Morphology,thermal and mechanical properties of epoxy adhesives containing well-dispersed graphene oxide

Graphene oxide (GO) is prepared and introduced into epoxy resins through a wet-transfer migration technique using a three-roll mill. The results of TEM, XRD and digital microscope observation show that good dispersion of GO is achieved without using any additives. The mechanical and thermal properties of GO/epoxy (GO/EP) adhesives are enhanced with GO incorporated. A 10.2% increase in Young's modulus and a 56.3% increase in elevated-temperature (120 °C) lap shear strength (LSS) was observed on addition of 1.0 wt% GO, compared to the neat epoxy adhesive. Increased glass transition temperature and improved thermal stability of the GO/EP adhesives are also observed in the DMA and TG analysis. Moreover, the toughness of the GO/EP adhesives is improved and much rougher fracture surface can be observed compared with the neat epoxy adhesive. No GO agglomeration can be observed in the SEM images of GO/EP adhesive with 1.0 wt% loading.     

风电叶片用EP胶粘剂的研究

以不同增韧剂改性EP(环氧树脂)为基体树脂,采用曼尼希改性胺为固化剂制备了不同改性EP胶粘剂。研究结果表明:当增韧剂为聚氨酯(PU)预聚体时,相应的改性EP胶粘剂的粘接性能优异;在上述体系中加入玻璃纤维增强填料后,相应的改性EP胶粘剂的综合力学性能和粘接性能俱佳,其拉伸强度超过75.00 MPa、拉伸模量超过4.00 GPa、断裂伸长率超过4.00%且90°剥离强度超过10.00 kN/m,属于高韧性EP胶粘剂,并且完全满足风电叶片的使用要求。     

聚氨酯改性环氧树脂的制备及其粘接性能

制备了聚氨酯(PU)改性环氧树脂(EP),使用红外光谱(FT-IR)和扫描电子显微镜(SEM)对其结构进行了表征,并对其固化物的热性能和动态热机械性能进行了研究;以PU改性EP为基体树脂制备胶粘剂,并对该胶粘剂的性能进行了测定。实验结果表明,由于PU链段可以改善EP的韧性,并且两者相容性较好,故由此制取的胶粘剂综合性能良好,其拉伸剪切强度为16MPa、粘接拉伸强度为35MPa且断裂伸长率为1.8%。     

低温抗结晶型粘钢胶的性能研究

以含环氧基酚基树脂(X)作为通用EP(环氧树脂)胶粘剂的改性剂,制备了低温抗结晶型EP粘钢胶,并着重探讨了X对粘钢胶的基本力学性能、耐温变性能、抗结晶性能和综合性能等影响。结果表明:X改性粘钢胶的基本力学性能随温度或龄期的增加而不断增大;当w(X)=20%或30%时,X改性粘钢胶具有良好的抗结晶性能和力学性能;通过调整配方,可配制出满足GB50367—2006标准(A级)的抗低温结晶型粘钢胶。     

Synthesis,characterization and properties of organoclay‐modified polyurethane/epoxy interpenetrating polymer network nanocomposites

organoclay‐modified polyurethane/epoxy interpenetrating network nanocomposites (oM‐PU/EP nanocomposites) were prepared by adding organophilic montmorillonite (oMMT) to interpenetrating polymer networks (IPNs) of polyurethane and epoxy resin (PU/EP) which had been prepared by a sequential polymerization technique. Wide‐angle X‐ray diffraction (WAXD) and transmission electronic microscopy (TEM) analysis showed that the interpenetrating process of PU and EP improved the exfoliation and dispersion degree of oMMT. The effects of the NCO/OH ratio (isocyanate index), the weight ratio of PU/EP and oMMT content on the phase structure and the mechanical properties of the oM‐PU/EP nanocomposites were studied by tensile testing and scanning electronic microscopy (SEM). Water absorption tests showed that the PU/EP interpenetrating networks and oMMT had synergistic effects on improvement in the water resistance of the oM‐PU/EP nanocomposites. Differential scanning calorimetry (DSC) analysis showed that PU was compatible with EP and that the glass transition temperature (T_g) of the oM‐PU/EP nanocomposites increased with the oMMT content up to 3 wt%, and then decreased with further increasing oMMT content. The thermal stability of these nanocomposites with various oMMT contents was studied by thermogravimetric analysis (TGA), and the mechanism of thermal stability improvement was discussed according to the experimental results. Copyright © 2005 Society of Chemical Industry     

High performance epoxy resin nanocomposites containing both organic montmorillonite and castor oil-polyurethane

