Vulcanization Kinetics of Starch Xanthate /Natural Rubber Composite

The starch xanthate/natural rubber (SX/NR) composite was prepared by directly mixing and co-coagulating NR latex and the modified starch paste with carbon bisulfide. The vulcanization kinetics of NR and SX/NR composite were investigated by using a rubber process analysis (RPA). The mechanism of SX/NR composite vulcanization was similar to that of pure NR. The values t0and tdisof XS/NR composite were shorter than that of NR, and the activation energy E1for the induction period was smaller. The activation energies E2and E3for the curing period were smaller than that of NR.

Synthesis of Lignin-Based Dithiocarbamate and its Performance in Pb2+ Removal

Lignin-based dithiocarbamate (LBDTC) was prepared from lignin, formaldehyde, triethylene tetramine (TETA), carbon bisulfide and sodium hydroxide. The structure of LBDTC was characterized by FTIR and elementary analysis, and its removal performances towards Pb2+ were investigated. The results show that LBDTC is more effective than sodium triethylenetetramine-multidithiocarbamate (TETAMDT) prepared according to the same molar ratios of TETA, CS2, and NaOH and xanthation conditions used during LBDTC synthesis and much more effective than lignin for removing Pb2+. It was observed that LBDTC could effectively reduce 100 mg/L Pb2+ in wastewater to 0.05 mg/L, which is far lower than the discharge limit of 1.0 mg/L. It was also observed that LBDTC has a wide suitable pH range of 4.9-12.5. This can overcome the drawback of narrow pH scopes observed for traditional precipitation methods.

Self-Supporting Honeycomb Films of Polyphenylene Oxide Fabrication and Characterization

The PPO films with ordered structures have many potential applications in electronics, optics, separation, etc. Its self-supporting film with regular pores is prepared by evaporating the polyphenylene oxide (PPO) solution in carbon bisulfide under humid ambience. It is demonstrated that the nucleation, growth and ordered packing of water droplets condensed on the PPO solution layer as templates in the process are crutial for high-quality honeycomb films. The humidity, concentration, spreading volume of the PPO solution and the direction of airflow have great impact on the pore size, regularity of the film and so on, which are clarified by experiments.