The aim of this project is to study the influence of the chemical and physical properties of NaSt on the transparency of gel air fresheners and to recommend the optimal parameters of NaSt for use in air fresheners. In this project, only three parameters were studied, namely the effect of free fatty acid (FFA) value and moisture content of NaSt and heating temperature in the production of air freshener. Therefore, a compatible dye and fragrance must be used in correct amounts to maintain the purity of the air freshener.
In other words, NaSt is responsible for promoting the gelling of the air freshener components. Because ethylene glycol is not one of the components in gel air fresheners, this test cannot be used for 'air freshener grade' NaSt. The chemical properties include the free fatty acid (FFA), free alkalinity (FA) and moisture content of the NaSt.
In other words, this project will contribute to the determination of the most suitable grade of NaSt to be used in air fresheners. The main interest of this project lies in the effect of Free Fatty Acid (FFA) value, moisture content (LOD) and heating temperature on gel-based air fresheners' transparency. The color of the air freshener and whether it remains gelled after a period of time will not be of concern in this project.
As mentioned in the introduction, Sodium Stearate (NaSt) is produced by reacting directly with fatty acid (stearic acid) and sodium hydroxide (NaOH).
HUNTER LAB METER (SPECTROPHOTOMETER)
For the detailed method of using the Hunter Lab meter, please refer to the experimental methods in Chapter 3. As with any analytical instrument, the accuracy of the Hunter Lab meter can be compromised due to errors. Errors in measurement can be divided into two categories, namely instrument-related and non-instrumental.
Other sources of stray light include scattering of Ught and unwanted reflections from other optical elements as well as Ught leaks in the instrument. Various analyte-related factors include reflection from air/cell and analyte/cell interfaces, scattering by suspended particles and absorption of light beam by the analyte. The stirring and heating should be stopped as soon as the solution becomes clear.
First, the Hunter Lab Meter is turned on and allowed to warm up for 30 minutes. To cahbrate, a black tile is first placed on the light path and 'Read' button is activated. Next, a gel sample is placed on the light path and the top of the sample is covered with the black tile.
Then the white tile is placed on top of the sample and press 'Read'. Upon addition of NaSt, the D-Limonene becomes cloudy and the fine NaSt powder tends to form small lumps. The solution turns a bright pale yellow with the addition of Ethanol and Deionized (DI) water.
Even after the solution has become clear, lumps of NaSt remain in the solution (this is observed for NaSt 200). At temperatures between 90°C-110°C, the D-Limonene-NaSt mixture is a cloudy yellow color and has a sticky texture.
FREE FATTY ACID (FFA) AND MOISTURE CONTENTS (LOD) OF
The first round of air freshener production and testing was done on the NaSt200 and NaSt CP samples mentioned above. To ensure a homogeneous air freshener solution, the clumps must be broken by hand with a spatula. Therefore, NaSt (gelling agent) can be said to absorb the DI water and possibly nonylphenol and ethanol to increase the viscosity of the air freshener solution and thus form a gel.
However, looking at the measurements obtained, it can be seen that the transparency of the gel generally decreases with increasing FFA value. From Figure 8, it was observed that FFA values of NaSt have an effect on gel transparency. From Table 3 and Figure 11, it can be observed that the transparency of the gel will generally decrease with increasing FFA values.
To determine the effect of moisture content on air freshener gel transparency, NaSt samples from pellet no. 18 dried in the oven for different periods of time to obtain samples with different moisture contents. From the above results and observations, it can be concluded that the moisture content of NaSt affects not only the transparency of the gel, but also its strength and. It can be seen from Table 5 and Figure 13 that the transparency of the air freshener decreases slightly with increasing temperature.
There are several factors that a gel-based air freshener manufacturer must consider when producing air fresheners. The type and amount of fragrance used in the air freshener is one of the main causes of cloudiness. With this project, the student succeeded in determining the effects of FFA value, moisture content and heating temperature on the transparency of gel-based air fresheners.
It has also been observed that the transparency of the gel-based air freshener decreases with decreasing NaSt moisture content. Therefore, it can be concluded that the effect of NaSt moisture content on the transparency of the air freshener is negligible. Therefore, it can be said that the air freshener solution should not be prepared at temperatures above 90°C.
Another reason why the air freshener should not be prepared beyond this temperature is that its viscosity will decrease, thus leading to a longer gel period. In general, it can be summarized that NaSt 200 and NaSt CP (ground to 100 mesh) produced at StabUchem (M) Sdn.
