Effect of Low Temperature Plasma Treatment on the Dyeability of Regenerated Bamboo/Cotton Blended Fabrics

Abstract

In this research, regenerated bamboo (viscose)/cotton blended fabrics were treated with low temperature plasma under various treatment conditions (i.e., oxygen flow rate, jet-to-substrate distance, and plasma treatment time) to evaluate how these parameters influenced fabric dyeing properties. It was shown that low temperature plasma treatment can modify polymer surfaces and change the substrate's properties, such as wettability. In this study, plasma-treated fabrics were dyed with mono-functional and bi-functional reactive dyes to check for changes in CIELAB, ΔE*, and color yield values. The study concluded that color yield of the plasma-treated fabric was better when dyed to a color depth of 3%.

Introduction

Environmentally-friendly textile manufacturing processes have grown in recent decades. ¹ To make the dyeing of regenerated bamboo (viscose)/cotton blended fabric more environment-friendly, plasma treatment before coloration was used. Plasma treatment is an effective pretreatment for improving and altering surface properties of materials without inducing much change in bulk properties.^2,3Plasma treatment was found effective in improving the wettability of fabrics due to surface etching and chemical composition change.^4–8 After oxygen plasma treatment, the regenerated bamboo/cotton blended fabric surface became rougher and had more hydroxyl groups in the fabric structure. These physical and chemical changes increased the wettability of the fabric.^9–13 With increased wettability and a rougher surface, dye molecules can penetrate the fabric more easily. Thus, dye exhaustion by the regenerated bamboo and cotton fabric increased and less dye was required; production and waste treatment costs declined and the process was more environmentally friendly. In this research, the effect of low temperature plasma treatment on dyeability of regenerated bamboo/cotton blended fabrics was studied.

Experimental

Material

The scoured and bleached fabric used was a 3/3 twill woven fabric with cotton warp (27.8 tex) and regenerated bamboo weft (35.3 tex). The warp density was 30 ends/cm and weft was 25 picks/cm. Fabric weight was 0.02 g/cm².

Pretreatment

Before plasma treatment, the fabrics were washed with 10 g/L nonionic detergent, Diadavin EWN-T 200% (Tanatex), for 10 min to remove dirt and were then rinsed with deionized (DI) water. The washed fabrics were dried completely in an oven at 70 °C, and then conditioned under standard conditions at 21 ± 1 °C and 65% ± 2% relative humidity (RH) for 24 h according to BS EN ISO 139: 2005, Textiles-Standard Atmospheres for Conditioning and Testing.

Plasma Treatment

Plasma treatment on regenerated bamboo/cotton blended fabric was carried out using a Surfx Atomfo 400-Series Atmospheric Plasma system. Helium (99.95% purity) and oxygen (99.7% purity) were used as carrier and reactive gases, respectively. Treatment was carried out using a rectangular nozzle, which covered an active area of 1 × 25 mm² and was mounted vertically above the substrate. This plasma system was designed for continuous processing of treated textile materials.^3,4,10 The helium flow rate was kept at 10 L/min during treatment and the output power used was 150 W. The parameters used included jet-to-substrate distance (1 mm, 3 mm, and 5 mm), oxygen flow rate (0.1 L/min, 0.3 L/min, and 0.5 L/min), and treatment time (0.1 s, 0.5 s, and 1 s). The details are shown in Table I. The plasma-treated fabrics were stored under standard temperature and RH for 24 h prior to further evaluation.

Table I

Plasma Treatment Conditions

Treatment Condition	Oxygen Flow Rate (L/min)	Jet-to-Substrate Distance (mm)	Treatment Time (s)
1	0.1	1	0.1
2	0.1	1	0.5
3	0.1	1	1.0
4	0.1	3	0.1
5	0.1	3	0.5
6	0.1	3	1.0
7	0.1	5	0.1
8	0.1	5	0.5
9	0.1	5	1.0
10	0.3	1	0.1
11	0.3	1	0.5
12	0.3	1	1.0
13	0.3	3	0.1
14	0.3	3	0.5
15	0.3	3	1.0
16	0.3	5	0.1
17	0.3	5	0.5
18	0.3	5	1.0
19	0.5	1	0.1
20	0.5	1	0.5
21	0.5	1	1.0
22	0.5	3	0.1
23	0.5	3	0.5
24	0.5	3	1.0
25	0.5	5	0.1
26	0.5	5	0.5
27	0.5	5	1.0

