Chemical resistance also polyolefins

Nylon 11 is also used in powder form in spraying and fluidised bed dipping to produce chemical-resistant coatings. Although more expensive than the polyolefin and PVC powders, it is of interest because of its hardness, abrasion resistance and petrol resistance. 

Chlorinated polyether is formulated particularly for products requiring, good chemical resistance. Other materials exhibiting good chemical resistance include all of the fluorocarbon plastics, ethylpentenes, polyolefins, certain phenolics, and diallyl phtha-late compounds. Additives such as fillers, plasticizers, stabilizers, colorants, and type catalysts can decrease the chemical resistance of unfilled plastics. Certain chemicals in cosmetics will affect plastics, and tests are necessary in most cases with new formulations. Temperature condition is also very important to include in the evaluation. Careful tests must be made under actual use conditions in final selection studies. 

Chemical test. Solubility is a very effective test to identify fibers. Polyolefins have excellent chemical resistance to most common solvents, and they can be easily distinguished from a polyester or nylon fiber by a simple solubility test. Functional groups can also be identified using a technique such as FTIR which wiU help identify the fiber type. 

Polymethylpentene has a high crystalline melting point of 240°C, coupled with useful mechanical properties at 204°C and retention of form stability to near the melt point. However, the polymer is brittle (fiber or rubber additives are usually advised for improved toughness), ages poorly (the use of antioxidants is recommended), has high gas permeability, and is relatively expensive. Polymethylpentene s chemical resistance is very good and typical of the polyolefins. Its transparency is close to the theoretical optimum for thermoplastics. Polymethylpentene also has excellent electrical properties with power factor, dielectic constant, and volume resistivity on the same order as PTFE fluorocarbon. 

Polymethylpentene n Thermoplastic stereoregular polyolefin obtained by polymerizing 4-methyl-1-pentene based on dimerization of propylene having low density, good transparency, rigidity, dielectric and tensile properties, and heat and chemical resistance. Processed by injection and blow molding and extrusion. Used in laboratory ware, coated paper, light fixtures, auto parts, and electrical insulation. Also called PMP. 

Polyisobutylene consists of saturated hydrocarbons, so that PIB exhibits a chemical resistance similar to that of other polyolefins because of its non-polar character. It has excellent resistance to water, aqueous solutions of inorganic salts and alkalis and acids unless they are also oxidants. Due to its non-polar character, polyisobutylene dissolves at room temperature in aliphatic, aromatic, and chlorinated hydrocarbons. Polyisobutylene is degraded by halogens and strong oxidants [32]. Table A.7 (Appendix) compiles the chemicals resistance of PIB. 

It is interesting to note that properties such as light weight, energy absorption, or thermal insulation, related to the cellular structure, are used in many of the applications of these materials, fii addition, other characteristics that are connected to the polyolefinic character of the base material, such as low water absorption and low water transmission, chemical resistance, nontoxici-city, skin friendliness, and thermoformability are also used. 

Polypropylene is another member of the polyolefin family. It is a semicrystalline thermoplastic material whose blend of properties leads to a wide variety of applications, ranging from commodity use to specialty engineering. While it offers reasonably good mechanical properties, it also offers exceptional chemical resistance at a relatively low cost. 

The synthesis of new polymeric materials having complex properties has recently become of great practical importance to polymer chemistry and technology. The synthesis of new materials can be prepared by either their monomers or modification of used polymers in industry. Today, polystyrene (PS), which is widely used in industrial applications as polyolefins and polyvinylchlorides, is also used for the production of plastic materials, which are used instead of metals in technology. For this reason, it is important to synthesize different PS plastic materials. Among the modification of PS, two methods can be considered, viz. physical and chemical modifications. These methods are extensively used to increase physico-mechanical properties, such as resistance to strike, air, or temperature for the synthesizing of new PS plastic materials. 

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