【摘要】：橡膠制品如汽車輪胎等的失效主要是由于裂紋的引發(fā)和擴(kuò)展導(dǎo)致的。從材料的角度來看,橡膠和填料是影響橡膠復(fù)合材料裂紋引發(fā)和擴(kuò)展的重要因素。本課題以天然橡膠(NR)為基體,重點(diǎn)探究了不同形狀系數(shù)的碳系填料對(duì)NR在準(zhǔn)靜態(tài)條件下的裂紋引發(fā)、擴(kuò)展,以及動(dòng)態(tài)條件下的裂紋擴(kuò)展性能的影響,并且分析了兩者之間的關(guān)聯(lián)性及其失效機(jī)理。填料主要包括球形炭黑(CB)、纖維狀碳納米管(CNTs)、片狀氧化石墨烯(GO)。采用J-積分測(cè)試表征了準(zhǔn)靜態(tài)條件下的抗裂紋引發(fā)和擴(kuò)展性能。J-積分測(cè)試得到臨界J-積分JIC和撕裂模量TR等參數(shù)。JIC表征材料的抗準(zhǔn)靜態(tài)裂紋引發(fā)性能,TR表征材料的抗準(zhǔn)靜態(tài)裂紋擴(kuò)展性能。采用動(dòng)態(tài)疲勞測(cè)試研究了材料的抗動(dòng)態(tài)裂紋擴(kuò)展性能。主要內(nèi)容包括以下四個(gè)部分:(1)研究了具有不同表面特性的CB和SiO_2雜化填料網(wǎng)絡(luò)對(duì)NR復(fù)合材料的抗準(zhǔn)靜態(tài)和動(dòng)態(tài)裂紋擴(kuò)展性能的影響。結(jié)果表明,隨SiO_2/CB質(zhì)量比的增加(SiO_2與CB的填料總量為5O份),JIC和TR均逐漸增加,表明抗準(zhǔn)靜態(tài)裂紋引發(fā)和擴(kuò)展能力得到提高。恒定應(yīng)變下的動(dòng)態(tài)疲勞測(cè)試表明,隨SiO_2/CB質(zhì)量比的增加,復(fù)合材料的動(dòng)態(tài)裂紋擴(kuò)展速率降低,疲勞壽命增加,這主要是由于恒定應(yīng)變下的應(yīng)變能密度隨Si02/CB質(zhì)量比的增加而降低。恒定應(yīng)變下的動(dòng)態(tài)疲勞的結(jié)果與準(zhǔn)靜態(tài)條件下的TR、JIC和應(yīng)變能密度等參數(shù)的結(jié)果一致。因此,準(zhǔn)靜態(tài)條件下的復(fù)合材料的TR、JIC和應(yīng)變能密度等參數(shù)可以用來預(yù)測(cè)恒定應(yīng)變下的動(dòng)態(tài)疲勞性能。(2)研究了纖維狀CNTs和球形CB雜化填料網(wǎng)絡(luò)對(duì)NR復(fù)合材料的準(zhǔn)靜態(tài)和動(dòng)態(tài)裂紋擴(kuò)展行為的影響。采用1份CNTs非等量替代3份CB的方式制備了具有相近硬度的CNTs/CB/NR復(fù)合材料。結(jié)果表明,CNTs和CB并用會(huì)對(duì)材料的抗準(zhǔn)靜態(tài)和動(dòng)態(tài)裂紋擴(kuò)展性能產(chǎn)生協(xié)同效應(yīng)。填充3份CNTs的復(fù)合材料表現(xiàn)出最優(yōu)異的抗疲勞性能。重點(diǎn)討論了準(zhǔn)靜態(tài)和動(dòng)態(tài)失效的協(xié)同機(jī)理和控制因素,例如CNTs的分散狀態(tài),雜化填料網(wǎng)絡(luò),應(yīng)變誘導(dǎo)結(jié)晶,應(yīng)變能密度以及粘彈性滯后損耗等因素。填充5份CNTs的NR表現(xiàn)出最弱的抗疲勞性能,原因是動(dòng)態(tài)疲勞過程中的嚴(yán)重的滯后生熱降低了材料的抗疲勞性能。(3)研究了片狀GO對(duì)NR復(fù)合材料的抗準(zhǔn)靜態(tài)和動(dòng)態(tài)裂紋擴(kuò)展性能的影響。通過膠乳共絮凝工藝制備了 GO增強(qiáng)的NR復(fù)合材料。膠乳共絮凝實(shí)現(xiàn)了 GO片層的完全剝離和在橡膠基體中的均勻分散。結(jié)果表明,隨GO含量的增加,GO/NR復(fù)合材料的力學(xué)性能、抗準(zhǔn)靜態(tài)裂紋引發(fā)和擴(kuò)展能力都明顯提高。GO具有比其它的傳統(tǒng)填料更高的補(bǔ)強(qiáng)效率。恒定應(yīng)變條件下,加入1份GO的NR復(fù)合材料具有最強(qiáng)的抗疲勞裂紋擴(kuò)展性能。填充3份和5份GO的復(fù)合材料的抗疲勞性能較弱,主要原因是它們具有較高的滯后損耗和應(yīng)變能密度。(4)對(duì)比研究了不同形狀系數(shù)的碳系填料對(duì)NR裂紋擴(kuò)展行為的影響,包括球形CB、纖維狀CNTs以及片層GO。通過機(jī)械共混法或膠乳共絮凝法制備了具有相等硬度的填料均勻分散的復(fù)合材料。結(jié)果表明,填充25份CB,3份CNTs和4份GO的復(fù)合材料具有相等的邵A硬度(硬度均為52)。填充25份CB的NR表現(xiàn)出最佳的抗準(zhǔn)靜態(tài)裂紋引發(fā)和擴(kuò)展性能以及抗疲勞性能。為了探究復(fù)合材料的失效機(jī)理,采用數(shù)字圖像相關(guān)技術(shù)分析了裂紋尖端應(yīng)變場(chǎng)的分布及應(yīng)變放大效應(yīng)。裂紋尖端應(yīng)變場(chǎng)分布表明,填充25份CB的NR表現(xiàn)出最高的應(yīng)變放大效應(yīng)和放大面積,這些都將有助于耗散掉局部輸入的能量,從而提高抗裂紋擴(kuò)展性能。填料不僅能夠提高橡膠材料的抗裂紋擴(kuò)展性能,也可以提高材料的導(dǎo)電性能。導(dǎo)電橡膠制品是功能化橡膠材料的一個(gè)非常重要的研究領(lǐng)域。如上所述,GO在提高橡膠材料抗疲勞性能方面的能力有限,而它的還原產(chǎn)物即還原氧化石墨烯(RGO)卻可以賦予橡膠材料優(yōu)異的導(dǎo)電性能。本課題分別采用GO “先還原”和“后還原”的方式,制備了導(dǎo)電石墨烯/NR復(fù)合材料,并且分別探究了它們?cè)趹?yīng)變敏感和溶劑敏感等領(lǐng)域的應(yīng)用。具體包括以下兩個(gè)部分:(1)采用明膠(Gel)作為界面穩(wěn)定劑和助還原劑,水合肼(HAA)作為主還原劑,制備得到了 Gel-HHA-RGO水分散液,避免了 GO在還原過程中的不可逆團(tuán)聚。Gel-HHA-RGO片層在堿性環(huán)境中表現(xiàn)出優(yōu)異的膠體分散性和穩(wěn)定性。通過水相溶液鑄膜法制備了具有結(jié)構(gòu)規(guī)整的石墨烯隔離網(wǎng)絡(luò)的Gel-HHA-RGO/NR復(fù)合材料。隨RGO含量的增加,復(fù)合材料的拉伸模量和動(dòng)態(tài)儲(chǔ)能模量提高了若干數(shù)量級(jí)。