June 1, 2018 is the tenth year for China to implement the plastic restriction order. Can you tell me which countries in the world have implemented the plastic restriction order?
At present, more than 40 countries and regions have made regulations on the use of plastic bags, including three kinds of policies: prohibition, partial prohibition and restricted use.
Plastic reduction policies in Europe and the United States continue to strengthen. The European Union recently announced that it will recycle or reuse plastic packaging by 2030, but most European countries are only at the level of consumers’ voluntary reduction. France’s plastic restriction order was upgraded at the beginning of this year, and all cosmetics containing plastic particles will be taken off the shelves. From 2020, household plastic cotton swabs and disposable plastic tableware will also be banned. At the beginning of this year, the UK proposed to ban plastic bags, bottles, plastic straws and other products within 25 years. In the United States, only California has banned plastic bags, while other cities need to pay for paper or plastic bags.
At present, more than 12 of the 54 countries in Africa have introduced plastic limit policies. Eritrean government banned plastic bags as early as 2005. Other countries include Tanzania (2006), Uganda (2007), Rwanda (2008), Mauritania (2013), Morocco (2016), Senegal (2016), Somaliland (2017), Tanzania (2017) and Kenya (2017). If these countries want to completely ban plastic bags, or ban the manufacture, sale and use of plastic bags, the punishment will be stronger 。
The Asian plastic restriction order is quite effective. In 2002, Bangladesh became the first country in the world to ban plastic bags. Mumbai, India, banned the use of plastic bags less than 0.05mm in thickness in 2016, and Sri Lanka also banned plastic bags, plastic plates and plastic cups. The plastic restriction policies of Southeast Asian countries are different. The government of Rangoon, the capital of Myanmar, banned the manufacture, sale and storage of plastic bags; Malaysia announced in 2017 that the federal region banned the use of general plastic bags. Other regions, such as Japan, have announced that all retail stores will ban the provision of free plastic bags from 2020. In 2008, China banned the provision of free plastic bags, the manufacture, sale and use of plastic bags less than 0.025mm in thickness. The South Korean government decided in 2018 that large supermarkets would ban disposable plastic bags.
A significantly growing interest is to design new biodegradable polymers in order to solve fossil resources and environmental pollution problems associated with conventional plastics. A kind of new biodegradable polymers, aliphatic–aromatic co-polyesters have been researched widely and developed rapidly in recent years, since that can combine excellent biodegradability provided from aliphatic polyesters and good properties from aromatic polyesters. Out of which, poly (butylene-adipate-co-terephthalate) (PBAT) shows the most importance. PBAT has been commercialized by polycondensation reaction of butanediol (BDO), adipic acid (AA) and terephthalic acid (PTA) using general polyester manufacturing technology. And it has been considered to have desirable properties and competitive costs to be applied in many fields. Therefore, this review aims to present an overview on the synthesis, properties and applications of PBAT.
Is PBAT toxic? While PBAT is incredibly biodegradable and will decompose in home compost leaving no toxic residues, it is currently partly derived from petrochemicals, yip, oil. … Interestingly, it is PBAT that is added to make the product degrade quickly enough to meet the home compostability criteria.
What is PBAT and PLA? Biodegradable polymers as poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are thermoplastics which can be processed using the most conventional polymer processing methods. PLA is high in strength and modulus but brittle, while PBAT is flexible and tough.
Is PBAT biodegradable? Poly(butylene adipate-co-terephthalate) (PBAT) is a well-known biodegradable plastic. It is a flexible material, and has a high elongation at break, as well as good hydrophilic and processing properties.
What is PBAT material? PBAT (polybutyrate adipate terephthalate) is a biodegradable random copolymer. The co-polyester of adipic acid, 1,4-butanediol and dimethyl terephthalate is available commercially as resin and as compound with PLA or starch. As a “drop-in” polymer, PBAT resembles LDPE in its properties.
In the 21st century, as one of most important materials, conventional plastics have been developed rapidly and utilized widely in varieties of fields because of their excellent comprehensive properties and low costs. Unfortunately, most of these conventional plastics, such as polyethylene (PE), polypropylene (PP) and polystyrene (PS) etc., come from petroleum origin and their wastes cannot be degraded. So the increase in the production and consumption of conventional plastics, as a consequence, results in the increase of oil consumption and serious environmental pollution. Fossil resources and environmental pollution, as the major problems caused by conventional plastics, should be solved for sustainable development in future.
