Morphology control of segmented polyurethanes by crystallization of hard and soft segments

Hood, Matthew A.; Wang, Bingbing; Sands, James M.; Scala, John J. La; Beyer, Frederick L.; Li, Christopher Y.

doi:10.1016/j.polymer.2010.03.027

Cited by 133 publications

(101 citation statements)

References 53 publications

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“…Figure 6 shows a typical example of SEM micrographs of segmented Bio-TPUs. As expected from literature data reported for different segmented polyurethanes [3,11,23,24], the TPUs developed in the present study exhibited a hetero-phase structure consisting of hard and soft domains. A NCO is the integrated absorbance for the isocyanate group, A CH 2 is the integrated absorbance for the CH 2 group and (A NCO /A CH 2 ) 0 is the relative absorbance extrapolated for time zero.…”

Section: Polymerization Kineticssupporting

confidence: 90%

“…Moreover, the amine peak at 3320 cm -1 appeared to be narrow and relatively symmetric, which normally suggests the absence of a significant number of free amines to be detected by FTIR. In fact, if the mixing phase was prevalent, a shoulder on the highfrequency side of the 3320 cm -1 band would appear, related to free amine, and the full-width at halfmaximum would be broad, which was not observed here [11][12][13]. Figure 3 shows the temperature rise profiles as a function of reaction process time for bio-based samples at different macrodiol/CE ratios and catalyst concentrations (0.02, and 0.04 vol% of total reaction mixture).…”

Section: Tensile Testingcontrasting

confidence: 50%

“…The extent and type of hydrogen bonding can be inferred by observing the intensities of the carbonyl 'shoulder' at 1714 cm -1 and of the PEG peak and its breadth at 1110 cm -1 . It was reported [11][12][13] that the carbonyl peak can be separated into three regions, related to different types of hydrogen bonding in segmented TPUs. Carbonyl not involved in hydrogen bonding has peaks observed near 1732 cm -1 , whereas carbonyl associated with poorly ordered hydrogen bonding was observed at 1714 cm -1 and well organized carbonyl, strongly hydrogen bonded to amines, was observed around 1685 cm -1 [11][12][13].…”

Section: Tensile Testingmentioning

confidence: 99%

“…Further, the T g of pure HS was found to be 102°C (Table 3). Recent results on HDI-BDO-PEG polyurethanes with high %HS content (> 45 wt% HS), obtained by one-shot polymerization in solution, indicated that it was impossible to observe glass transition for HS domains, at heating rates of 5 and 40°C/min [11]. This was ascribed to the relatively high degree of crystallization of HS domains, as indicated by the high T m values of their HS domains, as compared to pure HDI-BDO polymers, and to the small changes in heat capacity.…”

Section: Thermal Behaviormentioning

confidence: 99%

See 3 more Smart Citations

Development of bio-based thermoplastic polyurethanes formulations using corn-derived chain extender for reactive rotational molding

Rashmi¹,

Rusu²,

Prashantha³

et al. 2013

Express Polym. Lett.

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Abstract. Partly bio-based segmented thermoplastic polyurethane (TPU) formulations were developed to fulfill the requirements of the reactive rotational molding process. They were obtained by one-shot bulk polymerization between an aliphatic diisocyanate (1,6-hexamethylene diisocyanate), a polyether polyol as macrodiol (polyethylene glycol) and a biobased corn-derived 1,3-propanediol as chain extender (CE), in presence of a catalyst, at an initial temperature of 45°C. Equivalent TPU formulations with classical petroleum-based 1,3-propanediol were also prepared for a purpose of comparison. TPU with different soft to hard segment (SS/HS) ratios were synthesized by varying the macrodiol and CE concentrations in the formulations. For each formulation, the evolution of the reaction temperature as a function of time was monitored and the kinetics of polymerization was studied by Fourier Transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR). The morphology, thermal properties, solubility in different solvents and tensile properties of the final products were analyzed. All synthesized polyurethanes are 100% linear polymers and the extent of microphase separation, as well as the thermal and mechanical properties highly depends on the HS content, and glass transition temperature and Young modulus can be tuned by adjustment of the SS/HS ratio. All results indicate that petrochemical CE can be replaced by its recently available corn-derived homologue, without sacrificing any use properties of the final polyurethanes.

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Section: Polymerization Kineticssupporting

confidence: 90%

Section: Tensile Testingcontrasting

confidence: 50%

Section: Tensile Testingmentioning

confidence: 99%

Section: Thermal Behaviormentioning

confidence: 99%

See 2 more Smart Citations

Development of bio-based thermoplastic polyurethanes formulations using corn-derived chain extender for reactive rotational molding

Rashmi¹,

Rusu²,

Prashantha³

et al. 2013

Express Polym. Lett.

View full text Add to dashboard Cite

show abstract

“…Thermal stabilities of PU are very important properties which has attracted much attention in the literature over the past decades (Król et al 2010;Yeh et al 2010). Soft segment blocks usually have low glass transition temperature (T g ) and normally are polyether or polyester (Hood et al 2010;Wang et al 1983). Thermal stability of PU is usually up to 250°C and the hard segments of urethane linkages initiated decomposition (Tyagi et al 1984).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Thermal Properties of Poly(ethylene glycol)-polydimetylsiloxane Crosslinked Copolymers

Zainuddin

Othaman²,

Aqma

et al. 2018

JSM

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Linear segmented polyurethanes: I. A kinetics study

Polo

Spontón

Jaramillo

et al. 2017

J of Applied Polymer Sci

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This work investigates the two-step polymerization between methylene diphenyl diisocyanate (MDI), two different poly(tetramethylene oxide) macrodiols, and 1,4-butanediol (BD) as chain extender. At the end of the prepolymerization, the reaction mixture contains MDI in excess and a prepolymer with isocyanate end group. Then, BD and a solvent (tetrahydrofuran) were added to start the finishing stage under nominal stoichiometric equilibrium. The reaction was analyzed by Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance ( 1 H-NMR), and size exclusion chromatography. 1 H-NMR was employed to follow global concentrations of unreacted isocyanate end groups and internal urethane groups. This information enabled to estimate the following "effective" rate constants: k 1 5 1.07 3 10 23 L mol 21 s 21 for the prepolymerization; and k 2 5 1.94 3 10 24 L mol 21 s 21 for the finishing stage. These values are subject to errors caused by biases introduced in the recipe, in the measurements, in the reaction conditions, in the quality of reagents, and in the reaction mechanism assumptions. Such errors also explain the dispersion of the published rate constants values. The 1 H-NMR measurements also enabled to estimate the evolution (with extent of reaction) of the numberaverage number of structural units along the prepolymerization and finishing stages; and such estimates reasonably verify Flory's classical expressions.

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Morphology control of segmented polyurethanes by crystallization of hard and soft segments

Cited by 133 publications

References 53 publications

Development of bio-based thermoplastic polyurethanes formulations using corn-derived chain extender for reactive rotational molding

Development of bio-based thermoplastic polyurethanes formulations using corn-derived chain extender for reactive rotational molding

Synthesis and Thermal Properties of Poly(ethylene glycol)-polydimetylsiloxane Crosslinked Copolymers

Linear segmented polyurethanes: I. A kinetics study

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