聚砜超滤膜表面辐照改性研究

以聚砜为膜材料,聚乙二醇（PEG）为添加剂,采用浸入沉淀相转化法制备聚砜平板超滤膜,然后对实验制备的聚砜膜进行紫外辐照改性,考察了辐照对聚砜膜结构和性能的影响,研究了膜辐照前后断裂强度的变化,通过表面接触角测定仪、红外分析仪（FTIR）、扫描电镜（SEM）、改性膜的纯水通量和截留性能等方法来表征膜辐照前后的结构和性能变化。研究表明,聚砜膜断裂强度经辐照后强度变小,但是降低幅度不大;在乙醇溶液中紫外辐照后,开始纯水通量提高而截留率降低,但降低幅度不大,时间增加到一定时通量又降低,截留率变化也不大;表面接触角随辐照时间的增长而减小,表明改性后膜表面的亲水性得到明显改善;通过FTIR分析证实在聚砜膜表面产生了新的官能团;SEM实验证实反应只发生在聚砜膜的表面而非膜内部。聚砜超滤膜经紫外辐照改性取得了良好的效果。     

聚砜超滤膜表面辐照改性研究

以聚砜为膜材料,聚乙二醇(PEG)为添加剂,采用浸入沉淀相转化法制备聚砜平板超滤膜,然后对实验制备的聚砜膜进行紫外辐照改性,考察了辐照对聚砜膜结构和性能的影响,研究了膜辐照前后断裂强度的变化,通过表面接触角测定仪、红外分析仪(FTIR)、扫描电镜(SEM)、改性膜的纯水通量和截留性能等方法来表征膜辐照前后的结构和性能变化.研究表明:聚砜膜断裂强度经辐照后变小,但降低幅度不大;在乙醇溶液中紫外辐照后,开始纯水通量提高而截留率降低,但降低幅度不大,时间增加到一定时通量又降低,截留率变化也不大;表面接触角随辐照时间的增长而减小,表明改性后膜表面的亲水性得到明显改善;通过FTIR分析证实在聚砜膜表面产生了新的官能团;SEM实验证实反应只发生在聚砜膜的表面而非膜内部.聚砜超滤膜经紫外辐照改性取得了良好的效果.     

~(60)Co γ-射线辐照接枝对聚乙烯隔膜结构及性能的影响

以聚乙烯(PE)膜为基材,选择亲水性较好的甲基丙烯酸甲酯(MMA)作为接枝单体,在PE膜上进行~(60)Co γ-射线辐照接枝改性,研究了辐照剂量和接枝溶液MMA浓度对改性PE膜性能的影响,并对改性PE膜的结构和形貌进行表征。结果表明:经过适当的辐照接枝改性处理后,MMA单体被成功接枝到PE膜表面;随辐照剂量和接枝溶液MMA浓度的提高,改性PE膜的亲水性能得到较大提高,力学性能变差,相同热处理条件下的热收缩率均明显降低;当接枝溶液中MMA体积分数为15%,辐照剂量为100 k Gy时,改性PE膜的接触角降低至86.93°,拉伸强度降至19.99 MPa,断裂伸长率降至0.27%,且在150℃,30 min热处理条件下,改性PE膜的热收缩率下降到14.5%。     

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。     

聚砜类膜和膜材的改性

聚砜膜广泛应用于生物学分离上，但由于其蛋白质污染问题，导致膜的通透率下降，选择性改变。目前解决这一问题的办法是对膜或膜材进行亲水性改性。就聚砜类膜和膜材的改性情况作一概述，对比各种方法的优缺点，对聚砜类膜和膜材改性前景进行了展望。     

聚砜超滤膜表面辐照改性研究

实验以聚砜为膜材料,聚乙二醇（PEG）为添加剂,采用浸入沉淀相转化法制备聚砜平板超滤膜,然后对实验制备的聚砜膜进行紫外辐照改性,考察了辐照对聚砜膜结构和性能的影响,研究了膜辐照前后断裂强度的变化,通过表面接触角测定仪、红外分析仪（FTIR）、扫描电镜（SEM）、改性膜的水通量和截留性能等方法来表征膜辐照前后的结构和性能变化,聚砜超滤膜经紫外辐照改性取得了良好的效果。     

利用低温等离子体进行聚砜膜的表面改性

利用低温等离子体引发接枝反应,在表面带负电的聚砜膜上引入带正电的单体聚合物,从而减少膜表面净电荷.通过测定膜的电渗流量来确定其表面电荷以作为膜表面改性效果的定量评价标准.考察了照射时间、照射功率和接枝反应时间对膜改性效果的影响,并对比了原膜与改性膜的膜污染特性.结果表明,改性后的膜表面净电荷减少,抗污染特性提高.     

