Nanocomposites of poly(vinyl chloride) have been prepared using both hectorite-and bentonite-based organically-modified clays. The organic modification used is tallow-triethanol-ammonium ion. The morphology of the systems was investigated using X-ray diffraction and transmission electron microscopy and these systems show that true nanocomposites, both intercalated and exfoliated systems, are produced. The mechanical properties have been evaluated and the modulus increases upon nanocomposite formation without a significant decrease in tensile strength or elongation at break. Thermal analysis studies using thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis were conducted. Thermal stability of the PVC systems was assessed using a standard thermal process evaluating the evolution of hydrogen chloride and by color development through the yellowness index. Cone calorimetry was used to measure the fire properties and especially to evaluate smoke evolution. The addition of an appropriately-modified bentonite or hectorite nanoclay leads to both a reduction in the total smoke that is evolved, and an increase in the length of time over which smoke is evolved. Along with this, a reduction in the peak heat release rate is seen. It is likely that the presence of the clay in some way interferes with the cyclization of the conjugated system formed upon HCl loss.

Assessing the degree of organoclay delamination and layer alignment is crucial to deliver consistent properties of nanocomposite materials. A simple infrared technique is discussed that permits quantitative determination of these organoclay dispersion parameters in a nanocomposite. This technique complements other existing methods to optimize process conditions to fully achieve the advantages that high purity hectorite nanoclays can bring to plastic nanocomposites. POLYM. ENG. SCI., 46: 1031-1039, 2006.

Nanoclay applications in poly(vinyl chloride) (PVC) have been limited, as the organic modifier of conventional nanoclays can promote PVC degradation. Novel nanoclays designed for enhanced PVC compatibility were compounded with PVC. Hectorite and bentonite clays were studied as nanoclay fillers. Two incorporation methods were evaluated to determine the effect on nanoclay dispersion and composite performance. A two‐stage method, in which the nanoclay was predispersed in plasticizer, resulted in good nanoclay dispersion at both the micrometer and nanometer scales. The nanocomposites were characterized by using a wide range of analytical tools. They exhibited significantly improved heat stability, an increase of up to 200% in storage modulus, and a decrease of up to 77% in oxygen permeation, as compared to unfilled PVC. Bentonite nanoclays provided a greater increase in barrier and mechanical properties. No change was seen in the PVC glass transition temperature. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers

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The morphology and rheology of ternary isotactic polypropylene (PP)/polyamide‐6 (PA‐6)/glass blends is investigated and contrasted with the behavior of two‐component (binary) PP/PA‐6 blends. Injection molded samples of binary blends exhibit an interlayer slip morphology for both PP and PA‐6 as the matrix and the blend shear viscosity is lower than expected from a rule of mixtures. The morphology of ternary blends is dependent on the choice of the matrix phase. In ternary blends with a PA‐6 matrix, the PP domains and glass fibers are separately dispersed within the matrix. In ternary blends with a PP matrix, the PA‐6 is mainly found surrounding (encapsulating) the glass fibers, and the extent of the interlayer slip morphology is reduced. Variations in glass surface treatment, blending time, and order of addition did not affect the rapid encapsulation of glass by the PA‐6. A reduction in blending temperature, below the peak PA‐6 melting temperature, hinders encapsulation.