Optimal conditions for the use of polyrotaxane as a cross-linker in preparing elastomers with high toughnesses, mechanical, and UV-resistance properties

Optimal conditions for the use of polyrotaxane as a cross-linker in preparing elastomers with high toughnesses

Conceptual diagram of a polymer network using polyrotaxane as a cross-linking agent

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  • We have investigated the self-assembly kinetics of silica nanoparticles (SNPs) into the polymer-like structure by time-resolved small-angle X-ray scattering (SAXS). The analysis of the SAXS data with a kinetic model revealed that the SNPs undergo self-assembly in a process akin to the step-growth polymerization of bifunctional monomers. This study offers a facile strategy to construct polymer-like structures from isotropic spherical nanoparticles.

    • Tatsuki Oishi
    • Ayae Sugawara-Narutaki
    • Rintaro Takahashi
    Rapid CommunicationOpen Access
  • The relationships between the macroscopic mechanical properties and lamellar structures of polyamide 11 obtained from different heat treatments were investigated. From the tensile tests, the maximum stress and strain at necking increase with the heat treatment temperature. WAXS measurements indicated that different crystalline phases formed depending on the heat treatment conditions. SAXS revealed that the lamellar thickness and long period increased with the heat treatment temperature. Based on these results, we elucidated that the macroscopic mechanical properties correlate with the lamellar thickness and long period.

    • Toyoshi Yoshida
    • Mei Touji
    • Yoshihisa Kaneko
    Original Article
  • We explored the feasibility of Tetra-PEG gel, a controllable hydrogel, as a new biomaterial to develop a coating agent for post-ESD ulcers. We examined the optimal conditions for hydrogel application and developed a specialized catheter, then investigated its properties. Ultimately, we successfully used the optimized hydrogel and device to cover post-ESD ulcers in the porcine stomach. Further optimization of the hydrogel and ongoing research through animal experiments are expected to deepen our understanding of the material’s effects on ulcer healing and contribute to its clinical applications.

    • Rina Cho
    • Hiroyuki Kamata
    • Mitsuhiro Fujishiro
    Original ArticleOpen Access
  • Triptycene-containing polymers featuring a rigid propeller-shaped structure have attracted attention for a wide range of potential applications including guest recognition, material transports, separations, catalysis, and organic electronics. Herein, with a thorough literature survey, we present the synthesis of the various types of triptycenes that provide components for functional polymers. We particularly focus on triptycene-containing polymers and two-dimensional assemblies based on the space-filling design that uses nested packing. Future perspectives on the functionalities brought about by the design of triptycene-containing polymers and molecular assemblies are also discussed.

    • Fumitaka Ishiwari
    • Yoshiaki Shoji
    • Takanori Fukushima
    ReviewOpen Access
  • The effects of an organic monoglyceride (OMG) plasticizer on the crystallization of the PLLA/PDLA (50/50) blend were investigated by examining the isothermal crystallization of the blend with different contents of OMG (1–5 wt%) using POM, DSC, and time-resolved WAXD. It was found that the increase of the OMG content promoted the exclusive formation of stereocomplex crystallites and enhanced its crystallinity while suppressing the formation of homocrystals.

    • Neimatallah Hosni Mohammed Mahmoud
    • Hideaki Takagi
    • Shinichi Sakurai
    Original Article
  • The thiol-Michael polyaddition of three dialkynyl monomers with several dithiols proceeded using triethylamine as the catalyst to give unsaturated poly(ester-thioether)s with the expected structures (Mn, 2.4 × 103 to 22.6 × 103; molecular dispersity index [Mw/Mn], 1.26–2.00). All of the poly(ester-thioester)s had single glass-transition temperature values between −27 and 49 °C. While the rigid main chains improved the glass transition temperature, all of the poly(ester-thioester)s showed apparent enzymatic hydrolysis by lipase but low biodegradability in biodegradation tests using activated sludge.

    • Katsuhisa Yano
    • Akinori Takasu
    • Hiroshi Eguchi
    Original ArticleOpen Access
  • The Suzuki–Miyaura coupling reaction of BrC6H4-SiRR’-C6H4Br 1 with phenylboronic acid 3 in the presence of tBu3PPd precatalyst 4 and CsF/18-crown-6 produced a phenyl-disubstituted product, indicating that the Pd catalyst underwent catalyst transfer on the silylene group. The polycondensation of 1 and phenylenediboronic acid 2 yielded cyclic polymers even when excess 1 was used. The obtained cyclic polymers containing the silylene group showed stronger fluorescence in solution than did the methylene counterpart.

    • Natsumi Harada
    • Rina Yachida
    • Tsutomu Yokozawa
    Note
  • Three cyclic oxoester-thioester hybrid monomers were studied for anionic and cationic ring-opening polymerizations. Anionic polymerizations using thiol with 2,6-lutidine were successful for the chemoselective cleavage of the thioester with the thiol propagating end, exhibiting the living character to some extent. The polymerization in 2,6-lutidine without an initiator produced macrocyclic polymers. The cationic polymerizations occurred with the aid of CF3SO3H and benzyl alcohol but involved side reactions with low chemoselective ring cleavage. The thioester unit caused the polymers to exhibit a lower Tg with greater thermal and photo degradability.

    • Mao Hirata
    • Tomoki Yoshimatsu
    • Masato Suzuki
    Original ArticleOpen Access