Dyeability

Specimens were dyed with 0.1%, 1% and 3% mono-functional reactive dye (Remazol Brilliant Blue R, C.I. Reactive Blue 19, RB19) and bi-functional reactive dye (Remazol Black B, C.I. Reactive Red 5, RB5) at a liquor-to-goods (LR) ratio of 50:1. Two samples were dyed for each concentration to obtain average results. Conditioned samples (7.5 × 7.5 cm) were used. An oscillating dyeing machine (Tung Shing Machinery) was used for dyeing. The dyeing parameters and the dyeing profile of the specimens are shown in Table II and Fig. 1, respectively. After dyeing, fabric samples were washed with 10% nonionic detergent at 90 °C for 3 min to remove the unfixed and hydrolyzed reactive dyes. The washed fabric samples were then completely dried and conditioned at standard temperature and RH for 24 h. Measurements were made using a Macbeth Color Eye 7000A spectrophotometer. The face of the specimen was measured and conditions for measurement were set as standard observer 2° and illuminant D₆₅. Measurements of two specimens treated under the same parameters were averaged.

Fig. 1

Dyeing profile.

Table II

Dyeing Recipes

Chemicals	0.1% Depth	1.0% Depth	3.0% Depth
Dye (%owf)	0.1	1.0	3.0
Glauber's salt (g/L)	20	40	60
Soda ash (g/L)	5	10	15

CIE L*, a*, b*, C*, h, and ΔE* values were calculated to evaluate fabric color properties. In addition, the color yield, expressed as K/S values, from 400 nm to 700 nm in 10 nm intervals within the visible spectrum, was calculated by Eq. 1. The higher the K/S value, the greater the dye uptake, resulting in better color yield. ¹⁴

$$\frac{K}{S}=\frac{{\left(1-R\right)}^2}{2R}$$

(Eq. 1)

K is the absorption coefficient (dependent on colorant concentration), S is the scattering coefficient, and R is the reflectance of the dyed sample.

Scanning Electron Microscopy

Surface morphology of the treated samples was investigated by scanning electron microscopy (SEM) using a Leica Ste-reoscan 440 with a resolution of 3 nm at 40 k V, and with a magnification of 5000.

Results and Discussion

Color Properties

To study the effect of plasma treatment on fabric color properties, the L*, a*, b*, C*, h and ΔE values were studied. L* is the lightness value, which ranges from 0% for very dark to 100% for perfect white. a* or b* values have no limit and the actual values vary in both positive and negative territories. For achromatic colors, such as white, gray, and black, a* = b* = 0. If a* > 0, the colors possess the attribute of redness. If a* < 0, the colors possess the attribute of greenness. If b* > 0, the colors possess the attribute of yellowness. If b* < 0, the colors possess the attribute of blueness. C* stands for the chroma value, which represents the distance from the original (a* = 0, b* = 0) to the particular color. The higher the value, the greater the saturation. h stands for the hue value, the angle from 0° to 360°. ΔE refers to the color difference. If ΔE = 1.0, the color difference can be estimated. Tables III–V show the color properties of the dyed regenerated bamboo/ cotton fabrics.

