Radiation-Induced Structural Transformations of Siloxane Diblock Copolymers

An X-ray Diffraction Study of γ-Irradiated Siloxane Block Copolymers

“…Data obtained in an electron-microscopic study of siloxane block copolymers [3] and characteristics obtained by DSC [5] correlate with the data of X-ray diffraction analysis.…”

“…According to data obtained by differential scanning calorimetry (DSC), peaks due to cold crystallization ( T = -80° C) and melting ( T ~ − 50° C) were observed in the initial diblock copolymers, as distinct from the multiblock copolymers. Note that, after the irradiation of siloxane diblock copolymers to a dose higher than 100 kGy, which corresponds to the dose of 1 e-mail: pankratova@rc.chem.msu.ru the onset of gelation, two melting peaks appeared in the DSC curve at the temperatures T m1 = -52 ° C and T m2 = +20 ° C. As the dose was increased to 400 kGy, the crystallization temperature T c increased to -35° C, and the melting temperature T m1 increased to +27 ° C; the second melting peak was not observed at radiation doses higher than 100 kGy [4,5]. In [4,5], we first noted the difference between diblock and multiblock copolymers.…”

“…Previously, the effect of γ -irradiation on multiblock and diblock copolymers was studied using electron microscopy [3,5]. It was found that multiblock copolymers in the initial state are globular matrices with densely arranged globules, which became somewhat squeezed but remained practically unchanged upon irradiation.…”