Effect of Benzoyl Peroxide Content on Physical and Mechanical Properties of a Two-Component Methylmethacrylate-based Traffic Paint

Hypothesis: A two-component methylmethacrylate (MMA) traffic paint, used in cold plastic road marking, is considered as a vital part of the safety infrastructure of the road networks and a tool for delineation and traffic control. This system must be well-maintained during its service life. The aim of this study was to evaluate the effect of benzoyl peroxide (BPO) curing agent content on the physical and mechanical properties of MMA traffic paints.
In order to optimize the amount of BPO, samples of two-component traffic paint were prepared and cured with 0.4, 0.8, 1.0, 1.2, 1.4, 1.6 and 2.0 wt% BPO. Different physical and mechanical properties of the samples, such as traffic no pick-up time, hardness, resistance against accelerated weathering conditions were evaluated and their mechanical properties were assessed using stress-strain analysis (SSA) and dynamic mechanical thermal analysis (DMTA).
Findings: The results showed that the amount of BPO was a critical parameter in physical mechanical performance of the paints, in such a way that the low and high levels of curing agent (0.4 wt% and 2.0 wt%, respectively) led to loss of paint properties. This could be related to insufficient curing agent (0.4 wt%) and its overdose (2.0 wt%) in the polymerization of methylmethacrylate. Increasing the curing agent to its optimal amount did not increase the polymer network density, and in some cases impaired the mechanical properties of the samples. The results also showed that the increase in peroxide content reduced the drying time (no pick-up time). Within the optimal range of BPO content level at 1.2 and 1.6 wt%, we achieved traffic paints of two-component formulations with optimum physical and mechanical properties.