磁流变胶泥的制备及其性能研究

发布时间：2018-10-26 21:53

【摘要】：磁流变材料作为一种磁场可控的智能材料主要包括磁流变液、磁流变弹性体、磁流变塑性体、磁流变脂等,其可应用于建筑、汽车、医疗、军事等领域的隔振缓冲设备中,但由于其存在的缺陷限制了其广泛应用。针对磁流变液沉降稳定性差、剪切屈服应力小,磁流变弹性体、磁流变塑性体可控范围窄,磁流变脂易产生分油、温度稳定性差等问题。本文以主要成分为高聚合度线性聚硅氧烷的弹性胶泥为载液,结合磁流变材料制备工艺,制备了一种新型磁流变材料——磁流变胶泥,并对其磁致机理、材料制备方法及基本性能、流变学特性、粘弹特性等进行了研究。具体工作如下:①分析了现有磁流变材料及其工程应用前景,针对现有磁流变材料在工程应用中存在的不足,提出了以主要成分为高聚合度线性聚硅氧烷的弹性胶泥为载液的新型磁流变材料——磁流变胶泥,阐述了本课题的研究意义及主要研究内容。②从磁流变胶泥的微结构出发,采用场致偶极子理论,建立了基于单链结构的磁致剪切应力模型,并假设链与磁场方向的夹角服从指数分布,得到磁致剪切应力的分析模型。结果表明:磁致剪切应力与可磁化颗粒的体积分数、磁场的平方成正比,与可磁化颗粒的磁化特性及分布情况等因素相关。当可磁化颗粒半径为1?m~5?m时,磁致剪切应力增长速度快,大于5?m后对剪切应力的影响较小。可将该模型用于磁流变胶泥制备过程中原材料的选取及实验现象的解释描述中。③分析了载液、可磁化颗粒、添加剂等的选取原则,结合弹性胶泥的合成工艺与磁流变材料的制备工艺,制备了12种磁流变胶泥样品。通过红外光谱测试、光学微结构观察、自然观测沉降率及磁化特性测试分析,结果表明:所制备的磁流变胶泥具有良好的分散性、无板结现象,剩磁及矫顽力小,经300天静置沉降率不超过5%。④采用MCR-301流变仪对磁流变胶泥的流变特性进行了测试,并采用H-B模型拟合了磁流变胶泥的本构关系及识别了其本构关系参数,结果表明H-B模型能较好的描述磁流变胶泥的本构关系。测试和分析了可磁化颗粒含量、外加磁场、载液、温度等对磁流变胶泥剪切应力的影响,结果表明可磁化颗粒含量、磁场、载液粘度的增大有助于提高剪切应力,而温度的升高使得剪切应力变小。此外,在剪切率200s-1,磁场为0~1T时20wcp60%的磁流变胶泥的剪切应力调节范围为14.1k Pa~128 k Pa。⑤在MCR-301流变仪振荡剪切模式下研究了磁流变胶泥的粘弹特性,分析了储能模量、损耗因子与应变、磁场、频率的关系。结果表明:20wcp20%的样品相对磁流变效应可达到1400%;增大磁场能拓宽线性粘弹性区,磁场为1T时的线性粘弹性区为0T时的20倍;在线性粘弹性区内,磁流变胶泥主要表现为弹性且储能模量与频率无关;在非线性粘弹性区内,磁流变胶泥主要表现为粘性且储能模量与频率近似成线性增长关系。
[Abstract]:As a kind of intelligent material controlled by magnetic field, Mr materials mainly include magnetorheological fluid, magnetorheological elastomer, magnetorheological plastic body, magnetorheological lipids and so on. They can be used in building, automobile, medical treatment, military and other fields of vibration isolation and buffer equipment. However, its wide application is limited by its defects. The problems such as poor settling stability of magnetorheological fluid, small shear yield stress, narrow controllable range of magneto-rheological elastomer, easy oil separation of magnetorheological lipids and poor temperature stability are pointed out. In this paper, a new type of magnetorheological material, magnetorheological slime, was prepared by using elastomeric slime with high degree of polymerization linear polysiloxane as carrier liquid. The preparation and basic properties, rheological and viscoelastic properties of the materials were studied. The main works are as follows: 1. The existing magnetorheological materials and their engineering application prospects are analyzed. A new type of magnetorheological material, magnetorheological slime, which is loaded with elastic slime with high degree of polymerization, is proposed. The research significance and main research contents of this subject are described. 2 starting from the microstructure of MRM, a new type of magnetorheological slime with high polymerization degree linear polysiloxane is proposed. Based on the theory of field-induced dipole, the magnetic-induced shear stress model based on single-chain structure is established, and the analytical model of magnetic-induced shear stress is obtained on the assumption that the angle between the chain and the magnetic field direction is exponentially distributed. The results show that the magnetically induced shear stress is directly proportional to the volume fraction of magnetized particles and the square of magnetic field, and is related to the magnetization characteristics and distribution of magnetized particles. When the radius of magnetized particles is 1?m~5?m, the growth rate of magnetostrictive shear stress is fast, and the effect of magnetization on shear stress is small when the magnetic particle radius is larger than 5 nm. The model can be applied to the selection of raw materials and the explanation and description of experimental phenomena during the preparation of magnetorheological cement. 3 the selection principles of carrier liquid, magnetized particles and additives are analyzed. Twelve kinds of magnetorheological mortar samples were prepared by combining the synthetic process of elastic slime and the preparation of magneto-rheological material. The results of infrared spectroscopy, optical microstructure observation, natural observation of sedimentation rate and magnetization characteristics show that the prepared magnetorheological cement has good dispersion, no plate junction, and low remanence and coercivity. The rheological properties of magnetorheological slime were tested by MCR-301 rheometer after 300 days of settling rate was not more than 5.4. The constitutive relation of MRM was fitted by H-B model and its constitutive parameters were identified. The results show that H-B model can describe the constitutive relation of magnetorheological slime. The effects of magnetizable particle content, applied magnetic field, carrier liquid and temperature on the shear stress of magnetorheological slime were measured and analyzed. The results show that the increase of magnetized particle content, magnetic field and viscosity of the liquid carrier can increase the shear stress. The shear stress decreases with the increase of temperature. In addition, when the shear rate is 200s-1 and the magnetic field is 0 ~ 1T, the shear stress adjustment range of 20wcp60% magnetorheological mortar is 14.1k Pa~128 k Pa.5. The viscoelastic properties of MRM are studied under the oscillatory shear mode of MCR-301 rheometer. The relationship between energy storage modulus, loss factor and strain, magnetic field and frequency is analyzed. The results show that the relative magnetorheological effect of 20wccp20% samples can reach 1 400 and the linear viscoelastic region can be widened by increasing the magnetic field, and the linear viscoelastic region at 1T is 20 times as high as that at 0T. In the linear viscoelastic region, the magnetorheological mortar is mainly elastic and the storage modulus is independent of frequency, while in the nonlinear viscoelastic region, the magnetorheological mortar is mainly viscous and the energy storage modulus increases linearly with the frequency.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB381

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