Table III

Color Properties of Test Fabrics Dyed with 0.1% Reactive Dye

Treatment Condition	0.1% Mono-Functional Reactive Dye (Blue)						0.1% Bi-Functional Reactive Dye (Black)
	L*	a*	b*	C*	h	∆E	L*	a*	b*	C*	h	∆E
No Plasma (Control)	73.79	–5.41	–16.16	17.05	251.50	0.19	62.29	–6.34	–12.71	14.20	243.49	0.17
1	74.26	–5.35	–15.49	16.39	250.97	1.02	63.54	–6.12	–12.00	13.47	242.97	1.35
2	74.11	–5.39	–15.77	16.67	251.12	0.71	64.03	–5.91	–11.69	13.10	243.17	1.96
3	73.90	–5.38	–15.57	16.48	250.93	0.80	63.61	–6.46	–10.24	12.11	237.70	2.80
4	74.90	–5.20	–14.60	15.50	250.38	2.11	63.22	–6.22	–12.24	13.73	243.08	0.93
5	74.00	–5.35	–15.68	16.57	251.18	0.74	63.00	–6.48	–11.32	13.05	240.21	1.50
6	73.89	–5.27	–16.25	17.09	252.03	0.34	63.90	–6.00	–11.79	13.23	243.02	1.77
7	74.32	–5.34	–15.28	16.19	250.71	1.23	62.66	–6.15	–12.07	13.55	243.01	0.73
8	74.72	–5.37	–14.77	15.72	250.03	1.86	63.66	–6.20	–12.16	13.65	242.99	1.35
9	73.72	–5.60	–15.61	16.59	250.26	0.85	63.90	–5.93	–11.80	13.21	243.31	1.79
10	73.45	–5.37	–16.34	17.20	251.81	0.64	63.74	–6.23	–12.14	13.64	242.82	1.35
11	74.78	–5.27	–14.85	15.76	250.45	1.82	63.75	–6.15	–11.89	13.39	242.67	1.96
12	73.61	–5.33	–15.94	16.81	251.50	0.59	63.76	–6.32	–12.17	13.71	242.56	2.80
13	73.39	–5.42	–16.44	17.32	251.76	0.54	63.51	–6.28	–12.15	13.67	242.66	0.93
14	75.98	–5.18	–13.86	14.80	249.52	3.34	64.17	–6.26	–12.14	13.66	242.74	1.50
15	74.11	–5.31	–15.34	16.23	250.92	1.09	63.88	–6.22	–12.07	13.58	242.76	1.77
16	74.24	–5.43	–15.93	16.83	251.17	0.66	61.99	–6.53	–12.65	14.24	242.69	0.73
17	74.35	–5.29	–15.51	16.39	251.16	1.03	65.55	–5.86	–11.41	12.82	242.82	3.41
18	73.87	–5.42	–15.57	16.48	250.78	0.80	64.73	–5.94	–11.52	12.96	242.72	2.61
19	74.78	–5.23	–15.49	16.35	251.35	1.21	62.77	–6.34	–12.44	13.96	242.97	0.46
20	73.40	–5.39	–16.46	17.32	251.86	0.75	63.04	–6.03	–12.01	13.44	243.35	1.01
21	74.36	–5.20	–15.18	16.04	251.07	1.35	63.51	–6.05	–11.99	13.43	243.24	1.33
22	73.96	–5.30	–15.81	16.68	251.46	0.59	63.52	–6.02	–11.80	13.25	242.98	1.46
23	75.24	–5.19	–14.35	15.26	250.12	2.50	64.34	–6.11	–11.89	13.37	242.81	2.09
24	74.31	–5.28	–15.07	15.97	250.67	1.42	62.87	–6.42	–11.87	13.49	241.61	0.94
25	73.69	–5.34	–16.35	17.20	251.92	0.64	62.70	–6.04	–12.10	13.52	243.46	0.78
26	73.96	–5.27	–15.86	16.71	251.62	0.56	62.47	–6.28	–12.44	13.93	243.22	0.45
27	73.87	–5.28	–15.99	16.84	251.72	0.69	62.84	–6.16	–12.16	13.63	243.13	0.74

