PPS popular modification application direction

In recent years, with the popularity of 5G and electric vehicles, the application of modified PPS is constantly expanding, such as battery brackets, cover plates, lithium battery diaphragms, 5G communication equipment, intelligent terminals, and so on.PPS UD Tape

Let's take a look at the popular modification directions of PPS currently applied in these industries.

Reinforcement and toughening

PPS is currently mainly through fiber filling and alloy two ways to improve the mechanical properties.

In addition to the common glass fiber reinforcement, the current fillers such as carbon fiber and aramid fiber are also gradually "popular" modification systems

In addition to fiber, alloy blending is another effective modification system. One of them has to focus on the PPS/ elastomer system.

In popular terms, the modification principle of elastomer is equivalent to a layer of "airbag" on the material: when the blend is impacted, the elastomer particles will first deform and absorb the impact energy through microholes and holes; At the same time, shear yield or silver grain is produced, so that the material is changed from brittle fracture to ductile fracture, and the toughness is improved.

Low dielectric modification

The lower the dielectric, the less the loss, and the more so under 5G high frequency in order to improve the dielectric properties of materials, the way of blending alloys is generally used. For example, PPS/LCP, according to research, the alloy system can be at 1MHz, the optimal dielectric constant up to 2.5.

In addition to alloys, low dielectric fillers are also one of the possible methods. Fillers such as hollow glass beads and low dielectric glass fiber can also effectively reduce the dielectric constant of PPS composites.

According to research, after extrusion molding, the dielectric constant can be reduced to less than 3, and the electrical performance is stable within 40-120℃. In addition, the strength and dielectric properties of the composites can be further improved by surface coupling treatment of the fillers.

Thermal conductivity modification

In application scenarios such as new energy vehicle power batteries or 5G high frequency, not only do materials require good heat resistance, but also put forward certain requirements for heat conduction. However, the thermal conductivity of PPS itself is poor, generally lower than 0.5W/(m·K).

At present, the main use of metal and inorganic filler two ways. Although the metal filler can improve the thermal conductivity, it will also reduce the insulation performance.

Inorganic fillers, including oxides, nitrides, carbon materials, etc. PPS/ magnesium oxide is the mainstream choice, which can increase the thermal conductivity of the material to 1.61W/(m·K);

The nitride is more complex in preparation and technology, but the thermal conductivity is also higher: the thermal conductivity of 40% boron nitride composite can reach 4.15 W/(m·K);

Carbon materials such as graphene and CNT are also the choice of PPS thermal conductivity modification, and a better balance can be achieved between the addition amount and thermal conductivity, such as graphene with a volume fraction of 29.3% can make the thermal conductivity of the composite reach 4.414W/(m·K).

Composite membrane modification

For the lithium battery diaphragm market, PPS is also being applied.

Previously, the commonly used diaphragm material is polyolefin, but the electrolyte infiltration and thermal stability of polyolefin materials is relatively poor, and it is easy to shrink and melt at high temperatures.

The chemical resistance and heat resistance of PPS material also have certain potential for modification. At present, the main method is to coat the surface of PPS diaphragm to prepare composite diaphragm.

This method has gradually moved from academic research to industrial application: PPS non-woven fabric is used as the substrate, PVS is used as the coating material, and PVS/PPS non-woven lithium battery composite diaphragm is prepared through physical coating, drying and hot pressing treatment.

Compared with traditional polyolefin membranes, PVS/PPS can guarantee better infiltrating properties and higher discharge specific capacity than polyolefin membranes, although the thickness is increased.

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