The Influence of Epitaxial Crystallization on the Mechanical Properties of Polyamide 66/Reduced Graphene Oxide Nanocomposite Injection Bar

Polyamide 66 (PA66) was chosen as the representative of hydrophilic polymers, to investigate the influence of epitaxial crystals in semi-crystalline polymers/reduced graphene oxide nanocomposite injection-molding bars. A differential scanning calorimeter was used, and the two-dimensional wide-angle X-ray diffraction technique, as well as the two-dimensional small angle X-ray scattering technique, were used to research the crystallization behavior in PA66/RGO nanocomposites. The results indicated that RGO was an effective nucleation agent for PA66. The presence of RGO could enhance the orientation degree of the PA66 crystals and did not influence the crystal structure of the PA66. The non-epitaxial crystals and the epitaxial crystals existed in PA66/RGO nanocomposites. The size of epitaxial crystals was much greater than that of the non-epitaxial crystals. Tensile test results showed that the presence of fewer epitaxial crystals can improve the mechanical properties of a polymer

Ultra-strong gel-spun ultra-high molecular weight polyethylene fibers filled with chitin nanocrystals

Ultra-high molecular weight polyethylene (UHMWPE)/chitin nanocrystals (CNC) and UHMWPE/acetylated chitin nanocrystals (ACNC) fibers were prepared. The addition of CNC and ACNC significantly enhanced the ultimate tensile strength and Young's modulus of the UHMWPE fibers matrix. Compared with that of pure UHMWPE fibers, the ultimate tensile strength and Young's modulus of UHMWPE/CNC fibers are increased by about 14.5% and 17.0%, respectively, with the incorporation of 1.0 wt% CNC. Furthermore, with the addition of 1.0 wt% ACNC, the ultimate tensile strength and Young's modulus of UHMWPE/ACNC fibers are improved by 15.8% and 21.3%, respectively. To understand the mechanism of CNC and ACNC reinforcing UHMWPE fibers, the thermal, crystallinity, orientation and shish structure of pure UHMWPE fibers, UHMWPE/CNC fibers, and UHMWPE/ACNC fibers were determined by employing a differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS) analyses

Production of a gadolinium-loaded liquid scintillator for the Daya Bay reactor neutrino experiment

We report on the production and characterization of liquid scintillators for the detection of electron antineutrinos by the Daya Bay reactor neutrino experiment. A 185 tons of gadolinium-loaded (0.1% by mass) liquid scintillator (Gd-LS) and a 200 tons of unloaded liquid scintillator (LS) were successfully produced from a linear-alkylbenzene (LAB) solvent in 6 months. The scintillator properties, the production and purification systems, and the quality assurance and control (QA/QC) procedures are described. © 2014 Elsevier B.V