聚二甲基硅氧烷/溶剂体系气液平衡研究

采用气液色谱法测定了聚二甲基硅氧烷（ＰＤＭＳ）和９种溶剂在５８～１８０℃范围内,７个不同温度下无限稀溶剂活度系数和Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ相互作用参数。应用ＵＮＩＦＡＣ和ＵＮＩＦＡＣ－ＦＶ模型对ＰＤＭＳ／烃溶剂体系无限稀溶剂活度系数进行了估算。结果表明,ＵＮＩＦＡＣ－ＦＶ模型能较好地预测ＰＤＭＳ／烃溶剂体系无限稀溶剂活度系数。     

改性聚氯乙烯体系的脆／韧转变研究

用缺口冲击实验研究了ＣＰＥ、ＮＢＲ、ＤＯＰ、ＰＭＭＡ、ＰＳ等改性对ＰＶＣ脆／韧转变变温度的影响。实验表明，ＰＭＭＡ、ＰＳ等脆性塑料对ＰＶＣ具有不同于ＣＰＥ、ＮＢＲ等弹性体的改性机理，两者均可使ＰＶＣ体系的脆／韧转变温度发生变化。随改性剂含量的增加，用传统改性剂（ＣＰＥ、ＤＯＦＦ等）改性的ＰＶＣ体系的脆／韧转变变温度呈下降趋势，而脆性塑料则使体系的转变温度具有一低温度。     

PAN／PS共混中空纤维超滤膜研究

本文将聚丙烯腈（ＰＡＮ）和聚砜（ＰＳ）材料共混，采用二甲基甲酰胺（ＤＭＦ）作溶剂，以干－湿纺丝工艺制备中空纤维超滤膜，研究了二种膜材料和溶剂的热力学性质，确定合适的共混体系，并相同共混比下共混物浓度对中空纤维超滤膜性能影响。以磷酸三乙酯（ＴＥＰ）和冰醋酸作为添加剂，分别观测其不同含量膜性能变化规律。认为磷酸三乙酯作用添加剂有一定的优越性。提高铸膜液温度，有助于增强ＰＡＮ－ＰＳ－ＤＭＦ所组成部分互溶     

聚乙烯吡咯烷酮添加剂对聚醚砜制膜体系的影响

本文考察了不同ＰＶＰ／ＰＥＳ比率对ＰＥＳ／ＰＥＳ／ＰＶＰ／ＤＭＡｃ／Ｈ２Ｏ制膜体系热力学平衡关系、成膜动力学因子Ｄｅ以及膜分离性能的影响，揭示了亲水性聚合物添加剂ＰＶＰ在ＰＥＳ膜形成过程中所起的作用。结果表明：ＰＶＰ不是单纯的致孔剂，它改变了制膜液相平衡关系及浸入沉淀进非溶剂侵入速速度而延迟或促进相分离，从而影响了成膜的结构和分离性能。     

NH4Cl水溶液在成过程中的致孔作用

本文以ＮＨ４Ｃｌ饱和水溶液做添加剂，对ＰＶＤＦ／ＮＭＰ体系在成膜过程中的致孔作用做了研究。铸膜液中通ＮＨ４Ｃｌ水溶液加入量的改变，膜孔径也发生变化，并出现最大值。通过Ｘ－射线衍射扫描发现制膜液中存在无机盐时膜中无定形结构增加，表明无机盐的加入有助于膜孔形成。     

NH_4Cl水溶液在成膜过程中的致孔作用

本文以ＮＨ４Ｃｌ饱和水溶液做添加剂，对ＰＶＤＦ／ＮＭＰ体系在成膜过程中的致孔作用做了研究。铸膜液中随ＮＨ４Ｃｌ水溶液加入量的改变，膜孔径也发生变化，并出现最大值。通过Ｘ－射线衍射扫描发现制膜液中存在无机盐时膜中无定形态结构增加，表明无机盐的加入有助于膜孔形成     

