超临界正丁醇对回收碳纤维复合材料的降解及表征

采用响应面分析方法设计超临界正丁醇降解废弃的碳纤维/环氧树脂(CF/EP)复合材料降解实验,用以回收碳纤维.通过Design-Expert V8.0建立环氧树脂降解率和工艺参数之间的数学模型,获得了最优工艺参数;通过图形优化研究了工艺参数对环氧树脂基体降解率的影响规律;通过场发射电子扫描显微镜、原子力显微镜、X射线光电子能谱仪、显微共焦激光拉曼光谱仪及单丝拉伸等分析最优工艺参数下回收的碳纤维的表面形貌、表面化学、石墨化程度及力学性能.结果表明,建立的数学模型拟合误差范围为±5.5%,实现了回收工艺参数的预估;单因素对环氧树脂基体降解率的影响程度为:反应温度保温时间添加剂浓度正丁醇含量;最优工艺参数为:反应温度330℃,保温时间60 min,添加剂浓度0.0538 mol/L,投料比0.024g/mL.回收的碳纤维表面无残留树脂,没有发生明显的石墨化,且表面平均粗糙度与原碳纤维相近;与原始碳纤维相比,回收的碳纤维的拉伸强度约为原碳纤维的93.58%,杨氏模量约为原碳纤维的94.87%.     

聚酰胺酸齐聚物改性环氧树脂

以3,3′,4,4′-二苯醚四羧酸二酐和4,4′-二氨基二苯醚为原料合成了以三聚体为主的聚酰胺酸齐聚物(PAA-n)。通过红外光谱、差示扫描量热分析、电喷雾质谱对其进行了表征。用PAA-n作为环氧树脂的反应性改性剂,研究了PAA-n改性环氧树脂的热性能和力学性能。结果表明:合成产物为目标产物,与环氧树脂有很好的化学反应性和相容性,在合适的配比和固化机制下,改性后树脂体系的热性能有所改善,力学性能也有较大的提高。     

Influence of Epoxy Resin Treatment on the Mechanical and Tribological Properties of Hemp-Fiber-Reinforced Plant-Derived Polyamide 1010 Biomass Composites

In this study, we investigated the influence of epoxy resin treatment on the mechanical and tribological properties of hemp fiber (HF)-reinforced plant-derived polyamide 1010 (PA1010) biomass composites. HFs were surface-treated using four types of surface treatment methods: (a) alkaline treatment using sodium chlorite (NaClO₂) solution, (b) surface treatment using epoxy resin (EP) solution after NaClO₂ alkaline treatment, (c) surface treatment using an ureidosilane coupling agent after NaClO₂ alkaline treatment (NaClO₂ + A-1160), and (d) surface treatment using epoxy resin solution after the (c) surface treatment (NaClO₂ + A-1160 + EP). The HF/PA1010 biomass composites were extruded using a twin-screw extruder and injection-molded. Their mechanical properties, such as tensile, bending, and dynamic mechanical properties, and tribological properties were evaluated by the ring-on-plate-type sliding wear test. The strength, modulus, specific wear rate, and limiting pv value of HF/PA1010 biomass composites improved with surface treatment using epoxy resin (NaClO₂ + A-1160 + EP). In particular, the bending modulus of NaClO₂ + A-1160 + EP improved by 48% more than that of NaClO₂, and the specific wear rate of NaClO₂ + A-1160 + EP was one-third that of NaClO₂. This may be attributed to the change in the internal microstructure of the composites, such as the interfacial interaction between HF and PA1010 and fiber dispersion. As a result, the mode of friction and wear mechanism of these biomass composites also changed.     

亚临界水介质回收酸酐固化环氧树脂/碳纤维复合材料

研究了不同添加剂对碳纤维增强酸酐固化环氧树脂复合材料在亚临界水中降解的影响,通过IR、GC-MS等分析,确定了环氧树脂的分解机理主要为酯键的断裂。 结果表明,KOH与苯酚对酸酐固化环氧树脂的分解没有协同效应,碱性物质更有利于酯键的断裂。 甲基四氢邻苯二甲酸酐固化的环氧树脂增强碳纤维复合材料在反应温度为250 ℃、反应时间为60 min、KOH浓度为0.2 mol/L时可完全分解,回收碳纤维的拉伸强度和表面形貌未受影响。     

超临界流体回收碳纤维树脂复合材料

碳纤维树脂复合材料回收再利用是碳纤维产业可持续发展的重要一环,因此受到学术界及产业界的广泛关注。 超临界流体回收碳纤维方法是一种高效、清洁,并且对碳纤维性能损伤较小的回收方法。 本文回顾了超临界流体回收碳纤维树脂复合材料研究进展,系统讨论超临界体系、反应条件、催化剂等对树脂降解率、回收碳纤维性能的影响,并对超临界流体回收碳纤维树脂复合材料的未来发展进行了展望。     

Glass Transition Temperature Depression at the Percolation Threshold in Carbon Nanotube–Epoxy Resin and Polypyrrole–Epoxy Resin Composites

Summary: The glass transition temperatures of conducting composites, obtained by blending carbon nanotubes (CNTs) or polypyrrole (PPy) particles with epoxy resin, were investigated by using both differential scanning calorimetry (DSC) and dynamical mechanical thermal analysis (DMTA). For both composites, dc and ac conductivity measurements revealed an electrical percolation threshold at which the glass transition temperature and mechanical modulus of the composites pass through a minimum.