同時(shí),RGO隔離網(wǎng)絡(luò)降低了材料的導(dǎo)電閾滲值(0.21 vol%),提高了材料的電導(dǎo)率。應(yīng)變敏感性測(cè)試表明,具有隔離網(wǎng)絡(luò)結(jié)構(gòu)的RGO/NR復(fù)合材料表現(xiàn)出優(yōu)異的應(yīng)變敏感性和重復(fù)性,可作為檢測(cè)人體關(guān)節(jié)循環(huán)運(yùn)動(dòng)的傳感器。(2)吸附到RGO上的界面改性劑會(huì)降低RGO的導(dǎo)電性能。通過將GO水分散液與NR膠乳混合,水相溶液鑄模以及原位氫碘酸(HI)還原等一系列簡單工藝,制備出具有三維連續(xù)石墨烯隔離網(wǎng)絡(luò)的HI-RGO/NR復(fù)合材料,避免了表面改性劑的使用,同時(shí)簡化了制備工藝。HI-RGO/NR表現(xiàn)出較低的導(dǎo)電閾滲值(0.31 vol%)和較高的電導(dǎo)率。當(dāng)填充5.00 vol%的RGO時(shí),材料的電導(dǎo)率高達(dá)49.3 S/m。當(dāng)把HI-RGO/NR置于有機(jī)溶劑中時(shí),NR基體會(huì)發(fā)生溶脹。通過檢測(cè)電阻隨時(shí)間的變化,我們研究了材料的溶劑敏感性能。HI-RGO/NR對(duì)有機(jī)溶劑表現(xiàn)出非常敏感的刺激響應(yīng),并且對(duì)不同的有機(jī)溶劑表現(xiàn)出不同的敏感響應(yīng)。由于溶劑揮發(fā)之后連續(xù)RGO網(wǎng)絡(luò)的重新構(gòu)筑,該復(fù)合材料表現(xiàn)出優(yōu)異的溶劑敏感重復(fù)性。
[Abstract]:The failure of rubber products, such as automobile tires, is mainly due to the initiation and expansion of cracks. From the point of view of material, rubber and filler is an important factor affecting the crack initiation and expansion of rubber composites. This topic is based on natural rubber (NR) as the matrix, focusing on the quasi static strip of NR in the carbon system with different shape coefficients. The effect of crack initiation, expansion and crack propagation under dynamic conditions, and the correlation and failure mechanism between the two are analyzed. The filler mainly includes spherical carbon black (CB), fibrous carbon nanotube (CNTs), and flaky graphene oxide (GO). The J- integral test is used to characterize the crack initiation and expansion under quasi-static conditions. The spreading performance.J- integral test obtains the critical J- integral JIC and the tearing modulus TR to characterize the anti quasi-static crack initiation properties, and TR characterizing the quasi static crack propagation properties. Dynamic fatigue testing is used to study the dynamic crack propagation properties of the material. The main contents include the following four parts: (1) the study has not been done. The effect of CB and SiO_2 hybrid packing network with the same surface properties on the quasi static and dynamic crack propagation properties of NR composites shows that JIC and TR increase gradually with the increase of the mass ratio of SiO_2/CB (the total amount of SiO_2 and CB is 5O), indicating that the ability to induce and expand the quasi static crack initiation and expansion. The fatigue test shows that with the increase of the mass ratio of SiO_2/CB, the dynamic crack propagation rate of the composite decreases and the fatigue life increases, which is mainly due to the decrease of the strain energy density under the constant strain with the increase of the mass ratio of Si02/CB. The results of dynamic fatigue under constant strain and the parameters of TR, JIC and strain energy density under quasi static condition The results are consistent. Therefore, the parameters such as TR, JIC and strain energy density in quasi-static composite materials can be used to predict the dynamic fatigue performance under constant strain. (2) the effect of fiber like CNTs and spherical CB hybrid packing network on the quasi static and dynamic crack propagation behavior of NR composites is studied. 