Polysulphones applications

Although the nylons are not generally considered as outstanding electrical insulators, their toughness and, to some extent, their temperature resistance, have led to applications in coil formers and terminal blocks. Indeed, the new nylon 46 materials would appear to be of particular interest here. Acetal resins, polysulphones, modified PPO and polycarbonates, however, present a challenge to applications in this sphere. 

The transparent polyamides have increased significantly in importance in recent years. For transparent applications they are competitive with poly(methyl methacrylate), polycarbonates, polysulphones and MBS. In terms of toughness they are like polycarbonates, polysulphones and MBS and much better than the... 

The polysulphones tend to be used in applications when requirements cannot quite be met by the much cheaper polycarbonates and possibly aromatic polyethers. In many of the fields of use they have replaced or are replacing ceramics, metals and thermosetting plastics rather than other thermoplastics. 

A wide variety of thermoplastics have been used as the base for reinforced plastics. These include polypropylene, nylon, styrene-based materials, thermoplastic polyesters, acetal, polycarbonate, polysulphone, etc. The choice of a reinforced thermoplastic depends on a wide range of factors which includes the nature of the application, the service environment and costs. In many cases conventional thermoplastic processing techniques can be used to produce moulded articles (see Chapter 4). Some typical properties of fibre reinforced nylon are given in Table 3.2. 

Some component values of Tg are listed in Table 10.7. It can be easily checked that these values are widely applicable since they allow us to predict the Tg of linear polymers such as polycarbonate, polysulphones, phenoxy, etc. For example, for the polysulphone... 

Polysulphone (PSU) is a high-performance polymer with superior mechanical, electrical and thermal properties in a temperature region from -100 up to 180 °C. It is mainly used in exacting mechanical and electrical applications. 

A number of copolymers such as poly(butylene terephtalate)-poly(tetramethylene terephtalate)218,219), polysulphone-poly(dimethylsiloxane)220,221 polycarbonate-polysiloxane222-225), polyethylene-polypropylene226) and many others227-237) have been synthetized and studied. However, the respective papers are mainly aimed at application, and we shall not analyze them in the present review. 

Furthermore, as these devices are produced from organic materials (polysulphone fibres), samplers may add some OM to a sample. A recent study (Di Bonito, 2005) posed questions in these areas, and found that after several applications porosity would decrease because of a combination of wearing and organics building up. 

The hollow fibre is the most crucial part of the microdialysis probe. It acts as a membrane, and its characteristics affect performance in the sampling step as well as the probe s suitability for the selected application. Hollow fibres are commercially available in different materials, the most common being polycarbonate (PC), regenerated cellulose (Cuprophan, CU), cellulose acetate (CA), polyacrylonitrile (PAN), polyethersulphone (PES), polysulphone (PE), and polyamide (PA). Generally, the fibres have an outer diameter between 200... 

Relatively few applications can be found in this field that involve the coupling of microdialysis to biosensors, especially electrochemical ones. The major problem is always the need to exclude electrochemically active substances, which can be present in the external medimn, and, because of their low molecular weight, can easily cross the membrane of the microdialysis probe. Some attempts to overcome this problem have been reported by Csoregi [187], who coupled a microdialysis probe equipped with a polysulphone membrane with a 5000 Da cut-ofiF to a carbon paste electrode with wired GOD, thus excluding many interfering substances. Similarly, Rohm [188] has assembled a screen-printed biosensor for lactate based on an ultraviolet-polymerizable enzyme paste and then applied it in an FIA system for the on-hne monitoring of cell cultivation. 

Temperature stability is important for some applications of SILMs in gas separation, such as capture of CO from coal gasification plants. Ilcovich et al. [25] analysed the stability of a SILM based on [hmim+lfNTfj ] supported on a polysulphone organic membranes in the selective separation of CO from He at high temperature. This membrane was found to be stable up to 125 C, the failure of the membranes above that temperature being attributable to support failure rather than any effect on the ionic liquid. Recently, Myers et al. [32] reported operation of [hmim ][NTfj ] supported on nylon membranes up to 300 C. It was found that permeability in this [hmim [NTfj ] membrane increased with temperature while the selectivity decreased. 

Examples of resins used include the nylon family (polyamide/PA), polypropylene (PP), polystyrene, and polyethylene. There continues to be growing applications for the higher-performance RTFs, such as polyphenylene sulphide (PPS) and polysulphone (PSU). Use is made of many other TPs (Chapter 3). 

Poly ethersulphone. An amorphous thermoplastic with a chemical structure as shown in Figure 1.3. Transparent in its original form. Service temperature of end-products is up to approximately 180 °C. Examples of applications transparent parts of household articles and appliances, switches, hot water meter components, electronic parts. Trade name Victrex PES (UK). The industrial plastic polysulphone is also a poly-ethersulphone in the chemical sense. 

Polysulphone, Its chemical construction is illustrated in Fig. 1.3. A transparent thermoplastic in its original form. Service temperature of its products is up to about 150 °C. Resistant to hydrolysis (e. g. in repeated heat sterilization). Examples of applications transparent components of medical tools and instruments, electric switches, electronic parts. The industrial polysulphone is poly(ether-sulphone). Trade names Mindel (USA), Udel (USA). 

Tribological characteristics confirm the influence of sulfur modification of metal counter face on lowering fiiction for the metal-polymer couples studied. In the case of ebonite, the coefficient of friction reduced significantly for the whole experimental mn, whereas application of SBR vulcanizate or polysulfide rubber was effective only during the first period of experimental cycles. Any improvement of tribiological characteristics was not assigned for polysulphone. The polymer was observed to worn the surface of iron counterface, what resulted in increase of the coefficient of friction in this case. 

Because the thermal stability of polystyrenes and polymethacrylates is limited to 200°C, continuous use of a polymer-supported reactive species tends to be limited to significantly lower temperatures than this (see polymeric sulphonic acids). There is considerable interest in supporting, in particular, alkene oxidation catalysts on polymers and to operate reactions at temperatures above 200°C. To achieve this, novel thermo-oxidatively stable supports are required and some progress has been made in this direction. More details of specific applications will be given later, but supports based on, for example, polyacrylonitrile [50-52], polyamides [53-56], polysulphone [57, 58], polyaniline [59] and polybenzimidazole... 

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