Polyethylene (PE) is the most widely used plastic globally, valued for its versatility, cost-effectiveness, and adaptable properties. Its features vary by density (e.g., LDPE, HDPE, LLDPE), but core characteristics include:  

 Core Features:  

1. Chemical Resistance  

   - Highly resistant to acids, bases, solvents, alcohols, and water.  

   - Ideal for containers holding cleaning agents, fuels, and chemicals.  

2. Moisture Barrier  

   - Excellent water vapor barrier (low permeability), making it perfect for packaging films, bottles, and pipes.  

3. Flexibility & Toughness  

   - LDPE/LLDPE: Highly flexible, impact-resistant (e.g., squeeze bottles, plastic bags).  

   - HDPE: Rigid yet tough (e.g., milk jugs, cutting boards).  

4. Electrical Insulation  

   - Low electrical conductivity, widely used in wire/cable coatings.  

5. Lightweight  

   - Low density (0.91–0.97 g/cm³), reducing transport costs.  

6. Ease of Processing  

   - Easily molded via injection molding, blow molding, or extruded into films/fibers.  

7. Food-Safe & Non-Toxic  

   - FDA/EC compliant grades available for food packaging and medical devices.  

8. Recyclability  

   - Widely recycled (♳: HDPE, ♴: LDPE).  

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 Variants & Their Unique Traits:

 Type  Density  Key Properties  Common Uses   

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 HDPE  High (0.94–0.97 g/cm³)  Rigid, strong, weather-resistant  Pipes, fuel tanks, toys, hard hats   

 LDPE  Low (0.91–0.93 g/cm³)  Flexible, transparent, easy to seal  Plastic bags, cling film, squeezable bottles   

 LLDPE  Linear Low  Superior puncture/impact resistance  Stretch wrap, agricultural films, covers   

 UHMWPE  Ultra-High  Extreme abrasion resistance, low friction  Medical implants, conveyor belts, bulletproof vests   

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 Limitations:  

- Low Heat Resistance: Softens at 80–120°C (varies by type).  

- UV Degradation: Requires additives (e.g., carbon black) for outdoor use.  

- Poor Adhesion: Surface treatments needed for printing/gluing.  

- Permeable to Gases: Not ideal for carbonated drinks (often uses PET instead).  

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 Applications:  

- Packaging: Bags, films, bottles, containers.  

- Construction: Pipes, geomembranes, insulation.  

- Consumer Goods: Toys, kitchenware, caps.  

- Industrial: Chemical tanks, cutting boards, bearings.  

PE’s balance of durability, processability, and recyclability ensures its dominance across industries, though selecting the