Džunuzović Jasna V, Stefanović Ivan S, Džunuzović Enis S, Kovač Tijana S, Malenov Dušan P, Basagni Andrea, Marega Carla
Center of Excellence in Environmental Chemistry and Engineering, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia.
Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia.
Polymers (Basel). 2024 Jun 26;16(13):1812. doi: 10.3390/polym16131812.
The benefit of being acquainted with thermal properties, especially the thermal stability of polyurethanes (PU), and simplified methods for their improvement is manifold. Considering this, the effect of embedding different amounts of unmodified and surface-modified TiO nanoparticles (NPs) within PU, based on polycaprolactone (PCL) and Boltorn aliphatic hyperbranched polyester, on PU properties was investigated. Results obtained via scanning electron microscopy, swelling measurements, mechanical tests and thermogravimetric analysis revealed that TiO NPs can be primarily applied to improve the thermal performance of PU. Through surface modification of TiO NPs with an amphiphilic gallic acid ester containing a C12 long alkyl chain (lauryl gallate), the impact on thermal stability of PU was greater due to the better dispersion of modified TiO NPs in the PU matrix compared to the unmodified ones. Also, the distinct shape of DTG peaks of the composite prepared using modified TiO NPs indicates that applied nano-filler is mostly embedded in soft segments of PU, leading to the delay in thermal degradation of PCL, simultaneously improving the overall thermal stability of PU. In order to further explore the thermal degradation process of the prepared composites and prove the dominant role of incorporated TiO NPs in the course of thermal stability of PU, various iso-conversional model-free methods were applied. The evaluated apparent activation energy of the thermal degradation reaction at different conversions clearly confirmed the positive impact of TiO NPs on the thermal stability and aging resistance of PU.
了解热性能的益处，特别是聚氨酯（PU）的热稳定性以及改进它们的简化方法是多方面的。考虑到这一点，研究了在基于聚己内酯（PCL）和超支化脂肪族聚酯Boltorn的PU中嵌入不同量的未改性和表面改性的TiO纳米颗粒（NPs）对PU性能的影响。通过扫描电子显微镜、溶胀测量、力学测试和热重分析获得的结果表明，TiO NPs主要可用于提高PU的热性能。通过用含有C12长烷基链的两亲性没食子酸酯（月桂基没食子酸酯）对TiO NPs进行表面改性，与未改性的TiO NPs相比，改性TiO NPs在PU基体中具有更好的分散性，因此对PU热稳定性的影响更大。此外，使用改性TiO NPs制备的复合材料的DTG峰的独特形状表明，所应用的纳米填料大多嵌入到PU的软段中，导致PCL热降解延迟，同时提高了PU的整体热稳定性。为了进一步探索所制备复合材料的热降解过程，并证明掺入的TiO NPs在PU热稳定性过程中的主导作用，应用了各种等转化率无模型方法。在不同转化率下评估的热降解反应的表观活化能清楚地证实了TiO NPs对PU热稳定性和抗老化性的积极影响。