Summary Epoxy resin/polyurethane interpenetrating polymer network nanocomposites with various contents of organophilic montmorillonite (oM-EP/PU nanocomposites) were prepared by a sequential polymeric technique and an in situ intercalation method. X-ray diffraction(XRD), and transmission electronic microscopy(TEM) analysis showed that organophilic montmorillonite (oMMT) disperses uniformly in epoxy resin/polyurethane interpenetrating networks(IPNs), and the intercalated or exfoliated microstructures of oMMT are formed. Differential scanning calorimetry(DSC) test proved that oMMT promotes the compatibility of EP phase and PU phase, and glass transition temperature(T_g) of oM-EP/PU nanocomposites improves with increasing oMMT content. Mechanical properties tests and thermal gravity analysis (TGA) indicated that oMMT and the IPNs of EP and PU exhibit synergistic effect on improving mechanical and thermal properties of pure EP. The mechanism of toughing and reinforcing of oM-EP/PU nanocomposites was further discussed by scanning electronic microscope(SEM).     

环氧大豆油改性透明环氧树脂胶粘剂的研究

以环氧大豆油(ESO)为环氧树脂(EP)的增塑剂、环氧氯丙烷(ECH)和丙烯腈(AN)改性己二胺为固化剂,制得ESO改性EP胶粘剂。探讨了增塑剂种类和含量对EP胶粘剂性能的影响。结果表明:当n(己二胺):n(ECH):n(AN)=1:0.3:1.5、w(ESO)=20%时,相应EP胶粘剂的剪切强度、断裂伸长率和外推起始温度分别比纯EP体系增加了10%、400%和20%;ESO是一种高增韧性、高耐热性的环保型增塑剂,相应EP胶粘剂的透明性、柔韧性和耐高(低)温性俱佳。     

水性环氧树脂包覆有机蒙脱土制备木材胶粘剂

摘要：水性环氧树脂通常含有水溶性分子或分子链，导致在高温和潮湿条件下作为木材胶粘剂时耐水性及力学性能较差。采用有机改性的纳米蒙脱土改性水性环氧树脂增强水性环氧树脂胶粘剂的耐水性及力学性能。并通过乳液包覆蒙脱土的方法与直接共混的方法对比，研究了不同添加量有机蒙脱土（0%，3%，6%，9%）对胶粘剂性能的影响。胶粘剂的耐水性及力学性能通过测量胶粘剂在干燥及潮湿条件下的剪切强度来表示。通过TGA、SEM、TEM、DSC研究了复合胶粘剂的热稳定性和结构。结果表明，在水性环氧树脂中添加有机改性的纳米蒙脱土，可以有效地提高胶粘剂的粘结强度，此外，采用乳液包有机覆蒙脱土的方法比直接共混的方法制备得到胶粘剂，有机蒙脱土在胶粘剂中分布更均匀，具有更优异的力学性能，说明有机蒙脱土在复合材料中的分散质量是影响复合胶粘剂性能的主要原因。     

Study on epoxy resins modified by polycarbonate polyurethanes

In this article, the structure and properties of the epoxy resin (EP) modified by polyurethane (PU) prepolymers were studied. The three types of polyurethane prepolymers, namely, polycarbonate-type PU (TPC), polyether-type PU, and polycarbonate–polyether-type PU were employed. The samples were analyzed by means of an infrared spectrometer, a differential scanning calorimeter, a scanning electron microscope, a transmission electron microscope, a scanning tunnel microscope, and a thermal gravimeter. The results show that the EP modified by TPC is of excellent thermal resistance and mechanical properties. Specifically, when the ratio of PU to EP is 10/100 (wt/wt), optimal properties are achieved. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 887–893, 1998     

无溶剂建筑结构胶的制备与性能

以活性增韧剂CYH-277对环氧树脂进行稀释、增韧,制备了无溶剂建筑结构胶粘剂。对活性增韧剂的结构进行了表征,考查了CYH-277对环氧树脂黏度的影响,研究了固化物的热性能,并用扫描电子显微镜(SEM)表征其形态结构,测试了制备的无溶剂建筑结构胶粘剂的力学性能。结果表明,CYH-277能够有效降低环氧树脂的黏度,调整施工性能,改善环氧树脂胶粘剂的综合性能。     

