Structure-property relationships in novel polydiacetylene-containing oligoester: Polyolefin blends

The paper describes thermal and mechanical properties of a series of novel blends prepared using a two-stage process which invloved solution blending a specially-synthesised diacteylene-containing oligoester (DOE) with a semi-crystalline poly[ethylene-co-(vinyl acetate)] (EVA), followed by conversion of the DOE to a polydiacteylene-containing oligoester (cp-DOE) by in situ thermal cross-polymerisation during moulding. Moulded blends range from ductile to brittle materials and give intense Raman spectra in which the C≡C stretching band at ∼2100 cm-1 is well-defined and shifts to lower wavenumber when the blends are subjected to tensile stress. For each blend composition, shifts in wavenumber were used to determine local stress in the cp-DOE component independently of the overall stress applied to blend.