水或碱溶液浸泡对碳纤维增强乙烯基酯拉挤板材性能的影响
发布时间：2018-07-18 11:59
【摘要】：近年来,碳纤维增强高分子(CFRP)复合材料被广泛应用于土木工程结构的加固、修复或新建结构,由于在土木工程中环境复杂、结构服役寿命长,CFRP复合材料的耐久性能问题逐渐凸显,特别是在潮湿或碱性环境(如混凝土内部环境)下,CFRP复合材料的长期性能演化关系到FRP增强结长期服役的安全性。乙烯基酯树脂具有优异的耐水、耐化学腐蚀等特性,且由于粘度低,加工性能优于环氧树脂。因此,本文采用升温加速试验方法,研究乙烯基酯树脂与碳纤维增强乙烯基酯拉挤板材在水或强碱溶液浸泡条件下的性能演化及退化机理,该研究将促进高耐久性能CFRP复合材料的开发及其土木工程结构的应用。乙烯基酯树脂在固化过程中产生较大收缩;浸泡于水或强碱溶液其吸水符合两阶段水吸收行为;吸水导致树脂发生溶胀,在水浸泡下其溶胀应变远小于收缩应变,而碱液浸泡下溶胀应变大于收缩应变;树脂吸水后塑化明显,树脂酯键在水或强碱浸泡条件下发生水解,且强碱浸泡会加速树脂的水解反应;水、碱液浸泡使乙烯基酯树脂的力学性能发生退化,且碱液浸泡下树脂力学性能的破坏较水浸泡下的更为严重。乙烯基酯CFRP拉挤板材在水、碱液浸泡过程中的吸水也符合两阶段水吸收行为;树脂基体和碳纤维-树脂粘结界面吸收水分,且界面的吸水乙烯基酯CFRP起主要作用。短梁剪切强度和面内剪切强度结果表明,水或强碱溶液浸泡导致碳纤维-树脂的界面粘结性能发生不可逆退化,且碱加速界面粘结性能的退化。动态热力学性能测试结果和扫描电镜结果验证了界面粘结性能的退化。水、碱液浸泡使乙烯基酯CFRP拉挤板材的力学性能发生退化,且碱液浸泡加速树脂力学性能的退化,在浸泡后期抗拉强度和抗拉模量都趋于稳定值;在试验初期乙烯基酯CFRP拉挤板材抗拉强度由基体模量变化和界面变化共同决定,之后随着基体吸水达到稳定乙烯基酯CFRP拉挤板材内外模量差值不断减小,界面剪力同时随之减小,乙烯基酯CFRP拉挤板材抗拉强度将由受拉时纤维应力的均匀程度决定。VE具有优异的耐水、耐碱性能,但乙烯基酯CFRP拉挤板材的界面性能在水或碱浸泡下却快速退化,而其拉伸性能影响较小,为提高乙烯基酯CFRP板材的耐水或强碱溶液浸泡性能,需要着重研究如何提高碳纤维与乙烯基酯界面粘结性能,如开发适合乙烯基酯的碳纤维表面上浆处理剂。
[Abstract]:In recent years, carbon fiber reinforced polymer (CFRP) composites have been widely used in the reinforcement, repair or construction of civil engineering structures, due to the complex environment in civil engineering. The durability of CFRP composites with long service life is becoming more and more serious, especially in wet or alkaline environment (such as in concrete). The evolution of long-term performance of CFRP composites is related to the long-term service safety of FRP reinforced junctions. Vinyl ester resin is superior to epoxy resin because of its low viscosity and excellent resistance to water and chemical corrosion. Therefore, the properties evolution and degradation mechanism of vinyl ester resin and carbon fiber reinforced vinyl ester extruded sheet in water or strong alkali solution were studied by means of accelerated heating test. This study will promote the development of high durability CFRP composites and the application of civil engineering structures. The water absorption of vinyl ester resin in water or strong alkali solution accords with the two-stage water absorption behavior. The swelling strain of vinyl ester resin is much smaller than that of shrinkage strain when it is soaked in water. The swelling strain is larger than the shrinkage strain, the resin is plasticized obviously after absorbing water, the resin ester bond is hydrolyzed under the condition of water or strong alkali soaking, and the strong alkali soaking accelerates the hydrolysis reaction of the resin. The mechanical properties of vinyl ester resin were degraded by alkali soaking, and the destruction of mechanical properties of vinyl ester resin was more serious than that of water immersion. The water absorption of vinyl ester CFRP extruded sheet in water and alkali solution soaking also accords with the two-stage water absorption behavior; the resin matrix and carbon fiber resin bond interface absorbs water and the interface water absorption vinyl ester CFRP plays a major role. The results of shear strength and in-plane shear strength of short beam show that soaking in water or strong alkali solution leads to irreversible degradation of interfacial bond property of carbon fiber resin and alkali accelerates the degradation of interfacial bond property. The degradation of interfacial adhesion was verified by the dynamic thermodynamic properties and SEM results. The mechanical properties of vinyl ester CFRP extruded sheet were degraded by water and alkali soaking, and the mechanical properties of the resin were accelerated by alkali soaking. The tensile strength and tensile modulus of the resin tended to be stable at the later stage of soaking. At the beginning of the experiment, the tensile strength of vinyl ester CFRP pullout plate was determined by the change of matrix modulus and interface, and then the difference between internal and external modulus of vinyl ester CFRP sheet was decreased with the water absorption of the matrix reaching stable. The interfacial shear force decreases at the same time. The tensile strength of vinyl ester CFRP extruded sheet is determined by the uniformity of fiber stress when it is pulled. VE has excellent water resistance and alkali resistance. However, the interfacial properties of vinyl ester CFRP extruded sheets rapidly degenerate under water or alkali soaking, while the tensile properties of vinyl ester CFRP sheets have little effect. In order to improve the soaking performance of vinyl ester CFRP sheets in water or strong alkali solution, It is necessary to study how to improve the interfacial bond between carbon fiber and vinyl ester, such as the development of carbon fiber surface sizing agent suitable for vinyl ester.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332
