Hejna Aleksander, Olszewski Adam, Zedler Łukasz, Kosmela Paulina, Formela Krzysztof
Department of Polymer Technology, Gdańsk University of Technology, Gabriela Narutowicza 11/12, 80-233 Gdańsk, Poland.
Materials (Basel). 2021 Jan 21;14(3):499. doi: 10.3390/ma14030499.
The use of waste tires is a very critical issue, considering their environmental and economic implications. One of the simplest and the least harmful methods is conversion of tires into ground tire rubber (GTR), which can be introduced into different polymer matrices as a filler. However, these applications often require proper modifications to provide compatibility with the polymer matrix. In this study, we examined the impact of GTR oxidation with hydrogen peroxide and potassium permanganate on the processing and properties of flexible polyurethane/GTR composite foams. Applied treatments caused oxidation and introduction of hydroxyl groups onto the surface of rubber particles, expressed by the broad range of their hydroxyl numbers. It resulted in noticeable differences in the processing of the polyurethane system and affected the structure of flexible composite foams. Treatment with HO resulted in a 31% rise of apparent density, while the catalytic activity of potassium ions enhanced foaming of system decreased density by 25% and increased the open cell content. Better mechanical performance was noted for HO modifications (even by 100% higher normalized compressive strength), because of the voids in cell walls and incompletely developed structure during polymerization, accelerated by KMnO treatment. This paper shows that modification of ground tire rubber is a very promising approach, and when properly performed may be applied to engineer the structure and performance of polyurethane composite foams.
考虑到废旧轮胎对环境和经济的影响，其利用是一个非常关键的问题。最简单且危害最小的方法之一是将轮胎转化为胶粉（GTR），它可作为填料引入到不同的聚合物基体中。然而，这些应用通常需要进行适当改性以实现与聚合物基体的相容性。在本研究中，我们考察了用过氧化氢和高锰酸钾对GTR进行氧化处理对软质聚氨酯/GTR复合泡沫材料加工过程及性能的影响。所采用的处理方法导致橡胶颗粒表面发生氧化并引入了羟基，这可通过其广泛的羟值范围体现出来。这使得聚氨酯体系在加工过程中出现了显著差异，并影响了软质复合泡沫材料的结构。用过氧化氢处理使表观密度提高了31%，而钾离子的催化活性增强了体系的发泡，使密度降低了25%，并增加了开孔率。经过氧化氢改性的材料表现出更好的力学性能（归一化压缩强度甚至高出100%），这是由于在高锰酸钾处理加速聚合过程中，泡孔壁中存在空隙且结构发育不完全。本文表明，胶粉改性是一种非常有前景的方法，若操作得当，可用于设计聚氨酯复合泡沫材料的结构和性能。
