Moisture sorption characteristics of waste activated sludge

Nowadays the treatment of activated sludge often includes a thermal drying step. Data such as water vapour sorption isotherms and heat of sorption are required for good design and control of the drying processes. An equilibrium method was used to measure these data on domestic activated sludge, between 39 °C and 80 °C. The experimental investigation indicated that the nature of the sludge and its evolution (bulking sludge, anaerobic storage) do not affect the sorption isotherms. Experimental data were fitted to different well‐known models; the Oswin relationship gave the better fit. Based on sorption data the heat of sorption as a function of moisture content was determined. © 2001 Society of Chemical Industry     

PP/PE共混物的红外光谱分析

采用傅立叶变换红外光谱法对PP和PE的共混物进行了分析。结果表明 :用红外光谱法可以测定PP/PE共混物中PE的含量和结晶度 ;PP与质量分数为 0～ 10 %的PE熔融共混后 ,其红外光谱未见明显偏离两者各自的特征 ,但是差谱结果表明PE与PP存在一定的相互作用。     

Ternary blend nanofibres of poly(lactic acid), polycaprolactone and cellulose acetate butyrate for skin tissue scaffolds: influence of blend ratio and polycaprolactone molecular mass on miscibility,morphology, crystallinity and thermal properties

Ternary blends of poly(lactic acid) (PLA), polycaprolactone (PCL) and cellulose acetate butyrate (CAB) were fabricated into the form of electrospun nanofibres targeted for skin tissue scaffolds. The effects of blend ratio and molecular mass of PCL (PCL1 and PCL2) on morphology, miscibility, crystallinity, thermal properties, surface hydrophilicity and cell culture of the nanofibres were investigated. Blends with high PLA loading (80/10/10 PLA/PCL/CAB) gave fibres with a smooth surface, owing to the enhanced miscibility between the polymer chains from the presence of CAB, which acts as compatibilizer. In contrast, blends with high PCL loading were immiscible, which led to beads during the electrospinning process. The increased molecular mass of PCL2 produced smoother fibres than low‐molecular‐mass PCL1. The XRD patterns of blends of PLA/PCL1/CAB and PLA/PCL2/CAB were similar to one another, in which the high‐crystallinity peaks of PCL seen for 20/70/10 blends were very small for 50/40/10 blends and much less prevalent for 80/10/10 blends. Better fibre formation (80/10/10 > 50/40/10 > 20/70/10) with less crystallinity occurs in well‐formed fibres. Selected blends of PLA/PCL/CAB promoted growth of NIH/3T3 fibroblast cells, demonstrating that our novel biocompatible ternary blend nanofibrous scaffolds have potential in skin tissue repair applications. In addition, this work helps in the design and understanding of the factors that control the properties of nanofibrous PLA/PCL/CAB scaffolds. © 2017 Society of Chemical Industry     

乙基纤维素与聚苯乙烯共混体系的溶致液晶性研究

在EC/PS共混体系中,EC的临界浓度与共混组成无关,都是30％。组分在溶液中发生微观相分离。无论组成比多少,在EC相畴中均能形成滴状织构。观察到有混合组成的第三种相畴,它的存在有助于增加相溶性。在大多数组成比的共混物的EC相中,剪切时均能观察到条带织构。     

Moisture sorption isotherms of two varieties of millet

Moisture sorption isotherms of EX-BORNO and SOSAT C88 millets at temperature range of 30–70 °C and water activity range of 0.07–0.98 were determined using the static gravimetric method. The sorption isotherms of both millet varieties decreased with increasing temperature, exhibited type II behaviour according to BET classification and hysteresis having loop size increasing with increasing temperature. This is as a result of the hard nature of the millet varieties. The moisture sorption and the data fitted well with Modified Henderson, Modified Halsey, Modified Oswin and Modified GAB models. The constants of the equations used in fitting were determined by non-linear regression analysis when the models were compared using the standard error of estimate, mean relative percent deviation, fraction explained variation and residual plots. The Modified Oswin model gave the best fit for the whole set of data. The study has provided information and data useful in large scale drying and processing of millet which have remained at the traditional level despite the importance of the drought resistance crop in poverty alleviation.     

