Volume 42 Issue 4, April 2010

Coupling polymerizations of 2,3-dibromo-N-substituted maleimide (DBrRMI) (R=benzyl (DBrBnMI), phenyl (N-phenyl-2,3-dibromomaleimide (DbrPhMI)), cyclohexyl (N-cyclohexyl-2,3-dibromomaleimide), n-hexyl (N-n-hexyl-2,3-dibromomaleimide) and n-dodecyl (N-n-Dodecyl-2,3-dibromomaleimide, DBrDMI)) were carried out using palladium or nickel catalysts. Number-average molecular weights (M_n) of poly(RMI-alt-Ph) or poly(RMI-alt-TP) obtained by Suzuki–Miyaura cross-coupling polymerizations of DBrRMI with benzene-1,4-boronic acid (PhDB) or 2,5-thiophene diboronic acid (TPDB) were 680–1270 by GPC analyses. In contrast, coupling polymerizations of DBrRMI with 1,4-diiodobenzene gave random poly(RMI-co-Ph). Poly(RMI-co-Ph)s exhibited higher thermal stability than monomer and poly(RMI-alt-Ph). Copolymers showed strong photoluminescence from yellow to light blue color in THF.

The surface-initiated graft polymerization of covalently bound polymer brushes attached to an sp³ random carbon network backbone structure is demonstrated. Poly(ethyl acrylate) (PEA), poly(4-fluorostyrene) (PFS) and poly(acrylonitrile) (PAN) brushes were grafted from the network backbone polymer poly(hydridocarbyne), 1, illustrating the breadth of reactivity of the network backbone. The grafted polymer brushes significantly change the solubility and surface characteristics of the poly(hydridocarbyne) sp³ random carbon network backbone.

Tuning the hydrophilic–hydrophobic balance of amphiphilic block-graft PCL-b-(PαN₃CL-g-PBA) copolymers by Click strategy.

A polysilsesquioxane having a bis(2–methoxyethyl)amide group and 15-crown-5-ether ring (MCPSQ) was newly prepared. In the behaviors of hydrophobic aggregation in the aqueous solution containing the chloride of alkali metals, the highest LCST was observed in the solution containing sodium ion as expected from the ring size of the crown ether. By the addition of sodium 4-phenylazobenzoate, the photochemical isomerization affected the aggregation behavior of MCPSQ.

Largely improved strength and abrasion resistance for styrene–butadiene rubber (SBR)/silica composites are demonstrated when sorbic acid (SA) is incorporated in the compounds. The abrupt changes in performance are attributed to the strong interactions between silica and SA and the largely improved dispersion of silica, which are realized by SA-intermediated linkages through grafting copolymerization and hydrogen-bonding mechanisms.

A new host material, PCNVTPA, was successfully synthesized for high-performance iridium complex light-emitting devices. Efficient energy transfer was observed from the host PCNVTPA to the guest Ir complex. Single-layer phosphorescent electroluminescent devices of ITO/PEDOT: PSS/PCNVTPA:Ir complexes/Ca:Al exhibited maximum luminance (2899cdm⁻²) and luminance efficiency (8.84 cd A⁻¹), respectively, which were much higher than those of PVTPA. Such an improvement was probably due to more efficient hole trapping in Ir complexes or better electron injection from the lower energy levels of PCNVTPA.

Fluorescent Fe(II) metallo-supramolecular polymers (Fe(II)-MEPEs) are synthesized through complexation of Fe(II) ions with new bisterpyridine ligands bearing triethylene glycol (TEG) chains at the ortho-position of pyridine rings. Although Fe(II) ion is known as a quencher of fluorescence, Fe(II)-MEPE containing TEG chains shows nearly a threefold higher retention of fluorescent properties compared with unsubstituted analogs.

Block copolymerization of cellulose and styrene was carried out by ATRP. Macroinitiators were prepared from three types of cellulose (DP=20, 50, 250). The resulting copolymers were characterized by ¹H NMR and SEC. The miscibility of the immiscible cellulose/PS blend was improved by the addition of block copolymer.