![]() ![]() ![]() Also, as compound availability is customer-driven, lead times may vary. Microflex cannot certify the accuracy of the data and therefore does not represent nor warrant that the information in the chemical resistance chart is accurate or complete. ![]() The chemical resistance ratings are based on published research data. Therefore, it is important to consider all aspects of the compound prior to use. This Chemical Resistance Chart is offered as a guide and for reference purposes only. Every compound has specific characteristics and many compounds have common attributes. These elastomers form the base of a wide variety of compounds, designated for specific applications. This section contains descriptions of the elastomers used in seal applications. This is why thermoset (rubber) parts are generally preferred for sealing applications. Also, thermoset polymers possess superior mechanical, thermal, and chemical properties as well as better dimensional stability than thermoplastics. This process is reversible and repeatable, as opposed to thermosetting polymers where the process is irreversible. Conversely, a thermoplastic material will soften when heated (and eventually liquefy) and harden when cooled. Thermoset polymers become permanently "set" in the presence of heat and do not soften in the presence of subsequent heating. One classification method of polymeric materials is according to physical properties at elevated temperatures. What is the difference between a thermoset and thermoplastic? Determination of the amount of compression set is governed by ASTM designation D395 test procedure. Failure of the seal to return to its original shape after compression is the condition termed "compression set" and all seals exhibit some degree of compression set. What is compression set?Įlastic recovery is a measure of the elastomer's ability to return to its original shape once a compressive force has been removed. Once the rubber has been vulcanized or "cured", physical properties are enhanced and the compound is more resistant to deterioration. These vulcanizing agents (usually sulfur or peroxide) are necessary to facilitate chemical crosslinking of polymeric chains. The long, flexible polymeric chains of rubber, when heated, react with vulcanizing agents to form three-dimensional structures. Lubricants, colors or any other miscellaneous ingredients may also be added. Antidegradants, such as antioxidants and antiozonants, retard the deterioration of rubber products. Carbon black is one of the most common fillers because it reinforces the molecular structure. Sulfur is one of the most widely used vulcanizing agents to promote crosslinking which is used in conjunction with accelerators and accelerator activators to reduce cure times and enhance physical properties. Processing aids and softeners, such as oils and plasticizers, modify rubber to aid in mixing or molding operations. The elastomer is the basic component of all rubber recipes and is selected in order to obtain specific physical properties in the final product. Therefore, elastic rebound or rubbery behavior is possible due to contortions of long, flexible polymeric chains, which allows rubber to be so resilient. When a deformation of the rubber occurs, these tangled chains uncoil and recoil when the force is released. The polymeric chains in rubber tend to be very long and flexible by nature and can rotate about their axis, which results in an entangled mass of contorted chains. Why does rubber act "rubbery?"Ī polymer is considered a very viscous liquid or an elastic solid (i.e. For example, the addition of fillers can reinforce or modify properties, or additional plasticizer can increase elongation and lower durometer. Rubber is composed of many different ingredients that include the base elastomer, vulcanization agents, fillers and plasticizers. The base monomer or monomers is used to classify the type of rubber, for example: Nitrile, Silicone or Neoprene. Polymers are long molecular chains and are derived from the Greek "poly" (many) and "meros" (parts). "Rubber" refers to elastomeric compounds that consist of various monomer units forming polymers that are heat cured (vulcanized). All Rights Reserved.Basic Concepts of Rubber What is "rubber?" We do not warrant (neither express nor implied) that the information in this chart is accurate or complete or that any material is suitable for any purpose. We have no knowledge of possible effects beyond this period. Ratings of chemical behavior listed in this chart apply at a 48-hr exposure period. ALWAYS test your equipment under the specific conditions of your application before permanent installation. Please Note: The information in this chart has been supplied by reputable sources and is to be used ONLY as a guide in selecting equipment for appropriate chemical compatibility. Stainless Steel Chemical Compatibility Chart: Check the chemical compatibility of Stainless Steel with various chemicals, solvents, alcohols and other products.
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