Structure–property relationships in acrylate/epoxy interpenetrating polymer networks: Effects of the reaction sequence and composition

Abstract

Interpenetrating polymer networks (IPNs) of poly(ethylene glycol) 200 diacrylate and diglycidyl ether of bisphenol A were formed over a range of compositions and with different reaction sequences. We controlled the reaction sequence by thermally initiating the cationic epoxy polymerization, photoinitiating the free-radical acrylate polymerization, and changing the processing order. The reaction was monitored by attenuated total reflectance Fourier transform infrared spectroscopy, photo differential scanning calorimetry. and modulated differential scanning calorimetry (mDSC). The glass-transition temperature was estimated from mDSC. Mechanical and rheological tests provided the strength and hardness of the materials. Morphology and phase separation were explored with optical and scanning electron microscopy. All of the physical properties were dependent on IPN composition. Some properties and the morphology were dependent on the reaction sequence. Significant differences in glass-transition temperature were observed at the same composition but with different reaction sequences. Even with minimal structure, correlations existed between the morphology and material properties with partially phase-separated samples exhibiting maximum damping. The rapid reaction allowed minimal phase separation, yet different reaction sequences resulted in significantly different properties. This systematic study indicated that the relationships between phase morphology, processing, and the physical properties of IPNs are complex and not predictable a priori.

Synthesis and gelation characteristics of photo-crosslinkable star Poly(ethylene oxide-co-lactide-glycolide acrylate) macromonomers

“…This increases the overall conversion, resulting in a higher storage modulus as shown in Figure 5. Nowers and collaborators observed a similar effect when acrylated poly(ethylene glycol) (PEG) was added to epoxy polymerization [42]. Reactions (6) and (7) are propagation reactions between a growing radical on the network with NVP monomer and SPELGA macromonomer, respectively.…”

Photochemical Production of Interpenetrating Polymer Networks; Simultaneous Initiation of Radical and Cationic Polymerization Reactions

“…Some kinetic studies on the photoinduced quasi-simultaneous IPN synthesis have been published [63][64][65]. Structure-property relationships in acrylate/epoxy IPNs have been investigated as a function of the reaction sequence and composition (the relationships between phase morphology, processing and physical properties of the IPNs are claimed as complex and not predictable a priori) [66].…”

Informatics for combinatorial materials science

“…13 In addition to composition, the reaction sequence and conditions have been demonstrated to affect reaction kinetics 14 and IPN properties and structure formation. 15,16 Thus, the structure-property relationships in IPNs are often complex and non-linear. To accelerate materials development, combinatorial methods have been widely used.…”