## How to Identify Plastic Scrap: A Professional Guide
Correctly identifying plastic types is essential for quality control. Whether you are dealing with Polypropylene (PP), Polycarbonate (PC), or Polystyrene (PS), these simple, field-tested methods will help you sort your materials accurately.
### 1. The Water Float Test
Plastics have different densities, allowing you to separate them using a simple bucket of tap water.
* **PP (Polypropylene):** A low-density plastic that will **float**.
* **PS & PC:** Both are denser than water and will **sink**.
### 2. The Flex and Snap Test
Once you have isolated the plastics that sink, use this test to distinguish between PC and PS based on their durability.
* **PC (Polycarbonate):** Known for being incredibly tough and impact-resistant. It will warp, fold, or flex under pressure without breaking.
* **PS (Polystyrene):** A rigid but brittle material. If struck or bent forcefully, it will **snap or shatter** rather than flex.
### 3. The Acetone Test (Chemical Identification)
Acetone is a highly effective tool for verifying your material. Apply a few drops to a clean sample and observe the reaction for 30 seconds.
| Plastic Type | Reaction to Acetone |
| — | — |
| **PS (Polystyrene)** | **Dissolves:** Becomes sticky, melts, or liquefies. |
| **PC (Polycarbonate)** | **Clouds:** The surface loses clarity and turns permanently hazy/white. |
| **PP (Polypropylene)** | **No Reaction:** The plastic remains completely unchanged. |
> **Safety First:** Always wear safety glasses and gloves when handling chemicals. Perform these tests in a well-ventilated area or outdoors.
### 4. The Burn Test
If you are still unsure, a flame test provides a definitive answer:
* **PC:** Ignites with difficulty; produces yellow-black smoke; gives off a sweet, floral odor.
* **PP:** Burns easily with a yellow flame; drips like a candle; smells like burning wax or oil.
* **PS:** Burns with a bright, luminous flame; produces thick, black, sooty smoke; gives off a strong floral/gassy scent.
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**Need expert help sorting your scrap?**
To help us provide better guidance, please consider the following:
* **Form:** Is your scrap in shredded flake form or in larger molded parts?
* **Origin:** Do you know the original products the scrap came from (e.g., electronic casings, water bottles, food containers)?
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