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。     

DSC法研究UP树脂及增韧剂改性UP树脂的固化行为

通过差示扫描量热（DSC）法确定了不饱和聚酯（UP）树脂采用过氧化二苯甲酰（BPO）、过氧化二异丙苯（DCP）和过氧化二特丁烷（DTBP）3种不同固化剂固化时的最佳固化温度,同时对BPO和DCP体系的固化反应动力学进行了详细研究,包括体系凝胶时间和活化能的确定;研究了液体聚异丁烯（PIB）、马来酸酐接枝PIB（PIB-g-MAH）及甲基丙烯酸缩水甘油酯接枝PIB（PIB—g—GMA）对UP树脂固化行为的影响。     

MAP-POSS改性PMMA非等温聚合反应动力学及物理性能

通过共聚将甲基丙烯酰氧丙基笼型倍半硅氧烷（MAP-POSS）引入到聚甲基丙烯酸甲酯（PMMA）中,制备了有机/无机纳米杂化复合材料。用非等温差示扫描量热法研究了MAP-POSS与MMA共聚反应动力学,测定了反应动力学参数,建立了反应动力学数学模型,并测试了其力学、热学及电学性能。结果表明,MAP-POSS与MMA可以共聚,在不降低电性能的情况下,其冲强度提高了约30 kJ/m2,热分解温度提高了34 ℃。     

光-热双重固化MAP-POSS改性水性环氧树脂/聚氨酯丙烯酸酯涂料的制备与性能

为了使聚氨酯丙烯酸酯(PUA)涂料具有更加优异的性能,本文通过合成二苯基碘鎓盐(DPI·PF6),制备了甲基丙烯酰氧基硅笼(MAP-POSS)改性环氧树脂(ER)/聚氨酯丙烯酸酯(PUA)复合涂料,用二苯基碘鎓盐为光引发剂研究了涂料的光-热混杂固化反应,动态力学和热降解过程。结果表明,涂料有良好的光固化性能,光-热混杂固化可进一步提高材料刚性;紫外光和热固化均可以很好地使体系进行固化成膜反应,并且热固化能提高体系的玻璃化转变温度,使体系的Tg增加50℃左右,当MAP-POSS含量达到12%时,体系的Tg达到最高98.5℃。通过Friedman研究体系的热降解动力学,可以看出在光固化和热固化过程中不同含量的MAP-POSS的加入均随着β的增加Ea明显提高,当MAP-POSS含量达到3%时,Ea值均达到一个高点,但在热固化中,随着反应的进一步进行,在MAP-POSS含量达到12%后,Ea值又继续增加。     

聚氨酯甲基丙烯酸酯树脂的固化行为及填料对其性能的影响

本文研究了UM、UP、VE树脂的固化行为,证实UM比UP和VE树脂具有更高的固化反应活性。并研究了ATH含量对UM树脂性能的影响。     

笼型倍半硅氧烷改性UPR的固化性能与热性能

采用示差扫描量热仪(DSC),热重分析仪(TGA)及动态力学分析仪(DMA)研究了甲基丙烯酰氧丙基笼型倍半硅氧烷(MAP-POSS)与一缩二乙二醇型UPR、苯乙烯的等温共固化反应及动力学,测试了固化物的热性能和动态力学性能。结果表明,固化过程符合自催化反应机理,当体系中MAP-POSS质量分数为5%时,5%热失重温度和残留量5%时的温度较未加体系分别提高7℃和31℃,玻璃化转变温度降低4.2℃,热降解动力学符合1级反应。     

改性双马来酰亚胺树脂的固化特性

本文采用差示扫描量热（DSC）法研究了QYS91—Ⅱ改性双马树脂的固化反应动力学，利用Kissinger方程和Crane方程分别得到了该树脂固化反应表观活化能E、表观频率因子A和反应级数n，进而提出了该树脂固化成型过程的动力学模型，通过固化反应动力学模型对固化反应特性进行了预测，为改性双马树脂实际应用中固化工艺参数的进一步优化提供了一定的理论参考依据。     

UV固化耐热不饱和聚酯树脂的制备与性能研究

设计并制备了可紫外光(UV)固化的耐热双马来酰亚胺(BMD)改性不饱和聚酯(UP)树脂。结果表明,纯BMD不能进行UV固化,但是BMD与UP组成的改性体系可以实现UV固化,并形成交联网络结构。UV固化的BMD改性UP树脂具有优良的热稳定性。     

