Dr.Sathish Babu B
Department of Textile Technology, PSG Polytechnic College, Coimbatore 641004, Tamil Nadu, India
sathishbabu645@gmail.com
Abstract
The object of the study is to evaluate the flame-resistant property of cotton fabric treated with Banana pseudo-stem sap (BPS), Spinacia oleracea juice (SJ) and Borax. Banana pseudo-stem sap (BPS) has been extracted from the outer sheath of pseudo-stem of banana tree (Musa Cavendish). It looks like colorless clean water immediately after extraction. However, with the passage of time, it slowly turns into a light khaki color due to the oxidation of phenolic rings present in it. Spinacia oleracea is a plant species belonging to the family Chenopodiaceae. It has been extracted from the leaves. Borax is a common name for the chemical sodium tetraborate. It is a salt of boric acid. Banana pseudo-stem sap (BPS) extract, Spinacia oleracea juice (SJ) extract and Borax was applied on the cotton fabric by Pad –Dry-Cure technique. The finished fabric is subjected for testing limited oxygen index (LOI), Flammability and Scanning Electron Microscopy (SEM). Then the finished fabrics are made as kitchen products of apron, kitchen towel and mittens. From this study, it was found that Spinacia oleracea juice (SJ) extract applied on cotton fabric shows better results for flame resistant characteristics when compared to Banana pseudo-stem sap (BPS) extract and Borax.
Introduction
Cotton fabric has been widely used due to its outstanding performance such as air permeability, comfortability, hydrophilicity, softness, etc. It has a worldwide monopoly in the garment industry. It has many advantages, including biocompatibility, non-molting, biodegradability, hydrophilicity, softness, and comfort. For this reason, cotton fabric is used in apparel making for both adults and kids, as outdoor and indoor decorations such as curtains, carpets and kitchen textiles. Cotton fabric has soft feel, comfort, and suitable moisture evaporation properties. Due to the majority of cellulosic essence, cotton fabric is highly flammable and very hard to extinguish, causing severe health hazards and deleteriousness of textiles and wealth. There have been many efforts made in the past using several chemicals. Researchers have improved the flame retardant property of cotton fabric using different goods, those goods are available in the market but mostly fabricated products. Many types of techniques also have been applied to make fire retardant materials1. To find a balance between flame retardancy and biosafety characteristics, researchers have been trying to progress with bio-based fire-retardant materials. Researchers have been exploring plant extracts as flame retardant2. Borax and boric acid are the simplest and most common chemical compound mixtures. Many research have been made to improve the flame retardant property of cotton textile using various synthetic chemicals. The more effective fire retardant chemicals available in the market are inorganic salts, borax and boric acid mixture, etc3. Flame retardancy was imparted in cellulosic cotton textile using Banana pseudo stem sap (BPS), an eco-friendly natural product. The extracted Banana pseudo stem sap (BPS) was made alkaline and applied in pre-mordanted bleached and mercerized cotton fabrics2. Cotton fabric can be self extinguishable for flame when subjected for treating with banana pseudo stem sap and borax4,5. The eco friendly and advanced finishing extract can be used to treat the cotton fabric to improve the flame retardancy6,8. The flame retardancy characteristics can be studied by vertical flame retardant testing method7. The object of this study is to impart flame retardant finish on cotton fabric using natural extract of Banana pseudo-stem , Spinacia oleracea juice and Borax chemical and to study the effect of flame retardancy.
Materials and methods
Materials
30s bleached cotton fabric of GSM 200 is chosen for the study. Banana pseudo-stem sap (BPS), Spinacia oleracea juice (SJ) and Borax are used to give finishing treatment to the cotton fabric. The banana pseudo-stem sap and spinacia oleracea were collected and washed with distilled water and it has been grind to collect the extract.
Methods
Pad-Dry-Cure method was adopted to give the finishing treatment with banana pseudo-stem sap (BPS), Spinacia oleracea juice (SJ) and Borax. In banana pseudo-stem sap finishing, recipe with Banana pseudostem sap (BPS) – 1200ml, Tannic acid – 5%, Alum – 10%, Sodium carbonate – 3%, ML ratio – 1:10 were used. Fabric were immersed in the finishing solution for 60 mins and passed through the padding mangle, then the fabric is dried at 120c for 5 mins. In spinacia oleracea finishing, recipe with Spinacia oeracea (SJ) – 1200ml, Tannic acid – 5%, Alum – 10%, ML ratio – 1:10 were used. Fabric were immersed in the solution for 60 mins at 90c and passed through the padding mangle, then the fabric is dried at 120c for 5 mins. In borax finishing, recipe with Borax – 5%, Boric acid – 5%, Sodium phosphate – 3%, ML ratio – 1:10 were used. Fabric were immersed in the solution for 60 mins and passed through padding mangle, then the fabric is dried at 130c for 5 mins.
