Abstract
Effects of drawing and annealing on dynamic mechanical properties of poly(trimethylene terephthalate)(PTMT) fibers were investigated. PTMT obtained via polycondensation reaction of 1,3-propanediol and terephthalic acid was spun on a pilot scale extruder at the spinning speed of 1000m/min (UDY-1) and drawn to various draw ratios. It was also spun on a laboratory scale extruder at the spinning speed of 143m/min (UDY-2) and subsequently annealed at a temperature between 6$0^{\circ}C$ and 18$0^{\circ}C$ for 1 hour. Dynamic mechanical properties of these PTMT fibers were studied using dynamic mechanical analyzer(DMA). It was found that the glass transition temperature ($\alpha$-relaxation) of UDY-1 determined by loss modulus is about 45$^{\circ}C$ and increases with increasing draw ratio. The glass transition temperature of UDY-2 was about 43$^{\circ}C$ and it increased up to the annealing temperature of 10$0^{\circ}C$ and then decreased. The apparent activation energy of $\alpha$-relaxation of PTMT fiber was determined to be about 342~396 kJ/mol which was lower than that of crystalline unoriented PET (ca. about 520kJ/mol). This suggests that the molecular chain of PTMT has lower energy barrier than that of PET and therefore the glass transition temperature of PTMT is lower than that of PET.
