Polyvinyl fluoride mechanical properties

PVC, another widely used polymer for wire and cable insulation, crosslinks under irradiation in an inert atmosphere. When irradiated in air, scission predominates.To make cross-linking dominant, multifunctional monomers, such as trifunctional acrylates and methacrylates, must be added. Fluoropolymers, such as copol5miers of ethylene and tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), are widely used in wire and cable insulations. They are relatively easy to process and have excellent chemical and thermal resistance, but tend to creep, crack, and possess low mechanical stress at temperatures near their melting points. Radiation has been found to improve their mechanical properties and crack resistance. Ethylene propylene rubber (EPR) has also been used for wire and cable insulation. When blended with thermoplastic polyefins, such as low density polyethylene (LDPE), its processibility improves significantly. The typical addition of LDPE is 10%. Ethylene propylene copolymers and terpolymers with high PE content can be cross-linked by irradiation. ... 

Fluoropolymers, such as copolymer of ethylene and tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), are widely used in wire and cable insulations. They are relatively easy to process and have excellent chemical and thermal resistance, but tend to creep, crack and possess low mechanical stress at temperatures near their melting points. Radiation has been found to improve their mechanical properties and crack resistance.36... 

In practice, an attempt is made to equalize the properties of the PVF films in the machine and transverse directions. The excellent properties of the films have spurred the use of polyvinyl fluoride films in numerous outdoor and indoor applications where mechanical strength is important in addition to chemical resistance, durability, and continuous-use temperature range. 

Certain polymers, such as polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), possess special properties in the film form, caileApiezoelectricity and pyroelectricity. Piezoelectricity is electric polarization of a film produced by mechanical strain in some crystals. The polarization is proportional to the amount of strain and changes sign with it. The reverse is true and an electrical polarization induces a mechanical strain in piezoelectric sensors. Pyroelectricity is electric polarization of a film induced by thermal absorption in some polymer crystals. The induced polarization is proportional to the level of thermal change. These properties can be used in the manufacture of transducers, microphones, loudspeakers, pressure gauges, pickup heads, hydrophones, motion sensors, and other devices from biaxially oriented PVDF films. Table 13.37 gives the properties of a piezoelectric film of polyvinylidene fluoride. 

The compatibilizer improves the mechanical properties of PE/starch, and addition of a plasticizer is actually detrimental to the finished products. Although PE is used here to demonstrate the results of this invention, results are practically the same with other combinations of polymer and compatibilizer as disclosed therein. Incorporation of compatibiHzer is easily accomplished by mechanical blending of the polymer, starch, and compatibilizer prior to extrusion. Typically, the compatibilizer is composed of the same polymer as the primary polymer itself. The polymer component of the compatibilizer may be selected from the group consisting of polyethylene, polypropylene, polystyrene, polybutylene, poly(styrene-ethyl-ene-butylene-stryrene), poly(ethylene terephthalate), polyvinyl fluoride, polyvinyl chloride, or derivatives thereof [6]. 

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