Development of bio-based polymers is accelerating in response to mounting consumer pressure and legislation, but costs of these different processes and the resulting product properties vary, impeding growth of the sector, as per a new IHS Chemical report. Bio-based polymers, which are also referred to as bioplastics or biopolymers, are materials produced from renewable resources. Renewable raw materials for biobased polymers include sugar and starch bio-products - seed oil and lipid-based bio-products, cellulose derivatives, protein and biomass. Starch sources vary worldwide, but include corn, potatoes, cassava and sugar beets. The remaining portion of the polymers may be from fossil-fuel-based carbon. Bio-based polymers generally have a lower CO2 footprint and are associated with efforts to create more sustainable, environmentally friendly products. Currently, most bio-based polymers are natural rubber and cellulosic materials. Natural rubber, cellulosic materials, cellulose acetate/triacetate and Nylon-11 are long established products with mature markets. In 2012, the two most important commercial biodegradable polymers were polylactic acid (PLA) and starch-based polymers, accounting for about 47% and 41%, respectively, of total biodegradable polymers consumption. These polymers are both bio-based and biodegradable. “While bio-based polymers currently comprise less than 1% of the total global polymer market, there is significant consumer demand and that demand, combined with increasing legislation such as plastic bag bans and global warming initiatives, are driving increased market opportunity for bio-based plastics,” said Susan L. Bell, author of the study and a principal analyst at IHS Chemical. “At present, however, wide-scale commercialization of some of these technologies is being limited by significantly higher costs when compared to traditional, petroleum-based plastics, and in some cases, by product quality.”
The development of commercial routes to new, bio-based feedstocks, has, in turn, accelerated the development of biobased polymers. For example, bio-based polycarbonate (PC) is of interest to several companies, including Japanese-based Mitsubishi Chemical, in collaboration with French-based Roquette. A bio-based polycarbonate, Durabio� has been developed using sugar-derived isosorbide as a monomer. Isosorbide polycarbonate is reported to have different properties than polycarbonate based on bisphenol A (BPA), the most widely used engineering plastic, which in 2012, had a global demand of nearly 3.7 mln metric tons. “A limited quantity of isosorbide polycarbonate - just 300 metric tpa, is currently being produced through this venture, but there are plans to expand that production to 20,000 metric tpa by 2015. The analysis revealed overcoming high costs will be a challenge, even once the process is commercialized at a scale comparable to world-scale production of BPA-based polycarbonate. However, for other plastics-based products such as polybutylene succinate (PBS), the bio-based alternatives are actually less costly than the petroleum-derived standards. PBS is a biodegradable polyester produced from 1, 4-butanediol (BDO) and succinic acid. It has properties similar to polyethylene terephthalate (PET), a polymer resin used in synthetic fibers, such as polyester, in food and beverage containers, and for engineering applications. Today, the monomers are typically produced from petroleum-based resources. The current PBS market is small because of the relatively high costs of PBS. However, with the recent development of bio-based succinic acid and bio-based BDO, PBS can be produced using renewable feedstock, and several companies are now developing bio-based PBS. Mitsubishi Chemical, for example, is collaborating with BioAmber (for bio-based succinic acid feedstock) and Genomatica (for bio-based BDO feedstock). A PBS plant that will produce 20,000 metric tpa is being built in Thailand, with completion expected in 2014. Based on the HIS Chemical techno-economic analysis, bio-based PBS has substantially lower net-production costs than petroleum-based PBS, so this is a situation where the bio-based alternative is a more cost-effective solution for producers. Another process the report assessed was the economics of polyethylene, the world’s largest-volume plastic. Traditionally produced from fossil fuels, bio-based ethylene was the first commodity bio-based polymer to enter the commercial market, with commercial production started in 2010. Brazil’s Braskem is the largest producer of bio-based polyethylene, relying on sugarcane to produce the ethanol that is dehydrated to form the ethylene base. Said Bell, “The ‘green’ polyethylene marketed by Braskem has the same performance characteristics as petroleum-based polyethylene, but based on our estimate, ethylene derived from ethanol (from milled Brazilian sugar cane), is substantially more costly than ethylene derived from ethane, which has seen a dramatic price drop due to the ethane feedstocks resulting from increased North American gas supplies. Currently, the green polyethylene commands a price premium of approximately 15-20% above petroleum-based polyethylene, which represents a significant cost difference.”
According to a related IHS report, demand for biodegradable polymers (plastics) in North America, Europe and Asia will increase from 269,000 metric tons (MT) in 2012 to nearly 525,000 MT in 2017, representing an average annual growth rate of nearly 15% during the five-year period 2012-2017. This report focused on biodegradable polymers, including compostable materials, but not necessarily including all bio-based products Biodegradable polymers are a part of the larger overall bioplastics/biopolymer market. Typically, bioplastics are either bio-based or biodegradable, although some materials are both.