Anti-fouling ultrafiltration membrane prepared from polysulfone-graft-methyl acrylate copolymers by UV-induced grafting method

Membrane fouling is one of the most important challenges faced in membrane ultrafiltration operations. The copolymers of polysulfone-graft-methyl acrylate were synthesized by homogeneous photo-initiated graft copolymerization. The variables affecting the degree of grafting, such as the time of UV （Ultraviolet-visible） irradiation and the concentrations of the methyl acrylate and photoinitiator, were investigated. The graft copolymer membranes were prepared by the phase inversion method. The chemical and morphological changes were characterized by attenuated total reflection-Fourier transform infrared spectroscopy （ATR/FT-IR）, scanning electron microscopy, and water contact angles measurements. Results revealed that methyl acrylate groups were present on the membranes and the graft degree of methyl acrylate had remarkable effect on the performance of membranes. Pure water contact angle on the membrane surface decreases with the increase of methyl acrylate graft degree, which indicated that the hydrophilicity of graft copolymer membranes was improved. The permeation fluxes of pure water and bovine serum albumin solution were measured to evaluate the antifouling property of graft copolymer membranes, the results of which have shown an enhancement of antifouling property for graft copolymer membranes.

UV接枝聚硅氧烷-TiO_(2)复合棉织物的制备及性能

通过紫外辐射3-(异丁烯酰氧)丙基三甲氧基硅烷对棉织物进行接枝聚合改性,然后与钛酸四丁酯共水解,形成Si—O—Ti化学键,通过化学键合的形式引入TiO_(2)层。由于Si元素位于棉织物和二氧化钛之间,阻断TiO_(2)光催化降解棉织物。化学键合TiO_(2)与棉织物的结合强度高,提高了耐久性。TiO_(2)对棉织物的整体结构未造成改变,但棉织物的抗紫外线能力显著提升,禁带宽度变小,光催化自清洁能力增强。

EFFECTS OF ORGANIC COLORANTS ON PHOTO-INITIATED CROSSLINKING AND PHOTO-OXIDATION DEGRADATION OF POLYETHYLENE AND RELATED MECHANISM

The effects of three organic colorants on photo-initiated crosslinking and photo-oxidation degradation of polyethylene (PE) samples irradiated by microwave excited (MWE) UV lamp in the melt and the related mechanism have been studied by gel content and thermal extension rate determinations,X-ray photoelectron spectroscopy (XPS),mechanical property tests,UV spectroscopy,and light microscope.The data from the gel content and thermal extension rate determinations of photo-crosslinked polyethylene (XLPE) sample...

Photo-Grafting Copolymerization of PP Nonwoven Fabric and Its Application for Acidic Dye Adsorption and Filtration

The monomer methacrylamido propyl trimethy ammonium chloride( MAPTAC) was copolymerized onto the fiber surface of polypropylene( PP) nonwoven fabric under ultroviole radiation. The weak acid red GN dye adsorption and adsorptive filtration performance of the resulted PP fabrics were investigated.The results showed that the grafting copolymerization preferred to happen in the inner layer of the fabrics. The water flux of the grafted fabrics decreases with the increase of grafting yield. The collapse of the grafted polymer chains causes the flux increase in acidic condition,or vice versa at alkaline version. The coiling of the polyelectrolyte chains upon the dye adsorption seems to violate the routine assumption of the rigid substrate, and this gets the adsorption energy constant negative. The static adsorption process follows the Lagergren's pseudo-second order kinetic equation. The removals of circa( ca.) 100% of the total permeation volume3 500 mL simulated dye wastewater was reached during permeation.The dye adsorbed fabrics were regenerated by the mixed media of the cationic surfactant / ethanol /water. The grafted fabric assumes stable fabric integrity and stability during permeation,and presents excellent dye adsorption capacity,easy desorption, and repeatable utilization.