二缩水甘油二甘醇胺封端聚氨酯/环氧树脂复合体系的热力学性能研究

以二缩水甘油二甘醇胺(DGDGA)作为端-NCO型聚氨酯(PU)预聚体的封端剂,合成出了具有高反应活性的二缩水甘油二甘醇胺封端的聚氨酯(DGDGAPU)。并用其改性环氧树脂,得到了固化速度匹配、相容性好的聚氨酯/环氧树脂复合体系。采用红外光谱(FT-IR)法对其结构进行表征,采用TG研究其热性能,通过冲击、压缩等方法研究其力学性能,并用SEM分析发现其形成了交联紧密的DGDGAPU/EP网络。结果表明,在加入50%环氧树脂时体系力学性能最佳。     

Nanotailoring of polyurethane adhesive by polyhedral oligomeric silsesquioxane (POSS)

The development and commercialization of nanoparticles such as nanoclays (NCs), carbon nanotubes (CNTs) and polyhedral oligomeric silsesquioxanes (POSS) offers new possibilities to tailor adhesives at the nanoscale. Four types of POSS, with reactive mono-functional groups of isocyanatopropyl, glycidoxypropyl, aminoethyl and non-reactive octaphenyl, were incorporated in concentrations of 1, 3 and 5 wt% into a polyurethane (PU)-based adhesive. Thermo-mechanical bulk properties were studied using dynamic mechanical analysis (DMA). Adhesive properties were characterized in shear and peel modes. Atomic force microscopy (AFM) was used to study the nanoscale morphology. DMA measurements indicated that the neat PU possessed a glass transition temperature (T _g) of ≈ 30°C. The T _g of PU/POSS-glycidoxypropyl nanocomposite adhesive increased gradually with POSS concentration to 50°C for 5 wt%. PU/POSS-octaphenyl nanocomposite adhesive exhibited an increased T _g by 10°C for 5 wt%. The incorporation of POSS-isocyanatopropyl in the PU had no effect on the T _g. With respect to shear properties of POSS-octaphenyl-, POSS-isocyanatopropyl- and POSS-glycidoxypropyl-based PU nanocomposite adhesives, shear strength improved by 230, 178 and 137%, respectively, compared to neat PU. POSS-aminoethyl exhibited lower shear and peel strengths, while POSS-isocyanatopropyl provided the best balance of both higher shear and peel strengths compared to neat PU. It was concluded that the grafted functional group on the POSS and its reactivity with the PU network components were the decisive factors with respect to the thermo-mechanical, morphological and adhesive properties of the resulting nanocomposite adhesives. Consequently, the POSS/polyurethane based nanocomposite adhesives could be tailored for a large range of applications.     

聚氨酯改性环氧树脂的合成及性能研究

以聚氨酯(PU)作为环氧树脂(EP)的增韧改性剂,考察了m(EP):m(PU)比例、活性稀释剂等对PU改性EP性能的影响.结果表明:当m(EP):m(PU)=80:20时,改性EP的韧性和强度同时提高,并且其耐热性最佳;活性稀释剂的加入能在一定程度上增韧、增强纯EP及改性EP,但两者的耐热性有所降低.     

新型快速固化环氧树脂胶粘剂的制备及性能

以己二酸、多胺(如二乙烯三胺、三乙烯四胺或多乙烯多胺等)为原料,采用熔融缩聚法合成了3种低黏度、低毒性且可室温固化的环氧树脂(EP)胶粘剂用聚酰胺固化剂(PA1、PA2或PA3)。探讨了固化剂含量对EP胶粘剂的固化速率和粘接性能等影响,并采用单因素试验法优选出EP/固化剂的最佳配比。结果表明:EP胶粘剂的固化速率和剥离强度依次为EP/PA1胶粘剂>EP/PA2胶粘剂>EP/PA3胶粘剂;当m(PA1):m(EP)=0.6:1.0、w(促进剂)=1.0%(相对于EP质量而言)、固化温度为80℃和固化时间为60min时,相应胶粘剂的适用期较长,并且加热后能快速固化,而且用该胶粘剂制备的包封膜经处理后,其综合性能良好,可满足柔性印刷电路板(FPC)的生产要求。     

Tribological mechanism improving the wear resistance of polyurethane/epoxy interpenetrating polymer network via nanodiamond hybridization

The excellent synergistic effect of physical/mechanical properties of polyurethane/epoxy (PU/EP) interpenetrating polymer network (IPN) and the validity of nanofilling have one potential to improve the wear resistance of polymeric materials. With the aim of practical application, PU/EP IPN nanocomposites are prepared with nanodiamond (ND) as a reinforcing additive. Results showed the uniform thermal stability and the excellent compatibility between PU and EP in ND‐hybridized PU/EP IPN. Simultaneously, ND particles work as crosslinked points improving the physical/mechanical properties of ND‐hybridized PU/EP IPN, especially the wear resistance. The measurement of tribological property and the scanning electron microscope indicated that the wear resistance is able to be improved a lot by the formation of IPN and by the addition of ND. Consequently, the tribological mechanism of PU/EP IPN nanocomposites comes into being. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40244.     

