As a kind of high-performance thermoplastic crystalline resin, poly(4-methyl-1-pentene) (PMP) is characterized by its low density, low dielectric constant, exceptional mechanical and chemical properties, high transparency, and gas permeability. PMP has recently received more attention since COVID-19, because it is used as a hollow-fiber membrane for extracorporeal membrane oxygenation (ECMO) based on its high permeability and excellent biocompatibility. This review summarizes the chemical structure, synthesis, properties, and application of PMP. The advancements in catalyst systems for the catalytic synthesis of PMP, including Ziegler–Natta, metallocene, post-metallocene, and late-transition metal catalysts are emphasized. Furthermore, the molecular chain structure, helical conformation, and crystallization morphology of PMP, as well as its properties and applications, are also introduced in detail. Additionally, PMP composites and functional PMP materials are also described as promising and high-performance materials.

Late transition metal catalysts represent a significant class of olefin polymerization catalysts that have played an essential role in advancing the polyolefin industry owing to their highly tunable ligands and low oxophilicity. A key feature for the design of late transition metal catalysts lies in the steric bulk of the o-aryl substituents. Bulky 8-arylnaphthylamines have emerged as a promising aniline candidate for conducting high-performance catalysts by introducing axially steric hindrance around the metal center. This review focuses on late transition metal (Ni, Pd, Fe) catalysts derived from 8-arylnaphthylamines, surveying their synthesis, structural features, and catalytic applications in olefin (co)polymerizations. Additionally, the relationship between catalyst structure and catalytic performance is discussed, highlighting how these unique ligand systems influence polymerization activity, molecular weight, and polymer branching.

The development of earth-abundant nickel-based catalysts is currently one of the greatest challenges for the straightforward synthesis of functionalized polyolefins. With environmental protection concerns, controllable copolymerizations of ethylene with biosourced comonomers derived from castor oil, such as methyl 10-undecenoate (U-COOMe), 10-undecen-1-ol (U-OH), or 10-undecenyl bromide (U-Br), were realized using α-diimine nickel catalyst (Ni-DBB) with dibenzobarrelene backbone. Catalyst Ni-DBB was highly tolerant toward polar comonomers, and functional polyethylenes were successfully prepared. The influences of the polar group, temperature, and comonomer concentration were studied in detail. Catalyst Ni-DBB was able to catalyze the copolymerization of ethylene with U-OH to afford high-molecular-weight (~180 kg/mol) functional polyethylene in a controlled fashion. NMR analysis showed that the produced functional polyethylenes were highly branched and had broad melting peaks ranging from 0 to 30 °C. Water contact angle (WCA) measurements showed that the surface of the obtained hydroxyl-functionalized polyethylene changed from hydrophobic to hydrophilic with the introduction of the comonomer U-OH.

Late transition metal olefin polymerization catalysts have received more attention in the field of catalytic olefin polymerization. Barrelene-based α-diimine nickel and palladium olefin polymerization catalysts are rising stars because of their backbone structure and catalytic properties. In this review, we present a comprehensive review of barrelene-derived α-diimine nickel and palladium olefin polymerization catalysts. α-Diimine nickel and palladium catalysts are introduced from two aspects: barrelene-derived backbone and aniline derivatives with different substituents. The relationship between catalyst structure and catalytic properties is also emphasized. This review attempts to provide an inspiration for the design of high-performance barrelene-based catalysts.

Although hypercrosslinked porous polymers as highly efficient adsorbents can remove pollutants, hypercrosslinked polymers (HCPs) themselves are also a source of white plastic pollution. Development of degradable HCPs is highly desirable based on the full environmental protection concept. In this paper, we reported the direct synthesis of hypercrosslinked polyketones (HCPK-X, X = H, O ^t Bu) generated from degradable aromatic polyketones via external crosslinking technique. The hypercrosslinked structure of HCPK-X was fully characterized, and HCPK-O ^t Bu had a mesopores structure (1.27–68.5 nm) and large surface area ( S _BET = 321 m ² /g). HCPK-O ^t Bu exhibits a good adsorption capability for aniline removal from aqueous solution, and its enhanced adsorption capability is ascribed to the interactions between aniline and the carbonyl and tert -butoxy groups. The photodegradation of hypercrosslinked polyketones was evaluated and emphasized. The prepared hypercrosslinked polyketones can rapidly and efficiently decompose under UV light irradiation, which represents the first sample of degradable hypercrosslinked polymers.