An outstanding tough, highly elastic, biodegradable, and thermostable hyperbranched epoxy was synthesized by a simple polycondensation reaction between a castor oil-based hyperbranched polyester polyol (HBPP) of monoglyceride of oil and bis(hydroxy methyl)propionic acid (Bis-MPA) and in situ-generated diglycidal ether of bisphenol A (DGEBA). The structure of HBPP was confirmed from FTIR, NMR, and different analytical studies. The formation of hyperbranched epoxy along with its structure was analyzed by different spectroscopic and analytical techniques. The poly(amido amine)-cured hyperbranched epoxy exhibited high tensile strength (42 MPa), extensibility (88% elongation), toughness (3144), scratch hardness (>10.0 kg), impact resistance (>100 cm), flexibility (bent up to 180°without damage), and biodegradation. The results indicate the strong influence of the amount of polyester polyol and bisphenol A on the performance of the thermosets. The study showed the superiority of the studied hyperbranched epoxy over the standard commercial bisphenol A-based epoxy (SBE) as well as the physically modified SBE with 10 wt % of HBPP. This biodegradable, elastic, and tough epoxy thermoset can be used as a sustainable advanced material.
A luminescent transparent hyperbranched epoxy nanocomposite with previously unachieved outstanding toughness and elasticity has been created by incorporation of a very small amount of carbon oxide nanodots. The nanocomposites of the hyperbranched epoxy with carbon oxide dots at different dose levels (0.1, 0.5, and 1.0 wt %) have been prepared by an ex situ solution technique followed by curing with poly(amido-amine) at 100 °C. Different characterizations and evaluations of mechanical and optical properties of the nanocomposites have been performed. The toughness (area under the stress-strain curve) of the pristine system has been improved dramatically by 750% with only 0.5 wt % carbon oxide dots. The tensile strength has been enhanced from 38 to 46 MPa, whereas the elongation at break improved noticeably from 15 to 45%. Excellent adhesive strength combined with transparency and photoluminescent behavior renders these materials highly interesting as functional films in optical devices like light-emitting diodes and UV light detection systems as well as in anticounterfeiting applications.
The present review article highlights the preparation, characterization, properties, and photochemical and electrochemical applications of carbon dot–metal based nanohybrids.
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