PMMA/PVBブレンドのゼロ複屈折組成と配向複屈折

摘要

Blends of poly (methyl methacrylate) (PMMA) and poly (vinyl butyral) (PVB) exhibit zero-birefringence due to the compensation of negative birefringence of PMMA and positive birefringence of PVB, respectively. The zero-birefringence composition of drawn-quenched specimens was found to be quite different from that induced by deformation at room temperature. The zero-birefringence composition was calculated by the additivity of the orientation and/or distortion birefringence of the neat component polymers, which were evaluated by the curve fitting procedures of the relaxation birefringence and relaxation stress. The calculation results revealed that the birefringence of the drawn-quenched specimens is attributed to the orientation birefringence in the glassy state while that of the deformation at room temperature is attributed to both orientation and distortion birefringence at room temperature.%ポリメタクリル酸メチル（PMMA)は負の複屈折，ポリビニルブチラール（PVB)は正の複屈折をもっため，それらをブレンドすれば複屈折をゼロにさせることができる.PMMA/PVBブレンドのゼロ複屈折組成を調べたところ，熱延伸•急冷試料と室温延伸試料ではまったく異なる組成で複屈折がゼロになることが見いだされた.PMMA単体とPVB単体の一軸延伸後の応力•複屈折緩和測定の解析結果から配向複屈折とひずみ複屈折を求めて，それらの加成値によりゼロ複屈折組成を算出した結果，熱延伸•急冷試料の複屈折はガラス状態の配向複屈折に起因するのに対して，室温延伸試料の複屈折は室温の配向複屈折とひずみ複屈折の両者に起因することが明らかになった.