No abstract

A thermotropic liquid crystalline polymer (TLCP) was synthesized from 4, 4'-Oxobisbenzoic acid and methylhydroquinone by low-temperature solution polycondensation. Nanocomposites of TLCP with the content of MWNTs from 0 wt% to 10 wt% were prepared by in situ polymerization. Scanning electron microscopy images showed that the MWNTs were well-separated in the TLCP matrix. Differential scanning calorimetry, thermogravimetric analyzer, X-ray diffraction, and polarized optical microscopy were used to investigate the thermal behavior, crystalline structure and liquid crystalline properties of the pure TLCP and TLCP/MWNT nanocomposites. The thermogravimetric analyses indicated that a small amount of MWNTs could improve the thermal stability of TLCP matrix. Furthermore, the result of differential scanning calorimetry demonstrated that both melt transition temperatures and isotropic transition temperatures of the hybrids were enhanced. Our study provided a design guide for CNT-filled TLCP composites which could be favorable for industrial use.

Leaf blight disease (LBD) caused by Pantoea agglomerans is a newly emerged oat disease in China that causes great economic and yield losses of oat production. Laboratory and field experiments were conducted to evaluate the efficacy of 13 antimicrobial agents against P. agglomerans and recommend agents with better control efficacy for use. The antibacterial potential of four concentrations of each agent was evaluated under in vitro conditions. Zhongshengmycin and ethylicin were the most effective in inhibiting the growth of P. agglomerans; their bacteriostatic rates (85.0% and 84.8%, respectively) were higher while EC50 lower (0.31 and 0.90, respectively) than other agents. The greenhouse and field experiment suggested that the greatest fresh weight per plant (57.26 g and 57.93 g), forage yield (22.53 t/ha and 22.21 t/ha) and control efficacy (>75%) were obtained after spraying twice with zhongshengmycin or ethylicin in the LBD occurrence phase, with lower yields and control by kasugamycin + dicopper chloride trihydroxide, kasugamycin + oxine copper, benziothiazolinone, copper hydroxide, phenanthrenecarboxylicacid, copper, picoxystrobin, chloroisobromine cyanuric acid, oxathiapiprolin or azoxystrobin. Foliar application of zhongshengmycin or ethylicin can therefore be used for the effective management of LBD of oat.