Rheo‐optical fourier‐transform infrared spectroscopy of polymers 16 orientation and strain‐induced conformational regularity of poly(dimethylsiloxane) networks during cyclic elongation and recovery

Two SiO2‐filled poly(dimethylsiloxane) networks with different molar masses Mc (22000 g/mol and 33000 g/mol) between the junctions have been investigated by simultaneous mechanical and Fourier‐transform infrared (FTIR) spectroscopic (rheo‐optical) measurements to monitor the structural changes in cyclic elongation‐recovery procedures. Higher polymer chain orientation was observed at corresponding elongations for the low‐Mc network, but due to the higher extensibility appreciable strain‐induced conformational regularity occurred only in the high‐Mc material. Differences with reference to unfilled model networks are pointed out.