Properties of high‐impact polystyrene/organoclay nanocomposites synthesized via in situ polymerization

Abstract

High-impact polystyrene (HIPS)/organically modified montmorillonite (organoclay) nanocomposites were synthesized via in situ polymerization. The effects of the organoclay on the morphology and material properties of HIPS/organoclay nanocomposites were investigated. Xray diffraction and transmission electron microscopy experiments revealed that intercalation of polymer chains into silicate layers was achieved, and the addition of nanoclay led to an increase in the size of the rubber domain in the composites. In comparison with neat HIPS, the HIPS/organoclay nanocomposites exhibited improved thermal stability as well as an increase in both the complex viscosity and storage modulus. The presence of intercalated organoclay drastically enhanced the gas-barrier properties because of the increase in the tortuosity of the diffusive path for a penetrating gas molecule. Some mechanical properties, including the tensile modulus, were superior to those of conventional HIPS. Finally, the preparation of the nanocomposites with a minimal loss of impact properties was proposed through changes in the synthetic procedure.

The effects of processing and using different types of clay on the mechanical, thermal and rheological properties of high-impact polystyrene nanocomposites

“…The effect of the clay in enhancing thermal stability can be explained by the silicate layers with a high aspect ratio, which could hinder the diffusion of volatile degradation matter out of the polymer matrix. 18,30,34 From the results included in Figure 5a, it is clear that the temperature where the material is degraded by 10% (T 10% ) increases by as much as 25 1C with the addition of 2 wt% C30B, whereas a further increase in the C30B clay loading to 5 wt% does not improve the thermal stability of the nanocomposite material significantly. The differential thermogravimetric analysis (DTGA) curves showed a double peak when the HIPS material was undergoing degradation, indicating that there was a degradation mechanism taking place in two separate steps.…”

“…Other studies 5,14,30,31 have shown that the elongation at break is greatly decreased upon addition of clay. It can therefore be postulated that the decrease in the impact strength is a result of the organoclay degradation during melt processing, in which the collapsed organoclay structures cause a buildup of stress in the system.…”

“…32 In contrast, the reduction of impact strength is thought to be a result of the silicate portion existing within the rubber domain, which invalidates its ability to absorb energy when the material is subjected to impacting forces. 30,32 A comparison of 550B, 5100B and 5150B suggests that the tensile modulus undergoes the most significant changes of all of the properties analyzed. An increase in the rotor speed during mixing causes the tensile modulus to decrease, and this decline may be attributed to the degradation of the organoclay during melt processing.…”

“…The slope of the storage modulus is expected to have a value of 2, whereas the slope of the loss modulus is expected to have a value of 1 for monodispersed polymers, 26 which decreases to 0 for threedimensional nanocomposite structures. 30,35 Table 2 shows the slope of the storage modulus for HIPS and HIPS nanocomposites. The value of g 0 for HIPS is reported to be 1.42, with the deviation from a theoretical g 0 of 2 resulting from the polydispersity of HIPS.…”

Spherically shaped micron-size particle-reinforced PMMA and PC composites for improving energy absorption capability

“…Polymers exhibit inferior impact resistance, stiffness, and strength to weight ratio, compared to fibrous composites that are reinforced with fibers or yarns, which play a key role in introducing high impact resistance, and superior mechanical properties into the composite materials. Numerous attempts have been made to enhance both impact resistance and mechanical properties of polymer materials by blending two or more materials [8][9][10]. Polymethyl methacrylate (PMMA) and polycarbonate (PC) are often utilized for impact resistant polymer materials because they have good impact resistance as well as relatively good mechanical properties such as Young's modulus or tensile strength.…”