西班牙生产聚偏氟乙烯复丝纱

西班牙Ｍａｎｒｅｓａ的纤维生产厂家ＰｏｌｉｓｉｌｋＳＡ，是世界上唯一生产聚偏氟乙烯（ＰＶＤＦ）复丝纱的生产厂家。ＳｏｌｅｆＰＶＤＦ适用于许多特殊的化学和石化应用领域，具有突出的耐无机和有机酸、氧化性环境、脂肪和芳香族烃类、醇类和含卤素溶剂特性。它还可耐卤素特别是澳和弱浓碱和碱金属。它在高度极性溶剂如丙酮和乙酸乙酯中会溶胀，在对质子有惰性的溶剂如ＤＭＦ和ＤＭＳＯ中略能溶解。ＳｏｌｅｆＰＶＤＦ在张力及挠曲、扭短或综合条件下的机械性能良好，ＬＯＩ为４４。Ｐａｌｉｓｉｌｋ还在’９９产业用纺织品展览会上展…     

PVF2／P（MM—St）共混体系的结晶性能和相容性的研究

用示差量热法（ＤＳＣ）、动态力学分析法（ＤＭＡ）和悬浮法测密度法研究了聚偏氟乙烯（ＰＶＦ２）／甲基丙烯酸甲酯与苯乙烯的无规共聚和［Ｐ（ＭＭＡ－Ｓｔ）］的共混体系的相容性和结晶性能。结果发现ＰＶＦ２／Ｐ（ＭＭＡ－Ｓｔ）共混体系是部分相容体系,其结晶性能随共混物中Ｐ（ＭＭＡ－Ｓｔ）的含量而变化,并就模压成型的热历史对该共混体系相容性的影响进行了讨论。     

净化废水用PVA水凝胶的开发：II.用含微生物的PVA凝胶处理废水中的N,N—二甲

用含二甲基甲酰胺（ＤＭＦ）的废水充分培养活性污泥，并将其截留和固定在球形ＰＶＡ水凝胶粒子上。测试了合成ＰＶＡ凝胶中细菌的数目和分布特征。分离出含杆（状）菌仙影掌属Ｄ－１的ＤＭＦ－分解细菌。提示出细菌各自的形态和生理反应。对经冷冻－融化制备的含ＤＭＦ－分离细菌的球形ＰＶＡ凝胶进行了ＤＭＦ－废水处理试验。经基础研究和小型试验结果表明稳定运行和连续操作的处理能力为１ｋｇ／ｍ＾３／天。     

NBR／EPDM共混橡胶

ＮＢＲ／ＥＰＤＭ共混橡胶《弹性体》１９９３，№１报导，北京化工学院利用商品化高聚物ＥＶＡ－１４作增容剂，制得了优异机械性能的ＮＢＲ／ＥＰＤＭ共混胶。胶料配方为：ＮＢＲ６０，ＥＰＤＭ３０，ＥＶＡ－１４１０，ＨＡＦ３０，ＤＢＰ１０，防ＲＤ１．０，ＺｎＯ５...     

Study on the control of pore sizes of membranes using chemical methods: Part III. The performance of carbonates and bicarbonates in the membrane-making process by the chemical reaction

In this paper, polyvinylidene fluoride (PVDF)/polymethyl acrilate (PMMA)/cellulose acetate (CA) blend UF membranes were prepared by chemical reaction introduced phase-inversion method. The results of the experiment show that: (1) The membrane pore size distribution is more uniform due to the presence of carbonates or bicarbonates in the coagulation bath; (2) No more than the stoichiometric ratio amount of carbonates or bicarbonates in the coagulation bath can effectively improve the membrane pore size distribution and make the pore size of membrane more uniform; (3) The membrane prepared by carbonates solution as a working solution in coagulation bath possess superior performance than that by bicarbonates.     

Effect of additives concentration on the surface properties and performance of PVDF ultrafiltration membranes for refinery produced wastewater treatment

The aim of this study was to investigate the effect of pore-forming hydrophilic additives on the porous asymmetric polyvinylideneflouride (PVDF) ultrafiltration (UF) membrane morphology and transport properties for refinery produced wastewater treatment. PVDF ultrafiltration membranes were prepared via a phase inversion method by dispersing lithium chloride monohydrate (LiCl·H₂O) and titanium dioxide (TiO₂) nanoparticles in the spinning dope. The morphological and performance tests were conducted on PVDF ultrafiltration membranes prepared from a different additive content. The top surface and cross-sectional area of the membranes were observed using a field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) analysis. The surface wettability of porous membranes was determined by the measurement of a contact angle. The mean pore size and surface porosity were calculated based on the permeate flux. The results indicated that the PVDF/LiCl/TiO₂ membranes with lower TiO₂ nanoparticles loading possessed smaller mean pore size, more apertures inside the membrane with enhanced membrane hydrophilicity. LiCl·H₂O has been employed particularly to reduce the thermodynamic miscibility of dope which resulted in increasing the rate of liquid–liquid demixing process. The maximum flux and rejection of refinery wastewater using PVDF ultrafiltration membrane achieved were 82.50 L/m² h and 98.83% respectively at 1.95 wt.% TiO₂ concentration.     

