Crystallization, melting behavior, and crystal structure of reactive, intumescent, flame-retardant polypropylene

Polypropylene (PP)/2-({9-[(4,6-diamino-1,3,5-triazin-2-yl) amino]-3,9-dioxido-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecan-3-yl} oxy) ethyl methacrylate (EADP) composites were prepared by the blending of PP with EADP as a new flame-retardant material. The nonisothermal crystallization and melting behaviors of composites were investigated with differential scanning calorimetry (DSC). Their crystal morphologies and structures were studied by polarized optical microscopy (POM) and X-ray diffraction (XRD), respectively. The DSC results show that the addition of EADP increased the crystallization onset temperature, crystallization peak temperature, and degree of crystallinity of PP in the PP/EADP composites. The melting onset temperature and melting end temperature of the PP/EADP composites decreased slightly, whereas the melting peak temperature of the PP/EADP composites increased. The POM results show that the addition of EADP greatly reduced the crystal size of PP in the composites. When the content of EADP in the PP/EADP composites was increased, the crystal size of PP became smaller. The XRD results indicate that the addition of EADP changed the crystal structure of PP in the PP/EADP composites, which exhibited both α-form and β-form crystal structures. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41374.