Mechanical properties and fractography of block copolymers based on NR and MDI-based polyurethanes

Nair, Maya Narayanan; Sukumar, Prema; Jayashree, V.; Nair, M. R. Gopinathan

doi:10.1007/s00289-010-0251-8

Cited by 8 publications

(2 citation statements)

References 18 publications

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“…Lignin-containing PU-COs presented a smooth transition from a ductile fracture (smooth grooves, white arrows) to a brittle one (sharp surfaces, black arrows) [38] near the TKL concentration value of 30 wt%, as illustrate in Figure 9a and 9b; for the PU-MCO1, there is a change in fracture mechanism at 20 wt% TKL content (Figure 9c and 9d). This behavior is similar for PU-MCO2, where the value is 10 wt% lignin content (Figure 9e and 9f).…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 91%

Bio-based polyurethane prepared from Kraft lignin and modified castor oil

Tavares¹,

Boas²,

Schleder³

et al. 2016

Express Polym. Lett.

118

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Abstract. Current challenges highlight the need for polymer research using renewable natural sources as a substitute for petroleum-based polymers. The use of polyols obtained from renewable sources combined with the reuse of industrial residues such as lignin is an important agent in this process. Different compositions of polyurethane-type materials were prepared by combining technical Kraft lignin (TKL) with castor oil (CO) or modified castor oil (MCO1 and MCO2) to increase their reactivity towards diphenylmethane diisocyanate (MDI). The results indicate that lignin increases the glass transition temperature, the crosslinking density and improves the ultimate stress especially for those prepared from MCO2 and 30% lignin content from 8.2 MPa (lignin free) to 23.5 MPa. Scanning electron microscopy (SEM) micrographs of rupture surface after uniaxial tensile tests show ductile-to-brittle transition. The results show the possibility to develop polyurethane-type materials, varying technical grade Kraft lignin content, which cover a wide range of mechanical properties (from large elastic/low Young modulus to brittle/high Young modulus polyurethanes).

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Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 91%

Bio-based polyurethane prepared from Kraft lignin and modified castor oil

Tavares¹,

Boas²,

Schleder³

et al. 2016

Express Polym. Lett.

118

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“…A wide range of polyurethane adhesives can be produced by changing the urethane content and the other building blocks presented in its formulation [2][3][4][5][6][7][8]. The building blocks of the polyurethane adhesives are mainly based on the polyisocyanates and polyols with 2-3 reacting groups per molecule.…”

mentioning

confidence: 99%

An evaluation of the mechanical and adhesion properties of a hydroxyl-terminated polybutadiene (HTPB)-based adhesive including different kinds of chain extenders

2015

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The effects of 1,5-pentanediol (PDO) and N, N-Bis (hydroxyethyl) aniline (ISL) chain extenders on the mechanical and adhesion properties of the polyurethane adhesives based on hydroxyl-terminated polybutadiene were studied. Results showed that both chain extenders (ISL and PDO) improved the adhesion properties of the polyurethane on the aluminum substrate. The peel test modulus increased significantly in the presence of both chain extenders. The increase was more pronounced using PDO chain extender (the one with aromatic side group). A decrease in contact angle and an increase in work of adhesion were obtained by addition of chain extenders to the polyurethane. The glass transition temperature of the PU did not change significantly in the presence of chain extenders. However, the cross-linking density and toughness of the polyurethane increased significantly by addition of the chain extenders. Results showed that chain extender without side chain (PDO) improved the adhesion as well as the mechanical properties of the polyurethane much greater than the one with aromatic side ring.

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Effect of the diisocyanate structure and the molecular weight of diols on bio‐based polyurethanes

Panwiriyarat

Tanrattanakul

Pilard

et al. 2013

J of Applied Polymer Sci

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Bio‐based polyurethanes (PU) containing poly(ε‐caprolactone) diol (PCL) and hydroxyl telechelic natural rubber (HTNR) were synthesized. The effect of the diisocyanate structure and the molecular weights of diols on the mechanical properties of PU were investigated. Three different molecular structures of diisocyanate were employed: an aliphatic diisocyanate (hexamethylene diisocyanate, HDI), an aromatic diisocyanate (toluene‐2,4‐diisocyanate, TDI) and a cycloalkane diisocyanate (isophorone diisocyanate, IPDI). Two molecular weights of each diol were selected. When HDI was employed, a crystalline PU was generated while asymmetrical structures of TDI and IPDI provided an amorphous PU. The presence of crystalline domains was responsible of a change in tensile behavior and physical properties. PU containing TDI and IPDI showed a rubber‐like behavior: low Young's modulus and high elongation at break. The crystalline domains in PU containing HDI acted as physical crosslinks, enhancing the Young's modulus and reducing the elongation at break, and they are responsible of the plastic yielding. The crystallinity increased the tear strength, the hardness and the thermal stability of PU. There was no significant difference between the TDI and IPDI on the mechanical properties and the physical characteristics. Higher molecular weight of PCL diol changed tensile behavior from the rubber‐like materials to the plastic yielding. Thermal and dynamic mechanical properties were determined by using DSC, TGA and DMTA. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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Mechanical properties and fractography of block copolymers based on NR and MDI-based polyurethanes

Cited by 8 publications

References 18 publications

Bio-based polyurethane prepared from Kraft lignin and modified castor oil

Bio-based polyurethane prepared from Kraft lignin and modified castor oil

An evaluation of the mechanical and adhesion properties of a hydroxyl-terminated polybutadiene (HTPB)-based adhesive including different kinds of chain extenders

Effect of the diisocyanate structure and the molecular weight of diols on bio‐based polyurethanes

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