DC conductivity, σ_dc, as a function of the conducting filler concentration of the CNT– (▪) and PPy– (○) epoxy resin composites.     

聚丙撑碳酸酯／环氧树脂体系的力学性能

研究了聚丙撑碳酸酯／环氧树酯固化产物的动态力学性能和力学性能，考察了ＰＰＣ的分子量、含量对力学谱和力学性能的影响．结果表明，随ＰＰＣ含量增加，ｔａｎδ半峰宽增加，ＰＰＣ含量在２０～３０份时力学性能达最佳值，ＰＰＣ的分子量对力学性能的影响不大，但对动态力学和相区尺寸稍有影响。     

碳纳米管改性环氧树脂的导热和阻燃性能

以双酚A二缩水甘油醚(DGEBA)环氧树脂(Epoxy Resin,EP)为基体、甲基六氢苯酐(MHHPA)为固化剂、以多壁碳纳米管(MWCNTs)为添加剂制备了环氧树脂/碳纳米管纳米复合材料。通过对微观结构、玻璃化转变温度(Tg)、热失重、热导率和锥形量热测试结果分析,研究了质量分数少于1.5%的MWCNTs对环氧树脂的导热和阻燃性能影响,结果表明,MWCNTs质量分数为1.5%时,复合材料发生团聚;纳米复合材料随着MWCNTs质量分数的增加Tg值先增加后降低;失重5%时,对应的温度先增加后降低,残炭量增加;样品的热导率呈现先升高后降低的趋势,当MWCNTs质量分数为1%时,复合材料的热导率最大;MWCNTs加入后环氧树脂的总释热量减少,释烟量增加,阻燃性得到一定程度的提高。     

液体橡胶增韧环氧树脂/咪唑体系的形态与力学性能

液体橡胶增韧环氧树脂/咪唑体系的形态与力学性能;CTBN;HTBN; 增韧环氧树脂;形态结构;力学性能     

碳纤维三向织物/环氧树脂复合材料的制备与力学性能

选择不同纱线间距[即二经(纬)纱之间的中心距]尺寸的碳纤维三向织物,采用热压成型技术制备了碳纤维三向织物/环氧树脂复合材料.研究了纱线间距及样品裁剪角度等对力学性能的影响,并与碳纤维二向织物/环氧树脂复合材料的力学性能进行对比.结果表明,随着纱线间距尺寸从2 mm增加到6 mm,0°方向断裂强度从221. 7 MPa下降到148. 1 MPa,撕裂强力从1000 N下降到600 N; 90°方向断裂强度从50. 0MPa下降到22. 1 MPa,撕裂强力从330 N下降到100 N;顶破强力从424 N下降到216 N.这些力学性能的逐渐降低是单位面积的碳纤维增强体含量减少和织物的孔洞增大共同作用的结果.纱线间距为2 mm的碳纤维三向织物复合材料在0°(以纬纱为基准),30°,45°,60°和90°方向的断裂强度分别为221. 7,48. 5,44. 3,227. 7和50. 0 MPa,即断裂强度在0°和60°方向大于在30°,45°及90°方向.由三向织物的编织原理可知,0°与60°方向完全相同,因此其断裂强度相似,且样品中有一组纱线与外加载荷平行,对形变破坏具有一定的约束作用,而...     

Determination of Water Diffusion Coefficients and Dynamics in Adhesive/ Carbon Fiber Reinforced Epoxy Resin Composite Joints

To determinate the water diffusion coefficients and dynamics in adhesive/carbon fiber reinforced epoxy resin composite joints,energy dispersive X-ray spectroscopy analysis(EDX)is used to establish the content change of oxygen in the adhesive in adhesive/carbon fiber reinforced epoxy resin composite joints.As water is made up of oxygen and hydrogen,the water diffusion coefficients and dynamics in adhesive/carbon fiber reinforced epoxy resin composite joints can be obtained from the change in the content of oxygen in the adhesive during humidity aging,via EDX analysis.The authors have calculated the water diffusion coefficients and dynamics in the adhesive/carbon fiber reinforced epoxy resin composite joints with the aid of both energy dispersive X-ray spectroscopy and elemental analysis.The determined results with EDX analysis are almost the same as those determined with elemental analysis and the results also show that the durability of the adhesive/carbon fiber reinforced epoxy resin composite joints subjected to silane coupling agent treatment is better than those subjected to sand paper burnishing treatment and chemical oxidation treatment.     

