ABSTRACT
The (stereoselective) living coordinative copolymerization of 1-alkenes with 4-aryl-1,6-heptadienes, in both the absence and presence of multiple equivalents of a reversible chain transfer agent, is established as a highly versatile strategy for production of multivariate hyperdimensional functionalized semi-crystalline or amorphous polyolefins that optionally possess either mono- or difunctionalized (telechelic) end-groups in combination with a programmable level of incorporation of orthogonal functional groups within the main-chain. The non-conjugated diene comonomers are readily obtained from a diverse range of aryl carboxaldehyde precursors through a one-step bis-allylation process. These results serve to provide a new platform for exploring the science and technology of a vast new landscape of functionalized classes of polyolefins that are now accessible in practical and scalable quantities.
ABSTRACT
A toolbox of living coordination polymerization methods based on CPAM group 4 metal initiators has been applied for the stereomodulation of poly(4-methyl-1-pentene) (PMP) tacticity to provide new fundamental forms in which thermal phase transitions, Tg and Tm , can be adjusted over a wide range. Also reported for the first time are the synthesis and properties of authenticated 1,2-regioregular atactic PMP, which serves to correct past errors regarding this fundamental polyolefin.
ABSTRACT
A general and versatile synthetic strategy for producing practical quantities of a wide range of phenyl-group-terminated hetero- and homotelechelic semicrystalline polyethenes and amorphous atactic and semicrystalline isotactic poly(α-olefins) is reported. The phenyl groups serve as synthons for functionalities of additional classes of telechelic polyolefins that can be "unmasked" through simple high yielding postpolymerization reactions. A demonstration of the value of these materials as building blocks for structural classes of polyolefin-based synthetic polymers was provided by syntheses of well-defined polyolefin-polyester di- and triblock copolymers that were shown to adopt microphase-segregated nanostructured mesophases in the condensed phase.
Subject(s)
Polyenes , Polymers , Alkenes , Polyesters/chemistry , Polymers/chemistryABSTRACT
We explore the growth mechanism of 3D Covalent Organic Frameworks (COFs) using imine-linked model systems. We confirm that 3D imine COFs crystalize through an amorphous polymer intermediate, whose conditional state is key for preferential generation of the ideal porous structure over the collapsed hydrated form.
