水或堿溶液浸泡對碳纖維增強乙烯基酯拉擠板材性能的影響
發(fā)布時間：2018-07-18 11:59
【摘要】：近年來,碳纖維增強高分子(CFRP)復合材料被廣泛應用于土木工程結構的加固、修復或新建結構,由于在土木工程中環(huán)境復雜、結構服役壽命長,CFRP復合材料的耐久性能問題逐漸凸顯,特別是在潮濕或堿性環(huán)境(如混凝土內部環(huán)境)下,CFRP復合材料的長期性能演化關系到FRP增強結長期服役的安全性。乙烯基酯樹脂具有優(yōu)異的耐水、耐化學腐蝕等特性,且由于粘度低,加工性能優(yōu)于環(huán)氧樹脂。因此,本文采用升溫加速試驗方法,研究乙烯基酯樹脂與碳纖維增強乙烯基酯拉擠板材在水或強堿溶液浸泡條件下的性能演化及退化機理,該研究將促進高耐久性能CFRP復合材料的開發(fā)及其土木工程結構的應用。乙烯基酯樹脂在固化過程中產生較大收縮;浸泡于水或強堿溶液其吸水符合兩階段水吸收行為;吸水導致樹脂發(fā)生溶脹,在水浸泡下其溶脹應變遠小于收縮應變,而堿液浸泡下溶脹應變大于收縮應變;樹脂吸水后塑化明顯,樹脂酯鍵在水或強堿浸泡條件下發(fā)生水解,且強堿浸泡會加速樹脂的水解反應;水、堿液浸泡使乙烯基酯樹脂的力學性能發(fā)生退化,且堿液浸泡下樹脂力學性能的破壞較水浸泡下的更為嚴重。乙烯基酯CFRP拉擠板材在水、堿液浸泡過程中的吸水也符合兩階段水吸收行為;樹脂基體和碳纖維-樹脂粘結界面吸收水分,且界面的吸水乙烯基酯CFRP起主要作用。短梁剪切強度和面內剪切強度結果表明,水或強堿溶液浸泡導致碳纖維-樹脂的界面粘結性能發(fā)生不可逆退化,且堿加速界面粘結性能的退化。動態(tài)熱力學性能測試結果和掃描電鏡結果驗證了界面粘結性能的退化。水、堿液浸泡使乙烯基酯CFRP拉擠板材的力學性能發(fā)生退化,且堿液浸泡加速樹脂力學性能的退化,在浸泡后期抗拉強度和抗拉模量都趨于穩(wěn)定值;在試驗初期乙烯基酯CFRP拉擠板材抗拉強度由基體模量變化和界面變化共同決定,之后隨著基體吸水達到穩(wěn)定乙烯基酯CFRP拉擠板材內外模量差值不斷減小,界面剪力同時隨之減小,乙烯基酯CFRP拉擠板材抗拉強度將由受拉時纖維應力的均勻程度決定。VE具有優(yōu)異的耐水、耐堿性能,但乙烯基酯CFRP拉擠板材的界面性能在水或堿浸泡下卻快速退化,而其拉伸性能影響較小,為提高乙烯基酯CFRP板材的耐水或強堿溶液浸泡性能,需要著重研究如何提高碳纖維與乙烯基酯界面粘結性能,如開發(fā)適合乙烯基酯的碳纖維表面上漿處理劑。
[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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB332
本文編號：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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB332
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