聚丙烯酸接枝型聚偏氟乙烯多孔膜的pH值感应开关特性

A series of pH-responsive gating membranes, with a wide range of grafting yields, were prepared by grafting poly (acrylic acid) (PAAC) onto porous polyvinylidene fluoride (PVDF) membrane substrates with a plasma-induced pore-filling polymerization method. The effect of grafting yields on gating characteristics of pH-responsive gating membranes was investigated systematically. The results showed that the grafting yield heavily affected water flux, pH-responsiveness coefficient and pH-responsive gating factor of membrane pore size. When the grafting yield was smaller than 1.01%, both flux responsiveness coefficient and pH-responsive gating factor of pore size increased with increasing grafting yield. When the grafting yield was in the range from 1.01% to 6.44%, both flux responsiveness coefficient and pH-responsive gating factor of pore size decreased with increasing grafting yield; however, when the grafting yield was higher than 6.44%, both flux responsiveness coefficient and pH-responsive gating factor of membrane pore size approached to 1, i.e. , little gating characteristics existed. In order to obtain a satisfactory pH-responsive gating property of the membrane, the grafting yield must be kept in a proper range.     

温度感应式开关膜的接枝率对其开关特性的影响

利用等离子体诱导填孔接枝聚合法将聚(N-异丙基丙烯酰胺)（PNIPAM）接枝聚合在聚偏氟乙烯（PVDF）微孔膜上制备了一系列具有较宽接枝率范围的温度感应式开关膜,系统地研究了接枝率对膜的温度感应开关特性的影响.结果表明,开关膜的接枝率对膜的过滤通量、温度感应开关系数和膜孔径感温变化倍数都有十分重要的影响.接枝率在小于等于2.81%时,温度感应开关系数和膜孔径感温变化倍数均随接枝率增加而增加;而对于接枝率大于等于6.38%的膜,膜开关系数和膜孔径感温变化倍数总是趋近于1,膜不具备温度感应开关特性.为了获得预期的开关性能,必须将膜的接枝率控制在适当的范围.     

温度感应复合型控制释放膜系统的性能研究

采用等离子诱导填孔接枝聚合法将聚N-异丙基丙烯酰胺(PNIPAM)开关接枝到聚偏氟乙烯膜(PVDF)膜孔上,同自由基聚合法制备的PNIPAM交联水凝胶结合,成功地组成了一种温度感应复合型控制释放膜系统。在该膜系统中,PNIPAM接枝PVDF膜作为控制释放开关,PNIPAM交联水凝胶作为药物载体。通过改变交联水凝胶和开关膜的微观结构,研究了该复合膜系统的温度感应控制释放特性。结果表明,该复合膜系统具有良好的温度感应特性,优于单独的开关膜控制释放系统或是单独的交联水凝胶控制释放系统。研究结果将为温度感应型控制释放系统或给药系统的设计与开发提供理论基础。     

温度、pH双重敏感聚氨酯膜的制备及其智能特性

以温敏聚氨酯(TSPU)材料为基膜,利用表面接枝改性技术将带有对pH敏感的官能团(丙烯酸)引发接枝到基膜的表面,成功制备了一种对温度、pH双重敏感的聚氨酯膜.红外光谱分析发现,在接枝膜的谱图上出现了羧基的特征吸收峰,说明丙烯酸已成功接枝到TSPU膜上.扫描电镜对接枝膜形貌观察表明,在TSPU膜的表面,具有明显的聚丙烯酸...     