DSC研究不饱和聚酯/复合引发体系固化反应动力学

本文介绍了不饱和聚酯树脂（UP）常用的几种固化反应动力学模型,实验采用差示扫描量热法（DSC）研究不饱和聚酯/复合引发体系的等温固化反应动力学。选择修正的自催化模型对等温固化DSC数据进行处理,用最小二乘法进行非线性回归,确定等温反应速率常数k0和反应级数m、n,得到动力学方程。研究结果表明不同温度下该模型拟合曲线的相关系数均在98%以上,与实验数据点相吻合,因此所选模型对该体系是适用的,为不饱和聚酯基复合材料的固化研究提供了理论依据。     

改性不饱和聚酯固化反应的研究

本文通过对环氧丙烯酸酸（ＶＥ）树脂改性不饱和聚酯（ＵＰ）树脂的固化过程的研究，制定了合理的树脂蜞体固化制度，并且求解了固化反应的动力学参数。通过对该树脂基体模压料流变性特性的研究，确定了较为合理的模压成型工艺参数。     

Free volume-based modelling of free radical crosslinking polymerisation of unsaturated polyesters

A new mechanistic kinetic model is presented for the cure behaviour of unsaturated polyester (UP) resins. The model is based on free radical polymerisation mechanism and the free volume concept. The quasi steady-state assumption for the free radical concentration is not used, and the decrease in initiator efficiency with conversion and radical trapping are modelled separately. The glass transition temperature of partially cured samples was measured employing differential scanning calorimetry (DSC) in conjunction with dynamic mechanical analysis (DMA), and the values obtained were incorporated into the model. DSC obtained conversion-time data for a standard commercially available UP resin under isothermal conditions. The kinetic parameters of the model were estimated using parameter optimisation procedures resulting in good agreement between model predictions and experimental data. Modelling in combination with experimental cure data showed that at higher isothermal cure temperatures a greater extent of physical trapping of radicals occurs rendering them inactive.     

Properties and Aggregate Structure of Unsaturated Polyester/Phenolic Resin Blends

In this study, unsaturated polyester resin (UP) is blended with resole type phenolic resin, co-crosslinking process performed and the resin blends show miscibility and interpenetration network (IPN) structure. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) are employed to examine the aggregate structure of crosslinked network of the UP/phenolic resin blend. Tensile fractured sections of the resin blends are observed using scanning electronic microscopy (SEM) to shed light on their miscibility. Tensile and flexural tests were also conducted to examine the mechanical properties of the UP/phenolic resin blends. The results show that UP20/Ph80 and UP40/Ph60 resin blends have well-formed Interpenetrating Network (IPN) structures while phase separation is observed for UP60/Ph40 resin blend. Finally, thermal cure of UP80/Ph20 resin blend is incomplete, thus showing immiscibility. The mechanical properties of all resin blends at different mixing proportions deviate from a linear relationship and show a concave curve, indicating the non-additive effect of blending.     

Synthesis and properties of waterborne epoxy acrylate nanocomposite coating modified by MAP-POSS

In this paper, waterborne epoxy acrylate (EA) coating modified with methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS) was prepared. The cure kinetics of the coating was investigated by differential scanning calorimetry (DSC). The curing process, thermal and mechanical properties of the coating were investigated by FTIR, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). These results show that the non-isothermal curing process can be described by Kissinger method and a two-parameter autocatalytic Šesták–Berggren (S–B) model. The kinetic equations of curing reaction were obtained. The UV-curing property of MAP-POSS/EA nanocomposite coating is better than that of pure epoxy acrylate system. The glass transition temperature (T_g) increases with increasing MAP-POSS content. When MAP-POSS content is 12 wt%, the T_g reaches the maximum 54.3 °C which is 9.5 °C higher than that of pure epoxy acrylate.     

沙狐球桌面用不饱和树脂研究

本文叙述不饱和树脂结构设计和固化体系的调整，所研制的不饱和树脂已应用于沙狐球桌面。     

DSC study on simultaneous interpenetrating polymer network formation of epoxy resin and unsaturated polyester

