Polyvinylidene fluoride membranes

FIG. 20-67 Chemical phase inversion 0.45- lm polyvinylidene fluoride membrane. Courtesy Millipore Corporation.)... 

Because membrane filtration is the only currently acceptable method of sterilizing protein pharmaceuticals, the adsorption and inactivation of proteins on membranes is of particular concern during formulation development. Pitt [56] examined nonspecific protein binding of polymeric microporous membranes typically used in sterilization by membrane filtration. Nitrocellulose and nylon membranes had extremely high protein adsorption, followed by polysulfone, cellulose diacetate, and hydrophilic polyvinylidene fluoride membranes. In a subsequent study by Truskey et al. [46], protein conformational changes after filtration were observed by CD spectroscopy, particularly with nylon and polysulfone membrane filters. The conformational changes were related to the tendency of the membrane to adsorb the protein, although the precise mechanism was unclear. 

N.C. nitrocellulose membrane. PVDF polyvinylidene fluoride membrane. 

After electrophoresis, proteins are transferred onto a nitrocellulose or PVDF (polyvinylidene fluoride) membrane, which is immersed in a solution of a selected antibody capable of combining with the target protein. Then the reaction of antigen-specific antibody is detected through a second antibody which is tagged enzymatically. Special attention must... 

Immobilon (polyvinylidene fluoride) membrane from Millipore Corp., Bedford, MA. 

This technique is still evolving. The favored approach at present is to submerge a small, known amount of suspension inside a secured Durapore (polyvinylidene fluoride) membrane pouch (Millipore Products, Bedford, MA) of suitable porosity in teabag fashion in a suitable dissolution medium using the USP Method 1 Paddle Apparatus. Optimization of experimental conditions (rate of agitation, volume and type of medium, temperature, etc.) must be established to achieve reproducible results. 

In recent years, improved methods of harvesting pellicle has been introduced that combine mechanical and chemical removal [39, 41], The tooth surface is either swabbed with a polyvinylidene fluoride membrane filter soaked in 0.5 M sodium bicarbonate [39] or rubbed with a foam sponge soaked with 2% sodium dodecyl sulphate solution [41], Using these collecting methods, new data on the composition of the pellicle have been obtained [15, 39,41,46,47]. 

Figure 6. Type III Structure of Polyvinylidene Fluoride Membrane Formed at Low Cooling Rates and Higher Polymer Concentrations (503X)...

Figure 9. Type IV Structure of Polyvinylidene Fluoride Membrane at Higher Magnification (5,000X compare Figure 8)...

Chemically resistant self-cleaning filtration membranes — Grafting of NIPAAm and dimethyl acrylamide onto polyvinylidene fluoride membranes to prepare chemically resistant self-cleaning membranes and drying membranes. 

DEGEN, PETER J. LEE, JOSEPH. Positively Charged Polyvinylidene Fluoride Membrane. US Patent 5,282,971 (1994). 

Fluorodyne Filter. [Pall Coip.] Hydrophilic polyvinylidene fluoride membrane filter. 

In the last decade, some manufacturers have been able to produce "bubble-pointable" (45-50 psi) pleated cartridges. These include "tortuous-pore" nylon and polyvinylidene fluoride membranes. The 0.2 ju cartridges show quantitative retention of Pseudomonas diminuta at challenge levels of 1010 to 1013 organisms. 

Polyvinylidene fluoride membranes these membranes, consisting of dihalogen fluoroalcane, have good temperature, chemical and physical stability. 

Khayet, M. and Matsuura, T. 2001. Preparation and characterization of polyvinylidene fluoride membranes for membrane distillation. Ind. Ene. Chem. Res. 40 5710-5718. 

Treating a microporous polyvinylidene fluoride membrane with ammonia or a mixture of nitrogen and hydrogen, Muller and Oehr (1999) were able to introduce some amine groups on the surface, but their amount was not correlated with the total surface-bound nitrogen. 

Yang, C.R., Jia, Z.D., Guan, Z.C. et al. 2009. Polyvinylidene fluoride membrane by novel electrospinning system for separator of Li-ion batteries. J. Power Sources 189 716-720. 

R. Zavaleta, F. P. McCandless, Selective permeation through modified polyvinylidene fluoride membranes, J. Membr. ScL, 1, 333-353 (1976). 

BOT Bottino, A., Camera-Roda, G., Capanelli, G., and Munari, S., The formation of microporous polyvinylidene fluoride membranes by phase separation, J. Membrane ScL, 57, 1, 1991. 

Lin T-E, Cortes-Salazar E, Lesch A, Qiao L, Bondarenko A, Girault HH (2015) Multiple scanning electrochemical microscopy mapping of tyrosinase micro-contact printed Iruit samples on polyvinylidene fluoride membrane. Electrochim Acta. 179 57-64. doi 10.1016/... 

A. Xu, A. Yang, S. Young, D. de Montigny, and P. Tontiwachwuthikul, Effect of internal coagulant on effectiveness of polyvinylidene fluoride membrane for carbon dioxide separation and absorption. Journal of Membrane Science 311 (2008) 153-158. 

M. Sugihara, M. Fujimoto, and T. Uragami. (1979). Effect of casting solvent on permeation characteristics of polyvinylidene fluoride membranes, Polym. Prepr., Am. Chem. Soc., Div. Polym. Chem. 20 999-1008. 

Khayet, M. and T. Matsuura. 2001. Preparation and Characterization of Polyvinylidene Fluoride Membranes for Membrane Distillation. Industrial Engineering Chemistry Research AQ(2A) 5710-5718. doi 10.1021/ie010553y. 

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