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Please use this identifier to cite or link to this item:
http://hdl.handle.net/123456789/483
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| Title: | Reactivity of Raw Materials and Their Effects on Structure and Properties of Rigid Polyurethane Foams |
| Authors: | Singh, Harpal
Sharma, T P
Jain, A K |
| Keywords: | Blending
Blowing agents
Morphology
Polyurethanes
Pyrolysis
2007 |
| Issue Date: | 19-Oct-2011 |
| Abstract: | Formulations for rigid polyurethane foams
(RPUFs) based on crude 4,40-diphenylmethane diisocyanate,
polyether polyol, triethylenediamine, 1,4-butane diol,
poly(siloxane ether), methylene chloride, and water were
studied. The stoichiometric ratios of various foam ingredients
and their effects on physical properties such as the
cream time, gel time, tack-free time, and density of the
RPUF samples were studied. The results indicated that the
rate of RPUF formation increased with the catalyst (triethylenediamine
and tin) and water content. The density of the
RPUF samples blown with water, methylene chloride, and
a mixture of water and methylene chloride decreased from
240.1 to 33.4 kg/m3 with an increase in the blowing agent
contents. However, the RPUF density increased with
increasing contents of 1,4-butane diol. The cell morphology
and thermal properties of the RPUF samples were investigated
with scanning electron microscopy, thermogravimetric
analysis, derivative thermogravimetry, and differential
thermal analysis. Scanning electron microscopy results
revealed an average increase in the cell size of the RPUF
samples from 162 to 278 mm with increased water content.
A thermal behavior study indicated that the RPUF samples
decomposed in nitrogen and degraded in air through two
and three weight-loss stages, respectively. Foam pyrolysis
in nitrogen and combustion in air led to 15 and 0% char
residue, respectively. The results indicated that the thermal
stability of the RPUFs was better in nitrogen than in an air
atmosphere. 2007 Wiley Periodicals, Inc. J Appl Polym Sci
106: 1014–1023, 2007 |
| Description: | Journal of Applied Polymer Science, Vol. 106, No. 2, pp. 1014-1023, 2007. |
| URI: | http://hdl.handle.net/123456789/483 |
| Appears in Collections: | Published Articles
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