SYNTHESIS AND CHARACTERIZATION OF A NOVEL ALCOHOL-SOLUBLE POLYORGANOSILOXANE CONTAINING AMINO SIDE GROUPS

A novel alcohol-soluble polyorganosiroxane containing amino side groups, poly[3-(4-aminophenoxy)-aminophenoxy) propylmethylsiloxane] (2), was first prepared by the reduction of nitro groups on 4-nitrophenoxypropyl side chains of poly[3-(4-nitrophenoxy)propylmethylsiloxane] (1). The reaction proceeded easily with nearly 100% conversion. The synthesized alcohol-soluble polymer 2, which has potential application as a precursor for preparing advanced functional polymers, was characterized by FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, VPO and GPC, respectively.

Temporal characteristics of agarwood formation in Aquilaria sinensis after applying whole-tree agarwood-inducing technique

Objective: Agarwood—a resinous wood produced by Aquilaria plants in response to injury or artificial induction—is a valuable medicinal and fragrance resource. Whole-Tree Agarwood-Inducing Technique(Agar-WIT) has been widely used to produce agarwood. However, the time-dependent characteristics of agarwood formation induced by Agar-WIT are yet to be clarified. To promote technologically efficient utilization and upgradation of Agar-WIT, the dynamic process and mechanism of agarwood formation were analyzed for one year.Methods: Agarwood formation percentage, barrier layer microscopic properties, extract levels, compound level, and characteristic chromatograms of agarwood were examined by referring to the Chinese Pharmacopeia(2020 version).Results: Agar-WIT could maintain a high percentage of agarwood formation over one year compared with that of healthy plants. Alcohol-soluble extract and agarotetrol levels showed fluctuating cyclic changes with peaks occurring first during the fifth and sixth months, and subsequently in the 11th month.Aquilaria trees subjected to Agar-WIT treatment for 1–12 months showed significant characteristics of a dynamic agarwood formation process. The barrier layer began to appear in the fourth month after treatment. Alcohol-soluble extractive levels in agarwood formed in the second month, and thereafter,exceeded 10.0%, and agarotetrol in agarwood produced after four months or later, exceeded 0.10%.Conclusion: According to the Chinese Pharmacopoeia, alcohol-soluble extractive levels in agarwood should not be less than 10.0% and agarotetrol level should exceed 0.10%. After four months of Agar-WIT treatment, the formed agarwood theoretically met these standards and was suitable for developed and utilization. However, the optimal harvest time was found to be the 11th month, followed by the sixth month after Agar-WIT treatment. Therefore, Agar-WIT resulted in swift agarwood formation and stable accumulation of alcohol-soluble extracts and agarotetrol. Thus, this method is efficient for large-scale cultivation of Aquilaria sinensis to produce agarwood and provide raw materials for the agarwood medicinal industry.

Highly efficient pure white polymer light-emitting devices based on poly(N-vinylcarbazole) doped with blue and red phosphorescent dyes

Efficient white-polymer-light-emitting devices (WPLEDs) have been fabricated with a single emitting layer containing a hole-transporting host polymer,poly(N-vinylcarbzole),and an electron-transporting auxiliary,1,3-bis[(4-tert-butylphenyl)-1,3,4-oxadiazolyl]-phenylene,codoped with two phosphorescent dyes:Iridium(III)bis (2-(4,6-difluorophenyl)-pyridinato-N,C2') picolinate (FIrpic) and home-made Ir-G2 for blue and red emission,respectively.With the structure of ITO/PEDOT:PSS 4083(40 nm)/emission layer(80 nm)/Ba(4 nm)/Al(120 nm),the device showed a maximal luminous efficiency (LE) of 13.5 cd A-1(corresponding to an external quantum efficiency (EQE) of 6.8%),and a peak power efficiency (PE) of 6.5 lm W-1 at 6.0 V.Meanwhile,the device exhibited pure white emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.34,0.35) at a current density of 12 mA cm-2,which is very close to the equi-energy white point with CIE coordinates of (0.33,0.33).The device performance can be further optimized when more balanced hole/electron injection is achieved by incorporating a lower conducting type anode buffer layer (PEDOT:PSS) and incorporating poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorenene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) as an electron injection layer at the cathode.The optimized device showed an LE of 24.6 cd A-1 (with an EQE of 14.1%),while the peak power efficiency reached 12.66 lm W-1.Moreover,the WPLEDs showed good electroluminescence (EL) stability over a wide range of operating current density and luminance.