Optimized formulation of an oxidative curing system for liquid polysulfide sealants used in fuel tanks by D‐optimal design method

Abstract

In this work, the effective parameters in liquid polysulfide curing system were optimized by D-optimal design method. Five main components in the formulation, carbon black, vulcanizing agents (MnO 2 , Na 2 Cr 2 O 7 , and PbO 2 ), CaCO 3 , fumed silica, and chlorinated paraffin, were selected. Mechanical and chemical properties of the samples were investigated. The results showed that tensile strength, hardness, viscosity, and optimum cure time (t 90 ) presented a suitable coordination with reduced quadratic model. For elongation at break and swelling tests, reduced two-factor interaction (2FI), and for peel strength, a linear model showed the best correlation. To achieve the desirable properties for liquid polysulfide sealants used in fuel tanks, an optimized amount of the above components in the formulation were used. Finally, MnO 2 curing system, compared with Na 2 Cr 2 O 7 and PbO 2 , was selected as the best choice.

Application of D‐optimal experimental design in nano‐sized ZSM‐5 synthesis for obtaining higher crystallinity

“…In this research, a 95% confidence interval has been used to evaluate the parameters signification. Therefore, a probability value (P‐value) of 5% would be the significant level in F‐tests for interpretation of the effects . In this study, ANOVA was employed in order to determine which of the factors have a greater influence on the relative crystallinity.…”

Effect of Blend Ratio and Testing Rate on the Adhesion Properties of Epoxidized Natural Rubber (ENR 25)/Styrene–Butadiene Rubber (SBR) Blend Adhesive

“…For a fixed ENR blend ratio, loop tack increases with coating thickness. This observation is attributed to the presence of higher amount of adhesive which increases the mechanical interlocking of adhesive molecules in the porous or rough substrates [15] as coating thickness is increased. Figure 4 shows the dependence of loop tack on the of rate of testing at the optimum ENR 25 blend ratio for 30 m and 120 m coating thickness.…”

Adhesion properties of (epoxidized natural rubber)/(ethylene‐propylene‐diene rubber) blend adhesive: Effect of blend ratio and testing rate

“…This observation is associated with the presence of higher amounts of adhesive in the thicker sample. The presence of a larger amount of adhesive means more mechanical interlocking of adhesive molecules in the porous or rough substrates , which increases the tack for higher coating thickness. The effect of rate of testing on the tack behavior is shown in Fig.…”