Mechanical properties of attapulgite clay reinforced polyurethane shape-memory nanocomposites

Mechanisms of the Shape Memory Effect in Polymeric Materials

“…[4,7,9,10,25,37,43,139,148,149], based on the principles of the above discussed working mechanisms, the performance of existing materials can be optimized by means of controlling the processing parameters in programming [113,126,150]. Figure 30 illustrates the influence of the programming temperature on shape fixity ratio (R f ) and shape recovery ratio (R r ).…”

Barrier and Mechanical Properties of Clay-Reinforced Polymeric Nanocomposites

“…However, biopolymer films have exhibited relatively poor mechanical and water vapor barrier properties when compared to traditional polymeric films, therefore limiting their commercial use [4] . In the last years polymer=clay composites have received much attention, because of their extraordinary possibility to improve the barrier [5][6][7][8] , and mechanical properties [9][10][11][12] of films. These composites are a class of hybrid materials composed of organic polymer matrices and micro=nanoscale organophilic clay fillers [13] and due to their high aspect ratios and high surface area, if clay particles are properly dispersed in the polymer matrix at a loading level of 1-5% (w=v) unique combinations of physical and chemical properties will be obtained, that turn these composites attractive for making films and coatings for a variety of industrial applications [14] .…”

Thermal-Mechanical Properties of Polyurethane-Clay Shape Memory Polymer Nanocomposites

“…The attapulgite clay was heat-treated in an furnace (in air) at 850 °C for 2 hours [20,21], and then held in an oven at 100 °C for 12 hours. High resolution transmission electron microscopy (HR-TEM, JEOL 2010F) showed that the treated nano-clay formed a three-dimensional bundled network structure in which the length of single clay fibre varied from sub-micrometer to a few micrometers and the diameter was in the order tens of nanometres (see Figure 1(a)).…”

“…Our previous results showed that heat treated attapulgite nanoclay could significantly enhance mechanical properties of PU shape memory polymer [20]. Heat-treatment of the nano-clay removed the moisture and most surface hydroxyl groups, resulted in a crystallized and bundled structure, improved the interface between polymer and nano-fillers, and enhanced the mechanical properties of the nanocomposites [20]. Detailed studies on microstructure and thermal mechanical performance of the nanocomposites may provide useful guides for their engineering applications.…”

“…Its high aspect ratio and large surface area make it effectively reinforce the polymer matrix [19]. Our previous results showed that heat treated attapulgite nanoclay could significantly enhance mechanical properties of PU shape memory polymer [20]. Heat-treatment of the nano-clay removed the moisture and most surface hydroxyl groups, resulted in a crystallized and bundled structure, improved the interface between polymer and nano-fillers, and enhanced the mechanical properties of the nanocomposites [20].…”