Evaluation of modification effect of epoxy resin based on performance of asphalt mixtures

Based on the analysis of the main failures discovered in pavement on steel deck plate and the demanding service condition of the pavement on steel deck, high-temperature rutting test, low-temperature bending test and controlled stress flexural fatigue test are used to study the performance of asphalt mixtures modified by epoxy resin including high-temperature stability, low-temperature cracking-resistance, and fatigue cracking-resistance, which are served to evaluate the modification effect of epoxy resin of different contents. With the addition of epoxy resin, all the three performances are improved greatly. However, when the amount of epoxy resin added is over a certain value, the modification effect will be stable with no extra benefit detected. Finally, in terms of the properties of the three respects, 20%, 30%, 30% are given separately as the proposal adding contents.

Improvements of heat resistance and adhesive property of condensed poly-nuclear aromatic resin via epoxy resin modification

A bisphenol epoxy resin was used as modifier to increase the heat resistance of condensed poly-nuclear aromatic （COPNA） resin. The basic properties of COPNA resin and modified resin were characterized by Fourier transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance spectroscopy （1H-NMR）, vapor pressure osmometry （VPO） and elemental analysis （EA）. Average structural parameters of resins were calculated by the improved Brown-Ladner method, and heat resistance of resins was tested by thermogravimetric analysis （TGA）. The chemical structure, mechanical properties and heat resistivity of the resin/graphite composites prepared with different resins were compared. The results show that the adhesive property and heat resistance of COPNA resin can be remarkably improved by addition of 5 wt.% epoxy resin. The reason is that the reactions between epoxy groups of epoxy resin and hydroxyl groups of COPNA resin improve the heat resistance and adhesive property of COPNA resin. Electric motor brushes with good mechanical properties and low electrical resistivity were successfully prepared by using the modified resin as binder.

Two-Stage Hydrogenation Modification of C_9 Petroleum Resin over NiWS/γ-Al_2O_3 and PdRu/γ-Al_2O_3 Catalysts in Series

Hydrogenation modification is one of the most important ways to produce high-quality petroleum resin. The col- orless C9 petroleum resin （CgPR） was obtained by two-stage catalytic hydrogenation over NiWS/？-A1203 catalyst and PdRu/ y-A1203 catalyst connected in series. Via the hydrogenation reaction, aromatic rings in C9PR were converted to alicyclic rings, and its color was reduced from Gardner color grade No. 11 to Gardner color grade No. 0. The optimum Ni/W atomic ratio was found to be close to 0.23, while the optimum Pd/Ru atomic ratio was close to 3.80. The TEM results showed that the morphology and size of sulfide or metal particles of the two kinds of catalysts remained almost unchanged after the reac- tion was carried our for 1 204 hours, attesting to their good catalytic stability.

Effect of Hyperbranched Polyester on Modification of Epoxy Resins Cured with Anhydride

The synthesis and characterization of hyperbranched polyester （HBP） with different molecular weight are studied. The effect of HBP on the modification of epoxy resins cured with anhydride is mainly discussed. The characteristics of HBP and the morphologies of cured system are determined by nuclear magnetic resonance spectroscopy （NMR）, gel permeation chromatography （GPC） and scanning electron microscope （SEM）. The impact strength of cured system is detected and Fourier transform infrared （FTIR） measurements were used to pursue the curing process. The investigation shows that HBP can improve the toughness by forming copolymer networks between epoxy resins, HBP and anhydride. Moreover, when the molecular weight of HBP is 1342g/mol the toughening effect is the best, and the changes of toughness are small with the increase of molecular weight of HBP to 3500 g/mol.

