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Flame-Resistant Cellulose Fibers with Magnesium Hydroxide Prepared by Wet Electrospinning
Yingying ZhengVisiting Scholar
Department of Chemistry and Chemical Biology Rensselaer Polytechnic Institute, Troy, NY, USA
2013 Rensselaer Nanotechnology Center Research SymposiumWednesday, November 6, 2013
Robert J. Linhardt, Trevor J. Simmons, Jianjun Miao
Cellulose Fiber
Ease of thermal degradation, ignition and burning
Availability in vast quantitiesGood mechanical propertiesBiodegradabilityHydrophilicity…
Commonly Used Durable Flame Retardants
PEPBP
Halogen, Nitrogen, Organic-phosphorus compounds
React with the cellulosic fibre or form cross-linked structures on the fibre
-----W. Liu et al. Polymer Degradation and Stability 97 (2012) 2487
-----Z. Yang et al. Polymer Degradation and Stability 97 (2012) 2467
Fabrication of the Flame-Retarded Fibers of Cellulose—Wet Electrospinning
1. Coating of Cellulose with Mg(OH)2 (outside) 2. The mixture of the Cellulose and Mg(OH)2(inside)
3. Coating of the mixture of the Cellulose and Mg(OH)2 (inside & outside)
Standard Vortex Mixer
Ionic liquids
Fig. 1 TGA curves of cellulose under air and N2 atmosphere Fig. 2 TGA and DSCcurves of Nano Mg(OH)2
220-300OCMass loss:76%flame combustion
300-500OCMass loss:22%Smouldering phenomenon
Thermal Properties of Cellulose and Mg(OH)2
Fig.4 The XRD spectra of the cellulose fibers coated with nano Mg(OH)2
Fig.3 The ATR-FTIRspectra of the cellulose fibers with nano Mg(OH)2
Cellulose Coated with Mg(OH)2
Sample Tonset, ℃ Tmax,℃ Residue, wt%
Degradation of Cellulose
Degradation of Mg(OH)2
Degradation of Cellulose
Degradation of Mg(OH)2
Cellulose 239 302 0.39Coating1 254(15↑) 345(↑) 308(6↑) 358(↓) 34.4Coating2 276(37↑) 349(↑) 318(12↑) 360(↓) 31.3
Nano Mg(OH)2 339 364 66.9
Table 1 TGA and DTG data for Cellulose, Coating1, Coating2 and Nano Mg(OH)2 under air atmosphere
Fig. 5 TGA and DTG curves of Cellulose, Coating1, Coating2 and Nano Mg(OH)2 under air
atmosphere
The Flame Retardant Properties 1.1Coating(outside)
Sample Residue, wt% Content of Cellulose, wt%
Original rate, %/min
Final rate, %/min
Cellulose 0.39 100% 40.45 40.45Coating1 34.4 50.8% 8.15 16.04(↓)Coating2 31.3 53.8% 11.15 20.72(↓)
Nano Mg(OH)2 66.9 0 6.74 6.74
Table 2 Degradation rate for Cellulose, Coating1, Coating2 and Nano Mg(OH)2 under air atmosphere
Fig.6TGA and DTG curves of Cellulose, Coating1, Coating2 and Nano Mg(OH)2 under air atmosphere
Slower thermal degradation rate
Fig.7 FESEM images of electrospun fibers coated with Mg(OH)2
Lamellar-like
Coated completely
Table 3 TGA data and Degradation rate for Cellulose, Mixture(1:2), Mixture(1:1) and Nano Mg(OH)2 under air atmosphere
Sample Tonset, ℃ Tmax,℃ Residue, wt%
Content of Cellulose, wt%
Origin rate, %/min
Final rate,%/min
Degradation of Cellulose
Degradation of Mg(OH)2
Degradation of Cellulose
Degradation of Mg(OH)2
Cellulose 239 302 0.39 100% 40.45 40.45Mixture(1:2) 267(↑) 348(↑) 315(↑) 356(↓) 11.3 83.7% 27.3 32.62(↓)
Mixture(1:1) 271(↑) 349(↑) 314(↑) 361(↓) 30.5 55.0% 12.8 23.27(↓)
NanoMg(OH)2
339 364 66.9 0 6.74 6.74
Fig. 8 TGA and DTG curves of Cellulose, Mixture(1:2), Mixture(1:1) and Nano Mg(OH)2 under air atmosphere
1.2 Mixture (inside)The Flame Retardant Properties
Fig.9 FESEM images of electrospun fibers of 1:2 Mixture
1.3 Mixture &Coating (inside &outside)
Fig. 10 TGA curves of Cellulose, Coating ,Mixture, Mixture&Coating and Nano Mg(OH)2 under air atmosphere
The Flame Retardant Properties
Fig.11 FESEM images of electrospun fibers of Mixture&Coating
Flame Test
Sample Residue, wt% Content of Cellulose, wt% Quality of sample, needed for flame test(actual quality), mg
Cellulose 0.39 100% 100(30)
Coating1 34.4 50.8% 197
Coating2 31.3 53.8% 186(56)
Mixture(1:2) 11.3 83.7% 119(36)
Mixture(1:1) 30.5 55.0% 182
Mixture&Coating 28.1 58.6% 171(51)Nano Mg(OH)2 66.9 0 0
Table 4 Quality of sample needed for flame test(mg)
Mg(OH)2 (58) H2O + MgO(40)
Cellulose Coating 2
Mixture (1:2) Mixture &Coating
Flame Test
Conclusion
A novel nanofiber synthesis technique that embeds nanoparticles into the surface of wet electrospun cellulose fibers was reported.
Effective surface coating of cellulose fibers with Mg(OH)2improved the flame resistant performance greatly.
This wet electrospinning technique can also be applied to expand cotton fibers' application with different coating material, such as TiO2, Ag, etc.
Acknowledgement
• Prof. Robert J. Linhardt• Dr. Trevor J Simmons• Dr. Jianjun Miao• Dr. Guoyun Li