聚氨酯改性的微孔膜的制备与性质

PVC膜对糖类化合物有较强的排斥力,但其亲水性差,而聚氨酯有较强的亲水性,本课题研究聚氯乙烯(PVC)与聚氨酯(PU)的共混膜,探讨相转化法制备PVC/PU共混超滤膜的性能。实验结果表明,当聚合物浓度为16%,PVC/PU以8/2(质量分数)共混时,可制的水通量、截留率较好的多孔膜。     

碳纳米管对聚氨酯/聚氯乙烯共混膜性能的影响

以聚氨酯/聚氯乙烯(PU/PVC)共混物为基质,添加了多壁碳纳米管(MWCNT),采用湿法相转换法制备了PU/PVC共混膜。通过扫描电子显微镜(SEM)、透湿导热装置、接触角测量仪和拉伸试验对共混膜进行测试,研究了MWCNT对PU/PVC共混膜的断面形态、导热效率、亲水性及力学性能的影响。实验结果表明:添加MWCNT可以显著改善膜的孔结构,大孔数量明显减少,界面微孔数量显著增多,孔径变小,当MWCNT用量在一定范围内,导热效率、接触角、拉伸强度和断裂伸长率均有所提高。当MWCNT的用量为0.4%时,导热效率由25.18%提高到30.41%、接触角由68.50°增加到76.42°、拉伸强度由2.09 MPa增加到7.47 MPa、断裂伸长率由411%增加到469%,综合性能最优。     

PVC／PU合金的制备与研究

叙述了选择混炼型聚氨酯(PU)与分子量适中的Ⅱ型聚氯乙烯(PVC)树脂制备PVC/PU合金的过程,讨论了PVC/PU共混比、填充剂、硫化体系、共混工艺等因素对PVC/PU合金性能的影响。结果表明:选择PVC/PU=60/40(质量比),硫化剂TD15份,白炭黑30份,混炼温度140—160℃,可制得性能优良的PVC/PU合金。动态力学性能实验显示了PVC/PU合金有较好的相容性。     

PU对改善PSF/PU共混超滤膜性能的影响

为提高聚砜(PSF)超滤膜亲水性,增强其抗污染能力,以聚氨酯(PU)作为改性剂,采用沉淀相转化法制备PSF/PU共混超滤膜。用溶解度参数和共溶剂法等预测了PSF/PU是部分相容体系。同时,用接触角测定仪和拉伸强度仪对膜的亲水性、机械性能等进行了表征。结果表明,PU加入后,共混膜的接触角从90.17°下降到73.9°,亲水性提高;对明胶的吸附量从122.36μg/cm2下降为88.64μg/cm2,抗污染性提高;在m(PSF)/m(PU)=80/20时,膜的断裂伸长率由17.78%升高到36.78%,机械性能提高。     

聚氨酯/聚偏氟乙烯防水透气膜的制备及性能

采用湿法相转换法制备了聚氨酯/聚偏氟乙烯(PU/PVDF)共混膜。通过扫描电子显微镜(SEM)和X射线衍射(XRD)对PU/PVDF共混膜的形貌和结构进行表征,并对PU/PVDF共混膜进行了性能测试,研究了PVDF的含量对共混膜透气性、亲水性及力学性能的影响。结果表明:添加PVDF可显著改善膜孔结构,随着PVDF含量的增多,结晶度增大;共混膜的透气性、疏水性、拉伸强度及断裂伸长率均呈先上升后下降的趋势,并在PU/PVDF比例为80/20时,各值均达到最大值,此时,透气性由1.034 L/(cm2·min)增加到6.881 L/(cm2·min),接触角由71.67°增加到92.51°,拉伸强度由1.25 MPa增加到1.56 MPa,断裂伸长率由401%增加到460%,综合性能达到最大。     

