Application of calcium montmorillonite on flame resistance, thermal stability and interfacial adhesion in polystyrene nanocomposites

Abstract

To exploit the application of calcium montmorillonite (CaMt) and improve the flame resistance of polystyrene (PS), two kinds of long carbon chain quaternary ammonium bromides with different spatial effect (i.e., cetyltrimethyl ammonium bromide (CTAB) and didodecyl dimethyl ammonium bromide (DDAB)) were used to intercalate CaMt for yielding corresponding organic calcium montmorillonite (CaOMt). The PS nanocomposites containing CaOMt (PS/CaOMt) were prepared by melt blending method. The effects of CaOMt on flame resistance, thermal stability, tensile properties and interfacial adhesion of PS/CaOMt were investigated. The results showed that both CTAB and DDAB were intercalated into CaMt to get CaOMt with an exfoliated/intercalated structure, which could endue good interfacial adhesion and thermal stability for PS/CaOMt. All peak values of flame resistance parameters of PS/CaOMt decreased and corresponding combustion times were postponed obviously. Moreover, Young’s modulus of DDAB-intercalated PS/CaOMt was improved by 49.1% while its tensile strength kept at the same level as PS.

A Short Review on the Effect of Surfactants on the Mechanico-Thermal Properties of Polymer Nanocomposites

“…The modification of MMT improved the mechanical properties of the nanocomposites, such as tensile strength, Young's modulus, and elongation at break, by up to 32%, 30%, and 18%, respectively, compared to the unmodified MMT/PS nanocomposite. The increases were related to the exceptional dispersion of DDAB-modified MMTs in the PS matrix and the remarkable adhesion between the modified MMTs and the PS [32]. Moreover, the degradation temperature of the nanocomposites also increased by up to 7.1%, possibly because DDAB, with two long alkyl chains, could provide outstanding thermal stability [32].…”

“…The increases were related to the exceptional dispersion of DDAB-modified MMTs in the PS matrix and the remarkable adhesion between the modified MMTs and the PS [32]. Moreover, the degradation temperature of the nanocomposites also increased by up to 7.1%, possibly because DDAB, with two long alkyl chains, could provide outstanding thermal stability [32]. Table 8 clearly displays that the modification of inorganic and organic nanofillers by cationic surfactants has improved the mechanico-thermal properties of the prepared polymer nanocomposites, regardless of the type of the cationic surfactant.…”

“…On the other hand, DDAB could also modify inorganic nanofillers like MMT and modified MMTs have been applied for the preparation of MMT/PS nanocomposites [32]. The modification of MMT improved the mechanical properties of the nanocomposites, such as tensile strength, Young's modulus, and elongation at break, by up to 32%, 30%, and 18%, respectively, compared to the unmodified MMT/PS nanocomposite.…”

“…The application of bio-based nanofillers, for example, CNCs [15,18,28,29], CNPs [30], NCFs [8,19], and CNWs [7,16], also contribute to the production of nanocomposites because they are renewable and sustainable materials. Surfactants (examples are also displayed in Table 2), for instance, HTAB [13,20,31], DDAB [12,32], SDS [4,21], Ultraric PE 105 [19], Niax L-595 [8], HMAC [9], Triton X-100 [6,10,11,24], Beycostat A B09 [15,17,18,28], LAE [29], PEGMONO [14,16], Pluronic [7,14], OA [3], AK8805 [5], SA [2], PA [22], Span 60 [30], and BHHB [1], are commonly employed for modifying nanofillers in the preparation of polymer nanocomposites.…”

Green Highly Clay-Filled Polyethylene Composites as Coating Materials for Cable Industry—A New Application Route of Non-Organophilised Natural Montmorillonites in Polymeric Materials

“…Interestingly, natural MMTs deposits always consist of MMTs-Ca or MMT-Ca/MMT-Na mixtures (the latter mineral does not occur alone). Features of polystyrene filled with a MMT-Ca were analysed in [ 23 ], however, this raw clay was not tested in polyolefins. Considering the relatively positive influence of the clays on flammability limitation of a few thermoplastic polymers as well as the above-mentioned disadvantages of OMMTs, it seems to be interesting to investigate PE composites with a high content of MMTs-Ca.…”