ε‐Branched Flexible Side Chain Substituted Diketopyrrolopyrrole‐Containing Polymers Designed for High Hole and Electron Mobilities

Based on the integrated consideration and engineering of both conjugated backbones and flexible side chains, solution‐processable polymeric semiconductors consisting of a diketopyrrolopyrrole (DPP) backbone and a finely modulated branching side chain (ε‐branched chain) are reported. The subtle change in the branching point from the backbone alters the π?π stacking and the lamellar distances between polymer backbones, which has a significant influence on the charge‐transport properties and in turn the performances of field‐effect transistors (FETs). In addition to their excellent electron mobilities (up to 2.25 cm² V^?1 s^?1), ultra‐high hole mobilities (up to 12.25 cm² V^?1 s^?1) with an on/off ratio (I_on/I_off) of at least 10⁶ are achieved in the FETs fabricated using the polymers. The developed polymers exhibit extraordinarily high electrical performance with both hole and electron mobilities superior to that of unipolar amorphous silicon.     

Long-term impact of anaerobic reaction time on the performance and granular characteristics of granular denitrifying biological phosphorus removal systems

Removal of nitrogen and phosphorus (P) from wastewater is successfully and widely practiced in systems employing both granular sludge technology and enhanced biological P removal (EBPR) processes; however, the key parameter, anaerobic reaction time (AnRT), has not been thoroughly investigated. Successful EBPR is highly dependent on an appropriate AnRT, which induces carbon and polyphosphate metabolism by phosphorus accumulating organisms (PAOs). Therefore, the long-term impact of AnRT on denitrifying P removal performance and granular characteristics was investigated in three identical granular sludge sequencing batch reactors with AnRTs of 90 (R1), 120 (R2) and 150 min (R3). The microbial community structures and anaerobic stoichiometric parameters related to various AnRTs were monitored over time. Free nitrite acid (FNA) accumulation (e.g., 0.0008–0.0016 mg HNO₂–N/L) occurred frequently owing to incomplete denitrification in the adaptation period, especially in R3, which influenced the anaerobic/anoxic intracellular intermediate metabolites and activities of intracellular enzymes negatively, resulting in lower levels of poly-P and reduced activity of polyphosphate kinase. As a result, the Accumulibacter-PAOs population decreased from 51 ± 2.5% to 43 ± 2.1% when AnRT was extended from 90 to 150 min, leading to decreased denitrifying P removal performance. Additionally, frequent exposure of microorganisms to the FNA accumulation and anaerobic endogenous conditions in excess AnRT cases (e.g., 150 min) stimulated increased extracellular polymeric substances (EPS) production by microorganisms, resulting in enhanced granular formation and larger granules (size of 0.6–1.2 mm), but decreasing anaerobic PHA synthesis and glycogen hydrolysis. Phosphorus removal capacity was mediated to some extent by EPS adsorption in granular sludge systems that possessed more EPS, longer AnRT and relatively higher GAOs.     

A review on Zeolite-Reinforced Polymeric Membranes: Salient Features and Applications

Various types of synthetic polymeric membranes have been fabricated for separation purposes in industry/laboratory. Zeolite is ceramic-based material and well known for its antiwear resistance and high mechanical strength. Mixed matrix membranes are the latest membrane technology constituting inorganic nanoparticle phase and organic polymer phase. The review represents various types and applications of zeolite-reinforced polymeric membranes. Consequently, fabrication procedure and working principle of zeolite-reinforced mixed matrix (polyimide, polysulfone, polycarbonate) membranes have been discussed. The significant relevance of polymer/zeolite membranes is in water purification, medical, catalytic, and gas separation industries. Improvement in polymeric membrane properties has been observed through incorporation of zeolite filler.     

Application of Gurson Model for Evaluation of Density‐Dependent Mechanical Behavior of Polyurethane Foam: Comparative Study on Explicit and Implicit Method

Recently, liquefied natural gas (LNG) is a focus of interest around the world for several reasons, and LNG cargo containment systems (CCS) increase in quality to prevent loss of LNG during shipping. For insulation of CCS, polyurethane foam (PUF), an outstanding insulation material, is commonly used. However, until now, although its mechanical properties are relatively good, the material is not considered as a structural member under compressive loading, principal load direction in CCS. Moreover, as PUF is a porous material by mixing and foaming, its mechanical properties depend on voids, which is a dominant parameter for density. Therefore, in the present study, nonlinear behavior of PUF is described using Gurson model with a novel technique, i.e., an acceleration factor. The model expresses the behavior through the volume fraction of voids with consideration of the density effect to evaluate structural performance using user‐defined material subroutine with explicit and implicit methods.

