Forecasting the hydrolysis of poly(butylene succinate) depending on molecular mass and temperature in soil and aquatic systems validated on the example of a football hybrid turf

For maintenance and water saving reasons artificial or semi-artificial (hybrid) turfs have worldwide replaced natural turfs in many football-, soccer- and hockey stadiums. For obvious sustainability reasons the polymers which replace or reinforce the natural grass should be degradable, but still maintain specific mechanical properties over a certain period of time. This study intends to design and validate a poly(butylene succinate) (PBS) which fulfils these requirements. We investigated the dependency of PBS hydrolysis on molecular mass and temperature in order to develop a kinetic model for abiotic hydrolysis, which is the limiting step in PBS biodegradation. The hydrolysis rates were found to be temperature dependent according to the Arrhenius relationship [Formula presented]. A molecular mass dependency of the pre-exponential factor A was established and could be fitted well by a linear equation without intercept for higher molecular weights. A polynomial approach led to a better fit for the whole molecular weight range. Both models have been validated on a degradation experiment in soil and were able to predict the molecular mass degradation within the typical standard deviations by size exclusion chromatography. Furthermore, we used the models to simulate the degradation of PBS samples in soil on available long-term soil temperature data. Previously published data on the relationship between molecular weight and mechanical properties were used to forecast the loss of functionality. This prediction was then compared to traction tests of aged PBS filaments used as fibre reinforcement of football hybrid turfs. The measurements match the predictions and show that a hybrid turf system with PBS fibres can be played on for at least 5.2 years before the fibres lose their mechanical properties.