Morphology and Mechanical Properties of Thermoplastic Polyurethanes Containing Polyisobutylene/Poly(tetramethylene oxide) Mixed Segments

Abstract

We investigated the thermal properties, microphase separated structure and mechanical properties of a series of thermoplastic polyurethanes (TPUs) containing both polyisobutylene (PIB) and poly(tetramethylene oxide) (PTMO) diols in the soft segment (SS). A series of TPUs were prepared with the same weight fraction of the SS but different ratio between PIB and PTMO diols. Molecular weight of the PTMO diol and chemical structure of the hard segment (HS) also varied. Dynamic mechanical analysis (DMA) measurements did not reveal strong microphase separation between PIB and PTMO in the SS. While it has been assumed that incorporating PTMO diol into the SS can enhance the phase mixing between the hard segment (HS) and SS, our results indicated that, in most cases, the degree of microphase separation of TPUs based on mixed diols is slightly higher than that of TPUs based on only PIB diol.

Current progress towards understanding the biodegradation of synthetic condensation polymers with active hydrolases

“…This fact is most likely due to the availability of commercial polyesters and their defined composition compared to the protected information surrounding commercial polyurethane formulations. Polyurethane copolymers are more complex and can result in complex phase separations, [98][99][100] which we believe is the reason why experiments designed for polyurethanes are only observed in more applied research and screening. For example, almost all papers dealing with polyurethanes describe the degradation of commercial polymer films, 101-103 foams [104][105][106] and paints [107][108][109] instead of identifying the underlying mechanisms of degradation.…”

Molecular dynamics study of the linear viscoelastic shear and bulk relaxation moduli of poly(tetramethylene oxide) (PTMO)

“…The hard segments are generally rigid and obtained by reaction of diisocyanates with diol/diamine chain extenders and include strongly hydrogen bonded urethane or urea groups. The soft segments consist of relatively flexible polyamine/polyol chains in which the hard domains are embedded and act as a flexible continuous matrix for the network of hard domains 16,17 . The poly(tetramethylene oxide) (PTMO) is widely used as the soft segment in segmented block copoly(ether ester) PU, contributing to the microphase segregation of polyurethane elastomers [18][19][20][21] .…”