Carbon nanotube enhanced dynamic polymeric materials through macromolecular engineering

Abstract

Dynamic covalent Diels-Alder chemistry was combined with multiwalled carbon nanotube (CNT) reinforcement to make strong, tough and conductive dynamic materials. Unlike other approaches to functionalizing CNTs, this approach uses Diels-Alder...

Thermoresponsive, Recyclable, Conductive, and Healable Polymer Nanocomposites with Three Distinct Dynamic Bonds

“…Although equilibrium in this process favors formation of TM linkages (Figure 2), it is possible that one end of BMI cross-linker could undergo thiol-Michael addition with a thiol group on the polymer and the other end undergoes DA chemistry with MWCNT, ultimately resulting in effective reinforcement. 40 Unlike dual-dynamic materials, 7.5% crosslinked triply dynamic poly(EA 100 -UPyMA 2.5 -thiol 2.5 -FMA 2.5 ) showed that reinforcement can be achieved without necessarily losing extensibility (Figure 5d). Reinforced poly(EA 100 -UPyMA 2.5 -thiol 2.5 -FMA 2.5 ) had an average ε break of ∼2.20 mm/mm which is greater than all average ε break observed in Figure 5a−c (Table 1).…”

“…54−56 Additionally, DA reaction facilitates effective reinforcement between functional furan side chains in this study and MWCNT by formation of DA adduct between MWCNT and polymer chains. 37,40 Integration of multiple types of dynamic bonds in polymer materials to synergistically harness their unique properties is rare and not well understood, especially the integration of more than two different orthogonal dynamic exchanges. 57 Hence, DPNs proposed in this study show distinctive dynamic properties that can be attributed to the unique contributions of each dynamic exchange employed.…”

“…Therefore, our group earlier demonstrated an approach for fabricating bulk DPNs using multiwalled carbon nanotubes (MWCNTs) as nanoreinforcements in singly dynamic DA cross-linked polymeric materials. 40 We showed that well-engineered DPNs from DA bonds between pendant diene groups on polymer chains with π−σ bonds on the MWCNT surface acting as dienophiles can be achieved.…”

“…This is unlike most of the previously reported self-healing polymer nanocomposites that give increased strength with a trade-off in decreased elongation, which means the ability of a material to achieve a certain amount of strain. 40,45 ■ EXPERIMENTAL SECTION Synthesis of a Typical Dual-Dynamic Poly(EA-UPyMA-FMA) Material. Synthesis of Poly(EA 100 -UPyMA 3.75 -FMA 3.75 ).…”

Discrete oligourethanes of sequence-regulated properties – impact of stereocontrol

“…aGlass transition temperature calculated in deflection point of DSC curve (2 nd heating). 40,41 bMelting temperature calculated as a minimum from DSC curve (1 st heating).cDecomposition temperature at 5% weight loss read from TGA curve.dDegradation temperature determined at a maximum of the DTG curve.ePercentage weight of residues after degradation.…”