (DSC) with heating rates of 2.5, 5, 10, and 15°C/min was used to study the curing behavior of the epoxy prepreg Hexply 1454 system, which consisted of diglycidyl ether of bisphenol A, DICY, and Urone reinforced by glass fibers. The curing kinetic parameters were determined with three different methods and compared. These were the Kissinger, Ozawa, and Borchardt–Daniels kinetic approaches. The lowest activation energy (76.8 kJ/mol) was obtained with the Kissinger method, whereas the highest value (87.9 kJ/mol) was obtained with the Borchardt–Daniels approach. The average pre‐exponential factor varied from 0.0947 × 10⁹ to 2.60 × 10⁹ s⁻¹. The orders of the cure reaction changed little with the heating rate, so the effect of the heating rate on the reaction order was not significant. It was interesting that the overall reaction order obtained from all three methods was nearly constant (≅2.4). There was good agreement between all of the methods with the experimental data. However, the best agreement with the experimental data was seen with the Ozawa kinetic parameters, and the most deviation was seen with the Borchardt kinetic parameters. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polymerization of diglycidyl ether of bisphenol A/ diaminodiphenyl sulfone epoxy resins using radio frequency fields

Curing of diglycidyl ether of bisphenol A/diaminodiphenyl sulfone (DGEBA/DDS) epoxy resin has been effected by heating with radio frequency (RF) radiation at frequencies of 30–99 MHz. The epoxy resins can be cured rapidly at low RF power levels. Comparison of the kinetics of the RF curing with thermal curing while maintaining the same curing temperature revealed no differences. Previous differences in rates of thermal and microwave curing are believed to be due to lack of temperature control during microwave curing. For RF curing, the rate of cure, at constant power level, increases at lower RF frequency, thus emphasizing one of the principal advantages of RF curing over microwave curing. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2917–2923, 1999     

聚氨酯柔性固化剂/环氧体系固化动力学及机理

通过不同升温速率下示差扫描量热分析(DSC)研究了自制的聚氨酯柔性固化剂ATPU/环氧树脂E-44体系的固化反应动力学及机理。通过Kissinger和Crane方程求解了表观活化能和反应级数等动力学参数,并运用该参数研究了固化反应速率常数、固化反应速率、固化度等的变化规律及影响因素。通过反应级数的研究证明了固化反应为一复杂反应,不同的固化交联反应同时发生,但主要进行的是伯氨基及仲氨基与环氧基之间的反应,该类反应使得体系得以固化。     

Equivalent processing time analysis of glass transition development in epoxy/carbon fiber composite systems

The cure kinetics and glass transition development of a commercially available epoxy/carbon fiber prepreg system, DMS 2224 (Hexel F584), was investigated by isothermal and dynamic‐heating experiments. The curing kinetics of the model prepreg system exhibited a limited degree of cure as a function of isothermal curing temperatures seemingly due to the rate‐determining diffusion of growing polymer chains. Incorporating the obtained maximum degree of cure to the kinetic model development, the developed kinetic equation accurately described both isothermal and dynamic‐heating behavior of the model prepreg system. The glass transition temperature was also described by a modified DiBeneditto equation as a function of degree of cure. Finally, the equivalent processing time (EPT) was used to investigate the development of glass transition temperature for various curing conditions envisioning the internal stress buildup during curing and cooling stages of epoxy‐based composite processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 144–154, 2002; DOI 10.1002/app.10282     

Nonisothermal curing kinetics of a novel polymer containing phenylsilylene and propargyl–hexafluorobisphenol a units

A novel thermosetting polymer, poly[(phenylsilylene) propargyl–hexafluorobisphenol A] (PBAFS), with a new structure was synthesized. The structure of PBAFS and its cured resins were characterized by Fourier transform infrared spectra. During curing, a hydrosilylation reaction may occur between Si? H and C?C bonds and a Claisen rearrangement reaction of aryl propargyl ether led to formation of chromene, which immediately preceded polymerization on heating. The dynamic viscosity behavior was investigated by rheological experiment. Thermal stability of the cured PBAFS was also measured by Thermogravimetric analysis. The curing behavior of PBAFS was monitored by nonisothermal differential scanning calorimetry at different heating rates. The kinetic parameters and the kinetic model of the cure reaction were evaluated by Kissinger, Ozawa, and Friedman methods. The cure reaction of PBAFS was found nth‐order in nature and the prediction curves by Friedman method for nonisothermal curing reaction were in good agreement with the experimental curves. The isothermal curing time of PBAFS were predicted by Vyazovkin and model‐fitting methods from the nonisothermal kinetic parameters. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Analysis of the heat-release mechanism during thermal stabilization of polyacrylonitrile fiber rope

Results of experimental studies of heat release during heating of polyacrylonitrile (PAN) rope are presented. The heating conditions for PAN rope samples of elemental fiber linear density 0.08, 0.10, and 0.12 tex to 330°C at rates 2, 3.5, and 5 K/min were selected to model thermal stabilization processes in an oxidation furnace. These data were used to determine the kinetic constants in the Arrhenius equation using the method proposed by L. I. Volkova. Experimental heat release in rope as a function of time at various heating rates was used to determine the kinetic reaction constants. Kinetic constants of the generalized reaction were determined for all tested ropes and conditions. A heat-release equation was formulated based on the kinetic constants for each PAN rope sample. The rope mass change as a function of time M(t) expressed in fractions and represented as a second-order polynomial was determined from the rope mass loss at heating rate 3.5 K/min.