Synthesis and application of an alkaline crosslinking agent containing acrylamide as the durable press finishing agent on cotton fabric

Abstract

In this study, acrylamide-containing crosslinking agents 2,4-diacrylamidebenzenesulfonic acid (AC-DABS1) and 2,5-diacrylamidebenzenesulfonic acid (AC-DABS2) were synthesized and applied to cotton fabric as durable press finishing agents under alkaline conditions. The target products were characterized by high-performance liquid chromatography (HPLC) and proton nuclear magnetic resonance. The stability of the acrylamide group in alkaline solution was investigated by model compound para-acrylamidebenzenesulfonic acid. The efficiency of AC-DABS1 and AC-DABS2 as durable press finishing agents was examined and compared by testing the wrinkle recovery angle (WRA), tearing strength retention (TSR) and washing durability under different conditions using the steaming process. The performance of fabric treated with 1,3,5-triacroylaminohexahydro-s-triazine (FAP) was also investigated and compared with those treated with acrylamide-containing crosslinking agents. The results showed that the anti-crease effects of FAP were better than those of the new synthesized agents. However, the new synthesized agents have the advantage of water solubility and low cost. The fabric treated with new synthesized agents presented satisfactory WRA and TSR, indicating that AC-DABS1 and AC-DABS2 can be utilized as effective alkaline crosslinking agents. In addition, the different performance of the FAP-treated fabric and fabric treated with the new synthesized agents was illustrated by the HPLC method.

Keywords

alkaline crosslinking agent steaming process durable press finishing wrinkle recovery angle tearing strength retention

Cotton fabric is an essential apparel material because of its excellent properties, such as air permeability, sweat absorption and being comfortable to wear. Unfortunately, cotton fabric wrinkles easily during wearing and home laundering.^1–3 To produce wrinkle-free cotton fabrics, crosslinking agents, which can form a crosslinkage among cellulosic chains, are usually utilized.

There are mainly two types of crosslinking agents in the area of textiles: formaldehyde-based agents and formaldehyde-free agents. For the former, formaldehyde-based N-methylol reagents are the most general anti-crease finishing agents, such as dimethylol dihydroxy ethylene urea (DMDHEU) and its modified versions of “low-formaldehyde”.² Formaldehyde-based N-methylol reagents can react with the hydroxyl of celluloses to create a covalent crosslink under acidic condition. However, cotton fabric treated with these agents can release formaldehyde during the finishing process and wearing.^4,5 The releasing formaldehyde is a skin irritant and has a bad odor, which has an adverse impact on human health and the environment.^6–10

Hence, extensive efforts have been made to develop formaldehyde-free crosslinking agents,^8,11–19 where polycarboxylic acids, such as tetracarboxylic acid (BTCA), citric acid and maleic acid, are recognized as the most promising alternatives.^20–24

However, another critical issue is associated with the above two types of crosslinking agents, in that severe tensile strength loss may take place due to depolymerization of cellulose macromolecules in the acid condition or the catalyst.^25–27 For example, the Lewis acid catalyst, such as magnesium chloride, is indispensable for employment of the traditional N-methylol reagents at curing temperatures as high as 160℃. Polycarboxylic acid is much more acidic. The curing temperature is higher (170–180℃), resulting in more severe degradation of cellulose and much lower tensile strength of cotton fabric than for formaldehyde-based agents.²⁸

To reduce the mechanical strength loss of cotton fabric treated with a durable press finishing agent, FAP, whose chemical name is 1,3,5-triacroylaminohexahydro-s-triazine (Figure 1), has been used as a durable press finishing agent under alkaline condition, but its disadvantage of low solubility in cold water has restricted its general application.¹¹ Inspired by the structure of FAP, we attempted to develop novel durable press finishing agents containing the sulfonic acid group(-SO₃H), with the aim to increase its solubility in water and the acrylamide group, which can react with the hydroxyl group of cellulose.²⁹

Figure 1.

Structure of 1,3,5-triacroylaminohexahydro-s-triazine (FAP).

In this paper, two acrylamide-containing crosslinking agents that can be utilized in alkaline conditions were successfully synthesized, 2,4-diacrylamidebenzenesulfonic acid (AC-DABS1) and 2,5-diacrylamidebenzenesulfonic acid (AC-DABS2) (shown in Figure 2), whose chemical structures were characterized by high-performance liquid chromatography (HPLC) and proton nuclear magnetic resonance (¹HNMR). More importantly, their application as crosslinking agents for cotton fabric has been investigated and the performance was compared with that of FAP. Also, we synthesized model compound para-acrylamidebenzenesulfonic acid (AC-PABS) (in Figure 2) to investigate the stability of the acrylamide group in different alkaline conditions, as well as to illustrate the various performances of the two acrylamide crosslinking agents and FAP.

Figure 2.

Synthesis route. DABS1: 2,4-diaminobenzenesulfonic acid; DABS2: 2,5-diaminobenzenesulfonic acid; PABS: p-aminobenzenesulfonic acid; AC-DABS1: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid; AC-DABS2: acrylamide-containing 2,5-diacrylamidebenzenesulfonic acid; AC-PABS: acrylamide-containing para-acrylamidebenzenesulfonic acid.

Experimental details

Materials and chemicals

Woven cotton fabric, which was desized, scoured, bleached and whitened by a fluorescent brightening agent, was used throughout this work. The wrinkle recovery angle (WRA) and whiteness index (WI) of the untreated fabric were 153° and 121.6, respectively.

FAP was purchased from TCI Development Co., Ltd (Tokyo, Japan). p-aminobenzenesulfonic acid (PABS), acryloyl chloride (AC), tetrabutylammonium bromide (TBAB), 2,4-diaminobenzenesulfonic acid (DABS1) and 2,5-diaminobenzenesulfonic acid (DABS2) were purchased from Energy Chemical Reagent Co., Ltd. Sodium bicarbonate, sodium carbonate, sodium hydroxide, sodium chloride, anhydrous diethyl ether, hydrochloric acid and sodium dihydrogen phosphate were laboratory-grade chemicals.

Synthesis

Synthesis of AC-DABS1

The synthesis route of AC-DABS1 is shown in Figure 2(a). A solution of AC (0.25 mol, 20.3 mL) in ether (50 mL) was slowly added dropwise to the well stirred aqueous solution of the sodium salt of 2,4-diaminobenzenesulfonic acid (0.1 mol), which was cooled to 0–5℃. The pH of the reacting mixture was maintained between 3 and 5 by adding sodium carbonate solution. After the addition of AC, the solution was acidified with concentrated HCl. Then sodium chloride was added to salt out the product. After filtering and drying, the pure product was collected with 80% yield.

HPLC: water/acetonitrile (V/V) was 60:40. There was a new peak at retention time 7.4 min that ascribed to the product.

¹HNMR (400 MHz, D₂O): δ (ppm) 8.15 (s, 1H, ArH), 7.69 (s, 1H, ArH), 7.31 (s, 1H, ArH), 6.25 (m, 4H, =CH₂), 5.78 (m, 1H, -CH=).

Synthesis of AC-DABS2

The procedure of synthesis AC-DABS2 was the same as for AC-DABS1, except DABS2 was used (shown in Figure 2(b)). The yield of AC-DABS2 is 78%. Under the same HPLC analysis condition, the retention time of AC-DABS2 is 7.1 min.

¹HNMR (400 MHz, D₂O): δ (ppm) 8.42 (s, 1H, ArH), 7.67 (d, 1H, ArH), 7.30 (dd, 1H, ArH), 6.37 (m, 2H, =CH₂), 6.24 (d, 2H, =CH₂), 6.20 (d, 1H, -CH=), 5.86 (dd, 1H, -CH=).

Synthesis of AC-PABS

A total of 34.6 g of PABS (0.2 mol) was dissolved in water (100 mL) containing 4.0 g of sodium hydroxide. The solution was cooled to 0–5℃ and 20 mL of AC dissolved in ethylether (50 mL) was added dropwise. Sodium carbonate solution was added to maintain the reaction mixture at a pH of 3–5. After finishing the adding, concentrated HCl was added to acidify the solution. Then, sodium chloride was added to salt out the product. After filtering and drying, pure product was collected with 65% yield.

HPLC: water/acetonitrile (V/V) was 75:25. Retention time was 8.37 min.

