【作者】 张凌燕；

【导师】 方和平；

【作者基本信息】 武汉理工大学 ， 矿物加工工程， 2003， 硕士

【摘要】 硅灰石是一种新型工业矿物材料，除传统地应用于陶瓷、建材、冶金等行业外，现在被广泛地应用于橡胶、塑料及造纸作为填料。由于无机填料与高分子聚合物的相溶性不好，在聚合物中难以均匀分散，因此要求对硅灰石表面进行改性，使之有机化，提高与聚合物物的相溶性和分散性。 本研究课题以江西和青海硅灰石为试样将硅灰石表面改性与粉碎有机结合起来，采用正交试验的方法确定了以介质搅拌磨、振动磨制备硅灰石针状粉的工艺条件，并考察了影响长径比的主要因素；探讨了冲击式粉碎机转速和给料速度对产物长径比的影响。采用硬脂酸、硅烷对针状硅灰石细粉进行干法、湿法改性，用活性指数，在有机溶剂中的分散性，润湿接触角，吸油值及渗水时间等作为改性效果的预评价指标，考察改性剂用量、改性时间及改性剂种类对硅灰石改性效果的影响，并确定了相应工艺条件。 研究表明，用介质搅拌磨、振动磨和冲击式粉碎机制备硅灰石针状粉长径比L／D=9～11，其中冲击式粉碎机对保证硅灰石的形态特征较其它两种方式更有利；经改性后的硅灰石长径比L／D=5.1～6.3，吸油值湿法44.6～52.4％干法34.7～41.7％，d₅₀湿法9.31～9.56μm，d₅₀干法2.78～3.01μm，活性指数：湿法0.52～0.54，干法0.69～0.88，渗水时间湿法＞390s，干法＞610s；干法改性效果优于湿法。 X射线衍射分析研究表明，硅灰石粉碎过程中，由于机械力化学效应的作用，晶体结构产生了缺陷，发生畸变，颗粒产生非晶化，晶型由三斜T_c型转变为单斜的2M型晶体结构，粉体表面出现高活性点和新表面，使硅灰石表面成为活性表面，促进了改性剂硬脂酸和硅烷在硅灰石表面的吸附包覆或化学键合。 采用红外光谱、扫描电镜对硅灰石改性机理进行研究分析，结果表明，硬脂酸、硅烷结构中的烃基存在于硅灰石表面，—COO^-、—Si—O—等基团与矿物表面存在吸附或包覆作用；烃基的存在使硅灰石表面疏水化，硅灰石与聚合物体系间具有较好的相溶性和分散性。更多还原

【Abstract】 Wollastonite is a material of a new industrial mineral, and is widely applied in rubber, plastics and papermaking as filler, besides traditionally applied in porcelain and ceramics, building materials, metallurgy etc. Because of poor miscibility between abio-filler and high polymers, abio-filler is hardly dispersed in polymer. For this reason, wollastonite is required for surface modification to become organic, and increase miscibility and dispersion in polymer.In this paper, fine grinding of wollastonite from Jangxi and Qinghai is connected with surface modification organically. Processing conditions of preparing acicular powder of wollastonite are confirmed about stirred ball mill and vibrational mill. By means of orthogonal tests, main factors affecting ratio of length to diameter of wollastonite are studied. The effect of rotating speed and feed speed of impacting disintegrator on the ratio of length to diameter of product is studied. By modifying surface of acicular powder of wollastonite with stearic acid and cilane in wet and dry, using activation index, diapersion in organic impregnant, surface contact angle, oil adsorption and penetration time to evaluate effect of modification in advance, the effect of dosage of modification medicament, modification time and type of medicament on the modification effect of wollastonite, and ensure processing conditions are determined.The results of research show that ratio of length to diameter L/D of acicular powder prepared by stirred ball mill, vibrational mill and impacting disintegrator is 9~11. It is more advantage that impacting disintegrator ensures shaped character of crystal than other two. After modification of wollastonite, ratio of length to diameter: L/D=5.1~6.3, oil adsorption: wet 44.6~52.4%, dry 34.7 ~ 41.7%, d50 : wet 9.31 ~9.56 urn, dry2.78~3.01 u m, activation index: wet 0.52~0.54, dry 0.69-0.88, penetration time: Wet > 390s, dry > 610s. Dry modification effect is better than wet effect.X-ray diffraction analysis shows that polymorphic transformation of wollastonite occurs because of the mechano-chemical effect in the process of dry and wet fine-grinding. Some defect and diatortion of wollastonite crystal are presented on the surface of powder. Crystal type turns from triclinic Tc intomonoclinic 2M.There are high activation points on the surface of powder and frash surface of powder, and active surface of wollastonite promoting medicament adsorbing, mantletling and chemical bonding on surface.Through research of principle on surface modification of wollastonite by the IR and the SEM, the results are shown that there are hydrocarbons of stearic acid on surface of wollastonite, and other groups, for example, -COO-, -Si-O-, adsorbing or packing on mineral surface. Because of hydrocarbons, wollastonite surface turns into hydrophobic. This results in better miscibility and dispersion in system of wollastonite and polymer.更多还原