Structure, thermal, and mechanical properties of DDM‐hardened epoxy/benzoxazine hybrids: Effects of epoxy resin functionality and ETBN toughening

Abstract

Bifunctional, trifunctional, and tetrafunctional epoxy (EP) resins were hardened with stoichiometric amount of 4,4'-diaminodiphenyl methane in presence and absence of benzoxazine (BOX). The EP/BOX ratio of the hybrid systems was constant, viz. 50/50 wt %. For the bifunctional EP, the EP/BOX range covered the ratios 75/25 and 25/75 wt %, as well. Epoxy-terminated liquid nitrile rubber (ETBN) was incorporated in 10 wt % in the systems with trifunctional and tetrafunctional EP, and in 10, 15, and 20 wt % in the EP/BOX with bifunctional EP to improve their toughness. Information on the structure and morphology of the hybrid systems was received from differential scanning calorimetric, dynamic-mechanical thermal analysis, atomic force microscopic, and scanning electron microscopic studies. The flexural, fracture mechanical properties, thermal degradation, and fire resistance of the EP/BOX and EP/BOX/ETBN hybrids were determined. It was found that some homopolymerized BOX was built in the EP/BOX conetwork in form of nanoscale inclusions, whereas ETBN formed micron scaled droplets of sea-island structure. Incorporation of BOX improved the charring and fire resistance, enhanced the flexural modulus and strength, reduced the glass transition (T g ), the fracture toughness, and energy. Additional modification with ETBN decreased the charring, fire resistance, flexural modulus and strength, as well as T g, however, improved the fracture toughness and especially the fracture energy.

Investigation on Rubber-Modified Polybenzoxazine Composites for Lubricating Material Applications

“…For example, blending between benzoxazine resins and epoxy resins, polyurethanes, and dianhydrides (Ref [12][13][14][15][16] was considered to be a potentially effective measure to enhance thermal or mechanical properties as well as flammability of the polymers. Furthermore, thermosetting copolymers based on benzoxazine resins and rubbers such as amine-terminated acrylonitrile-butadiene (ATBN) and epoxyterminated liquid nitrile rubber (ETBN) have been reported to provide various useful characteristics ( Ref 17,18). As an example, the combination of N-alkyl benzoxazine resin with ATBN resulted in a significant enhancement of the fracture toughness properties of the polybenzoxazine.…”

“…Although previous studies have found that the liquid rubber can improve the toughness of the polybenzoxazine ( Ref 17,18), there is very little or no information about the effect of the liquid rubber on the rheology, cure kinetics, and tribological behaviors of the polymer for self-lubricating polymer composites. Therefore, in this work, those behaviors of outstanding liquid rubber-modified polybenzoxazine composites including liquid rubber-modified polybenzoxazine filled with a fiber base, a friction modifier, and filler will be investigated in order to design tribosystems and select materials based on the wear map.…”

Novel epoxy-benzoxazine water-based emulsions with reactive benzoxazine surfactants for coatings

“…line™ FP, Binder, Tuttlingen, Germany). The long residence time at 210°C, recommended also by group of Grishchuk [14,15,18], was selected based on FT-IR analysis to achieve complete curing of both epoxy and benzoxazine resins. Transparent brownish epoxy-polybenzoxazine thin films were obtained after curing.…”

“…Unfortunately, also copolymerization of benzoxazines with epoxy resins takes place at elevated temperatures [8,[10][11][12][13][14][15][16][17][18]. However, combining epoxy and benzoxazine resins seems a very perspective approach to design thermosets of enhanced properties, since also epoxy resins possess some excellent properties, such as good chemical resistance to solvents and good adhesion to many substrates [8,11,18,19]. One of promising applications may be an epoxy-benzoxazine coating for different substrates.…”

Halogen-free phosphorus-containing flameretardant epoxy composites

“…The representatives of ammonia-based FRs (Grishchuk, Sorochynska et al et al 2013) are the ammonia-compounds guanidine (Jin, Xia et al et al 2014), urea, APP (Nie, Hu et al et al 2008, Wang, Liu et al et al 2009, Schartel, Weiß et al et al 2010, Liu, Zhang et al et al 2011, Lim, Mariatti et al et al 2012, Tang, Wang et al et al 2013, Qu, Wu et al et al 2014, Wang, Zhang et al et al 2014, Qin, Li et al et al 2015, Tan, Shao et al et al 2016, Matykiewicz, Przybyszewski et al et al 2017, ammonium pentaborate (Alongi andMalucelli et al 2012, Shen et al 2014) and ammonium sulfamate (Dahiya, Kandola et al et al 2013, Coquelle, Duquesne et al et al 2014, Tang, Zhang et al et al 2016. In particular, APP is the most common N-FR used as a single composition FR or as part of intumescent FRs in thermoplastics, thermosets, foams and coatings.…”