Interfacial Broadening Kinetics between a Network and a Linear Polymer and Their Composites Prepared by Melt Blending

Abstract

Nanomechanical mapping of interfacial broadening between an epoxy network and a linear poly­(methyl methacrylate) (PMMA) showed the generation of a new network resulting from transesterification reactions. The rate of interfacial broadening was found to decrease with annealing time and deviated significantly from that expected for a classical first-order transesterification reaction. The epoxy vitrimer/PMMA composites prepared by melt blending show a single-phase and homogeneous structure, quite different from thermoset and thermoplastic composites prepared by reaction-induced phase separation. The as-prepared composites have a dimensionally stable structure that does not decompose at elevated temperatures. Moreover, the stress relaxation of the composites slows with the vitrimer content and the stress does not relax even at extended times.

Nanomechanical mapping of soft materials with the atomic force microscope: methods, theory and applications

“…150 Spatially-resolved elastic modulus maps have explained the morphology and composition of multicomponent polymer systems made of dissimilar polymers. 151,152 An application at the interface in polymer science and biomedical devices involved the study of the swelling and degradation of biodegradable scaffolds. 153 Chemical and nanomechanical mapping of polymers was achieved by combining FV and with broadband infrared spectra.…”

Molecular Dynamics Simulation of the Structural, Mechanical, and Reprocessing Properties of Vitrimers Based on a Dynamic Covalent Polymer Network

“…Epoxy vitrimers can maintain a constant polymer cross-link density while exhibiting flow properties similar to those of silica when heated during material processing. Besides the earliest reported vitrimer polymers based on β-hydroxy esters, − a series of exchangeable chemical reactions have been developed for the preparation of materials with unique vitrimer properties, for example, disulfide exchange, − dioxaborolane metathesis, − imine exchange, , olefin translocation, transalkylation, transcarbonation, vinylogous urethane transamination, and siloxane silanol exchange reactions. , The reversible breakage and formation of dynamic covalent bonds can also be achieved in response to external stimuli, such as thermogenic response, , force response, pH response, and light response, and bring about some unique vitrimer behaviors, such as stress relaxation, , self-healing, ,,, shape memory, ,, 3D printing, recycling, ,, and degradation …”

Self-healing and polymer welding of soft and stiff epoxy thermosets via silanolates

“…Polymer welding typically requires methods like using solvents or heat for the interpenetration of linear polymers [68,69]. Therefore, welding has traditionally been mostly limited to thermoplastics, which can still be difficult with incompatible materials [29,30]. Here, by incorporating silanolate groups for dynamic bonding, different thermosets containing compatible chemistry for siloxane equilibration can be welded together.…”

“…But, in addition to sustainability, adaptable networks can also facilitate welding of thermosets through bond exchanges at the interface [26][27][28]. Although polymer welding is typically limited to suitable thermoplastics, incorporating compatible dynamic chemistry into different thermosets can enable strong bonding between the dissimilar materials [29,30]. In the case of welding soft and stiff materials together, the healing capability can help prevent delamination caused by disparate mechanical properties, allowing different thermoset materials to work together seamlessly.…”