Polypropylene containing Ti- and Al-polyhedral oligomeric silsesquioxanes: crystallization process and thermal...

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Polypropylene (PP) is a widely used thermoplastic polymer.
• Polyhedral Oligomeric Silsesquioxanes (POSS) are nanoscale cage compounds with tunable properties.
• Incorporating POSS into polymer matrices can enhance material performance.

Purpose of the Study:

• To prepare and characterize isotactic polypropylene (PP) composites containing titanium (Ti)-POSS and aluminum (Al)-POSS.
• To investigate the effects of different metal centers in M-POSS on the morphology, crystallization, and thermal behavior of PP.
• To understand the influence of M-POSS on the thermal degradation pathways of PP.

Main Methods:

• Dispersion of Ti(IV)-isobutyl-POSS and Al(III)-isobutyl-POSS in PP.
• Morphological analysis using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM).
• Crystallization and thermal behavior assessment via X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA).
• Spectroscopic characterization using FTIR and Raman spectroscopy.
• Thermal degradation analysis using Gas Chromatography/Mass Spectrometry (GC/MS).

Main Results:

• Ti-POSS and Al-POSS exhibited distinct effects on the thermoxidative behavior of the PP matrix.
• Ti-POSS demonstrated significant stabilization of PP during heating in air, while Al-POSS showed limited stabilization.
• Ti-POSS influenced the PP crystallization process, directing it along specific crystallographic pathways.
• The metal center of M-POSS plays a crucial role in determining the degradation pathway of PP.

Conclusions:

• Metal-POSS additives can selectively modify the thermal stability and crystallization behavior of polypropylene.
• Ti-POSS offers superior stabilization effects for PP compared to Al-POSS.
• The choice of metal center in M-POSS is critical for tailoring the performance and degradation characteristics of PP composites.