Thermal and mechanical analysis of a photopolymerization process

摘要: Abstract Network formation by photopolymerization has been studied for tetra-ethyleneglycol diacrylate (TEGDA) using isothermal differential scanning calorimetry (d.s.c.) and dynamic mechanical thermal analysis (d.m.t.a.). Owing to vitrification, the polymerization does not go completion at room temperature. The ultimate conversion as measured d.s.c. seems depend on light intensity. This effect is caused self-heating. In thin layers used with temperature rise less than 3 K. However, measurements show that especially low intensities process continues a considerable time rate which cannot be detected At equal doses temperatures of maximum loss, T (tan δ max ), were observed same. D.m.t.a. partially polymerized samples TEGDA reveals an increase Young's modulus due postcure near 120°C. Parallel d.s.c.-extraction experiments this aftercure requires presence free monomer. Near end monomer exhausted only crosslinks are formed. ) then increases markedly double-bond conversion. Trapped poly(TEGDA) radicals decay in dark single-line electron spin resonance spectrum, presumably CH 2 O∗ radicals. After 21 h most have disappeared.