A model for simultaneous crystallisation and biodegradation of biodegradable polymers

Abstract

Biomaterials 2008;29:3393-3401). Crystallisation during biodegradation was not considered in the previous work which is the topic of the current paper. For many commonly used biodegradable polymers, there is a strong interplay between crystallisation and hydrolysis reaction during biodegradation -the chain cleavage caused by the hydrolysis reaction provides an extra mobility for the polymer chains to crystallise and the resulting crystalline phase becomes more resistant to further hydrolysis reaction. This paper presents a complete theory to describe this interplay.The fundamental equations in the Avrami's theory for crystallisation are modified and coupled to the diffusion-reaction equations that were developed in our previous work.The mathematical equations are then applied to three biodegradable polymers for which long term degradation data are available in the literature. It is shown that the model can capture the behaviour of the major biodegradable polymers very well.

Mechanical study of PLA–PCL fibers during in vitro degradation

“…The parameters in such a model require extensive experimentation. Modern numerical techniques have been used (Göpferich and Langer, 1993;Wang et al, 2008;Yu et al, 2008;Han and Pan, 2009;Bikiaris et al, 2007;Metzmacher et al, 2007) to solve the corresponding equations for devices of both simple and complicated geometries, in the context of drug release devices. However, none of these models were able to predict the mechanical properties evolution of the device.…”

An atomic finite element model for biodegradable polymers. Part 2. A model for change in Young’s modulus due to polymer chain scission

“…10 (e), it can be seen to achieve quite a good fitting, using the same volume of effective cavity. (Gleadall et al, 2012;Han and Pan, 2009;Han et al, 2010), to give a combined model for molecular weight, crystallinity and Young's modulus throughout degradation.…”

Mechanical, rheological, fatigue, and degradation behavior of PLLA, PGLA and PDGLA as materials for vascular implants

“…recombination of monomers released due to degradation and formation of longer polymer chains. As a result, there is an improvement of the output mechanical properties of the material [25]. In subsequent months the mechanical properties of PLLA gradually decline until total physical degradation of the specimens prevents mechanical tests on the 25th month of incubation.…”