Effects of aggregation structure on rheological properties of thermoplastic polyurethanes

Yamasaki, Satoshi; Nishiguchi, Daisuke; Kojio, Ken; Furukawa, Mutsuhisa

doi:10.1016/j.polymer.2007.06.006

Cited by 59 publications

(36 citation statements)

References 31 publications

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“…A incompatibilidade termodinâmica dos segmentos ocasiona a separação de microfases [3] devido à maior temperatura de fusão dos segmentos rígidos que os tornam incompatíveis com os macios. Os segmentos rígidos têm um papel importante dentro dos domínios cristalinos por permitirem pontes de hidrogênio entre os grupos uretanos e os carboxílicos.…”

Section: Introductionunclassified

Efeito da incorporação de talco nas características térmicas, mecânicas e dinâmico-mecânicas de poliuretanos termoplásticos

et al. 2011

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RESUMOO objetivo deste trabalho foi investigar o efeito da adição de talco, um agente nucleante amplamente empregado em formulações de termoplásticos em geral, no comportamento de cristalização e nas propriedades mecânicas de dois poliuretanos termoplásticos (TPUs) de diferentes massas molares. Foram realizadas análises de calorimetria exploratória diferencial (DSC), termogravimetria (TGA), dinâmico-mecânica (DMA), além de ensaios mecânicos. Observou-se que a adição de talco aumentou a temperatura de cristalização e a de decomposição média do TPU de maior massa molar média, no entanto, não foi observada mudança para concentrações superiores a 0,5% (m/m). Análises de DMA indicaram um aumento do módulo de armazenamento com a aditivação somente para o TPU de maior massa molar média. Nos ensaios mecânicos, não foi possível observar alterações significativas nas propriedades. O estudo realizado demonstrou a importância do conhecimento do efeito da adição de talco como agente nucleante em compostos de TPU, visando o melhoramento do desempenho destes materiais. Palavras -chave:Talco, poliuretano termoplástico, agente nucleante, cristalização.The effect of talc addition on the thermal, mechanical and dynamicmechanical characteristics of thermoplastic polyurethanes ABSTRACTThe aim of this work was to investigate the effect of adding talc, a nucleating agent widely used in general purpose thermoplastic formulations, on the crystallization behavior and the mechanical properties of two thermoplastic polyurethanes (TPUs) of different molecular weight. In this study, differential scanning calorimetry (DSC), thermogravimetry (TGA), dynamic-mechanical analysis (DMTA) and mechanical tests were employed. It was observed that the addition of talc increased the crystallization and the decomposition temperature of the highest average molecular weight TPU, although no change was observed at concentrations above 0.5 wt%. DMA analyses showed an increase in storage modulus only for the TPU with the highest average molecular weight. Mechanical testing did not show significant changes in the evaluated properties. The study demonstrated the importance of knowing the particular effects of adding talc as a nucleating agent in TPU compounds, aimed at improving their performance.Keywords: Talc, thermoplastic polyurethane, nucleating agent, crystallization. INTRODUÇÃOA necessidade de se produzir materiais com menor custo e maior disponibilidade no mercado tornou-se um dos grandes desafios para a indústria de componentes para calçados. No setor de laminados, por exemplo, é de grande importância o desenvolvimento de materiais com boas propriedades adesivas que aliem baixa temperatura de processamento e curto tempo de cristalização.O poliéster à base de caprolactona (PES) apresenta custo relativamente elevado e baixa disponibilidade no mercado, sendo prioritariamente utilizado para aplicações mais atraentes economicamente, como na área médica. Por estes motivos, é crescente o interesse em substituir o PES,

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Section: Introductionunclassified

Efeito da incorporação de talco nas características térmicas, mecânicas e dinâmico-mecânicas de poliuretanos termoplásticos

et al. 2011

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“…To form the microphaseseparated structure in polymers, they need to possess block structures, which are chemically connected each other. It is well-known that the polyurethane elastomers (PUEs), which possess the multiblock structure, show the microphase-separated structure, [1][2][3][4][5][6] resulting in giving some unique properties, such as mechanical and adhesive properties [6][7][8][9][10][11][12][13][14][15][16] and biocompatibility. 17 To functionalize the PUs with the microphase-separated structure, one needs to control the structures precisely.…”

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confidence: 99%

“…There has been reported some factors to control the microphaseseparated structure. A polymerization method, 13 thermal treatment 3,14 and chemical structures of raw materials including molecular weight [6][7][8][9][10][11][12]15,16 can be given as examples. First, by changing the polymerization method, one can control the primary structure of the PUs.…”

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confidence: 99%

“…Second, thermal treatment usually progresses the degree of microphase separation. 3,14 For instance, when the PUs are annealed at a certain temperature, the hard segment domains with melting point above the annealing temperature would be progressed. Finally, by annealing a proper temperature, the microphaseseparated structure is closed to the equilibrium state.…”

