Synthesis and properties of degradable gels and porous polymers including acetal group in the network structure by addit
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Synthesis and properties of degradable gels and porous polymers including acetal group in the network structure by addition reaction of multi‑functional phenols and divinyl ether compounds Naofumi Naga1,2 · Kazuma Hasegawa2 · Hassan Nageh3 · Tamaki Nakano3,4 Received: 30 June 2019 / Revised: 2 October 2019 / Accepted: 25 November 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract Gels containing acetal group have been synthesized by addition reaction of multifunctional phenols, 1,1,1-tris(4-hydroxyphenyl)ethane (THPE) or tannic acid (TA) and divinylethers, diethylene glycol divinyl ether (DEGVE) or polyethylene glycol divinyl ether (PEGVE) in tetrahydrofuran (THF) or 1,4-dioxane (DO) using pyridinium p-toluenesulfonate as a catalyst under nitrogen atmosphere. The gels synthesized from DEGVE showed higher Young’s modulus, breaking stress, and lower breaking strain than the gels synthesized from PEGVE. The gels in DO showed higher mechanical properties than those in THF due to the high affinity between the network structure and the solvent used. The gels with TA showed lower Young’s modulus than those with THPE derived from flexible molecular structure of TA. The reaction of THPE and PEGVE in acetonitrile induced phase separation, and yielded porous polymer formed by connected globules about 10 μm diameter. The dried porous polymers showed remarkable increase in the Young’s modulus in comparison with the corresponding gels in THF or DO. The gels and porous polymers were degraded under atmospheric conditions caused by hydrolytic degradation of acetal groups in the network structure. The present hydrolytic degradable materials would be applicable for drug carriers or sensors for humidity or water. Keywords Phenols · Divinyl ether · Acetal · Gel · Porous polymer · Network structure · Mechanical property
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s0028 9-019-03033-1) contains supplementary material, which is available to authorized users. * Naofumi Naga [email protected]‑it.ac.jp Extended author information available on the last page of the article
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Polymer Bulletin
Introduction Polymer materials with network structure are widely used such as elastomers, forms, gels, and coatings. Network structure in the polymers would enhance the mechanical properties and/or thermal stability of the polymers. Although the network polymers are usable materials, their disposal or recycle must be difficult. Biodegradable network polymers are one of the usable materials to resolve these issues [1, 2]. Various types of degradable network polymers with degradable units by external stimulations, such as, pH, redox, temperature, light, and mechanical force, have been developed [3–36]. The network polymers are normally synthesized by (co)polymerization of bifunctional monomers or crosslinking of liner pre-polymers using various chemical reactions. The network polymers also can be synthesized by addition reaction of multi-functional c
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