Substrate membrane poly

Researchers found that NAD serves as a substrate in poly(ADP-ribose) synthesis, a reaction important for DNA repair processes. In addition, it takes part in mono (ADP-ribosyl)ation reactions that are involved in endogenous regulation of many aspects of signal transduction and membrane trafficking in eukaryotic cells. 

A diamine solution in water and a diacid chloride solution in hexane are prepared. A porous substrate membrane is then dipped into the aqueous solution of diamine. The pores at the top of the porous substrate membrane are filled with the aqueous solution in this process. The membrane is then immersed in the diacid chloride solution in hexane. Because water and hexane are not miscible, an interface is formed at the boundary of the two phases. Poly condensation of diamine and diacid chloride will take place at the interface, resulting in a very thin layer of polyamide. The preparation of composite membranes by the interfacial in situ polycondensation is schematically presented in Fig. 3. 

Another method of preparing nanofiltration membranes is to dip-coat a thin layer of sulfonated poly(phenylene oxide) (SPPO) [17], sulfonated polysulfone (SPS) [18], or carboxylated polysulfone [19] on a porous substrate membrane. The sulfonic acid groups in SPPO and SPS also become negatively charged with -SO3 groups upon dissociation. Sulfonic acid is a stronger acid than carboxylic acid. 

Membranes for vapor removal from air have a structure similar to the Prism membrane, but they are prepared on a different principle [22]. Aromatic poly(etherimide) is used to produce a porous substrate membrane by the dry-wet phase inversion method. This polymer was chosen over polysulfone/poly(ether sul-... 

Microporous polyethylene (PE) membranes with various pore diameters and porosities and microporous polytetrafluoroethylene (PTFE) membrane were used as substrates for the plasma graft polymerization (Table II). Besides these porous substrates, homogeneous poly[ l-(trimethyl si lyl)-l-propyne] (PTMSP), which has the highest gas permeability among polymeric materials, was used as the substrate. The poly[l-(trimethylsilyl)-l-propyne] was synthesized from l-(trimethylsilyl)-l-propyne according to the literature procedure (19). Films were prepared by casting polymers from toluene solutions. Hereafter, the respective substrate membranes will be abbreviated as shown in Table II. 

We fabricated an MEA using pore-filling electrolyte membranes and measured their fuel cell performance in PEMFC operation using pure hydrogen gas as a fuel. The membrane was prepared using a cross-linked polyethylene (CLPE) film as Ihe porous substrate and poly(aciylamide J rJ-butyl sulfonic acid) (AXES) as Ihe filling electrolyte. 

The substrate membrane was then derivatized by the permeation of a 5% solution (v/v) of silane 3-glycidoxypropyltrimethoxysilane (GOPS) in o-xylene, toluene, or hexane through the membrane under convective flow at 25°C-60°C for 2 h. Polyamino acid (poly-L-aspartic acid [PLAA] and poly-[a,p]-DL-aspartic acid [PDAA], Mw 6-36 kD) was then reacted to the expoxy end group with 100 mL of a 100 mg/L aqueous solution at pH 92-9.5. The reaction scheme is given as follows ... 

These types of separators consist of a solid matrix and a liquid phase, which is retained in the microporous structure by capillary forces. To be effective for batteries, the liquid in the microporous separator, which generally contains an organic phase, must be insoluble in the electrolyte, chemically stable, and still provide adequate ionic conductivity. Several types of polymers, such as polypropylene, polysulfone, poly(tetrafluoroethylene), and cellulose acetate, have been used for porous substrates for supported-liquid membranes. The PVdF coated polyolefin-based microporous membranes used in gel—polymer lithium-ion battery fall into this category. Gel polymer... 

Osada et al. [52] have also grafted PMAA to a porous substrate in order to achieve an environmentally sensitive membrane. This sensitivity was termed a chemical valve function because mechanochemical forces caused the pores to enlarge and contract. PMAA was grafted onto poly(vinyl alcohol) (PVA) films which had a mean pore radius of 4 pm. The water permeation of the membrane was strongly affected by the conformational state of the PMAA grafts. At low pH the chains were contracted and the water permeability was... 

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