本文關(guān)鍵詞： MOS前驅(qū)物 水熱法 單分散納米氫氧化鎂晶須 形成機(jī)制　出處：《沈陽(yáng)理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：納米氫氧化鎂晶須是一種新型綠色功能材料,具有表面能低、機(jī)械性能優(yōu)良、彈性模量較高等特性。用作復(fù)合材料添加劑不僅可以提高材料的力學(xué)性能,還能有效提高材料的阻燃、抑煙性能。目前,對(duì)于納米氫氧化鎂晶須的制備研究多處于實(shí)驗(yàn)室階段,對(duì)于其形成機(jī)制的研究尚未見(jiàn)文獻(xiàn)報(bào)道。本課題主要采用水熱合成法來(lái)制備單分散納米級(jí)氫氧化鎂晶須,并對(duì)其形成機(jī)制進(jìn)行探討。本文以菱鎂礦制備出的亞微米級(jí)堿式硫酸鎂晶須(Mg SO4·5Mg(OH)2·3H2O簡(jiǎn)稱MOS)為原料,Na OH為沉淀劑,采用水熱法制備單分散納米氫氧化鎂晶須。采用單因素實(shí)驗(yàn)法,探討MOS初始料漿濃度、Na OH/MOS摩爾比、水熱反應(yīng)溫度、反應(yīng)時(shí)間、攪拌轉(zhuǎn)速、助劑種類及添加量、MOS性能等因素對(duì)制備產(chǎn)物性能的影響。利用SEM、XRD、EDS、FT-IR、TG-DSC等先進(jìn)的測(cè)試手段對(duì)制備產(chǎn)物的微觀形貌、物相組成、元素含量、表面基團(tuán)、熱穩(wěn)定性進(jìn)行了測(cè)試分析;應(yīng)用統(tǒng)計(jì)學(xué)規(guī)律,以晶須總數(shù)≥100為統(tǒng)計(jì)總數(shù),單根晶須占晶須總數(shù)的百分比稱為單根晶須含量,以此來(lái)表征納米氫氧化鎂晶須的分散性。通過(guò)對(duì)各影響因素的不斷優(yōu)化設(shè)計(jì),得出最佳制備參數(shù)為:MOS前驅(qū)物平均直徑≤200nm、MOS前驅(qū)物平均長(zhǎng)徑比100、MOS初始料漿濃度0.03mol/kg、反應(yīng)溫度180℃、反應(yīng)時(shí)間4h、Na OH/MOS摩爾比4.5:1、攪拌轉(zhuǎn)速100r/min、添加劑種類為硬脂酸鈉、硬脂酸鈉/MOS質(zhì)量比2%。最佳制備條件下產(chǎn)物平均直徑85nm,平均長(zhǎng)度14μm,平均長(zhǎng)徑比100,晶須直徑D在80~95nm范圍占統(tǒng)計(jì)晶須總數(shù)的57%,晶須長(zhǎng)度L在10~15μm范圍占統(tǒng)計(jì)晶須總數(shù)的66%,長(zhǎng)徑比L/D在100~180范圍占統(tǒng)計(jì)晶須總數(shù)的70%;合成產(chǎn)物為納米Mg(OH)2晶須且純度較高;晶須的熱分解溫度范圍為318~490℃,在380~420℃之間熱分解速率最快。在最佳實(shí)驗(yàn)條件下,通過(guò)過(guò)程取樣,取出不同時(shí)刻的反應(yīng)液,測(cè)得溶液中OH-和SO42-的濃度,根據(jù)結(jié)晶動(dòng)力學(xué)原理,利用MATLAB軟件和Runge-Kutta數(shù)值算實(shí)驗(yàn)數(shù)據(jù)進(jìn)行處理,得出結(jié)晶動(dòng)力學(xué)方程:以O(shè)H-濃度為基準(zhǔn):22300.179()()dcc c c c dt￥- = - -以SO42-濃度為基準(zhǔn):22300.154()()dcc c c c dt￥=--最終確定晶須形成的動(dòng)力學(xué)模型為MA-2,結(jié)晶過(guò)程受多核表面反應(yīng)控制。根據(jù)氫氧化鎂晶須的結(jié)晶動(dòng)力學(xué)模型,結(jié)合實(shí)驗(yàn)結(jié)果與相關(guān)理論進(jìn)行綜合分析并得出結(jié)論:本實(shí)驗(yàn)條件下納米氫氧化鎂晶須形成過(guò)程既包括以MOS為模板的模板機(jī)制,又包含液固機(jī)制下的螺旋位錯(cuò)生長(zhǎng)方式。
[Abstract]:Nanocrystalline magnesium hydroxide whisker is a new green functional material with low surface energy, excellent mechanical properties and high elastic modulus. At present, the preparation of nano-magnesium hydroxide whiskers is in the laboratory stage. The mechanism of its formation has not been reported in literature. In this paper, monodisperse nano-sized magnesium hydroxide whiskers were prepared by hydrothermal synthesis. The formation mechanism was discussed. In this paper, the monodisperse nano-magnesium hydroxide whiskers were prepared by hydrothermal method, using mg SO4 路5MgOH2 路3H2O as precipitant and magnesium sulfate whisker prepared from magnesite as raw material. The initial slurry concentration of MOS, Na OH/MOS molar ratio, hydrothermal reaction temperature, reaction time and stirring speed were studied. The influence of the kinds of additives and the addition amount of MOS on the properties of the prepared products was studied. The microstructure, phase composition, elemental content, surface group and thermal stability of the prepared products were tested and analyzed by means of advanced testing methods, such as SEMXRDX EDST-IRT TG-DSC. According to the statistical law, taking the total number of whiskers 鈮，

本文編號(hào)：1555895