Morphological and Tribological Properties of PMMA/Halloysite Nanocomposites

From an environmental and cost-effective perspective, a number of research challenges can be found for electronics, household, but especially in the automotive polymer parts industry. Reducing synthesis steps, parts coating and painting, or other solvent-assisted processes, have been identified as major constrains for the existing technologies. Therefore, simple polymer processing routes (mixing, extrusion, injection moulding) were used for obtaining PMMA/HNT nanocomposites. By these techniques, an automotive-grade polymethylmethacrylate (PMMA) was modified with halloysite nanotubes (HNT) and an eco-friendly additive N,N′-ethylenebis(stearamide) (EBS) to improve nanomechanical properties involved in scratch resistance, mechanical properties (balance between tensile strength and impact resistance) without diminishing other properties. The relationship between morphological/structural (XRD, TEM, FTIR) and tribological (friction) properties of PMMA nanocomposites were investigated. A synergistic effect was found between HNT and EBS in the PMMA matrix. The synergy was attained by the phase distribution resulted from the selective interaction between partners and favourable processing conditions. Modification of HNT with EBS improved the dispersion of nanoparticles in the polymer matrix by increasing their interfacial compatibility through hydrogen bonding established by amide groups with aluminol groups. The increased interfacial adhesion further improved the nanocomposite scratch resistance. The PMMA/HNT-EBS nanocomposite had a lower coefficient of friction and lower scratch penetration depth than PMMA/HNT nanocomposite.Financial support by the EU Commission through Project H2020-686165-IZADINANO2INDUSTRY is gratefully acknowledged

The Effect of SEBS/Halloysite Masterbatch Obtained in Different Extrusion Conditions on the Properties of Hybrid Polypropylene/Glass Fiber Composites for Auto Parts

Masterbatches from a linear poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) and halloysite nanotubes (HNT-QM) were obtained in different conditions of temperature and shear using two co-rotating twin-screw extruders. The influence of screw configuration and melt processing conditions on the morpho-structural, thermal and mechanical properties of masterbatches at macro and nanoscale was studied. A good dispersion of halloysite nanotubes and better thermal stability and tensile and nanomechanical properties were obtained at a lower temperature profile and higher screw speed. The effect of masterbatches, the best and worst alternatives, on the properties of a polypropylene (PP)–glass fiber (GF) composite was also evaluated. Double hardness, tensile strength and modulus and four times higher impact strength were obtained for PP/GF composites containing masterbatches compared to pristine PP. However, the masterbatch with the best properties led further to enhanced mechanical properties of the PP/GF composite. A clear difference between the effects of the two masterbatches was obtained by nanoindentation and nanoscratch tests. These analyses proved to be useful for the design of polymer composites for automotive parts, such as bumpers or door panels. This study demonstrated that setting-up the correct processing conditions is very important to obtain the desired properties for automotive applications

A Concrete and Viable Example of Multimaterial Body: The Evolution Project Main Outcomes

Funded by the EC FP7 Programme, EVolution project demonstrated that it is possible to consistently reduce the vehicle weight through the wide use of new materials and process technologies, mainly by developing a multi-material Body-in-White. This paper focuses on three of the five structural body demonstrators, the main objective of the framework, strongly hybridized with aluminum and thermoplastic composite materials, specifically developed and manufactured through innovative technologies. Directing in particular the analysis on medium production volumes (> 30,000 units/year), the industrial viability is evaluated in terms of TAKT time, lightweighting costs, weight reduction and structural performances achieved.The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 314744

SAXS investigation of structure-property relationship of polypropylene/montmorillonite composites during load cycling

Polypropylene (PP) can hardly be reinforced by the layered silicate montmorillonite (MMT), but the material fatigue appears somewhat reduced. The probable reason is amplified competitive nucleation of the PP by MMT component. Utilizing small-angle X-ray scattering (SAXS) from synchrotron, we investigate the nanostructure evolution of the PP in straining experiments from neat PP and compatibilized composite materials. The compatibilizer is a styrene–ethylene/butylene–styrene copolymer (SEBS). Oriented injection-molded test bars are studied.The discrete SAXS probes variations of sizes and distances among those crystalline domains that are not placed at random. Crystallite dimensions and distances are documented for modeling purposes. The nanoscopic strain is computed from the distance variation and compared with the macroscopic strain. Differences between macroscopic and nanoscopic strain are observed. They require postulating regions with statistical placement of crystallites (poorly arranged region, PAR) in addition to the SAXS-probed well-arranged semi-crystalline entities (WAE). The extensibility of WAEs must be different from that of the PARs. In neat PP, the observed WAEs are well developed and stronger than the PARs. In the composites, the WAEs are made from thin and less extended crystalline domains. They are weaker than the PARs that appear reinforced. Thus, enclosing each MMT layer a PAR is formed, and the WAEs generated farther away remain imperfect. Consequently, in the composites, the narrow crystalline domains from the WAEs do not break into even smaller pieces, and the fatigue of the composites is lower than that of the neat P