氯甲基笼型倍半硅氧烷改性双酚A环氧树脂性能

引言双酚A环氧树脂是目前应用最广、用量最大的环氧树脂,具有良好的化学稳定性、电气绝缘性被广泛应用于涂料和电子电器等领域;然而,双酚A环氧树脂存在耐热性较差和固化后脆性大等缺点,因此如何提高环氧树脂的耐热性及力学性能等是目前改性研究的热点之一[1-5]。而笼型多面体倍半硅氧烷(POSS)是一类具有(RSiO1.5)n通式的纳米材料,因其特殊的分子组成结构使得POSS具     

环氧树脂/ABS复合材料的制备及性能表征

以环氧树脂为基体,苯乙烯-丙烯腈-丁二烯（ABS）树脂为增韧剂,制备了环氧树脂/ABS复合材料,讨论了增韧剂对复合材料的热性能和机械性能的影响。结果表明,ABS的添加可提高复合材料的断裂韧性。扫描电镜结果显示,基体的剪切屈服和橡胶颗粒的微孔洞是ABS增韧环氧树脂的主要增韧机理。     

新型潮湿表面用固化剂的合成

以间苯二甲胺(MXDA)和环氧氯丙烷(ECH)为原料,在物料物质的量比(MXDA/ECH)为2.1/1,反应温度为60℃,反应时间为2.5 h的工艺条件下合成环氧-胺加成物。然后与N,N-二甲基甲酰胺(DMF)反应,端胺基-多胺加成物与DMF的物质的量的比为1∶2.4,温度为110℃;最后用单环氧化合物封掉多余仲胺生成了一种新型可潮湿固化的固化剂(H-APMD)。对合成条件进行了优化。采用红外光谱法确定了分子结构。采用热重分析研究了涂膜的性能。结果表明,该固化剂是一种优良的潮湿固化固化剂。     

N-对羧苯基马来亚胺固化邻甲酚醛环氧树脂

合成了N-对羧基苯基马来酰亚胺,并将其用作邻甲酚醛环氧树脂的固化剂。对固化产物的热分析结果表明:N-对羧基苯基马来酰亚胺可明显提高邻甲酚醛环氧树脂的耐热性能,固化产物的起始热分解温度为278℃,分解10%时的温度为348℃,700℃时的残炭分数为45%。     

热引发前线聚合法固化脂环族环氧树脂

采用热引发前线聚合（TFP） 方法固化了脂环族环氧树脂（221树脂）,研究了固化剂用量、预热温度和反应器倾斜角度等因素对聚合前线的推动速率和前线温度的影响,并利用FTIR、DSC、TG等手段对固化物结构和热性能进行了表征。研究结果表明,固化剂用量越大或预热温度越高,引发前线聚合反应所需的时间越短,前线推动速率V_f 越快,前线最高温度T_max 越高,达到最高前线温度所需时间越短;试管倾斜一定角度后,下行前线方向发生偏离,V_f有所下降;FTIR测试结果表明,采用TFP法得到的环氧固化物与采用传统热固化工艺得到的固化物有相似的红外吸收,DSC和TG测试结果表明前线聚合产物具有更高的玻璃化温度和更好的热稳定性。     

Mechanical and thermal performances of epoxy resin/graphitic carbon nitride composites

In this paper, a series of graphitic carbon nitride (g-C₃N₄) was synthesized under different thermal oxidation etching temperatures and epoxy/g-C₃N₄ composites were prepared via solution blending. The morphology and structure of g-C₃N₄ were investigated by transmission electron microscope, X-ray diffraction (XRD), Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The tensile fracture morphology and structure of epoxy resin (EP) composites were demonstrated by scanning electron microscopy and XRD, respectively. Mechanical properties of EP composites were characterized by tensile testing, and the thermal performances were investigated by dynamic mechanical thermal analysis and thermal gravimetric analysis. The results revealed that the active groups on g-C₃N₄ sheets increased under thermal oxidation etching and the C to N ratio of g-C₃N₄ decreased from 0.94 to 0.76 with the increasing etching temperature. Noticeably, the tensile strength of EP composites was enhanced by 58% with the addition of C₃N₄-NS-500 and the thermal properties were also improved significantly, including T_0.5 (the decomposition temperature at the mass loss of 50%) increased by 21.5 °C and glass transition temperature improved by 8 °C. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48598.     

