Studies on the effect of stereoregularity and chain branching on thermal properties of multiple steam sterilized poly(vinyl chloride)

Abstract

Multiple steam sterilization drastically affects the micromorphology of poly(vinyl chloride) (PVC). Stereoregularity as well as chain branching of sterilized PVC samples varies in covered and uncovered samples. Attenuated total reflectance (ATR) spectral studies confirm these variations which are exhibited by the peaks at 1428 cm−1 and 1434 cm−1 for stereoregularity and by the peak at 1378 cm−1 for chain branching. Differential scanning calorimetry (DSC) studies of sterilized samples indicate that the changes in the glass transition temperature (Tg) are not linear with the changes in syndiotacticity. Variation in the length of chain branches have a predominant effect over the variations in syndiotacticity: short chain branches and long chain branches offer higher and lower Tg, respectively, though the degree of syndiotacticity is the same in both cases.

Effect of steam on the structural and morphological stability of renewable poly(ether‐block‐amide)s

“…18 Chemically stable polymers can also undergo changes in the surface morphology, especially if the glass transition temperature of the polymer is exceeded while autoclaving. 19,20 Moreover, autoclaving was also found to change the mechanical properties 21 of polymeric materials due to rearrangement of macromolecular chains, giving rise to chain branching 22 or to modification in the crystalline structure. 23,24 The effect of both heat and steam after autoclaving renewable PEBAs is not reported with relation to biomedical and clinical practice.…”