Effect of plasma step gradient modification on surface electrical properties of epoxy resin

In this paper,plasma fluorination is combined with plasma silicon deposition to achieve step gradient modification on an epoxy resin surface.The physicochemical characteristics of samples are investigated and the electrical performances measured.The obtained results show that compared with untreated and single treated samples,the samples treated by step gradient modification significantly improve the flashover performance.According to experiment and simulation,the mechanism explanations are summarized as follows.First,it is found that the step gradient conductivity can effectively optimize the electric field distribution of a needle-needle electrode.Then,step gradient modification suppresses the accumulation of surface charge at the triple junction and makes the charge distribution more uniform.Furthermore,it can accelerate the surface dissipation on a high electrical field region and control the dissipation rate on a low electrical field region.All these results can restrain surface discharge and increase the flashover voltage.The step gradient modification method proposed in this paper provides a new idea for improving the surface insulation performance.

MODIFICATION OF X-5 RESIN AND ADSORPTION PROPERTY OF THE MODIFIED RESINS

Three polymeric adsorbents with hydrogen bonding acceptors, methylamine, N-methyl-acetamide and aminotri(hydroxymethyl)methane modified resins are synthesized from chloromethylated X-5 resin. Adsorption isotherms of phenol and theophylline onto the three modified resins and the original X-5 resin from aqueous solution are measured. The results show that adsorption of compounds with hydrogen bonding donor onto methylamine and N-methylacetamide modified resins is enhanced as compared with that onto X-5 resin, and adsorption mechanism between the adsorbents and the adsorbates is mainly based on hydrogen bonding and hydrophobic interaction. While adsorption of compounds with hydrogen bonding donor onto aminotri(hydroxymethyl)methane modified resin is lowered as compared with that onto X-5 resin, and adsorption mechanism between the adsorbent and the adsorbates is mainly based on hydrophobic interaction.

ADSORPTION OF 2,4-DICHLOROPHENOL IN AQUEOUS SOLUTION ONTO ADSORPTION RESIN MODIFIED BY N-ACETYLANILINE

A hypercrosslinked adsorption resin （ZH-05） modified by N-acetylaniline in the post crosslinking process was prepared. The adsorption properties of ZH-05 toward 2,4-dichlorophenol in comparison with granular activated carbon （GAC） and Amberlite XAD-4 were observed. The present study mainly focuses on the static equilibrium adsorption behaviors, desorption profiles and the proof of chemisorption. The results show that the Langmuir equation can give a perfect fitting to experimental data, and high temperature was favorable for adsorption of 2,4-dichlorophenol on ZH-05. A related equation was used to correlate the amount of chemisorption and the suppositionai chemisorption equilibrium concentration of adsorbate in aqueous solution. The adsorption capacities from different ranges of temperature and the static desorption experiment both reveal the same conclusion, i.e., the adsorption of 2,4-dichlorophenol from water on ZH-05 is a coexistent process of physical adsorption and chemical transition as on GAC.

Synthesis and Properties of Perfluorinated Alkyl Silicone Oil Modified Epoxy Resin

Perfluorinated alkyl silicone oil （PFASO） was successfully synthesized from N-ethyl-N- hydroxylethyl perfluorinated octane sulfonamide, succinie anhydride and amino silicone oil by esterification and amide reaction at moderate temperature in the presence of different catalysts. The chemical structure of the synthesized samples was characterized by Fourier transform infrared spectroscopy （FT-IR）, the relative molecular mass（MM） and molecular mass distribution（MMD） of PFASO were tested by gel filtration chromatography（GFC）. A commercial epoxy resin （DGEBA） was modified with PFASO, with the content of PFASO 1-5 phr. Thermo-gravimetric analysis （TGA）, impact tests, scanning electron microscope （SEM） and water contact angle test were applied to provide accurate results on the thermal stability, toughness and hydrophobicity of PFASO/epoxy complex. The experimental results reveal that epoxy resins can be successfully modified by adding a small amount of as-synthesized modifiers via simple direct mixing, and verify that the as-synthesized modifier can improve the toughness and hydrophobicity of epoxy resin without sacrificing its thermal properties.

