Flame-Resistant Cellulose Fibers with Magnesium Hydroxide Prepared by Wet Electrospinning

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1 Flame-Resistant Cellulose Fibers with Magnesium Hydroxide Prepared by Wet Electrospinning Yingying Zheng Visiting Scholar Department of Chemistry and Chemical Biology Rensselaer Polytechnic Institute, Troy, NY, USA Robert J. Linhardt, Trevor J. Simmons, Jianjun Miao 2013 Rensselaer Nanotechnology Center Research Symposium Wednesday, November 6, 2013

2 Cellulose Fiber Availability in vast quantities Good mechanical properties Biodegradability Hydrophilicity Ease of thermal degradation, ignition and burning

3 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) Z. Yang et al. Polymer Degradation and Stability 97 (2012) 2467

4 Fabrication of the Flame-Retarded Fibers of Cellulose Wet Electrospinning Ionic liquids Standard Vortex Mixer 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)

5 Thermal Properties of Cellulose and Mg(OH) O C Mass loss:76% flame combustion O C Mass loss:22% Smouldering phenomenon Fig. 1 TGA curves of cellulose under air and N 2 atmosphere Fig. 2 TGA and DSCcurves of Nano Mg(OH) 2

6 Cellulose Coated with Mg(OH) 2 Fig.3 The ATR-FTIR spectra of the cellulose fibers with nano Mg(OH) 2 Fig.4 The XRD spectra of the cellulose fibers coated with nano Mg(OH) 2

7 The Flame Retardant Properties 1.1Coating(outside) Fig. 5 TGA and DTG curves of Cellulose, Coating1, Coating2 and Nano Mg(OH) 2 under air atmosphere Table 1 TGA and DTG data for Cellulose, Coating1, Coating2 and Nano Mg(OH) 2 under air atmosphere Sample T onset, T max, Residue, wt% Degradation of Cellulose Degradation of Mg(OH) 2 Degradation of Cellulose Degradation of Mg(OH) 2 Cellulose Coating1 254(15 ) 345( ) 308(6 ) 358( ) 34.4 Coating2 276(37 ) 349( ) 318(12 ) 360( ) 31.3 Nano Mg(OH)

8 Slower thermal degradation rate Fig.6TGA and DTG curves of Cellulose, Coating1, Coating2 and Nano Mg(OH) 2 under air atmosphere Table 2 Degradation rate for Cellulose, Coating1, Coating2 and Nano Mg(OH) 2 under air atmosphere Sample Residue, wt% Content of Cellulose, wt% Original rate, %/min Final rate, %/min Cellulose % Coating % ( ) Coating % ( ) Nano Mg(OH)

9 Fig.7 FESEM images of electrospun fibers coated with Mg(OH) 2 Lamellar-like Coated completely

10 The Flame Retardant Properties 1.2 Mixture (inside) Fig. 8 TGA and DTG curves of Cellulose, Mixture(1:2), Mixture(1:1) and Nano Mg(OH) 2 under air atmosphere Table 3 TGA data and Degradation rate for Cellulose, Mixture(1:2), Mixture(1:1) and Nano Mg(OH) 2 under air atmosphere Sample T onset, T max, Residue, Degradation Degradation Degradation Degradation wt% of Cellulose of Mg(OH) 2 of Cellulose of Mg(OH) 2 Content of Cellulose, wt% Origin rate, %/min Final rate, %/min Cellulose % Mixture(1:2) 267( ) 348( ) 315( ) 356( ) % ( ) Mixture(1:1) 271( ) 349( ) 314( ) 361( ) % ( ) Nano Mg(OH) 2

11 Fig.9 FESEM images of electrospun fibers of 1:2 Mixture

12 The Flame Retardant Properties 1.3 Mixture &Coating (inside &outside) Fig. 10 TGA curves of Cellulose, Coating,Mixture, Mixture&Coating and Nano Mg(OH) 2 under air atmosphere

13 Fig.11 FESEM images of electrospun fibers of Mixture&Coating

14 Flame Test Table 4 Quality of sample needed for flame test(mg) Sample Residue, wt% Content of Cellulose, wt% Quality of sample, needed for flame test(actual quality), mg Cellulose % 100(30) Coating % 197 Coating % 186(56) Mixture(1:2) % 119(36) Mixture(1:1) % 182 Mixture&Coating % 171(51) Nano Mg(OH) Mg(OH) 2 (58) H 2 O + MgO(40)

15 Flame Test Cellulose Coating 2 Mixture (1:2) Mixture &Coating

16 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) 2 improved the flame resistant performance greatly. This wet electrospinning technique can also be applied to expand cotton fibers' application with different coating material, such as TiO 2, Ag, etc.

17 Acknowledgement Prof. Robert J. Linhardt Dr. Trevor J Simmons Dr. Jianjun Miao Dr. Guoyun Li