Morphology and conductivity changes in a thermoplastic polyurethane‐based copolymer consisting of different soft segments

Abstract

Three different segmented thermoplastic polyurethanes (TPUs) were synthesized with 4,4Ј-methylenebis(phenyl isocyanate) as a hard segment and poly(ethylene glycol) (PEG) or poly(propylene glycol) (PPG) or an equal mixture of PEG and PPG with molecular 2000 as soft segments. The soft-segment component of TPU was changed to monitor modifications in chemical and physical properties among the three TPUs. Differential scanning calorimetry (DSC) and thermogravimetric analysis were used to monitor changes in thermal characteristics. Fourier transform infrared spectroscopy (FTIR) was employed to predict the interaction between the lithium cation and the hard or soft segment in the presence of added LiClO 4 . The deconvolution results of spectral bands associated with the NOH groups of these TPUs were used to obtain such information. Impedance spectroscopy was used to inspect the changes in the bulk conductivity of these TPUs caused by alteration of the soft-segment component. The conductivity changes were explained through combined DSC and FTIR results. The electrochemical stability of the TPU systems was studied by linear sweep voltammetry. The results showed that the copolymer system had better thermal and electrochemical stability than the other systems.

Novel polymer electrolytes based on thermoplastic polyurethane and ionic liquid/lithium bis(trifluoromethanesulfonyl)imide/propylene carbonate salt system

“…This is in agreement with observations of other authors, which indicate that in gel electrolytes obtained by impregnation with PC the charge transport becomes highly decoupled from motions of the polymer matrix [13,15,44]. In some cases, a slight bending of the dependence was observed at around 10 • C (more evident in the electrolytes with 56 and 70 wt% of MIX).…”

“…However, in case of gel electrolytes obtained by the impregnation of TPU with propylene carbonate (PC), most authors reported Arrhenius-type dependence [13,15,44]. This effect is believed to be associated with the improvement of salt dissociation as well as weakening of interaction between charge carriers and polymer matrix in the presence of PC.…”

Electrical conductivities and Li ion concentration-dependent diffusivities, in polyurethane polymers doped with lithium trifluoromethanesulfonimide (LiTFSI) or lithium perchlorate (LiClO4)

“…Solid State Ionics j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / s s i is believed to take place almost entirely in the amorphous phase of a polymer matrix [10,11]. However, some reports have concluded that both soft and hard segments play a significant role in ionic transport [12].…”

High clarity poly(caprolactone diol)-based polyurethane adhesives for polycarbonate lamination: Effect of isocyanate and chain-extender

“…The first of these peaks was fitted between 3400 cm -1 -3650 cm -1 to determine the free N-H groups, a second peak is fitted between 3340 cm -1 -3400 cm -1 to account for the carbonyl overtone and a final peak is fitted between 3250 cm -1 -3340 cm -1 to determine the contribution from hydrogen bonded N-H groups. 26 Once analysis was complete, the ratio of hydrogen bonded N-H groups to free N-H groups can be obtained. Following chain-extension, the ratio decreased from 7:1 for TMP-only to What influence greater phase mixing has on the adhesion and clarity will be discussed within section 3.3.…”

“…Further information on the microphase morphology is obtainable from deconvolution of the carbonyl region. 25,26 The position of the peak labelled ester within table 6, will contain bands from both free urethane and free PCD ester groups which occupy the range 1740 cm -1 -1730 cm -1 . Of these functionalities, the ester will be dominant and any changes to the environment of these groups will lead to a noticeable change to the peak shape.…”