Synthesis of joint-linker type gels and porous polymers by addition reactions of multi-functional thiol and alkyl diacrylate, diisocyanate compounds

Joint-linker type gels and porous polymers have been synthesized by addition reaction of multi-functional thiol and alkyl diacrylate or diisocyanate compounds. The reaction of multi-functional thiol, 1,3,5-tris(3-mercaptobutyloxethyl)-1,3,5-triazine-2,4,6- (1H,3H,5H)-trione (3T) or pentaerythritol tetrakis(3-mercaptobutylate) (PTMB), as joint molecule, and alkyl diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, as linker molecule in toluene successfully yield the corresponding gels. Network structure of the gels was quantitatively characterized by means of a scanning microscopic light scattering. The obtained gels formed homogeneous network structure with 1.2–2.0 nm of mesh. Mechanical properties of the gels were investigated by compression test. Increasing of the monomer concentration increased Young's modulus and breaking stress of the gels. The gels composed of PTMB showed high Young's modulus and breaking stress than the gels composed of 3T. The gels were also prepared in propylene carbonate or dimethyl sulfoxide (DMSO), and the gels prepared in DMSO showed high Young's modulus. The addition reaction of 3T or PTMB and diisocyanate compound, hexamethylene diisocyanate (HDI) or 1,12-diisocyanatododecane (DDI), in toluene yielded porous polymers induced by phase separation during the polymerization. The porous structure was formed by connected globules about 5–10 μm diameter. The reactions of 3T, PTMB with HDI, DDI in tetrahydrofuran (THF) or N,N’-dimethylformamide (DMF) yielded transparent gels, and the gels prepared in DMF showed higher Young's modulus than those prepared in THF.