ORIGINAL PAPER Polypropylene/organoclay nanocomposites prepared using a Laboratory Mixing Extruder (LME): crystallization, thermal stability and dynamic mechanical properties Achmad Chafidz & Mujtahid Kaavessina & Saeed Al-Zahrani & Mansour N. Al-Otaibi Received: 26 November 2013 /Accepted: 13 May 2014 /Published online: 24 May 2014 # Springer Science+Business Media Dordrecht 2014 Abstract Nanocomposites based on polypropylene and sur- face modified nanoclay (organoclay) masterbatch were pre- pared via melt blending using a Laboratory Mixing Extruder (LME). This work focused on the study of crystallization, thermal stability and dynamic mechanical properties of the nanocomposites. The effect of organoclay content (5, 10, and 15 wt.%) on non-isothermal and isothermal crystallization of the nanocomposites was studied by Differential Scanning Calorimetry (DSC). Thermal stability and dynamic mechani- cal properties of the nanocomposites were investigated by Thermogravimetric Analysis (TGA) and Dynamic Mechani- cal Analysis (DMA), respectively. The DSC results showed that the organoclay played an important role in the crystalli- zation of nanocomposites by acting as “nucleating agent” (heterogeneous nucleation). It was confirmed by the appear- ance of second crystallization peak, which was attributed to crystallization process induced by heterogeneous nucleation of organoclay. There were also a crystallization temperature shift, a reduction in half-time crystallization (t 1/2 ), and an increase of crystallization kinetic constants of the nanocom- posites. The TGA results showed that the addition of organoclay significantly increased the thermal stability of PP matrix, which was likely due to the characteristic and laby- rinth effect of layered silicates/clays dispersed in PP matrix, and also the formation of multilayered carbonaceous–silicate char. A well-known Coats-Redfern method was used to eval- uate the kinetic of thermal decomposition. Additionally, the stiffness characteristic of organoclay also greatly improved the dynamic mechanical properties (i.e. storage modulus, G′) of the nanocomposites. The DMA results demonstrated that the resistance and durability of PP/organoclay nanocomposites against applied stress and thermal were higher than the PP matrix. Keywords Nanocomposites . Organoclay . Masterbatch . Crystallization . Thermal stability . Dynamic mechanical Introduction Polymer nanocomposites (PNCs) represent a new class of composite materials. This type of composite materials is very popular among researchers in the field of polymer science and engineering. Polymer nanocomposites (PNCs) have attracted great attention because of their improved physical, thermal and mechanical properties compared to those of their conven- tional micro- and macro-composites [1]. The reason for these improved properties is the addition and dispersion of highly anisotropic nanofillers. Since the dispersed particle is in the nanometer scale, it is expected that there are more interfacial interactions between the nanofillers and the polymer matrix, which lead to an improvement of polymer properties [2]. Due to the small size of nanofillers, small amounts of nanofillers are sufficient to enhance the polymer properties without sig- nificant drawbacks on polymer density, optical transparency, and impact strength as compared with their conventional composites. These advantages compensate the negative effect of high cost of nanofillers [2–4]. Among the potential nanofillers, nanoclay or layered sili- cates (e.g. montmorillonite/MMT) is a type of nanofiller that has been widely used in the production of polymer nanocom- posites due to their abundance and being “green” additive. Layered silicate is made of several stacked layers, with a thickness around 1 nm, lateral dimension of 100–200 nm A. Chafidz : S. Al-Zahrani (*) : M. N. Al-Otaibi Chemical Engineering Department, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia e-mail: szahrani@ksu.edu.sa M. Kaavessina Chemical Engineering Department, Sebelas Maret University, Surakarta 57126, Indonesia J Polym Res (2014) 21:483 DOI 10.1007/s10965-014-0483-7