Chemical resistance of PES

The value of polymer part wear in acid is roughly of the same order as in air. The behavior of wear curves of the polymer samples during dry friction is attributed to frictional transfer (curves 4 -6 ) in which case the curves are arranged in order of material strength the strongest non-modified PE wears less. Impregnation of the mineral oil and Cl improves chemical resistance of PE and it therefore wears less (curves 5 and 6) than the pure PE (curve 4). 

Sulfone-based polymers offer a number of features that make them attractive for a wide variety of applications. Several attributes of interest include excellent thermal stability, toughness, resistance to hydrolysis, inherent flame retardance, and clarity. PSF, PES, and PPSF exhibit many similar characteristics and therefore can be used interchangeably in a number of applications. In such cases, PSF is most commonly used due to its lower cost. There are applications that take advantage of the higher thermal performance or chemical resistance of PES. In addition, many applications are made possible by the excellent hydrolytic stability, chemical resistance, flame resistance, and supertough behavior of PPSF. Several application areas are described in some detail below. 

Table A.33 Chemical resistance of PES, PSF und PPSF SC stress cracking test, FT tensile test (s ) soluble, (a ) soluble see Tables 5.95 - 5.96 type of test and testing conditions were provided by [863], no test type or testing conditions were provided by [1039]...

Table 15.23. Comparison of the chemical resistance of PA-6, PPE/PA-6, PE/HIPS and PC (% change in properties )...

Fluorination. Fluorination surface treatment improves the resistance of PE to nonpolar solvents. A barrier is created by the chemical reaction of the fluorine and the PE, which forms a thin (20-40 mm) fluorocarbon layer on the bottle surface. Two systems are available. The in-process system uses fluorine as a part of the parison expand gas in the blowing operation. A barrier layer is created only on the inside. In the post-treatment system, bottles are placed in a chamber filled with fluorine, and a barrier layer forms on both inside and outside surfaces. 

Polycarbonate can be blended with polyethylene (PE). Bloiding PC with PE has found many uses with a combination of a high level of heat resistance and dimensional stability as well as noncorrosive properties and ease of moldabihty. It is deficient in its tendency to craze and crack under the effects of contact with organic solvents such as gasoline. The failure mechanism of a crazed PC would be brittle fracture ratha- than ductile fracture. Blending PC with low density polyethylene (LDPE) and with linear low density polyethylene (LLDPE) or with ethylene propylene diene monomer (EPDM) rubbo improves the chemical resistance of the product to solvents. 

Substitution of F for H in the C-H bond substantially increases the bond strength from 99.5 kcal/mole for the C-H bond to 116 kcal/mole for the C-F bond. Consequently, thermal stability and chemical resistance of PTFE are much higher than PE because more energy is required to break the C-F bond. Additionally, the size of the F atom and the length of the C-F bond... 

Table 8. Resistance, of Natural (Unreinforced) PSF, PES, and PPSF Resins to Various Chemical Environments ...

Non-Metallic Materials Numerous engineering thermoplastics have been commercialised including materials such as polyetherether ketone (PEEK) and polyether sulphate (PES) with much improved thermal/chemical resistance. The usage of FRP equipment has increased, and fluoropolymer lining technology/applications have come of age. Of particular interest is the development of stoved, fluoropolymer coating systems for process industry equipment. 

Hitachi Chemical is considering developments of new applications for its crosslinked PE foam. It has been used as roofing material, cushioning and insulation. It is a closed-cell type and does not absorb moisture or water, is chemical resistant and highly shock absorbant. It is easy to handle and may be processed using conventional equipment. Applications are expected to widen to meet future needs. 

PS, PET, and PE as mentioned above, exhibit certain disadvantages in this aspect. On the other hand, since COCs are superior in transparency, heat resistance and chemical resistance, the use of them for various containers has been proposed (7). 

The preceding structural characteristics dictate the state of polymer (rubbery vs. glassy vs. semicrystalline) which will strongly affect mechanical strength, thermal stability, chemical resistance and transport properties [6]. In most polymeric membranes, the polymer is in an amorphous state. However, some polymers, especially those with flexible chains of regular chemical structure (e.g., polyethylene/PE/, polypropylene/PP/or poly(vinylidene fluoride)/PVDF/), tend to form crystalline... 

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