Effects of filler loading and surface modification on electrical and thermal properties of epoxy/montmorillonite composite

Epoxy-based composites containing montmorillonite(MMT)modified by silylation reaction withγ-aminopropyltriethoxysilane(γ-APTES)and 3-(glycidyloxypropyl)trimethoxysilane(GPTMS)are successfully prepared.The effects of filler loading and surface modification on the electrical and thermal properties of the epoxy/MMT composites are investigated.Compared with the pure epoxy resin,the epoxy/MMT composite,whether MMT is surface-treated or not,shows low dielectric permittivity,low dielectric loss,and enhanced dielectric strength.The MMT in the epoxy/MMT composite also influences the thermal properties of the composite by improving the thermal conductivity and stability.Surface functionalization of MMT not only conduces to the better dispersion of the nanoparticles,but also significantly affects the electric and thermal properties of the hybrid by influencing the interfaces between MMT and epoxy resin.Improved interfaces are good for enhancing the electric and thermal properties of nanocomposites.What is more,the MMT modified with GPTMS rather thanγ-APTES is found to have greater influence on improving the interface between the MMT filler and polymer matrices,thus resulting in lower dielectric loss,lower electric conductivity,higher breakdown strength,lower thermal conductivity,and higher thermal stability.

Curing mechanism of TDE-85/MeTHPA epoxy resin modified by polyurethane

Diglycidyl 4,5-epoxy tetrahydro phthalate/methyl tetrahydrophthalic anhydride （TDE-85/MeTHPA） epoxy resin modified by polyurethane （PU） was prepared with 1,4-butanediol （1,4-BDO）, trimethylol propane （TMP） and polyurethane prepolymer synthesized by polypropylene glycol and toluene diisocynate. Chemical reaction and curing mechanism of this system were discussed by incorporating the results of infra spectrum analysis. The results indicate that the epoxy polymeric network I is obtained by the curing reaction between TDE-85 and MeTHPA, while the PU polymeric network II is obtained by the chain-extended and crosslinking reaction between 1,4-BDO, TMP and polyurethane prepolymer（PUP）. The graft chemical bonds are formed between polymer networks I and II that therefore increase the degree of blend and compatibility between epoxy polymer and PU.

Ion Exchange Equilibrium between DOWEX 1X8 Resin Modified by Polyethyleneimine and Electrolyte Solutions

In order to improve the selectivity of anion exchange resin, the surface of gel type anion exchange resin was modified with polyethyleneimine (PEI). In the proposed work an attempt to the utilization of commercial anion exchange resin modified by adsorption of polyethyleneimine was investigated. Many conditions of modification of anion exchange resin surface were studied. The influent parameters on the DOWEX 1X8 resin modification were determined using a factorial experimental design. The ion exchange reactions were studied for modified and unmodified resin and electrolyte solutions containing Cl-,NO3-,SO42-. All experiments were performed at constant ionic strength I = 0.3 mol·L-1 and constant temperature T = 298 K. Ionic exchange isotherms were established for the binary systems:Cl-/NO3-,Cl-/SO42- and NO3-/SO42-. The obtained results show that nitrate ion was more sorbed than chloride and sulfate. The order of preference for the anions studied in this investigation is:NO3->Cl->SO42-. All the results given by this resin were compared with those obtained with the AMX anion exchange membrane. Selectivity coefficients and thermodynamic constants for the three binary systems and for the two resins were determined. The modified resin became more selective towards monovalent anions.

Curing mechanism of furan resin modified with different agents and their thermal strength

The curing mechanism of furfuryl alcohol and urea-formaldehyde furan resins was investigated using infrared spectroscopy(IR) technique.The curing productions of urea-formaldehyde furan resins modified with different agents(i.e.sorbitol,polyester polyol,phenol and acetone) and the productions of incomplete curing were characterized by differential thermal analysis(DTA) and thermal gravity analysis(TG).The results indicate that except for polyester polyol,the other modifiers have little effect on the thermal strength of urea-formaldehyde furan resin.Furthermore,the thermal strength can be improved at a temperature of higher than 550℃.

