Hybrid Styryl-Based Polyhedral Oligomeric Silsesquioxane (Poss) Polymers

A Novel POSS-Based Copolymer Functionalized Graphene: An Effective Flame Retardant for Reducing the Flammability of Epoxy Resin

In this study, a novel copolymer, PbisDOPOMA-POSSMA-GMA (PDPG), containing methacryloisobutyl polyhedral oligomeric silsesquioxane (POSSMA), reactive glycidyl methacrylate (GMA), and bis-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide methacrylate (bisDOPOMA) and derivative functionalized graphene oxide (GO) were synthesized by a one-step grafting reaction to create a hybrid flame retardant (GO-MD-MP). GO-MD-MP was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Flame-retardant epoxy resin (EP) composites were prepared by adding various amounts of GO-MD-MP to the thermal-curing epoxy resin of diglycidyl ether of bisphenol A (DGEBA, trade name E-51). The thermal properties of the EP composites were remarkably enhanced by adding the GO-MD-MP, and the residue char of the epoxy resin also increased greatly. With the incorporation of 4 wt % GO-MD-MP, the limiting oxygen index (LOI) value was enhanced to 31.1% and the UL-94 V-0 rating was easily achieved. In addition, the mechanical strength of the epoxy resin was also improved.

Synthesis and thermal stability of hybrid polymers using UV photopolymerization based on polyhedral oligomeric silsesquioxanes

A series of hybrid polymers based on methacrylphenyl polyhedral oligomeric silsesquioxanes (MA-POSS) and methylmethacrylate (MMA) were rapidly synthesized via UV photopolymerization through a (2,4,6-trimethylbenzoyl)diphenylphosphine oxide-initiated reaction. The structure and morphology of hybrid polymers were characterized via Fourier transform infrared spectroscopy, proton nuclear magnetic spectroscopy, gel permeation chromatography, X-ray diffraction, transmission electron microscopy and scanning electron microscopy, which confirmed that the MA-POSS cage could be successfully incorporated into the polymethylmethacrylate (PMMA) chain. The obtained hybrid polymers had no obvious aggregation of MA-POSS. It can be concluded that MA-POSS were well-dispersed in the hybrid polymers. The thermal properties of PMMA–POSS hybrid polymers were investigated through differential scanning calorimetry and thermogravimetric analysis. Results show that the incorporation of POSS cage results in the enhancement of the glass transition temperature and the decomposition temperature of hybrid polymers as compared with PMMA polymers without MA-POSS.