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The Microphase-separated Structure of Polyurethane Bulk and Thin Films

et al. 2009

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The microphase-separated structure of polyurethane bulk and thin films were investigated using atomic force microscopy (AFM). The polyurethane (PUs) were synthesized with poly(oxytetramethylene) glycol (PTMG), 4,4 0 -diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD) by a prepolymer method. The hard segment contents were 34 and 45 wt %. Polarized optical microscopy (POM) revealed that the 34 wt % PUE is homogeneous at a macroscopic level, while the 45 wt % one is macrophase-separated into two phases. One phase forms spherulites of ca. 2-5 mm in diameter. AFM observation for the 34 wt % PUE showed the microphase-separated structure, consisting of hard segment domains and a soft segment matrix. In contrast, for the 45 wt % PUE, a lot of the hard segment domains were observed in the spherulite region, indicating that spherulites include much amount of hard segment component, in contrast, outside of spherulite exhibited similar structure to that of 34 wt % one. For the PU bulk, the different microphase-separated structure in the inside and outside of spherulite was successfully observed for the first time. Also, the microphase-separated structure of PU films was investigated as a function of the film thickness. The PU films exhibited similar microphase-separated structure. For the thicker film ($200 nm), the interdomain spacing almost corresponded to bulk one. On the other hand, that for the film thickness below 7 nm dramatically decreased. This seems to be simply related to a decreasing space. We obtained the experimental data, which the phase-separated domain size of multiblock copolymer decreased with decreasing film thickness.KEY WORDS: Polyurethane / Microphase-separated Structure / Atomic Force Microscopy / Thin Film / A microphase-separated structure formed in polymers plays a quite important role for their properties, such as electric, adsorption, mechanical properties. To form the microphaseseparated structure in polymers, they need to possess block structures, which are chemically connected each other. It is well-known that the polyurethane elastomers (PUEs), which possess the multiblock structure, show the microphase-separated structure, 1-6 resulting in giving some unique properties, such as mechanical and adhesive properties [6][7][8][9][10][11][12][13][14][15][16] and biocompatibility.17

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“…For the light stable applications, aliphatic diisocyanates, such as dicyclohexyl methane -4, 4′-diisocyanate (H 12 MDI) 4) , isophorone diisocyanate (IPDI) 5) , hexamethylene diisocyanate (HDI) 6) , 2,5(2,6)-bis(isocyanatomethyl)bicyclo [2.2.1] heptane (NBDI TM ) 6) and 1,3-bis (isocyanatemethyle) cyclo-expected that 1,4-H 6 XDI is applicable to various polyurethane products such as thermoplastic polyurethane elastomer (TPU) 8,9,10,11,18) , thermosetting polyurethane elastomer (TSU) 8,9,[12][13][14] , polyurethane solution 8,15) , polyisocyanate hardener 16) , polyurethane dispersion (PUD) 15,17) and flexible polyurethane foam 8,18) . This paper will report superior properties of polyurethane elastomers based on 1,4-H 6 XDI, in particular, mechanical and thermal properties using rheological technique.…”

Section: Introductionmentioning

confidence: 99%

High Performance Polyurethane Elastomers Using New Cyclaliphatic Diisocyanate

Yamasaki

Kuwamura

Morita

et al. 2017

J. Soc. Rheol., Jpn

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Trans-1,4-bis (isocyanatomethyl) cyclohexane (1,4-H 6 XDI) has been newly developed as a novel cycloaliphatic diisocyanate with a high symmetric chemical structure. The PUEs were prepared with 1,4-H 6 XDI, polyesterpolyol as a long chain polyol and 1,4-butanediol (BD) as a chain extender. As the representative aromatic and aliphatic diisocyanates, 4,4′-diphenylmethane diisocyanate (MDI) and dicyclohexyl methane-4,4′-diisocyanate (H 12 MDI) were also used as the control. As a result, it was revealed that 1,4-H 6 XDI-based PUEs achieved high elasticity such as higher impact resilience, lower compression set, improved heat resistant, and good light stability which was not able to be realized with the existing diisocyanates. The reason is explained that the hard segment chains of the 1,4-H 6 XDI-based PUEs crystallized well with formation of hydrogen bonds in the PUEs due to the symmetric structure of 1,4-H 6 XDI. Thus, the 1,4-H 6 XDI-based PUEs can provide superior properties such as mechanical and thermal properties and excellent light stability compared to existing diisocyanate-based PUEs by rheological evaluation.

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Effects of aggregation structure on rheological properties of thermoplastic polyurethanes

Cited by 59 publications

References 31 publications

Efeito da incorporação de talco nas características térmicas, mecânicas e dinâmico-mecânicas de poliuretanos termoplásticos

Efeito da incorporação de talco nas características térmicas, mecânicas e dinâmico-mecânicas de poliuretanos termoplásticos

The Microphase-separated Structure of Polyurethane Bulk and Thin Films

High Performance Polyurethane Elastomers Using New Cyclaliphatic Diisocyanate

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