The overall strategy to solve these difficult problems on fossil resources and environmental pollution should be through recycling wasted conventional plastics and using biodegradable plastics together. The serious problems could not be solved by means of conventional plastic recycling alone, because it is not always possible to recover all the used plastics. A considerable amount of wasted plastics are eventually destined to be burnt or buried in land during recycling processes of wasted plastics, whether physical or chemical recycling. In such situation, it is one effective way and beneficial supplement for solving these plastic problems to use biodegradable plastics, compared to plastic recycling. A biodegradable plastic is one that undergoes decomposition due to the action of naturally occurring microorganisms such as fungi, algae and bacteria. Take these into consideration, the necessity of biodegradable plastics can be easily understood that their wastes can be recovered by microorganisms under natural environment. In fact, biodegradable plastics have become increasingly popular all over the world, because biodegradable plastics have been put into effect in solving these plastic problems with their rapid developments and wide applications in recent years.
The market for biodegradable plastics has also shown strong growth during the last two decades. In 2005 the global biodegradable plastics market tonnage was estimated at 94,800 tones and in 2010 the market reached the 214,400 tones, which represents a compound annual growth rate of 17.7% during the period 2005–2010. Packaging (including rigid and flexible packaging, paper coating, and foodservice) consumes about the 39% of the total biodegradable polymer market volumes, followed by loose-fill packaging (about 24%), bags and sacks (21%), fibers (9%), and others (7%). Consequently, there is a strong demand to design and improve biodegradable plastics that are not only biodegradable but also meet the requirements of expected material properties.
To solve the environmental problems and meet the market demand, there is a growing interest in designing new biodegradable polymers which are the foundation of biodegradable plastics. During developing biodegradable polymers, polyesters are a particularly interesting group of polymers.On one hand, aliphatic polyesters have been shown to be easily biodegradable because of their ester bonds in the soft chain, which are sensitive to hydrolysis. Unfortunately, aliphatic polyesters like poly-caprolactone (PCL) and poly-β-hydroxybutyrate (PHB), show poor mechanical and thermal properties. On the other hand, aromatic polyesters like Polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), exhibit very good physical properties but strong resistance to attack by microorganisms. Therefore, in order to design new polyesters having both satisfactory mechanical properties and desirable biodegradability, some aliphatic-aromatic co-polyesters consisting of aliphatic and aromatic units have been synthesized and researched.
Among numerous aliphatic-aromatic co-polyesters, the most promising and popular one with potential development prospects in a wide range of applications is poly (butylene adipate-co-terephthalate) (PBAT), obtained by poly-condensation between butanediol (BDO), adipic acid (AA) and terephthalic acid (PTA). It has been turn out to be the most appropriate combination, regarding excellent properties and good biodegradability. The commercially available aliphatic-aromatic co-polyester PBAT is list in Table 1. Therefore, the scope of this review is a comprehensive summary of currently available results about the synthesis, properties and applications of PBAT.
Major commercially available Co-polyester PBAT.
| Company | Country | Brand name | Capacity (t/y) |
|---|
| BASF | Germany | ECOFLEX® | 60,000 |
| KINGFA | China | ECOPOND® | 50,000 |
| NOVAMONT | Italy | Origo-Bi® | 40,000 |
| TUNHE | China | – | 30,000 |
| XINFU | China | – | 20,000 |
| JINHUI | China | ECOWORD® | 20,000 |
| Junyuan | China | – | 20,000 |
Mechanical properties
PBAT shows not only good biodegradability due to the aliphatic unit in the molecule chain, but also excellent mechanical property thanks to the aromatic unit in the molecule chain. Compared to most biodegradable polyesters such as poly (lactic Acid) (PLA) and poly (butylene-co-succinate) (PBS), the mechanical properties of PBAT show more flexible, and are similar to those of low-density PE (LDPE). These mechanical properties make PBAT a very promising biodegradable material for a wide range of potential applications.
The mechanical properties of PBAT.
| Properties | Test method | Test Condition | Units | PBAT |
|---|
| Mechanical Properties |
| Tensile Strength | ASTM D638 | 50 mm/min | MPa | 21 |
| Elongation at break | ASTM D638 | 50 mm/min | % | 670 |
| Flexural Strength | ASTM D790 | 2 mm/min | MPa | 7.5 |
| Flexural Modulus | ASTM D790 | 2 mm/min | MPa | 126 |
| Thermal Properties |
| Melt point | DSC | 10 °C/min | °C | 115–125 |
| Crystallization point | DSC | 10 °C/min | °C | 60 |
| 5% weight loss temperature | TG | 20 °C/min | °C | 350 |
| Heat Distortion Temp. | ASTM D648 | 1.82 MPa,6.4 mm | °C | 55 |
| Other Properties |
| Melt Flow Index | ASTM D1238 | 190 °C, 2.16 Kg | g/10min | 4.0 |
| Specific Gravity | ASTM D792 | 23 °C | g/cm3 | 1.22 |
Application of PBAT
For about past two decades, vast amount of research is being carried in the field of PBAT, which illustrates its significance. However, research and development is just part of a product life cycle. The real product starts when the sciences being applied to a specific application. Thus, the product process introduces a new material into the market. Now the development state of PBAT is under more and more applications into the market. Many products based on PBAT have been applied into many fields such as shopping bags, garbage bags, cutlery and mulch film etc. And out of which, two applications is select to be introduce in the details in this text, one is packaging aimed to the recent market, and the other is mulch film aimed to the future market.
