Bioplastics - definition, production & applications

What makes a plastic a bioplastic?

• based on renewable raw materials (matières 1res)

AND/OR

• biodegradable plastics

What’s the definition of biodegradable?

Materials that can be broken down naturally by microorganisms into natural simpler substances

Among all the plastics types, which ones are bioplastics?

Even plastics based on 100% of raw oil but biodegradable are considered as bioplastics

Why using bioplastics?

to shorten the carbon cycle → prevent animals to eat them…

Explain both carbon cycles of bioplastics and conventional plastics

How long does bioplastics’ carbon cycle last compared to conventional plastics?

• bioplastics → ~ 10 years

• fossil plastics → ~ 1 million years

What are the 3 different sources of bioplastics’ raw materials?

Which ones are the most common?

(Where do the monomers can come from)

What are the 3 different ways of producing bioplastics?

Note: each process doesn’t correspond to one source of raw materials, they can be applied to various raw materials, regardless their origin

Why do some companies use bioplastics although it’s expensive?

• good image

• Forced by the law (regulations about carbon footprint)

List all the bioplastics you know

• CA cellulose acetate

• PBAT polybutylene advocate terephthalate

• PBS polybutylene succitane

• PHA polyhydroxyalkanoates

• PLA polyactide / polylactic acid

• TPS thermoplastic starch

Properties & applications of polylactide / polylactic acid PLA

+ polymerised from lactic acid (derived from corn, rice, potatoes, tapioca)

+ excellent chemical resistance Low water

+ easy to process

- very brittle at low temperature (low temperature resistance)

• injection moulding (moulage par injection)

• Blown & flat films (food packaging, biodegradable bags)

• Fibres (textiles)

• Coating (inner layer of paper cups)

Properties & applications of thermoplastic starch TPS

+ chemically and thermally modified (enhanced properties)

+ fast & good biodegradability (water soluble)

+ very elastic

- poor hydrolysis resistance (degrades when exposed to moisture = humidité)

• blown & flat films

• Foam trays (plateau en “mousse” des paquets de fruits)

• Coatings (add barrier properties

Properties & applications of cellulose acetate CA

+ basic properties similar to polystyrene PS

+ very glossy/shiny & only slightly opaque

+ excellent chemical resistance Low water

- can only be melted and processed if modified (external plasticisers)

- expensive

• injection moulding

• Films

• Packaging

• Cosmetic articles

• Foam

Properties & applications of polyhydroxyalkanoates PHA

+ polyester produced from sugar or starch by fermentation

+ good sealing properties (étanchéité)

+ excellent biodegradability

+ highly flexible (PHV) to very rigid (PHB)

- after crystallisation → very brittle

• injection moulding

• Blown films

• Horticulture

• Catering (restauration)

Properties & applications of polybutylene succinate PBS

+ up to 40% bio based

+ similar to PBT (good insulation capacity)

+ flexible

+ very stable

+ biodegradable

• Injection moulting copolymer

• Blown & flat films (Packaging, sealing layers, mulch films = in agriculture, laid on the soil)

Properties & applications of polybutylene adipate terephthalate PBAT

+ soft material, similar to LD-PE

+ excellent compatibility with PLA (stick together very well)

- fossil based but biodegradable

• shrink & packaging films

• Blown films

• Paper costing (barrier properties → bags, compost bags, mulch films)

What’s the problem with some plastic films used for food packaging?

Some of these films are made with multiple layers of different plastics (up to 6…), each having a specific purpose.

However, as they’re stuck (collés) together, we can’t separate them and thus, they’re not recyclable (unless the energy from burning them is used for something)