Preparation of polypropylene/montmorillonite nanocomposites with an exfoliated structure by a designed route

Abstract

Nanocomposites of polypropylene (PP) and montmorillonites (MMT) were prepared by solid-phase grafting reactive organomontmorillonite (ROMT) and polar monomers onto powdered PP and melt-blending granule PP with the master batches as PP/MMT grafting copolymers (PPMG). The structure and properties of the PP/ MMT nanocomposites (PPMN) were investigated by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) patterns, transmission electron microscopy (TEM), dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetric analysis. GPC showed that the numerical molecular weight and polydispersity of the graft copolymers of PPMG were approximately 4793 and 2.197, respectively. FTIR confirmed the solid-phase graft copolymerization. XRD and TEM indicated the formation of the exfoliated, layered silicates (tactoids). The mole ratio of compound alkylammoniums and the exothermic enthalpy from solid-phase graft copolymerization played key roles in the formation of tactoids. The optimum mole ratio of organophilic alkylammonium to reactive alkylammonium was 3 : 1. The mechanical and thermal properties increased with the contents of PPMG, and a preferable state was achieved at approximately 8 phr PPMG (parts of reagent per 100 parts of PP) because of the plastification of the exfoliated silicates and the graft copolymers.

Investigation of the influence of processing conditions on the thermal, rheological and mechanical behavior of polypropylene nanocomposites

“…Results obtained from DSC measurements for PP nanocomposites are presented in Table 2. According to Hong et al [30] the first melting temperature ( T M1 ) can be referred to the formation of the β‐phase of PP, because MMT improves the heterocrystallization of these PP nanocomposites. It can be seen that the melting points of these nanocomposites are nearly constant (see Table 2).…”

“…The increasing melt enthalpies (Δ H ) of the second melting peak ( T M2 ) from first to second heating can be interpreted as differences in thermal treatment in the kneading process compared to the preparation in the DSC measurements [30].…”

“…So, the rheology is a powerful tool for fundamental insights about the state of dispersion, because the rheological values (storage modulus G ′, loss modulus G ″ and complex viscosity η*) are sensitive to the dispersion of the dispersed phase. It offers a method to assess the state of dispersion of PNCs directly in the melt state [19, 28, 30–36]. According to Wu and Zheng [37] and Pham et al [38], a filled polymer system develops a percolation network under oscillatory deformation.…”

Preparation and properties of wood plastic composites based on tea residue

“…And one way to enhance the interfacial interaction within composites is functional reaction to the non‐polar plastic , such as grafting process. For example, the maleic anhydride‐grafted PP (MAH‐g‐PP) is a renowned and widely utilized graft copolymer as a modifier to boost the compatibility between biofibers and PP .…”

Study on the nonisothermal crystallization kinetics of ternary-monomer solid-phase graft copolymer of polypropylene

“…Recently, some researchers have developed the multimonomer solid-phase graft copolymers, [11][12][13][14][15][16] which have higher graft degree than the individual monomer graft copolymer. Of these researchers, Jia and coworkers [14][15][16] have developed the ternary-monomer solid-phase graft copolymer, which has the advantages of high graft degree, long graft chains and adjustable side chains and has shown outstanding interfacial compatibilization for the polyolefin composites and blends. 15,16 It is well known that the properties of PP depend significantly on its crystallization behaviors.…”