Modelling and Optimal Viscometry Formulation Evaluation of a Modified Green Based Self-Healing Automotive Paint

This research successfully converted periwinkle shells, an agrowaste of regenerative resource, to an additive for the formulation of a self-healing car paint. The periwinkle shell was deproteinized, demineralised and deacetylyzed to produce chitosan. The parent chitosan sample in a series of reactions was modified by graft copolymerization with maleic anhydride and methyl methacrylate to yield a chitosan derivate (chitosan-g-maleic anhydride-g-(methyl methacrylate) copolymer (modified chitosan). A 24 full factorial central composite rotatable experimental design and a three-layered (4:n:1) feed-forward architecture of artificial neural network trained by the Levenberg-Marquardt backpropagation algorithm was employed to model and predict the process variables. The physicochemical properties of the paint formulations were studied using standard methods. Fourier Transform Infrared was used to identify the functional groups of the samples under investigation. Grafting efficiency (GE %) of 75.3% and grafting yield (G %) of 76.25% indicates effective graft copolymerization of methyl methacrylate on to the maleilated chitosan. The functional groups revealed by the FTIR spectra confirmed the graft copolymerization of maleilated chitosan with methyl methacrylate to yield a chitosan derivate (chitosan-g-maleic anhydride-g-(methyl methacrylate) copolymer and also identified the presence of the modified chitosan in the self healing paint. The drying time, adhesion and chemical resistance properties measured were within acceptable limits. ANOVA results show that quadratic equation best describes the viscometry behaviour of the paint formulation. The binder and solvent showed significant effect on the response. The AAD (%) and coefficient of determination values obtained for RSM and ANN show that the two techniques predicted to a great extent the viscometry behaviour of the system, however, ANN model marginally outperformed the RSM model. An optimal response of 99.85mPa.s was recorded at 70.24g binder, 79.99g solvent, 15.72g pigment and 3g additives.