Research articles

We describe the synthesis of polycarbonate (PC) by means of the polycondensation of diol formate and dialkyl carbonate through an ester-carbonate exchange reaction. Furthermore, the polycondensation of diol formate and diethyl carbonate in the presence of polyester (PEs) under reduced pressure affords a statistical copolymer of PC and PEs. The composition of PC and PEs in the copolymer can be arbitrarily altered by changing the feed ratio of the monomers to PEs.

The effect of the nucleating agent masterbatch carrier resin on the nonisothermal crystallization of a pipe-grade polypropylene block copolymer was investigated at three different cooling rates using differential scanning calorimetry (DSC). Crystallization kinetic parameters obtained from DSC cooling curves showed that incorporation of a nucleating agent by means of a masterbatch increased the crystallization rate by approximately two times compared to that of the sample with the same concentration of nucleating agent without the use of a masterbatch.

A pair of the oppositely charged diblock copolymer was used to prepare the polyion complex (PIC) micelle by mixing them in an aqueous medium using electrostatic, hydrophobic, and π–π interactions. The PIC micelles attained the maximum size and aggregation number when the charges of the cationic and anionic blocks were neutralized. The PIC micelle was stable against NaCl because the core was formed by electrostatic, hydrophobic, and π–π interactions. The micelle can encapsulate charge and hydrophobic guest molecules.

We investigated stereospecific copolymerization of styrene with p-divinylbenzene (DVB) using an aryl-substituted [OSSO]-type zirconium(IV) precatalyst with dried modified-methylaluminoxane (dMMAO) as an activator. The resulting poly(iso-styrene‐co‐DVB)s possessed very high molecular weights (M_w = 93,000−131,000 g mol⁻¹) and unimodal polydispersity indices (PDI = 1.8−2.5). The DVB contents (7–20 mol %) in the copolymer could be varied depending upon the feed concentration. These copolymers exhibited an amorphous phase structure with glass transition temperatures (T_g values) of 84.8–110.9 °C.

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Organic compounds with conjugated carbonyl groups used as electrode material for secondary battery is attractive attention. We have been focused on disodium terephthalate and its polymer derivative as active anode material for secondary battery. Herein, we synthesized a novel vinyl polymer bearing an extended conjugated disodium dicarboxylate and it was evaluated as an anode active material for sodium-ion battery to discuss the correlation between structure and electrochemical properties. We suggest that the longer π-extended systems on the side chains provide a better anode performance of sodium-ion batteries.

Poly(substituted methylene)s possess higher dense side chains and their chain mobilities are restricted, relative to conventional vinyl polymers. The surface of poly(substituted methylene)s was more hydrophobic. In particular, the poly(substituted methylene) with perfluoroalkyl groups showed lower surface free energy than the corresponding vinyl polymer. Moreover, the surface of block-like copolymer of poly(substituted methylene) was more hydrophobic than that of random copolymer. The preparation methods of films of poly(substituted methylene) with ethyl ester side chains controlled their surface free energies and structures.

We demonstrate the preparation of composite vitrimer-like materials containing silica nanoparticles (SNPs), where the matrix is composed of polyacrylate-based polymers crosslinked via a pyridine–bromo quaternization reaction. The quaternized pyridine at the crosslinking point exchanges the bond pair via trans-N-alkylation at high temperatures. Thermal and mechanical investigations first reveal the formation of the bound rubber phase around the SNP, which eventually affects the relaxation behaviors at high temperatures. In the final section, some useful functions owing to the bond exchange nature, such as reprocessability and recyclability, are exhibited.

A side-chain crystalline block copolymer (SCCBC) was applied for the chemical modification of polyethylene surfaces. A block copolymer with stearyl and epoxy groups was prepared by nitroxide-mediated living radical polymerization. This copolymer had a phase transition temperature of ~40 °C. When the SCCBC was immobilized on polyethylene, a polymeric layer with nucleophilic reactivity was formed. The layer thickness increased with increasing copolymer concentration. Galactoside ligands were added to the polymeric layer by the ring-opening addition reaction of the epoxide. The glyco-functionalized interface exhibited specific protein binding.

The first main-chain type triphenylarsine (AsPh₃) polymers were synthesized by Suzuki-Miyaura polycondensation. The electronic and photophysical properties of the AsPh₃ polymers were comparison with model compounds by experimental and computational methods. As a result, it was found that the conjugated systems were expanded through the arsenic atoms. The present AsPh₃ polymers are promising as luminescent materials.

