ELECTRON-MICROSCOPIC INVESTIGATIONS OF MORPHOLOGY AND STRUCTURE FORMATION OF POLYMERS

Techniques of electron microscopy and specimen preparation of polymers for studying morphology and interfacial layers are briefly reviewed, including a discussion of general problems of electron microscopic inv estigations of polymers arising from irradiation sensitivity and low c ontrast. To improve contrast, some irradiation-induced effects are app lied to reveal arrangement of lamellae and intralamellar defects in se micrystalline polymers (polyurethane-PU and polyethylene-PE), Structur e formation has been studied in PE using a special technique of irradi ation-induced fixation in the melting range. Using this technique, str ucture formation processes in polymer blends [e.g., low-density PE/hig h-density PE (LDPE/HDPE) blends] can also be studied. Using in situ de formation tests in the electron microscope, strength of interfaces is determined in several polymer combinations. As a consequence, the stru ctural details which are important for mechanical properties can be de fined.