Netsu Sokutei, 29 (5), p. 192, (2002)


DSC-FTIR同時測定による部分相溶系ポリフッ化ビニリデン ブレンドの等温結晶化過程と多重融解ピークの解析

The Simultaneous DSC-FTIR Study on the Isothermal Crystallization and the Multiple Melting Behavior of the Partially Miscible Poly(vinyliden fluoride) Blends

部分相溶系であるポリフッ化ビニリデン(PVDF)とイソタクチックメタクリル酸メチル(isoPMMA)のブレンドの等温結晶化過程と融解過程をDSC-FTIR同時測定で検討した。PVDFのTGTG'(α型)とT3GT3G'(γ型)コンホメーションのCH2横揺れ振動に帰属される795と810 cm-1の吸光度を各結晶型の結晶化指標として用いた。等温結晶化初期にはα型が生成し最大値を示した後,γ型が生成した。α型とγ型のIR吸光度変化の関係からα-γ転移のメカニズムを検討した。PMMA組成が0.2以下のブレンドではγ型はα型からの固相転移で生成したが,PVDFでは固相転移に加えて過冷却液体から直接γ型が結晶化することが明らかになった。等温結晶化後の昇温速度では多重融解ピークが観察され,各ピークはα型の融解,α型の融解・再結晶化で生成したγ型の融解ならびに等温結晶化過程で生成したγ型の融解であることがわかった。
Isothermal crystallization and melting behaviors of poly(vinilidene fluoride) (PVDF) and isotactic poly(methyl methacrylate) (isoPMMA) blend, partially soluble blend system, were investigated by the simultaneous DSC-FTIR method. The absorption bands at 795 and 810 cm-1, which were assigned respectively to CH2 rocking vibration mode of PVDF in TGTG' (α-form) and T3GT3G' (γ-form) conformation, were used as an indication of each crystal form. During the isothermal crystallization, the α-form crystallized in the initial stage of crystallization, γ-form crystallized after the maximum of &alpha-form content. The transition mechanism from α-form to γ-form was estimated from the linear relationship between IR absorbance corresponding to the decrease rate of α-form and the increase rate of γ-form. The γ-form was transformed from the α-form in the solid state for the blends with PMMA content (fPMMA) lower than 0.2, and the γ-form was crystallized from the super-cooled liquid state addition with the solid state transition from the a-form for PVDF. The multiple melting peaks were observed by heating immediately after isothermal crystallization. Each melting peaks were identified as the melting of α-form, the melting of γ-form produced by the melt-recrystallization of α-form, and the melting of γ-form transformed from α-form in the solid state during the isothermal crystallization.