低温固化型混合型粉末涂料用聚酯树脂固化动力学研究

用差示扫描量热法(DSC)对混合型聚酯树脂进行固化动力学研究,确定了该体系的特征参数:起始固化温度(T0)、恒温固化温度(Tp)和后处理温度(Tf)分别为68℃、143℃、168℃。同时通过Kissinger以及Crane方程计算出该体系的固化反应表观活化能E为76.19 kJ/mol、反应级数n为0.913,指前因子A为4.35×108,确定了该体系的固化动力学方程。通过等温固化对该体系的研究得到了不同固化温度下转化率变化曲线,用非等温固化研究得到的动力学方程与等温固化得到的曲线进行比较研究,为优化混合型粉末涂料固化工艺提供了理论依据。     

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。     

DSC法研究不饱和聚酯树脂的固化反应动力学及其固化过程

采用示差扫描量热法（DSC）分别研究了Ashland UP（R36）以及DSMUP（972B）这两种不饱和聚酯树脂（UP）的固化过程,并利用了KiSSinger方程、Crane经验方程等分析了这两种树脂的固化反应,得到了其固化反应的表观活化能、Arrhenius指前因子（频率因子）、反应级数等动力学参数,最后利用Y—B外推法确定了这两种不同树脂的凝胶温度、固化温度和后固化温度等固化工艺温度。     

低温固化环氧粉末涂料制备及性能研究

通过转矩流变仪用E-12型环氧树脂和TC-125固化剂及其他助剂在90℃下熔融混合10min,然后在平板硫化机上冷压3min,最后经过球磨机粉碎制得环氧粉末涂料。制得的粉末涂料和漆膜经过差示扫描量热法和红外光谱分析．并讨论了固化剂用量、升温速率等对涂料性能的影响。结果表明：该粉末涂料可实现低温固化,固化条件为120℃下恒温固化35min;固化剂用量为28％时,涂膜的各项物理性能良好。     

低温固化环氧树脂粉末涂料的制备及性能研究

通过双螺杆挤出机用E-12型环氧树脂和YLT-118固化剂及其他助剂在90℃下熔融混合10 min,然后在平板硫化机上冷压3 min,最后经过粉碎机粉碎,过筛制得环氧粉末涂料。采用差示扫描量热法和红外光谱表征粉末涂料,并讨论了填颜料用量、固化条件等对涂料性能的影响。结果表明：该粉末涂料可实现低温固化,固化条件为120℃下恒温固化30 min;固化剂用量为环氧树脂的16.7%时,m（环氧树脂）∶m（填颜料）为150∶135时,得到的涂膜各项物理性能最好。     

不饱和聚酯树脂固化特性的研究

采用推广放热曲线法(SPI)和差示扫描量热法(DSC)研究了不饱和聚酯树脂(UPR)的固化反应历程,讨论引发剂对UPR体系固化特性的影响,并由DSC曲线得到固化工艺和动力学参数。结果表明:引发剂对固化特性的影响很大,其用量宜为UPR的1％-2％;引发剂含量2％时,确定UPR固化温度为120℃,后处理温度为140℃,表观活化能74．3 kJ／mol,碰撞因子1．71×10 9。反应级数O．916;等温固化时,当反应程度超过0．7,固化反应由动力学控制阶段转向扩散控制阶段。     

铝型材粉末涂料静电喷涂固化工艺过程的分析

用差示扫描量热法(DSC)对聚酯/TGIC铝型材专用粉末涂料的非等温固化反应进行了研究,分析了粉末涂料固化反应过程,采用温度-升温速率图外推法确定了该体系的特征参数凝胶温度(To)、固化温度(Tp)和后处理温度(Tf)分别为122℃、150℃、206℃;通过DSC测试分析,确定了该体系粉末涂料的最低固化温度为120℃左右,静电喷涂较佳的固化工艺参数为200℃/20 min,为铝型材粉末涂料静电喷涂固化工艺过程控制的确定提供了重要的参考依据。     

