Structure-property relationship and shape memory effect of polyurethane copolymer cross-linked with pentaerythritol

Cho, Tae Keun; Chong, Mi Hwa; Chun, Byoung Chul; Kim, Hye Ran; Chung, Yong‐Chan

doi:10.1007/bf02908153

Cited by 30 publications

(21 citation statements)

References 12 publications

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“…Study found that the dependence of the glass transition temperature on the density of crosslink was approximately linear [29]. The post-crosslinking reaction tended to further increase the glass transition temperature [30]. It was assumed that if the post-crosslinking reaction occurred as successfully as expected, the glass transition temperature of CPSU series would increase compared to those of RPSU series.…”

Section: Mechanical and Thermal Properties Of Rpsu And Cpsu Filmsmentioning

confidence: 97%

Study on reactive polydimethylsiloxane-modified waterborne polyurethanes

Zhang

Wu²,

et al. 2011

J Polym Res

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A series of novel reactive polydimethylsiloxanes (PDMS) bearing hydroxypropyl group at both chain ends and carbonyl groups at the side chain were incorporated with toluene 2,4-diisocyanate, dimethylol propionic acid and polypropylene glycol by the prepolymer process to synthesize a series of reactive PDMS-modified waterborne polyurethanes. After post-added dihydrazide, self-crosslinking was achieved by the reaction between the dihydrazide and carbonyl group during film formation. The latex film properties of them were investigated compared with that of pure waterborne polyurethane. Crosslinking was indeed enhanced in the films. Tensile strength, elongation at break and higher performance in water and solvent adsorptions were also detected.

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Section: Mechanical and Thermal Properties Of Rpsu And Cpsu Filmsmentioning

confidence: 97%

Study on reactive polydimethylsiloxane-modified waterborne polyurethanes

Zhang

Wu²,

et al. 2011

J Polym Res

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“…The SM effect in polymers originates from the existence of a thermally "reversible" phase transition, e.g., from glassy to rubbery state, and from distinct phase separation among hard and soft segments due to the incompatible nature of each segment [151]. As known from thermoplastic block copolymers like SMPUs, such interactions among hard segments, like hydrogen bonding, dipole-dipole and induced dipole-dipole interactions, have a significant impact on the phase separation of hard and soft segments, same as the ratio of crystalline to amorphous domains and presumably the size distribution of crystallites.…”

Section: Structure and Morphology As Functional Determinantsmentioning

confidence: 99%

“…Cho et al [151] took advantage of pentaerythritol as a four-way cross-linker for SMPU block copolymers. For the investigated (polytetramethylene glycol (PTMG)/4,4'-methylene bis(phenylisocyanate) (MDI))-based SMP, it was shown that the chemical cross-linking of hard segments through pentaerythritol, using different cross-linker contents of 2, 4 and 6 wt% at hard segment contents of 25 and 30 wt%, respectively, gives best SM properties at hard segment contents of 25 wt% and the highest cross-linker contents chosen.…”

Section: Structure and Morphology As Functional Determinantsmentioning

confidence: 99%

Review on the Functional Determinants and Durability of Shape Memory Polymers

Pretsch

2010

Polymers

112

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Shape memory polymers (SMP) belong to the class of stimuli-responsive materials and have generated significant research interest. Their capability to retain an imposed, temporary shape and to recover the initial, permanent shape upon exposure to an external stimulus depends on the "functional determinants", which in simplistic terms, can be divided into structural/morphological and processing/environmental factors. The primary aim of the first part of this review is to reflect the knowledge about these fundamental relationships. In a next step, recent advances in shape memory polymer composites are summarized. In contrast to earlier reviews, studies on the impairment of shape memory properties through various factors, such as aging, compression and hibernation, lubricants, UV light and thermo-mechanical cycling, are extensively reviewed. Apart from summarizing the state-of-the-art in SMP research, recent progress is commented.

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“…One solution to this problem that has been investigated involves cross-linking the SMPU. [11][12][13][14] The crosslinked structure demonstrated higher tensile stress and maintained high shape recovery during cyclic tests, but strain decreased substantially after crosslinking. A different crosslinking method in which SMPU chains were connected by a flexible poly(ethylene glycol) (PEG) was effective in attaining high tensile stress and strain capability, and reliable high-fidelity shape recovery under severe conditions.…”

Section: Introductionmentioning

confidence: 99%

Grafting of shape memory polyurethane with poly(ethyleneimine) and the effect on electrolytic attraction in aqueous solution and shape recovery properties

et al. 2011

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Shape memory polyurethane (SMPU) grafted using polyethyleneimine (PEI) was tested for its electrolytic attraction in aqueous solution and shape memory effect. The PEI was connected through a second 4,4'-diphenylmethane diisocyanate anchored to the carbamate moiety of SMPU. Two series of SMPU that differed in soft segment polytetramethylene glycol and PEI content were prepared to compare their tensile and shape memory properties. Shape recovery was high as 99% and reduced only to 97% after four test cycles. The PEI group attached to the SMPU chain, if converted to the imminium salt form, was designed to work as an electrolyte during water electrolysis and was to be attracted toward the cathode to show SMPU movement in aqueous solution. The electrolytic attraction of SMPU in aqueous solution was demonstrated in an experiment in which a specimen moved to the cathode only when voltage above a minimum was applied. The mechanism and application of this finding are discussed.

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Structure-property relationship and shape memory effect of polyurethane copolymer cross-linked with pentaerythritol

Cited by 30 publications

References 12 publications

Study on reactive polydimethylsiloxane-modified waterborne polyurethanes

Study on reactive polydimethylsiloxane-modified waterborne polyurethanes

Review on the Functional Determinants and Durability of Shape Memory Polymers

Grafting of shape memory polyurethane with poly(ethyleneimine) and the effect on electrolytic attraction in aqueous solution and shape recovery properties

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