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Preparation and properties of cotton fabrics treated with a novel polysiloxane water repellent and flame retardant
Materials Letters 152 (2015) 276–279
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Preparation and properties of cotton fabrics treated with a novel polysiloxane water repellent and flame retardant Chaohong Dong n, Zhou Lu, Fengjun Zhang, Ping Zhu, Lin Zhang, Shuying Sui College of Chemical Science and Engineering, Laboratory of Fiber materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071, China
art ic l e i nf o
a b s t r a c t
Article history: Received 13 January 2015 Accepted 14 March 2015 Available online 4 April 2015
Iodine butyl-N-sulfonate amino polysiloxane [(IB-N-SA) PDMS] was synthesized as a novel water repellent and flame retardant and it was characterized by FT-IR. The water repellency of treated cotton fabric with (IB-N-SA) PDMS was studied and the results showed that the water contact angle increased from 88.371 to 124.491. The flame retardant properties of treated cotton fabric were evaluated by limiting oxygen index (LOI) and the vertical burning test. The treated cotton fabric obtained good flame retardancy with a LOI value of 30.9%. Furthermore, The combustion properties of treated cotton fabric were assessed by cone calorimeter and it demonstrated that the treated cotton fabric with (IB-N-SA) PDMS generated less combustion heat and obtained better flame retardancy which can be confirmed by the increase of TTI and FPI values and the decrease in the values of HRR, THR, EHC, Mass loss and CO2/CO ratio. & 2015 Elsevier B.V. All rights reserved.
Keywords: Flame retardant Combustion behavior Water repellency Cotton fabric Functional Polymers
1. Introduction Cotton is tremendously popular in civilian and military applications (clothing, wall-hangings, bedding materials, firefighter apparel and military garments) due to its good mechanical properties, biodegradability and air permeability [1–3]. However, cotton faces certain shortcomings such as ease to ignition, microbial infection and poor water repellency [4–6]. Cotton-related burn injuries and financial losses have been a worldwide problem and many repeated attempts have been made to develop flame retardant cotton fabric [7]. The flame retardancy of cotton fabric can be achieved by chemical treatment and halogen-based and formaldehyde-based flame retardants have shown remarkable flame retardancy in the past decades [8,9]. However, formaldehyde is known as a carcinogenic compound by World Health Organization and halogen-containing compounds in the combustion will release hydrogen halide toxic and corrosive gases [10]. Therefore, government regulations for fire safety and concerns over the toxicological and environmental consequences of these flame retardants have fueled the search for environmentally friendly and cost-effective alternatives [11]. In recent years, silicone-based flame retardants have been a research hotspot in academic. These compounds possess good thermal stability, low fire hazard and biological compatibility [12,13]. The flame retarding mechanism is explained as that the flame retardants migrate to the
n
Corresponding author. Tel.: þ 86 053285951290. E-mail address: [email protected] (C. Dong).
http://dx.doi.org/10.1016/j.matlet.2015.03.132 0167-577X/& 2015 Elsevier B.V. All rights reserved.
material surface and produce silicaceous char layer during combustion. Furthermore, synergistic effect of silicon and other elements on enhancing flame retardancy of cotton fabric is previously observed [14]. The interest in improvement of water repellency of cotton has been increased recently. Cotton treated with fluorinated compounds can obtain high water repellency. However, fluorinated compounds have potential risk to humans and the environment [15]. Nowadays, silicon compounds have been a good option because they can create a hydrophobic surface and they are ecofriendly [16]. The development of cotton fabrics with multifunctional features is attracting more attention. In this work, Iodine butyl-N-sulfonate amino polysiloxane [(IBN-SA) PDMS] was synthesized as a novel agent with double functions of water repellency and flame retardancy using poly (4-iodobutoxy) methylsiloxane and guanidine sulfamate as raw materials. It was applied to cotton fabrics and it could combine to cotton fabrics with covalent bond due to the activity group. The water repellency and flame retardancy of treated cotton fabrics with (IB-N-SA) PDMS were evaluated by water contact angle and limiting oxygen index (LOI). The combustion behaviors of treated cotton fabrics were investigated by cone calorimeter.