表面紫外接枝辣素衍生物制备抗菌性聚砜超滤膜

以二苯甲酮(BP)为紫外接枝引发剂,将辣素衍生物N-(2,3,4-三甲氧基苯甲基)丙烯酰胺(TMBA)和丙烯酸(AA)接枝在聚砜基膜表面上以提高膜的抗菌性和耐污染性。在先前研究的基础上,试验固定接枝时间为15 min,TMBA和AA的质量分数分别为1%和2%,溶剂为乙醇,通过表面接触角测定仪、全反射红外光谱、扫描电镜、水通量和截留率、耐污染性、抗菌性测试等方法来表征膜改性前后的结构和性能变化,研究引发剂BP含量对膜表面结构性能的影响。结果表明,改性后聚砜超滤膜的截留率、耐污染性等都得到很好的改善,尤其是改性膜的抗菌性得到了明显提高;当BP的质量分数为0.2%时,抑菌率达到95%左右,通量恢复率由基膜的25%提高到80%,可以证明改性后的聚砜膜具有了良好的抗菌性和耐污染性。     

磺基甜菜碱接枝共聚物共混改性聚砜超滤膜的研究

两性离子具有超强的亲水性和抗污染能力,通常用于易污染疏水材料表面的接枝改性,提高其亲水性和抗污染性,但该接枝改性反应一般发生在固液反应体系中,导致反应效率低和难以工业化放大等缺陷。今以聚砜(PSU)接枝磺基甜菜碱甲基丙烯酸酯(SBMA)为研究对象,以二甲亚砜(DMSO)为溶剂,使该接枝反应在均相体系下发生。该反应以PSU上预先接枝的氯甲基为原子转移自由基聚合反应(ATRP)引发基团,在氯化亚铜(Cu Cl)的催化下合成PSU-g-SBMA共聚物。元素分析和红外检测的结果表明,随着SBMA添加量的提高,共聚物接枝率呈上升趋势,且在SBMA:PSU摩尔比为5:1时,接枝率达到最高值61.9%。随后,将制得的PSU-g-SBMA与PSU共混,经由相转化法制备超滤膜,通过表征发现该膜呈典型的指状大孔结构,且牛血清白蛋白(BSA)截留率大于90%,纤维蛋白截留率大于99%。共混膜的接触角和静态蛋白吸附量均比纯聚砜膜有极大下降,且通量恢复率有很大提升,表明PSU-g-SBMA共混改性可有效提高PSU膜的亲水性和抗污染能力。综上,本研究阐述了一种两性离子接枝共聚物共混改性超滤膜的新方法,克服了两性离子固液接枝反应体系的缺陷,有助于将来实现两性离子改性超滤膜的工业化生产。     

表面化学改性法制备抑菌性聚醚砜超滤膜

以辣素衍生物N-(5-甲基-3-异丁基-2羟基-苄基)-丙烯酰胺(HMBA)为改性材料,利用表面化学接枝法在聚醚砜(PES)超滤膜表面接枝辣素单体,提高膜的抑菌性。分别研究了单体含量、不同引发剂以及反应时间对接枝反应的影响;并采用全反射红外光谱(ATR-FTIR)对接枝前后聚砜膜进行表征,用原子力显微镜(AFM)观察接枝前后聚砜膜的形貌变化。结果表明,在单体的质量分数为1%,引发剂为过硫酸钾(K2S2O8)、焦亚硫酸钾(K2S2O5),处理时间60 min,接枝反应温度为40℃时,获得最佳接枝效果。接枝改性后的聚砜膜抑菌率达到80%,高于改性前的18%;表面水静态接触角能够降低到60°左右。     

Fouling control in a submerged membrane‐bioreactor by the membrane surface modification

