Phase Separation Progress Of PS/PVME Blend System Revealed By Raman Mapping Image Technique

The properties of polymer blend materials is strongly determined by the chemical constitution and morphological structure of the polymer heterogeneous system in microcosmic scale. The compatibility and phase separation of blend system directly influence its morphology and structure, thus further influence the properties of the prepared materials. Acquisition of the microcosmic information about poly-phase/poly-composition polymer blend phase separation contribute to optimize the phase structure, phase size and function of ultimate materials. Raman spectrum as an in situ non-damage detection, can provide molecular vibrational information and can be very sensitive to the conformation of polymer molecule chain and interaction between chains, is widely applied to the study of polymer blend’s properties such as crystallization, distribution of phase state and interface diffusion. Raman mapping image technique can provide both the Raman spectrum of each scanning point of sample and the chemical image of the scanning domain with high-space resolution ratio (about 1μm), it’s a practicable method to study polymer blend system. The main results are summarized as follow:(1) Using Raman mapping image technique to study the morphology and chemical distribution of polymer blend PS/PVME=20/80,50/50,80/20, one of the blend systems with Low- Critical Solution Temperature (LCST), annealed at 120℃ with different annealing time. The data result manifests that different compositions ratio of the blend system under the same annealing temperature result in different phase separation mechanism. Blend PS/P VME-20/80 firstly went through nucleating phase separation, then the PS phase connect as network structure, which may be viscoelastic phase separation that has recently been reported. Blend PS/PVME-50/50 went through spinodal phase separation and blend PS/PVME-20/80 generally didn’t go through phase separation under the 120℃ annealing. The result is consistent with the phase image of blend PS/PVME.(2) Using Raman mapping image technique to further study the chemical distribution and the phase separation dynamics of polymer blend PS/PVME=5/95,15/85,35/65 at 105℃ and 135℃ respectively with different annealing time. Applying Cahn-hillard equation and the notion of structure function on discussing the possibility of scaling phase separation on the concentration fluctuation and scaling the phase separation of polymer blend PS/PVME=5/95,15/85,35/65at 105℃ and 135℃ respectively with different annealing time. Achieving Preliminary establishment of the model for scaling phase separation process of polymer blends with known factors based on Raman mapping techniques.