Investigation of thermal properties of PUF/clay nanocomposites

•The thermal properties of phenol–urea–formaldehyde (PUF) /organoclay nanocomposites synthesized at various organoclay ratios were investigated by using their DSC thermograms, FT-IR spectra, and HRTEM images.•It was determined that low organoclay amounts may lead to a cross-linked framework being more predominant than a linear form.•At low organoclay content, partially exfoliated structure but at high organoclay content, heterogeneously distributed intercalated and tactoidal structures were observed. This study aims to investigate the thermal properties of phenol–urea–formaldehyde (PUF)/organoclay nanocomposites synthesized at various organoclay ratios by using their DSC thermograms, FT-IR spectra, and HRTEM images. From these analyses, it has been concluded that at low organoclay ratios, the platelets exfoliated of organoclay, which dispersed homogenously in the polymer matrix, created a positive effect in conformational arrangement as suitable to crystallization of PUF chains. DSC analyses revealed that two endotherms in all thermograms imply the presence of linear UF, PF, and PUF chains together. Low organoclay content may also lead to a cross-linked lattice, being more predominant than the linear chain arrangement.