The aim of this study is to investigate the potential of low-density thermal insulation materials obtained from corn pith or sunflower pith. This type of material is usually obtained by adding synthetic or natural binder. In this study,corn pith and sunflower pith are subsequently thermocompressed without the addition of binder. The addition of water coupled to thermocompression would allow the extraction of soluble compounds from the pith which acts as a binder within the material. Physical and biochemical characterizations were previously carried out on the two piths studied before implementation in materials. They highlight common properties, such as a low density as well as a capacity to control hygrometry explained by the predominant presence of a honeycomb structure. The presence of fibers traversing the corn pith observed by microscopy differs from the 100% alveolar structure of the sunflower pith. These differences impact the final properties of the particleboard.