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%.     

Synthesis and properties of a modified unsaturated polyester resin with phosphorus-containing pendant groups

A novel modified-unsaturated polyester resin (M-UPR) with phosphorus-containing pendant groups was successfully prepared by employing a bifunctional acid, 2-[10-(9,10-dihydro-9-oxa-10-phosphaphenantrene-10-oxide-10-yl)]-maleic acid (DOPO-MA) as monomer. Characterization of DOPO-MA and M-UPR was performed using element analysis, ¹H-NMR, or FT-IR. The curing of M-UPR was measured by differential scanning calorimetry, and the optimal cure temperature was calculated with DSC curves at different heating rates. The thermal stability was investigated with thermogravimetric analysis and comparative FT-IR analysis for char residue before and after heating. The flame-retardant property was determined by limiting oxygen index measurements and UL94 flammability meter. The viscoelastic property was measured with dynamic mechanical analysis. Owing to the incorporation of the rigid structure of pendant phosphorus groups, both thermal stability and flame retardancy of the resultant M-UPR have been improved.     

Interfacial microstructure and properties of carbon fiber-reinforced unsaturated polyester composites modified with carbon nanotubes

To improve the interfacial properties in carbon fiber (CF)-reinforced unsaturated polyester (UP) composites, we directly introduced functionalized carbon nanotubes dispersed in the fiber sizing onto the fiber surface. For comparing the influence of polymer type on sizing effect, two different polymers (UP MR13006 and water-soluble epoxy (EP)) were used to prepare sizing agent. Morphology and surface energy of CFs were examined by scanning electron microscopy and dynamic contact angle analysis test. Tensile strength was investigated in accordance with ASTM standards. Mechanical properties of the composites were investigated by interlaminar shear strength (ILSS) and impact toughness. Test results indicate that TS, ILSS, and impact toughness were enhanced simultaneously. For UP matrix, the sizing agent containing UP has better reinforcing and toughening effect than the sizing agent containing water-soluble EP.     

具有高伸长率的二异氰酸酯改性不饱和聚酯

介绍了1种新型二异氰酸酯改性不饱和聚酯,该树脂可以室温固化,固化后树脂的拉伸强度和断裂伸长率分别可达20 MPa和106%。该树脂可用于制作高柔韧性制品,亦可以加入到其他不饱和聚酯中,提高其冲击性能和断裂伸长率。     

Mechanical and thermal properties of modified kaolin clay/unsaturated polyester nanocomposites

The improvement in thermal and mechanical properties of Nanocomposites prepared with unsaturated polyester (UP) as polymer matrix and various loadings of amino‐modified nano kaolinite clay as filler has been studied. Mechanical stirring and ultrasonication resulted in better dispersion of the clay. For curing polyester resin, cobalt naphthenate was used as accelerator and MEKP as initiator. Dynamic Mechanical Analysis (DMA) was carried out to find storage and loss modulus. Thermal stability was found through thermogravimetric analysis and the evaluation of structure and morphology of the nanocomposites were done through XRD, SEM, and TEM. Nanocomposite with 3 phr of amino modified clay has shown higher storage modulus and an improved thermal stability of UP/clay nanocomposites has been established. Tensile strength and toughness of the composite have been found to achieve maximum values at 1 phr of clay and the storage modulus has had an improvement of 38% compared to neat UPR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43245.     

Curing reaction of saturated aliphatic polyester modified unsaturated polyester resins

Two series of unsaturated polyesters (UPE from isophthalic acid, fumaric acid, and propylene glycol) were prepared. In series-A resins, UPEs wee thickened with isocyanate-terminated saturated aliphatic polyestes, i.e., an isocyanate-terminated polycaprolactone diol (PE-di-OL), through reaction of the isocyanate group with the hydroxyl group of the UPE. In series-B resins, the UPEs were mixed with saturated aliphatic polyesters i.e., PE-di-OL. The curing reaction of these two series of UPEs with styrene was studied by using differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). The DSC data show that for a fixed PE-di-OL molecular weight, the curing reaction rate of series-A UPE is faster than that of series-B UPE. The variation of microgel size during curing ws studied by GPC. These results revealed that microgel formation has a great effect on the kinetics of cure for the unsaturated polyester-styrene system. The curing of these two series of UPEs is found to strongly depend on the compatibility of the components in the curing system.     