本文编号：2131834
[Abstract]:In recent years, carbon fiber reinforced polymer (CFRP) composites have been widely used in the reinforcement, repair or construction of civil engineering structures, due to the complex environment in civil engineering. The durability of CFRP composites with long service life is becoming more and more serious, especially in wet or alkaline environment (such as in concrete). The evolution of long-term performance of CFRP composites is related to the long-term service safety of FRP reinforced junctions. Vinyl ester resin is superior to epoxy resin because of its low viscosity and excellent resistance to water and chemical corrosion. Therefore, the properties evolution and degradation mechanism of vinyl ester resin and carbon fiber reinforced vinyl ester extruded sheet in water or strong alkali solution were studied by means of accelerated heating test. This study will promote the development of high durability CFRP composites and the application of civil engineering structures. The water absorption of vinyl ester resin in water or strong alkali solution accords with the two-stage water absorption behavior. The swelling strain of vinyl ester resin is much smaller than that of shrinkage strain when it is soaked in water. The swelling strain is larger than the shrinkage strain, the resin is plasticized obviously after absorbing water, the resin ester bond is hydrolyzed under the condition of water or strong alkali soaking, and the strong alkali soaking accelerates the hydrolysis reaction of the resin. The mechanical properties of vinyl ester resin were degraded by alkali soaking, and the destruction of mechanical properties of vinyl ester resin was more serious than that of water immersion. The water absorption of vinyl ester CFRP extruded sheet in water and alkali solution soaking also accords with the two-stage water absorption behavior; the resin matrix and carbon fiber resin bond interface absorbs water and the interface water absorption vinyl ester CFRP plays a major role. The results of shear strength and in-plane shear strength of short beam show that soaking in water or strong alkali solution leads to irreversible degradation of interfacial bond property of carbon fiber resin and alkali accelerates the degradation of interfacial bond property. The degradation of interfacial adhesion was verified by the dynamic thermodynamic properties and SEM results. The mechanical properties of vinyl ester CFRP extruded sheet were degraded by water and alkali soaking, and the mechanical properties of the resin were accelerated by alkali soaking. The tensile strength and tensile modulus of the resin tended to be stable at the later stage of soaking. At the beginning of the experiment, the tensile strength of vinyl ester CFRP pullout plate was determined by the change of matrix modulus and interface, and then the difference between internal and external modulus of vinyl ester CFRP sheet was decreased with the water absorption of the matrix reaching stable. The interfacial shear force decreases at the same time. The tensile strength of vinyl ester CFRP extruded sheet is determined by the uniformity of fiber stress when it is pulled. VE has excellent water resistance and alkali resistance. However, the interfacial properties of vinyl ester CFRP extruded sheets rapidly degenerate under water or alkali soaking, while the tensile properties of vinyl ester CFRP sheets have little effect. In order to improve the soaking performance of vinyl ester CFRP sheets in water or strong alkali solution, It is necessary to study how to improve the interfacial bond between carbon fiber and vinyl ester, such as the development of carbon fiber surface sizing agent suitable for vinyl ester.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332
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相关硕士学位论文 前1条
1 赵鹏;碳纤维/不饱和聚酯树脂复合材料湿热老化行为研究[D];北京化工大学;2009年
，本文编号：2131834
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