Synthesis and shape memory behavior of hyperbranched polyimides from thiol-ene click reaction

Stimuli Responsive Shape Memory Microarchitectures

“…[ 31 ] Further, the facile click chemistry used to access this particular functionality can also be used to install a variety of functional groups that can alter properties such as wettability without requiring purification or adversely affecting two –photon polymerization. [ 19,32 ] The shape memory resist compositions can also be tuned to achieve desired mechanical properties. In this case, the monomer benzyl methacrylate was incorporated to enable large deformations, and the chain building component has high cohesive energy density, which results in a substantial strain‐to‐failure.…”

Crosslinked porous polyimides: structure, properties and applications

“…However, in contrast to this behaviour, Wang et al 81 found that a change in anhydride linker from benzene L3 to naphthalene L4 (an increase in carbon percentage as well as conjugation) in their non-conjugated pPIs resulted in a drop in the T deg . Lu et al 24 also showed how increased thiol linkages in pPIs (present from linker N2) can result in increased T deg and increased char yields. Finally, Wu et al 82 found, counterintuitively, a decrease in T deg with increasing crosslinking percentage (and hence increased carboncarbon bond formation), with no further explanation provided.…”

“…The majority of crosslinked pPIs do not demonstrate melts or glass transitions (T g ). However, Lu et al 24 showed how control over the length of thiol linkages (N2) in pPIs allow manipulation of the T g , with a maximum of 59 °C appearing for moieties with 9 thiol linkers per linker unit. It is worth nothing that although this polymer is classified here as a pPI, the thiols are used for the formation of the final crosslinked product from the preformed diimide M2.…”

“…The formed diimide, functionalised with dicarboxylic acids, was then condensed with the tetraamine monomers C5 and C6 to produce benzimidazole linked pPIs. Lu et al 24 and Zhu et al 25 condensed maleic anhydride with the appropriate diamine linker to yield the preformed monomer diimides M4-6. Lu et al 24 then used diimide M4 and crosslinkers N1 and N2 to generate pPIs via click reactions.…”

“…Lu et al 24 and Zhu et al 25 condensed maleic anhydride with the appropriate diamine linker to yield the preformed monomer diimides M4-6. Lu et al 24 then used diimide M4 and crosslinkers N1 and N2 to generate pPIs via click reactions. Finally, Zhu et al 25 used preformed diimides M4-6 to generate pPIs via homo-thermal coupling.…”