TMPTA

Abstract: Photoinduced frontal polymerization was performed on a variety of multifunctional (meth)acrylates, and evaluation of the effect of monomer structure on the ability to sustain a traveling front was made. Photo-DSC was used to measure the photopolymerization rate of each monomer at 25 °C. The results were correlated with their ability to initiate and sustain a traveling front polymerization. The start time and the front velocity of each (meth)acrylate that could initiate/sustain a front photolytically were measured. The results clearly demonstrate that the molecular weight per double bond is directly related to the front velocity. Trimethylolpropane triacrylate (TMPTA), which exhibited the fastest front velocity, was evaluated in depth to determine the effect of varying the photoinitiator and thermal initiator on the frontal polymerization rate. When a multifunctional thiol was added to TMPTA, the start time was dramatically reduced and the velocity increased for low thiol concentrations. However, the veloc...

Abstract: A hybrid organic-organic urethane acrylate oligomer was synthesized by the reaction of polypropyleneglycol (PPG), 2,4-toluene diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) using dibutyltin dilaurate (DBTDL) as a catalyst. The urethane acrylate oligomer’s structure was characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). Two UV-curable coatings were prepared by blending the urethane acrylate oligomer, a reactive monomer (1,6- hexanediol diacrylate (HDDA) or trimethylol propane triacrylate (TMPTA)) and a photoinitiator (2,2-dimethoxy-2-phenyl acetophenone). The UV curing process of such coatings was monitored by FT-IR and determination of the gel fraction. It was found that as the UV dose increased, the specific peaks at 1635 cm -1 and 810 cm -1 , related to the carboncarbon double (C=C) bond, decreased. Gel fraction of the cured coating film was found to increase with increasing radiation time. Thermal properties of the cured coating were also investigated using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA).