Aliphatic-aromatic polyesters composting

Biomax. Biomax is a family of aliphatic/aromatic polyesters based on polyethylene terephthalate and manufactured by DuPont. A combination of hydrolysis and microbial action breaks down the polymer, and some grades have been certified as compostable. Reportedly, as many as three different proprietary aliphatic monomers may be incorporated into the polymer. ... 

The solution is a combination of aliphatic polyesters and aromatic polyesters. This involves modifying the crystalline structure of PBT by incorporating aliphatic monomer (adipic acid) in the polymer chain in such a way that the material properties of the polymer would remain acceptable (e.g., melting point of the crystalline range still around 100 °C), but the polymer would also be readily compostable/biodegradable. In this way it was possible to combine the degradability of aliphatic polyesters with the outstanding properties of aromatic polyesters. 

Ecoflex Aliphatic-aromatic co-polyester (BASF) Ahifor Compostable... 

Aromatic polyesters, such as PET, PBT or PEN, are not degradable in the presence of microorganisms, while their copolyesters with aliphatic acids show some extent of biodegradability [28,81,82]. It was reported that copolyesters based on PBT and polyfbutylene adipate) (PBA) with about 35-55 mol % of terephthalic acid residues exhibited suitable mechanical and physical properties, as well as favorable biodegradability (film approx. 100 pm degradation within 8-12 weeks in soil or compost). Beside copolymerization, the biodegradable properties of polyesters can be improved by increasing the hydrophilicity, for instance by the introduction of... 

BASF has introduced their aliphatic-aromatic copolyesters (AAC) product under the name Ecoflex . This material is widely used to produce compostable packaging and films. According to the BASF s corporate website, annual production of Ecoflex has risen to 60,000 MT to keep up with the demand for biodegradable plastics, which is growing at a rate of 20% per year. At the same time, BASF also produces a blend of polyester and PLA — a product called Ecovio . This high-melt-strength polyester—PLA can be directly processed on conventionally blown film lines without the incorporation of additives. Moreover, Ecovio has extraordinary puncture-and tear-resistance and weldability. Another company, Eastman, has also produced AAC, with the tradename Eastar Bio . Eastar Bio has a highly linear structure, while Ecoflex contains... 

FIGURE 19 Representative composting time (in months) of biopolymers (TPS - Thermoplastic starch, PC - Polycaprolactone, mc-PHA - medium chain length PHA, Al-co-PEs -Ahphatic co-polyester, PEA - Polyester amides, Ah/arocoPEs - Aliphatic/aromatic copolyester, and CDAc - Cellulose diacetate). 

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