The difference between PC and PET as track etching film materials

PC (polycarbonate) and PET (polyethylene terephthalate) are the two most commonly used materials for track etching films. They both have good etching track properties, but there are also some qualitative differences in material properties. difference.

In terms of polymer structure, PC is a thermoplastic polymer formed by the polymerization reaction of two compounds, bisphenol A and phosgene, to form strong carbonate bonds; PET is a thermoplastic polyester formed by the condensation polymerization of ethylene glycol and terephthalic acid. Composed of repeating ester units in the polymer chain.

In terms of chemical composition, the molecular structure of PC contains aromatic rings and carbonate groups. The presence of aromatic rings contributes to its rigidity and thermal stability; the molecular structure of PET contains aromatic rings and ester groups. The ester groups make PET useful in certain applications. It is easily hydrolyzed under conditions such as high temperature, strong acid or alkali, and long-term exposure to moisture.

In terms of mechanical properties, PC has excellent mechanical properties, including high tensile strength, impact resistance and dimensional stability, and is a hard and tough material; PET also has good mechanical properties, including high tensile strength and stiffness. Relatively more flexible than PC , thanks to even relatively weak intermolecular forces allowing more movement and flexibility between polymer chains.

In terms of thermal properties, the glass transition temperature (Tg) is commonly used to compare the thermal properties of this type of material. It refers to the temperature at which the polymer changes from a rigid glassy state to a softer rubbery state. PC has a higher glass transition temperature (Tg). ), usually about 140-150°C, has good heat resistance and can withstand high temperatures without significant deformation; the glass transition temperature of PET is lower than PC (Tg), usually about 70- 80°C, has good thermal stability within this temperature range, but may soften or deform beyond this temperature range. Compared with PC, although PET has a lower Tg, it can achieve flexibility at lower temperatures, especially at room temperature. It is more flexible than PC.

In terms of chemical resistance, PC has good resistance to many chemicals, including acids, alkalis and alcohols, which is equivalent to solvent resistance and can withstand contact with a variety of chemicals; PET has good chemical resistance to weak acids and weak bases, but it will be degraded or hydrolyzed by strong acid or alkali, and is sensitive to some organic solvents.

In terms of track etching characteristics and process, PC is usually used in track etching applications due to its excellent track forming ability. Its rigid and stable structure can achieve precise and well-defined track etching; compared with PC, PET requires more professional Environmental conditions are required to achieve orbit formation.

The above summary is the major difference between the two materials, but these differences are not the only factors that determine material selection, because the specific characteristics and performance of the material may vary due to factors such as molecular weight, processing conditions, and the addition of additives or modifications to the material. Therefore, the specific requirements of the track etching application, cost and other environmental factors must be considered when selecting the appropriate material.