Wankai's Key Achievement in Ton-Scale Production of 100% Bio-Based PEF

Developing 100% bio-based PET with superior performance to traditional PET has always been Wanke’s core focus, and this breakthrough is key to the industry's future progress.

PEF: A 100% Bio-Based Alternative to PET

Petroleum-based PET (Polyethylene Terephthalate) resin is made from 30% ethylene glycol (MEG) and 70% purified terephthalic acid (PTA). However, the rise in demand for sustainable, green plastics has driven the industry to explore bio-based alternatives. While bio-based PTA is commercially available, the efficient production of bio-based MEG remains a key challenge for large-scale bio-based PET plastic use.

Enter PEF, a promising bio-based polyester. PEF’s monomers, Furandicarboxylic Acid (FDCA) and ethylene glycol (EG), can both be sourced from renewable plant sugars, ensuring a more sustainable raw material supply.

PEF has quickly caught the attention of industry leaders, offering a powerful new solution for the green plastics sector. With the global push towards the UN’s Sustainable Development Goals (SDGs), particularly in reducing carbon emissions and plastic pollution, PEF’s future in the market looks highly promising.

In February 2023, Avantium, a Dutch company, signed a patent licensing deal with Eastman to accelerate the commercialization of PEF and FDCA. Avantium plans to launch its flagship FDCA plant in 2023, opening the door for large-scale PEF production.

PET vs PEF: Performance Comparison

1. Exceptional Barrier Properties  

PEF outperforms PET in barrier properties. Research by Eerhart et al. (2012) shows that PEF has 10 times better oxygen barrier, 6 to 10 times better carbon dioxide barrier, and twice the water vapor barrier compared to PET. This makes PEF an excellent choice for packaging, enhancing shelf life and reducing resource waste.

2. Superior Thermal Performance  

PEF has a glass transition temperature (Tg) of 86°C, higher than PET’s 74°C, and a melting point (Tm) of 235°C, slightly lower than PET’s 265°C. However, it still meets the thermal stability needs for most applications, especially in high-temperature environments.

3. Sustainability：PEF with Lower Carbon Footprint  

PEF’s carbon footprint is 50%-70% lower than PET, as confirmed by the U.S. Department of Energy. Its key raw material, furandicarboxylic acid (FDCA), is bio-based and can produce high-performance plastics, with FDCA recognized as one of the most promising bio-based chemicals.

4. Recyclability and Degradability

PEF is both recyclable and biodegradable. Research by Avantium and Amsterdam University (2019-2020) found that PEF can be used in PET bottles for up to five reuse cycles. It excels in multilayer and small packaging, replacing hard-to-recycle plastics. PEF also degrades faster than traditional plastics in industrial composting conditions and shows significant biodegradability in natural environments.

Challenges of PEF: Poor Toughness and Yellow Color

Currently, PEF faces two main challenges: poor toughness and yellowing. The main raw material, FDCA (furandicarboxylic acid), is a bio-based monomer derived from biomass like starch and cellulose. 

Compared to traditional petroleum-based PTA, FDCA has a similar structure but with oxygen atoms in its aromatic ring, making it more polar and more rigid due to a smaller bond angle between the ring and the carboxyl group. While PEF, made from FDCA and ethylene glycol, outperforms PET in heat resistance, mechanical strength, and gas barrier properties, the furan ring restricts the mobility of the molecular chains, which results in reduced toughness.

PEF is made through two methods: direct esterification and transesterification. In direct esterification, FDCA reacts with glycol at high temperatures (180-220°C), but this process causes FDCA to lose carbon dioxide, leading to a darker, brownish-yellow color. The transesterification method, which involves ester exchange followed by vacuum polycondensation, improves the color but doesn't completely solve the issue.

Wankai's Innovative Method for Producing Low-Color, Toughened PEF

Wankai New Materials has developed a simple yet highly effective process for creating low-color, toughened PEF, solving the issues of traditional methods that rely on side chains or extended polymerization times. This method offers significant technical advantages. The process involves the following steps:

First, a reaction system containing 2,5-furandicarboxylic acid (FDCA), epoxide, alkaline catalyst, and mixed solvent is used to initiate a reaction, forming an intermediate. The intermediate is then combined with a polymerization catalyst, stabilizers, and antioxidants, and undergoes polycondensation under vacuum at temperatures ranging from 220°C to 270°C, resulting in PEF.

During this process, the epoxide reacts quickly with FDCA at lower temperatures, minimizing decarboxylation reactions and improving the color quality of the polyester. Additionally, the alkyl-modified epoxide introduces side groups into the molecular chains, increasing the distance between molecules and enhancing their mobility, which significantly improves the toughness of the final polyester.

Comparison of Test Samples: Enhanced Color and Toughness in PEF

Polyfurandicarboxylic acid esters (e.g., Polyfurandicarboxylic acid 1,2-propylene glycol ester (PF-1,2-PG), Polyfurandicarboxylic acid 1,2-butanediol ester (PF-1,2-BD), Polyfurandicarboxylic acid 1,2-pentanediol ester (PF-1,2-PeD), Polyfurandicarboxylic acid ethylene glycol ester (PF-EG)) are derived from the reaction of FCDA with various alcohols. These esters can function as intermediates or modifiers in the production of PEF.

Compared to the esterification melting method used in Comparative Examples 1 and 2, the preparation method in this embodiment stands out for its ability to significantly reduce the color value of PEF. The b-value is notably lower, proving that this method effectively enhances the polyester's color quality.

Furthermore, by incorporating longer side chains, the synthesized furan-based polyester exhibits improved elongation at break, leading to a substantial increase in toughness. When compared to the PEF produced in Comparative Example 1, this method boosts both the toughness and durability of the polyester, highlighting the clear advantages of the invention.