新型环氧树脂胶粘剂的固化动力学研究

在不同升温速率下采用非等温差示扫描量热（DSC）技术对一种新型改性环氧树脂胶粘剂的固化反应过程进行了跟踪,并利用Kissinger、crane方程以及Arrhenius方程对该固化反应进行了动力学分析。结果表明,该固化反应的活化能为59.18kJ／mol,反应级数为0．89;结合Dsc谱图确定其固化工艺为130℃／1h＋150℃／2h＋175℃／3h。     

Heavy crude oil asphaltenes as a nanofiller for epoxy resin

Asphaltenes are harmful components of heavy crude oils and require rational utilization after oil refining or deasphalting. Asphaltenes are macromolecules containing various functional groups that self-assemble to nanoscale aggregates and can be used as nanofillers for polymers. In this research, mixtures of asphaltenes with the diglycidyl ether of bisphenol A were considered. The solubility of asphaltenes in this epoxy resin, the rheological properties of the mixtures, and the effect of asphaltenes on the curing with 4,4′-diaminodiphenyl sulfone were studied. In addition, the glass transition temperature, strength, and adhesion characteristics of the asphaltene-filled cured composites were evaluated. The dual role of asphaltenes in polymer modification was demonstrated: the asphaltenes simultaneously plasticize and reinforce the polymer matrix, and the transition from predominant plasticization to strengthening occurs with an asphaltene content at 20 wt%. The dual reinforcement/plasticization effect occurs because epoxy composites contain both nanosized and microsized particles of asphaltenes due to the partial dissolution of asphaltenes in the epoxy resin and the decrease in their solubility during high-temperature curing.     

Modeling the evolution of the dynamic mechanical properties of a commercial epoxy during cure after gelation

The cure kinetics for a commercial epoxy have been established and the influence of the degree of cure on the glass transition determined. Time‐temperature and time‐conversion superposition principles have been built into a model that successfully predicts the development of the viscoelastic properties of the epoxy during isothermal cure from gelation to after vitrification. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 495–508, 2000     

新型液晶聚氨酯/环氧树脂复合材料的制备及性能

以联苯二酚,2,4-甲苯二异氰酸酯(2,4-TDI),乙二醇,N,N'-二(ω-羟乙基)均苯四甲酰二亚胺(BHDI)为单体,加成反应合成了1种同时含有联苯基和亚胺基的新型液晶聚氨酯(LCPBI),通过IR,DSC、偏光显微镜及X射线衍射仪对其结构和性能进行表征和分析。将该液晶聚氨酯与环氧树脂(E-51)共混制备了液晶聚氨酯/环氧树脂复合材料,通过力学性能测试,热重分析和电镜分析对其性能进行了研究并探讨了其增韧机理。结果表明,加入质量分数为3%的LCPBI,可使复合材料的冲击强度提高2.5倍,拉伸强度和弯曲强度也有不同程度的提高,热分解温度提高15～20℃。     

笼型倍半硅氧烷(POSS)/环氧杂化树脂体系固化反应动力学及性能研究

为了提高环氧树脂的耐热性,采用笼型倍半硅氧烷(POSS)改性双酚A型环氧树脂E51,得到有机无机杂化树脂。采用Ozawa和Kissinger两种方法研究了杂化树脂/4,4′-二氨基苯砜(DDS)体系的固化反应动力学。TGA分析表明,POSS的加入提高了E51/DDS固化树脂体系的热性能。     

The influence of cure conditions on the morphology and phase distribution in a rubber-modified epoxy resin using scanning electron microscopy and atomic force microscopy

