Influence of the chemical functionalization of titanium oxide nanotubes on the non-isothermal crystallization of polypropylene nanocomposites

The surface of titanium oxide nanotubes (TiNTs) was chemically modified after synthesis to determine their influence on the non-isothermal crystallization of polypropylene nanocomposites compared to pristine titanium oxide nanotube-reinforced systems. Pimelic acid (PA) was used to carry out the chemical functionalization (TiNT-PA). The FTIR spectrum revealed that PA successfully bound to the TiNT surface due to the appearance of new vibrational bands at 29834, 2868, 1578, and 1407 cm(-1). After the functionalization process, the morphology of TiNT remained unchanged according to TEM images. In addition, the new filler showed high thermal stability when subjected to TGA (between 320 and 450 degrees C). DSC studies were carried out to investigate the influence of this chemical functionalization on the crystallization behavior of the nanocomposites. The nanocomposites with the modified TiNTs showed more significant shifts of the crystallization temperature peaks with large heterogeneous nucleation. According to Jeziorny's analysis, the effect of fillers was only observed for the functionalized nanotubes with the lowest crystallization times, while the systems with pristine TiNT practically remained the same. This behavior is attributable to the fact that the acid's presence reduced agglomeration and improved the efficiency of the nucleation activity. Mo's model results confirmed that the heat flux requirements of the crystallization process were lower for the nanocomposites reinforced with TiNT-PA as they act better as heterogeneous nuclei. Then, they provide the surface area to serve as a nucleation center and help crystallize the polypropylene due to the aliphatic chain of the organic molecule. [GRAPHICS]

Automated summary

This study investigated the effect of chemically modified titanium oxide nanotubes on the non-isothermal crystallization of polypropylene nanocomposites. The modified nanotubes showed significant shifts in crystallization temperature peaks and improved heterogeneous nucleation. The presence of the modifier reduced agglomeration and improved nucleation efficiency. The chemical modification of titanium oxide nanotubes plays an important role in enhancing the performance of the composite materials.