IR Spectroscopic Studies of Urethane Foam Formation

Merten, Rudolf; Lauerer, D.; Dahm, Manfred

doi:10.1177/0021955x6800400704

Cited by 23 publications

(8 citation statements)

References 10 publications

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“…), and these results are in quantitative agreement with those of Harthcock and co‐workers , where the residual isocyanate content is reduced to 8%. The NCO band originally present at 2270 cm −1 has almost disappeared; this analogous reaction sequence provides direct comparison with previously published results .…”

Section: Resultssupporting

confidence: 87%

Determination of Polyurethane Foam Growth Kinetics by a Simple Column Height Test

Saavedra¹,

Gracia-Fadrique²

2015

Int. J. Chem. Kinet.

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In the present work, the height of foam column has been used to monitor the reaction of the isocyanate group. Kinetic modeling describes the conversion versus time curves. The global reaction can be divided into two different paths: the blowing reaction and the polymerization. The kinetics of the reaction of toluene diisocyanate with a polypropylene glycol has been studied with auxiliary blowing agents; the concentration of NCO and OH groups could be considered equivalent during all the experiments as a model for similar polyurethane systems. Despite the complexity of the system in which different kinetic orders are possible, as well a physically controlled diffusion process, data were fitted to a simple kinetic model of an apparent order. The results obtained have enabled us to propose a reaction path and catalyzed second‐order kinetic model.

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Section: Resultssupporting

confidence: 87%

Determination of Polyurethane Foam Growth Kinetics by a Simple Column Height Test

Saavedra¹,

Gracia-Fadrique²

2015

Int. J. Chem. Kinet.

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“…However, a number of discrepancies in the literature redirected our attention to this class of compounds, whose importance in the chemistry of polyurethanes is so great. For instance, Merten et al [1][2][3] found no absorption at 1640 cm-' in the infrared spectrum of a polyurethane foam produced with the aid of water and attributed this to a secondary reaction of the polyurea with isocyanate to form the biuret. An attempt, using model compounds and analogous conditions, to reproduce such a secondary reaction to form the biuret was, however, unsuccessful.…”

Section: Introductionmentioning

confidence: 99%

Structural investigation of polyurethanes: Infrared spectroscopic investigations of monomeric and polymeric N,N′-diaryl ureas

Hocker

1980

J. Appl. Polym. Sci.

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The carbonyl stretching vibration of crystalline N,N′‐diaryl ureas at 1640 cm−1 undergoes a very considerable shift to 1700 cm−1 when these compounds are in solution. This finding is of particular significance in connection with the hard segments of polyurethane elastomers. The absence of a carbonyl band at 1640 cm−1 in polyurethane–polyurea systems does not indicate the absence of urea groups or the reaction of urea groups to biuret groups. Urea groups may instead be present in the dissolved, i.e., noncrystalline, form. On the other hand, the absorption at 1640 cm−1 is suitable for the determination of crystallization kinetics.

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“…The polyether grafts contain inner PEO blocks and PPO end blocks. The PPO block comprises from 50 to 70 percent of the polyether blocks (1,5,20,21). …”

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confidence: 99%

Morphology of water‐blown flexible polyurethane foams

Armistead

Wilkes

Turner

1988

J of Applied Polymer Sci

121

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Committee Chairman: Garth L. Wilkes Chemical Engineering (ABSTRACT)A series of four water-blown flexible polyurethane foams was produced in which the water content was varied from 2 to 5 pph at a constant isocyanate index of 110.A portion of each foam was thermally compression molded into a plaque. The morphology of the foams and plaques was investigated using OMS, DSC, FTI R, TEM, SEM, swelling, WAXS, and SAXS. A high degree of phase separation occurs in these foams and the degree of phase separation is independent of water (ha rd segment) content. In the foam with the lowest water content the morphology is similar to that of typical segmented urethane elastomers. Small hard segment domains are present with a correlation distance of roughly 7. 0 nanometers. When the water content is increased a binodal distribution of hard segments appears.There are the smal I ha rd segment domains typical of segmented urethane elastomers as well as large hard segment aggregates greater than 100 nanometers 1n diameter. The large domains are thought to be aggregates of polyurea that precipitated during the manufacture of the foam. The foam making process successfully incorporated the trifunctional polyols into a network indicating a high degree of polymerization for the hydroxyl-isocyanate reaction. Unreacted isocyanate is present in the foams a month after curing. It is believed to be trapped in the large urea aggregates.WAXS patterns of the foams suggest hard segment ordering that may be of a paracrystalline nature but certainly lacking in true crystallinity. ACKNOWLEDGEMENTSI would like to thank my major professor Dr. Wilkes for his patience, concern, and support, without which I probably would not have remained in Blacksburg to complete this work.I wou Id also Ii ke to thank Dr. Glasser and Dr. Sebba for the interest they showed in my work and the time and effort they spent reviewing my thesis.I would like to thank Rick Allen and Dr. Lin for their assistance in using the ORNL facilities and Dinesh Tyagi and Brandt Carter for many helpful discussions.Finally, I would like to thank all of the group members for their everyday greetings, smiles, and conversion. In particular I would like to thank Dinesh and Ruby, Brandt, Marty and Martha, andBruce.iv One reason for this is that in the production of polyurethane foams, the blowing and gelling reactions occur simultaneously. Any change in chemistry or processing conditions alters both the cell structure and the morphology of the material comprising the cell structure. As a result, there is no way to evaluate the material independent of cell structure or cell structure independent of material. Changes in chemical and processing variables have been extensively studied as to their influence on bulk properties of the foam and polyurethane foams with a wide range of physical properties can be produced ( 1-5).This 'technological' approach to the development of polyurethane foams has been very successful and presently, the yearly production of polyurethane foams far outweighs other types...

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IR Spectroscopic Studies of Urethane Foam Formation

Cited by 23 publications

References 10 publications

Determination of Polyurethane Foam Growth Kinetics by a Simple Column Height Test

Determination of Polyurethane Foam Growth Kinetics by a Simple Column Height Test

Structural investigation of polyurethanes: Infrared spectroscopic investigations of monomeric and polymeric N,N′-diaryl ureas

Morphology of water‐blown flexible polyurethane foams

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