Morphology and thermal properties of PPS/ABS blend systems

In this study the PPS/ABS blend system was investigated in order to collectively identify the relationship among blend morphology, chemical compatibilization, and thermal property. The ABS resin was chemically modified by the incorporation of maleic anhydride through reactive extrusion for enhanced compatibilization, and ABS/PPS and the modified ABS/PPS blends were prepared by a twin‐screw extruder. The effect of chemical modification of ABS on the morphological, mechanical, and thermal properties of the resulting blend was examined. A strong chemical interaction between PPS and MABS was observed by optical microscopy, scanning electron microscopy, and FTIR. The PPS/MABS blend showed a single glass‐transition temperature in dynamic mechanical analysis, demonstrating pseudo‐homogeneous phase morphology induced by chemical compatibilization. The PPS/MABS blend also exhibited an enhanced thermal stability and heat distortion temperature compared with the PPS/ABS blend. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 661–665, 2003     

PA6/LDPE/PE-g-MAH共混纳米纤维的制备及结构研究

采用共混海岛纺丝法制备聚酰胺6/低密度聚乙烯/聚乙烯接枝马来酸酐(PA6/LDPE/PE-g-MAH)共混纤维,溶解剥离出LDPE基体相,可制备出PA6纳米纤维;研究了共混物的组成和纺丝条件对共混纤维的相结构、结晶、力学性能及PA6纳米纤维直径的影响。结果表明:随着共混物中PA6分散相含量增加,PA6纳米纤维的直径逐渐增大;PA6质量分数从30%增加至60%时,PA6纳米纤维平均直径由107 nm增至149nm;PA6质量分数为70%时,由于相逆转无法得到PA6纳米纤维;在PA6质量分数为55%条件下,提高拉伸倍数,PA6纳米纤维的直径进一步降低,且结晶度、力学性能增加。     

Morphological,thermal, and mechanical properties of polypropylene/polycarbonate blend

This work deals with the effect of compatibilizer on the morphological, thermal, rheological, and mechanical properties of polypropylene/polycarbonate (PP/ PC) blends. The blends, containing between 0 to 30 vol % of polycarbonate and a compatibilizer, were prepared by means of a twin-screw extruder. The compatibilizer was produced by grafting glycidyl methacrylate (GMA) onto polypropylene in the molten state. Blend morphologies were controlled by adding PP-g-GMA as compatibilizer during melt processing, thus changing dispersion and interfacial adhesion of the polycarbonate phase. With PP-g-GMA, volume fractions increased from 2.5 to 20, and much finer dispersions of discrete polycarbonate phase with average domain sizes decreased from 35 to 3 μm were obtained. The WAXD spectra showed that the crystal structure of neat PP was different from that in blends. The DSC results suggested that the degree of crystallization of PP in blends decreased as PC content and compatibilizer increased. The mechanical properties significantly changed after addition of PP-g-GMA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1857–1863, 1997     

涤棉织物化学回收工艺研究

以废旧涤棉织物为原料,乙二醇(EG)为醇解剂,通过改变醇解时间、醇解温度、EG/废旧涤棉织物中聚对苯二甲酸乙二醇酯(PET)质量比(mEG/mPET)、催化剂种类及用量等研究了蓬松态下废旧涤棉织物的醇解工艺,以及醇解过程对涤棉织物中棉纤维性能的影响。结果表明:随着醇解时间、醇解温度的提高,mEG/mPET的增大,涤棉织物的醇解程度增大,各参数达到一定程度后醇解程度基本不变;最佳醇解工艺为涤棉织物中mEG/mPET为2/1,催化剂用量为涤棉织物中PET质量的0.30%,醇解温度196℃,醇解时间1 h;在乙酸锌、碳酸钠、乙酸钾、氯化镁4种催化剂中,碳酸钠综合催化效果最佳;经醇解过程后涤棉织物中棉纤维表面变得粗糙,力学性能有较大下降。     

The characterization of prepared organoclay materials (DDMA) and gas sorption of chlorobenzene

In this paper, adsorptive performance of Tunisian natural clay materials has been investigated as a potential adsorbent for Volatile Organic Compounds (VOCs). The materials used were taken from Aleg and Douiret formations in the south of Tunisia. Organoclay materials (OC) were prepared by intercalating didodecyldimethyl ammonium bromide on clay materials. This intercalation allowed the improvement of the porous texture of the studied materials. The adsorption isotherms showed that the intercalation of the didodecyldimethyl ammonium bromide on clay materials improved their adsorption capacities of chlorobenzene with an adsorption capacity up to 375 mg g⁻¹ for calcined modified clay of Douiret.     

