Contents lists available at ScienceDirect International Journal of Adhesion and Adhesives journal homepage: www.elsevier.com/locate/ijadhadh Design of experiments for optimization a biodegrable adhesive based on ramon starch (Brosimum alicastrum Sw.) A. Ortiz-Fernández a , F.A. Carrillo-Sánchez a , L.H. May-Hernández a , R.J. Estrada-León a , H.J. Carrillo-Escalante b , F. Hernández-Sánchez b , A. Valadez-Gonzalez b, ⁎ a Instituto Tecnológico Superior de Calkiní, en el Estado de Campeche, Av. Ah-Canul S/N. Carretera Federal, CP24900 Calkiní, Campeche, México b Centro de Investigación Científica de Yucatán, A.C. (CICY), Unidad de Materiales, Calle 43 # 130, Col. Chuburná de Hidalgo, CP97200 Mérida, Yucatán, México ARTICLE INFO Keywords: Adhesive Adherent Response surface methodology Central composite design Peel strength Shear strength ABSTRACT In this work, a Central Composite Design (CCD) and Response Surface Methodology (RSM) were used to study the effect of starch content, hydrolyzing agent (NaOH) content, temperature and cooking period on peel strength and shear strength of biodegradable adhesives based on Ramon (Brosimum alicastrum Sw.) and Corn (Zea mays L.) starch. Scribe® paper was used as substrate or adherent. The CCD consisted of 36 experiments (including 12 central points). The second-order regression models of the response surface method, used to predict the response variables, exhibited a high correlation between the data obtained and the predicted data, and were thus considered reliable to optimize the mechanical properties for peel strength and shear strength of the Ramon starch adhesives. Starch content, hydrolyzing agent content and the cooking temperature of the adhesives proved to be the most significant factors affecting peel strength and shear strength of the adhesives of both the Ramon and corn starch. Moreover, the interactions of Starch-NaOH and Starch- Temperature were found to be the most significant in the adhesive properties in both adhesives. The mechanical properties (peel strength and shear strength) of both adhesives increased until reaching approximately their temperatures of gelatinization (T RAMON GEL = 83 °C, T GEL CORN = 72 °C). At higher temperatures, the mechanical properties of the adhesives diminished. The results of this study show that the adhesive prepared with the Ramon starch presents adhesive properties similar to those of an adhesive prepared with corn starch. This would imply that the Ramon starch is a viable alternative to substitute corn starch in industrial applications not relating to food production. 1. Introduction Starch, which is one of the most abundant polysaccharides of the plant kingdom, is used by the plants as a reserve source and for energy storage, and can be found in a large variety of species (cereals, legumes, tubers and some physiologically immature fruits) [26]. For many years, the main source for the procurement of starch has been corn [28], potatoes [27], tapioca [8], etc., all of which are cultivated as food sources for the population in many developing countries; thus any scarcity of these products can lead to an increase in world hunger. Due to this situation, scientists are now focusing their attention on the extraction of this polysaccharide from non-conventional sources which do not compete with human food production, while serving as raw material in industrial processes. The Ramon tree (Brosimum alicastrum swartz), one of the more dominant trees in the forests of Mexico and Central America [13], takes its scientific name from the Greek “brosimos”, which means “edible”. In Mexico and Guatemala, it is generally known as the Ramon, and this name, which derives from the Spanish verb ramonear (to browse), refers to the fact that cattle and other domestic animals consume the seeds and leaves. Recently, [37] and [32] obtained and characterized starch from the fruit of the Ramon tree, demonstrating that it is possible to obtain starch from this non-conventional source. On the other hand, given that starch is a renewable, biodegradable and highly available material at a low cost [18], one of its most important industrial applications is in the elaboration of pastes, adhesives and glues [48]. The use of starch and its derivatives such as adhesives, has been employed over many centuries (e.g. The Egyptians) [35]. However, its adhesive properties are highly question- able when used in a raw state [46]. In order to resolve this problem, a number of methods have been reported to modify the starch for use as an adhesive, which include treatments with acids and bases, thermal http://dx.doi.org/10.1016/j.ijadhadh.2016.11.004 Accepted 1 November 2016 ⁎ Corresponding author. E-mail address: avaladez@cicy.mx (A. Valadez-Gonzalez). International Journal of Adhesion & Adhesives 73 (2017) 28–37 0143-7496/ © 2016 Elsevier Ltd. All rights reserved. Available online 13 November 2016 crossmark