INTRODUCTION
Bioplastics or organic plastics are a form of plastics derived from renewable biomass sources, such as vegetable oil, corn starch, pea starch.
PLASTIC TYPES
STARCH BASED PLASTICS
Constituting about 50 percent of the bioplastics market, thermoplastic starch, such as Plastarch Material, currently represents the most important and widely used bioplastic. Pure starch possesses the characteristic of being able to absorb humidity, and is thus being used for the production of drug capsules in the pharmaceutical sector. Flexibiliser and plasticiser such as sorbitol and glycerine are added so the starch can also be processed thermo-plastically. By varying the amounts of these additives, the characteristic of the material can be tailored to specific needs (also called "thermo-plastical starch").
CELLULOSE BASED PLASTICS
Cellulose bioplastics are mainly the and their derivatives .
SOME ALIPHATIC POLYESTERS
The aliphatic biopolyesters are mainly polyhydroxyalkanoates (PHAs) like the poly-3-hydroxybutyrate (PHB), polyhydroxyvalerate (PHV) and polyhydroxyhexanoate PHH.
POLYLACTIC ACID (PLA) PLASTICS
Polylactic acid (PLA) is a transparent plastic produced from cane sugar or glucose. It not only resembles conventional petrochemical mass plastics (like PE or PP) in its characteristics, but it can also be processed easily on standard equipment that already exists for the production of conventional plastics. PLA and PLA blends generally come in the form of granulates with various properties, and are used in the plastic processing industry for the production of foil, moulds, tins, cups, bottles and other packaging.
POLY-3-HYDROXYBUTYRATE (PHB)
The biopolymer poly-3-hydroxybutyrate (PHB) is a polyester produced by certain bacteria processing glucose or starch. Its characteristics are similar to those of the petroplastic polypropylene.
POLYAMIDE 11 (PA 11)
PA 11 is a biopolymer derived from natural oil. It is also known under the tradename Rilsan B, commercialized by Arkema. PA 11 belongs to the technical polymers family and is not biodegradable. Its properties are similar to those of PA 12, although emissions of greenhouse gases and consumption of nonrenewable resources are reduced during its production. Its thermal resistance is also superior to that of PA 12. It is used in high-performance applications like automotive fuel lines, pneumatic airbrake tubing, electrical cable antitermite sheathing, flexible oil and gas pipes, control fluid umbilicals, sports shoes, electronic device components, and catheters.
BIO-DERIVED POLYETHYLENE
The monomer of polyethylene is ethylene. This is just one small chemical step from ethanol, which can be produced by fermentation of agricultural feedstocks such as sugar cane or corn. Bio-derived polyethylene is chemically and physically identical to traditional polyethylene - it does not biodegrade but can be recycled. It can also considerably reduce greenhouse gas emissions.
GENETICALLY MODIFIED BIOPLASTICS
Genetic modification (GM) is also a challenge for the bioplastics industry. None of the currently available bioplastics - which can be considered first generation products - require the use of GM crops, although gm corn is the standard feedstock.
Looking further ahead, some of the second generation bioplastics manufacturing technologies under development employ the "plant factory" model, using genetically modified crops or genetically modified bacteria to optimise efficiency.
ENVIRONMENTAL IMPACT
The production and use of bioplastics is generally regarded as a more sustainable activity when compared with plastic production from petroleum (petro plastic), because it relies less on fossil fuel as a carbon source and also introduces fewer, net-new greenhouse emissions if it biodegrades.
They significantly reduce hazardous waste caused by oil-derived plastics, which remain solid for hundreds of years, and open a new era in packing technology and industry.
However, manufacturing of bioplastic materials is often still reliant upon petroleum as an energy and materials source. This comes in the form of energy required to power farm machinery and irrigate growing crops, to produce fertilisers and pesticides, to transport crops and crop products to processing plants, to process raw materials, and ultimately to produce the bioplastic, although renewable energy can be used to obtain petroleum independence.
BIOPLASTICS AND BIODEGRADATION
The terminology used in the bioplastics sector is sometimes misleading. Most in the industry use the term bioplastic to mean a plastic produced from a biological source. One of the oldest plastics, cellulose film, is made from wood cellulose.
