本文關(guān)鍵詞： 納米CaCO_3 表面改性 氨基酸 活化度 耐酸性 CaCO_3/SiO_2復(fù)合物　出處：《南昌大學》2015年碩士論文　論文類型：學位論文

【摘要】：納米碳酸鈣(CaCO3)是一種應(yīng)用廣泛的無機填料,但由于粒度小、表面能高、親水性強、耐酸性差等缺陷,在應(yīng)用過程中必須對其進行表面改性。本實驗選取氨基酸和二氧化硅對納米CaCO3進行改性研究,制備改性納米CaCO3,對反應(yīng)過程中的條件進行了探索和優(yōu)化。通過在納米CaCO3漿液中加入氨基酸,在納米CaCO3表面引入羧基、氨基等活性基團實現(xiàn)表面改性,并用FTIR. XRD和TGA等手段對改性機理進行研究。結(jié)果表明,L-賴氨酸、谷氨酸是以化學鍵合的形式接枝到納米CaCO3表面；谷氨酸改性優(yōu)于L-賴氨酸；改性前后沒有出現(xiàn)新的衍射峰；氨基酸改性后納米CaCO3的衍射峰強度明顯降低,且谷氨酸改性樣的衍射峰強度低于L-賴氨酸改性樣強度。碳化法制得納米CaCO3,CaCO3平均粒徑55nm左右,方解石結(jié)構(gòu),晶型結(jié)構(gòu)較好,結(jié)晶度較高。L-賴氨酸接枝納米CaCO3最佳工藝條件為：超聲分散1h,水為改性溶劑,CaCO3料漿濃度8～10wt%,L-賴氨酸用量m(L-賴氨酸)：m(納米CaCO3)=10wt%,改性溫度70℃,改性時間70min,攪拌速率80Orad/min。在此優(yōu)化工藝條件下,改性納米CaCO3的活化度46.9%,吸油值42.37g/100g。谷氨酸改性納米CaCO3最佳工藝條件為：CaCO3料漿濃度10wt%,m(谷氨酸)/m(CaCO3)=10wt%,改性溫度90℃,改性時間100min。優(yōu)化條件下,改性納米CaCO3的活化度86.07%,吸油值23.64g/100g。以氨水、納米CaCO3和磷肥工業(yè)副產(chǎn)物氟硅酸為原料,制備了CaCO3/SiO2復(fù)合物。實驗確定了SiO2包覆CaCO3的適宜條件：反應(yīng)溫度60℃,配料比m(SiO2)/m(CaCO3)=8wt%,反應(yīng)終點pH值9.0,陳化時間8h以上,優(yōu)化條件下,浸泡CaCO3/SiO2復(fù)合物24h的緩沖溶液c(Ca2+)=0.014mol/L,耐酸性能好,包覆后納米CaCO3的耐酸性能明顯提高。對適宜條件下的包覆產(chǎn)品進行FTIR、XRD和粒度分析,結(jié)果表明：SiO2與CaCO3發(fā)生了化學鍵合作用,SiO2以無定型態(tài)包覆于納米CaCO3表面,包覆后納米CaCO3粒徑變小,平均粒徑44.67nm。
[Abstract]:Nano calcium carbonate (CaCO3) is a widely used inorganic filler, but due to its small particle size, high surface energy, strong hydrophilicity, poor acid resistance, etc. In this experiment, amino acid and silica were selected to modify the surface of CaCO3. The modified nano-CaCO _ 3 was prepared, and the reaction conditions were explored and optimized. The surface modification was realized by adding amino acids to the nano-CaCO _ 3 slurry, introducing carboxyl groups, amino groups and other active groups on the surface of nano-CaCO _ 3. The modification mechanism was studied by FTIR. XRD and TGA. The results showed that L- lysine and glutamic acid were grafted to the surface of nano-#en2# in the form of chemical bonding, the modification of glutamate was superior to that of L- lysine, and there were no new diffraction peaks before and after modification. The diffraction peak intensity of CaCO3 modified by amino acid was obviously decreased, and the diffraction peak intensity of glutamic acid modified sample was lower than that of L- lysine modified sample. The average diameter of nano-CaCO3 / CaCO3 was about 55 nm, and the calcite structure and crystal structure were better than that of L- Lysine modified sample. The optimum technological conditions of high crystallinity. L- lysine grafted nanocrystalline CaCO3 were as follows: ultrasonic dispersion for 1 hour, water as the modified solvent for 8 ~ 10 wts, L- L- lysine dosage ML-L- 1: M (nano-CaCO3 + 10wt), modification temperature 70 鈩，

本文編號：1516928