PU/PVC共混超滤膜的制备及性能

采用湿法相转化制膜技术制备PU/PVC共混膜、PU/PVC/SiO2共混膜。PVC可以改变铸膜液体系在凝固浴中的分相速度,提高成膜性及改善膜的微孔结构,在此共混物中加入SiO2可以显著改善膜的微孔结构,并提高PU共混膜的水通量,可用于超滤。用扫描电镜对膜的结构形态进行了观察。     

PVC-SPES共混膜的制备及其在废水处理中的应用研究

为提高聚氯乙烯(PVC)膜的亲水性及其耐污染性,将聚醚砜(PES)磺化得到磺化聚醚砜(SPES),然后利用溶液共混的方法将PVC与SPES共混,通过溶剂-非溶剂扩散诱导相分离的方法制备了PVC-SPES共混膜。在此基础上对PVC-SPES共混膜的性能进行了测试,包括膜的断面和表面微观结构电镜扫描、水通量、截留率、机械强度、含水率和表面接触角的测试及膜表面化学成分的光电子能谱分析(XPS),同时对PVC膜与PVC-SPES共混膜在对生化降解后的污水过滤的情况进行了比较,结果表明,PVC-SPES共混膜为典型的非对称多孔膜;PVC-SPES共混膜水通量、机械强度和亲水性较PVC膜有显著提高,截留率略有下降;PVC-SPES共混膜比PVC膜具有更优良的耐污染性能,共混比(PVC和SPES的质量比)为8/2时综合性能最佳。     

化纤应用及处理

20011279PU/P vC共混多孔膜性能的研究Chu Caiguan.…;J.China Text.Univ.,1998,15(3),P .14(英)本文研究了涂层织物的PU/PVC共混膜的结构与性能。试验结果表明PU/PVC共混膜是多重孔性的结构,共混膜的结构与性能随PVC含量而变化。论文列出膜的性能与PVC含量的关系。(林求德)涂层膜聚氮醋聚抓乙烯 20011280用于制作中空纤维膜离子交换器的最佳组件腔的制备Muller Egbert…;J.Mol.Reeognit.,1998,11,(1-6),p .273一275(英)大孔聚酞胺6中空纤维可通过三个步骤完成聚合物涂层:首先,使氨端基与含双键的二官能试剂反应;其次,用不同的…     

聚氯乙烯/热塑性聚氨酯中空纤维膜的研制及应用

以聚氯乙烯(PVC)和热塑性聚氨酯(PUR-T)为原料,制备了PVC/PUR-T共混中空纤维膜,研究了铸膜液浓度、PVC与PUR-T配比、铸膜液添加荆、纺丝温度对PVC/PUR-T共混中空纤维膜性能的影响.结果表明,PVC/PUR-T配比为80:20,其质量分数为15%～16.5%,添加剂为PEG 600,纺丝温度为90%:时制取的PVC/PUR-T共混中空纤维膜性能较好.     

相转化法制备聚氨酯/高纯铜粉微孔膜及性能研究

在聚氨酯(PU)中添加高纯铜粉(Cu),以N,N'-二甲基甲酰胺(DMF)为溶剂,采用相转化法制备了聚氨酯/高纯铜粉(PU/Cu)微孔膜。通过膜动力学测试仪、扫描电子显微镜(SEM)、热重分析仪(TGA)、毛细流孔径仪及电子万能试验机对PU/Cu微孔膜的结构和各项性能进行了研究。结果表明:加入Cu后,PU膜的热稳定性、成膜速率、力学性能、亲水性、透气性均有一定程度的改善,膜孔结构得到细化,孔隙率和吸湿率呈先减小后增大的趋势。综合各项性能,当Cu添加量为1.0%时,PU/Cu微孔膜的整体性能最好。     

Improvement of filtration performance of polyvinyl chloride/cellulose acetate blend membrane via acid hydrolysis

