Design and preparation of high-aspect-ratio zinc borate whiskers and their effects on mechanical properties of PP nanocomposite

Well-dispersed, high-aspect-ratio 4ZnO·B 2 O 3 ·H 2 O whiskers (4ZnO·B 2 O 3 ·H 2 O HARw ) were synthesized by a facile hydrothermal method with the aid of ZnSO 4 ·7H 2 O. The formation mechanism was investigated, and the results showed that Zn 2+ and SO 2− 4 ions played a crucial role in the control of 4ZnO·B 2 O 3 ·H 2 O HARw extended along [010] direction. X-ray diffraction (XRD) analysis, high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG)-differential scanning calorimetry (DSC) results confirmed that the powder was 4ZnO·B 2 O 3 ·H 2 O. Scanning electron microscopy (SEM) and TEM showed that the average aspect ratio of the product was about 100. Nanocomposites of surface-modified 4ZnO·B 2 O 3 ·H 2 O SM-HARw /PP were prepared and their mechanical properties measured. The results suggested that the mechanical properties of 4ZnO·B 2 O 3 ·H 2 O SM-HARw /PP composites were superior to composites made with low-aspect-ratio whiskers (4ZnO·B 2 O 3 ·H 2 O SM-LARw ), which displayed poorer mechanical properties even at low addition.