writer：Yuntong, Li Liu*, Yongri Liang*
keywords：Polyurethane, bi-soft segment, dynamic mechanical property
source：期刊
specific source：J Appl Polym Sci. 2020;e49414.
Issue time：2020年

In this work, we investigated the microphase separation, mechanical, and

dynamic mechanical properties of thermoplastic polyurethane elastomers (TPUs)

with one-soft segment (polypropylene glycol, PPG, or hydroxyl-terminated polybutadiene,

HTPB) or bi-soft segment (PPG and HTPB) using FTIR, XRD, SAXS

and amplitude modulated-frequency modulated viscoelastic mode of AFM (AMFM

mode AFM) methods. The results showed that the microphase separation

process of hard and soft segments (HS and SS) in TPU containing PPG and HTPB

soft segments (PPG-HTPB-PU) was restricted by randomly alternated bi-soft segments,

which results in formation of a low content of irregular-shaped hard

domain (HD). In addition, the microphase separation of PPG-HTPB-PU induced

a triple-phased structure of HD, HTPB rich phase and mesophase. The mesophase

of PPG-HTPB-PU was formed of HS, PPG and HTPB segments which were

excluded out of HD and HPTB rich domains during microphase separation process.

The damping temperature range (at tan δ greater than 0.3) of PPG-HTPB-PU

was from ?14.6 to 32.1
C (46.5
C) which was more broad than that of TPU containing

HTPB soft segment (HTPB-PU). The broad damping temperature range of

PPG-HTPB-PU is mainly attributed to the enhanced energy consumption caused

by the frictional motions of mixed segments of mesophase.