Effect of Type of Amine Salt and Surfactant on the Water Sorption and Flexural Properties of Modified Zeolite/Polyester Composites

Abstract

Natural zeolite, an abundant clay with porous solids based on silica, is modified with amine salt and surfactant, and incorporated as filler for polyester to produce modified zeolite/polyester (MZP) composite. A general factorial design of experiment is implemented with two factors (type of amine salt and type of surfactant) varied at three levels each. The amine salts are tetra- (TDA), hexa-, and octadecyl dimethylamine chloride while surfactants are stearic acid (SA), glycerol monostearate, and cocamide diethanolamine (CDEA). Water sorption and flexural testing are performed on MZPs. Results show that natural zeolite treated with SA exhibits improved hydrophobicity of MZPs, resulting to lower water uptake as compared to untreated natural zeolite. However, water sorption in MZPs is higher than in pure polyester due to difference in hydrophobicity. Flexural modulus of MZP is highest using TDA + CDEA due to enhanced filler-to-matrix compatibility. Meanwhile, break stress is highest for untreated zeolite filler due to the high stress resistance of rigid natural zeolite. Analysis of variance shows water sorption to be significantly affected by the type of surfactant, while break stress is significantly higher using amine salt with shorter chain length.