UV-induced Self-initiated Graft Polymerization of Acrylamide onto Poly(ether ether ketone)

Photo-grafting of hydrophilic monomer was used to enhance the hydrophilicity of poly（ether ether ketone） （PEEK） with the aim of extending its applications to biological fields. PEEK sheets were surface modified by grafting of acrylamide（AAm） with ultraviolet（UV） irradiation in the presence or absence of benzophenone（BP）. The effects of BP, irradiation time and monomer concentration on the surface wettability of PEEK were investigated. Characteriza tion of modified PEEK using scanning electron microscopy（SEM）, energy-disperse spectrometer（EDS） and water contact angle measurements shows that AAm was successfully grafted on PEEK surface both in presence and absence of BP. With the increase in irradiation time and monomer concentration, contact angles decrease to as low as 30°, demonstrating a significant improvement of surface hydrophilicity. In agreement with the decrease in contact angle, under identical conditions, the nitrogen concentration increases, suggesting the increase in grafting degree of the grafting polymerization. This investigation demonstrates a self-initiation of PEEK due to its BP-like structure in the backbone of the polymer. Though the graft polymerization proceeds more readily in the presence of BP, the self-initiated graft polymerization is clearly observed.

THE EFFECTS OF MAGNETIC FIELD ON GRAFT COPOLYMERIZATION OF METHYL METHACRYLATE ONTO POLYVINYL ALCOHOL IN THE PRESENCE OF BENZOPHENONE DURING UV IRRADIATION

The effects of magnetic field on the graft ratio and stereoregularity of grafts of PVA-g-MMA in the presence ofbenzophenone during UV irradiation are discussed. By means of IR, it was found that the graft ratio was increased with the increment of magnetic field strength. Furthermore, application of relative weak magnetic field of 0.4 Tesla had been shown to substantially enhance the stereo-regularity of graft copolymer. The maximum stereo-regularity appeared when the graft ratio approached to 85% with the magnetic field of 1.2 Tesla (T). The resistance to moisture and heat resistance of the grafted copolymer in the presence of magnetic field were also improved.

PHOTOINDUCED GRAFTING OF ACRYLIC AND ALLYL MONOMERS ON POLYETHYLENE SURFACE

Photoinduced grafting of acrylic and allyl monomers on polyethylene surface was generally studied by using benzophenone (BP) as a photoinitiator. The grafting process was carried out either in vapor-phase or in solution of the monomers. In the vapor-phase reaction with a filter used to cut off the short wavelength UV light, allyl amine is the most reactive of the four monomers used and acrylic amide is comparatively more reactive than acrylic acid and allyl alcohol. Acetone, as a solvent and carrier for initiator and monomers, however, shows its reactivity to participate the reaction. The solution grafting with a filter is much faster than the corresponding vapor-phase reaction, and a fully covered surface by the grafted polymer can be achieved in this way.

Surface Graft Polymerization of PET and PE Fibers by UV Irradiation and Their Characteristics

Polyethylene terephthalate(PET)and polyethylene(PE)fibers were surface photo-grafted with acrylic acid(AA)by using UV irradiation photochemical initiationduring a continuous winding process within 1-2 min-utes.The grafted fibers were characterized by measure-ments of dye uptaking,moisture regain,pull-out forcesof monofilament from cured matrix,as well as by analy-sis of ESCA and ATR-FTIR spectra.All these resultsconfirm that the surface behavior of the UV-irradiationgrafted fibers was greatly improved.It was also provedthat the original excellent mechanical properties of the fi-bers were well-retained after the surface grafting treat-ment.

UV改性DACRON材料抗细菌粘附研究

介绍了对人工心瓣植入用涤纶布 (Dacron)表面以紫外辐照为主进行接枝改性的方法 ,在其材料表面引入聚乙二醇 (Polyethlene glycol,PEG) ,利用 PEG的“化学放大”作用再引入肝素 (Heparin,Hep) ,改性后的材料抗细菌粘附效果显著 ,与未改性材料相比 ,细菌粘附减少 90 %。

淀粉-丙烯酰胺接枝共聚物的UV合成及絮凝效果

采用UV(紫外光)聚合法合成了淀粉丙烯酰胺接枝共聚物(St-PAM)。通过实验研究了UV法合成St-PAM的影响因素和最佳工艺条件;对合成物进行了检测和絮凝效果试验。结果表明,UV法合成淀粉丙烯酰胺接枝共聚物是可行的,其合成物用作絮凝剂时,具有相当于或优于PAM的絮凝效果。

