This paper will present an overview of how polymer lining systems are developed in an era of constant change. Presented as ground breaking work, this paper will include information on how current suppliers evaluate new and modified polymers. Test methods used to determine the physical properties needed for a specific manufacturing process and how the industry evaluates newly introduced or modified material for the intended use will be given. A proposed steam cell test method for evaluation of high temperature fiuoropolymer lining laminate systems will be introduced.
One of the major challenges faced by corrosion engineers is the responsibility for selecting the most cost effective and environmentally sound materials for the safe handling of corrosive, hazardous, ultrapure or other aggressive fluids. This requires, in addition to direct experience, the will and the opportunity to keep current on the experience of others as shared at technical meetings and reported in the trade press. It also demands the mechanism for accumulating this data in a readily retrievable form.
Early in the decision making process, the choice may be made for you by temperature limitations, strength requirements, pressures, chemical resistance, abrasion resistance or other characteristics that automatically limits your selection to a specific metal, plastic or ceramic. In making this early decision, however, make sure your data are up to date. You may be surprised at the changed properties of the newer nonmetallic formulations which have extended their use at temperatures exceeding 300F or provided property values much beyond those of metals.
Since material selection is directly determined by the process conditions, the horse pulling the cart must get primary consideration. Your initial task involves def'ming the process conditions and selecting and specifying the appropriate material of construction. After selecting the correct material for the service, the desired manufacturing process must be selected. When considering thermoplastic polymer materials of construction, options that may be considered include coatings, thermoplastic sheet linings, dual laminate composites or rotationally molded or solid plastic fabrications.
Today, what complicates the material selection for the corrosion engineer considering plastics is the wide range of newly introduced thermoplastics, the introduction of copolymers and terpolymers of these materials and the various grades of materials being manufactured or modified for a particular manufacturing process or end use application.
This paper presems a description of the various polymers materials tested for use in industry to combat corrosion.
TYPES OF POLYMERS
Thermoplastics such as polyvinylchloride, polypropylene and polyethylene enjoy widespread use due to their dependability, availability and relatively low cost. Composite materials combine the chemical and temperature resistance of the polymers with the strength of reinforcements such as glass or carbon fibers. Lining laminates are manufactured with fabric backings to provide for bonding with adhesive systems such as elastomeric or thermoset epoxies. This allows for lining systems to be bonded to a wide variety of substrates such as steel, fiberglass, concrete and even wood.