Understanding Chemical Compatibility: A Comprehensive Labware Selection Guide
Chemical compatibility plays a crucial role in laboratory safety and efficiency. Selecting the wrong materials can lead to equipment degradation, contamination, or hazardous reactions. This guide explores how various chemicals interact with different types of labware plastics.
Factors Affecting Chemical Resistance
Several factors influence the chemical resistance of plastics:
- Chemical Attack on Polymer Chains: Some chemicals degrade polymer structures, weakening strength and flexibility.
- Physical Changes: Chemical absorption can cause swelling, softening, or dissolution of plastic materials.
- Environmental Stress Cracking: Stress and chemical exposure can lead to unexpected material failure.
- Temperature and Pressure: High temperatures reduce chemical resistance, while pressure accelerates degradation.
Overview of Plastic Types and Their Chemical Resistance
Choosing the right plastic for labware depends on its chemical compatibility:
- Fluoropolymers (PTFE, FEP, PFA, TFE, ETFE): Exceptional resistance to acids, bases, and solvents; ideal for aggressive environments.
- Polypropylene (PP) and Polypropylene Copolymer (PPCO): Resistant to acids, bases, and solvents but vulnerable to strong oxidizers.
- Polycarbonate (PC): Moderate resistance; susceptible to stress cracking from alcohols and detergents.
- Polyethylene (LDPE, HDPE, FLPE): Resistant to many chemicals but affected by hydrocarbons and oils.
- Polystyrene (PS) and Acrylic (PMMA): Limited chemical resistance, unsuitable for strong solvents.
Chemical Compatibility Table
The following table summarizes the resistance of plastics to various chemicals. Ratings are classified as:
- E – Excellent: No damage after 30 days of constant exposure.
- G – Good: Little or no damage after 30 days.
- F – Fair: Some effect after 7 days of exposure.
- N – Not Recommended: Immediate damage may occur.
| Chemical | LDPE | HDPE | PP | PPCO | PC | PS | PMMA | FEP | PTFE | PFA |
|---|---|---|---|---|---|---|---|---|---|---|
| Acetone | G | N | F | N | E | N | N | E | E | E |
| Ammonia | E | E | E | E | E | N | N | E | E | E |
| Benzene | N | N | N | N | G | N | N | E | E | E |
| Chloroform | N | N | N | N | F | N | N | E | E | E |
| Ethanol | E | E | E | E | E | N | N | E | E | E |
| Hydrochloric Acid (conc.) | E | E | E | E | E | N | N | E | E | E |
| Nitric Acid (conc.) | N | N | N | N | E | N | N | E | E | E |
| Sulfuric Acid (conc.) | E | E | E | E | E | N | N | E | E | E |
| Toluene | N | N | N | N | G | N | N | E | E | E |
Note: This is a summarized version of the full chemical resistance table.
Key Takeaways
- Choose the Right Material: Fluoropolymers provide the highest resistance, while polycarbonate and polystyrene are prone to chemical attack.
- Test in Real Conditions: Laboratory conditions vary; testing under specific working environments ensures accuracy.
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Avoid Stress Cracking Agents: Detergents, oils, and solvents may cause unexpected material failure.
- Chemical compatibility in laboratories
- Best plastic labware for chemicals
- Chemical resistance of plastics
- Laboratory safety materials
- Choosing the right plastic for labware
