Uniaxial and Biaxial Stretching of Poly (Methyl Methacrylate): Mechanisms, Property Enhancement, and Aerospace Applications

Abstract

Poly (methyl methacrylate) (PMMA) is a widely used transparent polymer in aerospace applications owing to its low density, excellent optical clarity, and environmental stability. However, the inherent brittleness and limited impact resistance of amorphous PMMA restrict its performance under extreme service conditions. Recent advances in thermomechanical stretching have demonstrated significant improvements in the optomechanical properties of PMMA through molecular chain orientation. This review critically examines the effects of uniaxial and biaxial stretching on the structural evolution, mechanical strength, toughness, impact resistance, and optical performance of PMMA. Various industrial and laboratory-scale stretching techniques are discussed, along with their influence on anisotropy and property enhancement. Comparative analyses between cast and stretched acrylics highlight the superior durability, crazing resistance, and thermal stability achieved through orientation processes. The current state-of-the-art applications of stretched PMMA in aerospace transparencies, including canopies and windshields, are presented. Finally, key challenges and future research directions for high-performance transparent polymers are outlined.