Table IV

Color Properties of Test Fabrics Dyed with 1.0% Reactive Dye

Treatment Condition	1.0% Mono-Functional Reactive Dye (Blue)						1.0% Bi-Functional Reactive Dye (Black)
	L*	a*	b*	C*	h	∆E	L*	a*	b*	C*	h	∆E
No Plasma (Control)	64.32	–5.47	–26.05	26.62	258.14	0.32	33.66	–6.20	–17.63	18.69	250.63	0.79
1	64.60	–5.36	–25.63	26.19	258.18	1.11	35.63	–6.53	–17.47	18.65	249.49	1.41
2	65.14	–5.39	–24.81	25.39	257.73	1.25	42.48	–6.66	–17.54	18.76	249.21	8.16
3	63.99	–5.43	–25.95	26.51	258.17	0.95	33.68	–6.32	–17.79	18.88	250.45	0.79
4	64.79	–5.35	–25.22	25.78	258.03	0.91	36.61	–6.68	–17.78	19.00	249.42	2.31
5	63.92	–5.38	–26.03	26.58	258.33	0.70	34.61	–6.42	–17.55	18.69	249.90	0.76
6	64.03	–5.24	–25.63	26.16	258.44	1.14	31.28	–5.74	–17.12	18.06	251.44	3.28
7	64.46	–5.33	–24.95	25.51	257.95	1.07	32.44	–6.17	–17.22	18.30	250.28	2.06
8	64.82	–5.21	–24.99	25.53	258.23	1.03	35.67	–6.56	–17.71	18.88	249.68	1.39
9	64.31	–5.42	–25.36	25.93	257.95	0.76	33.52	–6.13	–17.60	18.64	250.81	2.39
10	64.64	–5.61	–25.46	26.07	257.58	0.47	35.12	–6.48	–17.67	18.82	249.87	0.95
11	65.09	–5.75	–24.99	25.64	257.04	1.17	34.27	–5.92	–17.76	18.72	251.57	0.57
12	64.77	–5.77	–24.99	25.64	256.99	1.02	35.06	–6.29	–17.52	18.61	250.25	0.90
13	63.73	–5.71	–26.41	27.02	257.81	1.02	34.58	–6.27	–17.33	18.42	250.12	0.92
14	65.64	–5.82	–24.92	25.59	256.85	1.47	34.97	–6.31	–17.04	18.17	249.67	1.19
15	65.90	–5.64	–23.89	24.55	256.71	2.42	34.58	–6.07	–17.33	18.36	250.68	1.45
16	64.10	–5.93	–25.86	26.53	257.09	0.66	37.07	–6.42	–17.22	18.37	249.54	2.84
17	64.07	–5.87	–25.54	26.21	257.07	0.83	34.75	–6.17	–16.95	18.04	249.99	1.28
18	63.96	–5.77	–25.71	26.35	257.35	0.64	35.98	–6.31	–17.08	18.20	249.73	1.88
19	65.93	–5.77	–24.42	25.09	256.70	2.05	34.21	–6.41	–18.00	19.11	250.40	0.24
20	64.84	–5.55	–24.83	25.44	257.40	1.18	35.46	–6.51	–17.89	19.04	250.00	1.51
21	65.86	–5.88	–23.42	24.14	255.91	2.82	32.34	–6.08	–17.69	18.70	251.04	2.04
22	64.28	–5.86	–25.33	25.99	256.98	0.68	33.52	–6.23	–17.72	18.78	250.61	0.92
23	64.13	–5.60	–25.97	26.56	257.82	1.17	34.39	–6.54	–17.98	18.97	250.01	1.78
24	63.14	–5.61	–25.81	26.41	257.73	1.47	36.11	–6.45	–17.84	19.14	250.12	0.41
25	64.38	–5.68	–25.51	26.13	257.45	1.03	35.02	–6.39	–17.55	18.68	249.99	1.33
26	64.63	–5.62	–25.14	25.76	257.40	1.08	33.70	–6.09	–17.21	18.72	250.51	1.17
27	64.52	–5.41	–25.20	25.78	257.86	2.05	34.38	–6.31	–17.63	18.26	250.30	0.41