The direct characterization of various loops with different topologies within polymer networks remains a major challenge in the field of polymer and materials science. We propose a partially junction-cleavable network as a universal platform for directly probing various loops in polymer networks. Various loops are formed in the copolymerization of deliberately designed polyfunctional monomers with partially cleavable and uncleavable junctions. The network transforms to soluble oligomers through cleavage at the junctions, and partial loops are preserved. The preserved monoloops and spiro-biloops with various sizes are directly qualified by MALDI-TOF MS, which has never been achieved by any current methods.

In this work, POSS with an acetylacetonato group (POSS-acac) and metal–coordination polymers comprising POSS-acac (CP(Metal)s) were synthesized. The possible structure of CP(Metal)s was estimated from the UV–Vis spectrum and the residual mass after burning off and the surface morphologies of the CP(Metal)s were observed using scanning electron microscopy.

No new chemical compounds were found in the copolymer acrylamide – acrylonitrile – sodium 2-acrylamido-2-methylpropanesulfonate with the composition of [72]:[10]:[18] that was subjected to thermohydrolysis at temperatures up to 160 °C, with the exception of carboxyl groups in place of amides. Thermohydrolysis up to 200 °C causes partial degradation and changes in the acrylate copolymer. The intrinsic viscosity, molecular weight and average sizes of the solvated copolymer macromolecular coils were found to decrease with increasing hydrothermal treatment temperature.

The biobased, rigid, and fire-retardant monomer (BDBE) was synthesized and employed in furanic polyester (PECBFs) preparation. The T_g of PECBFs increased up to 95 °C when BDBE content reached 25%. In combustion test, the samples self-extinguished immediately when BDBE content are more than 15%. The obtained copolyesters were expected to be applicated in the fields of firefighting materials and electronics.

Controlled structural color visibility was achieved using colloidal particles covered with a catechol polymer shell layer. When exposed to ammonia vapor, the pellet sample obtained by assembling the particles extended the conjugated length of the shell polymer, giving the particles the ability to absorb scattered light in situ and improving the visibility of structural colors.

Silver(I) ions in nonpolar solvents were used to polymerize expanded l-lysine and l-ornithine derivatives. Introducing a bulky hydrophobic acyl group into the terminal amino group of the side chain increased the solubility of the amino acid in chloroform. Polymerization proceeded via the formation of head-to-head and tail-to-tail linkages, which resulted in chiral helical structures. Circular dichroism measurements and density functional theory calculations were used to estimate the overall secondary structures, which were significantly different from each other despite the small difference, namely, with or without the fourth CH₂ moiety.

The shear-induced crystallization behavior of the blends of cyclic polyethylene (C-PE) and linear polyethylene (L-PE) was investigated. This figure shows the formation rate of shish-like fibril crystals (I) in the blend systems of C-PE(230k)/L-PE(42k) and C-PE(230k)/L-PE(104k) against the weight fraction of L-PE, Φ_L-PE. I reached a maximum at a certain Φ_L-PE. As Φ_L-PE increased, that is, as the entanglement density increased, the formation of the oriented melt was promoted. Crystallization was also suppressed by the entanglements. The maximum value of I was observed owing to these two competing factors.

Synergistic effects of adding silica, as a secondary filler, to styrene-butadiene rubber composites highly filled with carbon black was investigated. It was shown that there is a critical concentration of silica at which improvements in the Payne effect, mechanical properties, abrasion resistance, and heat build-up were at extrema. This behavior was attributed to the filler networking in the hybrid filler systems, at which work of adhesion in a three-component system was considered as the driving force for flocculation of the primary filler and final morphology of fillers in hybrid composites.

Systematic trade-off relationship between increased stress and decreased strain range at soft elasticity with the addition of crosslinkers in liquid crystal elastomers (LCEs). Control of the crosslink density is within the range of already-established synthetic process adjustments. By selecting the molar ratio of the crosslinkers, the set of stress and strain range at soft elasticity can be fixed arbitrarily. By controlling the crosslink density of LCEs at different sites, multimodal actuators can be realized.

PLA-pectin biocomposites were prepared at pectin contents from 2 to 8% w/w. The mechanical properties of PLA-pectin were considerably improved after the annealing process, especially at 4% w/w of pectin according to being the best dispersion indicated by SEM and synchrotron-based FT-IR mapping. Moreover, pectin aids in the crystallization of PLA confirmed by in situ SR-WAXS. The crystallization rate and crystallinity were maximum at 8% w/w pectin addition. Finally, the pectin dispersion is the main factor in determining the mechanical and thermal properties of biocomposites.