There are several key reasons why polypropylene (PP) is the dominant material choice for microcentrifuge tubes:

• Strength and Durability: Polypropylene is a robust plastic that can withstand the high speeds and forces encountered during centrifugation. This ensures the tubes maintain their shape and integrity without breaking or cracking, which is crucial for sample safety and containment.
• Chemical Resistance:Polypropylene exhibits excellent resistance to a wide range of chemicals commonly used in biological labs. This includes acids, bases, alcohols, and many organic solvents. This chemical resistance prevents the tubes from reacting with or degrading due to the samples they contain.
• Lightweight: Polypropylene is a relatively lightweight plastic compared to some alternatives like glass. This makes microcentrifuge tubes easier to handle and manipulate, especially when working with large numbers of samples in a centrifuge rotor.
• Cost-Effectiveness: Polypropylene is a readily available and inexpensive material compared to other options. This translates to affordable microcentrifuge tubes, making them a cost-effective choice for labs with various budgetary constraints.
• Transparency: Many polypropylene formulations offer good transparency, allowing for visual inspection of the sample contents within the tube.  This is helpful for tasks like checking for cell pellets or solution clarity.
• Sterilizability:Polypropylene tubes can be sterilized using various methods like autoclaving (high-pressure steam sterilization). This allows for working with sterile samples and minimizes contamination risks in experiments.
• Temperature Tolerance: Standard polypropylene tubes can withstand temperatures up to around 120°C (248°F), which is sufficient for most centrifugation applications and sample storage needs in a lab setting.

While other materials like polyethylene (PE) offer some similar properties, polypropylene generally provides a better balance of strength, chemical resistance, and cost-effectiveness, making it the preferred choice for most microcentrifuge tube applications. It's important to note that there can be some variations in polypropylene formulations used for microcentrifuge tubes. And then you might want to figure out what are some common mistakes people make when using microcentrifuge tubes, and how can they be avoided.