Milky plastic most likely refers to casein plastic, a type of early plastic made from milk protein (casein).
Here's a more detailed explanation:
-
Casein Plastic (Milk Plastic): This is a bioplastic made from casein, the protein found in milk. It was one of the earliest forms of plastic, developed in the late 19th century.
- How it's made: Casein plastic is typically made by extracting casein from milk and then treating it with chemicals like formaldehyde. The process involves separating the casein from the whey, pressing it, and then hardening it. While the referenced short answer mentions using vinegar or lemon juice, those would typically be used in a more simplified, at-home version to precipitate the casein. The larger scale industrial method would differ.
- Renewable Resource: Because milk is a renewable resource, casein plastic can be considered a more sustainable option compared to plastics derived from petroleum.
- Properties: Casein plastic is hard, durable, and can be molded into various shapes. It can also be dyed in various colors. However, it's not as water-resistant or flexible as some modern plastics.
- Uses: Historically, casein plastic was used to make buttons, beads, combs, pen caps, knitting needles, and other decorative items. Its use has declined with the advent of cheaper and more versatile petroleum-based plastics, but there's renewed interest in it as a sustainable alternative.
- Modern applications: With growing environmental awareness, casein plastic is seeing a resurgence in research and development for niche applications, often touted as an eco-friendly option.
