The cheapest degradable polymer available today is Polybutylene adipate terephthalate (PBAT). PBAT is a type of biodegradable polyester that combines polybutylene adipate and terephthalate segments. It is an eco-friendly alternative to traditional petroleum-based plastics and is gaining popularity due to its low cost and degradability.

PBAT is commonly used in various applications such as packaging films, agricultural mulch films, and disposable products. Its low cost is primarily attributed to the availability and cost-effectiveness of its raw materials. The production of PBAT involves the use of adipic acid, terephthalic acid, and 1,4-butanediol, which are relatively inexpensive compared to other bio-based polymers.

Aside from being the cheapest degradable polymer, PBAT has several advantages that contribute to its growing demand. One of its key features is its biodegradability. PBAT can be broken down by microorganisms in the environment into carbon dioxide, water, and biomass within a reasonable timeframe. This characteristic makes it an excellent alternative to conventional plastics that can persist in the environment for hundreds of years.

Another advantage of PBAT is its flexibility and versatility. It can be processed using conventional plastic processing techniques, such as injection molding and blown film extrusion. This makes it suitable for a wide range of applications, from packaging to agricultural films. PBAT also exhibits good mechanical properties, including high elongation at break and good impact resistance.

Furthermore, PBAT films have good barrier properties, providing protection against oxygen and moisture. This makes it ideal for packaging perishable goods, as it helps to extend their shelf life. PBAT films can also be printed on, allowing for attractive and informative packaging designs.

In addition to its cost-effectiveness and physical properties, PBAT is also considered to be a sustainable polymer. It is derived from renewable resources such as vegetable oil, and its production consumes less energy compared to petroleum-based polymers. Moreover, the use of PBAT reduces the dependency on fossil fuels and contributes to the overall reduction of carbon emissions.

Despite its many benefits, PBAT does have some limitations. Firstly, the rate of degradation depends on environmental conditions such as temperature and moisture. It may take several months to a few years for PBAT to fully degrade, depending on the disposal conditions. Additionally, PBAT is not recyclable in traditional plastic recycling systems and requires dedicated composting facilities for proper disposal.

In conclusion, Polybutylene adipate terephthalate (PBAT) is currently the cheapest degradable polymer available. Its low cost, combined with its biodegradability, versatility, and environmental advantages, make it an attractive choice for various applications. However, it is essential to note that while PBAT offers a more sustainable alternative to traditional plastics, proper disposal methods and infrastructure are crucial for maximizing its environmental benefits.