Although polymer blend nanocomposites are widely studied, the balance between stiffness and toughness has not yet been investigated in detail. Some materials producers as well as some sectors in the automotive industry try to improve the toughness of materials without an important loss in stiffness. With this in mind, the aim of the study reported here was to obtain a good balance between toughness and stiffness of polymer blends with different amounts of clay and compatibilizer. In this context, the microstructure of polyamide 6/ethylene–propylene–diene metallocene terpolymer/(ethylene–propylene–diene copolymer)‐graft‐(maleic anhydride) blends with various amounts of clay (2, 3, 4 and 5 wt%) and compatibilizer (10 and 20 wt%) was studied to analyse the achieved morphology to understand the macroscopic properties. The morphology of the rubber phase and the dispersion of the montmorillonite (MMT) are the main factors that influence the mechanical properties. In this sense, the highest Young's modulus is achieved for nanoblends with 5 wt% of MMT, although this nanoblend has the lowest value of notched Izod impact strength. The results obtained suggest that there is a clear trade‐off between stiffness, toughness and temperature behaviour when the ratio of (ethylene–propylene–diene copolymer)‐graft‐(maleic anhydride) to MMT is 5:1. Copyright © 2009 Society of Chemical Industry

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The structure of the PA6/mEPDM/EPDMgMA/organoclay ternary hybrids was characterized and related to its properties. The nanoblends were prepared through four different blending sequences based on one-or two-step processes: (1) The PA6/organoclay nanocomposite was prepared and then mixed with the mEPDM1 EPDMgMA compound; (2) the mEPDM1EPDMgMA1 organoclay compound was first prepared and then mixed with PA6; (3) the PA6, mEPDM, EPDMgMA, and organoclays were blended in one step; and (4) the PA6/mEPDM/EPDMgMA blend was prepared and then mixed with the organoclay. The microscopic study of the nanoblends showed a relationship between the blending sequence and the dispersion of the organoclay and the rubber. Nevertheless, the mechanical characterization showed slight differences between the blending sequence because of the presence of the organoclay in the matrix, rubber, or interface.

a b s t r a c tIn an effort to understand the influence of the shape and area of the nanoclay type used in the in situ polymerization process, two different types of clays (fibrillar and laminar) were employed to obtain nanocomposites. The preliminary results demonstrated that a needlelike shaped clay promotes higher molar mass and better mechanical properties compared with laminar clay. The ultra-high molecular weight of sepiolite/nanocomposites introduces significant problems with processability. Therefore, a new method of polymerization was designed to include two significant changes. The first change was related to the use of a non-isothermal temperature profile and the second to the addition of an additional amount of non-anchored co-catalyst leading to materials with higher fluidity.

In this study, the effectiveness of three random copolymers based on blocks of poly(lactic acid) and polyethylene (PLA‐PE) used as compatibilizer in PLA and high density polyethylene blends (PLA/HDPE) was evaluated in terms of thermal and mechanical properties. The compatibilizers were synthesized by different ways: reactive extrusion (C1), ring opening polymerization of lactide with PE with —OH substituent group (PE‐OH) as initiator (C2) and polycondensation of lactic acid in presence of PE grafted with maleic anhydride (PE‐g‐MAH) (C3). The compatibilizers were used in two different proportions (5 and 15 wt%) and their efficiency was compared with a commercial compatibilizer (C0). The blends with C2 compatibilizer exhibited the highest tensile toughness (350% of increment compared with neat PLA/PE) because of the morphology attained. However, it was found that a relationship exists between the improvement of the compatibility and the loss of the thermal stability (−28°C) in PLA/HDPE blends. POLYM. ENG. SCI., 54:522–530, 2014. © 2013 Society of Plastics Engineers