用烯丙基醚的不饱和聚酯

鉴于不饱和聚酯具有极佳的性能(快速固化,极佳的抗化学性及抗沾污性,高光泽及厚膜,是用于木器涂料最重要的树脂之一。Kent Sorensen在本文的第一部份阐述了如何用三羟甲基丙烷单烯丙基醚(TMPME)来配制及生产不饱和聚酯,在第二部份阐述了固化动力学及某些配方的性能。     

烯丙基醚改性不饱和聚酯的合成

用对苯二甲酸二甲酯、丙二醇、马来酸酐以及三羟甲基丙烷二烯丙基醚合成了空干性不饱和聚酯 ,探讨了合成反应的条件 ,并与邻苯型、间苯型树脂作比较。     

双马来酰亚胺／不饱和聚酯的共聚改性研究

利用4，4^ -二苯甲烷型双马来酰亚胺(BMD)作为共聚单体与不饱和聚酯(UP)进行共聚改性，对这一共聚体系的性能进行了研究：研究结果表明：双马来酰亚胺的引入对UP树脂的力学性能造成一定影响，尤其显著提高了共聚物热分解温度和热变形温度。从BMD的分子结构来看，BMD是四官能度，而且BMD具有优先与苯乙烯反应生成交替共聚物的倾向，提高了网络交联密度，在宏观上表现为共聚物的热性能及力学性能的变化。另外，红外光谱的分析表明双马来酰亚胺与不饱和聚酯固化形成交联网络。     

不饱和聚酯树脂的阻燃改性研究

本文用适量的阻燃剂对不饱和聚酯树脂（UP）进行改性，确定了优化的配方和工艺流程，使产品具有良好的阻燃性能（氧指数越过31％）、力学性能（抗拉伸强度没有明显降低），该项研究拓宽了不饱和聚酯树脂的应用领域。     

聚氨酯改性不饱和聚酯木器底漆的研究

为了提高不饱和聚酯木器底漆的低温打磨性,采用聚氨酯对不饱和聚酯进行改性,形成互穿聚合物网络(IPN)结构,通过IPN协同效应,结合聚氨酯涂料和不饱和聚酯涂料的优点,获得干燥速度快,易打磨,性能优异的漆膜,聚氨酯用量为30%～50%时效果最佳。     

191型不饱和聚酯用作原子灰的研究

研究了一种高分子增塑剂,用它改善了１９１型不饱和聚酯树脂（ＵＰＲ）的柔韧性和耐寒性,使之适用于制作原子灰和嵌填材料,并推出了合适的成分配比。     

聚氨酯改性不饱和聚酯的徽观结构与性能

利用与天然纤维具有良好亲和性的聚酯聚氨酯(PU)改性不饱和聚酯(UP),通过扫描电镜（SEM）、傅里叶红外光谱（FT-IR）、接触角和力学性能等,研究了改性不饱和聚酯的微观结构、反应程度和主要性能.研究结果表明,引入PU提高了不饱和聚酯树脂的韧性,增加了与天然纤维的界面浸润性,降低了不饱和聚酯树脂的固化收缩率.所得改性不饱和聚酯的冲击断裂截面表现为韧性断裂;与天然纤维的接触角随着聚氨酯添加量的增加而降低,表明改性不饱和聚酯与天然纤维的浸润性增强.力学性能测试表明,当PU含量为5%时,其冲击强度可提高80%,弯曲模量降低小于20%,固化收缩率低于4%.     

高黏度不饱和聚酯树脂的合成研究

以邻苯二甲酸酐、顺丁烯二酸酐和丙二醇为原料合成了一类可用于SMC(片状模塑料)和BMC(团状模塑料)的高黏度不饱和聚酯树脂。并对其原料配比、阻聚剂用量、温度﹑搅拌速度和惰性气体流量等对合成工艺的影响进行了研究。     

气干性不饱和聚酯树脂的合成及其性能

讨论了阻聚剂(对苯二酚)的用量对不饱和聚酯树脂凝胶时间及贮存期的影响;同时使用了烯丙基醚基团(CH2=CH—CH2—O—)作为气干性基团,对传统不饱和聚酯树脂进行改性,讨论了烯丙基醚用量对不饱和聚酯树脂气干性的影响。实验结果表明,最佳对苯二酚用量为0 016%,烯丙基醚用量>20%。     

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.     

Dynamic mechanical analysis of segmental relaxation in unsaturated polyester resin networks: Effect of styrene content

The effect of styrene content on non-exponential and non-Arrhenius behavior of the α-relaxation of cured unsaturated polyester resins (UPR) was investigated by dynamic mechanical analysis (DMA). To compare the temperature dependence of the relaxation times, the Angell fragility concept was applied to samples with different crosslink densities. Furthermore, the number of structural units per cooperatively rearranging region (CRR) was estimated using random walk model and the modified Adam-Gibbs theory. The results showed that rising styrene content enhanced the crosslink density of the networks, which altered the intensity and broadness of the α-relaxation. The fragility index, a measure of temperature dependence of relaxation time, and the average size of CRR at glass transition region was also increased by styrene content. Therefore, the segmental relaxation in networks with higher crosslink density could be associated with stronger intermolecular coupling. In addition, it was observed that the mean required energy for internal rearrangement of structural units within the CRR decreased as the fragility index increased, while the mean barrier height for repositioning of a CRR in cooperation to its local environment was nearly constant.     