A kinetic study on simultaneous interpenetrating polymer network formation of epoxy resin based on diglycidyl ether of Bisphenol A (DGEBA) and unsaturated polyester (UP) was performed by means of differential scanning calorimetry (DSC). Isothermal DSC characterizations of neat resins and their mixture (in a weight ratio of 50/50) were performed at different temperatures. Dynamic DSC characterization of the systems were performed at three different heating rates. A lower total heat of reaction developed during simultaneous polymerization in dynamic DSC tests was found, compared to the total heats developed during pure resins network formation. This phenomenon can be interpreted as an effect of network interlock that could not be compensated for completely by an increase in curing temperature. The kinetics of the reactions was described by empirical models. The DGEBA, in a 50/50 UP/DGEBA blend, indicated a higher rate constant than the pure DGEBA. The obtained results suggests that the hydroxyl end group of UP in the blend provided a favorably catalytic environment for the DGEBA cure. The results are in good agreement with the literature data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2689–2698, 2002     

Thermal cure behavior of unsaturated polyester/phenol blends

Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used to detect and simulate the cure behavior of unsaturated polyester (UP), phenol, and UP/phenol blends and to calculate and predict the cure rate, cure temperature, conversion, and changes in the glass‐transition temperature along with various cure orders in order to obtain the optimum parameters for processing. With dynamic scanning and isothermal DSC procedures and Borchardt–Daniels dynamic software, cure data for the UP resin were obtained, 90% of the conversion rate at 100°C being achieved after 15 min. However, for the phenol and UP/phenol blends, gradually increasing the temperature was found to be best for curing according to the DSC and DMA test results. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1041–1058, 2004     

Relation between volumetric changes of unsaturated polyester resin and surface finish quality of fiberglass/unsaturated polyester composite panels

Resin dimensional changes, including cure shrinkage and thermal expansion, highly influence the surface finish quality of composite parts. Low profile additives (LPA) are commonly incorporated in unsaturated polyester (UP) resins to compensate for resin shrinkage and obtain a high quality surface finish. In this study, the dimensional change of an UP resin with different LPA contents was characterized. Both resin cure shrinkage and resin thermal expansion were measured. A simple methodology was then developed to estimate the surface finish quality of panels, manufactured by resin transfer molding (RTM), based on the prediction of part thickness variation during the process. Results show good agreement with the experimental investigations. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Effect of dual-initiator on low temperature curing of unsaturated polyester resins

In low temperature composite manufacturing processes, a major concern is how to control the resin gel time and cure time and how to achieve a high resin conversion with low residual volatile organic chemicals. In this study, a cobalt promoter catalyzed dual-initiator system was used to control the reaction rate and resin conversion of unsaturated polyester resins. A mechanistic kinetic model was developed to predict the reaction kinetics with dual initiators. This model can be used to simulate the isothermal and dynamic reaction rate and conversion profiles. It can also be utilized to predict the effect of promoter concentration on UP resin cured at low temperatures. The dual-initiator system was applied in the vacuum-assisted resin transfer molding process at room temperature. The kinetic model, in conjunction with the heat transfer analysis, was able to successfully predict the temperature profiles during the molding processes.     

Reaction kinetics and physical properties of unsaturated polyester modified with methylacyloxylpropyl-POSS

The polyhedral oligomeric silsesquioxanes which contains methylacryloylpropyl group (MAP-POSS) was synthesized and used to modify unsaturated polyester resin (UPR). The cure kinetics was investigated by isothermal DSC technique. The mechanical and electrical properties of fiberglass-reinforced laminate were determined. The result shows that the reaction can be described by a Kamal autocatalytic model which has two reaction rate constants k ₁ and k ₂, and two apparent activation energies E _a1 and E _{a 2} are 98.12 kJ/mol and 74.01 kJ/mol, respectively. UPR and MAP-POSS can co-cure in free radical polymerization. When the MAP-POSS content is 5 wt%, the impact and tensile strength of fiberglass-reinforced laminate enhanced 10% and 6%, respectively, and has better electrical properties than no MAP-POSS. The dielectric constant ε and dielectric loss tanδ are all decrease. The surface resistance ρ _s is 4.7 times higher than pure UPR laminates     

UV-Curable Coating of Unsaturated Polyester/Epoxy Resins Containing Polyhedral Oligomeric Silsesquioxanes

UV-curable coating of unsaturated polyester/epoxy resin (UP-ER) modified with methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS) was prepared. The UV-cured process, kinetics, and some properties of coating were investigated. The results show that this coating has a better UV-curing property. The curing reaction can be described by a two-parameter autocatalytic ?esták-Berggren (S-B) model. The mechanical loss peak temperature T _p of curing coating nanocomposites increased with increasing MAP-POSS content and has a highest value when MAP-POSS content is 12%, which is 121.8°C, and higher, about 18.3°C, than a pure UP-ER system. The coating film has lower volume shrinkage than pure UP-ER.