接枝量对等离子体接枝聚异丙基丙烯酰胺开关的多孔膜的温度感应透过性的影响

The effect of graft yield on both the thermo-responsive hydraulic permeability and the thermo-respousive diffusional permeability through porous membranes with plasma-grafted poly(N-isopropylacrylamide) (PNIPAM)gates was investigated. Both thermo-respousive flat membranes and core-shell microcapsule membranes with a wide range of graft yield of PNIPAM were prepared using a plasma-graft pore-filling polymerization method. The grafted PNIPAM was formed homogeneously throughout the entire thickness of both the fiat polyethylene membranes andthe microcapsule polyamide membranes. Both the hydraulic permeability and the diffusional permeability were heavily dependent on the PNIPAM graft yield. With increasing the graft yield, the hydraulic permeability (water flux) decreases rapidly at 25℃ because of the decrease of the pore size; however, the water flux at 40℃ increases firstly to a peak because of the increase of hydrophobicity of the pore surface, and then decreases and finally tends to zero because of the pore size becoming smaller and smaller. For the diffusional permeability, the temperature shows different effects on the diffusional permeability coefficients of solutes across the membranes. When the graft yield was low, the diffusional coefficient of solute across the membrane was higher at temperature above the lower critical solution temperature (LCST) than that below the LCST; however, when the graft yield was high, the diffusional coefficient was lower at temperature above the LCST than that below the LCST. It is very important to choose or design a proper graft yield of PNIPAM for obtaining a desired thermo-respousive “on/off“ hydraulic or ditfusional permeability.     

磁性温度感应微囊膜的制备与表征

合成了亲油Fe3O4纳米颗粒,然后采用界面聚合法制备了磁性聚酰胺多孔微囊膜,最后用等离子体填孔接枝聚合法将聚N-异丙基丙烯酰胺(PNIPAM)接枝到微囊的多孔膜上,制得了磁性温度感应微囊膜.利用X射线衍射(XRD),傅里叶变换红外光谱(FT-IR),透射电镜(TEM)对Fe3O4颗粒进行了表征;用扫描电镜(SEM)、振动样品磁强计(VSM)、磁场分离实验和对VB12的温度感应控释实验对微囊进行了表征.结果表明,未接枝的微囊膜为非对称多孔结构,接枝微囊膜具有超顺磁性,在水溶液中的磁场响应性能良好,对模拟药物有一定的温度感应控制释放特性.     

智能膜开关尺寸与孔径的匹配性对膜响应性能的影响规律

智能膜的响应性能是其主要性能之一。本文借助计算流体力学（CFD）模拟,以孔壁排布有聚N-异丙基丙烯酰胺（PNIPAM）智能微球的单直膜孔为模型,定量系统地考察了智能微球的响应倍数以及微球尺寸与膜孔径的匹配性对膜温度响应性能的影响规律,并通过实验验证了模拟结果的可靠性。CFD模拟结果表明,当智能开关与膜孔径的相对比值一定时,温度响应开关系数随着微球响应倍数的减小而逐渐增大。当相对比值小于0.4时,实测的温度响应开关系数与固载量100%的模拟结果相吻合;而当相对比值大于0.4时,其与固载量为67%的模拟结果相吻合。通常当相对比值在0.4～0.65之间时,智能膜可以同时获得良好的温度响应性能和稳定的渗透性能。该研究结果可望为设计和制备高性能智能膜提供理论指导和实验基础。     

离子膜电解装置的pH值控制问题探讨

根据离子膜电解装置加酸各个环节影响因素,探讨加酸的工艺技术控制现象,寻求控制理想加酸的各环节,保证加酸品质.     

浮选矿浆pH值和温度的在线检测系统

分析了浮选生产工艺中对矿浆pH值和温度参数检测的特点，在此基础上，采用AST386为上位机，MCS－51系列单片机为下位机构造了一种集散型分布式检测系统。下位机控制仪表完成现场数据的实时采集和处理任务，上位机集中巡回监测各检测点的参数变化并进行各种管理操作。运行情况表明，该系统性能可靠、使用方便，并可推广应用于其它工业领域。     

Effect of Graft Yield on the Thermo-Responsive Permeability Through Porous Membranes with Plasma-Grafted Poly(N-isopropylacrylamide)Gates

