Question

You are producing a new, resorbable web to be used in-vivo as a woven mesh to reinforce hernia repairs. You are exploring polymers comprised l-lactic acid, d-lactic acid and glycolic acid and have spun a variety of polymers comprising these monomers, including the homopolymers of each. To be effective the glass transition of the fibers should be above body temperature and you would like the fibers to be semi-crystalline to control the resorption rate (the higher the crystallinity the slower the resorption). Key properties in your product specifications are low (<3%)water uptake after one day in-vivo (simulate with incubation media) use and must not shrink more than 5% during storage – the product is being used by the military so the temperature of storage may be as hot as 110C or as low as -20C. You have a suite of Thermal Analysis instruments at your disposal including a DSC, a TMA and a TGA connected to a GC-MS. How would you measure:

1. The glass transition temperature and the melting temperature of the fibers?

2. You allow your melted sample to recrystallize in the instrument and remelt it, would you expect the measured phase change parameters to change?

3. The dimensional stability of the fibers relevant to the potential storage conditions?

Answer 1