Alkaline dyeing of polyester and polyester/cotton blend fabrics using sodium edetate

An alkaline dyeing of polyester with an alkali‐stable disperse dye, Dianix® Scarlet AD‐RG, was developed using sodium edetate as an alkaline buffering agent. The results obtained indicate the suitability of using sodium edetate for alkaline dyeing of polyester when compared with the control alkaline dyeing using Dianix AD system. Selected mono and bifunctional reactive dyes were used in combination with the alkali‐stable disperse dye for dyeing of polyester/cotton blend. Different dyeing methods for cotton and polyester/cotton blend fabrics using sodium edetate were evaluated in comparison with their respective control alkaline dyeing methods. The results of using sodium edetate in one‐bath two‐stage and two‐bath dyeing of polyester/cotton blend were comparable with that of the control dyeing method. Particularly, no change in the leveling and fastness properties was evaluated for all samples irrespective of the dyeing method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

CTMAB-膨润土对苯酚等污染物的吸附特征研究

用溴化十六烷基三甲铵(CTMAB)制得有机膨润土,并研究了CTMAB-膨润土对水中硝基苯酚、苯酚、苯胺的吸附特征和适宜条件。结果表明,CTMAB-膨润土对水溶液中上述3种有机污染物具有较强的吸附能力,吸附能力与各种污染物本身的辛醇-水分配系数有关,去除率随着有机膨润土投加量的增加而增加。在较低浓度范围内,有机膨润土对上述3种有机物的吸附等温线呈线性,表明分配模式是主要的吸附形式;而在高浓度范围内,有机膨润土对上述3种有机物的吸附等温线则呈现一定的非线性特征。     

Extraction,identification and sorption studies of dyes from madder on wool

Since the last decade, the application of natural dyes on textile materials is gaining popularity all over the world, possibly because of increasing awareness of environment, ecology, and pollution control. In this research, extraction of dyes from madder at different conditions has been studied. The extracted dyes from madder were examined by TLC and HPLC. The adsorption properties of the dyes extracted from madder on natural polyamide fibers (wool) were also determined. The rate of dyeing at different temperatures, as well as the values of standard affinity, entropy, and enthalpy was calculated. The results indicated that increase of temperature leads to decrease the values of partition ratio and affinity. The adsorption isotherm was tested by fitting the adsorption data with Langmuir, Freundlich, BET, and Temkin isotherms. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

TiO2/PVDF共混微滤膜的制备及其吸附胆红素的研究

胆红素是一种内源性毒素,当人体肝脏系统受损或代谢受阻时,则在体内累积,引起高胆红素血症,其具有神经毒性,严重时甚至会危及生命。无机纳米材料作为胆红素吸附剂越来越受到关注,但也存在因团聚而吸附效率降低、因颗粒过小而容易泄漏的问题。以聚偏氟乙烯(PVDF)为基膜原料,掺杂纳米TiO₂颗粒,DMAc为溶剂、PVP为致孔剂,通过干湿相转化法,制得TiO₂/PVDF共混微滤膜。当铸膜液中PVDF浓度为10%(质量)、TiO₂含量为1%(质量)、PVP含量为6%(质量)时,制备的TiO₂/PVDF共混微滤膜的胆红素特异性吸附显著。电镜照片及EDX能谱发现,该膜内部及孔隙中均匀分布TiO₂颗粒,颗粒无团聚现象。实验还考察了胆红素初始浓度、吸附时间、吸附温度、pH等吸附条件的影响。     

Preparation and characterization of CMCS/PVA blend membranes and its sorption and pervaporation performance (I)

Novel pervaporation (PV) membranes for ethanol dehydration were prepared by blend poly(vinyl alcohol) (PVA) and carboxymethyl chitosan (CMCS), followed by the crosslinking reaction with glutaraldehyde; the structure and miscibility of the blend membranes were characterized by Fourier transform infrared, X‐ray diffraction, and differential scanning calorimetry; the results indicated that the blends were miscible. The effect of feed concentration, operation temperature, crosslinking agent content, etc. on sorption performance and PV performance of the blend membrane is investigated. The membrane of CMCS/PVA blend ratio of 8 : 2 exhibited a high separation factor of 2959 with a reasonably high water flux value of 0.14 kg m^?2h^?1 at the azeotropic feed composition (95 wt % of ethanol) at a temperature of 45°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

