TPS
Thermoplastic Starch
Glass Transition (Tg)
plasticizer-dependent
Melting Point (Tm)
— (degrades)
Density
1.40–1.50 g/cm³
CAS Number
9005-25-8
Recycling Code
♺ 7
Category
Biodegradable
Repeat Unit
–[C₆H₁₀O₅]ₙ– (α-1,4 & α-1,6)
The repeating unit is the smallest structural fragment whose repetition builds the whole chain. Subscripts show the relative share of each unit in copolymers.
Key Properties
Natural starch plasticised with glycerol/water to become melt-processable; cheapest bioplastic but strongly hygroscopic with poor wet strength; properties drift over time (retrogradation).
Applications
Loose-fill packaging, compostable bag blends, foam trays.