Kinetics of polyesterification: modelling and simulation of unsaturated polyester synthesis involving 2-methyl-1,3-propanediol

The kinetics of the individual key reactions involved in the formation of unsaturated polyester resins have been studied using the very reactive glycol, 2-methyl-1,3-propanediol (MPD). This diol has been reacted in turn with maleic anhydride (MA), phthalic anhydride (PA) and isophthalic acid (IA) under isothermal conditions in the temperature range 180-210 °C and the kinetic constants for the following reactions have been obtained MA+MPD, PA+MPD, IA+MPD, MA+PA+MPD and MA+IA+MPD. The relative reactivities of MPD with MA and PA measured by monitoring the loss of carboxyl groups at 180 and 200 °C were found to be 2.26 and 1.70, respectively. At 200 °C PA is more reactive than IA (ratio approximately 1.31) in homopolyesterification. In the copolyesterifications involving PA and IA where cross catalysis can occur, the PA reacted approximately 1.25 times faster than IA at 200 °C. The differences in reactivity might be expected to have a significant effect on the coreactant sequence lengths in prepolymers formed by the concurrent reaction of PA, IA and MPD particularly at low conversions thus on the final properties of the cured resins in which they are employed. The properties of the products are not examined in this paper.     

Curing reaction of unsaturated polyester resin modified by dicyclopentadiene

The objective of this research is to prepare modified unsaturated polyester resin(UPR) with good processibility, dimension stability and mechanical properties. In this study, dicyclopentadiene (DCPD) is selected as a modifier and the effect of DCPD content on the curing behavior of the modified UPR is examined via Differential Scanning Calorimetry (DSC) and Rheometrics Dynamic Analysis (RDA) experiments. The results of ¹H NMR identification for the chemical structure of modified UPR show that the trans-structure of UPR decreases as the DCPD content increases. The curing time necessary to reach peak maximum in DSC during the curing reaction lengthens as the stereo obstacles formed by the binary rings increase.     

Effect of nanoclay on shrinkage control of low profile unsaturated polyester (UP) resin cured at room temperature

The addition of a small amount of nanoclay (1-3 wt%) can provide excellent volume shrinkage control of unsaturated polyester (UP)/styrene (St)/poly(vinyl acetate) (PVAc) systems cured at room temperature. PVAc serves as the low profile additive (LPA). In this study, both temperature-induced phase separation of the uncured resin mixture and transmission electron microscopy (TEM) of the cured sample revealed that nanoclay resided in the LPA-rich phase, leading to a higher reaction rate and earlier onset of micro-cracking in the LPA-rich phase or at the interface of the LPA-rich and UP-rich phases. Consequently, an earlier volume expansion during curing was observed in reactive dilatometry, resulting in better shrinkage control. On-line measurement of the composite thickness change during vacuum-infusion liquid composite molding [e.g. the Seemann Composite Resin Infusion Molding Process (SCRIMP)] further proved excellent volume shrinkage control of nanoclay filled systems, leading to a smoother composite surface.     

聚酯下脚料生产对苯二甲酸型不饱和聚酯的研究

研究了利用聚酯下脚料生产对苯二甲酸型不饱和聚酯树脂的方法。分析了原料配比及工艺参数对产品性能的影响,将对苯二甲酸型不饱和聚酯的性能与邻苯二甲酸型不饱和聚酯及间苯二甲酸型聚酯的性能进行了比较。结论认为对苯二甲酸型不饱和聚酯树脂是一种性能良好的耐腐蚀树脂。     

对苯型不饱和聚酯树脂性能的研究

研究了以聚酯回收料为原料生产的对苯型不饱和聚酯树脂的固化性能和耐化学腐蚀性能,分析了影响凝胶时间的各种因素。试验结果表明,所得对苯型树脂具有优良的耐化学腐蚀性能。其耐酸性、耐碱性、耐盐性和耐水性能与间苯UPR树脂相当,其耐溶剂和耐氧化酸性能与双酚A型UPR树脂相当。     

Control of shrinkage and residual styrene of unsaturated polyester resins cured at low temperatures: I. Effect of curing agents

In low temperature molding processes, control of resin shrinkage and residual monomer is an important concern. The presence of low profile additives (LPAs) can reduce the shrinkage of unsaturated polyester (UP)/styrene (St) resins under proper processing conditions but may increase the residual styrene content. A systematic study was carried out to investigate the effect of the initiator system and reaction temperature on sample morphology, final resin conversion, and resin shrinkage of UP resins with LPA. It was found that the final conversion of the resin system could be improved by using dual initiators. The effect is more obvious at low temperatures. Volume shrinkage measurements of the resin system initiated with dual initiators revealed that good LPA performance was achieved at low (e.g. 35 °C) and high (e.g. 100 °C) temperatures but not at intermediate ones. This can be explained by how temperature affects phase separation, reaction kinetics in the LPA-rich and UP-rich phases, micro-void formation, and thermal expansion.