Based on the hydrophilicity and biodegradability of cellulose acetate (CA), polyvinyl chloride (PVC)/CA blend membrane was prepared by solution comixing and phase transformation method. Then the CA in the blend membrane was partially hydrolyzed under acidic conditions to improve the hydrophilicity of the blend membrane, so as to improve the filtration performance of the PVC/CA blend membrane. The properties of the membranes were systematically characterized by Fourier transform infrared spectroscopy, differential scanning calorimeter, and scanning electron microscopy (SEM). The porosity, water contact angle, pure water flux (PWF), protein retention rate, and mechanical properties of the membrane were measured, and the effect of hydrolysis on the filtration performance of the blend membrane was analyzed. The results showed that the hydrophilicity and porosity of the blend membrane increased, the PWF and protein rejection rate enhanced after acid catalyzed hydrolysis, while the mechanical properties of PVC membrane were maintained. This simple preparation method endows PVC/CA blend membrane with desirable filtration performance, and also helps to overcome the disadvantages of poor hydrophilicity and easy pollution of pure PVC membrane.     

Fabrication and characterization of silk fibroin powder/polyurethane fibrous membrane

The blend fibrous membranes with the different mass ratio of silk fibroin (SF) powder to polyurethane (PU) were fabricated by electrospinning. The structure, morphology, mechanical properties, and surface wettabilities of the blend fibrous membrane are characterized by field‐emission scanning electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetry, dynamic mechanical thermal analysis, tensile testing, and contact angle measurements. The results show that the SF was uniformly distributed in the blend fibers. The mass ratio of SF to PU played an important role in influencing the structure and morphology of the blend fibers, and the optimum mass ratio was 5/5. With the increase in SF content in fibers, the fraction of SF in the surface of the SF/PU blend fibers and the crystallinity degree of PU increased, and the molecular orientation of PU along the fiber axis took place. The SF content regulated the hydrophilicity property of the membrane. The thermal stability and the dynamic storage modulus of the fibrous membrane decreased, and the phase separation between soft and hard segments of PU increased. Similarly, the stress at peak and Young's modulus of the fibrous membrane decreased gradually; the strain at peak first increased and then decreased. POLYM. ENG. SCI., 52:2025–2032, 2012. © 2012 Society of Plastics Engineers     

Effect of alumina nanoparticles on the antifouling properties of polycarbonate-polyurethane blend ultrafiltration membrane for water treatment

In this work, the flexibility of polycarbonate (PC) membrane was improved by using polyurethane (PU) additive. However, due to the hydrophobic nature of the PU polymer, alumina (Al₂O₃) nanoparticles were incorporated to PC-PU blend membrane. The prepared membranes have been used in a submerged membrane system to eliminate humic acid molecules from polluted water in both the presence and absence of coagulant (polyaluminum chloride). The obtained results showed that introduction of PU into PC membrane diminished hydrophilicity and enhanced porosity. Moreover, the flexibility of the PC membrane remarkably improved. Introduction of 1.5 wt% Al₂O₃ to the PC-PU blend membrane led to enhancement in both porosity and hydrophilicity. Results of morphological studies showed that in the presence of Al₂O₃ nanostructures, finger-shaped voids seemed to elongate across the entire thickness of the prepared membrane. Atomic force microscopy images showed that incorporation of PU and Al₂O₃ to the PC membrane resulted in a smoother surface. The antifouling performance of membranes revealed that the PC-PU/Al₂O₃ nanocomposite membrane possessed the most favorable antifouling features owing to its lowest surface roughness as well as highest hydrophilicity. For all membranes utilizing coagulant (PAC), the irreversible fouling ratio and the flux recovery ratio significantly diminished and increased, respectively.     

Thermal stability of poly(vinyl chloride)/polyurethane blends

The thermal stability of poly(vinyl chloride) (PVC) and thermoplastic polyurethane (PU) blends has been studied in this work. It has been found that the PVC/PU blends possess lower thermal stability than unmodified PVC. No effect of the structure of polyurethanes or their content on the stability of PVC/PU system has been found.     

