Exploring time-dependent structural changes during the cold crystallization process of isotactic polystyrene by infrared spectroscopy and multivariate curve resolution.

摘要: The present study attempts an application of Fourier transform infrared (FT-IR) spectroscopy in conjunction with multivariate curve resolution (MCR) techniques to explore the structural evolution isotactic polystyrene (iPS) during cold crystallization process. focus is placed on performance MCR techniques, e.g., orthogonal projection (OP), alternating least squares (ALS), and fixed-size moving window evolving factor analysis (FSMWEFA), interpretability spectral changes investigated chemical As a result, valuable information conclusions about iPS process can be extracted: when amorphous phase changes, ordering phenyl rings takes place first, then polymer chains adjust their local conformations form short 31 helix structures. Furthermore, according intensity profiles variations, proceeds more intensely than formation ordered chains, occurs even induction period. variations resulting from conformational helical structures depend sequence length chains: longer chain is, smaller corresponding band are. It has been demonstrated that combination FTIR chemometric very promising for polymers. powerful tool analyzing visualizing data integrating them other information, making amenable interpretation order molecular dynamics