When it comes to packaging materials, PVC and PVDC are two commonly used polymers. Although both materials have similar names and are often used for the same applications, they differ in composition, properties, and applications. In this article, we will explore the differences between PVC and PVDC in detail.
Differences in Composition
PVC, or polyvinyl chloride, is a thermoplastic polymer that is made from vinyl chloride monomer. It is produced by polymerization of vinyl chloride monomer using an initiator such as peroxides. PVC contains 57% chlorine by weight, which gives it its chemical resistance and flame-retardant properties.
On the other hand, PVDC, or polyvinylidene chloride, is a thermoplastic polymer that is made from vinylidene chloride monomer. PVDC is synthesized by free radical polymerization of vinylidene chloride monomers. The polymer contains up to 90% chlorine by weight and is known for its excellent barrier properties against gases, water vapor, and aromas.
Differences in Properties
The properties of PVC and PVDC differ significantly due to their different compositions. PVC is a tough, rigid, and brittle material. It has a density range of 1.3-1.58 g/cm³ and a melting point of around 100°C. PVC is also resistant to chemicals, weathering, and abrasion.
PVDC, on the other hand, is a flexible and transparent material with a high tensile strength and tear resistance. It has a density of around 1.7 g/cm³ and a melting point of around 190°C. PVDC is highly resistant to acids, alkalies, solvents, and oils. It also has excellent thermal stability and can withstand temperatures of up to 120°C.
Differences in Applications
Due to their different properties, PVC and PVDC are used for different applications. PVC is commonly used in construction, as it is a popular material for pipes, window frames, and flooring. It is also used in the packaging industry to make films, bottles, and containers.
PVDC, on the other hand, is mainly used in the food and pharmaceutical industries. Due to its excellent barrier properties, it is used to make blister packs, shrink wraps, and other packaging materials that require a high degree of protection against moisture, gases, and aromas. PVDC is also used to coat paper and films to improve their barrier properties.
In conclusion, PVC and PVDC are two different polymers that differ in composition, properties, and applications. While PVC is a tough and rigid material with good chemical resistance, PVDC is a flexible and transparent material with excellent barrier properties. Understanding the differences between these two materials is important for selecting the right polymer for your specific application.
Conclusion
In summary, PVC and PVDC are two polymers that have unique properties and are suitable for different applications. PVC is a tough and rigid material that is commonly used in construction and packaging, while PVDC is a flexible and transparent material that is used in the food and pharmaceutical industries due to its excellent barrier properties. With the information provided in this article, you should now be able to choose the right polymer for your specific application.