To improve the antifouling characteristics, polypropylene microporous membranes (PPHFMMs) were surface‐modified by the sequential photoinduced graft polymerization of acrylic acid and acrylamide. The grafting density and the grafting chain length, which played important roles in the antifouling characteristics, were controlled in the first and the second step, respectively. The ATR/FTIR results clearly indicated the successful modification on the membrane surface. The static water contact angle of the modified membrane reduced obviously with the increase of the grafting chain length. The contact angle of the acrylic acid modified membranes was lower than that of the acrylamide modified membrane with similar grafting chain length. The grafting chain length increased with the increase of UV irradiation time and monomer concentration. The grafting chain length of poly(acrylic acid) (PAAc) was lower than that of the polyacrylamide (PAAm) under the same polymerization conditions. Pure water flux for the modified membranes increased with the increase of grafting chain length, and had maximums. The antifouling characteristics of the modified membranes in a submerged membrane‐bioreactor (SMBR) were evaluated. The modified membranes showed better filtration performances in the SMBR than the unmodified membrane, and the acrylic acid grafted membrane presented better antifouling characteristics than acrylamide modified membranes. The results demonstrated that the surface carboxyl‐containing membranes were better than the surface amido‐containing membranes. The results of Pearson correlations demonstrated that the PAAc modified membranes with longer grafting chain length had higher flux recoveries, while the PAAm modified membranes with longer grafting chain length had lower flux recoveries. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Improving the hydrophilicity of polyethersulfone membrane by the combination of grafting technology and reverse thermally induced phase separation method

In this work, surface grafting modification technology was combined with reverse thermally induced phase separation (RTIPS) method in order to improve the structure and permanent hydrophilicity of polyethersulfone (PES) membranes. Acrylic solution with different concentrations was grafted on the surface of PES membranes while grafting temperature and grafting time were also varied. The modified PES membranes were characterized in all aspects. Attenuated total reflectance Fourier transform-infrared confirmed successful modification of the PES membrane by grafting acrylic acid. Scanning electron microscopy revealed that homogeneous porous top surface as well as spongy-like cross-section structure appeared in the membrane by RTIPS procedure. Moreover, porosity was affected by changes of acrylic acid concentration, grafting temperature, and grafting time. Atomic force microscopy showed that grafting acrylic acid gave a reduction in roughness of PES membrane. Combined with the decreased values of contact angle, the hydrophilicity and antifouling performance of the PES membrane were improved. The pure water flux and BSA rejection rate of the grafted PES membranes were remarkably improved for pure PES membrane and attained a maximum, which was 1,646.24 L/(m²h) and 94.5%, respectively. The long-term test demonstrated that grafting membranes exhibited outstanding elevated water flux recovery ratio (>85%).     

紫外接枝丙烯酸对PVDF膜表面改性的研究

以二苯甲酮为光引发剂,通过紫外辐照将亲水性单体丙烯酸接枝于聚偏氟乙烯(PVDF)膜的表面。考察了光引发剂浓度和辐照时间对接枝率的影响,并利用衰减全反射光谱和扫描电子显微镜对接枝后PVDF膜表面的化学组成和微观形貌进行了表征。结果表明:随着光引发剂浓度的增大,丙烯酸的接枝率先增大后减小。通过纯水接触角和吸水率研究了接枝后的PVDF膜的亲水性,发现接枝后的PVDF膜的亲水性得到明显改善。     

Dialysis membranes from polyethylene films grafted with acrylic acid

Low‐density polyethylene‐g‐poly(acrylic acid) membranes were prepared by the direct radiation grafting of aqueous acrylic acid solutions (containing Mohr's salt) onto low‐density polyethylene films and were irradiated at two different irradiation doses (2 and 3 Mrad) at a dose rate of 0.02 Mrad/h. Two series of polyethylene‐g‐poly(acrylic acid) membranes with 100 and 150% grafting were obtained. The free carboxylic acid groups in the grafted films were converted into the corresponding acrylates by reactions with different metal salts. The swelling (water uptake) and dialysis permeability of glucose and urea through the grafted membranes in different metal‐ion forms were investigated. The prepared membranes showed good permeability to both solutes, which increased as the hydrophilicity of the membrane increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 10–14, 2004     

Novel fishnet fibers with anti‐adhesion of seaweeds obtained by UV‐irradiation technique

A novel Nylon‐6 fishnet fiber with the antiadhesion of seaweeds was prepared by UV radiation‐initiated grafting of acrylic acid (AA) onto Nylon‐6 fibers, and its structure was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The influences of grafting conditions, such as irradiation dose, temperature, concentration of monomer, inorganic acid, and inhibitor etc., on grafting rate were studied, and the antiadhesion of seaweeds was evaluated with Dunaliella. The results showed that the grafting amount of Nylon‐g‐AA was increased with the increase of irradiation time. With the increase of concentration of AA, temperature, reaction time, inorganic acid, and inhibitor, the grafting amount increased firstly and then decreased, respectively. Nylon‐6 fibers modified by Poly(acrylic acid) (PAA) had a strong effect on the adhesion of Dunaliella, and the antiadhesion was improved with the increase of the grafting amount. Results from the mechanical analysis revealed that the tensile strength of the UV‐irradiation fibers decreased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1252–1256, 2007     

