Dynamic mechanical properties of a series of crosslinked polyester resins have been determined by a freely oscillating torsional pendulum in the temperature range - 175 to 270°C. The materials were obtained by adding various amounts of two different flexibilizers, one crosslinkable and the other non-crosslinkable with itself, to a basic polyester resin. The results confirm the indications, derived from previous d.s.c. measurements, that the addition of the crosslinkable flexibilizer gives substantially homogeneous network structures, while the addition of the non-crosslinkable flexibilizer gives heterogeneous polyphasic network structures. It has also been shown that the lowering of the glass transition temperature by the addition of the crosslinkable flexibilizer is attributable partly to a reduction in the degree of crosslinking and partly to the effect of variation in chemical composition.
Посилання на статтю:
Characterization of crosslinked polyester resins by dynamic mechanical properties / Giuseppe Tieghi, Marinella Levi and Andrea Fallini // Polymer. – 1992. – Vol 33. – P. 3748-3750.