2. Experimental Materials: Scoured and bleached 100% plain-woven cotton fabric (14.75 14.75 tex2, 122 g/m2) was purchased from Weifang Qirong Textiles Co., Ltd.
C. Dong et al. / Materials Letters 152 (2015) 276–279
Poly (4-iodobutoxy) methylsiloxane was self-made in our laboratory. Guanidine sulfamate was supplied by Tangshan Sanding Chemicals Co., Ltd. Zirconium oxychloride was obtained from Aladdin Reagent Co., Ltd. Preparation of (IB-N-SA) PDMS: Iodine butyl-N-sulfonate amino polysiloxane [(IB-N-SA) PDMS] was synthesized using poly (4-iodobutoxy) methylsiloxane and guanidine sulfamate as raw materials. The structure of (IB-N-SA) PDMS is shown in Scheme 1 and it is characterized by FT-IR. FT-IR: the absorption peak at 3352–3198 cm 1 was symmetrical and asymmetrical stretching vibration of N–H and absorption peaks at 1667 cm 1 was assigned to stretching vibration of CQN; the absorption peak at about 1241 cm 1 was stretching vibration of C–N and the absorption peak at about 1053 cm 1 was stretching vibration of Si–O–Si. Preparation of treated cotton fabrics: The cotton fabrics were soaked in finishing bath containing (IB-N-SA) PDMS, zirconium oxide chloride and urea at room temperature for 4 min under proper pH condition. Then the samples passed through a laboratory-scale padder with two dips and two nips to get a wet pick up of 100%. Finally, the samples were dried at 100 1C for 3 min and cured at 150 1C for 4 min. The amount (wt% owf) of flame retardant added on cotton fabric was calculated as follows: Add on% ¼
CH3 H3C
Si CH3
Wf Wb 100% Wb
CH3 O
Si
CH3
CH3 O
Si
O
CH3
n CH 3
m O
CH3
O
NH
Si
+
H2N
C
NH2HO S NH2 O
CH2 CH2
O CH2 N C NH2 HO S NH2
CH2
H2C
CH2
O
NH2
CH2
I
H2C CH3 H3C
Si CH3
CH3 O
Si CH3
O
CH3 O
Si
m
O
O
Si
a
CH3
CH3 O
Si
b
CH3
CH2 CH2 CH2 CH2 I
Scheme 1. Preparation of (IB-N-SA) PDMS.
CH3
277
where Wb and Wf represent the weights of cotton fabrics before and after flame retardant treatment, respectively. Characterization: The water repellent properties of the fabrics were evaluated in accordance with AATCC Test Method 22. Hydrophobic properties were also characterized by an Easy Drop video optical contact angle meter. The contact angle was calculated using the formula θ ¼2 tan 1 (2 h/d), where h is the height of the water droplet and d is the width of the droplet touching the film. Limited oxygen index (LOI) tests were carried out on a digital display oxygen index instrument LFY-606 according to GB/T 54542009. The vertical burning test was carried out on CZF-3 instrument according to GB/T 5455-2009. The combustion of cotton fabrics was investigated using a FTT0007 cone calorimeter (Fire Testing Technology Ltd.) under a heat flux of 30 kW/m2 according to ISO 5660.
3. Results and discussion Water repellency: The water repellent properties of the cotton fabrics treated with (IB-N-SA) PDMS were evaluated and the grade of water repellency of treated cotton fabric was 90. Furthermore, the water contact angle of treated cotton fabric increased from 88.371 to 124.491 as shown in Fig. 1. The reason of the improvement of water repellency was that (IB-N-SA) PDMS could react with cotton fiber and the groups which oriented on fiber surface, mainly methyl groups, formed a hydrophobic film, decreasing the critical surface tension of cotton fabric [17]. Flame retardant performance: The flammable properties of cotton fabrics were investigated and the results showed that the LOI value of treated cotton fabric increased from 18.0% to 30.9%. The upward burning behaviors of cotton fabrics were also determined by the vertical burning test and the results demonstrated that the untreated cotton fabric was completely destroyed while the treated cotton fabric obtained shorter char length (3.8 cm), shorter after-glow time (4 s) and no after-flame which indicated that the flammability of cotton fabric was retarded by (IB-N-SA) PDMS. The reason was that (IB-N-SA) PDMS decomposed during degradation and produced the incombustible gases which can dilute the concentration of the flammable gases and formed the foamed-char layers. Furthermore, (IB-N-SA)PDMS also produced silica and glassy char, which acted as a physical barrier and could protect cotton fabric from heat and oxygen transfer. Combustion behaviors: Cone calorimeter was employed to investigate the combustion properties of cotton fabrics, the results are shown in Fig. 2 and the critical data related to the combustibility are presented in Table 1. The treated cotton fabric with (IB-N-SA) PDMS obtained a remarkable reduction in heat release rate (HRR), corresponding peak HRR (PHRR) and total heat release rate (THR)
Fig. 1. Contact angles of the cotton fabrics: (a) the untreated fabric (θ ¼88.371); (b) the treated fabric with (IB-N-SA) PDMS (θ¼ 124.491).