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。     

MAP-POSS改性不饱和聚酯树脂的固化反应

为改进不饱和聚酯（UP）树脂的性能,用非等温差示扫描量热法（DSC）研究了甲基丙烯酰氧丙基笼形倍半硅氧烷（MAP-POSS）与通用UP树脂的共同化反应。UP、苯乙烯和MAP—POSS有较好的相容性,可共同固化,MAP-POSS可均匀分散在UP基体中形成原位纳米分子复合材料。测定了固化动力学参数,建立了固化反应动力学数学模型。     

Curing studies on modified epoxy and unsaturated polyester resins

Experimental studies were carried out on the curing behavior of unsaturated polyester and epoxy resins. The latter were modified with three different fillers (CaCO₃, CaSiO₃, and glass powder) and their curing behaviors studied. Polyesters exhibited faster cure rates than the epoxy resins. The gel time of the epoxy resins decreased with the addition of fillers. Data indicated that the peak exotherm of these thermosetting resins increased when filled with glass powder. The hardness of the curing mass increased with curing time. The use of gel-hardness number as a quality control parameter has been suggested.     

Monitoring epoxy and unsaturated polyester reactions under pressure—Reaction rates and mechanical properties

The effects of pressure on reaction rates and final mechanical properties were studied for an unsaturated polyester (UP) and epoxy resin. A pressure chamber where reactions can be monitored by use of Raman spectroscopy has been built for these purposes. The chamber allows for pressures up to 13.8 MPa at 200°C. An advanced temperature control system has been adapted to the vessel to precisely control and monitor sample temperature variations and overshoots. It is described how for an accelerated UP reaction increasing pressure will result in a competing effect on the reaction rate where the rate will initially lower, but with increased pressures it may accelerate due to acceleration of the reaction rate constants. The final mechanical properties exhibit a similar behavior slightly increasing with pressure but lowering as pressure is raised further. For epoxy, it was shown that the reaction kinetics were accelerated by pressure although no mechanical property differences could be noted for the pressure ranges tested. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers.     

Mechanical properties of woodflour unsaturated polyester composites

Agrowastes and woodflour are a potential and attractive alternative of cheap reinforcement for brittle polymeric materials because they can reduce costs and, at the same time, improve certain properties. On the other hand, their high moisture sorption and low microbial resistance are disadvantages that need to be considered and, as far as possible, corrected. Polyester resins are widely used throughout the world, and can be processed with reinforcing agents very easily. In this work, the effect of the addition of chemically modified woodflour on the final properties of unsaturated polyester composites was studied. The filler was treated with an alkaline solution to increase its interfacial area and then modified with maleic anhydride (MAN) under severe reaction conditions (140°C, 24 h). No improvement in the mechanical behavior of polyester–woodflour composites was found when particles were only alkali treated, while the composites prepared with MAN-treated woodflour offered better performance under compressive loads. Simple mechanical models used to fit the experimental flexural behavior indicated that a good compatibility between filler and matrix was obtained regardless of the kind (treated or untreated) of reinforcement used. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2121–2131, 1998     

松香改性对苯型不饱和聚酯树脂的合成及性能

合成了松香封端改性对苯型不饱和聚酯树脂,研究了不同催化剂对转化率的影响,确定了最佳催化剂组成及用量。对比了改性前后对苯型以及通用邻苯型不饱和聚酯浇注体的物理力学性能、热性能和耐腐蚀性。结果表明:单丁基氧化锡和辛酸亚锡按1∶1质量比复合,用量为对苯二甲酸质量的0.5%时催化效果最佳。松香改性对苯型不饱和聚酯树脂在力学性能、耐酸碱腐蚀和耐水性方面均优于邻苯型树脂,较未改性对苯型不饱和聚酯树脂耐水、耐碱能力增强,与苯乙烯的相容性提高。     

