HIGH-TEMPERATURE HIGH-LINEAR-PRESSURE MICRO-EUTECTIC METHOD FOR ENHANCING STRENGTH OF POLYTETRAFLUOROETHYLENE (PTFE)-BASED MEMBRANE

Abstract

A high-temperature high-linear-pressure micro-eutectic method for enhancing a strength of a polytetrafluoroethylene (PTFE)-based membrane is disclosed. The method comprises the following steps: pushing a PTFE-based nano functional composite membrane forwards at a speed of 6-8 m/min in a high-temperature high-linear-pressure micro-eutectic cavity with a length of 1.5 m at a temperature of 380° C., controlling a linear pressure of a surface of the PTFE-based membrane to be 50-80 N/m, and under a coiling traction of a membrane coiling roller outside the cavity, enabling membrane molecular chains to shrink and generate eutectic phases, wherein multiple micro-eutectic molecular structures are arranged in parallel, and the PTFE-based nano functional composite membrane has a density of 2.1 kg/m.sup.3 and has nanoscale macromolecular aggregates and a nano-scale and micron-scale concave-convex geometrical ultra-micro-structure morphology with a surface average size of 10-20 .Math.m, a height of 5-10 .Math.m and a spacing of 10-20 .Math.m.

Claims

1. A high-temperature high-linear-pressure micro-eutectic method for enhancing a strength of a polytetrafluoroethylene (PTFE)-based membrane, comprising the following steps: pushing a PTFE-based nano functional composite membrane forwards in a high-temperature high-linear-pressure micro-eutectic cavity at a temperature of 70-420° C., controlling a linear pressure of a surface of the PTFE-based membrane to be 50-80 N/m, and under a coiling traction of a membrane coiling roller outside the cavity, and enabling membrane molecular chains to shrink and generate eutectic phases, wherein multiple micro-eutectic molecular structures are arranged in parallel, micro-pores between the membrane molecular chains become nano-scale and ultra-micron-scale, a color of obtained PTFE-based nano functional composite membrane after the micro-eutectic changes from opaque milky white to transparent color with high and uniform transparency, and the obtained PTFE-based nano functional composite membrane has nanoscale macromolecular aggregates and a nano-scale and micron-scale concave-convex geometrical ultra-micro-structure morphology with a surface average size of 10-20 .Math.m, a height of 5-10 .Math.m and a spacing of 10-20 .Math.m.

2. The high-temperature high-linear-pressure micro-eutectic method for enhancing a strength of a PTFE-based membrane according to claim 1, wherein the PTFE-based nano functional composite membrane is pushed forwards in the high-temperature high-linear-pressure micro-eutectic cavity at a speed of 6-8 m/min.

3. The high-temperature high-linear-pressure micro-eutectic method for enhancing a strength of a PTFE-based membrane according to claim 1, wherein the PTFE-based nano functional composite membrane has a density of 2.1 kg/m.sup.3.

4. The high-temperature high-linear-pressure micro-eutectic method for enhancing a strength of a PTFE-based membrane according to claim 1, wherein the high-temperature high-linear-pressure micro-eutectic cavity has a length of 1.5 m.

5. The high-temperature high-linear-pressure micro-eutectic method for enhancing a strength of a PTFE-based membrane according to claim 1, wherein the method comprises the following steps: pushing a PTFE-based nano functional composite membrane forwards at a speed of 8 m/min in a high-temperature high-linear-pressure micro-eutectic cavity at a temperature of 380° C., controlling a linear pressure of a surface of the PTFE-based membrane to be 60 N/m, and under a coiling traction of a membrane coiling roller outside the cavity, enabling membrane molecular chains to shrink and generate eutectic phases, wherein multiple micro-eutectic molecular structures are arranged in parallel, micro-pores between the membrane molecular chains become nano-scale and ultra-micron-scale, the color of obtained PTFE-based nano functional composite membrane after the micro-eutectic changes from opaque milky white to transparent color with high and uniform transparency, and the obtained PTFE-based nano functional composite membrane has nanoscale macromolecular aggregates and a nano-scale and micron-scale concave-convex geometrical ultra-micro-structure morphology with a surface average size of 10-20 .Math.m, a height of 5-10 .Math.m and a spacing of 10-20 .Math.m.

