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In this contribution, we reported the synthesis of a novel trifunctional POSS cyclic carbonate [POSS-3(5CC)]. With a difunctional five-member cyclic carbonate and a trifunctional polyetheramine as the precursor, the nanocomposites of polyhydroxyurethane (PHU) with POSS were synthesized. Transmission electron microscopy (TEM) showed that the nanocomposites of PHUs with POSS were microphase-separated; the spherical POSS microdomains via POSS-POSS interactions were generated with the size of 20~40 nm in diameter. After the introduction of POSS microdomains, the nanocomposites displayed improved thermal and mechanical properties. More importantly, the nanocomposites still displayed the reprocessing properties of vitrimers.

Both difunctional five-membered cyclic carbonate (E5CC) and trithiocarbonate (E5CTC) were synthesized via the reactions of diglycidyl ether of bisphenol A (DGEBA) with carbon dioxide (CO 2 ) and carbon disulfide (CS 2 ), respectively. These two monomers were employed to synthesize linear poly(hydroxyurethaneco-mecaptotrithiourethane) [P(HU-co-MTU)] copolymers via the polymerization with an α,ω-diamino-terminated poly(propylene oxide). By controlling the mole ratios of E5CC to E5CTC, the P(HU-co-MTU) copolymers were synthesized with variable contents of thiol groups. It was found that the linear P(HU-co-MTU) copolymers were readily cross-linked with the disulfide bonds which were in situ generated via the radical coupling of the side thiol groups. The cross-linking exerted a profound impact on the thermomechanical properties of the materials. The glass transition temperature (T g 's), Young's moduli and tensile strengths were significantly enhanced with increasing the contents of disulfide bonds. More importantly, the networks significantly displayed the self-healing and reprocessing properties, which are attributable to the dynamic exchanges of disulfide bonds.

In this contribution, we reported a novel approach to crosslink the linear poly(n-butyl acrylate)-POSS copolymers via dynamic urea exchange reaction. First, the linear copolymers of n-butyl acrylate, POSS acrylate with...