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What is the reason why PTFE plastic is difficult to bond?

Update:20-04-2020
Summary:

In order to make clear the reason why Teflon is difficu […]

In order to make clear the reason why Teflon is difficult to stick, we analyze Teflon from the molecular structure.
PTFE viscosity parameters:
1. The energy required for PTFE to repel the liquid in contact with it is small.
The work W required by the solid to repel the liquid in contact with it (same as the subsequent energy shown in the table).
Polytetrafluoroethylene PTFE has a small adhesive energy, and it can be understood that PTFE easily repels liquid in contact with it. PTFE is more difficult to swell and dissolve than non-crystalline polymers. It is difficult to spread and entangle the polymer molecular chains when the adhesive is coated on the surface of PTFE. It cannot form strong adhesion, and the adhesive liquid is not. Easy to stick to it.

2. The adhesive cannot wet the PTFE surface
Generally, the adhesive is fluid before it is fixed. The bonding process is the distribution of the glue on the bonding surface. The curing process. For the bonding, wet contact is the bonding condition. The wettability of a liquid in contact with a solid can be expressed by the contact angle.

High temperature resistant PTFE film tape

Polytetrafluoroethylene (PTFE) has a symmetrical structure and belongs to a non-molecular polymer. Adsorption of the adhesive on the surface of PTFE is caused by the intermolecular force, which includes orientation force, induced force and dispersion force. PTFE is non-sexual The surface does not have the conditions to form the orientation force and the induction force, and can only form a weak dispersion force, so its adhesion performance is poor.

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