The nature of the exceptional impact of ultra‐low silica contents on the properties of cyanate ester resin‐based nano‐ and subnanocomposites

Abstract

Our study clarifies the nature of the exceptional impact of the ultra-low content of silica (SiO 2 ) units on the properties of the heterocyclic cyanate ester resin (CER) network matrix in the subnano-or nanocomposites. To this effect, we have performed a series of calculations of average distances between SiO 2 units and the interfacial area values in the composites as functions of the content and size of SiO 2 units. The estimates were made for the CER composites with SiO 2 and POSS additives, based on these calculations and the composites' previously measured structural characteristics. It was found that the aforementioned unusual effect was controlled by the constrained interfacial matrix dynamics in the composites. Thus, when (a) the SiO 2 content was 0.03-0.1 wt %, (b) SiO 2 units and the matrix network had covalent bonding, and (c) SiO 2 units had quasi-regular distribution in the amorphous matrix (as found for the subnanocomposites), we found that distances between SiO 2 units equaled 6 and 10 nm, that is, these distances were commensurable with the lengths of Kuhn segments in heterocyclic macromolecules.

Absolute local conformation of poly(methyl methacrylate) chains adsorbed on a quartz surface

“…Similarly, when a polymer film supported on a solid substrate is well annealed, an adsorbed layer is formed on the solid surface [28][29][30][31][32][33] . The dynamics of chains in the interfacial layer are markedly different from those of the corresponding bulk chains [34][35][36][37][38][39][40][41][42][43][44] . These characteristics of chains in the interfacial layer are universal for rubbery and glassy polymers [45][46][47][48][49] , as mentioned above, and are closely related to the mechanical properties of the polymer nanocomposites [50][51][52][53][54][55] .…”

High Temperature Composites From Renewable Resources: A Perspective on Current Technological Challenges for the Manufacturing of Non-Oil Based High Char Yield Matrices and Carbon Fibers

“…The major part of cyanate esters industrially produced are aromatic polymers with strong rigidity of their cured phase, so blending with other thermosets to improve their processability in the composite industry is needed (Nair et al, 2001;Kandelbauer, 2014). The literature reports the effect of different nanofillers on the cure of CE resin (Amirova et al, 2021), in particular the introduction of silica (Bershtein et al, 2021), POSS (Li et al, 2021) was widely investigated. Combination of carbon fibers and nanofillers for ablative purposes have been recently considered in the paper of Rao et al, 2021b, where the authors studied the effect of organo-FIGURE 7 | Impact strengths and flexural moduli of BA and BD resin (4,4′-bismaleimidodiphenylmethane (BDM) and renewable bis(5-allyloxy)-4-methoxy-2-methylphenyl) methane (ABE) from bio-based lignin derivative as a function of allyl to imide molar ratio (n) (A); Biobased thermosetting resins based on bismaleimide and allyl-etherified eugenol derivatives (B); T g and renewable carbon contents of BTP, BD and other eugenol derived BMI resins (C); TGA curves of cured AEG/BMI (EB) (allyl-etherified eugenol prepolymerized with 4,4′-bismaleimidodiphenylmethane, with allyl/maleimide unit ratios of 1/1, 1/2 and 1/3 (D) Reprinted with permission from (Neda et al 2014;Miao et al, 2019;Ge et al, 2017).…”

Effective local elastic moduli of a strongly disordered medium

“…The elastic properties of polymer nanocomposites attract considerable interest due to their unique properties and great potential as future materials [12][13][14][15]. It was established that polymer doping with nanoparticles even in small concentrations could lead to significant changes in the elasticity of the host material [16][17][18][19][20].…”