278
C. Dong et al. / Materials Letters 152 (2015) 276–279
160 Untreated fabric Treated fabric
140
30
120
25
EHC[MJ/kg]
100 HRR[kW/m ]
Untreated fabric Treated fabric
35
80 60
20 15 10
40 5
20 0
0
-20
-5 0
50
100
150
200
0
250
50
Time[s]
18
150
200
250
Time[s]
Untreated fabric Treated fabric
16
100
14 Untreated fabric Treated fabric
12 12
10
10
8
Mass[g]
THR[MJ/m ]
14
8 6
6 4
4 2
2
0
0
-2 0
50
100
150
200
250
0
50
100
150
200
250
Time[s]
Time[s]
Fig. 2. Combustion curves of untreated and treated cotton fabrics with (IB-N-SA) PDMS: (a) HRR curves, (b) THR curves, (c) EHC curves and (d) mass curves.
4. Conclusions
Table 1 Combustion data by a cone calorimeter. Addon%
TTI (s)
PHRR (kW/m2)
FPI (s m2/ Average EHC kW) (MJ/kg)
CO (kg/ CO2 (kg/ CO2/ kg) kg) CO
0 21.5
2 15
144.23 40.70
0.01 0.37
0.10 0.34
12.57 10.17
2.33 2.44
23.30 7.18
as shown in Fig. 2(a) and (b), and Table 1. It demonstrates that (IB-N-SA) PDMS could retard the combustion of cotton fabric effectively as evident by the extension of time to ignition (TTI, 15 s vs. 2 s) and the increase of FPI value (the ratio between TTI and PHRR, 0.37 s m2/kW vs. 0.01 s m2/kW) as collected in Table 1. The higher the FPI, the better is the flame retardancy of materials. EHC (effective heat combustion) and Mass loss are also important parameters that can reflect the combustibility of cotton fabrics as shown in Fig. 2(c) and (d). It can be seen that EHC value of the treated cotton fabric has decreased compared to untreated cotton fabric (10.17 MJ/kg vs. 12.57 MJ/kg) which means the reduction of heat released from volatile portion. The Mass loss value of treated cotton fabric is much lower than untreated one's (5.51 g vs. 12.32 g) and it indicates the incomplete combustion of cotton fabric. Lower CO2/CO ratio suggested inefficient combustion of materials [18]. From Table 1, we can know that the CO2/CO ratio of treated cotton fabric has decreased significantly (7.18 vs. 23.30). All these demonstrate that the flame retardancy of cotton fabric have been enhanced due to the employment of (IB-N-SA) PDMS.
A novel water repellent and flame retardant for cotton fabrics, Iodine butyl-N-sulfonate amino polysiloxane [(IB-N-SA) PDMS] was successfully synthesized and it was characterized by FT-IR. The grade of water repellency of treated cotton fabric was 90 and the water contact angle increased from 88.371 to 124.491. The flame retardancy of treated cotton fabric was enhanced with a LOI value of 30.9%. Moreover, the combustion behaviors of the cotton fabric treated with (IB-N-SA) PDMS were evaluated by cone calorimeter. The results showed that the TTI value of the treated fabric increased and the values of HRR, THR, EHC, Mass loss decreased. It demonstrated that (IB-N-SA) PDMS favored the char formation of cotton fiber during combustion and the treated cotton fabric generated less combustion heat and obtained better flame retardancy which can be confirmed by the increase of FPI value and the decrease of CO2/CO ratio.