Effect of plasma treatment of silk fibroin powder on the properties of silk fibroin powder/polyurethane blend film

In this study, silk fibroin powder was treated by dielectric barrier discharge (DBD) plasma. The objective is to improve the performance of the silk fibroin powder/polyurethane (PU) blend film used in biomechanical field. The scanning electron microscope (SEM) showed that the plasma‐treated powder was broken into small particles and the film from the treated powder became homogeneous and dense. Fourier transform infrared spectroscopy (FTIR) revealed that the hydrophobic groups in silk fibroin powder were oxidized during plasma treatment. Little change in chemical composition was found on the surface of the blend film from plasma‐treated powder. The fracture strain of the blend film from plasma‐treated powder was remarkably raised, whereas its tensile strength was influenced significantly by the plasma treatment conditions. The wet‐out time of the plasma‐treated powder/PU film was shortened considerably. This indicates the improved hydrophilicity of the blend film. In addition, the decreased values of water vapor permeability suggested that the structure of the blend film became dense. This might result from the strong interfacial adhesion between plasma‐treated powder and PU. POLYM. ENG. SCI., 50:1705–1712, 2010. © 2010 Society of Plastics Engineers     

Performance evaluation of polyvinylchloride/polyacrylonitrile ultrafiltration blend membrane

Polyvinylchloride (PVC) membranes were modified by blending with polyacrylonitrile (PAN) as a second polymer. The miscibility of PVC/PAN blend was examined using an incompressible regular solution (CRS) model in no need to make a membrane. The results showed that the PVC/PAN blend was immiscible for all compositions at a temperature range of ?25 to 225 °C. Furthermore, the prediction of the phase behavior of a PVC/PAN/DMF ternary system showed that the blend of two polymers was highly incompatible even in their common DMF solvent. However, this incompatibility led to a remarkable increase in the porosity of the blend membrane and pure water flux compared to those for pure PVC membrane. The pure water flux of the PVC membrane (37.9 ± 1.5 L/m² h) increased about 41 and 76% by adding 10 and 20 wt% PAN, respectively. The blend membranes also showed an enhanced flux recovery ratio (FRR) compared to a pure PVC membrane, although the PVC membrane rejection for Bovine serum albumin (BSA) was decreased after blending with PAN. The PVC/PAN (90/10) blend membrane was subjected to hydrolysis with NaOH alkaline solution at three different concentrations and contact times to further enhance its performance. The membrane, which was hydrolyzed with a 0.5 mol/L NaOH solution for 0.5 h, showed a highest pure water flux of 75.6 ± 7.2 L/m² h due to its increased hydrophilicity. This membrane also revealed an improved FRR and better thermal and mechanical properties compared to an unmodified membrane.     

Compatibility of poly(vinyl chloride) and polyurethane blends

The compatibility and the mechanical properties of the blends of polyurethane (PU) elastomer and poly(vinyl chloride) (PVC) were studied. The results showed partial compatibility between PU and PVC. When the portion of PVC in blends exceeded 75%, the compatibility decreased. On the other hand, increasing the molecular weight of the glycol in PU improved the compatibility. The elongation decreased and the Young's modulus increased as the proportion of the weight of PVC in blends was increased. The tensile strength reached a minimum when PU/PVC was 50/50.     

PVC／EC共混物的研制及其性能表征

采用溶液共混法和液一固相转化法（L-S）制备了聚氯乙烯与乙基纤维素共混物（PVC／EC）作为高效液相色谱（HPLC）柱填料。用黏度法、折光指数法、DSC法、FTIR法研究了PVC与EC的相容性；HPLC法表征该共混物的性能。实验结果表明，PVC与EC有良好的相容性；PVC／EC的亲水性和对不离解的极性有机物分离效率优于纯PVC，PVC／EC（80：20）合金适合作脱盐和脱糖的膜材料。