Reactivity of isophorone diisocyanate in fabrications of polyurethane foams for improved acoustic and mechanical properties

Polyurethane foams attract great attentions in various applications due to their superior materials properties. Foam structure is strongly related to the initial reaction rate of polymerization process. The effects of isocyanate (NCO) ratios between aromatic and aliphatic types on acoustic and mechanical properties were investigated. Highly electrophilic carbon atoms and less sterically hindered planar structure in aromatic NCO groups showed higher reactivity than in aliphatic nonplanar structure, and consequently the pore size and numbers decreased with increasing aliphatic contents from reduced pore formations due to high asymmetry molecular arrangements. The highest acoustic activity was also achieved at optimum aliphatic content.