Polymer Journal

Shibata, Mitsuhiro; Sugane, Kaito; Yanagisawa, Yuto

doi: 10.1038/s41428-018-0165-0pmid: N/A

Diallylated p-coumaric acid (A2CM) and triallylated caffeic acid (A3CF) were synthesized by the reactions of p-coumaric acid and caffeic acid with allyl bromide in the presence of potassium carbonate. The thiol-ene photopolymerization of A2CM and a pentaerythritol-based tetrathiol (S4P) as well as that of A3CF/S4P at allyl/thiol and (allyl + enone)/thiol ratios of 1/1 produced cured products. The FT-IR spectral analysis revealed that the thiol-ene reaction of allyl and thiol groups mainly progressed for the products cured at an allyl/thiol ratio of 1/1, while both allyl and enone groups reacted with thiol groups for the products cured at an (allyl + enone)/thiol ratio of 1/1. The progress of the thiol-ene reaction of the enone and thiol groups caused the lowering of the glass transition and 5% weight loss temperatures (T g and T d5). The A3CF/S4P cured at an allyl/thiol ratio of 1/1 exhibited the highest T g, T d5, tensile strength, and tensile modulus among all the cured products.

Wu, Xiaoxue; Zhao, Ziliang; Kang, Yu; Ji, Xiangling; Liu, Yonggang

doi: 10.1038/s41428-018-0162-3pmid: N/A

The viscoelasticity of poly(ethylene glycol) (PEG) in aqueous solutions with different concentrations of potassium sulfate (K2SO4) was studied by quartz crystal microbalance with dissipation (QCM-D), after coating a rigid supported lipid bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine on the silicon oxide substrate. The obtained viscoelastic properties of PEG in K2SO4 solutions agree well with the Zimm model predictions for linear polymer chains. With increasing K2SO4 concentration, the excluded volume exponent ν of PEG decreased from 0.565 in water to 0.55 in 0.19 mol/L K2SO4, and 0.50 in 0.43 mol/L K2SO4. The solvent quality gradually worsened for PEG with increasing K2SO4 concentration, which was verified by decreases in the polymer intrinsic viscosity and the corresponding Mark–Houwink exponent. The high-frequency characteristic of QCM-D makes it possible to directly study the viscoelasticity of polymer solutions in a low-viscosity solvent, which is complementary to conventional rheometers working at low frequency.

Sasaki, Takashi; Hiraki, Kazuaki; Athirah, Aizzahtul; Matsuta, Kodai; Takeuchi, Natsuki

doi: 10.1038/s41428-018-0163-2pmid: N/A

We investigated the possibility of detecting the interfacial glass transition of a polymer with static contact angle measurements of a liquid polyethylene glycol on the polymer surface. The observed contact angle θ reflects the deviation from an equilibrium state at low temperatures, and the temperature dependence of cos θ changes discontinuously at the interfacial glass transition temperature T g, manifesting a change in the interfacial entropy. This outcome was demonstrated experimentally for a liquid of polyethylene glycol (PEG) on an atactic polystyrene (PS) surface. The evaluated T g was ca. 362 K. This value is lower than a calorimetric T g for a bulk PS. This difference reflects molecular interactions at the interface, indicating that the T g obtained from the contact angle measurement is sensitive to the dynamics near the polymer/liquid interface.

Hara, Manami; Kitahata, Shigeru; Nishimori, Keisuke; Miyahara, Koki; Morita, Kenta; Tokuda, Kaya; Nishino, Takashi; Maruyama, Tatsuo

doi: 10.1038/s41428-018-0164-1pmid: N/A

Isotactic polypropylene (PP) is one of the most popular plastics. However, the remarkably low surface energy of PP prevents the surface functionalization of PP. We studied the surface functionalization of PP by dip-coating with a maleic anhydride-grafted chlorinated polypropylene (MPO)/methacrylate-based terpolymer mixture. A methacrylate-based terpolymer (PMFP) was synthesized, which contained perfluoroalkyl (R f )-conjugated monomers and poly(ethylene glycol)-conjugated monomers. Tape-peeling tests revealed that MPO successfully immobilized PMFP on a PP surface, although PMFP was less adhesive to PP. X-ray photoelectron spectroscopy (XPS), contact angle, and protein adsorption measurements revealed that the R f groups and PEG chains in PMFP were segregated to the outermost surface of the dip-coated layer. The surface segregation of these moieties produced a low-fouling surface on the PP substrate. In addition, we synthesized a terpolymer that contained R f groups and PEG chains with carboxy groups at their termini (PMFB) and used it to dip-coat a PP substrate. The surface segregation of side chains in PMFB induced the presentation of carboxy groups at the outermost surface, which were used as reactive sites for enzyme immobilization.

Nitta, Sachiko; Akagi, Miki; Iwamoto, Hiroyuki

doi: 10.1038/s41428-018-0161-4pmid: N/A

Porous hydrogels for the adsorption of metals from aqueous solutions were prepared from chitosan nanofibers (CNFs) and poly(ethylene glycol) diacrylate (PEGDA). These hydrogels exhibited high swelling rates and porosities, which were evaluated by a gravimetric method and scanning electron microscopy, respectively. Both factors were influenced by the CNF/PEGDA ratio. The prepared hydrogels adsorbed both transition metals (e.g., copper) and post-transition metals (e.g., tin). The adsorption capacity increased with increasing CNF/PEGDA ratio, indicating synergism between chelation and the enlarged surface area of the porous structure during adsorption. The kinetic data indicated that metal adsorption could be fit to a pseudo-second-order kinetic model, whereas the equilibrium data were fit to the Langmuir isotherm model. Overall, the results revealed that CNF-PEG hydrogels are promising adsorbent materials for metal recovery in environmental applications.

Ahmed, Kumkum; Kawakami, Masaru; Khosla, Ajit; Furukawa, Hidemitsu

doi: 10.1038/s41428-018-0166-zpmid: N/A

In this work, we present the preparation, characterization, and 3D printing of highly conductive, soft, and functional nanocomposite polymers. The prepared nanocomposite is a polymeric system that consists of poly (ionic liquid) (PIL), polymethylmethacrylate (PMMA), and multiwalled carbon nanotubes (MWCNTs) as fillers and an ionic liquid (IL) that acts as a plasticizer and dopant for the MWCNTs. The nanocomposites exhibited variable mechanical (strain at break: 50–250%) and conductive properties depending on their composition, and the highest conductivity of 520 Sm−1 was attained with 15 wt.% MWCNT loading owing to the well-defined morphology of the MWCNTs revealed by SEM. The thermal properties of the nanocomposites were measured by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The results revealed high thermal stability up to 340 °C regardless of the composition and a variable transition temperature dependent on the MWCNT, IL, and polymeric contents. Finally, the conditions for 3D printing were optimized, and as a proof of concept, we demonstrated the fabrication of a flexible, 3D-printed circuit, which can be bent and twisted without damaging the circuit.

Asai, Hanako; Okumura, Tomotaka; Sakamoto, Hiroaki; Nakane, Koji

doi: 10.1038/s41428-019-0186-3pmid: N/A

In the original published version of Table 1 and Table S1, the conductivity values are incorrect. The corrected Tables are as shown below.