Acknowledgment This work was supported by The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry. References [1] Ghoranneviss M, Shahidi S. J Fusion Energy 2014;33:119–24. [2] Ceylan O, Alongi J, Van Landuyt L, Frache A, De Clerck K. Fire Mater 2013;37:482–90.
C. Dong et al. / Materials Letters 152 (2015) 276–279
[3] [4] [5] [6] [7] [8] [9] [10] [11]
Zhao J, Zhang X, Tu R, Lu C, He X, Zhang W. Cellulose 2014;21:1859–72. Kaur I, Bhati P, Sharma B. J Appl Polym Sci 2014;131:40415–8. Dogan M. J Therm Anal Calorim 2014;118:93–8. Huang G, Gao J, Wang X, Liang H, Ge C. Mater Lett 2012;66:187–9. Guin T, Krecker M, Milhorn A, Grunlan JC. Cellulose 2014;21:3023–30. Xie K, Gao A, Zhang Y. Carbohydr Polym 2013;98:706–10. Horrocks AR. Polym Degrad Stab 2013;98:2813–24. Yang Z, Wang X, Lei D, Fei B, Xin JH. Polym Degrad Stab 2012;97:2467–72. Chang S, Slopek RP, Condon B, Grunlan JC. Ind Eng Chem Res 2014;53:3805–12. [12] Mohamed AL, El-Sheikh MA, Waly AI. Carbohydr Polym 2014;102:727–37.
[13] [14] [15] [16]
279
Yang S, Lv G, Liu Y, Wang Q. Polym Degrad Stab 2013;98:2795–800. Yang Z, Fei B, Wang X, Xin JH. Fire Mater 2012;36:31–9. Davis R, El-Shafei A, Hauser P. Surf Coat Technol 2011;205:4791–7. Tsougeni K, Tserepi A, Boulousis G, Constantoudis V, Gogolides E. Plasma Process Polym 2007;4:398–405. [17] Tragoonwichian S, Kothary P, Siriviriyanun A, O'Rear EA, Yanumet N. Colloid Surf A 2011;384:381–7. [18] Nazare S, Kandola BK, Horrocks AR. J Fire Sci 2008;26:215–42.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
Preparation and properties of cotton fabrics treated with a novel polysiloxane water repellent and flame retardant Chaohong Dong n, Zhou Lu, Fengjun Zhang, Ping Zhu, Lin Zhang, Shuying Sui College of Chemical Science and Engineering, Laboratory of Fiber materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071, China
art ic l e i nf o
a b s t r a c t
Article history: Received 13 January 2015 Accepted 14 March 2015 Available online 4 April 2015
Iodine butyl-N-sulfonate amino polysiloxane [(IB-N-SA) PDMS] was synthesized as a novel water repellent and flame retardant and it was characterized by FT-IR. The water repellency of treated cotton fabric with (IB-N-SA) PDMS was studied and the results showed that the water contact angle increased from 88.371 to 124.491. The flame retardant properties of treated cotton fabric were evaluated by limiting oxygen index (LOI) and the vertical burning test. The treated cotton fabric obtained good flame retardancy with a LOI value of 30.9%. Furthermore, The combustion properties of treated cotton fabric were assessed by cone calorimeter and it demonstrated that the treated cotton fabric with (IB-N-SA) PDMS generated less combustion heat and obtained better flame retardancy which can be confirmed by the increase of TTI and FPI values and the decrease in the values of HRR, THR, EHC, Mass loss and CO2/CO ratio. & 2015 Elsevier B.V. All rights reserved.
