The influence of temperature and photoinitiator concentration on photoinitiated polymerization of diacrylate monomer

Abstract

The behavior of p-methoxybenzoyldiphenylphosphine oxide, previously synthesized, as a photoinitiator for the polymerization of diacrylate monomer, in the presence of 3 % (w/w) tertiary amine (triethyl amine) as synergist additive, was studied. The influence of temperature in the range 30-90 • C at 3 % (w/w) photoinitiator concentration and the influence of the photoinitiator concentration in the range 0.5-3.5 % (w/w) at 30 • C was investigated by differential scanning photocalorimetry (photo-DSC). In all experiments the photopolymerization was performed at constant light intensity (3 mW cm −2 ). The maximum conversion was obtained at temperature of 90 • C at 3 % (w/w) photoinitiator concentration and 3 % (w/w) triethyl amine. The optimal concentration of photoinitiator to obtain maximum conversion was 3 % (w/w), at 30 • C. No thermal polymerization occurred at higher temperature.

Recent Research Progress on Lignin-Derived Resins for Natural Fiber Composite Applications

“…In the series without solvent, VD-TPOL (3 mol%) showed higher Gʹ around 18.1 MPa in within 6s than VD-TPOL (1 mol%) and VD-TPOL(5 mol%), while Gʹ of VD-TPOL (3 mol%) reached up to 11.3 MPa within 12 s in the presence of a solvent, which means the solvent decreased the cross-linking rate due to the chain transfer agent [ 118 ]. In the case of VDM resin, the Gʹ value for VDM-TPOL (5 mol%) was higher in the presence of solvent than VDM-TPOL (1 mol%) and VDM-TPOL (3 mol%), which was due to more cross-linking on the surface layer and the slow polymerization [ 119 , 120 ].…”

Preparation of solvent resistant supports through formation of a semi-interpenetrating polysulfone/polyacrylate network using UV cross-linking – Part 1: Selection of optimal UV curing conditions

“…To conclude, the hypothesis as stated above with respect to the optimum PhIn content could neither be rejected nor accepted as an optimum could still be apparent for lower PhIn concentrations although 3 wt% is generally used in literature [24,58,63].…”

“…Therefore, the investigated radiation time range was shortened to 105 s. It was suggested that the efficiency of absorption of the incident radiation by the PhIn increases with the PhIn concentration, resulting in more radicals. A possible explanation, according to [24,45,[58][59][60], is that increasing the PhIn concentration results in a large amount of free radicals, which quickly generate a polymer network.…”

Development of Photocurable Polyacrylate-Based PolyHIPEs and the Study of the Kinetics of Photopolymerization, and of Their Thermal, Mechanical and Hydrocarbon Absorption Properties

“…All formulations displayed a similar photopolymerization rate, when the concentration of photoinitiators was varied in the T-E (1:3) HIPEs (Figure 4b), though the HIPEs with 2.0 mol% of both photoinitiators displayed lower reactivity, while the formulation with 0.25 mol% of both photoinitiators showed the highest. Due to the high reactivity of the T-E formulations, conversions of 99%, 98%, 98% and 94% were attained for the formulations with increasing concentration of photoinitiators, after 1200 s. This can be attributed to the rapid build-up of the crosslinked network in the highly viscous media of the HIPE, due to the high concentration of free radicals, hindering the propagation reactions, which results in a decrease in the photopolymerization rate [54,55]. A disadvantage of using high concentration of photoinitiators is the increase in the levels of yellowing.…”