Vibrational overtone initiated polymerization of ethylene glycol dimethacrylate and acrylonitrile, vibrational overtone initiated copolymerization of styrene/trimethylolpropane propoxylate triacrylate.

摘要

Laser vibrational overtone initiated polymerization of ethylene glycol dimethacrylate (EGDMA) has been demonstrated using two initiators, benzoyl peroxide (BP) and 2,2′-(azobis)isobutyronitrile (AIBN). Excitation of the initiator occurs through absorption of a single photon by the fifth CH stretching vibrational overtone transition at 604 nm (16556 cm −1) for BP and 628 nm (15924 cm−1) for AIBN. Monomer conversion was followed quantitatively by monitoring the intensity change of the vinyl combination band at 6169 cm−1 in the first overtone spectrum of EGDMA. Considering the concentration, the molar extinction coefficient and laser power, AIBN was a factor of 3.2 more efficient than BP for vibrational overtone polymerization. In both cases, the rate of polymerization depends on the excitation wavelength. The influence of the initiator concentration and the photolysis duration was also studied.; Vibrational overtone activated polymerization of acrylonitrile (AN) has been demonstrated using two initiators, benzoyl peroxide (BP) and 2,2 ′-(azobis)isobutyronitrile (AIBN). Excitation of the fifth vibrational overtone of the CH stretch of AIBN at 627 nm and BP at 604 nm initiates the reaction. Monomer conversions were monitored by a gravimetric method. In both cases, the wavelength selectivity was investigated by irradiating the monomer/initiator mixtures at the absorption maximum of the initiator, the absorption maximum of the monomer, and at a wavelength (580 nm for AN/AIBN and 625 nm for AN/BP) where neither the initiator nor the monomer absorbs light. For the AN/AIBN mixture, after 48 hours the monomer conversion for the irradiation on the peak absorption of AIBN (627 nm) is about 1.5 times larger than for the irradiation at 580 nm. For the AN/BP mixture, after 48 hours the monomer conversion for the irradiation on the peak absorption of BP (604 nm) is about a factor of 2 larger than for the irradiation at 625 nm. The influence of the initiator concentration was also investigated.; Vibrational overtone spectra of trimethylolpropane propoxylate triacrylate (TMPPTA) monomer and corresponding polymer were recorded in the spectral range 4500–15000 cm−1. All spectra were analyzed in terms of local mode theory. Peaks corresponding to transitions for the vinyl, methylenic and methyl types of the CH stretch were identified using Birge-Sponer plot. The anharmonicities and mechanical frequencies for each progression in monomer and polymer are presented.; Vibrational overtone copolymerization of TMPPTA/styrene with BP has been demonstrated using extracavity irradiation.; Different ratios of monomer mixtures from 10:90 to 90:10 TMPPTA/styrene were used. It was found that the monomer conversion at 72hr reaches the highest when the ratio of monomer mixture is 50:50 TMPPTA/styrene.; A chromate corrosion test and followed by SEM were conducted to investigate the structure and corrosion resistance of the TMPPTA/styrene photo-copolymer. The larger the percentage of TMPPTA in monomer mixture, the larger the holes created by corrosion in copolymer, and the weaker corrosion resistance of the polymer.