What are Bioplastics?
Bioplastics are not a single kind of polymer but rather a family of materials that can vary considerably from one another. There are three groups in the bioplastics family, each with its own individual characteristics:
- Bio-based or partially bio-based, non-biodegradable plastics such as bio-based PE, PP, or PET (so-called drop-ins) and bio-based technical performance polymers such as PTT (Poly Trimethylene Terephthalate) or TPC-ET (Thermoplastic Polyester Elastomer).
- Plastics that are both bio-based and biodegradable, such as PLA (Poly Lactic Acid) and PHA (Poly Hydroxyalkanoates) or PBS (Poly Butylene Succinate).
- Plastics that are based on fossil resources and are biodegradable, such as PBAT (Polybutyrate Adipate Terephthalate).
What is biodegradation?
Are biodegradable plastics a solution for the littering problem?
A product should always be designed with an efficient and appropriate recovery solution in mind. In the case of biodegradable plastic products, the preferable recovery solution is the separate collection together with the biowaste, organic recycling (e.g. composting in industrial composting plant or anaerobic digestion in AD plants), and hence the production of valuable compost or biogas. SA Bioplastics Forum does not support any statements that advertise bioplastics as a solution to the littering problems. Littering refers to careless discarding of waste and is not a legitimate means of disposal.
Biodegradable plastics are often regarded as a possible solution to this problem as they can be decomposed by microorganisms without producing harmful or noxious residue during decomposition. However, the process of biodegradation is dependent on certain environmental conditions (i.e. temperature, presence of microorganisms, timeframe, etc.). Products suitable for industrial composting (as defined according to the European standard for industrial compostability EN 13432) are fit for the conditions in a composting plant, but not necessary for those outside in nature.
Littering should never be promoted for any kind of material or waste. It is imperative for the consumer to continue to be conscious of the fact that no matter what type of packaging or waste, it must be subject to appropriate disposal and recovery processes.
Can bioplastics be mechanically recycled?
If a separate recycling stream for a certain plastic type exists, the bioplastic material can simply be recycled together with their conventional counterpart – e.g. bio-based PE in the PE-stream or bio-based PET in the PET stream – as they are chemically and physically identical in their properties.
The post consumer recycling of bioplastics materials for which no separate stream yet exists, will be feasible, as soon as the commercial volumes and sales increase sufficiently to cover the investments required to install separate recycling streams. It is expected, that new separate recycling streams for PLA for example will be feasible and introduced in the short to medium term
Are the properties of bioplastics equal to those of convention plastics?
Today, there is a bioplastic alternative for almost every conventional plastic material and corresponding application. Bioplastics – plastics that are biobased, biodegradable, or both – can have the same properties as conventional plastics and offer additional advantages, such as a reduced carbon footprint or additional waste management options such as industrial composting.
Some bioplastics offer additional functionalities, such as biodegradability or compostability, and improved properties, such as increased heat resistance, enhanced moisture or gas barriers, greater stiffness and flexibility or improved durability.
Bioplastics are available in a wide variety of types and compounds that can mostly be converted on the standard equipment generally used for processing conventional plastics
What are the advantages of bioplastic products?
Bio-based plastics can help to reduce the dependency on limited fossil resources, which are expected to become significantly more expensive in the coming decades. Bio-based plastics are made from renewable sources instead of oil and that way gradually substitute fossil resources used to produce plastics with renewable resources (currently predominantly annual crops, such as corn and sugar beet, or perennial cultures, such as cassava and sugar cane).
Bio-based plastics also have the unique potential to reduce GHG emissions or even be carbon neutral. Plants absorb atmospheric carbon dioxide as they grow. Using plants (i.e. biomass) to produce bio-based plastics constitutes a temporary removal of greenhouse gases (CO2) from the atmosphere. This carbon fixation can be extended for a period of time by establishing ‘use cascades’, that means if the material is being reused or recycled as often as possible before being used for energy recovery. In energy recovery, the previously sequestered CO2 is released and renewable energy is being produced.
Another major benefit of bio-based plastics is their potential to ‘close the cycle’ and increase resource efficiency. Depending on the end-of-life option, this can mean:
- Renewable resources are used to produce bio-based, durable products that can be reused, mechanically recycled and eventually incinerated whereby renewable energy is being produced.
- Renewable resources are used to produce bio-based, biodegradable and compostable products that can be organically recycled (industrial composting and anaerobic digestion) at the end of a product’s life cycle (if certified accordingly) and create valuable biomass (humus) during the process. The humus can be used to grow new plants, thus closing the cycle.
Furthermore, plastics that are bio-based and compostable can help to divert biowaste from landfill and increase waste management efficiency across South Africa.
Are bioplastics more expensive than conventional plastics?
The cost of research and development still makes up for a share of investment in bioplastics and has an impact on material and product prices. Additionally, the currently low oil prices are making it difficult for bioplastics to achieve competitive pricing levels compared to conventional plastics at present. However, prices have continuously been decreasing over the past decade. As more companies and brands are switching to bio-based plastics, and as production capacities are rising, supply chains and processes are becoming more efficient, and prices have come down significantly. With rising demand and more efficient production processes, increasing volumes of bioplastics on the market and oil prices expected to rise again, the costs for bioplastics will soon be comparable with those for conventional plastic prices.
Moreover, specific material properties of bioplastic materials can allow for a reduction of the overall volumes of materials needed for a product or application as well as for cost reduction in the use or end-of-life phase. Already today, there are several examples of cost competitive bioplastic materials and products.