1. Introduction Nowadays there has been a considerable amount of research interest in recent years in the preparation of various healing agent filled microcapsules. These mi- crocapsules can be used in the development of poly- mer self-healing composites for various applications such as aerospace, automotive, marine and building components etc. Currently, urea and melamine- formaldehyde are the predominant shell wall mate- rials in the preparation of such microcapsules [1–12]. However, the use of both shell wall materials has their own limitations and challenges. Yuan et al. [10] reported that poly(urea-formaldehyde) as a shell ma- terial was hydrophilic in nature, which could result in poor heat-resistance, poor anti-aging properties and higher content of free formaldehyde in the preparation of microcapsules. Though the use of poly(melamine-formaldehyde) resin as a shell mate- rial can increase the mechanical properties of micro- capsules, but it is limited due to its high cost [13]. However, in spite of this the major challenge of these two materials is the use of formaldehyde which is not only a well-known human carcinogen, but also causes indoor air pollution. It has been reported in the literature that with the use of formaldehyde, peo- ple could suffer: irritation in nose, eyes and ear, trou- ble in respiration, vomiting tendency, skin irritation etc. [14–16]. Therefore, there is a need to develop new shell wall material for the preparation of such microcapsules. The use of poly(methyl methacrylate) (PMMA) polymer as a potential shell wall material in mi- croencapsulation process of such microcapsules has been reported in the literature [17–21]. Li et al. [17] 1023 Parametric study for epoxy loaded PMMA microcapsules using Taguchi and ANOVA methods S. Sharma, V. Choudhary * Centre for Polymer Science & Engineering, Indian Institute of Technology, Hauz Khas, 110016 New Delhi, India Received 9 May 2017; accepted in revised form 26 July 2017 Abstract. In this study, we systematically investigated the effect of various process parameters, such as surfactant concentration, core-to-shell ratio taken in the initial feed, temperature and agitation speed on the core content of microcapsules. For this study epoxy loaded poly(methyl methacrylate) microcapsules were prepared by solvent evaporation method. Taguchi orthogonal array with L 25 matrix was implemented to optimize the experimental parameters for such microcapsules. The signal-to-noise ratio (SNR) and analysis of variance (ANOVA) were also performed to determine the optimum parameters and significance of various parameters. Morphological characterization (optical microscopy, scanning electron microscopy and transmission electron microscopy) and particle size analysis (mean particle size and particle size distribution) was done to investigate the effect of various parameters on the prepared microcapsules. SNR analysis identified the optimum levels of various parameters as: sur- factant concentration- 10 wt%, core-to-shell ratio- 3:1, temperature- 40°C and agitation speed- 300 rpm. ANOVA analysis showed that surfactant concentration was the most significant parameter in improving the core content of such microcapsules. The findings of Taguchi method were also verified with contour plots. Maximum core content obtained under optimum condi- tions was 63.53 wt% and such microcapsules can find applications for the development of self-healing polymer composites. Keywords: modelling and simulation, smart polymers, self-healing polymer composites, microcapsules synthesis, epoxy resin eXPRESS Polymer Letters Vol.11, No.12 (2017) 1023–1036 Available online at www.expresspolymlett.com https://doi.org/10.3144/expresspolymlett.2017.96 * Corresponding author, e-mail: veenach@hotmail.com © BME-PT