Keywords: Flame retardant Combustion behavior Water repellency Cotton fabric Functional Polymers
1. Introduction Cotton is tremendously popular in civilian and military applications (clothing, wall-hangings, bedding materials, firefighter apparel and military garments) due to its good mechanical properties, biodegradability and air permeability [1–3]. However, cotton faces certain shortcomings such as ease to ignition, microbial infection and poor water repellency [4–6]. Cotton-related burn injuries and financial losses have been a worldwide problem and many repeated attempts have been made to develop flame retardant cotton fabric [7]. The flame retardancy of cotton fabric can be achieved by chemical treatment and halogen-based and formaldehyde-based flame retardants have shown remarkable flame retardancy in the past decades [8,9]. However, formaldehyde is known as a carcinogenic compound by World Health Organization and halogen-containing compounds in the combustion will release hydrogen halide toxic and corrosive gases [10]. Therefore, government regulations for fire safety and concerns over the toxicological and environmental consequences of these flame retardants have fueled the search for environmentally friendly and cost-effective alternatives [11]. In recent years, silicone-based flame retardants have been a research hotspot in academic. These compounds possess good thermal stability, low fire hazard and biological compatibility [12,13]. The flame retarding mechanism is explained as that the flame retardants migrate to the
n
Corresponding author. Tel.: þ 86 053285951290. E-mail address: [email protected] (C. Dong).
http://dx.doi.org/10.1016/j.matlet.2015.03.132 0167-577X/& 2015 Elsevier B.V. All rights reserved.
material surface and produce silicaceous char layer during combustion. Furthermore, synergistic effect of silicon and other elements on enhancing flame retardancy of cotton fabric is previously observed [14]. The interest in improvement of water repellency of cotton has been increased recently. Cotton treated with fluorinated compounds can obtain high water repellency. However, fluorinated compounds have potential risk to humans and the environment [15]. Nowadays, silicon compounds have been a good option because they can create a hydrophobic surface and they are ecofriendly [16]. The development of cotton fabrics with multifunctional features is attracting more attention. In this work, Iodine butyl-N-sulfonate amino polysiloxane [(IBN-SA) PDMS] was synthesized as a novel agent with double functions of water repellency and flame retardancy using poly (4-iodobutoxy) methylsiloxane and guanidine sulfamate as raw materials. It was applied to cotton fabrics and it could combine to cotton fabrics with covalent bond due to the activity group. The water repellency and flame retardancy of treated cotton fabrics with (IB-N-SA) PDMS were evaluated by water contact angle and limiting oxygen index (LOI). The combustion behaviors of treated cotton fabrics were investigated by cone calorimeter.
2. Experimental Materials: Scoured and bleached 100% plain-woven cotton fabric (14.75 14.75 tex2, 122 g/m2) was purchased from Weifang Qirong Textiles Co., Ltd.
C. Dong et al. / Materials Letters 152 (2015) 276–279
Poly (4-iodobutoxy) methylsiloxane was self-made in our laboratory. Guanidine sulfamate was supplied by Tangshan Sanding Chemicals Co., Ltd. Zirconium oxychloride was obtained from Aladdin Reagent Co., Ltd. Preparation of (IB-N-SA) PDMS: Iodine butyl-N-sulfonate amino polysiloxane [(IB-N-SA) PDMS] was synthesized using poly (4-iodobutoxy) methylsiloxane and guanidine sulfamate as raw materials. The structure of (IB-N-SA) PDMS is shown in Scheme 1 and it is characterized by FT-IR. FT-IR: the absorption peak at 3352–3198 cm 1 was symmetrical and asymmetrical stretching vibration of N–H and absorption peaks at 1667 cm 1 was assigned to stretching vibration of CQN; the absorption peak at about 1241 cm 1 was stretching vibration of C–N and the absorption peak at about 1053 cm 1 was stretching vibration of Si–O–Si. Preparation of treated cotton fabrics: The cotton fabrics were soaked in finishing bath containing (IB-N-SA) PDMS, zirconium oxide chloride and urea at room temperature for 4 min under proper pH condition. Then the samples passed through a laboratory-scale padder with two dips and two nips to get a wet pick up of 100%. Finally, the samples were dried at 100 1C for 3 min and cured at 150 1C for 4 min. The amount (wt% owf) of flame retardant added on cotton fabric was calculated as follows: Add on% ¼
CH3 H3C
Si CH3
Wf Wb 100% Wb
CH3 O
Si
CH3
CH3 O
Si
O
CH3
n CH 3
m O
CH3
O
NH
Si
+
H2N
C
NH2HO S NH2 O
CH2 CH2
O CH2 N C NH2 HO S NH2
CH2
H2C
CH2
O
NH2
CH2
I
H2C CH3 H3C
Si CH3
CH3 O
Si CH3
O
CH3 O
Si
m
O
O
Si
a
CH3
CH3 O
Si
b
CH3
CH2 CH2 CH2 CH2 I
Scheme 1. Preparation of (IB-N-SA) PDMS.