UV curing of composites based on modified unsaturated polyester

Synthesis and photocrosslinking of glass fiber-reinforced composites, based on epoxy acrylate-modified unsaturated polyester, have been investigated. The efficiency of the photocrosslinking process for glass fiber laminates of the polyesters that contain different comonomers has been evaluated by measuring mechanical properties. The data show (i) that 2 mm thick laminates, containing 30–40% glass fiber mats, are cured with UV irradiation for 15 sec at room temperature in air; (ii) that multifunctional acrylate or acrylether monomers added to the polyester resin improve the tensile and flexural properties of the photocured product to a greater extent than do added allylic monomers, due to the different photocrosslinking mechanisms; (iii) that the physical properties of the photocrosslinked laminates are well correlated with the molecular weight of the polyester, the amount of multifunctional monomer added, and the glass fiber content. © 1994 John Wiley & Sons, Inc.     

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.     

纳米SiO_2改性不饱和聚酯树脂的研究进展

综述了国内纳米SiO2改性不饱和聚酯树脂(UPR)研究的最新进展,重点介绍了纳米SiO2用量、粒子尺寸、表面改性处理等因素对纳米SiO2/UPR复合材料性能的影响及纳米粒子增韧增强的机理,指出了纳米SiO2改性UPR存在的问题和可能的发展方向。     

Cure behavior of unsaturated polyester/modified montmorillonite nanocomposites

Dynamic rheology, differential scanning calorimetry and in situ Fourier transform infrared spectroscopy were used to study the cure behavior of unsaturated polyester/modified montmorillonite nanocomposites. The results showed that their gel times increased markedly at the same cure temperature, and that the activation energy of the nanocomposites was higher than that of the pure unsaturated polyester. Their peak temperatures of enthalpy increased as well. The total exotherm of the cure reaction declined and the cure rate decreased. In the curing process of pure unsaturated polyesters, the conversion of styrene was higher than that of the double bonds on unsaturated polyester macromolecular chains. The cure mechanism of the unsaturated polyester/modified montmorillonite changed because of the presence of double bonds in the layers of modified montmorillonite. However, the conversion of styrene in the nanocomposites was lower than that of double bonds on unsaturated polyester chains during cure at room temperature, and the conversion of styrene was increased after post‐curing and was higher than that of the double bonds on unsaturated polyester chains at the end of the cure reaction. Moreover, the degree of reaction of double bonds on unsaturated polyester chains of the nanocomposites was higher than that of unsaturated polyesters. Copyright © 2006 Society of Chemical Industry     

苯乙烯对不饱和聚酯树脂性能的影响

本文主要探讨了不饱和聚酯中应用得最广泛的活性稀释剂——苯乙烯，对不饱和聚酯树脂机械性能、电性能、吸水性、耐化学性等的影响，从而为实际生产中采用最佳的苯乙烯含量提供参考。     

Synthesis and mechanical properties of unsaturated polyester based nanocomposites

Two classes of nanocomposites were synthesized using an unsaturated polyester resin as the matrix and sodium montmorillonite as well as an organically modified montmorillonite as the reinforcing agents. X‐ray diffraction pattern of the composites showed that the interlayer spacing of the modified montmorillonite expanded from 1.25 nm to 4.5 nm, indicating intercalation. Glass transition values of these composites increased from 72°C, in the unfilled unsaturated polyester, to 86°C in the composite with 10% organically modified montmorillonite. From Scanning Electron Microscopy, it is seen that the degree of intercalation/exfoliation of the modified montmorillonite is higher than in the unmodified one. The mechanical properties also supported these findings, since in general, the tensile modulus, tensile strength, flexural modulus, flexural strength and impact strength of the composites with modified montmorillonite were higher than the corresponding properties of the composites with unmodified montmorillonite. The tensile modulus, tensile strength, flexural modulus and flexural strength values showed a maximum, whereas the impact strength exhibited a minimum at approximately 3–5 wt% modified montmorillonite content. These results imply that the level of exfoliation may also exhibit a maximum with respect to the modified montmorillonite content. The level of improvement in the mechanical properties was substantial. Adding only 3 wt% organically modified clay improved the flexural modulus of unsaturated polyester by 35%. The tensile modulus of unsaturated polyester was also improved by 17% at 5 wt% of organically modified clay loading.     

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。