Rheological investigation of microphase separation transition of polyurethane elastomer

Hydroxyl-terminated hyperbranched polyurethane elastomer (HBPU) was synthesized by graft copolymerization of hyperbranched poly (amine-ester) polyols(HPAE) and polyether-based aliphatic polyurethane prepolymer(PPU), and the PPU was synthesized by step polymerization of isophorone diisocyanate(IPDI) with polyethylene glycol(PEG) and dibutyltin dilaurate(DBTDL) as catalyst. The FT-IR spectroscopy, TGA and XRD were used to characterize the structure, thermal properties and crystallinity of HBPU. The mechanical properties of the elastomers were conducted on a testing machine. Microphase separation of HBPU film surface was studied by atomic force microscopy (AFM). The experimental results showed that the HBPU took on excellent hydrogen bonding and mechanical properties. The tensile strength of HBPU elastomer reached to 20.6MPa, which increased by 41.2 times than that of PPU elastomer. And the elongation at break was as high as 251.3%.

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The Influential Factors of Property on Polyether-Polyol Type Polyurethane Elastomer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.704.289 ◽

2013 ◽

Vol 704 ◽

pp. 289-293 ◽

Cited By ~ 3

Author(s):

Fu Chun Xie ◽

Fu Quan Guo

Keyword(s):

Mechanical Properties ◽

Molecular Weight ◽

Hard Segment ◽

Microphase Separation ◽

Chain Extender ◽

Influential Factors ◽

Polyurethane Elastomer ◽

Elongation At Break ◽

Polyether Polyol ◽

Tear Resistance

Polyurethane (PU) elastomers based on all kinds of polyether-polygol, diisocyanate and chain extender were prepared by two-step processes;the different influential factors of polyurethane elastomer were discussed in detail. The results showed that when the molecular weight of polyether-polygol increased, the hardnesstensile strength and tear resistance of polyurethane elastomer decreased, but the elongation at break increased;the property of polyurethane elastomer increased with the increasing perecentage of hard segment phase;R numerical value (-NCO/-OH) was controlled between 1.01 and 1.03;the shorter chain-extender had excellent microphase separation and mechanical properties;With the amount of 1, 4-butadiene alcohol (BDO) incrasing, the performance of polyurethane elastomer becomes well,but when the amount of 1, 4-butadiene alcohol comes to a point it appears reverse.

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Morphological studies of linear (AB)n multiblock copolymers and their blends

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122320 ◽

1992 ◽

Vol 50 (1) ◽

pp. 384-385

Author(s):

Richard J. Spontak ◽

Steven D. Smith ◽

Arman Ashraf

Keyword(s):

Electron Microscopy ◽

Microphase Separation ◽

Multiblock Copolymers ◽

First Order ◽

Morphological Studies ◽

Transmission Electron ◽

First Order Phase Transition ◽

Covalently Bonded ◽

Total Molecular Weight ◽

First Order Phase

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.

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