Selective resins

There is not enough space here to give a detailed classification, but only to delineate the major families from which resins for industrial coatings may be selected. Resins may be divided into two groups according to their modes of film formation which may or may not involve a chemical reaction. In the first, the components must react together to form a crosslinked structure which may require heat, radiation or catalysis to effect the reaction. The bulk of resins used in industrial finishes are of this type. They are commonly referred to as chemically convertible or, simply, convertible. 

In this chapter we have explored the various methods by which polymer scientists characterize the molecular structure of polymers. Given the complex molecular distribution found in most polymers, the best that we can do in many cases is to measure some average value or distribution of values that represents the polymer. Armed with these values polymer scientists and engineers can design or select resins suitable for a myriad of practical applications. 

A sample of phosphonic acid resin Diaion CRP200 in wet Na+ form was kindly provided from Mitsubishi Chemical Co. Ltd. This wet resin sample was dried in vacuum, and then the resin with particle sizes of 60 - 32 mesh was selected by meshing. The selected resin was conditioned by treatment with 1 M HC1, water, 2 M NaOH, water, 1 M HC1, and water in successive. Finally, thus, the resin was changed into H+ form. The phosphorus content and acid capacity of the selected resin in the H+ form were measured according to the reported methods and were 4.6 mmol/g and 8.8 meq/g, respectively. Wet volume of the resin was 2.6 ml/g. Hereafter, this is abbreviated as CRP200 for simplicity. 

Kiss [8] examined various techniques for the efficient separation and preconcentration of boron from marine sediments. Alkaline fusion with potassium carbonate was used to render boron reactive, even in the most resistant silicate minerals. Fusion cakes were extracted with water and borate was isolated by Amberlite XE-243 boron-selective resin. Borate was determined spectrophotometrically, following elution with 2 mol L 1 hydrochloric acid. Either the carminic acid complex (620nm), formed in sulphuric acid (94%) or sulphuric acetic acid (1 4), or the azomethine hydrogen ion association complex (415nm) formed at pH5.2, were used for borate measurement. 

Table 2.3 Physical Properties and Applications for Selected Resins... 

The lateral stress ratio depends on the resin type and shape, surface treatments such as additives, temperature, and pressure. The ratio is measured using a compaction cell [2], as shown in Fig. 4.8. This cell is very similar to one shown in Fig. 4.3 except the piston for the lateral stress ratio cell is octagonal in cross section and a pressure sensor is mounted in the cylinder wall. The stress ratio is calculated by dividing the pressure measured at the side of the cylinder by the calculated pressure in the axial direction at the height of the sensor. The calculation method can be found elsewhere [2j. The lateral stress ratio for select resins at 25°C and 2.5 MPa are provided in Table 4.1. 

Table 4.1 Lateral Stress Ratio at 25 °C and 2.5 MPa for Select Resins [2]...

Table 4.2 Thermal Conductivities for Selected Resins, Steel, and Glass...

Figure 4.16 Melt densities for select resins as a function of temperature. PVC, PMMA, and PVDF resin data are from Zoller and Walsh [43]. All resins contain only extremely low level of additives...

Several of the most commonly used resins were studied at a screw and barrel temperature of 35 °C. As previously discussed, this temperature condition is comparable to the conditions in the feed casing or Section 1. This is just the start of solids conveying as conveying continues into Section 2 where the inside barrel wall temperatures are considerably higher. In order to visualize the contrast between the six different polymers tested, the solids conveying rates as a function of discharge pressure for these select resins are presented in Fig. 5.14. 

Figure 5.14 Comparison of the effect of exit pressure on solids polymer conveying for select resins. The screw and barrel were maintained at 35 °C...

Figure 5.18 Torque as a function of discharge pressure for select resins. The temperature of the barrel and screw were maintained at 35 °C. The screw speed was maintained at 50 rpm...

Figure 6.10 Reevaluation of the melting data for select resins from Tadmor and Klein [8] by Tang [31]...

Appendix A4 Shear Stress at a Sliding Interface and Melting Fluxes for Select Resins... 

Table A4.1 Data for Shear Stresses at a Sliding Interface for Select Resins in this Book...

Stresses at a siiding interface for select resins are shown in Figs. A4.1 through A4.8. Aii resins were commercially available when tested, and they contained only low levels of standard additives. 

ELECTRICAL PROPERTIES OF MATERIALS 593 Table 6.13 Some Electrical Properties of Selected Resins... 

In some cases, it was not possible to sewer the distillate, whose concentration was in excess of the limits laid down by Italian legislation. In these esses, the distillate was treated using specific selective resins in order to remove the metallic cyanide compounds. 

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