Nakanishi Yurie, Cheng Bohan, Richardson Joseph J, Ejima Hirotaka
Department of Materials Engineering, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
School of Engineering, RMIT University Melbourne VIC 3000 Australia.
RSC Adv. 2023 Oct 18;13(43):30539-30547. doi: 10.1039/d3ra04791a. eCollection 2023 Oct 11.
Calcium carbonate (CaCO) is a naturally occurring mineral that occurs in biology and is used industrially. Due to its benign nature, CaCO microparticles have found use in the food and medical fields, where the specific size of the microparticles determine their functionality and potential applications. We demonstrate that phenolic polymers with different numbers of hydroxy groups can be used to control the diameter of CaCO microparticles in a range of 2-9 μm, and obtained particles were relatively uniform. The largest particles (∼9 μm in diameter) were obtained using poly(2,3,4,5-tetrahydroxystyrene) (P4HS), which showed the highest water solubility among the tested phenolic polymers. The polymer concentration and stirring speed influenced the size of microparticles, where the size of the obtained particles became smaller as the concentrations of phenolic polymers increased and as the stirring speed increased, both likely due to promoting the formation of a large number of individual crystal seeds by shielding seed-seed fusion and increasing the chances for precursor contact, respectively. The preparation time and temperature had a great influence on the morphology of the CaCO particles, where vaterite transforms into calcite over time. Specifically, aragonite crystals were observed at preparation temperature of 80 °C and vaterite particles with rough surfaces were obtained at 40 °C. Molecular weight and scale of reaction were also factors which affect the size and morphologies of CaCO particles. This research represents a facile method for producing relatively monodisperse CaCO microparticles with diameters that have previously proven difficult to access.
碳酸钙（CaCO₃）是一种天然存在的矿物质，存在于生物体内并在工业中得到应用。由于其性质温和，碳酸钙微粒已在食品和医疗领域得到应用，其中微粒的特定尺寸决定了它们的功能和潜在应用。我们证明，具有不同羟基数目的酚类聚合物可用于将碳酸钙微粒的直径控制在2-9μm范围内，并且所获得的颗粒相对均匀。使用聚（2,3,4,5-四羟基苯乙烯）（P4HS）获得了最大的颗粒（直径约9μm），其在测试的酚类聚合物中显示出最高的水溶性。聚合物浓度和搅拌速度影响微粒的尺寸，随着酚类聚合物浓度的增加和搅拌速度的增加，所获得颗粒的尺寸变小，这可能分别是由于通过屏蔽晶种-晶种融合促进大量单个晶种的形成以及增加前驱体接触的机会。制备时间和温度对碳酸钙颗粒的形态有很大影响，其中球霰石会随着时间转化为方解石。具体而言，在80°C的制备温度下观察到文石晶体，在40°C下获得了表面粗糙的球霰石颗粒。分子量和反应规模也是影响碳酸钙颗粒尺寸和形态的因素。这项研究代表了一种简便的方法，用于生产直径相对单分散的碳酸钙微粒，而这些直径以前被证明难以获得。
