PVDF (Average molecular weight of 534000)

Catalog Number	ACM24937799-3
CAS	24937-79-9
Structure
Molecular Weight	64.035
Molecular Formula	C2H2F2
Unit Size	1g/5g/25g

Case Study

Electrospinning of PVDF Nanofiber Membranes Achieves Controlled Crystalline Phase

Lei, Tingping, et al. Applied Physics A, 2015, 120, 5-10.

This work investigated heating treatments during or after electrospinning to determine effective methods to control the crystallization phase of PVDF nanofibers. The results showed that by adjusting the collector temperature and flow rate during the electrospinning process, or heating the electrospun nanofiber samples, PVDF nanofibrous membranes with α-, β-, or γ-phase as the main component can be obtained.
Preparation Procedure of PVDF Nanofibrous Membranes
· Polyvinylidene fluoride (Mw * 534,000) powder was dissolved in a mixture of N-methyl-2-pyrrolidinone (NMP) and acetone to create a polymer solution containing 16 wt% PVDF, with an NMP/acetone volume ratio of 5/5.
· The fibers were generated using a vertical electrospinning setup, incorporating a temperature-controlled collector. Prior to electrospinning, the clear polymer solution was degassed to eliminate bubbles, and the flow rate of the polymer solution was regulated with a precise pump.
· Unless specified otherwise, the voltage applied was 7.5 kV, the flow rate of the polymer solution was 80 lL/h, and the distance between the needle tip and the collector was 10 cm. All tests were conducted in an air atmosphere with a relative humidity ranging from 55 to 60%.

Preparation of Porous PVDF-based Nanocomposite Membranes and Their Application in Lithium-Ion Batteries

Nasrallah, Doaa A., et al. Polymers for Advanced Technologies, 2021, 32(3), 1214-1229.

Polyvinylidene fluoride (PVDF)/lithium titanium oxide Li4Ti5O12 (LTO) nanocomposite films with proportioned LTO nanoparticles (NPs) were successfully prepared by casting method. The results showed that LTO NPs as dopants can effectively enhance the electrical properties of PVDF matrix for high-power lithium-ion batteries and electronic devices.
Preparation procedure of PVDF/Li4Ti5O12 nanocomposite membranes
· To prepare the nanocomposite membranes, the following steps were taken via solution casting.
· Initially, 8 g of Polyvinylidene fluoride (Mw = 534,000 g mol-1) was dissolved in DMSO at 70°C, with stirring for 6 hours until complete dissolution of the polymer.
· Following this, spinel lithium titanate oxide LiTisO12 NPS (Mw = 459.1 g mol-1) were suspended in DMSO through sonication for 30 minutes.
· Subsequently, varying volume fractions (0.25, 0.5, 0.75, and 1.0 vol%) of LTO NPS were introduced to the PVDF solution under stirring at room temperature (RT) for 3 hours, followed by sonication for 30 minutes to achieve homogeneity and prevent NPs aggregation.
· The resulting solutions were then poured into a clean glass Petri dish and oven-dried at 50°C for 3 days to remove excess solvent. Films were removed from the plates and stored in a vacuum desiccator until measurement. Film thickness was determined using a thickness gauge (ASTM D1777) and was approximately 0.3 mm.

Custom Q&A

What is PVDF?

PVDF is a semi-crystalline thermoplastic fluoropolymer.

What are the production methods for PVDF?

PVDF is generally synthesized through free radical polymerization of 1,1-difluoroethylene (CH2=CF2) in the suspension or emulsion.

What are the properties of PVDF?

PVDF has a crystal structure and exists in four possible conformations named α, β, γ, and δ phases. It has high mechanical strength and is non-flammable. It also exhibits good resistance to UV light and chemicals.

What are the electrical properties of PVDF?

PVDF has high dielectric constant and dissipation factor, making it suitable for wire and cable isolation. It can also exhibit piezoelectric and pyroelectric behavior.

How can PVDF be processed?

PVDF can be processed using techniques applicable to standard thermoplastics, such as extrusion, injection molding, compression molding, transfer molding, and machining.

Does PVDF require drying before processing?

Drying of PVDF resin before processing is usually not necessary.

What is the recommended temperature range for processing PVDF?

The processing temperature for PVDF is between 190 to 280°C for various processing methods.

What are the recommended parameters for injection molding PVDF?

The melt temperature for injection molding PVDF should be between 200-270°C, and a mold temperature of 50-95°C is recommended. Proper mold design is important due to the relatively high melt viscosity of PVDF.

What precautions should be taken during extrusion of PVDF?

Attention should be paid to eliminating dead spots where degradation of the polymer can start. The extrusion temperature for PVDF ranges from 230 to 290°C, and no extrusion aids, lubricants, or heat stabilizers are needed.

What is the recommended L/D ratio for extrusion of PVDF?

An L/D ratio of at least 20 is recommended for extrusion of PVDF.

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