Self‐Healing Ability of Poly(PEGMA‐5‐UPy) Evaluated by Thermomechanical Analysis

Abstract

The synthesis and characterization of polyethylene glycol monomethyl ether methacrylate (PEGMA) based copolymers incorporating three different percentages (2.5 wt%, 5.0 wt%, and 7.8 wt%) of urea-N-2-amino-4-hydroxy-6methylpyrimidine-N'-(hexametylen-n-carboxyethyl methacrylate) (HEMA-UPy) are reported. Nuclear magnetic resonance (NMR) and infrared spectroscopy (IR) confirm the synthesis procedure. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are employed to evaluate the thermal properties of the samples. DSC measurements evidence a slight increase in glass transition temperature (T g ), a consistent increase in crystallization and melting temperatures (T c and T m ), and a reduction in the crystallization degree (X c ) with increasing the amount of HEMA-UPy moiety. Dynamic mechanical analysis (DMA) is carried out at different values of temperature and oscillation frequency. It highlights the ability of the healed copolymer to recover the pristine values of storage modulus. The healing efficiency depends on the temperature history of the sample. For the sample healed at room temperature, the value of healing efficiency is 64%. DMA tests performed at higher temperatures, after some permanence at room temperature, evidence higher values in the healing efficiency. This demonstrates that the higher value of the temperature employed during DMA tests determines greater mobility of the chains causing an enhancement in the healing efficiency.

Surface Microphase Separation and Water-Induced Reconstruction of Fluorinated Amphiphilic Copolymer Coatings for Soil Release Fabrics

“…The glass transition temperature of F0, which corresponds to the homopolymer of MPEGMA, is measured to be −62.8 °C, while F100, which corresponds to the homopolymer of 13FMA, has a glass transition temperature of 33.2 °C. These values are consistent with the literature. ,, The DSC curves of all five polymers show only one glass transition region, indicating the successful synthesis of copolymers F25, F50, and F75 without obvious homopolymer formation (Figure a) …”

“…These values are consistent with the literature. 39,48,49 The DSC curves of all five polymers show only one glass transition region, indicating the successful synthesis of copolymers F25, F50, and F75 without obvious homopolymer formation (Figure 2a). The glass transition temperatures of F25, F50, and F75 are all located between the values of F0 and F100.…”

Inherent limitations of the hydrogen-bonding UPy motif as self-healing functionality for polymer electrolytes

“…16 Regarding polymer electrolyte engineering, the high bonding association constant and directional self-assembly of UPy render the polymer excellent mechanical properties that could otherwise only be achieved in covalently cross-linked polymers, whereas the reversibility at elevated operating temperature promotes the self-healing ability. 17–19…”

“…16 Regarding polymer electrolyte engineering, the high bonding association constant and directional self-assembly of UPy render the polymer excellent mechanical properties that could otherwise only be achieved in covalently cross-linked polymers, whereas the reversibility at elevated operating temperature promotes the self-healing ability. [17][18][19] Recent studies have proposed paradigms of polymer electrolytes utilizing UPy self-healing motifs to enable self-repairing properties and mechanical enhancement. 6,8,18,[20][21][22][23] Xue et al synthesized a highly stretchable and self-healing polymer electrolyte by tethering UPy motifs to a PEGMA polymer.…”

Verification of the Self-Healing Ability of PP-co-HUPy Copolymers in Epoxy Systems

“…In particular, an innovative method based on dynamic mechanical analysis (DMA) investigation has been proposed to obtain information about the healing efficiency of the Poly(PEGMA-5-UPy) copolymer at different values of temperatures and frequencies [ 50 ].…”