Influence of SDS on Composite Properties from ANOVA

ANOVA is a useful and practical statistical tool in developing a model from scratch. ANOVA as a design of experiment tool has proven to aid in optimization studies (Sudharsan and Ng 2000 Meador et al. 2009), parametric and behavioral studies (Nguyen et al. 2009) and development of empirical models (Montgomery 2013). ANOVA uses different types of experimental design techniques and statisticians can deploy whichever strategy that is deemed adequate to their research. 

In the experiments and studies carried out, a full quadratic empirical model including all main effects, second-order effects, and two- and three-way interactions were accounted via multiple linear regression analysis to determine the properties. Terms that were not significant in the model ( 95 % confidence) were eliminated one at a time. The general empirical model for all the properties evaluated is given in Eq. (5.4). ANOVA present simple empirical formulation of the properties to be 

ANOVA showed that strain rate does not have any effect on any of the mechanical properties, thus the %Srate data are normalized at 1.0/min by averaging the response. However, it is noted that %CS is a significant term for strain recovery but not for the others. Therefore, the empirical analysis of strain recovery involves three variables, whereas the others involve only the mixing ratio of the constituents. The coefficient terms are solved using the regression analysis in MATLAB by 

However, with the addition of SDS, strain recovery is almost 80-90 % at low mass fraction of gelatin ( 14 %). The upper bound lines for both empirical and experiment data are closely packed and there is little difference between them. Thus, the empirical model trend-line correlates well with the experimental data providing reasonable estimation of strain recovery for gelatin content of 2—50 % and SDS content between 0 and 0.66 %. 

The addition of SDS into the solution of gelatin increases the foaming capacity significantly as seen in Fig. 5.9b. As a result, the volume of the foamed solution increases thus reducing the density of the composite when compared with those without SDS additive. The density factor (D,) is expressed as shown in Eq. (5.5). 

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