Synthesis of Precision Poly(1,3-adamantylene alkylene)s via Acyclic Diene Metathesis Polycondensation

Abstract

Fully saturated, aliphatic polymers containing adamantane moieties evenly distributed along the polymer backbone are of great interest due to their exceptional thermal stability, yet more synthetic strategies toward these polymers would be desirable. Herein, we report for the first time the synthesis of poly(1,3-adamantylene alkylene)s based on α,ω-dienes containing bulky 1,3-adamantylene defects precisely located on every 11th, 17th, 19th, and 21st chain carbon via acyclic diene metathesis polycondensation. All saturated polymers revealed excellent thermal stabilities (452–456 °C) that were significantly higher compared to those of structurally similar polyolefins with aliphatic or aromatic ring systems in the backbone of polyethylene (PE). Their crystallinity increases successively from shorter to longer CH2 chains between the adamantane defects. The adamantanes were located in the PE crystals distorting the PE unit cell by the incorporation of the adamantane defect at the kinks of a terrace arrangement. Precise positioning of structural defects within the polymeric backbone provides various opportunities to customize material properties by “defect engineering” in soft polymeric materials.

Fast, Light-Responsive, Metal-Like Polymer Actuators Generating High Stresses at Low Strain

“…The well-dispersed azobenzene derivatives thus reside in non-crystalline amorphous regions, possibly anchoring the PE tails to the crystal faces, Article or in the (aligned) amorphous regions, not distorting the UHMWPE lattice (Figure S11) but simply conducting heat to the extended-chain PE matrix and generating large mechanical stresses. 37 The fact that no photo-induced stress is observed in water for either film supports the hypothesis that both C78 dopants act as photo-thermal agents (Figure S12). 4 The photo-thermal response of the azobenzene depends on the miscibility with the UHMWPE matrix, yet despite poor miscibility the short C12 side chain azobenzene still attained a photo-induced stress of $30 MPa (Figures S13A and S13B).…”

Controlling the crystal structure of precisely spaced polyethylene-like polyphosphoesters

“…Similarly, poly(1,3-adamantylene alkylene)s synthesized by ADMET polymerization also crystallized in an orthorhombic crystal structure. 23 Due to the rigid adamantane defect, the black-folding of the polymer chain at adjacent reentry sites of the crystal lamellae is sterically impossible. In contrast, our group previously investigated the crystallization behavior of two different polyphosphates bearing a methyl and a phenyl side chain.…”

Vitamin C Loaded Polyethylene: Synthesis and Properties of Precise Polyethylene with Vitamin C Defects via Acyclic Diene Metathesis Polycondensation

“…Precision polymers with pure aliphatic pendant groups placed every 20 CH 2 units along the chain show melting temperatures ranging from 63 °C for a methyl branch down to ∼12 °C for larger branches like propyl . For similar polymers containing in-chain aromatic or other bulky defects remarkably higher melting temperatures have been observed as well. − The vitamin C substituted polymer 6 is similar to the arylene ether polymer with the defect group substituted in the ortho-position reported by Song et al, which exhibited a melting temperature of 81.7 °C …”