Table V

Color Properties of Test Fabrics Dyed with 3.0% Reactive Dye

Treatment Condition	3.0% Mono-Functional Reactive Dye (Blue)						3.0% Bi-Functional Reactive Dye (Black)
	L*	a*	b*	C*	h	∆E	L*	a*	b*	C*	h	∆E
No Plasma (Control)	52.74	–4.14	–34.41	34.65	263.14	0.32	21.83	–2.76	–13.01	13.30	258.05	1.29
1	53.28	–4.15	–34.69	34.94	263.17	0.89	21.23	–2.62	–12.45	12.73	258.14	2.13
2	53.29	–4.09	–34.91	35.15	263.31	0.74	22.66	–2.89	–13.00	13.32	257.46	0.93
3	51.46	–3.62	–35.75	35.93	264.22	2.02	22.90	–2.90	–12.79	13.11	257.25	1.38
4	51.36	–3.55	–36.44	36.62	264.43	2.61	21.18	–2.40	–12.41	12.64	259.11	2.24
5	51.66	–3.65	–35.87	36.06	264.19	2.02	21.39	–2.52	–12.35	12.61	258.47	2.15
6	52.53	–3.90	–35.57	35.79	263.74	1.51	22.61	–3.01	–13.30	13.64	257.24	0.63
7	53.09	–3.95	–34.73	34.96	263.50	1.37	21.73	–2.70	–12.69	12.97	258.01	1.64
8	52.57	–3.80	–35.43	35.63	263.87	1.31	21.76	–2.72	–12.84	13.13	258.04	1.46
9	53.62	–4.23	–34.60	34.86	263.02	1.30	20.27	–2.23	–12.11	12.32	259.58	3.16
10	49.56	–3.06	–37.95	38.07	265.38	3.39	20.71	–2.50	–12.50	12.74	258.71	2.53
11	49.93	–3.16	–37.44	37.58	265.18	4.36	21.37	–2.58	–12.81	13.07	258.61	1.81
12	47.25	–2.21	–39.26	39.32	266.77	7.67	20.84	–2.53	–12.63	12.88	258.66	2.34
13	50.40	–3.31	–36.52	36.67	264.82	3.37	21.95	–2.84	–13.02	13.33	257.72	1.19
14	51.32	–3.54	–36.13	36.31	264.40	2.41	21.65	–2.65	–12.81	13.09	258.30	1.61
15	49.04	–2.94	–37.71	37.82	265.54	5.20	21.51	–2.67	–12.58	12.86	258.01	1.85
16	52.33	–3.97	–36.34	36.56	263.76	2.05	21.29	–2.65	–12.80	13.07	258.34	1.86
17	48.79	–2.59	–38.03	38.12	266.09	5.67	21.36	–2.71	–12.62	12.91	257.91	1.93
18	52.70	–4.04	–36.39	36.61	263.67	1.98	20.82	–2.53	–12.56	12.81	258.62	2.40
19	54.50	–4.56	–33.01	33.32	262.13	2.25	22.10	–2.80	–13.42	13.71	258.21	0.83
20	51.75	–3.92	–35.88	36.10	263.77	1.87	23.39	–3.08	–13.62	13.96	257.25	1.13
21	53.39	–4.16	–34.47	34.73	263.12	0.54	22.04	–2.64	–12.75	13.02	258.36	2.14
22	52.37	–4.04	–34.99	35.23	263.42	0.82	21.42	–2.29	–12.15	12.37	259.41	2.30
23	52.07	–3.88	–34.92	35.13	263.67	1.04	20.62	–2.44	–12.20	12.44	258.69	2.80
24	52.67	–3.95	–34.79	35.01	263.53	0.78	21.12	–2.62	–13.06	13.32	258.66	1.88
25	53.24	–4.15	–34.18	34.43	263.08	0.80	20.66	–2.43	–12.52	12.76	259.03	2.58
26	53.15	–4.03	–33.83	34.07	263.21	1.00	21.35	–2.75	–12.97	13.25	258.03	1.70
27	53.91	–4.22	–33.72	33.98	262.86	1.30	21.15	–2.58	–12.24	12.51	258.19	2.52

For plasma-treated fabric dyed with mono-functional reactive dye to 0.1% and 1% depth, the control fabrics (fabrics without plasma treatment) showed high L* values of 73.8% and 64.3%, respectively. For fabrics treated with plasma and dyed with bi-functional reactive dye to 0.1% and 1% depth, the control fabrics showed medium L* values, 62.3% and 33.7%, respectively. Most of the plasma-treated fabrics subjected to 0.1% and 1% depth dyeing had L* values similar to their respective control fabric. Also, the control fabrics showed negative a* values, which meant the fabric color possessed the attribute of greenness. Compared with the control fabric, some of the plasma-treated fabrics gave less negative a* values, indicating that the color of the plasma-treated fabric had a little greater redness. From the b* value results, the control fabrics showed negative b* values, indicating that the color of the control fabric possessed blueness. However, some of the plasma-treated fabrics showed a little less negative b* value. In other words, the plasma-treated fabrics had greater yellowness. This may be due to overheating of plasma-treated fabric during plasma treatment.^15,16 About half of the plasma-treated fabrics gave ΔE values of greater than 1.0 (i.e., the plasma treatment induced significant color difference). However, h values changed very little. Therefore, it was concluded that the plasma treatment did not alter the shade of the dyed fabric, but did affect the color depth.

Plasma-treated fabrics dyed with 3.0% mono-functional reactive dye possessed less lightness, greater redness, and greater blueness than their corresponding 0.1% and 1.0% dyeings. Plasma treatment resulted in significant improvement in dye absorption at relatively higher concentration (i.e., L* values decreased). Since the mono-functional reactive dye was blue, more of the blue dye was absorbed on the fabric, which overcame the yellowing problem introduced by plasma treatment (i.e., b* values decreased).

Plasma-treated fabrics dyed with 3.0% bi-functional reactive dyes possessed less lightness, greater redness, and greater yellowness than their corresponding 0.1% and 1.0% dyeings. The results further confirm that plasma treatment gave significant improvement in dye absorption at relatively higher concentrations (i.e., L* values decreased). Also, this plasma-treated fabric possessed greater yellowness due to the overheating of plasma-treated fabric during plasma treatment (i.e., b* values increased). ¹⁷

For the 3% depth dyeing, similar to the 0.1% and 1.0% depth results, the ΔE values of plasma-treated fabrics were greater than 1, but the h values changed little. This reinforces the earlier conclusion that the plasma treatment did not alter the shade of the dyed fabric, but did affect the color depth.

