دانلود رایگان مقاله لاتین مونت موریلونیت با نمک آمونیوم از سایت الزویر
عنوان فارسی مقاله:
مطالعه مقایسه ای مسیرهای مختلف ایجاد تغییر در مونت موریلونیت با نمکهای آمونیوم و فسفونیم
عنوان انگلیسی مقاله:
A comparative study of different routes for the modification of montmorillonite with ammonium and phosphonium salts
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Nowadays, there is a large field of study focusing clays as nanofillers for polymeric materials, especially bentonite which the main clay mineral is montmorillonite (Breakwell et al., 1995; Lee and Lee, 2004; Bergaya et al., 2006; Paiva et al., 2008; Khalaf and Hegazy, 2012; Liu et al., 2014). Montmorillonite is a 2:1 layered aluminosilicate of smectite group, electrically charged with negative charges that are compensated by inorganic cations, such as Na+ and Ca2+. The great interest in the study and use of these materials are due to their excellent properties, such as low particle size, high specific surface area, aspect ratio, cation exchange capacity (CEC) and absorption and adsorption capacity, as well as high abundance and low cost (Utracki, 2004; Bergaya et al., 2006). However, there are limitations to the use of these minerals in their raw form due to the large amount of impurities and surface incompatibility with the polymer, once it has hydrophilic characteristics. Therefore, it is necessary a prior purification of these materials and its modification to make them organophilic/hydrophobic (Utracki, 2004; Bergaya et al., 2006; Paiva et al., 2008; Zanini, 2008; Alves, 2012; Alves et al., 2016). Organo-montmorillonite (O-Mt) has been extensively used in various applications, and more recently as reinforcement in clay polymer nanocomposites (CPN). The need to obtain superficially modified clays aiming at thermal stability and compatibility with polymers has resulted in intensification in the search and studies of new substances in the recent years. Cationic surfactants based on quaternary ammonium salts have been the organic compounds mostly used to organoclays production (Breakwell et al., 1995; Paiva et al., 2008; Thompson et al., 2008; Sarkar et al., 2011; Khalaf and Hegazy, 2012; Takahashi et al., 2013;). However, these kind of compounds are known to have poor thermal stability and in some cases toxicity (Paiva et al., 2008; Sarkar et al., 2012). Others organic compounds with higher thermal stability and lower toxicity have been used to clay minerals functionalization, mostly in laboratory scale, such as ionic liquids based on phosphonium salts (Ha and Xanthos, 2009; Livi et al., 2010, 2011a, 2011b) and imidazolium salts (Ha and Xanthos, 2009; Livi et al., 2010, 2011a, 2011b; Takahashi et al., 2013), nonionic surfactants (Guégan, 2010, 2013; Li et al., 2012; Guégan et al., 2014; Silva et al., 2014) and anionic surfactants (Du et al., 2010). The production of organoclays can be made by various routes, being the cation exchange the most used. This consists in replacing inorganicNowadays, there is a large field of study focusing clays as nanofillers for polymeric materials, especially bentonite which the main clay mineral is montmorillonite (Breakwell et al., 1995; Lee and Lee, 2004; Bergaya et al., 2006; Paiva et al., 2008; Khalaf and Hegazy, 2012; Liu et al., 2014). Montmorillonite is a 2:1 layered aluminosilicate of smectite group, electrically charged with negative charges that are compensated by inorganic cations, such as Na+ and Ca2+. The great interest in the study and use of these materials are due to their excellent properties, such as low particle size, high specific surface area, aspect ratio, cation exchange capacity (CEC) and absorption and adsorption capacity, as well as high abundance and low cost (Utracki, 2004; Bergaya et al., 2006). However, there are limitations to the use of these minerals in their raw form due to the large amount of impurities and surface incompatibility with the polymer, once it has hydrophilic characteristics. Therefore, it is necessary a prior purification of these materials and its modification to make them organophilic/hydrophobic (Utracki, 2004; Bergaya et al., 2006; Paiva et al., 2008; Zanini, 2008; Alves, 2012; Alves et al., 2016). Organo-montmorillonite (O-Mt) has been extensively used in various applications, and more recently as reinforcement in clay polymer nanocomposites (CPN). The need to obtain superficially modified clays aiming at thermal stability and compatibility with polymers has resulted in intensification in the search and studies of new substances in the recent years. Cationic surfactants based on quaternary ammonium salts have been the organic compounds mostly used to organoclays production (Breakwell et al., 1995; Paiva et al., 2008; Thompson et al., 2008; Sarkar et al., 2011; Khalaf and Hegazy, 2012; Takahashi et al., 2013;). However, these kind of compounds are known to have poor thermal stability and in some cases toxicity (Paiva et al., 2008; Sarkar et al., 2012). Others organic compounds with higher thermal stability and lower toxicity have been used to clay minerals functionalization, mostly in laboratory scale, such as ionic liquids based on phosphonium salts (Ha and Xanthos, 2009; Livi et al., 2010, 2011a, 2011b) and imidazolium salts (Ha and Xanthos, 2009; Livi et al., 2010, 2011a, 2011b; Takahashi et al., 2013), nonionic surfactants (Guégan, 2010, 2013; Li et al., 2012; Guégan et al., 2014; Silva et al., 2014) and anionic surfactants (Du et al., 2010). The production of organoclays can be made by various routes, being the cation exchange the most used. This consists in replacing inorganiccations present in the interlayer spaces of clay minerals by organic