Study on car shampoo formulation using D-optimal statistical design

Krishnaiah et al. International Journal of Industrial Chemistry 2012, 3:31 http://www.industchem.com/content/3/1/31 RESEARCH Open Access Study on car shampoo formulation using D-optimal statistical design Duduku Krishnaiah*, Rosalam Sarbatly, SM Anisuzzaman and Enddy Madais Abstract Background: In this investigation car shampoo formulation was studied. The quality of car shampoo is directly linked to the basic material used in the formulation. By varying the ratio of ingredients such as sodium metasilicate (SMS), sodium lauryl ether sulphate (SLES), coco dimethyl betaine (betaine), coconut fatty acid diethanolamide (CDE) and linear alkyl benzene sulphonate (LABS), the final product characteristics were determined. A common problem in pre-formulation is the optimization of the mixture composition which is aimed to obtain a product with the required characteristics. Results: In this work, various composition surfactants were used to prepare the car shampoo formulations. The D-optimal mixture design was performed to obtain the optimum formulation. Twenty-five combination components were selected according to the D-optimal criterion. Physical properties of the car shampoo such as pH, power of removal and foaming ability were studied. Contour graphics were formed to assess the change in the response surface in order to understand the effect of the mixture composition on car shampoo characteristics. Conclusion: The statistical study shows that the fitted model was adequate to describe the viscosity response. The optimum composition formulation was SMS 1.48%, SLES 3.52%, betaine 4.0%, CDE 4.5% and LABS 1.5%. Keywords: Surfactant, Car shampoo formulation, D-optimal mixture design, Foaming Background The production of new cars is increasing year by year. The detergent demand for car washing is also increasing in parallel with production of cars. Car shampoo is produced from the combination of surfactant, fragrance, stabiliser and other materials [1]. The good formulation consists at least of five components. Surfactant is the base material of the car shampoo formulation. It is the chemical species that is active and has a preference for a surface or interface which is the boundary between two phases. When the surfactant is used as emulsifier, it decreases the energy differences between the two phases to allow a relative stable mixture of oil and water. Generally, surfactant can be divided into four main groups: anionic, nonionic, cationic and amphoteric based on the chemical group [2-4]. The problem faced in the car shampoo formulation development is to achieve the optimum performance with good appearance and stability. In the formulation * Correspondence: Chemical Engineering Programme, School of Engineering and Information Technology, Universiti Malaysia Sabah, Kota Kinabalu, Sabah 88400, Malaysia work, statistical experimental design is commonly used to obtain a product with the required characteristics. The primary goal of designing an experiment statistically is to obtain valid results at minimum of effort, time and resources [5]. There were several experimental design techniques used for formulation work such as factorial design and mixture design. However, it should be noted that factorial design cannot be used to study in such mixtures since the variables are not independent. The sum of all fractions of the components used must be equal to 1 [6-10]. The mixture design represents an efficient approach for solving such optimisation problem. It was found to be an effective tool to select the best liquid detergent formulation [11]. This research was based on the five main surfactants, namely, sodium metasilicate (SMS), sodium lauryl ether sulphate (SLES), coco dimethyl betaine (betaine), coconut fatty acid diethanolamide (CDE) and linear alkyl benzene sulphonate (LABS). These surfactants are widely used in detergent industry as these are biodegradable. The formulations were based on the composition designed by D-optimal mixture method. Physical properties of the car © 2012 Krishnaiah et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Krishnaiah et al. International Journal of Industrial Chemistry 2012, 3:31 http://www.industchem.com/content/3/1/31 shampoo such as pH, foaming ability and power of removal were studied. The responses of these components were analysed and optimised. Contour graphics were formed to assess the change in the response surface in order to understand the effect of the mixture composition on car shampoo characteristics. Methods Chemicals All the chemicals (analaytical grade), sodium metasilicate (SMS), sodium lauryl ether sulphate (SLES), coco dimethyl betaine (betaine), coconut fatty acid diethanolamide (CDE) and linear alkyl benzene sulphonate (LABS) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Detergency evaluation: pH test The pH test is the one of the detergency evaluation parameters in car shampoo formulation. The pH metre was calibrated before the pH test was performed. Five readings were taken to get the average pH data for each formulation. Foaming ability test The foaming was measured based on the height of the foam in the used container. The mechanical stirrer has been used to produce the foam. The volume of the foam was calculated by using Equation 1. Foam volume ¼ π r 2 H ð1Þ where r is the radius of beaker and H is the height of foam in millimetres. Page 2 of 8 Power of removal test The power of removal of car shampoo formulation was estimated by using weighed soil before and after washing. The soil used in this research is the motor oil waste (degraded motor oil). The substrate used in the laboratory test is steel plate. One layer of soil (motor oil) was spread in the entire surface of the plate before the test was performed (initial weight). The mechanical stirrer assisted the removal of the oil. After washing, the plate was dried in the oven and the final weight was measured. The formula used in this test is shown in Equation 2 [12,13]. W ¼ W F  Wi ; where W is the soil removed, WF is the final weight, and Wi is the initial weight. Results and discussion Relationship between composition and pH Tables 1 and 2 represent the results of mean, linear, quadratic, special cubic and full cubic models of the data obtained. The computations were performed using Design Expert computer programme (version 6.09, Stat-Ease Inc., Minneapolis, MN, USA). The sequential F-tests in these tables indicate that the contribution of the mean, linear and special cubic model is significant. However, the terms in special cubic and cubic model are aliased and were ignored. Furthermore, the quadratic model is chosen because it has a larger adjusted R value compared to the ot (...truncated)