CH3
277
where Wb and Wf represent the weights of cotton fabrics before and after flame retardant treatment, respectively. Characterization: The water repellent properties of the fabrics were evaluated in accordance with AATCC Test Method 22. Hydrophobic properties were also characterized by an Easy Drop video optical contact angle meter. The contact angle was calculated using the formula θ ¼2 tan 1 (2 h/d), where h is the height of the water droplet and d is the width of the droplet touching the film. Limited oxygen index (LOI) tests were carried out on a digital display oxygen index instrument LFY-606 according to GB/T 54542009. The vertical burning test was carried out on CZF-3 instrument according to GB/T 5455-2009. The combustion of cotton fabrics was investigated using a FTT0007 cone calorimeter (Fire Testing Technology Ltd.) under a heat flux of 30 kW/m2 according to ISO 5660.
3. Results and discussion Water repellency: The water repellent properties of the cotton fabrics treated with (IB-N-SA) PDMS were evaluated and the grade of water repellency of treated cotton fabric was 90. Furthermore, the water contact angle of treated cotton fabric increased from 88.371 to 124.491 as shown in Fig. 1. The reason of the improvement of water repellency was that (IB-N-SA) PDMS could react with cotton fiber and the groups which oriented on fiber surface, mainly methyl groups, formed a hydrophobic film, decreasing the critical surface tension of cotton fabric [17]. Flame retardant performance: The flammable properties of cotton fabrics were investigated and the results showed that the LOI value of treated cotton fabric increased from 18.0% to 30.9%. The upward burning behaviors of cotton fabrics were also determined by the vertical burning test and the results demonstrated that the untreated cotton fabric was completely destroyed while the treated cotton fabric obtained shorter char length (3.8 cm), shorter after-glow time (4 s) and no after-flame which indicated that the flammability of cotton fabric was retarded by (IB-N-SA) PDMS. The reason was that (IB-N-SA) PDMS decomposed during degradation and produced the incombustible gases which can dilute the concentration of the flammable gases and formed the foamed-char layers. Furthermore, (IB-N-SA)PDMS also produced silica and glassy char, which acted as a physical barrier and could protect cotton fabric from heat and oxygen transfer. Combustion behaviors: Cone calorimeter was employed to investigate the combustion properties of cotton fabrics, the results are shown in Fig. 2 and the critical data related to the combustibility are presented in Table 1. The treated cotton fabric with (IB-N-SA) PDMS obtained a remarkable reduction in heat release rate (HRR), corresponding peak HRR (PHRR) and total heat release rate (THR)
Fig. 1. Contact angles of the cotton fabrics: (a) the untreated fabric (θ ¼88.371); (b) the treated fabric with (IB-N-SA) PDMS (θ¼ 124.491).
278
C. Dong et al. / Materials Letters 152 (2015) 276–279
160 Untreated fabric Treated fabric
140
30
120
25
EHC[MJ/kg]
100 HRR[kW/m ]
Untreated fabric Treated fabric
35
80 60
20 15 10
40 5
20 0
0
-20
-5 0
50
100
150
200
0
250
50
Time[s]
18
150
200
250
Time[s]
Untreated fabric Treated fabric
16
100
14 Untreated fabric Treated fabric
12 12
10
10
8
Mass[g]
THR[MJ/m ]
14
8 6
6 4
4 2
2
0
0
-2 0
50
100
150
200
250
0
50
100
150
200
250
Time[s]
Time[s]
Fig. 2. Combustion curves of untreated and treated cotton fabrics with (IB-N-SA) PDMS: (a) HRR curves, (b) THR curves, (c) EHC curves and (d) mass curves.
