Low‐frequency dynamic mechanical behavior of polyacrylate networks

Abstract

AbstractA low‐frequency vibration apparatus was used for measurements of the dynamic mechanical behavior of poly (methyl acrylate), poly (ethyl acrylate), and poly(octyl acrylate) networks in the frequency range of 0.001 to 0.5 Hz, and with temperatures from –40 to 100°C. The polymers were prepared by radical polymerization in the absence of crosslinking agent, and in the presence of 0.1 and 0.2 × 10−4 mole cm−3 ethylene dimethacrylate. The complex dynamic compliance values were determined in the rubber‐like region starting from log J'p = –7.5 and higher; the data obtained were reduced to a reference temperature of 25°C.The contribution of long retardation times of untrapped entanglements to the compliance in the rubber‐like region, according to Ferry (Je – JeN), was compared with the values obtained earlier for networks of poly (butyl methacrylate), poly (butyl acrylate), natural, butadiene‐styrene, and polybutadiene rubber. It was found that this contribution, at the same equilibrium compliance, is highest for rubbers, and higher for methacrylates compared to acrylates. The increasing length of side chains of polyacrylates leads to an increase in the difference (Je – JeN).