Shuang Li,Yazhen Wang,Liqun Ma,Xueze Zhang,Shaobo Dong,Li Liu,Xilai Zhou,Chenglong Wang,Zhen Shi
The reverse atom transfer radical polymerization (RATRP) of acrylonitrile (AN) was carried out in N, N-dimethylformamide (DMF) with AIBN as initiator, FeCl3•6H2O/triphenylphosphine (PPh3) and FeCl3•6H2O/pentamethyldle-thylenetrlamlne (PMDETA) as catalytic systems, respectively. Effect of reaction time and initiator concentration on polymerization rate, molecular weight and molecular weight distribution were investigated in detail. The Fourier transform infrared spectrometer (FTIR) and 1H nuclear magnetic resonance spectroscopy (1HNMR) were employed to analyze the chain end of the PAN. Gel permeation chromatography (GPC) was applied to measure the molecular weight and polydispersity index (PDI) of PAN. The polymerization demonstrated a typical pseudo first-order kinetics characteristics as evidenced by the number-average molecular weights (Mn) increasing linearly with monomer conversion; the Mn decreasing with the increasing of the initiator concentration. Meanwhile, the low PDI value (<1.2) indicated the controllability of polymerization.
Weining Sun,Xiaofeng Lu,Yan Tong,Junyu Lei,Guangdi Nie,Ce Wang
In this report, a palladium/polypyrrole/polyacrylonitrile (Pd/PPy/PAN) composite nanofiber membranes was synthesized by a one-pot redox polymerization process between pyrrole monomers and Na2PdCl4 in the presence of electrospun PAN nanofibers, without the introduction of any other surfactants or reductants. The as-prepared Pd/PPy/PAN nanofiber membrane exhibited good catalytic performance towards hydrogen generation from the hydrolysis of ammonia borane (AB). The apparent activation energy (Ea) was calculated to be about 33.5 kJ mol−1. In addition, the Pd nanoparticles (Pd NPs) were encapsulated in PPy layers on the surface of the PAN nanofibers, enabling the catalyst to be stable against poisoning and easily separated from the suspension system. The catalytic activity does not weaken after five cycles. This study indicated that the obtained Pd/PPy/PAN composite nanofiber membrane could be applied as an alternative in exploring new catalysts for hydrogen generation, as hydrogen is an important fuel as a clean power source.
A novel polymer of intrinsic microporosity , acyl chloride-functionalized polymer of intrinsic microporosity (PIM-COCl), was obtained by hydrolysis under alkaline conditions and acylation in thionyl chloride of PIM-1. PIM-COCl is soluble in common organic solvents , and it is used for the first time for organic solvent nanofiltration (OSN). The acyl chloride groups in PIM-COCl can be further cross-linked with an amine-functionalized polyacrylonitrile (APAN) ultrafiltration membrane to form an interconnected layer, which shrinks pore size and provides better structural stability and selectivity. The PIM-COCl composite membranes exhibit high rejection and alcohol flux during OSN. Compared with the reported PIM OSN membranes , [email protected] exhibits higher rejection for crystal violet (408 g mol −1 , over 94%) in ethanol and several times higher alcohol flux. The membrane shows outstanding stability in ethanol for 14 days. PIM provides a microporous structure, while the interconnected layer maintains this structure in organic solvents via hydrogen bonding , electrostatic interactions and covalent cross-linking. Other PIMs can readily undergo acyl chloride functionalization, which provides them with high reactivity towards amine groups to form stable interconnected layers. This work offers new strategies for the design and preparation of high performance OSN membranes .
危险品化学品经营许可证（带存储）