A Thermal Degradation Study of Insulation Materials Extruded Polystyrene

AbstractThis paper presents a research on the thermal degradation of typical polymer insulation materials extruded polystyrene (XPS) under both oxidizing gas air and non-oxidizing gas nitrogen. The Kissinger-Akahira-Sunose method was employed to calculate the activation energy values according to thermogravimetic analysis (TGA) results. Thermal degradation characteristics of XPS were studied by using thermogravimetry and differential scanning calorimetry (TG-DSC) hyphenated technique. XPS follows a two-stage and three-stage weight loss during the entire process under nitrogen and air, respectively. Evolved products of XPS and the degradation mechanism in helium were investigated with pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) method. The results reveal that styrene monomers are the dominate products of XPS degradation. Methylbenzene, α-methyl styrene, dimer and some other oligmers of styrene are also detected

Neutron Density Distributions of Neutron-Rich Nuclei Studied with the Isobaric Yield Ratio Difference

The isobaric yield ratio difference (IBD) between two reactions of similar experimental setups is found to be sensitive to nuclear density differences between projectiles. In this article, the IBD probe is used to study the density variation in neutron-rich $^{48}$Ca. By adjusting diffuseness in the neutron density distribution, three different neutron density distributions of $^{48}$Ca are obtained. The yields of fragments in the 80$A$ MeV $^{40, 48}$Ca + $^{12}$C reactions are calculated by using a modified statistical abrasion-ablation model. It is found that the IBD results obtained from the prefragments are sensitive to the density distribution of the projectile, while the IBD results from the final fragments are less sensitive to the density distribution of the projectile.Comment: 3 figure