All (bio- and petroleum-based) plastics are technically biodegradable, meaning they can be degraded by microbes under suitable conditions. However many degrade at such slow rates as to be considered non-biodegradable.Some petrochemical-based plastics are considered biodegradable, and may be used as an additive to improve the performance of many commercial bioplastics.
RECYCLING
There are also concerns that bioplastics will damage existing recycling projects. Packaging such as HDPE milk bottles and PET water and soft drinks bottles is easily identified and hence setting up a recycling infrastructure has been quite successful in many parts of the world. However, plastics like PET do not mix with PLA, yielding unusable recycled PET if consumers fail to distinguish the two in their sorting. The problem could be overcome by ensuring distinctive bottle types or by investing in suitable sorting technology.
COST
With the exception of cellulose, most bioplastic technology is relatively new and is currently not cost competitive with petro plastics. Bioplastics do not yet reach the fossil fuel parity on fossil fuel-derived energy for their manufacturing, reducing the cost advantage over petroleum-based plastic.
However, in certain, special applications bioplastics are already unbeatable because pure material costs form only a part of the entire product costs. For example, medical implants made of PLA, which dissolve in the body, save patients a second operation. Compostable mulch films for agriculture, already often produced from starch polymers, do not have to be collected after use and can be left on the fields.
RESEARCH AND DEVELOPMENT
APPLICATIONS
PERFORMANCE AND USAGE
Bioplastics or organic plastics are a form of plastics derived from renewable biomass sources, such as vegetable oil, corn starch, pea starch.
PLASTIC TYPES
STARCH BASED PLASTICS
Constituting about 50 percent of the bioplastics market, thermoplastic starch, such as Plastarch Material, currently represents the most important and widely used bioplastic. Pure starch possesses the characteristic of being able to absorb humidity, and is thus being used for the production of drug capsules in the pharmaceutical sector. Flexibiliser and plasticiser such as sorbitol and glycerine are added so the starch can also be processed thermo-plastically. By varying the amounts of these additives, the characteristic of the material can be tailored to specific needs (also called "thermo-plastical starch").
CELLULOSE BASED PLASTICS
Cellulose bioplastics are mainly the and their derivatives .
SOME ALIPHATIC POLYESTERS
The aliphatic biopolyesters are mainly polyhydroxyalkanoates (PHAs) like the poly-3-hydroxybutyrate (PHB), polyhydroxyvalerate (PHV) and polyhydroxyhexanoate PHH.
POLYLACTIC ACID (PLA) PLASTICS
Polylactic acid (PLA) is a transparent plastic produced from cane sugar or glucose. It not only resembles conventional petrochemical mass plastics (like PE or PP) in its characteristics, but it can also be processed easily on standard equipment that already exists for the production of conventional plastics. PLA and PLA blends generally come in the form of granulates with various properties, and are used in the plastic processing industry for the production of foil, moulds, tins, cups, bottles and other packaging.
POLY-3-HYDROXYBUTYRATE (PHB)
The biopolymer poly-3-hydroxybutyrate (PHB) is a polyester produced by certain bacteria processing glucose or starch. Its characteristics are similar to those of the petroplastic polypropylene.
POLYAMIDE 11 (PA 11)
PA 11 is a biopolymer derived from natural oil. It is also known under the tradename Rilsan B, commercialized by Arkema. PA 11 belongs to the technical polymers family and is not biodegradable. Its properties are similar to those of PA 12, although emissions of greenhouse gases and consumption of nonrenewable resources are reduced during its production. Its thermal resistance is also superior to that of PA 12. It is used in high-performance applications like automotive fuel lines, pneumatic airbrake tubing, electrical cable antitermite sheathing, flexible oil and gas pipes, control fluid umbilicals, sports shoes, electronic device components, and catheters.
BIO-DERIVED POLYETHYLENE
The monomer of polyethylene is ethylene. This is just one small chemical step from ethanol, which can be produced by fermentation of agricultural feedstocks such as sugar cane or corn. Bio-derived polyethylene is chemically and physically identical to traditional polyethylene - it does not biodegrade but can be recycled. It can also considerably reduce greenhouse gas emissions.
GENETICALLY MODIFIED BIOPLASTICS
Genetic modification (GM) is also a challenge for the bioplastics industry. None of the currently available bioplastics - which can be considered first generation products - require the use of GM crops, although gm corn is the standard feedstock.