4. Conclusions
Table 1 Combustion data by a cone calorimeter. Addon%
TTI (s)
PHRR (kW/m2)
FPI (s m2/ Average EHC kW) (MJ/kg)
CO (kg/ CO2 (kg/ CO2/ kg) kg) CO
0 21.5
2 15
144.23 40.70
0.01 0.37
0.10 0.34
12.57 10.17
2.33 2.44
23.30 7.18
as shown in Fig. 2(a) and (b), and Table 1. It demonstrates that (IB-N-SA) PDMS could retard the combustion of cotton fabric effectively as evident by the extension of time to ignition (TTI, 15 s vs. 2 s) and the increase of FPI value (the ratio between TTI and PHRR, 0.37 s m2/kW vs. 0.01 s m2/kW) as collected in Table 1. The higher the FPI, the better is the flame retardancy of materials. EHC (effective heat combustion) and Mass loss are also important parameters that can reflect the combustibility of cotton fabrics as shown in Fig. 2(c) and (d). It can be seen that EHC value of the treated cotton fabric has decreased compared to untreated cotton fabric (10.17 MJ/kg vs. 12.57 MJ/kg) which means the reduction of heat released from volatile portion. The Mass loss value of treated cotton fabric is much lower than untreated one's (5.51 g vs. 12.32 g) and it indicates the incomplete combustion of cotton fabric. Lower CO2/CO ratio suggested inefficient combustion of materials [18]. From Table 1, we can know that the CO2/CO ratio of treated cotton fabric has decreased significantly (7.18 vs. 23.30). All these demonstrate that the flame retardancy of cotton fabric have been enhanced due to the employment of (IB-N-SA) PDMS.
A novel water repellent and flame retardant for cotton fabrics, Iodine butyl-N-sulfonate amino polysiloxane [(IB-N-SA) PDMS] was successfully synthesized and it was characterized by FT-IR. The grade of water repellency of treated cotton fabric was 90 and the water contact angle increased from 88.371 to 124.491. The flame retardancy of treated cotton fabric was enhanced with a LOI value of 30.9%. Moreover, the combustion behaviors of the cotton fabric treated with (IB-N-SA) PDMS were evaluated by cone calorimeter. The results showed that the TTI value of the treated fabric increased and the values of HRR, THR, EHC, Mass loss decreased. It demonstrated that (IB-N-SA) PDMS favored the char formation of cotton fiber during combustion and the treated cotton fabric generated less combustion heat and obtained better flame retardancy which can be confirmed by the increase of FPI value and the decrease of CO2/CO ratio.
Acknowledgment This work was supported by The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry. References [1] Ghoranneviss M, Shahidi S. J Fusion Energy 2014;33:119–24. [2] Ceylan O, Alongi J, Van Landuyt L, Frache A, De Clerck K. Fire Mater 2013;37:482–90.
C. Dong et al. / Materials Letters 152 (2015) 276–279
[3] [4] [5] [6] [7] [8] [9] [10] [11]
Zhao J, Zhang X, Tu R, Lu C, He X, Zhang W. Cellulose 2014;21:1859–72. Kaur I, Bhati P, Sharma B. J Appl Polym Sci 2014;131:40415–8. Dogan M. J Therm Anal Calorim 2014;118:93–8. Huang G, Gao J, Wang X, Liang H, Ge C. Mater Lett 2012;66:187–9. Guin T, Krecker M, Milhorn A, Grunlan JC. Cellulose 2014;21:3023–30. Xie K, Gao A, Zhang Y. Carbohydr Polym 2013;98:706–10. Horrocks AR. Polym Degrad Stab 2013;98:2813–24. Yang Z, Wang X, Lei D, Fei B, Xin JH. Polym Degrad Stab 2012;97:2467–72. Chang S, Slopek RP, Condon B, Grunlan JC. Ind Eng Chem Res 2014;53:3805–12. [12] Mohamed AL, El-Sheikh MA, Waly AI. Carbohydr Polym 2014;102:727–37.
[13] [14] [15] [16]
279
Yang S, Lv G, Liu Y, Wang Q. Polym Degrad Stab 2013;98:2795–800. Yang Z, Fei B, Wang X, Xin JH. Fire Mater 2012;36:31–9. Davis R, El-Shafei A, Hauser P. Surf Coat Technol 2011;205:4791–7. Tsougeni K, Tserepi A, Boulousis G, Constantoudis V, Gogolides E. Plasma Process Polym 2007;4:398–405. [17] Tragoonwichian S, Kothary P, Siriviriyanun A, O'Rear EA, Yanumet N. Colloid Surf A 2011;384:381–7. [18] Nazare S, Kandola BK, Horrocks AR. J Fire Sci 2008;26:215–42.