Basics Of Biopolymers: Materials, Properties, And Injection Moulding Applications
Biopolymers are gaining prominence in modern manufacturing as industries shift towards sustainable and eco-friendly materials. As the world continues to face challenges associated with plastic waste, carbon emissions, and resource depletion, biopolymers have emerged as a viable alternative to traditional plastics made from petroleum. Currently, biopolymers are applied in the packaging industry, consumer products, healthcare, and agriculture, and are compatible with traditional manufacturing processes such as injection moulding.
Knowledge of biopolymer basics enables manufacturers to choose the appropriate materials and manufacturing processes.
Biopolymers are polymer materials that are made from natural resources like corn starch, sugarcane, cellulose, and microbial fermentation. Unlike traditional plastics, biopolymers are either bio-based polymers, biodegradable plastics, or compostable plastics. This makes biopolymers less dependent on fossil fuels and have a lower environmental impact compared to traditional plastics.
Some of the most common types of biopolymer materials include PLA biopolymer (Polylactic Acid), PHA biopolymer (Polyhydroxyalkanoates), starch-based biopolymers, and cellulose-based polymers. These materials have different properties, making biopolymers versatile in plastic manufacturing.
Biopolymers can be classified in several ways depending on their source and behaviour.
Based on Origin
• Natural Biopolymers: Found in nature
Examples: cellulose, starch, natural rubber
• Bio-based Synthetic Polymers: Produced using renewable raw materials
Examples: PLA (Polylactic Acid), PHA (Polyhydroxyalkanoates)
Based on Degradability
• Biodegradable Biopolymers: Break down under specific environmental conditions
• Non-biodegradable Bio-based Polymers: Renewable but designed for long-term use
Each type serves different industrial needs, from disposable packaging to durable molded components.
The properties of biopolymers vary depending on their composition, but several key characteristics define their industrial use. Many biopolymers offer good surface finish, dimensional stability, and processability, making them compatible with injection moulding machines. However, compared to conventional plastics, biopolymers often have lower heat resistance and narrower processing windows.
Moisture sensitivity is another important factor. Proper material drying, accurate temperature control, and stable injection parameters are essential to prevent degradation and ensure consistent part quality. Understanding the mechanical and thermal properties of biopolymers is critical for successful large-scale production.
Injection moulding is widely used for high-volume plastic part production. Biopolymers can be processed on conventional injection moulding machines when key parameters are carefully controlled.
Successful biopolymer moulding depends on:
• Stable barrel temperature profiles
• Controlled screw speed
• Consistent injection pressure
With correct processing, biopolymers can produce complex shapes, thin-wall parts, and uniform surface finishes.
Biopolymers are increasingly used in everyday and industrial products, including:
• Packaging: food containers, caps, closures, disposable items
• Consumer goods: household and lifestyle products
• Healthcare: single-use components requiring sustainability
These applications show how biopolymers are becoming mainstream materials in injection moulding.
Biopolymers require precise process control due to their sensitivity to heat and moisture. Injection moulding machines with stable clamping, accurate temperature regulation, and consistent injection performance are essential for reliable biopolymer processing.
At STM Plastics, machines are designed to process bio-based polymers and conventional plastics with equal stability. This flexibility helps manufacturers adopt sustainable materials while maintaining quality, efficiency, and production consistency.