     

BMI改性丁腈橡胶在聚合物基摩擦材料中应用研究

采用N-N'-4,4'-二苯甲烷型双马来酰亚胺(BMI)改性丁腈橡胶,并将其增韧的酚醛树脂应用于聚合物基摩擦材料中.通过对同一摩擦材料配方体系条件下,采用不同的改性树脂得到的摩擦材料的物理力学性能,如冲击强度、吸油、吸水性能及材料的摩擦磨损性能的表征,对比研究了采用不同BMI改性工艺后摩擦材料的摩擦磨损性能,指出以8%BMI改性的制品较为优良.     

聚羧酸减水剂改性聚合物无机基复合材料防腐性能研究

将不同含量的聚羧酸减水剂改性聚合物无机基复合材料涂覆至打磨光滑的马口铁板上制成样板,分别对样板进行常温养护、紫外老化和盐水浸泡等试验,测试其附着力等级、耐冲击性能和抗弯折性能,结果表明:聚羧酸减水剂改性聚合物无机基复合材料在各腐蚀试验下力学性能均有不同幅度的改善,且减水剂添加量在0.9%~1.2%的范围内减水效果最好,所得材料的性能也最优。     

角蛋白与聚合硫酸铁复配体系处理选煤废水的研究

采用单因素实验方法,以选煤废水为研究对象,将鸡毛角蛋白助剂与聚合硫酸铁复配体系用于选煤废水处理,研究复配体系对选煤废水的处理效果。结果表明:复配体系的最佳配置为鸡毛角蛋白助剂0.2 g/L,聚合硫酸铁0.025 g/L,且该复配体系实现了在碱性条件下高效处理选煤废水。该复配体系处理选煤废水的最佳工艺条件为:室温下,选煤废水在pH值为7~8的条件下,投加角蛋白复配体系并搅拌,搅拌速度为120 r/min,反应后沉降30 min,此时,SS(固体悬浮物)去除率达到92%以上。     

Terpolymers as precursors for CuO nanoparticles synthesis

This work describes the synthesis of terpolymers of aniline, diphenylamine, and o‐anthranilic acid (PANIDPAA) by 1 : 1 : 1 molar ratio of the respective monomers doped by different concentration of copper ions via in situ chemical terpolymerization. The results are justified by measuring spectral characteristics namely, UV‐vis absorption spectra, FTIR, and TGA. Calcining these PANIDPAA terpolymers doped by copper at temperatures in the range of 700°C led to the formation of CuO nanoparticles in the nanoscale by thermal decomposition in air directly. The stages of decompositions and the calcination temperature of the precursors have been determined from thermal analysis data sheet. The obtained CuO nanoparticles have been characterized by X‐ray diffraction and transmission electron microscope (TEM). TEM showed a particle size less than 40 nm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41150.     

Enhanced gas separation properties of metal organic frameworks/polyetherimide mixed matrix membranes

Metal organic frameworks (MOFs) are supposed to be ideal additives for mixed matrix membranes (MMMs). In this article one kind of MOFs, Cu₃(BTC)₂, is synthesized, then directly incorporated into a model polymer (Ultem®1000) using N,N‐dimethylacetamide as solvent. Cu₃(BTC)₂ particles are uniformly dispersed and there are no interfacial defects in the prepared MMMs when Cu₃(BTC)₂ loading is not more than 35 wt %, seen in SEM images. Pure gas permeation tests show that gas permeability increases obviously with Cu₃(BTC)₂ loading increase, while ideal selectivities of CO₂/N₂ and CO₂/CH₄ are almost unchanged. For MMM with the best separation property, CO₂ permeability increases about 2.6 times and CO₂/N₂ selectivity remains almost unchanged. Results about gas diffusivity and solubility indicate that gas diffusivity and solubility make contribution to gas permeability increase at the same time but in different ways. Gas permeation properties of MMMs are well predicted by Maxwell or Bruggeman model. © 2014 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40719.