Waterproof Membrane Thermoplastic processing
PVDF products processing methods
PVDF can be processed by general thermoplastic processing methods such as extrusion, injection molding, pouring, molding and transfer molding.
High molecular weight PVDF melt strength is better, can be extruded into a thin film, sheet, tube, rod and power insulation sleeve, etc., according to the equipment used and processed products shape, temperature control in the 210 ~ 290 degrees Celsius, the molding temperature control between 180 ~ 240 degrees Celsius, must strictly control the temperature can not make the temperature over its long-term melting temperature. Extrusion molding equipment can choose the general screw extruder.
(2) injection molding
Low molecular weight PVDF melt flow rate is high, can be spray injection molding processing methods for processing, generally use general injection molding machine, but the cylinder plunger, nozzle, etc. must be corrosion-resistant Ni-based alloy.
PVDF is configured as a solid content of 20% solution, casting on the aluminum foil, after 205 ~ 315 degrees Celsius hot melt, the water quenching can be made into a thick 0.05 ~ 0.075mm Continuous tough film,
In general, PVDF pellets are preheated in an oven or preheating furnace, preheating at a temperature of 215 to 235 degrees Celsius, and the preheated material is then added to a preheated 180 to 195 ° C mold at 14 MPa Pressure, holding pressure, holding time depends on the time required for melting and flow. Thick-walled products must be cooled to 90 degrees Celsius below the pressure to stripping, in order to avoid the product produced a bubble or deformation of the vacuum.
(5) transfer molding
Generally the first use of extruder plastic, and then the material transported to the storage tank, through the piston pump to the material in the storage tank into the mold, and pressure cooling. Whether it is molding or transfer molding, mainly used to produce larger, thick wall thickness of the product.
(6) other processing methods
Processing PVDF can also be impregnated, co-extruded, in line with the processing technology.
PVDF transfer membrane
PVDF is a high-strength, corrosion-resistant material, usually used to make water pipes. PVDF membranes can bind proteins and separate small fragments of proteins that were originally used for protein sequencing because the nitrocellulose membrane degrades in the Edman reagent, so PVDF is sought as a substitute, although the PVDF membrane binds The efficiency of the protein is not high for the nitrocellulose membrane, but because of its stability, corrosion resistance makes it ideal for protein sequencing and has been used for so far. PVDF membrane and nitrocellulose membrane, can be a variety of staining and chemiluminescence detection, but also a wide range of applications. This PVDF membrane, sensitivity, resolution and protein affinity in the fine process than the conventional membrane are high, very suitable for low molecular weight protein detection.
However, the use of PVDF membrane before, must first pretreatment with anhydrous methanol, and then in the transfer buffer can be used in a good balance (PVDF membrane with methanol bubble is designed to activate the PVDF film above the positive groups, making it easier With a negatively charged protein). After pretreatment of PVDF membrane in the transfer film, you can use without methanol transfer buffer. The use of NC film, and some need to use anhydrous methanol treatment, and some do not have to use a good transfer buffer balance can be a good.
Lithium iron phosphate battery with acetone dissolved PVDF (polyvinylidene fluoride) when the effect is not good.
sixteen. PVDF Piezoelectric Film Synthesis Method
Vinylidene fluoride as raw materials from polymerization. PVDF piezoelectric film is prepared by dissolving PVDF resin in dimethylformamide, prepared into 1% ~ 10% solution, purified by defoaming after casting method, placed in vacuum drying, made of 150μm thickness Of the film. By means of uniaxial oriented stretching, the molecular chain is oriented at a high degree of orientation, and the orientation orientation is fixed to exhibit a β-type crystal phase.
Seventeen. PVDF Piezoelectric Film Performance
PVDF is an organic piezoelectric material, also known as piezoelectric polymer. The advantages of such materials and their materials are flexible, low density, low impedance and high voltage voltage constant (g), etc., and the development is very rapid, the application of underwater acoustic ultrasonic measurement, pressure sensing, ignition detonation and so on. The disadvantage is that the piezoelectric strain constant (d) is so low that it is greatly limited as an active emission transducer.