Resistance to organic chemicals

Compressed asbestos 250 General resistance to organic chemicals... 

More resistant to organic chemicals (e.g. carbon tetrachloride) than PS. Resistant to staining and to alkalis, acids (not... 

PP has lower specific gravity than other plastic materials. Having broad resistance to organic chemical ingredients, they are used in consumer products. The total environmental impact of PP and other thermoplastic materials is less than traditional materials in life-cycle analysis. Commercial PP is a complex mixture of varying amounts of isotactic, syndiotac-tic, and atatic polymers with a given MWD. 

They exhibit excellent dielectric properties over a wide range of frequencies and temperatures. PPE/ PS alloys are supplied in flame-retardant, filled and reinforced, and structural foam molding grades. PPE can also be alloyed with polyamide (nylon) plastics to provide increased resistance to organic chemicals and better high-temperature performance. 

The high crystallinity of acetal resins contributes significantly to their excellent resistance to most chemicals, including many organic solvents. Acetal resins retain their properties after exposure to a wide range of chemicals and environments. More detailed data are available (14). 

Chemical Resistance. Table 2 shows the chemical resistance of PVA fiber (40). The fiber exhibits markedly high resistance to organic solvents, oils, salts, and alkaU. In particular, the fiber has unique resistance to alkaU, and is hence widely used in the form of a paper principally comprising it and as reinforcing material for cement as a replacement of asbestos. 

As is apparent from the above information, there is no ideal disinfectant, antiseptic or preservative. All chemical agents have their limitations either in terms of their antimicrobial activity, resistance to organic matter, stability, incompatibility, irritancy, toxicity or corrosivity. To overcome the limitations of an individual agent, formulations consisting of combinations of agents are available. For example, ethanol has been combined with chlorhexidine and iodine to produce more active preparations. The combination of chlorhexidine and cetrimide is also considered to improve activity. QACs and phenols have been combined with glutaraldehyde so that the same effect can be achieved with lower, less irritant concentrations of glutaraldehyde. Some... 

The complexity of the new insecticidal chemicals brings many other problems. Synthetic organic chemicals are not effective against all pests. There is a marked selectiveness in action even between closely related species of insects. Some insects have already developed resistance to some of the newer materials. The idea of insects developing resistance to certain chemicals is not new. The over-all principle is well established in a few cases. The early development of flies resistant to DDT, a chemical which had been highly and universally effective for fly control, came as a surprise. Other cases of resistance to DDT are being indicated, and at least one kind of mite has developed resistance against another of the newer chemicals—parathion. 

Polyesters are, in general, organic solvent resistant. They show excellent room temperature resistance to organic solvents, such as hydrocarbons, alcohols, and chlorinated hydrocarbons. At slightly elevated temperatures of approximately 60 °C, alcohols and aromatic solvents can damage the polymer. Strong acids and bases can cause chemical damage to polyesters, as can ketones and phenols. 

It has an excellent outdoor life period and good strength. It is amorphous because of the presence of bulky side groups in the molecules. It is resistant to many chemicals but soluble in organic solvents like ketones, chlorinated hydrocarbons and esters. It can be thermally depolymerised to give back the entire quantity of monomer. 

Optical fibers which were developed primarily for the communication industry have been successfully implemented into other disciplines such as chemistry, physics, and biomedicine. Mass production of high-quality fibers by a variety of manufacturers has rendered themrelatively inexpensive. The use of optical fibers is rapidly increasing because of their size, cost, and easy mode ofoperation.(62) Table 7.1 shows properties of some commercially available optical fibers. Originally, optical fibers were made of glass but more recently they have become available as organic polymers or metal halides. They are flexible, stable, and resistant to many chemicals. Furthermore, optical fibers can improve safety by allowing the remote analysis of potentially harmful chemicals. A detailed review of the development of optical fibers has been previously published/63 ... 

Using the knowledge of the development of resistance to synthetic chemicals, one can predict that an organism encountering a new inhibitory NP in its food source, or in its environment, will evolve a capacity to adapt to the new chemical. By behavioural choices, or by chance circumstances, some individuals in the population will not be exposed to a lethal dose of the NP and the descendants of those individuals will eventually form resistant populations. 

Brand and Type Approximate Vapor Pressure (mm, at room temp.) Application Approximate Usable Range (°C) Resistance to Organic Solvent Vapors Chemically Attacked by... 

Nickel is resistant to organic acids dilute ammonium hydroxide (<2%) and to chlorination or fluorination. These alloys 200 and 201 are used in petrochemical, chemical industry, food industry and in the production of synthetic fibers. 

Resistance of Fibers to Organic Chemicals, Du Pont Bull. (1966) X-215. 

Chemical Resistance. Plastics are generally superior to metals in resistance to aqueous inorganic environments. Their resistance to organic solvents depends mainly on crystallinity and difference in polarity nonpolar polymers are more resistant to polar organics, while polar polymers are more resistant to nonpolar organics. 

PVOH (or tradename PVAL) is a crystalline, white powder soluble in water and alcohols. It is characterized by water solubility, low gas permeability barrier, high resistance to organic solvents other than alcohol, and crystallinity when stretch oriented. Crystallinity allows the material to polarize light. A series of hydrolysis levels of the plastic are available that range from room temperature solubility to those not soluble at all. The major applications of the PVOHs are in elastomeric products, adhesives, films, and finishes. Extruded PVOH hoses and tubing are excellent for use subjected to contact with oils and other chemicals. PVOH is used as a sizing in the manufacture of nylon. 

Chemical resistance is also one of the unique features of SPS. APS originally had good resistance to acids, alkalis and hydrolytic environments below Tg. SPS took over these chemical resistances from APS and acquired resistance to higher temperatures above Tg and, furthermore, resistance to organic solvents... 

Polyamine-cured epoxy systems have reasonable colour and colour retention, improved physical properties and good chemical resistance. They are, however, moisture sensitive, relatively toxic and have poor resistance to organic acids. Examples of this class are diethylene triamine (DETA) and triethylene tetramine (TETA). 

Generally, the adhesive/membrane is resistant to organic and inorganic acids, bases and salts in solution at various concentrations and temperatures (within the recommended range). The actual chemical resistance may depend on the specific environment of the application. The adhesive/membrane is not resistant to strong acids or petroleum-derived compounds though the block by itself is resistant to them. In such exposures, the compatible mortar must be used. 

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