Without cryogenic a plastic pulverizer machine, also known as a plastic mill or grinder, is a mechanical device used to grind plastic materials into fine powders or particles of course you can make powder from plastic or change plastic to powder into different particle size by hashing plastic and crushing otherwise the powder metallurgy is process which is used to change the shape of metal from powder to part according to die of forming. The plastic polarizer machine are available in various size depending upon the requirements.

Making plastic powder involves mechanical or chemical processes to reduce the size of plastic particles without the use of liquid nitrogen. Here are some methods to achieve this:

### Mechanical Methods

1. **Cryogenic Grinding (without Liquid Nitrogen)**

- **Alternative Coolants**: Use other coolants like dry ice (solid carbon dioxide) or liquid carbon dioxide (CO₂) to lower the temperature of the plastic before grinding. This can make the plastic brittle and easier to grind.

- **Procedure**:

1. Mix plastic pellets with dry ice in a suitable ratio.

2. Use a high-speed mill or grinder to grind the mixture into a fine powder.

3. Allow the dry ice to sublimate (turn into gas) leaving behind the plastic powder.

2. **Mechanical Milling**

- **Ball Milling**: Use a ball mill where plastic pellets are placed in a rotating cylinder with grinding media (balls). The rotation causes the balls to collide with the plastic, breaking it down into powder.

- **Procedure**:

1. Load the ball mill with plastic pellets and grinding media.

2. Seal the mill and start the rotation.

3. Run the mill for a sufficient period to achieve the desired powder size.

4. Sieve the powder to obtain a uniform particle size distribution.

3. **Jet Milling**

- **Air Jet Mill**: Utilize high-velocity air streams to collide and pulverize plastic particles into fine powder.

- **Procedure**:

1. Feed the plastic granules into the jet mill.

2. The high-speed air jets create a vortex that grinds the plastic into powder.

3. Collect the powder through a cyclone separator.

### Chemical Methods

1. **Solvent Precipitation**

- **Dissolution and Precipitation**: Dissolve the plastic in a suitable solvent and then precipitate it by adding a non-solvent, followed by drying.

- **Procedure**:

1. Dissolve plastic in a compatible solvent (e.g., dissolving polystyrene in acetone).

2. Add a non-solvent (e.g., water for polystyrene) to precipitate the plastic.

3. Filter and wash the precipitated plastic particles.

4. Dry the particles to remove residual solvent and obtain a powder.

2. **Chemical Degradation**

- **Depolymerization**: Use chemical processes to break down the plastic into its monomers or smaller molecules, which can then be re-polymerized or processed into powder.

- **Procedure**:

1. Treat the plastic with chemical reagents that depolymerize it (e.g., hydrolysis for certain polyesters).

2. Isolate the degraded plastic fragments.

3. Grind or mill the fragments into a fine powder.

### Practical Considerations

- **Safety**: Ensure proper handling and safety measures, especially when using chemicals or operating high-speed machinery.

- **Material Properties**: Consider the type of plastic and its thermal and mechanical properties to choose the most suitable method.

- **Particle Size**: Use sieving or other separation techniques to achieve uniform particle sizes.

### References

- Pochiraju, K., & Tandon, R. (2012). "Manufacturing Techniques for Polymer Matrix Composites (PMCs)." Woodhead Publishing.

- Research articles and industrial guidelines on plastic milling and grinding techniques.

By carefully selecting the appropriate method and optimizing the process parameters, you can effectively produce plastic powder without using liquid nitrogen.

Creating plastic powder without liquid nitrogen involves several methods. Mechanical grinding can be done at ambient temperature or with dry ice cooling, using shredders and high-speed mills to reduce plastic into powder. Solution precipitation involves dissolving plastic in a solvent, then precipitating, filtering, and drying it. Spray drying creates fine powders by atomizing a plastic solution and evaporating the solvent in a heated chamber. Mechanical pulverization employs pulverizers to crush shredded plastic into fine particles. Each method is chosen based on the plastic's properties, desired particle size, safety, and environmental impact considerations.