Multifunctional layered double hydroxide (LDH) based epoxy nanocomposites

摘要

As one of the most important thermosetting polymers, epoxy resin (EP) has acquired wide application in the fields of coating, adhesive, electronic/electrical insulation, carbon fiber composites and etc. EP possesses many outstanding advantages, such as low shrinkage, high thermal and mechanical stabilities and excellent solvent and chemical resistance. However, like most of polymeric materials, high flammability ofEP is its main fatal drawback, which has severely restricted the application fields required a remarkable flame-retardant standards. Thus, the flame retardancy of epoxy resins continues to remain as a very important area of research for polymer chemists and material engineers. Such research is also highly encouraged by the polymer industries because of huge economic and sociological casualties involved each year in fire accidents. Among the various methods of improving flame retardancy of polymeric materials, incorporation of flame retardants is a very commonly used one.The present work and the relevant reporting involve the investigation of a relatively new fascinating nano-filler, known as layered double hydroxide (LDH) as potential flame retardant for polymers composites. The basic reason for selecting LDH or more specifically magnesium-aluminum based LDH (Mg-Al–LDH) is their typical metal hydroxide-like chemistry and conventional clay-like layered crystalline structure.The current dissertation containing:•Functionalization of LDH;Multi-modifiers’ systems composed by bio-based modifiers such as hydroxypropyl-sulfobutyl-beta-cyclodextrin sodium (sCD) and its hybridized form with chalcone species (fCD), taurine (T), phytic acid (Ph), and dodecylbenzenesulfonate (DBS) were fabricated in this thesis, each designed for specified feature, aiming at developing high performance fire retardant epoxy nanocomposites.•Preparation and characterization of functionalized LDH based epoxy nanocomposites;Based on these functionalized LDHs, bisphenol A epoxy resin and diamino diphenyl sulfone (DDS), and utilizing multi step mixing method followed by appropriate curing process, series functionalized LDH/Epoxy nanocomposites have been developed.•Structural Properties relationship;The structural morphology of LDH/epoxy nanocomposites was investigated by transmission electron microscopy (TEM) and wide-angle X-ray scattering (WAXS), revealing that multi-modified LDH based epoxy nanocomposites showed much better dispersion state than the epoxy composites containing un-modified LDH or single modifier modified LDH. In contrast to conventional LDHs based epoxy composites, the functionalized LDH based epoxy nanocomposites show significantly improvement on both flame retardancy, such as passing UL94 V0 rating and significant reduction of peak of heat release rate, total heat release, total smoke, etc. and well maintenance on impact, flexural, micro-mechanical and anti-UV properties. Such multifunctional nano-hybrid will provide a promising solution to develop various functional epoxy-based composites for advanced applications.