In this paper, we consider the effect of cure conditions on the morphology and distribution of the rubber in a phase separated rubber-modified epoxy resin, which in effect is a two phase composite. Novel aspects of this study were measuring the elastic modulus of the dispersed rubber phase particles by atomic force microscopy (AFM) and verifying the presence of nano-dispersed rubber.The purpose of introducing dispersed rubber particles into the primary phase in these systems is to enhance their toughness. It is known that both the rubber particle size and volume fraction affect the degree to which the epoxy is toughened. It is not known, however, how the specific mechanical properties of the rubber phase itself affect the toughness.The objectives of this study were to: (1) use scanning electron microscopy (SEM) and atomic force microscopy (AFM) to determine the morphology and phase distribution of the rubber particles and (2) to measure the mechanical properties of the rubber particles using AFM. Ultimately, we would like to develop a clear understanding of how the changes in morphology and mechanical properties measured at the micro and nano-scales affect both the elastic modulus and fracture toughness of rubber-modified epoxy polymers.The epoxy system consisted of a diglycidyl ether of bisphenol-A, Epon 828, cured with piperidine and incorporating a liquid carboxyl-terminated acrlonitrile-butadiene rubber (CTBN). The carboxyl groups of the rubber are capable of reacting with the epoxy. The cure conditions considered were based on a statistically designed full factorial curing matrix, with the variables selected being cure temperature, initiator (piperidine) concentration, and rubber acrylonitrile concentration.Each of these primary variables was found to affect the phase distribution that resulted during cure. A statistical analysis of the effect of these variables on the phase morphology showed that the acrylonitrile content (%) of the rubber affected both the rubber particle size and volume fraction. The cure temperature strongly influenced the rubber particle volume fraction and modulus. Volume fractions of the rubber phase of up to 24% were obtained even though the amount of rubber added was only 12.5%. The rubber particle modulus varied from 6.20 to 7.16 MPa. Both the volume fraction and modulus of the rubber particles were found to influence the macroscopic mechanical properties of the composite. While larger volume fractions favor improved toughness, we note that that the toughness is greatest when the particle modulus values do not exceed ∼6.2 MPa. Thus, increased volume fraction by itself may not always result in increased toughness. The particles also must be sufficiently ‘soft’ in order to improve toughness. In the system of interest here, the processing conditions are a key factor in achieving the most appropriate material properties. By inference, this is likely to be the case as well in other rubber-modified thermosets.     

Nonisothermal cure of bisphenol epoxy resin with a nonlinear aliphatic polyamine hardener

The amino terminated polypropylenimine dendrimer (DAB‐dendri‐(NH₂)₄) was employed as a new nonlinear aliphatic curing agent for diglycidyl ether of bisphenol A (DGEBA). Nonisothermal curing reaction kinetics of DGEBA/DAB was investigated with a differential scanning calorimeter (DSC). The apparent reaction activation energy E_a is about 56.7 kJ/mol determined using the Kissinger equation, and a two‐parameter (m, n) autocatalytic model ([icirc]Sesták–Berggren equation) was confirmed to be able to well simulate the reaction kinetics in the light of the Málek method. In addition, the relation between reaction activation energy E_a and curing degree α was obtained by applying model‐free isoconversional analysis with the Kissinger‐Akahira‐Sunose (KAS) method. As α increases, E_a reduced quickly from >80 kJ/mol to ≈60 kJ/mol up to a ≈ 15%, then decreased slowly to 55 kJ/mol till a ～ 75%, and finally dropped to 44 kJ/mol at full conversion. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

GMA改性热固性环氧树脂颗粒的研究

采用化学接枝和辐射接枝两种方法,在热固性环氧树脂颗粒上接枝甲基丙烯酸缩水甘油酯(GMA)单体。通过红外光谱和计算接枝率的方法研究了反应条件对此接枝反应的影响,探讨了这两种接枝方法的最佳反应条件。     

Cure kinetics and thermal properties of tetramethylbiphenyl epoxy resin/phthalazinone‐containing diamine/hexa(phenoxy)cyclotriphophazene system

Inherently flame retardant epoxy resin is a kind of halogen‐free material for making high‐performance electronic materials. This work describes an inherently flame retardant epoxy system composed of 4,4′‐diglycidyl (3,3′,5,5′‐tetramethylbiphenyl) epoxy resin (TMBP), 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐(4‐(4‐aminophenoxy) phenyl) (2H) phthalazin‐1‐one (DAP), and hexa(phenoxy) cyclotriphophazene (HPCTP). The cure kinetics of TMBP/DAP in the presence or absence of HPCTP were investigated using isoconversional method by means of nonisothermal differential scanning calorimeter (DSC). Kinetic analysis results indicated that the effective activation energy (E_α) decreased with increasing the extent of conversion (α) for TMBP/DAP system because diffusion‐controlled reaction dominated the curing reaction gradually in the later cure stage. TMBP/DAP/HPCTP(10 wt %) system had higher E_α values than those of TMBP/DAP system in the early cure stage (α < 0.35), and an increase phenomenon of E_α ～ α dependence in the later cure stage (α ≥ 0.60) due to kinetic‐controlled reaction in the later cure stage. Such complex E_α ～ α dependence of TMBP/DAP/HPCTP(10 wt %) system might be associated with the change of the physical state (mainly viscosity) of the curing system due to the introduction of HPCTP. These cured epoxy resins had very high glass transition temperatures (202–235°C), excellent thermal stability with high 5 wt % decomposition temperatures (>340°C) and high char yields (>25.6 wt %). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

