Polar‐Functionalized, Crosslinkable, Self‐Healing, and Photoresponsive Polyolefins

Abstract

The nonpolar nature of polyolefins is one of their biggest limitations. Now, an efficient route to generate polar‐functionalized, crosslinkable, self‐healing, photoresponsive polyolefins with thermoplastic, elastomeric, and thermosetting properties is reported. Tunable amounts of carboxylic acid and a cyclic comonomer are installed onto polyolefins by palladium‐catalyzed terpolymerization reactions. The incorporated carboxylic acid unit can alter the surface properties of polyolefins. The subsequently introduced Fe3+/citric acid combination induces dynamic crosslinking and enables self‐healing. Under UV light irradiation, citric acid reduces Fe3+ to Fe2+ and decreases the crosslinking density. The Fe2+ moiety can be easily oxidized back to Fe3+, making the process reversible at the expense of citric acid. The incorporated cyclic comonomer modulates the crystallinity of polyolefins, provides elastic properties, and installs carbon–carbon double bonds for sulfur‐induced vulcanization.

Polystyrene Chain Growth Initiated from Dialkylzinc for Synthesis of Polyolefin-Polystyrene Block Copolymers

“…In this work, we pursued a more efficient method for PS chain growth from (polyolefinyl) 2 Zn with an additional aim to expand the scope of the chains that can be grown from (polyolefinyl) 2 Zn (Scheme 1). Recently, syntheses of functionalized POs are a topical issue [36][37][38].…”

Mechano-responsive hydrogen-bonding array of thermoplastic polyurethane elastomer captures both strength and self-healing

“…According to the Ashby plot of UTS versus self-healing temperature for recently reported elastomers, previous tensile strengths did not exceed 20 MPa without the aid of light or a temperature above 40 °C ( Supplementary Fig. 7 and Supplementary Table 3) 9, [21][22][23][24][34][35][36][37][38][39][40]42,43,47 .…”

“…However, the trade-off between mechanical and healing performance is the biggest hurdle that these materials face and need to overcome. The high chain rigidity, entanglement, and crystallinity required for mechanical strength con ict with the high diffusibility and exchange of dynamic bonds required for repairing damage [21][22][23][24] . Consequently, materials that autonomously heal at ambient temperature exhibit mechanical performance that is unsatisfactory for industrial commercialization.…”

Stereoselective Polymerization of an Aromatic Vinyl Monomer to Access Highly Syndiotactic Poly(vinyl alcohol)

“…To date copolymerizations of ethylene with a wide range of polar monomers have been achieved by protecting or separating the polar groups from contacting with the active species [ 8–10 ] or using late transition metal catalysts of tolerance to polar groups. [ 11–16 ] However, both the activity and the selectivity decrease obviously, and low molecular weight products containing a small amounts of polar monomer are always obtained. Regarding to homopolymerization of polar monomers, it is still a research topic far from success, although recent reports demonstrate that polar groups, in some cases, do not poison but activate the catalysts to afford high molecular weight and highly regular homo‐ or copolymers.…”