Looking further ahead, some of the second generation bioplastics manufacturing technologies under development employ the "plant factory" model, using genetically modified crops or genetically modified bacteria to optimise efficiency.
ENVIRONMENTAL IMPACT
The production and use of bioplastics is generally regarded as a more sustainable activity when compared with plastic production from petroleum (petro plastic), because it relies less on fossil fuel as a carbon source and also introduces fewer, net-new greenhouse emissions if it biodegrades.
They significantly reduce hazardous waste caused by oil-derived plastics, which remain solid for hundreds of years, and open a new era in packing technology and industry.
However, manufacturing of bioplastic materials is often still reliant upon petroleum as an energy and materials source. This comes in the form of energy required to power farm machinery and irrigate growing crops, to produce fertilisers and pesticides, to transport crops and crop products to processing plants, to process raw materials, and ultimately to produce the bioplastic, although renewable energy can be used to obtain petroleum independence.
BIOPLASTICS AND BIODEGRADATION
The terminology used in the bioplastics sector is sometimes misleading. Most in the industry use the term bioplastic to mean a plastic produced from a biological source. One of the oldest plastics, cellulose film, is made from wood cellulose.
All (bio- and petroleum-based) plastics are technically biodegradable, meaning they can be degraded by microbes under suitable conditions. However many degrade at such slow rates as to be considered non-biodegradable.Some petrochemical-based plastics are considered biodegradable, and may be used as an additive to improve the performance of many commercial bioplastics.
RECYCLING
There are also concerns that bioplastics will damage existing recycling projects. Packaging such as HDPE milk bottles and PET water and soft drinks bottles is easily identified and hence setting up a recycling infrastructure has been quite successful in many parts of the world. However, plastics like PET do not mix with PLA, yielding unusable recycled PET if consumers fail to distinguish the two in their sorting. The problem could be overcome by ensuring distinctive bottle types or by investing in suitable sorting technology.
COST
With the exception of cellulose, most bioplastic technology is relatively new and is currently not cost competitive with petro plastics. Bioplastics do not yet reach the fossil fuel parity on fossil fuel-derived energy for their manufacturing, reducing the cost advantage over petroleum-based plastic.
However, in certain, special applications bioplastics are already unbeatable because pure material costs form only a part of the entire product costs. For example, medical implants made of PLA, which dissolve in the body, save patients a second operation. Compostable mulch films for agriculture, already often produced from starch polymers, do not have to be collected after use and can be left on the fields.
RESEARCH AND DEVELOPMENT
- In the early 1950s, Amylomaize (>50% amylose content corn) was successfully bred and commercial bioplastics applications started to be explored.
- In 2004, NEC developed a flame retardant plastic, polylactic acid, without using toxic chemicals such as halogens and phosphorus compounds.
- In 2005, Fujitsu became one of the first technology companies to make personal computer cases from bioplastics, which are featured in their FMV-BIBLO NB80K line.
- In 2007 Braskem of Brazil announced it had developed a route to manufacture high density polyethylene (HDPE) using ethylene derived from sugar cane.
- In 2008, a University of Warwick team created a soap-free emulsion polymerization process which makes colloid particles of polymer dispersed in water, and in a one step process adds nanometre sized silica-based particles to the mix. The newly developed technology might be most applicable to multi-layered biodegradable packaging, which could gain more robustness and water barrier characteristics through the addition of a nano-particle coating .
APPLICATIONS
- Biodegradable bioplastics are used for disposable items, such as packaging and catering items.
- Biodegradable bioplastics are also often used for organic waste bags, where they can be composted together with the food or green waste.
- Some trays and containers for fruit, vegetables, eggs and meat, bottles for soft drinks and dairy products and blister foils for fruit and vegetables are manufactured from bioplastics.
PERFORMANCE AND USAGE
- Many bioplastics lack the performance and ease of processing of traditional materials. Polylactic acid plastic is being used by a handful of small companies for water bottles, but shelf life is limited because the plastic is permeable to water - the bottles lose their contents and slowly deform.
- Bioplastics are seeing some use in Europe, though, where they account for 60% of the biodegradable materials market. The most common end use market is for packaging materials. Japan has also been a pioneer in bioplastics, incorporating them into electronics and automobiles.
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