UV聚合法制备淀粉和丙烯酰胺接枝共聚物及其性能表征

以淀粉与丙烯酰胺 (AM)为原料 ,采用UV聚合法制备淀粉与丙烯酰胺接枝共聚物 (St-PAM)。通过实验得出较佳的工艺条件为 :淀粉糊化温度为 90℃ ;糊化时间为 1h ;AM与淀粉的最佳配比为 1:1 6 (质量比 ) ;引发剂用量是 1 2g/L ,交联剂用量 3g/L ,在此条件下得到的接枝共聚物接枝率和接枝效率最高。用IR对产物的结构进行了表征 。

UV辐照尼龙-6渔网材料的凝胶化改性研究

本研究采用紫外线(UV)对渔网材料尼龙-6纤维辐照,继而进行接枝AA的表面凝胶化改性研究,以制备一种能防止海洋污损生物附着的渔网材料。研究了辐照条件、凝胶化改性接枝条件等对接枝反应的影响以及凝胶化改性纤维的性能。研究结果表明,采用UV预辐照,可以显著提高尼龙-6纤维对AA的接枝率。接枝率随单体浓度、接枝反应时间的增加而升高;随接枝反应温度的增加先升高后又有所下降;一定量的无机酸使接枝率明显提高;随着阻聚剂盐用量的增加接枝率先增加而后又降低。扫描电镜观察接枝纤维表面可以证实接枝物的存在。接枝AA后尼龙-6纤维的吸水率明显升高,力学性能有所降低。

水性UV树脂聚合用可光引发纳米SiO_2的制备

采用氯化亚砜使纳米SiO2表面的羟基被氯原子取代后与水性光引发剂2959发生反应,制备出可引发水性UV树脂聚合的功能纳米SiO2,研究了反应温度和反应时间对纳米SiO2表面接枝率的影响,并用红外光谱仪(FT-IR)、粒径测试仪和热重分析仪(TG)对其进行分析和表征。FT-IR和粒径测试结果表明,水性光引发剂2959成功地被接枝到纳米SiO2表面。TG分析表明,反应温度为40℃和反应时间为4 h时,纳米SiO2表面聚合物接枝率较好,分别为15.94%和17.37%。红外分析结果表明,改性SiO2经过改性后由于其表面接枝了光引发剂2959而具有一定的光引发聚合功能。

基于自组装和UV-辐射的GO/PES/SPSf复合膜的制备及其染料/盐选择性分离性能

为实现染料和盐选择性分离,以PES/SPSf共混超滤膜为支撑体,采用层层自组装构建氧化石墨烯(GO)负载PES/SPSf复合膜,并且借助UV-光辐射(15 min)实现GO功能层与支撑层进一步交联及固定化,最后成功制备出GO/PES/SPSf复合膜;重点考察GO负载量对膜表面形貌、断面结构、亲水性、荷电性和渗透分离性能的影响。结果表明:当GO负载量为202 mg/m^(2)时,制备的复合膜纯水渗透率为53 L/(m^(2)·h·bar)(1 bar=0.1 MPa),对靛蓝磺酸钠(ICO)截留率为87.9%;在不同pH值和高含盐染料废水处理过程中,该复合膜对刚果红(CR)的截留率在90%以上,通量恢复率高达83%,表现出优异分离性能和运行稳定性。

光引发剂接枝星型SBS的合成及其UV改性压敏胶的研究

探索了一种光引发剂接枝型的苯乙烯类热塑性弹性压敏胶的制备方法。具体实验步骤是:以马来酸酐(MAH)和四氨基二苯甲酮(4-ABP)为单体合成4-马来酰亚胺基二苯甲酮(MBP);然后在过氧化二苯甲酰(BPO)的催化作用下,合成MBP接枝星型SBS的聚合物,采用NMR、FTIR分别对MBP和SBS-g-MBP的结构进行了表征,并通过测量紫外光固化后交联体系的凝胶含量对交联程度进行分析;再用SBS-g-MBP、增粘树脂、软化剂和防老剂配制成溶剂型UV固化胶粘剂,在牛皮纸上进行了粘结性能测试,压敏胶粘性能符合国家标准的牛皮纸压敏胶粘带的技术要求(HG/T2480-92。