Testing and evaluation
Flame resistant characteristics was tested for the fabrics treated with banana pseudo-stem sap (BPS), Spinacia oleracea juice (SJ) and Borax. The resistant to flammability of the treated fabrics was assessed according to ASTM D6413 standard test method in vertical flammability tester. Vertical flame resistance of a test specimen is measured according to ASTM D 6413 Standard test method for Flame Resistance of textiles, under controlled laboratory conditions, material response to heat and flame is measured and described. A test specimen is positioned vertically above a controlled flame and exposed for a specified period of time. Following exposure, the flame source is removed. Measurements are made on the length of time that the specimen continues to flame, and the time afterglow continues after the flame source has been removed. Char length, or visible damage to the test specimen after application of a specified tearing force, is determined. Notations on observations of melting and dripping are also recorded. The limiting oxygen index (LOI) indicates the minimum oxygen concentration in the test atmosphere to support ignition and flaming combustion of the material. The overall LOI testing method, including specimen preparation and measurement is designated in international standards such as ASTM D2863, ISO 4589-2, and NES 714. The LOI tester basically consists of a vertical glass chimney and a control unit. The heat-resistant glass tube of the chimney is 450 or 500 mm high and 75 or 100 mm in diameter. Specimen size can vary depending on the material forms, namely fabric or sheet specimens. Thin film less than 0.1 mm can be also measured using a U-shape holder. The mixture of oxygen and nitrogen flows upwards to a vertical specimen in the chimney. The upper end of the specimen is ignited by a gas flame from an igniter and the subsequent burning behaviour is observed. Generally, low LOI indicates highly flammabiity of material, while less flammable material has high LOI. The presence of the extract on the fabric surface is evaluated through the Scanning Electron Microscope (SEM).
Results and discussion
Fig.3 SEM picture of banana pseudo-stem sap treated fabric
Fig.4 SEM picture of Spinacia oleracea juice treated fabric
Fig.5 SEM picture of Borax treated fabric
The scanning electron microscope picture of cotton fabric treated with Banana pseudo-stem sap (BPS), Spinacia oleracea juice (SJ) and Borax are shown in Figs 3,4 & 5.
Table 4.1 : Vertical flammability details of borax
Direction | Warp | Warp | Warp | Warp | Warp | Weft | Weft | Weft | Weft | Weft |
| Specimen No | 1 | 2 | 3 | 4 | 5 | 1 | 2 | 3 | 4 | 5 |
| After flametime in (sec) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Char length in cm | 6.2 | 6.2 | 6.1 | 6.3 | 6.1 | 6.2 | 6.1 | 6.3 | 6.2 | 6.2 |
| Afterglow time in (sec) | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 |
| Melting /Dripping | No | No | No | No | No | No | No | No | No | No |
Five fabric samples of 15 centimetre length treated with borax has been subjected for vertical flammability test . The flame has been applied for 10 seconds in warp way and weft way and its flame behavior has been shown in Table 4.1. It was found that after glow time was observed as 5 seconds and the average char length after the test was found as 6.1 centimetres.
Table 4.2 : Vertical flammability details of Spinacia oleracea juice
Direction | Warp | Warp | Warp | Warp | Warp | Weft | Weft | Weft | Weft | Weft |
| Specimen No | 1 | 2 | 3 | 4 | 5 | 1 | 2 | 3 | 4 | 5 |
| After flametime in (sec) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Char length in cm | 4.3 | 4.1 | 4.4 | 4.1 | 4.3 | 4.4 | 4.2 | 4.1 | 4.4 | 4.3 |
| Afterglow time in (sec) | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 8 |
| Melting / Dripping | No | No | No | No | No | No | No | No | No | No |
Five fabric samples of 15 centimetre length treated with Spinacia oleracea juice has been subjected for vertical flammability test . The flame has been applied for 10 seconds in warp way and weft way and its flame behavior has been shown in Table 4.2. It was found that after glow time was observed as 8 seconds and the average char length after the test was found as 4.1 centimetres.
Table 4.3: Vertical flammability details of Banana pseudo-stem sap
Direction | Warp | Warp | Warp | Warp | Warp | Weft | Weft | Weft | Weft | Weft |
| Specimen No | 1 | 2 | 3 | 4 | 5 | 1 | 2 | 3 | 4 | 5 |
| After flame time in (sec) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Char lengthin cm | 5.5 | 5.5 | 5.3 | 5.4 | 5.2 | 5.4 | 5.3 | 5.5 | 5.5 | 5.3 |
| Afterglow time in (sec) | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
| Melting / Dripping | No | No | No | No | No | No | No | No | No | No |
Five fabric samples of 15 centimetre length treated with Banana pseudo-stem has been subjected for vertical flammability test . The flame has been applied for 10 seconds in warp way and weft way and its flame behavior has been shown in Table 4.2. It was found that after glow time was observed as 6 seconds and the average char length after the test was found as 5.3 centimetres.
Table 4.4 : Limited oxygen index value of treated and untreated sample
S.No | Sample Specification | LOI (%) |
1 | Untreated | 18 |
2 | Borax | 23 |
3 | Spinacia oleracea juice | 28 |
4 | Banana pseudo-stem | 25 |
Table 4.4 shows the LOI percentage values of untreated and treated fabrics. Treating the fabric with borax shows the LOI value of 23 % . Fabric treated with Spinach oleracea juice shows the LOI value of 28%. Also the fabric treated with Banana pseudo-stem shows the LOI value of 25%.
Kitchen Aprons, Mittens and towel
The untreated fabric and treated fabrics are sewn into kitchen textile products such as Apron, Mittens and Towel as shown below in the figure 1 and figure 2.
Fig.1 Untreated kitchen apron, mitten and towel
Fig.2 Treated kitchen apron, mitten and towel
Conclusion
In the study, to impart the flame retardancy of the cotton fabric , natural extract of Banana pseudo-stem , Spinacia oleracea juice and chemical Borax were used. The results shows that the application of Spinacia oleracea juice showed strong flammability resistant than banana pseudo-stem and borax. Also the limited oxygen index (LOI) value was found higher for Spinacia oleracea juice than banana pseudo-stem and borax.
The treated fabrics with Spinacia oleracea juice and banana pseudo-stem were sewn into kitchen products such as apron, kitchen towel and mittens which will safeguard the wearer from fire by forming a protective layer on the fabric and prevent the spreading of fire. As both Spinacia oleracea juice and banana pseudo-stem are natural and ecofriendly extract, it can be used widely to impart flame retardancy.