Poly(vinyl chloride)/metallic oxides/organically modified montmorillonite nanocomposites: Preparation, morphological characterization, and modeling of the mechanical properties

Abstract

Poly(vinyl chloride), metallic oxides (from copper, molybdenum, and zinc), and organically modified montmorillonite (O-MMT) nanocomposites were prepared in a melt-blending or intercalation-in-the-molten-state process. The morphology of the nanocomposites was evaluated with X-ray diffraction (XRD) and transmission electron microscopy (TEM). Properties, such as the mechanical, thermal, and electrical properties, and the dynamic thermal stability against dehydrochlorination were also evaluated. Nanocomposites with a hybrid intercalated/exfoliated structure were obtained in all of the situations considered, as demonstrated by the XRD and TEM results and indirectly by the increment of Young's modulus of the formulations with increasing amount of O-MMT incorporated. The modeling of Young's modulus by the Halpin-Tsai, HuiShia, and Lewis-Nielsen theories showed that the process of nanocomposite preparation allowed the aspect ratio of the clay particles to increase; these values were comparable to those nanocomposites obtained by other researchers with different polymeric matrices and methodologies.

Metallic oxides as fire retardants and smoke suppressants in flexible poly(vinyl chloride)

“…This change in CO production behavior and the reduction in MEHC (except for the case of interaction between copper and zinc) is further evidence of change in the samples' combustion mechanism as a result of the compositional factors, leading to the belief that a less rich fuel and an incomplete combustion mechanism are introduced in the system 33, 34. The MEHC results obtained herein, despite statistical consistency and coherence with another study we recently published,27 are the opposite of those obtained by Li and Wang21, 23–26 in studies using copper and molybdenum oxides incorporated into a rigid PVC compound. According to these authors, volatile substances of easier combustion are formed as a result of the presence of metallic oxides, which would explain the increase in MEHC values.…”

“…A simple check of Table III shows that all of the oxides studied have statistical significance in relation to char residue (CR) quantity values. To normalize the values for the diverse formulations studied, an additional column is shown in Table III corresponding to the normalized char residue (NCR) value for each formulation 27. The NCR value was determined by multiplying the CR value, measured in the cone calorimetric assay by the mass fraction of reference PVC composite in each formulation as per data shown previously in Table II.…”

“…Smoke suppressors in PVC, based on molybdenum and copper, were previously studied by Starnes Jr. and coworkers,10–15 Kroenke and Lattimer,16–20 and Li and Wang 21–26. In a previous work,27 the authors presented the combustion and degradation properties of PVC/metallic oxides/O‐MMT nanocomposites, and concluded that the effects of a ternary mixture of CuO/MoO 3 /ZnO is significantly more efficient in the reduction of heat release and smoke suppression of a flexible PVC compound. Morley8 also reports the commercial use of molybdenum and zinc compounds as smoke suppressors in PVC formulations, normally supported in inert fillers like calcium carbonate or talc.…”

Elastic and yield behaviors of recycled polypropylene-based composites: Experimental and modeling study

“…All the parameters for modeling the Young's modulus are summarized in Table 5 for different recycling numbers. Table 6 shows the reprocessing parameters in Equation (20) and Equation (13). Predicted compressive moduli for different testing temperatures are compared with the experimental data for the neat PP and PPbased composites with different recycling numbers in Figs.…”

“…E 0i are the three reference compressive moduli for non-recycled neat PP (Table 5). Similarly, the reprocessing dependent fillers' ARs were calculated by using Equation (13). In order to reduce the number of parameters, m i were taken the same values as those for the storage modulus predictions.…”