The effect of graft yield on both the thermo-responsive hydraulic permeability and the thermo-responsive diffusional permeability through porous membranes with plasma-grafted poly(AT-isopropylacrylamide) (PNIPAM) gates was investigated. Both thermo-responsive flat membranes and core-shell microcapsule membranes with a wide range of graft yield of PNIPAM were prepared using a plasma-graft pore-filling polymerization method. The grafted PNIPAM was formed homogeneously throughout the entire thickness of both the flat polyethylene membranes and the microcapsule polyamide membranes. Both the hydraulic permeability and the diffusional permeability were heavily dependent on the PNIPAM graft yield. With increasing the graft yield, the hydraulic permeability (water flux) decreases rapidly at 25℃ because of the decrease of the pore size; however, the water flux at 40℃ increases firstly to a peak because of the increase of hydrophobicity of the pore surface, and then decreases and finally tends to zero because o     

高分子多孔膜的表面改性与抗污染研究

采用羟基化预处理、铈盐引发和碱化预处理、Fe2 /H2O2引发两种引发体系,对聚砜(PS)膜和聚丙烯腈(PAN)膜进行表面接枝丙烯酰胺的改性,研究预处理和表面接枝改性对膜污染的影响。采用红外光谱和X光电子能谱对羟基化和接枝改性的膜表面进行表征。研究表明,表面预处理和接枝后,PS膜和PAN膜的水通量均有所下降,但提高了抗牛血清蛋白膜污染能力。     

聚合物分离膜接枝改性技术及应用

介绍了化学、等离子体、辐射和光化学等应用于聚合物分离膜领域的接枝技术的主要特点。对接枝技术在聚合物分离膜的制备、改性、功能化和高性能化等领域的应用进行了总结。     

多孔膜基材对等离子体接枝膜微观结构的影响

采用等离子体诱导接枝聚合法,在有机聚偏氟乙烯(PVDF)膜、尼龙(N6)膜和无机多孔阳极氧化铝(PAA)膜上接枝甲基丙烯酸(MAA),系统地研究了多孔膜基材及接枝工艺条件对接枝开关膜微观结构的影响。结果发现,对于PVDF基材膜,单体溶液脱气次数越多接枝率越大。对于不同类别的多孔膜基材,采用相同工艺条件接枝时,N6膜的接枝率高于PVDF膜,PAA膜接枝率最低。在接枝率相近的时候,接枝层在PVDF膜整个断面孔内和表面均存在,而N6膜则主要集中在表层。在PAA膜上接枝时发现,等离子体照射功率的强弱对基材膜的影响很大,当功率超过50W时,PAA膜表层就会被刻蚀而导致膜的质量减轻。     

Thermo-Responsive Ultrafiltration Block Copolymer Membranes Based on Polystyrene-block-poly(diethyl acrylamide)

Within the present work, a thermo-responsive ultrafiltration membrane is manufactured based on a polystyrene-block-poly(diethyl acrylamide) block copolymer (BCP). The poly(diethyl acrylamide) block segment features a lower critical solution temperature (LCST) in water, similar to the well-known poly(N-isopropylacrylamide), but having increased biocompatibility and without exhibiting a hysteresis of the thermally induced switching behavior. The BCP is synthesized via sequential “living” anionic polymerization protocols and analyzed by ¹H-NMR spectroscopy, size exclusion chromatography, and differential scanning calorimetry. The resulting morphology in the bulk state is investigated by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) revealing the intended hexagonal cylindrical morphology. The BCPs form micelles in a binary mixture of tetrahydrofuran and dimethylformamide, where BCP composition and solvent affinities are discussed in light of the expected structure of these micelles and the resulting BCP membrane formation. The membranes are manufactured using the non-solvent induced phase separation (NIPS) process and are characterized via scanning electron microscopy (SEM) and water permeation measurements. The latter are carried out at room temperature and at 50 °C revealing up to a 23-fold increase of the permeance, when crossing the LCST of the poly(diethyl acrylamide) block segment in water.     

膜色谱所用微孔膜接枝改性的初步研究

结合膜色谱分离蛋白质的应用背景,采用钴源辐射接枝法和紫外辐射接枝法对聚乙烯膜进行了膜孔表面接枝改性的初步研究与探讨。