风电叶片用环氧树脂固化体系的研究

分别以BH-1、2,4,6-三(二甲氨基甲基)苯酚(DMP-30)和2-乙基-4-甲基咪唑(2,4-EMI)作为促进剂,研究了三种不同促进剂对环氧树脂(EP)/酸酐固化体系力学性能和耐热性能的影响;并以此作为复合材料的基体树脂,以玻璃纤维作为增强材料,制备风电叶片用EP基玻璃纤维增强复合材料。结果表明:三种基体树脂及其玻璃纤维增强复合材料均具有优异的力学性能,能够用于风电叶片的制备;其中以BH-1为促进剂的EP/酸酐体系具有最好的韧性和综合力学性能,其最大拉伸强度超过80MPa,断裂伸长率为3.80%。     

新型环氧树脂固化剂的合成及其环氧胶粘剂

以4,4’-二氨基二苯甲烷为原料,经乙酰化、硝化、酸解、还原、中和5步反应合成得到了一种新型环氧树脂固化剂,即3,3’,4,4’-四氨基二苯甲烷,并通过FT—IR分析及熔点测定对其进行了表征。此外,对改性环氧树脂／3,3’,4,4’-四氨基二苯甲烷体系也作了性能研究。     

Preparation,characterization, and polymerization of novel maleimidobenzoxazine containing carboxylic moiety and its cocuring behaviors with epoxy resin

A novel benzoxazine containing maleimide and carboxylic moieties, 1‐[3‐(4‐carboxylphenyl)‐3,4‐dihydro‐2H‐benzo[e][1,3]‐oxazin‐6‐yl]maleimide (Mal‐Bz‐Co), was synthesized and the structure was identified by ¹H‐NMR and FTIR. Mal‐Bz‐Co exhibited good solubility in common organic solvents. The cure behavior of Mal‐Bz‐Co and cocure behavior of Mal‐Bz‐Co with o‐cresol formaldehyde epoxy resin were investigated by differential scanning calorimetry. Results indicated that Mal‐Bz‐Co showed a single curing exothermic peak at about 238.3°C. However, the maximum curing temperature (T_p) decreased to 146.1°C when Mal‐Bz‐Co cocured with o‐cresol formaldehyde epoxy resin in the molar ratio of 1 : 1. The T_p was about 92°C lower than that of Mal‐Bz‐Co. Thermogravimetric analysis showed that high‐decomposition temperature and char yield were observed for the cured resins of Mal‐Bz‐Co and Mal‐Bz‐Co/o‐CFER. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

新型双马来酰亚胺改性环氧树脂体系性能研究

用含二氮杂萘联苯结构的双马来酰亚胺(DHPZ-BM I)与4,4'-二氨基二苯砜(DDS)为复合固化剂固化环氧树脂(E-51)。采用示差扫描量热仪(DSC)研究了该体系的固化反应动力学,求得固化反应表观活化能Ea=63.28 kJ/mol,碰撞因子A=1.55×106s-1,反应级数n=0.89,该体系与链延长型双马来酰亚胺PPEK-BM I(DP=15)/DDS/E-51体系的固化反应动力学数据几乎相同,证明二者的固化反应过程相同。采用热失重分析仪(TGA)分析研究了上述2种固化体系的热分解动力学,前者的热分解活化能达215.04 kJ/mol,为后者的1.5倍以上,说明DHPZ-BM I/DDS/E-51是1种热稳定性能良好的耐高温环氧树脂体系。     

环氧树脂固化促进剂的研究

以甲苯二异氰酸酯(TDI)和3-二甲氨基丙胺为单体、甲苯为溶剂,合成了环氧树脂(EP)的固化促进剂——甲苯-2,4-二(N,N′-二甲氨基丙脲)。为了验证自制促进剂的性能,以EP/双氰胺/促进剂为基体,并辅以填料、增韧剂、沉淀硫酸钡和流平剂等助剂,制备了粉末涂料。结果表明:制备促进剂的最佳工艺条件为n(TDI)∶n(3-二甲氨基丙胺)=1∶1.8、3-二甲氨基丙胺/甲苯溶液的滴加时间为1.5 h;当w(促进剂)=2.0%、固化温度为160℃时,粉末涂料的固化时间为6.5 min、胶化时间约100 s,并且其硬度、附着力和柔韧性俱佳,完全满足生产要求和使用要求。