cations of long chains. The exchange reaction is preferably made with sodium-clay minerals than calcium-clay minerals due to monovalent cations of sodium allow greater water interleaving in the interlayer spaces (higher hydration), further increasing the space between the layers, which facilitates the entry of organic cations (Bergaya et al., 2006; Utracki, 2004; Paiva et al., 2008). The preparation of this material by traditional routes involves environmental impacts due to the use of large amounts of water. Then, the need to seek and study new cationic intercalation compounds and new processes that minimize the environmental aspects in the area of cationic modification of clay minerals, aiming its efficiency dispersion in polymer matrices, comes every day to be more intensified. Recent studies have also been considering the development of new routes of cation exchange, targeting the reaction yield with attention to environmental impacts and costs associated with these processes. The methods of clay minerals intercalation with organic compounds are fast, efficient and practical, as the organophilization in aqueous dispersion. The methodology is quite simple. The major disadvantage of this method is the use of large amounts of solvents, manly water (to reaction and wash steps) generating high operating costs and environmental impact (Utracki, 2004; Bergaya et al., 2006; Paiva et al., 2008; Paiva and Morales, 2012). The use of alternative systems such as supercritical CO2 (Naveau et al., 2009; Livi et al., 2011a), solid/solid (Ogawa et al., 1989; Zhuang et al., 2015), and “semi-solid” state (Paiva and Morales, 2012), promise to be less impactful to the environment, since they do not consume or generate waste solvents. There is still no clear-cut processing condition such as reaction time, temperature, agitation, pressure, amount of reagent and solvent to conduct an effective and reaction using these methods as we can see in the literature different conditions been applied (Breakwell et al., 1995; Lee and Lee, 2004; Paiva et al., 2008; Avalos et al., 2009; Ha and Xanthos, 2009; Naveau et al., 2009; Dweck et al., 2011; Livi et al., 2011a; Paiva and Morales, 2012; Zhuang et al., 2015). There are also aspects of solubility of organic substances in relation to the dispersion media, and studies in this area are still scarce. Currently, purified and organophilic clays do not have large-scale production in Brazil and the world market for this product has a limited number of manufacturers and high costs. In this work the modification of bentonite extracted from a mine located in Vitória da Conquista, Bahia-Brazil with different surfactants was studied. Thus, this work yet proposes a comparative study of different routes of modification of clay minerals in aqueous, semi-solid or supercritical CO2 medium, aiming efficiency and low environmental impact. For this, design of experiments and statistical studies were made with the objective to evaluate some key parameters and their influence in the process and in the final modified clay characteristics.
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کلمات کلیدی:
Modification and characterization of bentonite with quaternary ... journals.sagepub.com/doi/abs/10.1177/0892705713486123 by T Seyidoglu - 2015 - Cited by 4 - Related articles Modification and characterization of bentonite with quaternary ammonium and phosphonium salts and its use in polypropylene nanocomposites. Show less ... Swelling behaviour of montmorillonite cation exchanged for omega-amino acids by ... A comparative study of different routes for the modification of ... https://www.researchgate.net/.../305660039_A_comparative_study_of_different_routes_... Nov 11, 2016 - A comparative study of different routes for the modification of montmorillonite with ammonium and phosphonium salts. Article in Applied Clay ... Thermally stable phosphonium-montmorillonite organoclays https://www.researchgate.net/.../222278499_Thermally_stable_phosphonium-montmoril... Thermally stable phosphonium-montmorillonite organoclays on ... Sodium montmorillonite (MMT) was modified with several organic phosphonium salts. Organoclays ... exhibit higher thermal stability than conventional ammonium organoclays. Phosphonium salt intercalated montmorillonites - ResearchGate https://www.researchgate.net/.../225030808_Phosphonium_salt_intercalated_montmorill... This phosphonium salt modified montmorillonite is thermally more stable and easier ... Ion exchange with surfactant cations such as quaternary ammonium salts ... Interfacial Modification of Magnetic Montmorillonite (MMT) Using ... pubs.acs.org/doi/pdf/10.1021/jp505225z by L Xu - 2014 - Cited by 8 - Related articles Aug 11, 2014 - clays.5−8 For these reasons, interfacial modifications of clay materials are ... quaternary ammonium or phosphonium salts.9−11 Unfortu- nately ... [PDF]Investigation of adsorption behavior of phosphonium salts onto Na ... www.minproc.pwr.wroc.pl/journal/pdf/ppmp50-2.417-432.pdf by K CINKU - 2014 - Cited by 2 - Related articles organic compounds, like ammonium and phosphonium salts, are very important ... Keywords: Na-montmorillonite, phosphonium salts, adsorption ... nanoclays and organoclays (organically modified layered silicates) has been a turning. Synthesis of quaternary phosphonium salts with ester functional group ... link.springer.com/article/10.1007/s11595-013-0772-8 by H Wang - 2013 - Cited by 3 - Related articles Jul 13, 2013 - Both of quaternary ammonium and quaternary phosphonium salts of ... Thermal stability of BHETPP-modified MMT is much better than that of ... quaternary phosphoniumbis-hydroxyethyl terephthalatemontmorillonitebasal ...
