The mainThe main properties of PTFE hydraulic seals

Modified polytetrafluoroethylene

Hydraulic seal rigidity of Teflon polytetrafluoroethylene its dynamic sealing effect, above a certain compression stress, will have a "cold" (creep), so that the sealing application has been greatly restricted. Therefore, the modified PTFE, to further improve its overall performance is the focus of the study.

Currently, mainly modified polytetrafluoroethylene composite or other materials on its surface treatment, the use of properties of the composite, PTFE make up their own deficiencies. Modified main methods are: surface modification, filling modification, blending modification.

Surface Modification

Hydraulic seals Teflon PTFE low surface energy, the critical surface tension of about 1.85 × 10-4N / cm, 1/3 equivalent of water contact angle 118 °, the largest of a variety of materials. Surface modification, PTFE surface to generate a lot of activity of free radicals for the next graft or adhesive to create the conditions. Surface Modification of PTFE under H2 plasma conditions is shown in Fig. Hydraulic seals PTFE surface of the plasma created under conditions other active hydroxyl radical, it is easy to change by grafting a surfactant PTFE suppress surface of inert PTFE.

Filled

PTFE obtained excellent wear resistance of the sealing material. Domestic and bronze powder, graphite, molybdenum disulfide (MoS2), glass fibers, carbon fibers, polyphenylene, rare earth, polyimide and nano materials as filler modifier modified PTFE. Hydraulic seals greatly improved wear resistance, creep resistance is improved to meet the specific seal under normal conditions. Fillers may be used alone, it can also be several filler composite applications. Table 1 is filled PTFE composites of several physical properties.

Blending

The use of PTFE hydraulic seals and other high performance engineering plastics modification, can combine the strengths of each component of the blend, and the complementary advantages, thereby widening the application fields of the material. Appropriate surface treatment must be carried out before making modification, or add the appropriate specific component in the process of modification in order to improve the compatibility of PTFE and other polymers.

The basic principle of blending is compatible with the principle of similarity, the degree of tolerance parameters similar principle, similar to the principle of surface tension. According to these three principles, to improve PTFE blended with other polymers compatibility from PTFE considerations:

(1) In order to improve the compatibility of PTFE and rubber, from the viewpoint of thermodynamics, the low molecular weight PTFE conducive compatible with the other polymer blends. In addition, the low molecular weight PTFE easily penetrate to the surface, increasing the self-lubricating material surface.

(2) of the PTFE special treatment surface improve compatibility with other polymers.

(3) the use of PTFE fine powder d, increasing the entropy of mixing. Typically less than 50nm particles.

Filled PTFE sealing material has excellent resistance to high temperature characteristics, excellent abrasion resistance, is the alternative to the traditional asbestos gasket materials main alternatives. The invention solves the expanded polytetrafluoroethylene PTFE elastic insufficient defects and compressive strength more than doubled, but also possesses good chemical resistance, insulation resistance, high temperature and other advantages of PTFE. The overall performance is any kind of sealing material are incomparable, is ideal for advanced sealing material. properties of PTFE hydraulic seals

Modified polytetrafluoroethylene

Hydraulic seal rigidity of Teflon polytetrafluoroethylene its dynamic sealing effect, above a certain compression stress, will have a "cold" (creep), so that the sealing application has been greatly restricted. Therefore, the modified PTFE, to further improve its overall performance is the focus of the study.

Currently, mainly modified polytetrafluoroethylene composite or other materials on its surface treatment, the use of properties of the composite, PTFE make up their own deficiencies. Modified main methods are: surface modification, filling modification, blending modification.

Surface Modification

Hydraulic seals Teflon PTFE low surface energy, the critical surface tension of about 1.85 × 10-4N / cm, 1/3 equivalent of water contact angle 118 °, the largest of a variety of materials. Surface modification, PTFE surface to generate a lot of activity of free radicals for the next graft or adhesive to create the conditions. Surface Modification of PTFE under H2 plasma conditions is shown in Fig. Hydraulic seals PTFE surface of the plasma created under conditions other active hydroxyl radical, it is easy to change by grafting a surfactant PTFE suppress surface of inert PTFE.

Filled

PTFE obtained excellent wear resistance of the sealing material. Domestic and bronze powder, graphite, molybdenum disulfide (MoS2), glass fibers, carbon fibers, polyphenylene, rare earth, polyimide and nano materials as filler modifier modified PTFE. Hydraulic seals greatly improved wear resistance, creep resistance is improved to meet the specific seal under normal conditions. Fillers may be used alone, it can also be several filler composite applications. Table 1 is filled PTFE composites of several physical properties.

Blending

The use of PTFE hydraulic seals and other high performance engineering plastics modification, can combine the strengths of each component of the blend, and the complementary advantages, thereby widening the application fields of the material. Appropriate surface treatment must be carried out before making modification, or add the appropriate specific component in the process of modification in order to improve the compatibility of PTFE and other polymers.

The basic principle of blending is compatible with the principle of similarity, the degree of tolerance parameters similar principle, similar to the principle of surface tension. According to these three principles, to improve PTFE blended with other polymers compatibility from PTFE considerations:

(1) In order to improve the compatibility of PTFE and rubber, from the viewpoint of thermodynamics, the low molecular weight PTFE conducive compatible with the other polymer blends. In addition, the low molecular weight PTFE easily penetrate to the surface, increasing the self-lubricating material surface.

(2) of the PTFE special treatment surface improve compatibility with other polymers.

(3) the use of PTFE fine powder d, increasing the entropy of mixing. Typically less than 50nm particles.

Filled PTFE sealing material has excellent resistance to high temperature characteristics, excellent abrasion resistance, is the alternative to the traditional asbestos gasket materials main alternatives. The invention solves the expanded polytetrafluoroethylene PTFE elastic insufficient defects and compressive strength more than doubled, but also possesses good chemical resistance, insulation resistance, high temperature and other advantages of PTFE. The overall performance is any kind of sealing material are incomparable, is ideal for advanced sealing material.