Nanoclay effect on transport properties of thermoplastic polyurethane/polypropylene (TPU/PP) blends

Preparation of PLA-TPU-Nanoclay composites and characterization of their morphological, mechanical, and shape memory properties

In this study, a combination of polylactic acid polymer and thermoplastic polyurethane with the addition of nano-clay particles was used. The reason for using clay nanoparticles and their strength is the low price and availability of this material. Adding nano-clay particles to the polymer composition improves the mechanical properties of the composite as they will interact with functional groups of the polymer. The results of the FTIR spectroscopy confirmed the presence of three components in the compound indicating that no chemical reactions occurred among the three components during the compounding process. The FE-SEM images taken from the compounds showed that TPU and nano-clay particles were evenly distributed in the PLA matrix. The DMTA results were utilized to determine the transfer temperature of the compounds as well as the storage and loss modulus and the shape memory properties. The XRD spectroscopy was used to determine the crystallinity and exfoliation of the nanoparticles. The mechanical properties of the fabricated polymer compounds were determined. It was found that the sample with 3% by weight of clay nanoparticles had the highest strength, and the sample with 5 wt% of clay nanoparticles had the highest toughness among nanocomposites. According to the hardness measurement, the sample with 5% by weight of clay nanoparticles has the highest hardness amongst all prepared composites. The memory properties of the prepared nanocomposites showed a significant improvement with increasing the amount of nanoparticles. This study showed the suitability and efficiency of PLA, TPU, and clay nanoparticle melt mixing methods in achieving a relatively tough shape memory composite. At the same time, this method is also inexpensive and scalable.

One More Step towards a Circular Economy for Thermal Insulation Materials-Development of Composites Highly Filled with Waste Polyurethane (PU) Foam for Potential Use in the Building Industry

The rapid development of the building sector has created increased demand for novel materials and technologies, while on the other hand resulting in the generation of a severe amount of waste materials. Among these are polyurethane (PU) foams, which are commonly applied as thermal insulation materials. Their management is a serious industrial problem, due to, for example, their complex chemical composition. Although some chemical and thermochemical methods of PU foam recycling are known, their broader use is limited due to requirements related to the complexity and safety of their installation, thus implicating high costs. Therefore, material recycling poses a promising alternative. The incorporation of waste PU foams as fillers for polymer composites could make it possible to take advantage of their structure and performance. Herein, polypropylene-based composites that were highly filled with waste PU foam and modified using foaming agents were prepared and analyzed. Depending on the foam loading and the foaming agent applied, the apparent density of material was reduced by as much as 68%. The efficient development of a porous structure, confirmed by scanning electron microscopy and high-resolution computed micro-tomography, enabled a 64% decrease in the thermal conductivity coefficient. The foaming of the structure affected the mechanical performance of composites, resulting in a deterioration of their tensile and compressive performance. Therefore, developing samples of the analyzed composites with the desired performance would require identifying the proper balance between mechanical strength and economic, as well as ecological (share of waste material in composite, apparent density of material), considerations.

Morphology and Thermal Behavior of TPU/PP Blends Modified with Maleic Anhydride Grafted SEBS-g-MA Block Copolymer

The effect of the maleic anhydride grafted styrene-ethylene/butylene-styrene (SEBS-g-MA) block copolymer on the properties of thermoplastic polyurethane (TPU) and polypropylene (PP) blends were studied. TPU/PP and TPU/PP/SEBS-g-MA blends with different weight ratios were prepared in a twin-screw extruder. The thermal properties of the blends were investigated via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The morphological structure of the blends as well as the effect of SEBS-g-MA block copolymer on the reduction of domain size and particle dispersion were investigated via scanning electron microscopy (SEM). The results from the uncompatibilized blends clearly indicated immiscibility of TPU and PP resulting in undesirable properties. The thermal properties of TPU/PP blends were improved by compatibilization with SEBS-g-MA. Addition of the SEBS-g-MA block copolymer resulted in a finer dispersion of the minor phase and clearly improved interfacial adhesion.