TY  - JOUR
A1  - Hoffmann, Falk
A1  - Machatschek, Rainhard Gabriel
A1  - Lendlein, Andreas
T1  - Analytical model and Monte Carlo simulations of polymer degradation with improved chain cut statistics
JF  - Journal of materials research : JMR
N2  - The degradation of polymers is described by mathematical models based on bond cleavage statistics including the decreasing probability of chain cuts with decreasing average chain length. We derive equations for the degradation of chains under a random chain cut and a chain end cut mechanism, which are compared to existing models. The results are used to predict the influence of internal molecular parameters. It is shown that both chain cut mechanisms lead to a similar shape of the mass or molecular mass loss curve. A characteristic time is derived, which can be used to extract the maximum length of soluble fragments l of the polymer. We show that the complete description is needed to extract the degradation rate constant k from the molecular mass loss curve and that l can be used to design polymers that lose less mechanical stability before entering the mass loss phase.
KW  - Modeling
KW  - Degradable
KW  - Polymer
KW  - Molecular weight
KW  - Simulation
Y1  - 2022
U6  - https://doi.org/10.1557/s43578-022-00495-4
SN  - 0884-2914
SN  - 2044-5326
VL  - 37
IS  - 5
SP  - 1093
EP  - 1101
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Izraylit, Victor
A1  - Liu, Yue
A1  - Tarazona, Natalia A.
A1  - Machatschek, Rainhard Gabriel
A1  - Lendlein, Andreas
T1  - Crystallization and degradation behaviour of multiblock copolyester blends in Langmuir monolayers
JF  - MRS communications / a publication of the Materials Research Society
N2  - Supporting the wound healing of soft tissues requires fixation devices becoming more elastic while degrading. To address this unmet need, we designed a blend of degradable multiblock copolymers, which is cross-linked by PLA stereocomplexation combining two soft segments differing substantially in their hydrolytic degradation rate. The degradation path and concomitant structural changes are predicted by Langmuir monolayer technique. The fast hydrolysis of one soft segment leads to a decrease of the total polymer mass at constant physical cross-linking density. The corresponding increase of the average spacing between the network nodes suggests the targeted increase of the blend's flexibility.
KW  - Degradable
KW  - In situ
KW  - Microstructure
KW  - Thin film
Y1  - 2021
U6  - https://doi.org/10.1557/s43579-021-00107-y
SN  - 2159-6859
SN  - 2159-6867
VL  - 11
IS  - 6
SP  - 850
EP  - 855
PB  - Springer
CY  - Berlin
ER  -