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Xing Q.,CAS Beijing National Laboratory for Molecular | Zhang X.,Beijing Institute of Fashion Technology | Dong X.,CAS Beijing National Laboratory for Molecular | Liu G.,CAS Beijing National Laboratory for Molecular | Wang D.,CAS Beijing National Laboratory for Molecular
Polymer | Year: 2012

Two kinds of low molecular weight aliphatic amides, N, N′-ethylenebis (12-hydroxystearamide) (EBH) and N, N′-ethylenebisstearamide (EBSA), have been selected in present study to mediate the crystallization behavior of poly (L-lactic acid) (PLLA). The results showed that the crystallization rate of PLLA was significantly improved with the addition of EBH and EBSA, and EBH presented a stronger nucleating efficiency. The correlation between the variation of chain conformation during the early stages of isothermal crystallization and the enhancement of crystallization rate for pure PLLA and its mixtures was investigated by time-resolved FTIR. The formation of interchain conformational-ordered structure and intrachain 10 3 helix structure for amide-doped PLLA preceded that for pure PLLA, suggesting a stimulatory nucleating effect of EBH and EBSA. In the case of PLLA/EBH, the interchain interactions of -(COC + CH 3) and -CH 3 groups were faster than the -(CH 3+CC) intrachain interactions, while the interchain interactions and the intrachain 10 3 helix formation were nearly synchronous for PLLA/EBSA. The hydrogen bond interaction between hydroxyl groups in EBH and the carbonyl groups in PLLA was proposed to be an important factor influencing the conformation variation during isothermal crystallization of PLLA. © 2012 Elsevier Ltd. All rights reserved.

Liang P.,Tsinghua University | Yuan L.,Tsinghua University | Yang X.,Desert Research Institute | Zhou S.,Beijing Institute of Fashion Technology | Huang X.,Tsinghua University
Water Research | Year: 2013

A capacitive deionization (CDI) cell was built with electrodes made of an inexpensive commercial activated carbon fiber (ACF), and then modified by incorporating ion-exchangers into the cell compartment. Three modified CDI designs were tested: MCDI - a CDI with electrodes covered by ion-exchange membranes (IEMs) of the same polarity, FCDI - a CDI with electrodes covered by ion-exchange felts (IEFs), and R-MCDI - an MCDI with cell chamber packed with ion-exchange resin (IER) granules. The cell was operated in the batch reactor mode with an initial salt concentration of 1000 mg/L NaCl, a typical level of domestic wastewater. The desalination tests involved investigations of two consecutive operation stages of CDIs: electrical adsorption (at an applied voltage of 1.2 V) and desorption [including short circuit (SC) desorption and discharge (DC) desorption]. The R-MCDI showed the highest electric adsorption as measured in the present study by desalination rate [670 ± 20 mg/(L h)] and salt removal efficiency (90 ± 1%) at 60 min, followed by the MCDI [440 ± 15 mg/(L h) and 60 ± 2%, respectively]. The superior desalination performance of the R-MCDI over other designs was also affirmed by its highest charge efficiency (110 ± 7%) and fastest desorption rates at both the SC [1960 ± 15 mg/(L·h)] and DC [3000 ± 20 mg/(L·h)] modes. The desalination rate and salt removal efficiency of the R-MCDI increased from ~270 mg/(L h) and 83% to ~650 mg/(L h) and 98% respectively when the applied voltage increased from 0.6 V to 1.4 V, while decreased slightly when lowering the salt water flow rate that fed into the cell. The packing of IER granules in the R-MCDI provided additional surface area for ions transfer; meanwhile, according to the results of electrochemical impedance spectroscopy (EIS) analysis, it substantially lower down the R-MCDI's ohmic resistance, resulting in improved desalination performance. © 2013 Elsevier Ltd.

Liu G.,CAS Beijing National Laboratory for Molecular | Zhang X.,Beijing Institute of Fashion Technology | Wang D.,CAS Beijing National Laboratory for Molecular
Advanced Materials | Year: 2014

Poly(lactic acid) (PLA) is one of the most promising alternatives for petrochemical-based plastics. Crystallization mediation provides the simplest and most practical approach for enhancing the properties of PLA. Here, recent advances in understanding the relationship between crystalline structure and properties of PLA are summarized. Methods for manipulating crystallization towards high-performance PLA materials are introduced. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen Y.,Beijing Institute of Fashion Technology
Wool Textile Journal | Year: 2016

Waste Textiles produced annually in Japan in terms of total and per capita are far less than the United States, and the recycling rate of waste textles is higher than that of the United States. To some extent, this is due to less consumption of Japanese consumers, on the other hand, it is related to multiple recycling ways in Japan. For different waste textiles, there are different recycling methods. Clothes which can be worn directly are exported or sold domestically. Cotton clothes are processed into machine wipers or bio-ethanol. Specific chemical fiber clothes are chemically reprocessed into new fiber and then to clothes. Mixed fiber clothes are produced into insulation materials or building materials after opening. The remaining is burnt to recycle the energy. Through a variety of recycling, the Japanese companies utilize waste textiles effectively.

Lei M.,Beijing University of Chemical Technology | Zhang W.,Beijing University of Chemical Technology | Chen Y.,Beijing University of Chemical Technology | Tang Y.,Beijing Institute of Fashion Technology
Organometallics | Year: 2010

In this work, H2 activation processes in hydrogenation of ketones catalyzed by late transition metal-ligand bifunctional catalysts have been studied using the DFT method. For systems A (RuH2diphosephine/ diamine complex) and B (Ru-η5-Cp*-l,2-diamine complex), the dihydrogen activation process in neutral and basic conditions (path 1) consisted of two steps: H2 coordination and H-H cleavage. However, dihydrogen activations catalyzed by complexes C-F (Ru- η6-arene and Rh/ Ir-cyclopentadiene complexes) along path 1 consist of only H-H cleavage due to the absence of H2 coordination. Thus, systems C-F have higher energy barriers (△G >27 kcal/mol) for dihydrogen activation than systems A and B. However, for systems C-F under acidic conditions, dihydrogen activation (path 2) consists of the two steps involving H2 coordination; thus the dihydrogen activation barriers decrease greatly, resulting in an easy splitting of H2. These results agree well with experiments. In the conversion from transfer hydrogenation to H2 hydrogenation for C-F, the protonation of 16e complex MN C-F changes the N2-M1 -Y3 (Y = N or O) delocalized jr-bond into a M1-Y3 localized jr-bond. Therefore, the 16e complexes, which can provide a vacant site for H2 coordination, tend to perform H2 hydrogenation. © 2010 American Chemical Society.

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