Preparation and performance of the novel PVDF ultrafiltration membranes blending with PVA modified SiO2 hydrophilic nanoparticles

In this study, PVA‐SiO₂ was synthesized by modifying silica (SiO₂) with polyvinyl alcohol (PVA), then a novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane was prepared by incorporating the prepared PVA‐SiO₂ into membrane matrix using the non‐solvent induced phase separation (NIPS) method. The effects of PVA‐SiO₂ particle on the properties of the PVDF membrane were systematically studied by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT‐IR), surface pore size, porosity, and water contact angle. The results indicated that with the addition of PVA‐SiO₂ particles in the PVDF UF membranes, membrane mean pore size increased from 80.06 to 126.00 nm, porosity improved from 77.4% to 89.1%, and water contact angle decreased from 75.61° to 63.10°. Furthermore, ultrafiltration experiments were conducted in terms of pure water flux, bovine serum albumin (BSA) rejection, and anti‐fouling performance. It indicated that with the addition of PVA‐SiO₂ particles, pure water flux increased from 70 to 126 L/m² h, BSA rejection increased from 67% to 86%, flux recovery ratio increased from 60% to 96%, total fouling ratio decreased from 50% to 18.7%, and irreversible fouling ratio decreased from 40% to 4%. Membrane anti‐fouling property was improved, and it can be expected that this work may provide some references to the improvement of the anti‐fouling performance of the PVDF ultrafiltration membrane. POLYM. ENG. SCI., 59:E412–E421, 2019. © 2018 Society of Plastics Engineers     

Stability of acrylic acid grafted poly(vinylidene fluoride) hollow fiber membrane prepared by high‐energy electron beam

In this article, poly(vinylidene fluoride) (PVDF) hollow fiber membrane and acrylic acid (AA) were co‐irradiated by high‐energy electron beam to introduce hydrophilic carboxylic groups on the membrane surface. Thermal capability, mechanical performance, pore size, and permeation property were investigated to determine the stability of the membrane pore structure before and after irradiation polymerization. The decomposition temperature, melting point, glass transition temperature, and breaking force of the PVDF‐g‐AA membrane increased slightly because of irradiation grafting polymerization. After 15 months of storage, the pore size distribution of the PVDF‐g‐AA membrane became smaller and more dispersive. The pure water flux and the rejection to bovine serum albumin of the PVDF‐g‐AA membrane increased significantly with the increase in hydrophilicity and decrease in pore size. The results indicated that the structure and properties of the PVDF hollow fiber membrane were stable after high‐energy electron beam irradiation grafting polymerization, even after 15 months of storage. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41165.     

Preparation of PVDF ultrafiltration membranes using PVA as pore surface hydrophilic modification agent with improved antifouling performance

Novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes were facilely fabricated using polyvinyl alcohol (PVA) aqueous solution as the coagulation bath through phase inversion method. In the process, PVA was introduced into the pore surfaces of the PVDF membranes via the interdiffusion of the non‐solvent water and the solvent. The effects of PVA content in the coagulation bath on membrane properties were systematically discussed. The results indicated that the increase of PVA content in coagulation bath resulted in the formations of the more sponge‐like structures and the higher surface hydrophilicity. Smaller pore size led to lower water flux and higher bovine serum albumin rejection. Fouling resistance measurement indicated that the membranes made in PVA/water coagulation bath had higher flux recovery ratio (92.1%) than the membrane made in a pure water bath (71.0%). Furthermore, mechanical property test revealed that the resulting membranes had high tensile strength and Young's modulus. In this work, we found that the morphology and the property of the novel PVDF membranes could be determined by the PVA content in the coagulation bath. POLYM. ENG. SCI., 59:E384–E393, 2019. © 2018 Society of Plastics Engineers     

