Castor oil polyol (COP) having a hydroxyl number of 400 mg KOH/g was prepared through the transesterification reaction of castor oil with glycerol. The effect of reaction temperature on the composition, hydroxyl number and viscosity of the COP products was studied. A series of rigid polyurethane foams were synthesised using the mixtures comprising COP and a petroleum-based polyol with various proportions as polyol component. It was found that the foaming rate, compressive strength and dimensional stability and morphology of resulting foams were dominated by the foam formulation, in a more accurate way, COP content in the polyol mixtures. The combination of expandable graphite and dimethyl methyl phosphonate exhibited stronger flame retardant function which was ascribed to the synergistic effect associated with the simultaneous presence of the two additives. An improvement in thermal stability was observed due to the inclusion of the flame retardants.
TanS., AbrahamT. and FerenceD., MacoskoC.W: ‘Rigid polyurethane foams from a soybean oil-based Polyol’, Polymer, 2011, 52, 2840–2846. doi: 10.1016/j.polymer.2011.04.040
2.
SinghH., SharmaT. P. and JainA. K.: ‘Characterization of polyurethane foams from soybean oil’, J. Appl. Polym. Sci., 2002, 86, 3097–3107. doi: 10.1002/app.11322
3.
ThirumalM., KhastgirD., SinghaN. K., ManjunathB. S. and NaikY. P.: ‘Effect of foam density on the properties of water blown rigid polyurethane foam’, J. Appl. Polym. Sci., 2008, 108, 1810–1817. doi: 10.1002/app.27712
4.
SharmaV. and KunduP. P.: ‘Condensation polymers from natural oils’, Prog. Polym. Sci., 2008, 33, 1199–1215. doi: 10.1016/j.progpolymsci.2008.07.004
5.
PawlikH. and ProciakA.: ‘Influence of palm oil-based polyol on the properties of flexible polyurethane foams’, J. Polym. Environ., 2012, 20, 438–445. doi: 10.1007/s10924-011-0393-2
6.
FerrerM. C. C., BabbD. and RyanA. J.: ‘Characterisation of polyurethane networks based on vegetable derived polyol’, Polymer, 2008, 49, 3279–3287. doi: 10.1016/j.polymer.2008.05.017
7.
KaushikA. and SinghP.: ‘Kinetic study of polyurethane reaction between castor oil/TMP polyol and diphenyl methane diisocyanate in bulk’, Inter. J. Polym. Mater., 2006, 55, 549–561. doi: 10.1080/00914030500212248
8.
VeroneseV. B., MengerR. K., ForteM. C. and PetzholdC. L.: ‘Rigid polyurethane foam based on modified vegetable oil’, J. Appl. Polym. Sci., 2011, 120, 530–537. doi: 10.1002/app.33185
9.
ZatorskiW., BrzozowskiZ. K. and KolbreckiA.: ‘New developments in chemical modification of fire-safe rigid polyurethane foams’, Polym. Degrad. Stab., 2008, 93, 2071–2076. doi: 10.1016/j.polymdegradstab.2008.05.032
10.
ThirumalM., KhastgirD., NandoG. B., NaikY. P. and SinghaN. K.: ‘Halogen-free flame retardant PUF: Effect of melamine compounds on mechanical, thermal and flame retardant properties’, Polym. Degrad. Stab., 2010, 95, 1138–1145. doi: 10.1016/j.polymdegradstab.2010.01.035
11.
BianX-C., TangJ-H. and LiZ-M.: ‘Flame retardancy of hollow glass microsphere/rigid polyurethane foams in the presence of expandable graphite’, J. Appl. Polym. Sci., 2008, 109, 1935–1943. doi: 10.1002/app.27786
YeL., MengX-Y., LiuX-M., TangJ-H. and LiZ-M.: ‘Flame-retardant and mechanical properties of high-density rigid polyurethane foams filled with decabrominated diphenyl ethane and expandable graphite’, J. Appl. Polym. Sci., 2009, 111, 2372–2380. doi: 10.1002/app.29242
14.
YeL., MengX-Y., JiX., LiZ-M. and TangJ-H.: ‘Synthesis and characterization of expandable graphite–poly(methyl methacrylate) composite particles and their application to flame retardation of rigid polyurethane foams’, Polym. Degrad. Stab., 2009, 94, 971–979. doi: 10.1016/j.polymdegradstab.2009.03.016
15.
ShiL., LiZ-M., YangM-B. and YinB.: ‘Expandable graphite for halogen-free flame-retardant of high-density rigid polyurethane foams’, Polym.-Plast. Technol. Eng., 2005, 44, 1323–1337. doi: 10.1080/03602550500208145
16.
BianX-C., TangJ-H., LiZ-M., LuZ-Y. and LuA.: ‘Dependence of flame-retardant properties on density of expandable graphite filled rigid polyurethane foam’, J. Appl. Polym. Sci., 2007, 104, 3347–3355. doi: 10.1002/app.25933
17.
ZhangA., ZhangY., LvF. and ChuP. K.: ‘Synergistic effects of hydroxides and dimethyl methylphosphonate on rigid halogen-free and flame-retarding polyurethane foams’, J. Appl. Polym. Sci., 2013, 128, 347–353. doi: 10.1002/app.38200
18.
ModestiM. and LorenzettiA.: ‘Expandable graphite as an intumescent flame retardant in polyisocyanurate–polyurethane foams’, Polym. Degrad. Stab., 2002, 78, 167–173. doi: 10.1016/S0141-3910(02)00130-1
19.
XieR. and QuB.: ‘Synergistic effects of expandable graphite with some halogen-free flame retardants in polyolefin blends’, Polym. Degrad. Stab., 2001, 71, 375–380. doi: 10.1016/S0141-3910(00)00188-9
20.
ThirumalM., KhastgirD., SinghaN. K., ManjunathB. S. and NaikY. P.: ‘Effect of expandable graphite on the properties of intumescent flame-retardant polyurethane foam’, J. Appl. Polym. Sci., 2008, 110, 2586–2594. doi: 10.1002/app.28763
21.
KrevelenD. W.: ‘Some basic aspects of flame resistance of polymeric materials’, Polymer, 1975, 16, 615–620. doi: 10.1016/0032-3861(75)90157-3
22.
TangZ., Maroto-ValerM. M., AndrésenJ. M., MillerJ. W., ListemannM. L., McDanielP. L., MoritaD. K. and FurlanW. R.: ‘Thermal degradation behavior of rigid polyurethane foams prepared with different fire retardant concentrations and blowing agents’, Polymer, 2002, 43, 6471–6479. doi: 10.1016/S0032-3861(02)00602-X
