The application of polymers (such as PCL, PGA and PLA) as biomaterials has had a profound impact on the progress of modern-day medicine, including their use in surgical sutures and implants. The use of biodegradable polymeric materials offers significant advantages such that they can be broken down and eliminated once their purpose is fulfilled. Copolymerization of their constitutive units offers the chance to tune the properties of the resulting polymers, such as rate of degradation, Young’s modulus, thermal transitions, and crystallinity. In general, high crystallinity together with high Tg, prevents easy deformability and high limit of elastic recovery.   
Applications in body parts with repetitive movements such as the heart or blood vessels require hyperelastic materials. Hyperelasticity is achieved through a combination of low Tg with a small number of crystallites as cross-links, as has recently been shown for blends of poly[(L-lactic acid)-co-(e-caprolactone)] (PLLAcoCL) and poly(D-lactic acid) (PDLA) [1]. In addition, these materials are degradable and hence may support tissue regeneration.   
However, degradation inevitably causes loss of their mechanical strength, as well as their hyperelasticity. It therefore needs to be ensured that this only occurs after the healing process is completed. Predicting the degradation rate of a material in the body is extremely challenging, as the body possesses and applies numerous defence mechanisms against foreign objects. Here, we therefore combine two degradation studies, one aiming at understanding the effect of hydrolytic chain fragmentation on the mechanical and thermal properties of the hyperelastic polymers, the other at understanding the influence of the material’s crystallinity on its susceptibility to different hydrolysis accelerating conditions.
The first set of experiments is conducted under simulated physiological conditions (pH=7.4, 37 °C) using 3D printed films and electrospun meshes. in various blends)   . The susceptibility tests were carried out in monolayers via the Langmuir technique [2] to test acidic, oxidative, enzymatic, and basic conditions while varying the content of PLA stereocomplex crystals through the PDLA content.
Hyperelastic PLLAcoCL/PDLA blends showed a relatively fast decrease of the molar mass under simulated physiological conditions, together with rapidly decreasing elongation and strain at break. After 9 weeks, when Mn was about 10 kDa, mass loss started to set in. At this point, the samples were not able to withstand any deformation anymore.
Altogether, the experiments help to understand and potentially predict the composition dependent material degradation of the discussed blends.