本文關(guān)鍵詞：0-3型水泥基壓電復(fù)合材料的制備與改性　出處：《西安科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 水泥基壓電復(fù)合材料 壓電性能 介電性能 CNTs PVA

【摘要】：水泥基壓電復(fù)合材料(CPC)兼具感知與驅(qū)動功能,制備工藝簡單、生產(chǎn)成本低,與混凝土有著相似的物理化學(xué)性質(zhì),能克服傳統(tǒng)壓電材料與混凝土兼容性差、阻抗匹配度低的難題,使用該類壓電復(fù)合材料作為傳感器對混凝土結(jié)構(gòu)進(jìn)行健康監(jiān)測有望實(shí)現(xiàn)更高的精度,對該類材料的研究對土木工程實(shí)現(xiàn)智能化發(fā)展具有重要的意義。本文主要研究組分、成型工藝、極化工藝對CPC性能的影響,并探究了改性劑碳納米管(CNTs)和聚乙烯醇(PVA)對CPC性能的影響。通過X射線衍射儀(XRD)、紅外光譜(FTIR)、掃描電鏡(SEM)、透射電鏡(TEM)等手段對CPC進(jìn)行表征。研究組分對CPC性能的影響,結(jié)果表明:以硫鋁酸鹽水泥為基體的CPC的壓電壓應(yīng)變常數(shù)(d33)、壓電電壓常數(shù)(g33)和機(jī)電耦合系數(shù)(Kt)均要優(yōu)于以白水泥和普通硅酸鹽水泥為基體的CPC的值。CPC在水化初期,壓電性能不斷增加,10d后CPC的壓電性能趨于穩(wěn)定,水泥基體緊密包裹功能相顆粒。SEM分析表明功能相顆粒粒徑越大彼此間接觸率越高,大粒徑功能相顆粒的CPC具有更高的d33、g33和介電常數(shù)(εr),大粒徑功能相水泥基壓電復(fù)合材料聯(lián)結(jié)方式更近于并聯(lián)模型,但功能相顆粒粒徑超過126μm時(shí),壓電性能趨于平緩,且不利于機(jī)電耦合性能和機(jī)械品質(zhì)因數(shù)的提高;隨著功能相體積含量的增加,CPC的d33、g33和εr均不斷增大,SEM分析表明功能相含量越高,相互間的接觸率就越高,但功能相體積含量超過60%時(shí),機(jī)電耦合性能和機(jī)械品質(zhì)因數(shù)均有所降低。研究成型壓力和極化工藝對CPC性能的影響。結(jié)果表明:成型壓力越大,CPC的d33和εr均越大,但SEM分析表明過高的壓力會導(dǎo)致基體與功能相間產(chǎn)生層裂,從而使得材料的綜合性能下降。本文中最佳的成型壓力為90MPa。本文中最佳的極化工藝參數(shù)為:極化溫度為40A℃;極化電壓為4kV/mm;極化時(shí)間為15min。研究不同改性物對CPC性能的影響。結(jié)果表明:不同方法處理的CNTs的分散性不相同,TEM分析表明使用乳化劑OP-10處理的CNTs尺寸較大,分布也較均勻,綜合性能最優(yōu)。FTIR分析表明CNTs的摻入會與水泥之間產(chǎn)生鍵和,但不影響水泥的水化。隨著CNTs摻量的增加,CPC的d33、εr和Kt均增大,當(dāng)CNTs體積摻量達(dá)到0.7%時(shí),d33達(dá)到最大值42.3pC/N。CNTs的加入可以使得CPC的極化溫度降至為室溫。PVA摻入可以與水泥基體間產(chǎn)生鍵合,在0-3%PVA體積摻量范圍內(nèi),水泥基壓電復(fù)合材料的d33、g33和Kt值均不斷提高,氣孔率分析表明PVA摻入可以降低CPC的氣孔率而增大其致密度。在大于3%體積摻量時(shí),CPC綜合性能下降,SEM和紅外分析表明過多的PVA會在水泥和功能相顆粒表面形成一層片狀有機(jī)膜,這阻礙了水泥基體的水化,且對后期的極化不利。對水泥基壓電復(fù)合材料改性優(yōu)化可以提高該類材料對混凝土內(nèi)部結(jié)構(gòu)健康監(jiān)測的準(zhǔn)確率,增加其應(yīng)用可行性。這對減少大型土木工程事故率、降低人員傷亡率以及國家和社會財(cái)產(chǎn)損失具有重大意義。
[Abstract]:Cement-based piezoelectric composite (CPC) has both sensing and driving functions, simple preparation process, low production cost and similar physical and chemical properties to concrete. It can overcome the problems of poor compatibility between traditional piezoelectric materials and concrete and low impedance matching. Using this kind of piezoelectric composite materials as sensors for health monitoring of concrete structures is expected to achieve higher accuracy. The research on this kind of materials is of great significance to the intelligent development of civil engineering. This paper mainly studies the effect of molding technology and polarization process on the properties of CPC. The effects of modifiers such as carbon nanotubes (CNTs) and polyvinyl alcohol (PVA) on the properties of CPC were investigated. CPC was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of the study group on the properties of CPC was studied. The results show that the voltage strain constant of CPC based on sulphoaluminate cement is d33). The piezoelectric voltage constant g33) and the electromechanical coupling coefficient (Kt) are better than the values of CPC based on white cement and ordinary Portland cement. After 10 days, the piezoelectric properties of CPC tended to be stable, and the results showed that the larger the particle size of the functional phase was, the higher the contact rate between the particles was. The CPC with large particle size functional phase particle has higher D33 / G33 and dielectric constant (蔚 ~ (r)), and the connection mode of large particle size functional phase cement-based piezoelectric composite is more similar to that of parallel model. However, when the particle size of functional phase is more than 126 渭 m, the piezoelectric performance tends to be gentle, which is not conducive to the improvement of mechanical and electrical coupling performance and mechanical quality factor. SEM analysis shows that the higher the content of functional phase, the higher the contact rate of CPC. However, when the volume content of functional phase exceeds 60, the mechanical and electrical coupling performance and mechanical quality factor decrease. The influence of molding pressure and polarization process on the properties of CPC is studied. The results show that the higher the molding pressure is, the higher the forming pressure is. The larger the d33 and 蔚 r of CPC is, the higher the SEM analysis shows, the higher the pressure is, the spallation between the matrix and the functional phase. The optimum molding pressure in this paper is 90 MPA. The optimum process parameters in this paper are as follows: the polarization temperature is 40A 鈩，

本文編號：1400402