碳纳米管及碳纤维增强环氧树脂复合材料研究进展

碳纳米管与碳纤维具有优异的力学、电学等性能,广泛用做复合材料增强体,但目前碳纳米管/碳纤维/环氧树脂复合材料的研究具有一定的局限性,只考虑了两相材料间的作用,即仅对单一相进行处理而忽略了另一相的改性。本文从碳纳米管/碳纤维协同增强环氧树脂基体复合材料的思路入手,结合自己的研究成果,综述了国内外相关研究进展。从研究结果可以看出,将三相材料之间完全有效地联系起来,发挥三者间的协同效应,复合材料的性能可以发生质的飞跃。     

Ethylene-Octene Copolymer-Nanosilica Nanocomposites: Effects of Epoxy Resin Functionalized Nanosilica on Morphology,Mechanical, Dynamic Mechanical and Thermal Properties

A comparative study of the structural, thermal, mechanical and thermomechanical properties of ethylene-octene copolymer 1

1 Ethylene-octene copolymer is produced using Dow's INSITETM ™ constrained geometry catalyst and process technology. ENGAGE the trade name of this copolymer.

(mPE) 2

2 This copolymer will be represented as mPE .

nanocomposites synthesized with pure nanosilica (NS) and nanosilica-functionalized with diglycidyl ether of bisphenol-A (ENS) has been reported. These nanocomposites were prepared using “melt mixing” method at a constant loading level of 2.5 wt. %. The effects of pure nanosilica (NS) and epoxy resin-functionalized-nanosilica (ENS) on the above mentioned properties of ethylene-octene copolymer were analyzed by wide-angle-x-ray diffractometer (WAXD), transmission electron microscope (TEM), thermo gravimetric analyzer (TGA), differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA) and scanning electron microscope (SEM). TEM studies have shown a better dispersion of nanoparticles in case of ethylene-octene copolymer-epoxy resin-functionalized-nanosilica nanocomposite (mPE-ENS) than that of ethylene-octene copolymer-nanosilica nanocomposite (mPE-NS). The tensile tests show that organic modification of nanosilica particles brings up an appreciable increase in yield strength, ultimate tensile strength and elongation at break of the polymer. DMA studies have shown an increase in the storage modulus and glass transition temperature for mPE-ENS with respect to mPE-NS. Further, the TGA results have shown a higher thermal stability for mPE-ENS in comparison to mPE-NS.     

反应性聚碳酸酯/环氧树脂体系的玻璃化转变行为及力学性能

增韧;反应性聚碳酸酯/环氧树脂体系的玻璃化转变行为及力学性能     

环氧树脂/聚碳酸酯固化共混物的结构及性能

相结构;酯交换反应;力学性能;环氧树脂/聚碳酸酯固化共混物的结构及性能     

Thermal Degradation of Tetrafunctional/Phenol Novalac Epoxy Mixture Cured with a Diamine

The effect of thermal degradation on the mechanical behaviour of a system containing both tetraglycidyl-4-4′-diaminodiphenylmethane (TGDDM) and a multifunctional novolac glycidyl ether (EPN) resins, cured with 4,4′-diaminodiphenylsulphone (DDS) has been studied using dynamic mechanical analysis (DMA) and tensile tests. Different curing paths using the isothermal time-temperature-transformation (TTT) diagram for this system were designed, obtaining thermosetting materials with different conversions. The influences of the degree of cure and of the aging temperature were also studied. The results showed different trends in the dynamic mechanical properties and an increase in the stiffness of the material with increasing aging time. Changes were faster and more intense with the higher temperature. This revised version was published online in August 2006 with corrections to the Cover Date.     

环氧树脂基多孔光学增透膜的制备及其性能研究

利用低分子量环氧树脂(DGEBA)在固化后和与之共混的聚氯乙烯(PVC)之间产生的相分离,用丁酮抽提其中的PVC组分,制备了环氧树脂基多孔增透膜。测试结果表明,当mDOEBA／mPVC=30／70、膜厚为110nm时,增透膜的透过率最高,达96％以上。薄膜在水或甲苯中煮沸不发生收缩、脱落,表现良好的粘附力和机械强度。     

Efficient Use of Carbon Fibers as Heating Elements for Curing of Epoxy Matrix Composites

The aim of this study is to achieve a fully cured thermoset matrix that is heated by a direct electric current passing through the reinforcement fibers i.e., the Joule heating effect. Two types of fibers were used as heating elements for curing the epoxy resins. Kanthal resistance fibers were used as reference heating elements and subsequently, they were replaced by a Torayca Carbon Tow of the same radius. The specimens were cured by the heat produced by a direct electric current passing through the fibers and achieving temperatures of 50 °C and 70 °C. Specimens cured in a conventional oven were also manufactured, to compare the resistance heating method to the conventional one. Next, all specimens were mechanically characterized in a quasi-static three-point bending mode of loading and experimental results were compared to derive useful conclusions concerning the applicability of the technique to polymer/composite materials mass production. Finally, a preliminary economical study concerning power consumption needed for the application of both the traditional oven curing and the carbon fibers heating elements use for the manufacturing of the same amounts of materials is presented, showing a maximum financial benefit that can be achieved, on the order of 68%.     

FTIR法研究环氧树脂固化反应动力学

用傅里叶红外光谱（ＦＴＩＲ）法研究了双酚Ｓ环氧树脂和甲溴双酚Ａ环氧树脂分别与二胺基二苯砜在恒温条件下的固化反应动力学,得出了各反应的表观活化能。