水泥基泡沫材料的制备与性能优化

发布时间：2018-09-18 15:01

【摘要】：随着我国墙体材料改革与建筑节能政策的强制实施,推动了建筑保温材料的快速发展。传统有机保温隔热材料虽然隔热性能好、质轻和价格便宜,但是易燃,且燃烧生成有毒气体等缺陷,使得建筑节能和防火之间的矛盾不断加剧。作为理想的替代品,无机发泡绝热材料因其安全性高的突出优点而倍受青睐。但目前用于外墙的无机发泡绝热材料仍存在着容重大,易吸水,而且导热系数偏大等问题。因此,制备出一种低导热系数、憎水、轻质高强等综合性能优异且制备工艺简单的无机泡沫绝热材料是解决这一矛盾的有效途径。本研究采用实验测试与理论分析相结合的研究方法,运用单因素与多因素控制变量法分别确定了发泡剂种类及掺量、水灰比、稳泡剂等外加剂,然后针对不同发泡工艺进行了探索,最终在适合的发泡工艺下制备了水泥基泡沫绝热材料,并对制品的强度、表观密度、孔隙率、吸水率、导热系数等宏观物理力学性能参数进行了测定,同时借助SEM与Image-Pro plus (IPP)图像处理分析软件表征了材料内部孔隙结构特征。成功制备出了干表观密度214kg/m3、吸水率约8%、抗压强度0.23MPa、导热系数约0.049W/(m K)等综合性能良好的水泥基泡沫绝热材料。完成的主要研究工作如下下:(1)通过对发泡剂起泡能力和泡沫稳定性进行测试与比较,筛选出适合的发泡剂;并在分析比较物理发泡和化学发泡工艺制备水泥基泡沫材料优缺点的基础上,采用了物理化学复合发泡工艺制备轻质水泥基泡沫材料的新方法,最后对不同发泡工艺下的孔结构特征与材料性能进行了对比分析。结果表明:采用物理发泡工艺制备的泡沫材料综合性能最优。(2)加入羟丙基甲基纤维素醚(HPMC)作为稳泡剂以及选择合理水灰比等措施对该材料孔结构进行调控,使材料内部孔结构得到改善,并具有良好的保温性能与力学性能。(3)在已有配合比的基础上通过加入不同掺量的纳米Ti02和石墨粉,利用其具有对红外热反射的功能特性,达到降低材料导热系数的目的。研究表明:在纳米Ti02与石墨粉掺量分别为0.5%, 1.0%时,保温材料导热系数值分别为0.048 lW/(m·K),0.0433W/(m·K),具有优异的热工性能。(4)依据聚合物苯丙乳液与乳胶粉遇水具有成膜的特性,可形成微孔内壁覆膜的封闭孔隙构造,对泡沫保温材料进行憎水改性研究。结果表明:在两者固含量相同时,乳胶粉对材料性能的改善效果要优于苯丙乳液,在大幅降低材料吸水性能的同时还提高了材料的力学性能。(5)利用短切聚丙烯纤维可增强与水泥基体的机械啮合力对材料力学性能进行优化,并通过落球冲击试验表征材料韧性的提高程度。同时对掺入纤维后孔结构形态特征等参数进行了测试与分析,并探讨了微观孔结构对其宏观性能的影响,接着对不同性能之间的相互关系进行了线性拟合分析,发现他们之间具有一定线性相关性。
[Abstract]:With the reform of wall materials and the enforcement of building energy conservation policy in China, the rapid development of building insulation materials has been promoted. Although the traditional organic thermal insulation material has good thermal insulation performance, light weight and low price, it is flammable and burns to produce toxic gas, which makes the contradiction between building energy saving and fire prevention becoming more and more serious. As an ideal substitute, inorganic foam insulation materials are favored for their high safety. However, the inorganic foaming insulation materials used in exterior walls still have some problems, such as large capacity, easy water absorption and large thermal conductivity. Therefore, it is an effective way to solve this contradiction to prepare a kind of inorganic foam adiabatic material with excellent comprehensive properties such as low thermal conductivity, hydrophobicity, light weight and high strength and simple preparation process. In this study, the experimental test and theoretical analysis were used to determine the type and amount of foaming agent, water-cement ratio, foaming stabilizer and other admixtures, respectively, by using single factor and multi-factor control variable method. Finally, the cement-based foam insulation materials were prepared under the suitable foaming technology, and the strength, apparent density, porosity, water absorption of the products were investigated. The macroscopic physical and mechanical properties such as thermal conductivity were measured and the pore structure characteristics of the material were characterized by SEM and Image-Pro plus (IPP) image processing software. Cement-based foam insulation materials with a dry apparent density of 214kg / m3, water absorption of about 8, compressive strength of 0.23 MPa and thermal conductivity of about 0.049W/ (m K) were successfully prepared. The main research work is as follows: (1) by testing and comparing the foaming ability and foam stability of foaming agent, the suitable foaming agent is selected. On the basis of analyzing and comparing the advantages and disadvantages of physical foaming and chemical foaming to prepare cement-based foam materials, a new method of preparing lightweight cement-based foam materials by physical-chemical composite foaming process is presented. Finally, the pore structure and material properties of different foaming processes were compared and analyzed. The results showed that the synthetic properties of the foamed materials prepared by physical foaming process were optimal. (2) adding hydroxypropyl methyl cellulose ether (HPMC) as foam stabilizer and selecting reasonable water-cement ratio to adjust the pore structure of the foams. The internal pore structure of the material is improved, and it has good thermal insulation and mechanical properties. (3) on the basis of the existing mix ratio, the functional properties of infrared heat reflection are obtained by adding nano-sized Ti02 and graphite powder with different amounts. To reduce the thermal conductivity of the material. The results show that the thermal conductivity of the thermal insulation material is 0.048 lW/ (m K) / L 0.0433W / (m K), when the content of nano-scale Ti02 and graphitic powder is 0.5 and 1.0 respectively. (4) according to the characteristics of film formation of polymer styrene-acrylic emulsion and latex powder in water, The sealing pore structure of micropore inner wall covered with film can be formed, and the hydrophobic modification of foam insulation material is studied. The results show that when the solid content of the two is the same, the improvement effect of latex powder on material properties is better than that of styrene-acrylic emulsion. At the same time, the mechanical properties of the materials are greatly reduced. (5) the mechanical properties of the materials can be optimized by the mechanical meshing force between the short cut polypropylene fiber and the cement base body. The toughness of the material was characterized by impact test. At the same time, the parameters such as the morphological characteristics of the rear pore structure of the doped fiber are tested and analyzed, and the influence of the micropore structure on the macroscopic properties is discussed, and then the linear fitting analysis of the relationship between the different properties is carried out. It is found that there is a certain linear correlation between them.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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