PHOTO-INDUCED GRAFT POLYMERIZATION OF ACRYLAMIDE ON POLYPROPYLENE MEMBRANE SURFACE IN THE PRESENCE OF DIBENZYL TRITHIOCARBONATE

Ultraviolet （UV）-induced graft polymerization of acrylamide （AAm） on polypropylene substrates was successfully conducted using dibenzyl trithiocarbonate （DBTTC） as photoinitiator. It was confirmed by chemical analysis and surface morphology observation with attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. A possible mechanism for this graft process was presented, which suggested that, under UV irradiation, the C： S bond in DBTTC could split and abstract a hydrogen from the polypropylene surface and a surface free radical was then formed, and initiated the graft polymerization of AAm.

UV固化液体聚异戊二烯橡胶改性物的合成

用液体聚异戊二烯橡胶和马来酸酐的接枝物与丙烯酸-β-羟乙酯在碱性条件下酯化制备了改性物,并探讨了反应温度、接枝物浓度、反应物配比、催化剂用量、反应时间对酯化反应改性的影响.实验结果表明:当反应温度为90℃、接枝物浓度为35%、接枝物与丙烯酸-β-羟乙酯的摩尔比为1∶40、催化剂质量分数为2%、反应时间为3 h时,可得到单酯化率为81.52%的酯化物,并对该液体聚异戊二烯橡胶改性物在紫外光辐照下的固化性能进行了表征.

Ultravilolet-radiation-induced graft polymerization of acrylamide onto the melt-blown polypropylene filter element by dynamic method

By dynamic method under UV irradiation, commercial melt-blown polypropylene （PPMB） filter element was modified with acrylamide （AAm） using benzophenone （BP） as initiator. Attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscope verified that polyacrylamide chain was grafted on the fiber surface of PPMB filter element. Elemental content analysis with energy dispersive X-ray of fibers revealed that the polymerization content in the inner part of filter element was relatively higher than that in the outer. Degree of grafting changed with initiator concentration, monomer concentration, reaction temperature and reached 2.6% at the reaction condition： CBp=0.06 mol/L, CAAm=2.0 mol/L, irradiation time： 80 min, temperature： 60℃. Relative water flux altered with the hydrophilicity and pore size of filter element. In the antifouling test, the modified filter gave greater flux recovery （approximately 70%） after filtration of the water extract of Liuweidihuang, suggesting that the fouling layer was more easily reversible due to the hydrophilic nature of the modified filter.

聚醚胺接枝丙烯酸用于UV喷墨分散剂的研究

为了提高UV喷墨油墨的分散稳定性,利用高酸值固体丙烯酸树脂Joncryl 678和聚醚胺Jeffamine M2070进行接枝反应,制备了一种可用于UV喷墨油墨的超支化分散剂。实验结果表明,在一定范围内,随着聚醚胺比例的增大,聚合物的接枝程度增高,聚合物中游离羧基的数目减少,分散剂的酸值逐渐降低。由该超支化分散剂分别用于UV体系中钛白、酞青蓝、P.R. 122红、P.R.254红研磨,所得色浆分散性良好且具有良好的热稳定性,可以用于UV喷墨。

UV辐射和丙烯酸改性纤维改善纸张挺度

主要介绍在U V-反应基的接枝作用下研究有无丙烯酸酯处理对纸张强度和挺度的影响。1.2.3-UV-反应基上不同位置的官能团分别与不饱和酯反应生成三种不同官能单体。当三种官能单体加入纸张的浓度范围在5～20wt%（相对电荷电量：0.03～0.11mol.e q/AGU）之间时对纸张强度影响最大。本实验主要用纸张的强度和挺度指标来表征相关特性,研究发现在UV辐射后纸张的伸长率、抗张指数和杨氏模量都会增加;进一步研究发现有无丙烯酸酯化处理对纸张挺度没有太大的影响。实际上,丙烯酸酯化可以增强接枝反应,但却没有办法补偿酯化反应对纸张强度造成的影响。