We investigated the rheological behavior of linear low-density polyethylene (LLDPE)/polylactic acid (PLA) blends in the presence of modified and non-modified silica nanoparticles in extensional flow. Characterization methods were used as Fourier transform infrared spectroscopy, scanning electron microscopy, and rheometric measurements under shear and uniaxial extensional flows. The rheology behavior of LLDPE significantly was changed by the addition of PLA and silica nanoparticles. Extensional results showed that the elongational viscosity of the blends intensified by the incorporation of silica nanoparticles. Strain hardening was observed for LLDPE containing 2 wt.% of the unmodified silica nanoparticles, which disappeared by enhancement of the unmodified silica from 2 to 8 wt.%. Furthermore, elongation thinning was observed for the filled blends at high loading, which was more sensitive to the strain rate by increasing of PLA. Surface modification of silica was demonstrated in different elongational behavior. Indeed, a fracture took place by loading the modified silica nanoparticles in LLDPE; however, the intensity of this behavior dramatically increased for filled blends with a high loading of modified silica. Graphical abstract

中文翻译：

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二氧化硅纳米粒子填充的低密度聚乙烯/聚乳酸共混物的伸长行为及其形貌

我们研究了线性低密度聚乙烯 (LLDPE)/聚乳酸 (PLA) 共混物在拉伸流中存在改性和非改性二氧化硅纳米粒子的情况下的流变行为。表征方法被用作傅里叶变换红外光谱、扫描电子显微镜和剪切和单轴拉伸流下的流变测量。通过添加 PLA 和二氧化硅纳米粒子，LLDPE 的流变行为发生了显着变化。拉伸结果表明，掺入二氧化硅纳米粒子后，共混物的拉伸粘度增强。对于含有 2 重量％未改性二氧化硅纳米粒子的 LLDPE 观察到应变硬化，通过将未改性二氧化硅从 2 重量％提高到 8 重量％，应变硬化消失。此外，在高载荷下观察到填充共混物的伸长率变薄，这对增加 PLA 的应变速率更敏感。二氧化硅的表面改性表现在不同的伸长行为中。事实上，通过在 LLDPE 中加载改性二氧化硅纳米粒子发生了断裂。然而，这种行为的强度对于具有高改性二氧化硅填充量的填充共混物而言显着增加。图形概要