Arrigo Rossella, Antonioli Diego, Lazzari Massimo, Gianotti Valentina, Laus Michele, Montanaro Laura, Malucelli Giulio
Department of Applied Science and Technology and Local INSTM Unit, Politecnico di Torino, Viale T. Michel 5, 15121 Alessandria, Italy.
Department of Science and Technological Innovation, Università del Piemonte Orientale "A. Avogadro", Viale T. Michel 11, 15121 Alessandria, Italy.
Polymers (Basel). 2018 Oct 24;10(11):1182. doi: 10.3390/polym10111182.
Polyethylene glycol-based nanocomposites containing an organo-modified hydrotalcite with loadings ranging from 0.5 to 5 wt.% were prepared by melt mixing performed just above the melting point of the polymer matrix. In these conditions, the dispersion of the nanofiller within the polymer matrix was quite homogeneous as revealed by TEM analyses. The effect of various thermal treatments and filler loadings was thoroughly investigated by means of rheological, morphological and gas chromatography-mass spectrometry, hyphenated to thermogravimetry analysis tests. Unfilled polyethylene glycol exhibited a continuous decrease in complex viscosity upon heating. In contrast, the complex viscosity of nanocomposites containing nanofiller loadings higher than 1 wt.% showed first a decrease, followed by an increase in the complex viscosity as the temperature increases, exhibiting a minimum between 130 and 140 °C. Annealing at 180 °C for different times further increased the viscosity of the system. This unusual behavior was explained by the occurrence of grafting reactions between the ⁻OH terminal groups of the polyethylene glycol chains and the hydroxyl groups of the organo-modified filler, thus remarkably affecting the relaxation dynamics of the system.
通过在略高于聚合物基体熔点的条件下进行熔融共混，制备了负载量为0.5至5 wt.%的含有有机改性水滑石的聚乙二醇基纳米复合材料。在这些条件下，如透射电子显微镜分析所示，纳米填料在聚合物基体内的分散相当均匀。通过流变学、形态学以及与热重分析测试联用的气相色谱 - 质谱法，对各种热处理和填料负载量的影响进行了深入研究。未填充的聚乙二醇在加热时复数粘度持续下降。相比之下，纳米填料负载量高于1 wt.%的纳米复合材料的复数粘度首先下降，随后随着温度升高而增加，在130至140 °C之间出现最小值。在180 °C下进行不同时间的退火进一步提高了体系的粘度。这种异常行为是由聚乙二醇链的 -OH 端基与有机改性填料的羟基之间发生接枝反应所解释的，从而显著影响了体系的松弛动力学。