The study on radiation grafting of acrylic acid onto fluorine-containing polymers. IV. Properties of membrane obtained by preirradiation grafting onto poly(tetrafluoroethylene–hexafluoropropylene)

Some properties of the membranes obtained by preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene–hexafluoropropylene) (FEP) film have been investigated. Swelling behavior, dimensional change by grafting, electric conductivity, and mechanical properties of the grafted films were found to depend largely on the degree of grafting and to increase as the grafting proceeds. These properties were also found to be independent of the preparation conditions such as irradiation dose, grafting temperature, film thickness, and monomer concentration lower than 60 wt %. The electric conductivity of the membranes prepared at lower monomer concentration (lower than 60 wt %) is higher than that prepared at 80 wt % acrylic acid concentration. X-ray microscopy of the grafted film revealed that the grafting proceeds from both surfaces of the film to the direction of center to give finally homogeneous grafting through the whole bulk of film. At lower monomer concentration the homogeneous grafting was achieved at a degree of grafting around 18%, while at 80 wt % acrylic acid it was achieved at a degree of grafting higher than 70%. The homogeneously grafted membranes show good electrochemical and mechanical properties which make them acceptable for practical uses as cation-exchange membranes.     

Modification of PES Membrane: Reduction of Biofouling and Improved Flux Recovery

A 0.22 µm polyethersulfone microfiltration membrane was modified using acrylic acid irradiated with UV light. The degree of grafting (DG) was confirmed by FTIR spectroscopy, which varied from 21 to 568 µg/cm² for differing irradiation times and initial monomer concentrations. The contact angle of the modified membranes was at least 10° less than the unmodified PES membrane. Modification filled the pores with copolymer, and decreased the permeability of the membrane. However, following the filtration of E. coli, and membrane cleaning, the flux recovery was 100% for the modified membranes and only 50% for the unmodified membranes. Thus, the modification helped in showing reversible biofouling and higher flux recovery.     

Modification of isotactic polypropylene by a cold plasma or an electron beam and grafting of the acrylic acid onto these activated polymers

Surface grafting of polymeric materials, such as films and fibers, may improve their reactive surface properties. Polypropylene active sites that should initiate a surface postgrafting can be formed by either nitrogen cold plasma or an electron-beam irradiation. The plasmamodified polymer surface is cross-linked and functionalized with primary amino groups and with oxidized groups, and it is almost not degraded. Electron-beam-modified polypropylene is also functionalized through an aging reaction, emphasized by a high radical concentration. In both cases, active surface films are susceptible to react with monomers in a postgrafting reaction. The grafting yield and rate of acrylic acid were shown to be dependent on the formed amino group concentration: The hydrophilic character of the modified polypropylene surface enhances the acrylic acid approach. The electron-beam treatment leads also to a reactive surface that can initiate a grafting reaction. But its yield and rate are dependent on the radical concentration: radicals formed during the irradiation. © 1994 John Wiley & Sons, Inc.     

Graft polymerization of acrylic acid onto polyethylene film by preirradiation method. II. Effects of oxygen at irradiation,storage time after irradiation,mohr's salt,and ethylene dichloride

In the grafting of acrylic acid onto polyethylene by preirradiation method, the irradiation in air gave a higher rate of grafting than in N₂, since the diffusion rate of monomer is larger for less crosslinked polyethylene. The rate of grafting decreased with increasing time of storaging polyethylene because of the decay of trapped radicals. The effects of storage conditions on the grafting activity was reasonably interpreted by assuming that grafting is predominantly controlled by both concentration of trapped radicals and monomer diffusibility in the polymer matrix. Mohr's salt was found to depress the homopolymerization of acrylic acid without marked change of grafting rate. The rate of grafting was increased by the addition of ethylene dichloride due to the increase in monomer diffusion.     

紫外光辐射接枝及胺化法制备温敏性聚乙烯薄膜

实验探索在水性体系中经紫外光辐射,引发丙烯酸(AAC)在聚乙烯(PE)薄膜表面接枝,并经过胺化反应,在已改性的丙烯酸-聚乙烯(AAC-g-PE)薄膜上继续引入功能团,使改性后的PE薄膜具有温度敏感性。考察了引发剂用量、紫外光照射时间对接枝率的影响,并对不同胺化剂合成产物的温敏效应进行比较,从而达到实验目的。通过红外光谱和尺寸变化率证明丙烯酸接枝在PE表面,胺化反应后,生成聚N-异丙基丙烯酰胺聚合聚乙烯(PNIAAm-g-PE)薄膜和聚N-正丙基丙烯酰胺聚乙烯(NNPA-g-PE)薄膜具有温敏性。