TITLE:
Synthesis and Properties of Organic-Inorganic Hybrid Porous Polymers Obtained with Click Addition Reactions of Thiol-Functionalized Random Type Silsesquioxane by and Diacrylate or Diisocyanate Compounds
AUTHORS:
Tomoharu Miyanaga, Naofumi Naga
KEYWORDS:
Silsesquioxane, Thiol, Diacrylate, Diisocyanate, Gel, Porous Polymer, Morphology
JOURNAL NAME:
Open Journal of Polymer Chemistry,
Vol.10 No.1,
February
19,
2020
ABSTRACT: Organic-inorganic hybrid network polymers have been synthesized by
addition reaction of a thiol-functionalized random type silsesquioxane (SQ109)
and alkyl diacrylate or diisocyanate compounds. Thiol-ene reaction of SQ109 and
1,4-butanediol diacrylate (BDA) successfully yield porous polymer in toluene
initiated by azobis(isobutyronitrile) (AIBN) at 60°C.
Morphology of the porous polymers was composed by connected globules, and the
diameter of the globules decreased with increasing in the monomer concentration of the reaction system. By contrast, the reaction with 1,6-hexanediol diacrylate or 1,5-hexadiene yielded homogeneous clear gels.
Thermal analyses of SQ109-BDA porous polymers indicated that thermal
degradation of ester groups of BDA in the polymer network occurred at around
300°C. The porous polymer was also obtained by the reaction using a photo-initiator
(Irugacure184) at room temperature, and showed higher Young’s modulus than the
corresponding porous polymer obtained with the reaction with AIBN due to the
small size of the globules. Young’s modulus
of SQ109-BDA porous polymer increased with increasing in the monomer concentration of the
reaction systems. Thiolisocyanate addition reactions between SQ109 and hexamethylene diisocyanate (HDI) or
methylenediphenyl 4,4’-diisocyanate (MDI) were investigated to obtain network
polymers. The reactions in toluene yielded the corresponding homogeneous clear
gels. By contrast the reactions in a mixed solvent of toluene (50 vol.%) and N,N-dimethylformamide (50 vol.%)
produced porous polymers. The morphology of the porous polymers was composed by
connected globules or aggregated particles. The
size of globules and particles in the SQ109-HDI porous polymers was
larger than those in
the SQ109-MDI porous polymers. Thermal degradation of SQ109-HDI and SQ109-MDI
porous polymers started at round 260°C and showed endothermic peak at around 350°C derived from degradation of thio-urethane bond.