Crystallization kinetics of polyamide 11 in the presence of sepiolite and montmorillonite nanofillers

Abstract

The crystallization kinetics of polyamide 11 (PA 11) in presence of sepiolite and organomodified montmorillonite nanofillers has been studied in a wide range of temperatures and cooling rates by conventional differential scanning calorimetry (DSC) and fast scanning chip calorimetry (FSC). The presence of the nanofillers has a negligible effect on the crystallization temperature of PA 11 at low cooling rates. However, at rapid cooling conditions a distinct nucleating effect of the nanofillers is detected. The critical cooling rate to suppress crystallization increases from 600 K s -1 to about 1000 and 3000 K s -1 in nanocomposites containing sepiolite and montmorillonite, respectively. Regardless the cooling rate applied for solidification the melt, in the nanocomposites the crystallinity of PA 11 is 5 to 10 % higher than in neat PA 11, with the highest values obtained for the montmorillonite-containing system. The nucleating effect of the nanofillers onto the crystallization of the PA 11 is confirmed by analysis of the half-times of isothermal crystallization, and by analysis of the spherulitic superstructure. All measurements proved a saturation of the nucleation efficiency at a loading of the nanofiller of 2.5 m%.

Effect of expandable and expanded graphites on the thermo-mechanical properties of polyamide 11

“…In the producer's datasheet, a mean particle width of about 300 mm is reported. According to the indications reported in the article of Focke et al, 11,27 expanded graphite (EG) was prepared by treating NEG powder at high temperature for 5 min, by placing it in a muffle furnace set at 700 C, at atmospheric pressure.…”

“…[7][8][9] Polymer nanocomposites attracted a great deal of attention and have been the focus of study for a large number of research groups. [10][11][12][13][14] In recent years, polymer-based nanocomposites reinforced with expandable graphite have received much attention by both scientific and industrial communities due to their enhanced mechanical performances, electrical conductivity and barrier properties as well as flame resistance over neat polymers. 15 The reasons for the observed behaviour depend on the structure of natural graphite where the atoms in a plane are strongly bonded in an hexagonal structure but weakly bonded normal to that plane.…”

Polyamide 11/Poly(butylene succinate) Bio-Based Polymer Blends

“…Many research efforts have been devoted to improve the properties of PA 11, mainly through incorporation of inorganic fillers [12,13,14,15,16,17,18], or by blending with other, especially bio-based polymers, like poly( l -lactic acid), or polyhydroxyalcanoates to further expand the application range [19,20]. Among the various bio-based polymers, blends of PA 11 with poly(butylene succinate) (PBS) have barely been investigated.…”

Recent Progress in Hybrid Biocomposites: Mechanical Properties, Water Absorption, and Flame Retardancy

“…PA11 is a semi-crystalline polymer that is rigid at room temperature with a glass transition temperature (Tg) of 43 °C [ 111 ]. Various efforts have been reported to improve the properties of PA11 that most of them have focused on the blending of PA11 with other polymers, especially bio-based ones like PLA [ 109 , 112 , 113 ], PHA [ 114 , 115 ] and PBS [ 108 , 116 ] and also the incorporation of PA11 with inorganic fillers [ 117 , 118 , 119 ].…”