Investigation on Thermal and Dimensional Stability of Epoxy Resin In-Situ Modified by Cyanate Ester Resin and Polydimethylsiloxane

The thermal and dimensional stability of epoxy resin(EP)in-situ modified by cyanate ester(CE)and polydimethylsiloxane(PDMS)are investigated by means of experiments and numerical simulation.Thermal gravimetric analysis(TGA)and differential scanning calorimeter(DSC)are used to analyze the heat resistance of the modified EP.The dimensional stability is characterized by the volume shrinkage of the series PDMS/CE/EP obtained by the density method.The chemical structure of the PDMS/CE/EP is analyzed by Fourier transform infrared spectroscopy(FTIR).The results of TGA and DSC indicate that the thermal stability of PDMS/CE/EP decreases firstly and then increases with the increase in the amount of CE.The addition of PDMS shows a slight effect on the thermal stability.The 40%CE makes the blending system exhibit the lowest initial decomposition temperature,which reduces by 15.5%and 40.8%compared with pure EP and CE,respectively.The FTIR results suggested that the influence of CE on the thermal stability of the modified EP is mainly ascribed to the generation of oxazolidinone ring with low thermal stability and the increase in the triazine ring with high thermal stability.The volume shrinkage measurement results show that the introduction of CE and PDMS are both beneficial to the improvement of the dimensional stability of the blending systems.The in-situ addition of 80%CE shows the lowest volume shrinkage of6.11%.The thermal stress distribution of PDMS/CE/EP generated during the solidification process is simulated by the finite element analysis.The results suggested that the introduction of 80%CE into EP results in the lowest thermal stress in the blending system,which indicates that the system has the lowest volume shrinkage,which agrees well with the experimental results.

Toughness Effect of Graphene Oxide-Nano Silica on Thermal-Mechanical Performance of Epoxy Resin

A graphene oxide/nano-silica(GOS)hybrid was rapidly and easily synthesized using graphene oxide(GO)and nano-silica(nano-SiO_(2))as raw materials,and the synthesized GOS was used to improve the mechanical properties of epoxy resin(EP).The modified EP with different mass fractions of GOS(0,0.1%,0.2%,0.3%and 0.4%)were prepared and studied.The structure,thermal stability,mechanical properties,fracture toughness and failure morphology of the modified EP were analyzed.The results showed that the tensile strength of GOS modified EP increased from 40.6 MPa to 80.2 MPa compared with EP,the critical stress intensity factor of GOS modified EP increased by 65.9%from 0.82 MPa·m^(1/2)to 1.36 MPa·m^(1/2),indicating a significant enhancement in fracture toughness.In addition,failure morphology was observed by scanning electron microscopy(SEM)observation.The toughness mechanism of the modified EP was also discussed.Finally,the thermal stability of the modified EP was improved by the addition of GOS.Compared with neat EP,the initial thermal degradation temperature and glass transition temperature of GOS modified EP increased by 4.5℃and 10.3℃,respectively.

碳纤维/环氧树脂基复合材料增韧改性的研究进展

碳纤维/环氧树脂基复合材料(Carbon Fiber Reinforced Polymer,CFRP)因其高强度、高刚性和低密度等优异性能,在航空航天、汽车、船舶和风能等领域得到了广泛应用。然而,环氧树脂基体的固有脆性限制了CFRP的广泛应用。因此,如何提高其韧性成为研究的热点。综述了近年来碳纤维/环氧树脂基复合材料增韧改性的研究进展,重点介绍了树脂改性、界面改性及结构设计等方法,对未来研究方向进行了展望。