1 CNTs non equal quantities are used instead of 3. The CNTs/CB/NR composites with similar hardness are prepared by CB. The results show that CNTs and CB can produce synergistic effects on the quasi static and dynamic crack propagation properties of the materials. The composite materials filled with 3 portions of CNTs exhibit the most excellent fatigue resistance. The synergistic mechanism and control of quasi static and dynamic failure are discussed. Factors such as the dispersion state of CNTs, hybrid packing network, strain induced crystallization, strain energy density and viscoelastic hysteresis loss. The NR filled with 5 parts CNTs shows the weakest anti fatigue properties, the reason is that the severe hysteresis heat in the dynamic fatigue process reduces the fatigue resistance of the material. (3) the study of the sheet GO to NR composite GO reinforced NR composites were prepared by the latex co flocculation process. The total peeling of the GO lamellae and the uniform dispersion in the rubber matrix were realized by latex flocculation process. The results showed that the mechanical properties of the GO/NR composite material with the increase of the content of GO, the resistance to quasi-static crack initiation and the resistance to quasi-static cracks were caused by the increase of the content of the GO/NR. The expansion ability obviously improves the reinforcing efficiency of.GO than other traditional fillers. Under constant strain conditions, 1 GO NR composites have the strongest fatigue crack propagation properties. The fatigue resistance of the composites filled with 3 and 5 copies of GO is weak, mainly due to their high hysteresis loss and strain energy density. Degree. (4) the effects of carbon fillers with different shape coefficients on the crack propagation behavior of NR were investigated, including spherical CB, fibrous CNTs and lamellar GO. by mechanical blending or latex co flocculation. The results showed that 25 CB, 3 CNTs and 4 GO composites were filled. Equal shore A hardness (hardness is 52). NR with 25 portions of CB shows the best anti static crack initiation and propagation properties and fatigue resistance. In order to explore the failure mechanism of the composite material, the distribution of strain field and strain amplification effect at the crack tip are analyzed by digital image correlation technique. The strain field distribution table at the crack tip is analyzed. It is clear that the filling of 25 CB NR shows the highest strain amplification effect and enlargement area, which will help to dissipate the local input energy and improve the crack propagation resistance. The filler can not only improve