Interpenetrating Polymer Network of Rubbery Epoxy and Glassy PMMA: Network Inhomogeneities and Dynamic Heterogeneities

Abstract

Interpenetrating polymer networks (IPN) are model polymeric systems for vibration damping applications owing to their unique viscoelastic properties. They are characterized by presence of static frozen inhomogeneities at molecular scale and are dynamically heterogeneous at a segmental level. These fundamental and characteristic features of IPNs need to be characterized in order to deduce their structure–macroscopic property correlations. In the present study, we report sequential IPNs prepared from a polyether diamine cross-linked epoxy and triethylene glycol dimethacrylate (TEGDM) cross-linked poly­(methyl methacrylate) (PMMA). Positron annihilation lifetime spectroscopy (PALS) studies revealed a decrease in free volume hole sizes with increased PMMA content in the IPNs, implying interpenetration of polymer chains at a molecular level. Dynamic mechanical analysis measurements were carried out to get insight into the structural relaxations and viscoelastic properties of the IPNs. The IPNs exhibited dissipation factor (tan δ) values >0.3 over a broad temperature (∼10–120 °C) and frequency range (20–20000 Hz), which qualify them as efficient vibration dampers. Stress strain profiles of the IPNs evolved from an elastic to a glassy response with strain-hardening characteristics as the PMMA content was increased in the IPNs. Simultaneous strengthening, stiffening, and toughening of the epoxy matrix were observed with increased PMMA content in the networks. The IPNs were also characterized for liquid water and toluene sorption characteristics to obtain mechanistic insights into the transport properties of the synthesized IPNs. Increasing water uptake and decreasing toluene sorption characteristics were observed with increased PMMA content in the IPNs. The free volume size plausibly governs the water transport properties, while toluene sorption in the IPNs could be influenced by its thermodynamic interaction with the networks. In both cases, non-Fickian sorption kinetics was observed. We posit that the present studies and results provide the basis for designing and characterizing vibration damping networks for practical applications.

Imparting Reprocessability, Quadruple Shape Memory, Self-Healing, and Vibration Damping Characteristics to a Thermosetting Poly(urethane-urea)

“…From Figure a, an unusually broad tan δ peak encompassing a temperature range from −80 to 170 °C is observed, resembling the loss factor profiles of interpenetrating polymer networks (IPNs) . The broad tan δ profile of the networks is characterized by discernible peaks at −25 and 108–110 °C, with a broad interphase connecting the two segmental relaxation peaks.…”

“…From Figure 3a, an unusually broad tan δ peak encompassing a temperature range from −80 to 170 °C is observed, resembling the loss factor profiles of interpenetrating polymer networks (IPNs). 46 The broad tan δ profile of the networks is characterized by discernible peaks at −25 and 108−110 °C, with a broad interphase connecting the two segmental relaxation peaks. A continuum of relaxation times pertaining to the relaxation of HTPB, PPG, and polyol SS as well as extensively H-bonded HS domains could be the genesis of this broad tan δ peak.…”

Efficacious constrained layer damping of carbon black‐reinforced nitrile butadiene rubber‐polyvinyl chloride blend vulcanizates: A comprehensive study

“…19 However, most of the studies on VEMs reported in the literature pertain to their evaluation of loss factors from DMA. [20][21][22][23] Reports on their analysis at the system level (CLD or FLD) representing the real-time scenario of their application is rather scanty. [24][25][26] Prediction of vibration damping can be carried out using either closed-form solutions or the finite element method (FEM) with the aid of commercial software for numerical analysis.…”

Directly Using Paraffin as the Toughening Agent of Epoxy Composites: An Experimental and Molecular Dynamics Simulation Study

“…In past decades, various kinds of methods have been used to increase the toughness of the epoxy resin. A great deal of reports show that the introduction of soft phases such as elastomers, core–shell particles, block copolymers, and interpenetrating networks into the epoxy matrix can greatly improve the toughness. However, the incorporation of the soft phases will lead to the decrease of the glass transition temperature ( T g ) or mechanical properties such as strength, modulus, stiffness, and so on. , Besides, it was also demonstrated that the uniform distribution of rigid particles , in the epoxy matrix can overcome the disadvantages of using soft toughening agents by improving the toughness without sacrificing mechanical properties or T g .…”

“…1 In past decades, various kinds of methods have been used to increase the toughness of the epoxy resin. A great deal of reports show that the introduction of soft phases such as elastomers, 2 core−shell particles, 3 block copolymers, 4 and interpenetrating networks 5 into the epoxy matrix can greatly improve the toughness. However, the incorporation of the soft phases will lead to the decrease of the glass transition temperature (T g ) or mechanical properties such as strength, modulus, stiffness, and so on.…”