改性纳米氮化硼对纤维金属层板的性能影响

纤维金属层板是一种由金属薄板与纤维层依次交替铺叠而成,在一定的温度与压力下粘结固化形成的一种混合复合材料。因为其中有金属与纤维两种材料,因此它既有金属的富延展性、韧性强与导热性好等优点,又具有复合材料纤维的抗疲劳、耐高强度与低密度等特点。文章以提升环氧复合材料基体的拉伸与断裂韧性性能和改善FMLs的性能,尤其是冲击与弯曲性能为主要目的,采用向FMLs环氧树脂基体中添加纳米氮化硼(h-BN)的方法,来提升纤维金属层板的力学性能。先对氮化硼材料进行一系列的球磨改性处理,分成不同含量的组分依次加入环氧树脂基体中,确定用量最好的四组,再将这四组环氧树脂复合材料基体用湿法铺层的方法铺在铝薄板与碳纤维布之间,使用硫化机固化的方式制备FMLs试件,利用水切割技术切割成标准试样,并进行冲击与弯曲测试。实验结果表明,向FMLs的环氧树脂基体中添加一定量的纳米氮化硼对FMLs的性能有着积极的影响。

环氧树脂的亲水改性及固化特征研究

以环氧树脂E-51与二乙醇胺进行开环加成,在疏水环氧树脂分子中引入亲水基团,加酸成盐后得到环氧树脂水性体系。利用红外光谱和热失重对产物进行分析,研究了反应温度、反应时间等对反应产物的影响,最优反应温度为80℃,反应时间为3 h。此外,还对亲水改性环氧树脂的涂膜表干时间、附着力、硬度和柔韧性进行了研究,结果表明,亲水改性环氧树脂有良好的应用前景和价值。

可控ZnO阵列改性碳织物复合材料的制备及摩擦学性能研究

碳纤维表面光滑且具有惰性,削弱了其与树脂的界面黏结,进而限制了碳织物/树脂复合材料的应用前景。基于界面工程技术,采用预埋晶种层的方式诱导ZnO微纳米阵列在碳纤维表面均匀生长,并通过改变晶种层溶度优化ZnO阵列的形貌和分布,以强化纤维/基体的界面,从而提升复合材料的力学强度和摩擦学性能。结果表明:通过对纤维表面形貌分析,晶种层浓度对ZnO微纳米阵列形貌和分布有较大的影响;当浓度为15mmol/L时,均匀且细化的ZnO阵列生长在碳纤维表面,使纤维的表面能大幅度提高,促进了树脂充分浸润,提高了力学强度;与原始复合材料相比,改性复合材料的磨损率降低了约35%,表明ZnO阵列的引入能够明显提高复合材料的耐磨性。

IPDI改性水性醇酸乳液的制备及性能研究

水性醇酸涂料漆膜的硬度、光泽与耐水性较油性醇酸涂料差,改进这些性能对水性醇酸涂料的推广应用有重要意义。本研究以大豆油、季戊四醇及苯酐为原料,采用醇解法合成醇酸预聚体,并引入异佛尔酮二异氰酸酯(IPDI)改性,通过相反转法制成IPDI改性水性醇酸乳液。研究了IPDI用量、中和剂AMP-95用量、乳化工艺对水性醇酸乳液性能的影响。结果表明:当IPDI用量(以苯酐的质量计)为50%,AMP-95用量(以树脂的质量计)为0.6%,乳化剂用量(以树脂的质量计)为5%,搅拌速度为4000 r/min时,所制得的水性醇酸乳液漆膜硬度达2H,光泽为90.87,表干2 h,耐水性24 h无异常,漆膜综合性能表现良好。

水性环氧乳液/海泡石复合改性苯丙乳液涂层粘结性能研究

采用物理共混法制备水性环氧乳液/海泡石复合改性苯丙乳液涂层,探讨了苯丙-水性环氧乳液配比,三乙醇胺、填料及乳化沥青掺量对涂层粘结强度的影响,同时考察了复合涂层的抗渗性和耐高低温性。结果表明,当苯丙乳液与水性环氧乳液的有效质量比为1∶2,三乙醇胺、海泡石和乳化沥青掺量分别为2%、3%、5%时,复合涂层粘结强度为3.54MPa,与钢板间具有较好的相容性,且不透水性和耐高低温性优良。