【作者】 马金焕；

【导师】 黄龙男； 王新波；

【作者基本信息】 哈尔滨工业大学 ， 材料学， 2010， 硕士

【摘要】 碳纤维增强复合材料（CFRP）具有高模量、耐热性能优良、质量轻、高强度等优异的性能，在航空航天、汽车、造船、体育休闲等制品中的应用日益广泛。随着需求量的增加，其废弃物也逐年增加，给环境造成了严重的负担。环氧树脂是CFRP制品中应用最多的基体，由于其固化后形成交联的三维网状结构，采用常规化学溶剂无法将其溶解或加热熔融，因此，采用合理的处理方法对CFRP制品废弃物进行回收已经成为一个重要的研究课题。本文在充分归纳目前国内外对CFRP制品废弃物回收的研究现状的基础上，制定了以硝酸为介质，采用常压溶剂法解聚胺类固化环氧树脂及其复合材料的研究方案。研究了不同解聚条件（反应温度、硝酸浓度、反应时间）对解聚效果的影响，并以解聚率和回收碳纤维的强度保留率为指标，确定了最佳的解聚条件；对解聚产物进行红外和SEM分析，揭示了解聚反应的机理；根据反应速率的测定方法，对其反应动力学进行了研究，建立了反应的动力学模型。研究结果表明，树脂的解聚率随着反应温度、硝酸浓度和反应时间的增加而增大，其中硝酸浓度是最重要的影响因素。在95℃8mol/L硝酸分解液的作用下，23h后复合材料中树脂的解聚率达99.18%，热重分析和扫描电子显微镜观察结果均表明回收碳纤维的表面附着的树脂很少、有轻微的氧化刻蚀；回收碳纤维的单丝强度有一定的损失，但是其保留率仍可达到80%以上，能够对其进行回收和再利用。测定了胺类固化环氧树脂在硝酸介质中的宏观反应速率和反应的活化能，建立了其反应的动力学模型。通过恒定硝酸浓度法可以显著提高树脂的解聚速率，5h树脂即可基本解聚完全。采用红外光谱仪对解聚产物进行了定性分析，提出了胺类固化环氧树脂在硝酸介质中的解聚机理。红外分析表明，1112cm-1处峰明显降低，同时在解聚产物中出现了1537cm-1的苯环硝基峰。这说明在硝酸介质中固化环氧树脂的网状结构遭到了破坏，C-N键断裂同时引起了苯环的硝化。更多还原

【Abstract】 Carbon fiber reinforced composites (CFRP) have been widely applied in fields ofaerospace, automobile, shipbuilding, and sports due to their excellent properties suchas high modulus, good thermal resistance, lightweight and high-strength. However,the high output of CFRP to meet the rising market demands has produced a greatamount of CFRP wastes, which would bring serious burden to the environment.Epoxy resin (EP) are the greatest consumption in production of CFRP. But they weredifficult to be dissolved with conventional solvent or melted due to theirthree-dimensional network structure after cured. Therefore it has become animportant topic proposing a perfect recovery method to dispose the CFRP wastes.In this article, the existing and potential technologies used for the recycling ofCFRP wastes have been introduced fully. Based on this, the research program whichepoxy resin cured with amine and CFRP were degraded in nitric acid using solventrecovery method under atmospheric pressure was established. The effects ofdifferent decomposed conditions such as reaction time, the nitric acid concentrationand reaction temperature on degradation efficiency were discussed. The optimaldecomposed conditions were assessed with degradation rate and monofilamentstrength retention of recycling carbon fibers as indexes. Frontier Transform InfraredSpectroscopy (FTIR) and Scanning Electron Microscope (SEM) were employed toanalyze decomposition products and depolymerization mechanism was revealed.Based on the determination of reaction rate, the reaction kinetics was studied and thekinetic model was initially established.The results suggested that the degradation rate of resin was increased withreaction temperature, nitric acid concentration and reaction time increasing, of whichthe concentration was the most important factors. The degradation rate of resin inCFRP reached 99.18% after 23 hours in 8mol/L nitric acid at 95 degrees Celsius.Differential thermogravimetric (DTG) and Scanning Electron Microscope (SEM)analysis indicated that the surface of recycling carbon fibers were relatively pure, theresin content was little, and slight oxidation etching on the surface. Themonofilament strength of recycling carbon fiber was reduced to a certain extent, butthe retention was still up 80% which can be used for recycling and reuse.Macroscopic reaction rate and activation energy were determined and the kinetic model was established. The degradation rate increased obviously by controllingnitric acid concentration with constant and resin decomposed completely after 5hours. The degradation products were analyzed by FTIR and the depolymerizationmechanism of epoxy resin cured with amine in nitric acid was proposed. The resultsshowed that the peak of C-N bond (1112cm-1) reduced sharply and peak ofnitro-benzene (1537 cm-1) appeared in degradation products. This demonstrated thenetwork structure of cured epoxy resin was destroyed in nitric acid, C-N bonds werecleaved and the original resin was nitrated.更多还原