Introduction of Fluoropolymer

Introduction
A fluoropolymer is a fluorocarbon-based polymer with multiple strong carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases.Fluoropolymer is usually olefinic polymer which consists of partially or fully fluorinated olefinic monomers such as vinylidene fluoride (CH2¼CF2) and tetrafluoroethylene (TFE) (CF2 CF2). These polymers have been covered in great detail in a number of references (see General Refer- ences). More specialty fluorinated polymers include per- fluoroethers, fluoroacrylates, and fluorosilicones which are used in significantly smaller volume than olefinic fluo- ropolymers.

History
In 1938, polytetrafluoroethylene (DuPont brand name Teflon) was discovered by accident by a recently hired DuPont Ph.D., Roy J. Plunkett. While working with tetrafluoroethylene gas, he noticed that a previously-pressurized cylinder had no pressure remaining. In dissecting the cylinder, he found a mass of white solid in a quantity similar to that of the tetrafluoroethylene gas. It was determined that this material was a new-to-the-world polymer. Tests showed the substance was resistant to corrosion from most substances and had better high temperature stability than any other plastic. By early 1941, a crash program was making commercial quantities.

Properties
Fluoropolymers share the properties of fluorocarbons in that they are not as susceptible to the van der Waals force as hydrocarbons. This contributes to their non-stick and friction reducing properties. Also, they are stable due to the stability multiple carbon–fluorine bonds add to a chemical compound. Fluoropolymers may be mechanically characterized as thermosets or thermoplastics. Fluoropolymers can be homopolymers or copolymers.

Typical properties
Property	Method No.	Units	PTFE	FEP	PFA	ETFE	ECTFE	PCTFE	PVDF
Specific gravity	D792	-	2.17	2.15	2.15	1.7	1.7	1.7	1.78
Yield strength	D638	MPa	10	12	15.5	24	31	40	46
Yield strength	D638	PSI	1,450	1,740	2,250	3,480	4,500	5,800	6,670
Elongation		%	200-500	250-350	300	200-500	200-300	80-250	20-150
Tensile modulus	D638	MPa	600	500	700	1500	1655	1500	2400
Tensile modulus	D638	ksi	87	72.5	101.5	217.5	240	218	348
Hardness	D2240	Shore D	60	57	62	75	75	90	79
HDT, @ 66 PSI	D648	°F	250	158	164	219	240	248	300
HDT, @ 264 PSI	D648	°F	122	129	118	160	169	-	239
Limiting oxygen index	D2863	%	>95	>95	>95	30-36
Dielectric constant	D150	1 MHz	2.1	2.1	2.1	2.6

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