不饱和聚酯树脂固化动力学研究进展

介绍了不饱和聚酯树脂(UPR)固化反应动力学的n级反应模型和自催化模型,指前因子(A)和表观活化能(E)的求解方法:Kissinger法,Ozawa法和Friedman法以及由Crane方程或形状指数Si求解反应级数(n)的方法,综述了目前国内外DSC法研究UPR固化动力学的进展。     

聚氨酯胶粘剂的固化反应及动力学研究

以多苯基多亚甲基多异氰酸酯(PAPI)和硅氢封端有机硅树脂(PDMS)为主要原料,制备了一种可在室温下固化的含碳硼烷耐高低温胶粘剂用树脂。通过差示扫描量热法(DSC)研究其固化反应中的各个固化特征,并且分别采用了Kissinger法和Ozawa法计算该反应的反应活化能、反应级数和频率因子等动力学参数。研究结果表明:由两种方法计算所得的表观活化能分别为32.9和36.9 kJ/mol,固化反应级数分别为0.86和0.95,接近一级反应。     

柔性UPR树脂/粉煤灰非等温固化动力学

用差示扫描量热法(DSC)研究了柔性不饱和聚酯树脂/粉煤灰体系的非等温固化过程,利用T-β外推法确定了体系的固化工艺温度:凝胶温度257.625K、固化温度374.275K、后处理温度406.565K。用Flynn-Wall-Ozawa法和Friedman-Reich-Levi法获得了柔性UPR固化反应表观活化能为Ea=83.94kJ·mol-1。由ASTME698-79标准方法求得指前因子,lnA=25.27;结合Crane方程分析知,复合体系的固化反应接近于一级反应。最终建立了复合体系固化反应动力学方程为ln(ddαt)=25.27-10096.22T+ln(1-α)0.9126。     

Curing kinetics of medium reactive unsaturated polyester resin used for liquid composite molding process

The cure kinetics of medium reactivity unsaturated polyester resin formulated for Liquid Composite Molding process simulation was studied by Differential Scanning Calorimetry (DSC) under isothermal conditions over a specific range of temperature. For isothermal curing reactions performed at 100, 110, and 120°C, several influencing factors were evaluated using the heat evolution behavior of curing process. We propose two‐ and three‐parameter kinetic models to describe the cure kinetics of thermoset resins. Comparisons of the model solutions with our experimental data showed that the three‐parameter model was the lowest parameter model capable of capturing both the degree of cure and the curing rate qualitatively and quantitatively. The model parameters were evaluated by a non‐linear multiple regression method and the temperature dependence of the kinetic rate constants thus obtained has been determined by fitting to the Arrhenius equation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

二恶唑啉改性酚醛树脂固化动力学研究

采用非等温差示扫描量热(DSC)法探讨了固化剂为六次甲基四胺的酚醛树脂(PF2828)和二恶唑啉(1,3–PBO)固化酚醛树脂(PF)(1,3–PBO 与 PF 质量比为40∶60)在不同量α,α–二溴对二甲苯(质量份数分别为0.5份,1.5份)作用下的固化行为,运用 Kissinger 法和 Ozawa 方法对其固化动力学进行研究,得到了固化反应活化能。结果表明,二恶唑啉和催化剂α,α–二溴对二甲苯的使用,可以加速 PF 的固化反应,降低了 PF 固化反应的活化能;当催化剂用量为1.5份时,最易于改性 PF 固化反应的进行。     

非等温DSC法研究环氧树脂固化反应动力学过程

采用非等温DSC(差示扫描量热)法研究了环氧树脂(EP)体系的固化过程,并采用Kissinger方程、Crane方程和T-β(温度-升温速率)外推法计算出该EP体系固化反应的动力学参数和固化温度。研究结果表明:当m(EP)∶m(填料)∶m(固化剂)∶m(促进剂)=100∶30∶90∶0.4时,EP体系固化反应的表观活化能为78.90 kJ/mol、指前因子为2.58×109min-1和反应级数为0.914,其最佳固化条件为"从室温升温至92℃(开始凝胶)→继续升温至140℃(恒温固化)→最后升温至169℃(进行后固化处理)"。     