Packaging
Conventional plastic packaging is widely used in a number of consumer goods and garbage collection applications due to its good properties and low cost compared to other packaging materials. In past ten year, around 14 million tons of conventional plastic packaging waste was generated each year, out of which only 1.6 million tons was recovered through recycling and the rest of which ended up in landfills. In efforts to reduce conventional plastic packaging, one of the recovery techniques is composting using the biodegradation process. As a result, a number of biodegradable PBAT-based materials are being commercialized that are compostable. Packaging based on these materials has currently gained great attention in many disciplines because of unique properties when compared to conventional plastic materials. There are a number of commercially available compostable PBAT-based materials that could be further processed to make a package for desired applications. Some of the notable companies that have been developing PBAT-based materials are BASF, Novamont, Junyuan, BIOTECH and KINGFA etc. As one of the world leaders in biodegradable plastics, KINGFA has developed several compostable materials based on PBAT, starch and PLA etc. These materials have found several applications in packaging especially in shopping bags, compost bags etc., as exhibit in. The shopping bags supervised by KINGFA based on Starch-PBAT blends have been widely used in high-level supermarkets in China, which has become a model for the application of biodegradable plastics in China.
Some applications of PBAT based products
Mulch film
Modern agriculture heavily relies on the use of conventional plastic mulch films, because these films can raise crop yields through elevating soil temperatures, conserving soil moisture, controlling weed growth and providing protection against severe weather and pests. The global agricultural film market is predicted to reach an annual volume of 7.5 million tons by 2021, and China uses the most PE mulch film with 1.5 million tons annually. After these PE mulch films have been used up, it is hard to recovery them from agricultural fields completely, due to PE film embrittlement and fragmentation caused by weathering, particularly when thin films are used. Residual PE films enter and subsequently accumulate in agricultural soils, as results, which decrease soil productivity by blocking water infiltration, impeding soil gas exchange, constraining root growth, and altering soil microbial community structures. A promising approach to overcome the accumulation of residual PE mulch films in soils is to replace the conventional with biodegradable mulch films composed of polymers designed to be degradable by soil microorganisms. Biodegradable mulch films placed in the soil are susceptible to ageing and degradation during their useful lifetime, so they need to have some specific properties. PBAT based mulch films have been developed by KINGFA to meet agricultural requirements, as exhibit in. When applied in soil, PBAT based mulch films can be little affect by water, high temperatures and UV radiation during their useful lifetime and can be biodegradable completely after their useful lifetime. The agricultural films manufactured by KINGFA and Junyuan based on PBAT/PLA/Nano-particles composites have been applied and achieved positive results in many regions and crops in China, which build a good foundation for the further developments in China.
Conclusions
The indiscriminate use of conventional plastics has brought about significant environmental problems, which has led to increased interest in biodegradable plastics, especially PBAT based biodegradable plastics that can offer a number of benefits in environmental conservation due to their biodegradability. So the important issues about PBAT such as synthesis, properties, composites and applications are discussed in this review. PBAT can be easily synthesized using conventional polyester manufacturing technology, which make it can be possible to obtain sufficient capacity for PBAT in a short term. Since PBAT shows not only good biodegradability but also excellent properties, PBAT can be applied in many fields, especially in package and mulch film application. So PBAT is considered to be one of the most promising biodegradable polyesters.
In the future, conversion of biomass components into PBAT is one of the promising and economical techniques to overcome fossil fuel crisis. Firstly, bio-based BDO has been obtained through industrial biological fermentation to replace of petrochemical BDO in PBAT directly. Secondly, sebacic acid, as a substitute of AA, coming from castor oil has been used as monomer to prepare poly (butylene sebacinate-co-butyleneterephthalate) (PBSeT) co-polyesters. Finally, 2, 5-furandicarboxylic acid (FDCA) has been regarded as one of the most high-potential bio-based aromatic monomers. It is a perfect bio-based alternative to the petroleum-based PTA. Hence, it is foreseeable that whole bio-based aliphatic-aromatic co-polyesters will be formed in a few years.