Prominent Crystallization Promotion Effect of Montmorillonite on PTT/PC Blends with PTT as the Continuous Phase

Abstract

To regulate the crystallization of poly(trimethylene terephthalate) (PTT) retarded by melt blending with polycarbonate (PC), the crystallization of the PTT/PC blend was investigated employing nano-montmorillonite (MMT) as a crystallization promoter with PTT as the continuous phase. The results showed that MMT exhibits a significant promoting effect on PTT crystallization; the presence of 1 wt. % MMT shifts the initial and peak crystallization temperatures of the 70/30 PTT/PC blend to ~17 °C and ~32 °C, respectively. Additionally, the full width at half maximum (FWHM) narrows by ~45%, and the ΔHc increases by 3.7 J.g−1. The accelerating effect of MMT is determined by its distribution and dispersion which depends on the shear intensity, mixing mode, and loading. MMT is easier to exfoliate via the two-step method than by the one-step method. The distribution in the PTT phase is enriched along the phase interface forming an MMT layer. This endows sections of the PTT with abundant nuclei and thus crystallization is promoted markedly compared with the one-step method. Moreover, the finer MMT migrates more readily to the interface to cause a much smoother phase interface. However, a secondary crystallization peak appears when the shear force is not sufficient enough to make MMT finely dispersed, in case of the two-step method and the MMT content is increased to 3 wt. %. The mixing temperature shows little effect on the acceleration of MMT on the crystallization of PTT/PC compared with the shear force. Only when MMT did not exfoliate or uncomplete did the presence of epoxy resin help to promote crystallization because of the improved MMT dispersion.

Non-Isothermal Crystallization Kinetics of Montmorillonite/Polyamide 610 Nanocomposites

“…They demonstrated that adding MMT with strong nucleation activity might lower the crystallization activation energy of iPP while increasing its crystallization rate. By using MMT as a crystallization aid (MMT content: 1 wt%), Xue et al investigated the crystallization behavior of PTT/PC blends [ 28 ]. They discovered that uniformly exfoliated and distributed MMT contributed considerably to the crystallization of PTT.…”

Effect of POSS-Modified Montmorillonite on Thermal, Mechanical, and Electrical Properties of Unsaturated Polyester Nanocomposites

“…Montmorillonite (MMT) is one such form of nanoclay phyllosilicate mineral possessing one O–Al(Mg)–O octahedral sheet sandwiched between two O–Si–O tetrahedral sheets [ 13 ]. MMT-based polymer nanocomposites have been under constant scrutiny in recent years owing to its high aspect ratio, cation exchange capacity, superior surface area, and small particle size [ 14 ]. However, MMT reinforcement within a polymer matrix suffers certain impediments in the form of agglomeration which influences the dispersion and exfoliation of MMT in the polymer matrix.…”