Superior Properties of Polyurethane Elastomers Synthesized with Aliphatic Diisocyanate Bearing a Symmetric Structure

Nozaki, Shuhei; Masuda, S.; Kamitani, Kazutaka; Kojio, Ken; Takahara, Atsushi; Kuwamura, Goro; Hasegawa, Daisuke; Moorthi, Krzysztof; Mita, Kazuki; Yamasaki, Satoshi

doi:10.1021/acs.macromol.6b02044

Cited by 72 publications

(63 citation statements)

References 33 publications

(49 reference statements)

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“…The majority of isocyanates used such as toluene-2,4-diisocyanate, isophorone diisocyanate, and 4,4-methylene diphenyl diisocyanate are aromatic in structure while aliphatic isocyanates, such as hexamethylene diisocyanate (HMDI), are also used (Teo et al, 1997, Chan-Chan et al, 2010, Prisacariu, 2011, Chung and Washburn, 2012, Zhang et al, 2015. Polyols are usually the more flexible of the two components which allows the formation of flexible PU materials and usually consist of polyesters, polyethers, or glycols such as polyethylene glycol (PEG), 1,4-butanediol, and polypropylene glycol (PPG) (Grassie and Zulfiqar, 1978;Wen et al, 2001;Oprea, 2010;Nozaki et al, 2017). The structure of these compounds is presented in Figure 2.…”

Section: Polyurethane (Pu)mentioning

confidence: 99%

The Effect of Plant Source on the Properties of Lignin-Based Polyurethanes

2018

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This work increases our understanding of the effect of plant source on the mechanical and morphological properties of lignin-based polyurethanes (PUs). Lignin is a polymer that is synthesized inside the plant cell wall and can be used as a polyol to synthesize PUs. The specific aromatic structure of the lignin is heavily reliant on the plant source from which it is extracted. These results show that the mechanical properties of ligninbased PUs differ based on lignin's plant source. The morphology of lignin-based PUs was examined using atomic force microscopy and scanning electron microscopy and the mechanical properties of lignin-based PU samples were measured using dynamic mechanical analysis and shore hardness (Type A). The thermal analysis and morphology studies demonstrate that all PUs prepared form a multiphase morphology. In these PUs, better mixing was observed in the wheat straw lignin PU samples leading to higher moduli than in the hardwood lignin and softwood lignin PUs whose morphology was dominated by larger aggregates. Independent of the type of the lignin used, increasing the fraction of lignin increased the rigidity of PU. Among the different types of lignin studied, PU with wheat straw soda lignin exhibited storage moduli ~2-fold higher than those of PUs incorporating other lignins. This study also showed that during synthesis all hydroxyl groups in the lignin are not available to react with isocyanates, which alters the number of cross-links formed within the PU and impacts the mechanical properties of the material.

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Section: Polyurethane (Pu)mentioning

confidence: 99%

The Effect of Plant Source on the Properties of Lignin-Based Polyurethanes

2018

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“…However, an excessive content of urethane in the product may reduce its flexibility, and thus the tensile strength and the elongation at break decrease. Previous studies have also reported that the elasticity, toughness, and other physical properties of PU materials are determined largely by the degree of phase separation and the interconnectivity of the hard segment, namely hard segment cohesion, as well as by the nature of the segment interface and the mixing of the hard segment in the soft segment (37,38). Moreover, according to a previous study (29), more linear shrinkage gaps can be buffered by PUDMA 3:1 when the same thickness of the PU layer is applied.…”

Section: Discussionmentioning

confidence: 99%

Synthesis, characterization, and aging resistance of the polyurethane dimethacrylate layer for dental restorations

Guo

Cheng

Wang

et al. 2020

European J Oral Sciences

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In this study, polyurethane dimethacrylate (PUDMA) was synthetized from different components and incorporated into a direct resin composite restoration system with the aim to buffer tooth–resin interfacial stresses and maintain the marginal adaptation. The tensile strength, elongation at fracture (ε), and thermal stability of the PUDMA layer were characterized, showing a tensile strength of 22 MPa, an ε of 112%, and a thermal decomposition temperature of about 282°C. In addition, the degree of conversion, water sorption/solubility, hydrophobicity, microtensile bond strength (μTBS), marginal leakage, and cytotoxicity in vitro were evaluated for the PUDMA layer. The data were analyzed using one‐way ANOVA, except for leakage depths (which were analyzed using the Wilcoxon paired‐rank test). The level of significance was set at 0.05. Compared with dental adhesives, PUDMA displayed a higher degree of conversion, lower water sorption/solubility, and improved hydrophobicity and biocompatibility in vitro. After thermocycling, the μTBS of the restoration system containing PUDMA had increased compared with the μTBS at 24 h. Restorations containing PUDMA showed lower leakage depths than those which did not contain PUDMA. In conclusion, because of its hydrophobic and elastic nature, the PUDMA layer, when used as an intermediate between tooth and resin restoratives, may buffer interfacial stresses, improve the stability and durability of the bonding interface, and reduce microleakage.

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“…The intensity of crystalline peak of bisFc-PU was much higher than that of monoFc-PU, presumably due to larger cohesive force of bisferrocene and the formation of wellorganized crystallized hard segment domains. 36 Therefore, it is reasonable to prove the existence of the crystalline phase. Fig.…”

Section: Morphologymentioning

confidence: 99%

Tuning chain extender structure to prepare high-performance thermoplastic polyurethane elastomers

Wang

Zhang

et al. 2018

RSC Adv.

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In this work, a novel strategy is developed to solve the issue of mutually exclusive high mechanical robustness and thermo-stability for thermoplastic polyurethane (PU). A leaf-like and reticulate interfingering superstructure can be seen. The superstructure of polyurethanes can also be tuned by the polarity of chain extender molecular via changing the number for ferrocene redox centres, thus to further enhance the thermal stability and elasticity of PUs. As a result, by incorporating bisferrocene units into the main chain of PU, a high-performance PU elastomer can be synthesized with a highest initial degradation temperature of T 5% of 345 C, a highest tensile strength of 42.3 MPa with an elongation over 1000%, as well as a toughness of 19.6 GJ m À3. These results conclusively suggest that high-performance thermoplastic polyurethane elastomers had great promise for potential application in a wide range of practical fields.

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Superior Properties of Polyurethane Elastomers Synthesized with Aliphatic Diisocyanate Bearing a Symmetric Structure

Cited by 72 publications

References 33 publications

The Effect of Plant Source on the Properties of Lignin-Based Polyurethanes

The Effect of Plant Source on the Properties of Lignin-Based Polyurethanes

Synthesis, characterization, and aging resistance of the polyurethane dimethacrylate layer for dental restorations

Tuning chain extender structure to prepare high-performance thermoplastic polyurethane elastomers

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