Thermal Stability Of Thermoplastic Polyurethane Research Articles

Phosphate-Functionalized Silica for Improved Flame Retardancy and Thermal Stability of Thermoplastic Polyurethane

Phosphate-Functionalized Silica for Improved Flame Retardancy and Thermal Stability of Thermoplastic Polyurethane

A novel triazine-based covalent organic framework: Enhancement fire resistance and mechanical performances of thermoplastic polyurethanes

In this study, we decided to synthesize a flame-retardant triazine-based covalent organic framework (FT-COF) via solvothermal reaction, to improve the fire safety and mechanical properties of thermoplastic polyurethane (TPU). By adding 3.0 wt% of FT-COF, the tensile strength and elongation of TPU increased by 69% and 12%, respectively. After incorporating of FT-COF nanoparticles, the thermal stability of TPU was significantly improved that resulted in the increasing of char residue up to 158% for TPU/FT-COF 3%. With addition of 3.0 wt% FT-COF, the peak heat release rate, total heat release of TPU composite were dramatically decreased by 51.6% and 47.3%, respectively. Besides, the TPU/FT-COF 3% indicated distinct reductions in the total smoke release (41.1%) and the peak of carbon monoxide production rate (43.53%). This study offers a new plan to outstandingly reducing the flammability of TPU, thus developing its industrial usage.

Effects of flame retardants integrated with citrate and ammonium polyphosphate on thermal stability and flame retardancy of thermoplastic polyurethane elastomer

Three citrates, which incorporate cobalt citrate (CoC), copper citrate (CuC), and yttrium citrate (YC), were combined with ammonium polyphosphate (APP) as a flame retardant to improve the flame retardancy and thermal stability of thermoplastic polyurethane (TPU). The cone calorimeter test (CCT) results demonstrated that the PHRR (peak heat release rate) values of TPU‐2, TPU‐3, and TPU‐4 were decreased from 271.4 kW/m2 for TPU‐1 to 188.0, 256.9, and 219.0 kW/m2, respectively. Besides, compared with TPU‐1, the release of CO and CO2 of TPU composites that containing citrate were decreased. The limiting oxygen index (LOI) value for TPU‐1 (containing 8.0 wt% APP) was 26.5% while that of TPU‐4 was increased to 27.5% and reached to V‐0 rating on the vertical burning test. Thermogravimetric analysis (TG) indicated that containing both APP and citrate accelerated the degradation of TPU composites but increased the char residue. In detail, the char residue of TPU‐0 was 6.3 wt% at 685°C, while that of TPU‐3 was reached to 45.2 wt% at N2 atmosphere. Laser Raman spectroscopy (LRS) showed that the degree of graphitization of TPU composites had been increased after adding the citrates. X‐ray photoelectron spectrometer (XPS) and gas chromatography/mass spectrometry (GC‐MS) illustrated that citrate and APP exerted barriers effect in the condensed phase. This work provided a new way of flame retardant that integrated with citrate and APP for TPU composites.

Flame Retardancy of Thermoplastic Polyurethane Using Phosphorus-containing Flame Retardants

A new phosphorus-containing polymer was synthesized and applied as a flame retardant in the polyether thermoplastic polyurethane (TPU). This flame retardant combined with two commercial flame retardants of melamine pyrophosphate (MPP) and melamine cyanurate (MCA) were also used in TPU. Their flame retardancy, thermal degradation and structural feature were investigated by limiting oxygen index (LOI), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The experimental data showed that the presence of phosphorus-containing flame retardant improve the limiting oxygen index, thermal stability and fire behavior. The LOI value of TPU including 20 wt% synthesized phosphorus-containing flame retardant and 20 wt% MCA was increased to 25.8. The thermal stability of TPU was also excellently improved comparing with the neat TPU. A maximum char residue was obtained when 20 wt% synthetic flame retardant and 20 wt% MPP were added into the TPU which the char yields were 18.7%. The combustion heat results showed that the value of neat TPU is highest than other TPUs by adding the different flame retardants. The SEM results showed that a dense char layer was obtained by adding the synthetic phosphorus-containing flame retardant and MCA with 20 wt % respectively into the TPU system.

Mechanical, thermal and rheological properties of hollow glass microsphere filled thermoplastic polyurethane composites blended by normal vane extruder

In this study, different proportions of hollow glass microsphere (HGM) filled thermoplastic polyurethane (TPU) elastomer composites were prepared by normal vane extruder. The phase morphology, rheological properties, mechanical properties and thermal stability of TPU/HGM composites were investigated in detail. It was observed that the incorporation of HGM increased the thermal stability of TPU. With the increase in HGM content from 5 to 20 wt-%, the glass transition temperature, storage modulus and complex viscosity values increased continuously, while the density of the composite monotonously decreased. Moreover, the tensile modulus of the composites increased from 43.5 to 81.3 MPa. The results showed that, although raw HGM was used without any modification, the HGM played an important role in improving the properties of TPU.