硬脂酸是一種常見的長碳鏈的飽和脂肪酸，同時具有長碳鏈的親油端和羧基的親水端，而納米碳酸鈣表面是親水的，所以把硬脂酸包覆在納米碳酸鈣表面，能大大的改善其親油性，使其填充在橡膠、塑料、油墨、涂料中時，其大的比表面積和高比表面能有利于碳酸鈣顆粒與有機(jī)高聚物分子之間的結(jié)合牢固，能使制品表面光艷和具有優(yōu)異的補(bǔ)強(qiáng)性能。

Stearic acid is a common saturated fatty acid with long carbon chains, which has both the lipophilic end of the long carbon chain and the hydrophilic end of the carboxyl group. However, the surface of nano calcium carbonate is hydrophilic. Therefore, coating stearic acid on the surface of nano calcium carbonate can greatly improve its lipophilicity, making it suitable for filling in rubber, plastics, advanced inks, and coatings, Its large specific surface area and high specific surface energy are conducive to the strong bonding between calcium carbonate particles and organic polymer molecules, which can make the surface of the product shiny and have excellent reinforcement performance.

1、硬脂酸包覆改性納米碳酸鈣的機(jī)理

1. Mechanism of Stearic Acid Coated Modified Nano Calcium Carbonate

采用商業(yè)硬脂酸，在水相條件下包覆沉淀的碳酸鈣，包覆之后的碳酸鈣，硬脂酸的含量為3%~13.5%。采用傅里葉紅外（FTIR）、熱重（TG）和差示掃描量熱（DSC）分析表明在碳酸鈣表面沒有游離的硬脂酸，只存在硬脂酸鈣。發(fā)現(xiàn)形成的硬脂酸鈣在包覆層表面是部分的化學(xué)吸附和部分的物理吸附，并且可以解決在水相條件下碳酸鈣不能表面的全包覆的問題，大的包覆量為3.25%。

Using commercial stearic acid, the precipitated calcium carbonate is coated under aqueous conditions, and the content of stearic acid in the coated calcium carbonate is 3%~13.5%. Fourier transform infrared (FTIR), thermogravimetry (TG) and differential scanning calorimetry (DSC) analysis showed that there was no free stearic acid on the surface of calcium carbonate, but only calcium stearate. It was found that the formed calcium stearate exhibits partial chemical adsorption and partial physical adsorption on the surface of the coating layer, and can solve the problem of calcium carbonate not being fully coated on the surface under aqueous conditions, with a large coating amount of 3.25%.

2、長鏈脂肪酸對碳酸鈣的影響

2. The Effect of Long Chain Fatty Acids on Calcium Carbonate

長鏈脂肪酸的加入不影響碳酸鈣的晶型，但是影響著所生成碳酸鈣粒子的形貌。當(dāng)加入月桂酸時，碳酸鈣粒子的分散性大大提高；當(dāng)加入大量的棕櫚酸和硬脂酸時，形成了微棒狀結(jié)構(gòu)和紡錘狀結(jié)構(gòu)。作者提出，在氫氧化鈣和二氧化碳的碳化反應(yīng)過程中，一方面碳鏈的長度影響了氫氧化鈣懸浮液所形成膠束的形狀，另一方面膠束之間的接觸方式?jīng)Q定了后形成的碳酸鈣的形貌。

The addition of long-chain fatty acids does not affect the crystal form of calcium carbonate, but it affects the morphology of the generated calcium carbonate particles. When lauric acid is added, the dispersity of calcium carbonate particles is greatly improved; When a large amount of palmitic acid and stearic acid is added, a micro rod like structure and a spindle like structure are formed. The author proposes that during the carbonization reaction between calcium hydroxide and carbon dioxide, on the one hand, the length of the carbon chain affects the shape of the micelles formed by the calcium hydroxide suspension, and on the other hand, the contact mode between the micelles determines the morphology of the resulting calcium carbonate.

3、活性納米碳酸鈣的應(yīng)用特點

3. Application characteristics of active nano calcium carbonate

表面改性之后的納米碳酸鈣相比未改性的納米碳酸鈣和商業(yè)碳酸鈣，能夠大大的提高復(fù)合材料的拉伸強(qiáng)度、延伸率和耐磨性能以及阻燃性能。表面改性也能產(chǎn)生強(qiáng)粘合力，這使得聚合物鏈更牢固，聚合物的熱穩(wěn)定提高?；谶@些納米復(fù)合材料的高強(qiáng)度高韌性，可以用于電纜連接器、電氣和照明開關(guān)設(shè)備，在航空航天領(lǐng)域也有重要價值。

After surface modification, nano calcium carbonate can significantly improve the tensile strength, elongation, wear resistance, and flame retardancy of composite materials compared to unmodified nano calcium carbonate and commercial calcium carbonate. Surface modification can also generate strong adhesion, which makes the polymer chain stronger and improves the thermal stability of the polymer. Based on the high strength and toughness of these nanocomposites, they can be used for cable connectors, electrical and lighting switchgear, and also have important value in the aerospace field.

硬脂酸作為一種常見的長鏈脂肪酸，廉價用途廣泛，能夠很好的改性納米碳酸鈣。作為廉價易得的填料，硬脂酸改性之后的活性納米碳酸鈣能夠在眾多有機(jī)體中很好的分散，并且能夠提高有機(jī)體的拉伸強(qiáng)度、延伸率和耐磨性能以及阻燃性能等機(jī)械性能和熱力學(xué)性能，所以選擇硬脂酸對納米碳酸鈣進(jìn)行改性，具有很好的研究和應(yīng)用價值。更多相關(guān)事項就來我們網(wǎng)站http://www.fahao168.com咨詢吧！

Stearic acid, as a common long-chain fatty acid, is cheap and widely used, and can effectively modify nano calcium carbonate. As a cheap and easily available filler, the active nano calcium carbonate modified with stearic acid can be well dispersed in numerous organisms, and can improve the mechanical and thermodynamic properties such as tensile strength, elongation, wear resistance, and flame retardancy of the organism. Therefore, choosing stearic acid to modify nano calcium carbonate has great research and application value. For more related matters, come to our website http://www.fahao168.com Consult!