Chapter 22-4PlasticEngineering
Chapter 2 2-4 Engineering Plastic
Engineering Plastics High Strength Good Toughness Good Thermo propertiesExamples of Engineering Plastics:·PC·PAPA6 PA66·ABS·POM
Engineering Plastics • High Strength • Good Toughness • Good Thermo properties Examples of Engineering Plastics: • PA PA6 PA66 • PC • ABS • POM
Nylons(Polyamides)HnHThenameNylonwasgivenbytheDuPontCompanyofAmericatotheirfirst syntheticcondensation polymer formed by the reaction ofdifunctional acids with difunctional amines.Hence Nylons are also called polyamides. It hadbeen made as part of the fundamental programof W. H. Carothers to investigate the whole topicofpolymerization
Nylons (Polyamides) The name Nylon was given by the Du Pont Company of America to their first synthetic condensation polymer formed by the reaction of difunctional acids with difunctional amines. Hence Nylons are also called polyamides. It had been made as part of the fundamental program of W. H. Carothers to investigate the whole topic of polymerization
Carothers
Carothers
Nylons are one of the most common polymersused as a fiber. Because of the characteristicamide groups in the backbone chain of Nylons,it is usually used to replace Protein fiber , suchas the silk. The very first nylon product was atoothbrush with nylon bristles. Nylon's first realsuccess came with its use in women's stockings,inabout 1940.O—CH2-CH-CH-CH2-C—NH—CH-CH2-CH-CH2-CH2-CH-NH+,amidegroup
Nylons are one of the most common polymers used as a fiber. Because of the characteristic amide groups in the backbone chain of Nylons, it is usually used to replace Protein fiber , such as the silk. The very first nylon product was a toothbrush with nylon bristles. Nylon's first real success came with its use in women's stockings, in about 1940
SynthesizationNylons can be made from diacid chlorides anddiamines. Nylon 6/6 is made from themonomers adipoyl chloride and hexamethylenediamine.0NH2+H2N0hexamethylene diamineadipoyl chlorideHHOnylon6,6
Synthesization Nylons can be made from diacid chlorides and diamines. Nylon 6/6 is made from the monomers adipoyl chloride and hexamethylene diamine
SynthesizationHNHHOH0hexarmnethylenediamineadipic acidHH9nylon 6,6
Synthesization
SynthesizationAnother kind of nylon is nylon 6. It is made by aring opening polymerizationfrom the monomercaprolactam.0H0→←CH-CH-CH2-CH2-CH2-C-N+Hnylon 6s-caprolactam
Synthesization Another kind of nylon is nylon 6. It is made by a ring opening polymerization from the monomer caprolactam
StructurePolyamides are linear polymers with repeatingamide linkages along their chain. The amidegroups are strong polar, and can form hydrogenbond with each other. Because of this, andbecause the nylon backbone is very regular andsymmetrical, nylons are often crystalline, andmake very good fiber
Structure Polyamides are linear polymers with repeating amide linkages along their chain. The amide groups are strong polar, and can form hydrogen bond with each other. Because of this, and because the nylon backbone is very regular and symmetrical, nylons are often crystalline, and make very good fiber
Propertyhigh strength (especially at high temperatures)tensile, and flexural strengths from freezingtemperatures up to 300 oF , high tough at lowtemperatures, good impact, stiffnessexcellentfatigueresistanceabrasion resistant ,low coefficient of frictiongood electrical resistivitiesgood chemical resistance against organic solventsand alkalis,but are easily attacked by acids andoxidizing agentsretain useful mechanical properties over a range oftemperatures from -60~400 oF
Property ◼ high strength (especially at high temperatures), tensile, and flexural strengths from freezing temperatures up to 300 oF , high tough at low temperatures, good impact, stiffness ◼ excellent fatigue resistance ◼ abrasion resistant ,low coefficient of friction ◼ good electrical resistivities ◼ good chemical resistance against organic solvents and alkalis,but are easily attacked by acids and oxidizing agents ◼ retain useful mechanical properties over a range of temperatures from –60~400 oF