等离子体改性聚偏氟乙烯超滤膜的研究

为了改善聚偏氟乙烯(PVDF)超滤膜的亲水性,采用等离子体技术对PVDF粉料进行功能化改性,使其表面带有功能化基团,以达到提高其水通量,进而改善抗污染能力的目的。实验结果表明:采用等离子体改性PVDF粉料,可以在PVDF粉料表面接上亲水性基团羟基和羰基,从而改善PVDF的亲水性。     

Synthesis and characterization of low content of different SiO2 materials composite poly (vinylidene fluoride) ultrafiltration membranes

A comparison of the morphology and performance of virgin poly (vinylidene fluoride) (PVDF) ultrafiltration (UF) membrane, and PVDF-composite membranes with low content of two different SiO₂ (N-SiO₂ and M-SiO₂ particles) was carried out. Cross-sectional area and surface morphology of the membranes were observed by scanning electron microscopy and atomic force microscopy. Surface hydrophilicity of the porous membranes was determined through the measurement of a contact angle. Performance tests were conducted on the composite membranes through water flux and bovine serum albumin (BSA) retention. Average pore size and surface porosity were calculated based on the permeate flux. Thermal stability and mechanical stability were determined by thermogravimetric analysis and tensile stress tests. The results indicate that N-SiO₂/PVDF (P-N) membranes possessed larger average pore size and porosity, which led to higher water flux and a slight decline in BSA retention. On the other hand, M-SiO₂/PVDF (P-M) membranes had better mechanical stability and anti-fouling performance with enhanced membrane hydrophilicity and decreased membrane surface roughness. Both of the P-N and P-M membranes exhibited typical asymmetric morphology and improved thermal stability.     

液液界面法测超滤膜孔径及孔径分布

本采用液液界面法，利用毛细管现象测定了截留分子量为２×１０＾４和５×１０＾４聚砜超滤膜ＰＳ－２，ＰＳ－５的孔径及孔径分布。结果表明，利用水－正丁醇体系能测定超滤膜的孔径及孔径分布，并且具有操作简便，测试压力接近膜工作压力的优点，对于ＰＳ－２超滤膜，测试压力达０．５ＭＰａ即能得到膜完整的孔径分布曲线。     

Synthesis of polyvinylidene fluoride (PVDF) membranes for protein binding: Effect of casting thickness

Microporous polyvinylidene fluoride (PVDF) membranes were synthesized from PVDF/N‐methyl‐2‐pyrrolidinone (NMP) solutions using an immersion–precipitation method with a 2‐propanol/water mixture as a soft coagulant. The effects of membrane thickness on pore size distribution and surface/cross‐section morphology were studied using capillary flow porometry and scanning electron microscopy (SEM), respectively. All the synthesized membranes had a small range of pore size distribution, with the pore size decreasing with increasing casting thickness. The semicrystalline PVDF membranes demonstrated significant variations in morphology under SEM observation, with the existence of polymer agglomeration at a casting thickness of 500 μm and above. The protein binding capacity was observed to be highest at a casting thickness of 400 μm, where optimum pore morphology provided a large surface area for protein binding. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

BPAC-UF组合工艺对微污染原水处理效果及膜污染控制

采用生物粉末活性炭-超滤(BPAC-UF)分体式工艺的中试装置,探究该工艺对西氿微污染原水的处理效果,在此基础上对比研究聚偏氟乙烯(PVDF)和聚氯乙烯(PVC)两种材质超滤膜的膜污染情况。PVDF膜和PVC膜两种不同材质的膜组合工艺对浊度去除率均超过95%,超滤膜可保证出水浊度要求。PVDF膜对尺寸不超过2μm的颗粒物去除效果要略优于PVC膜。初期PAC未转化为BPAC时,工艺对氨氮和CODMn的去除主要靠活性炭吸附。当PAC转化为BPAC,BPAC-UF对氨氮的去除主要是通过生物作用,后期去除率稳定在80%以上,BPAC-UF对CODMn去除率不高,稳定在25%左右。在膜污染控制方面,PVDF膜和PVC膜的跨膜压差增长趋势相似,但PVC膜的跨膜压差增速要略高于PVDF膜。经过强化物理反冲洗和化学反冲洗后,PVDF膜和PVC膜的产水性能均能恢复至较优状态,且PVDF膜恢复程度略优于PVC膜。