Layer Double Hydroxide
In recent years the use of additive or catalyst in the polymer in the industrial field has grown. Layer double hydroxide compound (LDHs) is considered to be positive-charged metal with the ability to substitute with negatively charged anions (Nalwade 2008). The negatively charged anion can insert between the two layers of metal hydroxides by ion-exchange technique. One significant aspect of LDHs that it can protect any anionically charged molecule that get inside the two-layer of hydroxide metal.it comes from the electrostatic force that creates between the two-layer of metal hydroxides which is considered to be cations and the inserted anions.(Nalwade 2008). The combination of LDHs and the exchanged anion give the molecules the satiability to absorb a different kind of severe conditions. Scientist in the industrial field have a major interest in studying (LDHs) in profound ways.
This is an example of significant research in polymer, particularly in LDHs. Evans and Duan (2006) are researchers who have been able to prepare (LDHs) with a colloid mill device. This device helped increased the reaction speed by spinning the flask which contained the LDHs molecules. In the experiment, the velocity of the reaction reaches 3000 rpm. Also, the concentration of the molecules increased on the edge of the Flask as they rotate because of the lift force. This prevents conglomeration of the molecules. As a result, small molecules of LDHs with the same size of crystal at the end of the experiment were found. They called this new method of preparation LDHs the SANS method (separate nucleation and ageing steps). The results of the experiment were compared with the traditional method. In the traditional method, the researcher uses co-precipitation from Aqua solution. The PH of the solution monetarized by adding NaOH to maintain it at 10 which is perfect to precipitate LDHs crystals. Finally, the result of experiments conducted by comparing the finding with a spectrophotometer (Evans and Duan 2006). This research is considered to be significant because it demonstrated for the first time that (LDHs) can be prepared by variety of methods in order to apply it for a specific application. After that many research has been carrying out on this work to prepare LDHs with adjustment for the methodology depending on the needed application.
To illustrate the crucial role of this research in the industrial field, Jiao, Zhao, and Xie (2006) are a researcher from China.They had an interest in preparing Polyethylene with high properties. This polymer is considered to be useful in the horticultural field. It use as plastic cover films for the greenhouse glass. It is considered being a thin material that has high transparency for light as well as low cost for productivity. However, it has many defects which allow the transference of radiated heat and weak heat retention. This made the temperature in the greenhouses very low at night. Jiao, Zhao, and Xie (2006) have been able to improve the thermal ability of Polyethylene films by using (LHDs) that prepared by SANS technique as additive. The results was polyethene films with the ability to maintain a high temperature of the greenhouses especially at night (Jiao et al 2006). This emphasizes the significance of Evans and Duan research (2006) as they carry out their work to apply it in their research.
Moreover, this is another example that emphasizes the importance of various methods to prepare (LDHs) which Evans and Duan (2006) research help conduct for the first time. As Zammorano (2005) and his scientist's partners had carried out on the previous research as they has been able to prepare LDHs by unique method. Their method starts by adding three types of organic acids to the LDHs. These acids replaced the magnesium-aluminium carbonate in LDHs by ion exchange. As a result, it increased the hydrophobic surface of LDHs. They refer to this method as LDHs/epoxy. The results of this research were conducted by comparing the thermogravimetric analyses named called Cone calorimeter tests. Two samples were used LDHs/epoxy and MMT/epoxy, While MMT/epoxy burn in the comparison test, LDHs/epoxy exhibit a distinct self- extinguishing feature. The formidable performance of LDHs/ epoxy makes it efficient application in walled FR products ( Zammorano, et al 2005). Indeed This research demonstrates the importance of methodology to prepare LDHs depends on the needed application. It builds on the idea which Evans and Duan's help illustrate for the first time.
The significant aspect of Evans and Duan (2006) research that it demonstrates for the first time new methodology to prepare LDHs. It opens new concepts and researches to prepare LDHs depending on the needed application. This gathered much interest for researches, especially in the industrial field.
