What are the crystallinity and molecular orientation characteristics of PVC industrial grey sheet?

The crystallinity and molecular orientation characteristics of PVC industrial grey sheet are key factors that influence its mechanical, thermal, and processing properties:

Crystallinity:
Nature of PVC: PVC (Polyvinyl chloride) is a semi-crystalline polymer, meaning it consists of both crystalline regions (ordered molecular structure) and amorphous regions (disordered molecular structure).
Crystalline Content: The crystallinity of PVC industrial grey sheet refers to the proportion of PVC molecules that are arranged in a crystalline structure. Higher crystallinity generally leads to improved mechanical properties such as stiffness and strength.
Impact on Properties: Higher crystallinity can also affect thermal properties, such as melting point and heat resistance. It may influence chemical resistance and dimensional stability under varying environmental conditions.

Molecular Orientation:
Alignment of Polymer Chains: During the manufacturing process, especially during extrusion or calendering, PVC molecules can align in a preferential direction (molecular orientation).
Effects on Mechanical Properties: Molecular orientation affects mechanical properties such as tensile strength, impact resistance, and dimensional stability. Oriented molecules tend to enhance strength in the direction of alignment but may reduce properties perpendicular to the orientation.
Processing Influence: The processing conditions, including extrusion speed, temperature gradients, and cooling rates, significantly influence the degree and direction of molecular orientation in PVC industrial grey sheet.

Understanding these crystallinity and molecular orientation characteristics is crucial for optimizing the performance of PVC industrial grey sheet in specific applications. Manufacturers may adjust processing parameters to control these properties and achieve desired mechanical, thermal, and dimensional characteristics suited to industrial requirements.