Description

DETAILED DESCRIPTION

[0014] The example provides a high-temperature high-linear-pressure micro-eutectic method for enhancing a strength of a PTFE-based membrane, wherein the method comprises the following steps: pushing a PTFE-based nano functional composite membrane forwards at a speed of 8 m/min in a high-temperature high-linear-pressure micro-eutectic cavity with a length of 1.5 m at a temperature of 380° C., controlling a linear pressure of a surface of the PTFE-based membrane to be 60 N/m, and under a coiling traction of a membrane coiling roller outside the cavity, enabling membrane molecular chains to shrink and generate eutectic phases, wherein multiple micro-eutectic molecular structures are arranged in parallel, the PTFE-based nano functional composite membrane has a density of 2.1 kg/m.sup.3, micro-pores between the membrane molecular chains become nano-scale and ultra-micron-scale, the color of the membrane after the micro-eutectic changes from opaque milky white to transparent color with high and uniform transparency, and the PTFE-based nano functional composite membrane has nanoscale macromolecular aggregates and a nano-scale and micron-scale concave-convex geometrical ultra-micro-structure morphology with a surface average size of 10-20 .Math.m, a height of 5-10 .Math.m and a spacing of 10-20 .Math.m.

[0015] 5 PTFE-based membrane samples obtained in the method are subjected to various performance tests and the results are as follows: (1) the membrane has an average thickness of 100 .Math.m; (2) the membrane has an average weight of 210 g/m.sup.2; (3) the membrane has a peel force of 50 N and a 180° peel strength of 1,000 N/m; (4) the membrane has an average tensile strength of 25 Mpa before and after aging and an average elongation rate of more than 90%, and shows no aging by a xenon lamp aging test, a freeze-thaw cycle performance test (a temperature of -60° C. to 150° C. and a humidity of 5-98%), an ozone aging test, an ultraviolet aging test and an artificial atmosphere corrosion and sea salt solution soaking test for 14,400 h; (5) the membrane does not have a rough surface and is free of damage to expose a substrate after 37 times/min of reciprocating friction for 40,000 times using a method in GB/T 9266-2009 “Determination of scrub resistance of film of architectural paints and coatings”, and thus has a strong abrasion resistance; (6) a dynamic wind pressure test platform is used to simulate a wind speed of 36.9 m/s (12-grade typhoon) to carry out a dynamic wind pressure test on a rain wash resistance, and the membrane does not have a rough surface and has an excellent rain erosion resistance after subjected to a strong-wind-speed water-blowing test for 1,000 h; (7) after tested by a scanning electron microscope (SEM), the surface morphology of the membrane shows micron-scale micro concave-convex surface structures with an average size of 20-40 .Math.m, a height of 10-20 .Math.m and a spacing of 30-50 .Math.m uniformly distributed in a warp and weft direction; (8) a contact angle of water drops on the surface of the membrane measured by a water contact angle tester is between 115.89°-125.46°; and (9) an average membrane surface roughness measured by a surface roughness meter is 0.18 .Math.m.

[0016] In conclusion, the present disclosure solves a problem that the PTFE and polyester composite membrane cannot be directly pasted on surfaces of wind turbine blades with an adhesive. The PTFE is prepared into a membrane material with a multi-nano-scale and micron-scale concave-convex geometrical ultra-micro-structure morphology. A low surface tension of solids and a high lubricating non-adhesive performance of the PTFE are combined to form a PTFE nano functional composite membrane with double functions of preventing adhesion and preventing and removing ice. The composite membrane is pasted on the surfaces of the wind turbine blades, improves a peel strength, can be used for anti-icing of various types of the wind turbine blades, and can really resist icing of rain and snow on the surfaces of the wind turbine blades. The method enhances an integral structural strength of the PTFE-based nano functional composite membrane. Therefore, the PTFE-based nano functional composite membrane used in the blade surfaces of various wind turbine generators has a higher abrasion resistance, corrosion resistance and aging resistance, the integral surface strength of the blades is enhanced, the integral bearing capacity and the erosion capacity of foreign objects of the blades are improved, and potential safety hazards of blade aging, cracking and the like are eliminated. The method can be directly used in preparing the PTFE-based membrane material for preventing marine fouling organism adhesion of steel pipe piles of offshore wind power and offshore platforms, snow accumulation and icing-preventing high-voltage transmission towers and snow accumulation and icing-preventing of (stayed-cable and suspension) bridges.

[0017] The disclosure may have other implementations in addition to those described above. All technical solutions formed by equivalent replacements or equivalent transformations should fall within the protection scope of the present disclosure.