ACF电吸附过程动力学特性和脱盐影响因素试验研究

近年来,国家强化了对各类污水的治理力度和排放标准。其中,工业废水具有较大的节水与回用潜能,急需一种高效低成本的脱盐技术。目前电吸附技术凭借其能耗低、无需添加药剂、除盐效率高等特点在水处理领域广泛应用。采用电吸附技术实现废水快速脱盐主要从脱盐速度提高和高通量产水2个方面入手。由于动力学因素决定了离子在吸附剂内部的吸附速率,吸附容量决定除盐率,因此探究影响电吸附过程动力学特性和脱盐影响因素是该技术的关键。以活性炭纤维为电极材料,在自制的板式电吸附装置进行多组电吸附试验,研究进样浓度、外加电压、进样液pH值和温度对其除盐效率和饱和吸附容量的影响,并对不同电压、不同浓度下的电吸附动力学结果进行拟合。动力学研究表明:电压是离子吸附速率的主要因素;电压<0.8 V时,适用于准二级动力学方程,电压>0.8 V后适用一级动力学模型,电压越大离子吸附速率越快。等温吸附模型研究表明:增大电压和初始浓度可以提高电吸附容量,吸附过程适用Langmuir吸附等温模型来描述。弱酸性条件更有利于电吸附除盐性能的提高;温度升高对离子吸附有抑制作用,室温为最佳试验温度。     

Moisture sorption in relation to some characteristics of coal

Adsorption of water on sub-bituminous lower bed maghara coal and its carbonization products has been studied at 30°C. Adsorption of carbon dioxide at 25°C was also carried out for the aim of comparison. Some characteristics of coal were also investigated, these were namely, the i.r. spectra of surface functional groups and the weight loss on evacuation in the temperature range 30–140°C. Adsorption of water is related to the surface functional groups rather than to the extent of the surface. Moisture sorption may be reversible and can be expelled only by reducing the relative pressure at the isotherm temperature or irreversible in which much severe conditions are necessary.     

Moisture Sorption Isotherms and Storage Stability of Spray-Dried Yogurt Powder

Moisture adsorption isotherms of spray-dried yogurt powder were determined at 10, 25, and 40°C using the standard, static-gravimetric method. Experimental data were fitted to five mathematical models (Guggenheim-Anderson-de Boer [GAB], Brunauer-Emmett-Teller [BET], Halsey, modified Oswin, and modified Henderson). A nonlinear regression analysis method was used to evaluate the constants of the sorption equations. The shelf-life of yogurt powder was predicted based on the relationship between permeability coefficient of the packaging material and moisture adsorbed by the powder determined by the GAB equation. Furthermore, the storage stability of spray-dried yogurt powder in terms of quality parameters including moisture content, water activity, color change, and thiobarbituric acid (TBA) value was studied in aluminum laminated polyethylene (ALPE) pouches under storage conditions of 25°C and 50% relative humidity (RH).     

反式-1,4-聚异戊二烯的结晶性对丁苯橡胶/反式-1,4-聚异戊二烯共混硫化胶动态力学性能的影响

用动态力学分析仪和差示扫描量热仪研究了丁苯橡胶(SBR)/反式-1,4-聚异戊二烯(TPI)共混硫化胶的动态力学性能和结晶性能。结果表明,SBR与TPI的两相相容性良好。随着TPI用量的增加,SBR/TPI共混硫化胶的玻璃化转变温度向低温方向移动,且损耗因子峰值逐渐降低。用炭黑填充CV体系硫化SBR/TPI共混胶的损耗因子峰值低于相应的未填充胶料;而当TPI晶体熔融后,炭黑填充胶料的损耗因子要大于未填充者。不同硫化体系硫化SBR/TPI共混胶的损耗因子峰值和玻璃化转变温度从大到小的变化依次为CV体系、EV体系和DCP体系。     

聚乙烯醇共混及共混纤维的研究进展

综述了聚乙烯醇与天然和合成高分子材料共轭研究方面的进展,同时介绍了有关聚乙烯醇共混纤维的研究现状,并对今后的研究开发提出了一些建议。