碳酸钙晶须改性环氧树脂胶粘剂的研究

以碳酸钙(CaCO3)晶须为EP(环氧树脂)胶粘剂的增强填料,研究了填料种类、含量及表面处理方法等对EP胶粘剂性能的影响。结果表明:在其他条件保持不变的前提下,未改性CaCO3晶须可使EP胶粘剂的拉伸剪切强度提高10%~80%,耐热性略有提高,其外推起始热分解温度为370℃;对CaCO3晶须用质量分数为1%的硅烷偶联剂进行表面处理后,其可使EP胶粘剂的拉伸剪切强度提高30%~110%;CaCO3晶须是一种应用前景良好的胶粘剂用增强填料。     

Synthesis and properties of polyurethane wood adhesives derived from crude glycerol-based polyols

Crude glycerol, a waste stream of the biodiesel production process, is low-cost renewable feedstock for the production of chemicals and polymers. In this study, polyurethane (PU) adhesives were synthesized from crude glycerol-based polyols (CG-based polyols) for wood bonding applications. Effects of different variables, including hydroxyl values of CG-based polyols, chain extenders, and the molar ratio of NCO/OH on the properties of PU adhesives were investigated. The chemical structures of PU adhesives were characterized, and their thermal, mechanical, and chemical resistance properties were evaluated. The experimental results indicated that an increase of the NCO/OH molar ratio (1.3) substantially improved bonding strength by up to 38 MPa. Higher thermal stability and stronger chemical resistance to hot and cold water and to alkali and acid solutions were observed comparing to vegetable oil-based adhesives. However, the effect of the hydroxyl value of polyols on bonding strength was not significant. Additionally, bond strength of crude glycerol-based PU adhesives was comparable to that of some commercial PU wood adhesives. All these properties demonstrated the potential of CG for PU wood adhesive applications, particularly for fast-curing uses.     

Preparation and properties of waterborne polyurethane adhesives modified by polystyrene

Waterborne polyurethane (WPU) adhesives modified by polystyrene (PS) were prepared through a prepolymer mixing process from diisocyanates, an anionic polyester, internal emulsifiers, a neutralizer, a chain extender, and PS dispersions. The latter was preformed via the in situ polymerization of styrene in poly(1,4‐butanediol adipate) diol. Transmission electron microscopy, Fourier transform infrared spectroscopy, and ¹H‐NMR techniques were used to characterize the PS dispersions and polyurethane (PU)–PS prepolymer. Experimental results with respect to the performance of the PU–PS adhesives indicate that suitable PS/polyester diol weight ratios improved the mechanical properties, thermal stability, water resistance, and initial adhesive strength of the pristine WPU adhesives. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Interpenetrating polymer networks of bismaleimide and polyether polyurethane–crosslinked epoxy

In this work, we prepared the interpenetrating polymer networks of bismaleimide and polyether-type polyurethane(polyoxypropylene)–crosslinked epoxy (BMI/PU(PPG)–EP IPNs) by employing the simultaneous bulk polymerization technique. The polyurethane (PU)–crosslinked epoxy was identified via infrared (IR) spectra analysis. Also investigated herein were the mechanical properties, including tensile strength, Izod impact strength, and fracture energy (G_IC) of the IPNs with various BMI contents in PU–crosslinked epoxy matrix. In addition, differential scanning calorimetry (DSC) analysis and the thermogravimetric analysis (TGA) were performed to examine the thermal properties of the BMI/PU(PPG)–EP IPNs. In addition, morphology and dynamic mechanical analysis (DMA) of the BMI/PU(PPG)–EP IPNs were also studied. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2635–2645, 1998     

示温粘接涂层用胶粘剂的研究进展

胶粘剂在示温粘接涂层的成膜性、变色性等方面起着重要作用。在简要介绍胶粘剂对示温粘接涂层作用的基础上,重点介绍了近年来国内外各类胶粘剂[包括环氧树脂(EP)、酚醛树脂(PF)、有机硅树脂、醇酸树脂(AK)、氟碳树脂和丙烯酸酯类胶粘剂等]在示温粘接涂层中的研究现状,并对其发展趋势作了展望。