K/S Values

K/S values were also used as the color measure for evaluating the dyeability of the treated regenerated bamboo/cotton fabrics (Table VI).

Table VI

K/S Values of Dyed Cotton/Regenerated Bamboo Fabrics

Treatment Condition	K/S Values of Fabrics Dyed with
	0.1% Mono-functional (Blue)	0.1% Bi-functional (Black)	1% Mono-functional (Blue)	1% Bi-functional (Black)	3% Mono-functional (Blue)	3% Bi-functional (Black)
No Plasma (Control)	8.70	20.76	19.64	153.49	48.63	366.33
1	8.34	18.92	19.12	132.96	46.94	383.83
2	8.46	18.23	18.24	81.55	46.95	340.58
3	8.63	19.04	20.08	153.71	53.67	333.55
4	7.84	19.38	20.69	124.14	53.67	385.05
5	8.55	19.80	20.18	143.27	52.93	376.85
6	8.63	18.42	19.91	181.83	49.46	342.94
7	8.29	20.20	19.14	167.71	47.44	368.20
8	7.99	18.74	18.65	132.98	49.44	366.58
9	8.80	18.40	19.46	157.13	45.97	414.73
10	8.97	18.98	19.17	138.22	62.93	400.83
11	7.93	18.08	18.54	145.70	60.96	380.36
12	8.85	18.46	18.94	138.07	75.31	396.10
13	9.03	21.25	20.69	142.80	58.32	362.09
14	7.06	16.26	17.77	138.82	54.33	369.85
15	8.44	17.32	17.26	143.04	65.17	374.18
16	8.34	17.77	20.07	160.88	51.02	382.24
17	8.25	18.64	20.04	140.49	66.20	380.29
18	8.64	18.63	20.24	128.70	49.73	396.67
19	8.09	20.05	17.34	148.05	42.42	357.40
20	9.02	19.65	18.84	135.58	53.10	322.17
21	8.23	18.95	17.37	169.53	46.45	361.58
22	8.55	18.97	19.77	155.13	50.21	375.16
23	7.57	17.83	20.03	129.11	51.14	402.48
24	8.28	19.97	21.50	146.18	49.02	387.84
25	8.77	20.12	19.60	139.37	46.81	401.80
26	8.54	20.50	19.16	152.28	46.80	380.36
27	8.63	19.93	19.41	145.46	44.55	389.99

When the fabrics were dyed with 0.1% or 1% reactive dyes, it was found that all plasma-treated fabrics had about the same K/S values as the untreated fabrics (Table VI). There were no significant differences among K/S values of fabrics plasma-treated at different oxygen flow rates, times, and treatment distances. The small variations among K/S values of the plasma-treated fabrics may be due to uneven dyeing. However, when the fabrics were dyed with 3% reactive dye, most of the plasma-treated fabrics had higher K/S values than the control fabric, implying that the concentration of colorant in the substrate medium increased. The results confirmed that plasma treatment significantly improves dyed absorption at relatively higher concentrations.

SEM Analysis

Fig. 2a shows that the untreated regenerated bamboo fiber had a smooth surface. After plasma treatment, the regenerated bamboo fiber surface (Fig. 2b) became rough and cracks formed along the fiber axis. These cracks may provide new pathway for the dye to enter the fiber and hence increase the color yield.^10,11

Fig. 2

(a) untreated regenerated bamboo, (b) plasma treated regenerated bamboo (oxygen flow rate = 0.5 L/min; treatment time = 0.1 s, jet-to-substrate distance = 5 mm).

Conclusion

In this research, low temperature plasma treatment was imparted to regenerated bamboo/cotton blended fabric under different parameters including oxygen flow rate, jet-to-substrate distance, and treatment time. Effects of plasma-treatment on dyeability were examined with two different reactive dyes and the results confirmed that plasma treatment caused no significant enhancement of color yield in low concentration dyeing. The results also confirm that dye uptake increased only when dyeing was at 3% depth. However, plasma treatment did not alter the shade of the dyed fabric, but affected the color depth.

A study of the wettability of regenerated bamboo/cotton blended fabric is in press. ¹⁸ Future work will focus on the systematic study of plasma treatment variables influencing the dyeability of regenerated bamboo/cotton blended fabrics.