Mohammad Valizadeh - Institute of Polymeric Materials, Polymer Engineering Department, Sahand University of Technology, P.O.Box ۵۱۳۳۵-۱۹۹۶, Tabriz, Iran
Mostafa Rezaei
Alireza Eyvazzadeh

Rigid PU/Clay nanocomposite foams with water as chemical blowing agent were prepared with modified layered silicate clay (Cloisite 30B). The dispersion of organoclay in polymer matrix was studied using a small angel X-ray diffraction (XRD) method. XRD patterns suggested that the organoclay is uniformly dispersed in polymer matrix. FTIR studies confirm the reaction between isocyanate and organoclay. The microstructure of foams was investigated using an optical microscope. Results indicated that increasing the nanoclay content decreased the cell size as well as narrowed the cell size distribution. Furthermore the thermal conductivity results demonstrated that increasing nanoclay content decreased the thermal conductivity coefficient (k-factor) thus improved the thermal insulation properties of rigid PU foams. Mechanical examinations were conducted in compression mode on rigid polyurethane foams, at constant foam density (31-33kg/m3) and the results revealed that compressive strength and modulus of nanocomposite foams continuously decrease by addition of organoclay.

Water blowing agent, rigid polyurethane foam, Organoclay, Microstructure, Mechanical properties, Thermal conductivity