Tensile properties coatings

To determine the effect of coating thickness on tensile properties, coating thicknesses of 0.25, 0.5, 0.75, 0.85, 1.0, 1.25 and 1.5 im of Parylene-C were applied to modern silk fabric. In Table 2, the breaking-load and strain-to-break are shown as a function of coating thickness, and a linear dependence is evident. A similar effect was observed when paper was coated with Parylene-C (5). 

Tensile properties of importance include the modulus, yields, (strength at 5% elongation), and ultimate break strength. Since in many uses the essential function of the film may be destroyed if it stretches under use, the yield and values are more critical than the ultimate strength. This is tme, for example, where film is used as the base for magnetic tape or microfilm information storage. In some cases, the tensile properties at temperatures other than standard are critical. Thus if films are to be coated and dried in hot air ovens, the yield at 150°C or higher may be critical. 

Wire and cable insulation based on vulcanizates of PZ has also been studied. Again, low fire risk was the target property, and this was achieved. The need to vulcanize the coating, somewhat modest tensile properties, tensile strength of 5.2 to 12.2 MPa (760 to 1770 psi), and high dielectric constant (4—5 at 10,000 Hz) limited interest in this appHcation (19). 

The melting point of aluminium (660°C). The operating temperature usually reaches 750-850°C in pretreatment and 700°C in the bath, causing a loss in tensile properties of cold-drawn wire. On the other hand, if cold-worked material which is to be subsequently annealed is used in this process the annealing and coating operations may be combined, with obvious economic advantage. 

The metallurgical experiments showed that the beta-alpha transition of the tin coating did not occur at irradiation doses of 3-5 Mrad and 6-7.5 Mrad at 5, —30, and —90°C and that the tensile properties, impact ductility, peel strength of soldered lap joints, and microstructure of commercial tinplate and solder were not affected by the irradiation conditions that are used in the sterilization of meat products. 

Braiding hoses with wires to resist high burst pressures or for external protection is common, using a braiding machine. The wires used, usually of steel, will be either zinc- or brass-coated to achieve adhesion during vulcanisation. The gauge of the wire and its tensile properties will be matched to the expected service demands for the hose. 

Figure 15.4 gives the stress-strain diagrams for a typical fiber, plastic, and elastomer and the average properties for each. The approximate relative area under the curve is fiber, 1 elastomers, 15 thermoplastics, 150. Coatings and adhesives, the two other types of end-uses for polymers, will vary considerably in their tensile properties, but many have moduli generally between elastomers and plastics. They must have some elongation and are usually of low crystallinity. 

The tensile properties of the S-SBR/EPDM blends cured with the uncoated and coated sulfur are shown in Fig. 34. It is clear that the compounds with micro-encapsulated sulfur show largely improved tensile strength, elongation at break, and higher moduli. 

One of the more interesting initial differences between the tensile properties of coated and uncoated fabric, shown in Table 1, is the decrease in the initial modulus. The Parylene-C coating used in the majority of the tests, 0.75 Jim, was the smallest thickness at which a qualitative change in the handle of this type of fabric was noticed. 

Table 1. Tensile Properties of Coated and Uncoated Modern Silk Fabric...

Table 2. Tensile Properties of Parylene-C Coated silk...

Thermal Exposures. The thermally Induced changes in tensile properties of coated and uncoated silk fabric, expressed as percent retained breaking-load, strain-to-break and energy-to-break in Figures 2,3, and 4, respectively, are shown with the lines representing the calculated exponential decline. 

The effect of humidity variation on the color change of uncoated silk fabric at constant temperature (90°C) for a fixed exposure time (17 days) is shown in Figure 8. The rate of change in color increases with relative humidity above 50 % for both coated and uncoated fabric. This is the same humidity level above which the change in the tensile property degradation rates also increases. 

Initially, the tensile properties of Parylene-C coated silk cloth were higher than that of the uncoated cloth (with the exception of the initial modulus). However, after a 242 kJ exposure to the xenon-arc source, the magnitude of the tensile properties of both materials were the same. 

No significant difference in the degradation rate of tensile properties for either uncoated or coated silk was found on variation of the irradiance level of the xenon lamp from 0.28 W/m2 to 0.42 W/m (340 nm) for a constant total energy input of 86 kj (340 nm). Apparently, reciprocity holds in this range of irradiances. 

This behavior was not the same for Parylene-C coated, fabric which continued to yellow with irradiation and also continued to exhibit a decline in tensile properties to 242 kJ (340 nm). 

Effect of Parvlene-C Coating on Historic Silk Fabric. The results of tensile testing of coated and uncoated historic silk fabric are given in Table 5. For modern, strong silk (original, uncoated breaking-load >250 N, strain-to-break >15%), a 0.75 )Un thick layer of Parylene-C increased the tensile properties, with the exception of the initial modulus, as was shown in Table 1. 

Table 5. Tensile Properties of Uncoated and Coated Historic Silk...

Historic fabric samples that were further deteriorated by heat or light exposures prior to coating with Parylene-C showed the same trends increased breaking-load and initial modulus with no added strain-to-break. The absolute increase in breaking-load was small when compared with the increase that resulted when modern silk fabric was coated, but the percentage increase was higher due to the initially low absolute values of the tensile properties. 

The coating of Parylene-C did not have an effect on the thermal degradation rates of the silk broadcloth tensile properties or yellowing. The coating deteriorated when... 

Test Method for Impact Strength of Adhesive Bonds Test Method for Tensile Properties of Adhesive Bonds Test Methods for Pressure Sensitive Adhesive Coated Tapes Used for Electrical and Electronic Applications... 

South Korean company SK Chemicals produces SKYGREEN polybutylene succinate (PBS) thermoplastics based on aliphatic polyester and aliphatic/aromatic co-polyesters that were developed from SK Chemicals polyethylene terephthalate (PET) technology. SKYGREEN BDP products offer LDPE-like properties. They are used in films, disposable cutlery, food trays, hairbrush handles and paper coatings. Aliphatic versions biodegrade more rapidly and offer better processing and tensile properties than the aromatic-aliphatic grades, which cost less. 

The effect of irradiation dose and different polyfunctional monomers(PFMs) at a constant ratio of 10 phr on the physicochemical properties of a PVC formulation used as wire coating was investigated. The PFMs used were trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, pentaerythritol tetraacrylate, triallyl cyanurate and 1,6-hexanediol diacrylate. The properties studied included tensile properties at room and elevated temps., softening temp., swelling characteristics and volume resistivity. 18 refs. 

Mechanical Tensile Properties, measured according to ASTM D638 on 3-mil thick cured films of the conformal coating, are modulus of 1750 psi, tensile of 2000 psi, and elongation-at-failure of 285%. 

More recently, Kotek at al. studied the effects of untreated (denoted as Cl) and stearate-treated calcium carbonate particles (denoted as C2) of 1.3 p.m on the tensile properties of P-PP. Moreover, stearate-coated calcium carbonate particles of 0.075 p,m (denoted as C3) are also used (44). The p-nucleating agent employed is based on an amide of dicarboxylic acid. The critical concentration of p-nucleator needed to achieve 61% P-PP is 0.03 wt% on the basis of the XRD analysis. With further increase in the p-nucleator content to 0.1 wt% (supercritical), the p-PP content increases, but very slightly, to 65%. Furthermore, the K value also depends... 

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