Casting capillary tube

Complex 4 was melt-casted (sodium chloride plates) with concomitant homopolymerization at 200 °C for 36 h under a nitrogen atmosphere. Polymer 5 was insoluble in common organic solvents. Polymer 5 exhibited a Tm of 360 °C (sealed capillary tube) with no apparent signs of decomposition. 

Instead of using a planar molding master, a fused silica capillary tube (50 pm i.d. and 192 pm o.d.) was used as a template for casting PDMS channels, and as the fluid inlet/outlet tubes. After PDMS curing, the middle pre-scored section (4 cm) of the capillary was removed to reveal the PDMS channel (192 pm wide and deep) [817]. Similarly, a capillary was used to mold a PDMS channel, and to produce an electrospray emitter. In this case, after PDMS curing, the last 0.5-cm section of the capillary was removed to create a channel [821]. 

Films were fabricated by drop-casting the dye/sol mixture onto glass capillary tubes or glass coverslips. The chemical stractures of C481, TSPP and Pluronic P123 are shown in Fig. 1. 

It is found that these assumptions are only precise when the capillary tubing is rather small. In the case of larger sized capillaries, correction tables are found in the literature (Adamson and Cast, 1997). However, in some particular case where the contact angle, 0, is not zero, one will need a correction, and equation will become... 

Figure 2.1 Polymeric membrane shapes and cross-sectional structures. Tubular membranes are similar to flat sheet membranes because they are cast on a macroporous tube as support. Capillary membranes are hollow fibers with larger diameter, that is, >0.5 mm.

While the previously described three membrane modules required flat sheet membrane material for their preparation, special membrane configurations are needed for the preparation of the tubular, capillary, and hollow fiber modules. The tubular membrane module consists of membrane tubes placed into porous stainless steel or fiber glass reinforced plastic pipes. The pressurized feed solution flows down the tube bore and the permeate is collected on the outer side of the porous support pipe, as indicated in Figure 1.33 (d). The diameters of tubular membranes are typically between 1-2.5 cm. In some modules, the membranes are cast directly on the porous pipes and in others they are prepared separately as tubes and then installed into the support pipes. 

All of the tubes and hollow-fibers are self-supporting except for the PVDF membrane which is cast on the inside of a porous polypropylene tube. In most cases, they are potted on the ends to separate the process stream from the permeate (see Figure 2.54). This bundle of tubes or capillaries becomes the replaceable module. 

A method of preparing a capillary type CMS membrane was described in detail by Haraya et al. [9]. The schematic of the casting equipment is shown in Fig. 7.8. A 1.6 wt% solution of polyamic acid (PA) in dimethyl acetamide (DMAC) was used for the casting dope. A polytetrafluoroethylene (PTFE) tube (e.d. 1.8 mm) traveled through the polymer dope in a container at a speed of 3 cm/min, coming out through... 

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