Viscosity modeling of a medium reactive unsaturated polyester resin used for liquid composite molding process

The development of new composite product for an application through liquid composite molding (LCM) process simulation requires submodels describing the raw material characteristics. The viscosity during resin cure is the major submodel required for the effective simulation of mold-filling phase of LCM process. The viscosity of the resin system during mold filling changes as the cure reaction progresses. Applied process temperature also affects the viscosity of the resin system. Hence, a submodel describing the resin viscosity as a function of extent of cure and process temperature is required for the LCM process simulation. In this study, a correlation for viscosity during curing of medium reactive unsaturated polyester resin, which is mostly used for the LCM process, has been proposed as a function of temperature and degree of cure. The viscosity and the degree of cure of reacting resin system at different temperatures were measured by performing isothermal rheological and isothermal differential scanning calorimetry experiments, respectively. A nonlinear-regression analysis of viscosity and degree of cure data were performed to quantify the dependence of viscosity on temperature and extent of cure reaction. Comparisons of model solutions with our experimental data showed that the proposed empirical model is capable of capturing resin viscosity as a function of extent of cure and temperature qualitatively as well as quantitatively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

没食子酸环氧树脂/蓖麻油酸多胺体系固化动力学及性能

以蓖麻油和三乙烯四胺为原料合成蓖麻油酸多胺固化剂(COAPA),再将其与没食子酸环氧树脂(GAER)混合组成全生物基GAER/COAPA固化体系,采用非等温差示扫描量热法(DSC)对其固化反应过程进行了研究,确定了固化体系最佳质量配比为7:3(GAER:COAPA),获得了最佳固化工艺温度参数;利用Kissinger方...     

Thermochemical and isoconversional kinetic analysis of a polyester–epoxy hybrid powder coating resin for wood based panel finishing

Powder coating is an established technology especially for the surface finishing of metallic substrates for example in the automotive industry. Moreover, powder technology holds also great promises for the coating of non-conventional substrates like plastics or wood due to the lack of solvents and good recoverability. Here, low-temperature curing resins are required and especially mild processing conditions are demanded by the substrates. Advanced characterization methods need to be established that allow the precise balancing of the processing conditions required for adequate melting, flowing and curing of the powder with the process conditions that can be tolerated by the temperature-sensitive substrates. In the present contribution it is shown that differential scanning calorimetry (DSC) in combination with isoconversional kinetic analysis (ICKA) provides great potential for this purpose. DSC is a standard thermo-chemical method that can be successfully used to study both the melting and curing processes of powder coatings and to determine, for example the glass transition temperature of the cured coating directly from the measured thermograms. However, still more information can be extracted from the enthalpy signals when more sophisticated methods of data post-treatment and analysis are employed. Isoconversional kinetic analysis techniques such as the Kissinger–Akahira–Sunose (KAS) or the advanced Vyazovkin (VA) approaches allow calculating the time-dependencies of physical and chemical processes at various temperatures based on the estimates of activation energies which are obtained from DSC raw data. These analyses allow for example to calculate the time required for a certain degree of cross-linking in the coating after processing the coating under specified curing conditions. In the present contribution the application of ICKA of DSC measurements for the analysis of the flowing and curing behaviour of a powder coating based on a polyester–epoxy hybrid resin is illustrated and the potential of this approach to predict optimal curing times for arbitrary curing temperatures is demonstrated. This is especially useful when temperature-sensitive substrates like wood-based panels are coated. Additionally, the potential to relate the thermo-chemical properties of the powder coating to the surface properties of the coated substrates is discussed.