Bangchao Zhong

Thermal Degradation Behaviors of Poly(vinyl chloride)/Halloysite Nanotubes Nanocomposites

Poly(vinyl chloride) (PVC)/halloysite nanotubes (HNTs) nanocomposites were prepared by melt blending. Transmission electron microscopy (TEM) results showed that HNTs were uniformly dispersed in the PVC matrix. The thermal properties of PVC/HNTs nanocomposites were investigated in detail. The apparent activation energies (Ea) were analyzed by means of Kissinger and Flynn-Wall-Ozawa methods. Thermogravimetric analysis results showed that the thermal properties of PVC/HNTs nanocomposites were improved. Cone calorimetry was used to measure the smoke evolution and fire properties. The addition of HNTs led to a remarkable reduction in the smoke production rate, the total smoke production, and the peak heat release rate.

A facile and green preparation of nanosilica-supported antioxidant and its reinforcement and antioxidation effect on styrene-butadiene rubber

ABSTRACT A novel solid-phase method has been proposed to prepare a nanosilica-supported antioxidant by the reaction of nanosilica with 2-mercaptobenzimidazole (MB) and silane coupling agent γ-chloropropyltriethoxysilane. Fourier transform-infrared spectroscopy and other characterization methods confirmed that MB was chemically bonded onto the surface of nanosilica. Silica-s-MB was homogeneously dispersed in a styrene-butadiene rubber (SBR) matrix with strong filler-rubber interaction, leading to enhanced mechanical performance of SBR/silica-s-MB composites compared with SBR/m-silica composites. Based on the results of thermo-oxidation testing of SBR/silica-s-MB and SBR/m-silica/MB composites containing equivalent antioxidant component, silica-s-MB showed better antioxidative efficiency than the corresponding low-molecular-weight MB owing to its lower migration and volatility at high temperature.

Characterization of effects of thermal-oxidative aging on styrene-butadiene rubber/silica composites with vitamin C-lanthanum complex

ABSTRACT A novel rubber antioxidant, vitamin C-lanthanum complex, was prepared and applied in styrene-butadiene rubber (SBR)/silica composites. The anti-aging behavior of SBR/silica composites with vitamin C-lanthanum complex was systematically investigated by mechanical property retention after aging, oxidation induction time, exothermic enthalpies of thermal oxidation, and thermo-oxidative degradation kinetics. The highlight of this work lies in the fact that several thermal analysis techniques were successfully applied to fully evaluate the thermal-oxidative aging of SBR/silica composites and the vitamin C-lanthanum complex was found to endow SBR/silica composites with better protection against aging than commercial antioxidants, which may be beneficial for better characterization of rubber aging and fruitful for the preparation of highly aging-resistant rubber composites, respectively.

Halloysite Tubes as Nanocontainers for Herbicide and Its Controlled Release in Biodegradable Poly(vinyl alcohol)/Starch Film

Commercial herbicide atrazine (AT) was first loaded into the lumen of halloysite nanotubes (HNTs) in the amount of 9 wt %, and then the AT-loaded HNTs (HNTs-AT) were further incorporated into poly(vinyl alcohol)/starch composites (PVA/ST, with the weight ratio of 80/20) to construct a dual drug delivery system. AT loaded in nanotubes displayed much slower release from PVA/ST film in water than free AT; for example, the total release amount of AT from PVA/ST film with loaded AT was only 61% after 96 h, while this value reached 97% in PVA/ST film with free AT. The release behavior of AT from PVA/ST film with HNTs-AT was first dominated by the mechanism of matrix erosion and then by the mechanism of Fickian diffusion. In addition, combining HNTs and PVA/ST blends together in the controlled release of herbicide also reduced its leaching through the soil layer, which would be useful for diminishing the environmental pollution caused by pesticide.

Characterization of Waste Printed Circuit Boards Nonmetals and its Reutilization as Reinforcing Filler in Unsaturated Polyester Resin

Waste printed circuit boards (WPCB) nonmetals were firstly recycled as reinforcing filler in a kind of novel room temperature cured unsaturated polyester (UPE) composites. The compositions and characteristics of WPCB nonmetals were detailly analyzed by SEM, FTIR, TGA and Py-GCMS, and the effects of the content of WPCB nonmetals on the mechanical performance and thermal behaviors of UPE composites were also systematically studied. Results suggested that UPE composites incorporated with WPCB nonmetals at appropriate content showed superior tensile strength, flexural strength and heat distortion temperature than UPE matrix. Based on the analysis of thermal degradation kinetic, the thermal stability of UPE composites were significantly enhanced by the incorporation of WPCB nonmetals. The highlight of this work lies in the fact that high-valued utilization of WPCB nonmetals is realized in room temperature cured UPE matrix, which may not only achieve favorable economic and social benefits, but also open up new opportunities for the preparation of high performance plastic composites.