The Korea Research Institute of Chemical Technology (KRICT) has developed a bio-polycarbonate which has been monopolized by Japan, and has opened up the possibility of bio-polycarbonate commercialization.
Bio-polycarbonate is an eco-friendly bio-plastic that can replace conventional polycarbonate, which contains the environmental hormone causing substance, bisphenol A (BPA). Until now, Mitsubishi Chemical Corp. of Japan is the only company to successfully commercialize production of bio-polycarbonate.
Dr. Jeyoung Park, Dr. Dongyeop Oh, and Dr. Sung Yeon Hwang of the Research Center for Bio-based Chemistry of KRICT utilized the plant-based components of isosorbide and nanocellulose to develop the bio-polycarbonate.
BPA is a petrochemical substance and an environmental hormone that causes endocrine disruptions and metabolic complications. It is mostly used in polycarbonate, and the usage of this substance is prohibited in milk bottles and cosmetics in Korea. It is also used in receipt papers and the coating materials of canned foods.
For that reason, bio-polycarbonate has received attention as an alternative to polycarbonate containing BPA. However, it is difficult to simultaneously satisfy both economic feasibility and high mechanical performance of general plant-ingredient plastics. KRICT overcame this problem with the combination of isosorbide and nanocellulose, and succeeded in producing bio-polycarbonate that surpasses petroleum-based polycarbonate.
Isosorbide, an eco-friendly compound derived from glucose, not only improves the mechanical properties of the incorporated polymer, but also possesses good optical and UV-resistive properties due to its unique molecular structure.
The research team applied the principle of “like dissolves like” where similar compounds mix together better. Isosorbide well mixed together with nanocellulose as a bio-derived reinforcing agent because both substances are hydrophilic and have a similar structure. Then, the polymerization process of the nanocomposite plastic was carried out. The well dispersed nanocellulose acted like metal rebar in concrete and thus maximized the strength of the bio-plastic.
Dr. Jeyoung Park of KRICT said, “We wanted to break the stereotype that bio-plastic has inferior mechanical properties and is expensive.” Dr. Park continued, “Through the synergistic interplay between the plant-based ingredients, we were able to develop a bio-plastic that is superior to petroleum plastic.” As a result, it significantly improved the physical properties of the bioplastic such as strength and transparency, which have been pointed out as limitations of general bio-plastics.
The developed bio-polycarbonate exhibited a tensile strength (how strong a material is) of 93 MPa. This is the highest measurement to date amongst existing petroleum and bio-polycarbonates. The tensile strength of petroleum polycarbonate ranges from 55 – 75 MPa, while the tensile strength of the bio-polycarbonate of the Japanese firm Mitsubishi Chemical Corp. is 64 – 79 MPa.
Read more: Alternative for petroleum polycarbonate
Image courtesy of phys.org