the crack growth resistance of the rubber material, but also improve the conductive properties of the material. The conductive rubber product is a functional rubber material. GO is a very important field of research. As mentioned above, the ability to improve the fatigue resistance of rubber materials is limited, and its reduction product, the reduction of graphene oxide (RGO), can give the rubber material excellent electrical conductivity. This topic has been prepared by GO "first reduction" and "after reduction", respectively, to prepare the tourmaline. The application of the /NR composites in strain sensitivity and solvent sensitivity are investigated. The following two parts are included: (1) using gelatin (Gel) as an interface stabilizer and reducing agent, hydrazine (HAA) as the main reducing agent, the Gel-HHA-RGO water dispersions are prepared to avoid the inability of GO in the process of reduction. The reverse reunion.Gel-HHA-RGO layer shows excellent colloidal dispersion and stability in the alkaline environment. Gel-HHA-RGO/NR composites with structured graphene isolation network are prepared by aqueous solution casting film method. With the increase of RGO content, the tensile modulus and dynamic energy storage modulus of the composite are increased by a number of orders of magnitude. The RGO isolation network reduces the conductivity of the material (0.21 vol%) and improves the conductivity of the material. The strain sensitivity test shows that the RGO/NR composite with isolated network structure shows excellent strain sensitivity and repeatability, and can be used as a sensor for detecting the movement of human joints. (2) the interfacial modifier adsorbed on RGO The conductivity of RGO can be reduced. By mixing GO water dispersions with NR latex, water phase solution casting and in situ hydroiodic acid (HI) reduction, a series of HI-RGO/NR composites with three dimensional continuous graphene isolation network are prepared, avoiding the use of surface modifier and simplifying the preparation process.HI-RGO/NR. Low conductivity threshold (0.31 vol%) and higher conductivity. When filled with 5 vol% RGO, the conductivity of the material is up to 49.3 S/m.. When HI-RGO/NR is placed in the organic solvent, the NR matrix will dissolve. By detecting the change of resistance with time, we have studied the solubility of the solution sensitivity of the material.HI-RGO/NR to the organic solvent. Sensitive response and sensitive response to different organic solvents. The composite exhibits excellent solvent sensitivity repeatability due to the restructure of continuous RGO networks after solvent volatilization.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB332

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相關(guān)期刊論文 前1條

1 張立群,吳友平,王益慶,王一中,張慧峰,余鼎聲,賀建蕓;橡膠的納米增強(qiáng)及納米復(fù)合技術(shù)[J];合成橡膠工業(yè);2000年02期

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本文編號(hào)：2139313