¹HNMR (400 MHz, D₂O): δ (ppm), 7.54 (dt, 4H, ArH), 6.24 (m, 2H, =CH₂), 5.72 (d, 1H, -CH=).

Durable press finishing of cotton fabric

AC-DABS1 and AC-DABS2 finishing: the treating solution was prepared by mixing AC-DABS1 or AC-DABS2 with sodium carbonate to a specified concentration. Cotton fabric was immersed in the finishing solution using the two dips and two nips method and then dried at 80℃ for 3 min throughout the finishing treatment.

FAP finishing: FAP was mixed with water at 70℃ with stirring, while diluted ammonia solution (the mole ratio of FAP to NH₃ was 4:1) was added quickly. Stirring was continued until a clear solution was formed. Cotton fabric was padded with the solution by two dips and two nips, where the nip pressure was set to give a pickup of 100%. Then the cotton was dried at 80℃ for 3 min and then steamed at a specified temperature and moisture content for a specified time.

Characterization and measurement

HPLC

HPLC analysis was performed on an Agilent 1200 system equipped with a column (SUPELCOSIL LC-18, 25 cm × 4.6 mm, 5 µm) and an ultraviolet (UV) variable wavelength detector (VWD). HPLC analysis was operated with a mobile phase water/acetonitrile (v/v) at a flow rate of 1.0 mL/min, wavelength of 254 nm and column temperature of 30℃. The water phase was a mixture of TBAB and dihydrogen phosphate solution.

¹HNMR

¹HNMR spectra were recorded at 298 K on a Bruker ARX 400 spectrometer (at 400.13 MHz) and chemical shifts were internally referenced to Me₄Si (0 ppm).

Measurements of WRA, tearing strength retention and WI

Samples were conditioned for at least 4 h at 65 ± 2% relative humidity and 20 ± 1℃. The WRA was tested according to AATCC Testing Method 66-2003 on an SDL Atlas M003A tester. Tearing strength was measured according to the ASTM D1424-2009 standard by a Thwing-Albert-Elmendorf tearing machine and tearing strength retention (TSR%) was calculated using the untreated sample as a control, as shown in Equation (1). All measurements of tearing strength were carried out in the weft direction

TSR % = \frac{T}{T_{0}} \times 100 %

(1)

where T is the strength of the treated sample, cN, and T₀ is the strength of the untreated sample, cN.

The WI was determined according to AATCC Testing Method 11-2005 using a Datacolor 650 Bench-Top Spectrophotometer. Standard washing was tested as per the AATCC Test Method 124-2001. All measurements were tested after one washing circle. Durable press (DP) rating was tested as per the AATCC Test Method 124-1996.

Investigating the stability of the acrylamide group in the alkaline condition

In sodium bicarbonate solution: 1.14 g of AC-PABS and 2.0 g of sodium bicarbonate were dissolved in 50 mL water and the reaction mixture was set at 80℃.

In sodium carbonate solution: 1.14 g of AC-PABS and 2.0 g of sodium carbonate were dissolved in 50 mL water and the reaction mixture was set at 80℃.

In sodium hydroxide solution: 1.14 g of AC-PABS was dissolved in 50 mL water. After increasing the temperature to 80℃, 1.2 g of sodium hydroxide was added.

The content of AC-PABS in the alkaline condition was calculated as per Equation (2)

ContentofAC - PABS = \frac{A}{A_{0}} \times 100 %

(2)

where A₀ is the peak area of AC-PABS in the HPLC result at time = 0 and A is the peak area of AC-PABS at the specified time.

Investigating the reactivity of the acrylamide group with cellulose

After impregnating into a solution of AC-PABS and sodium carbonate, two pieces of cotton fabric were dried at 80℃ for 3 min. Then, one piece of the cotton fabric was treated in steaming conditions at different temperatures for a specific time.

Both pieces of cotton fabric were analyzed by HPLC (water/acetonitrile (75/25), 254 nm, 30℃, 1 mL/min) and the content of AC-PABS grafted onto cotton treated by the steaming process can be obtained by Equation (3)

Graftingratio = \frac{A_{0} - A}{A_{0}} \times 100 %

(3)

where A₀ is the area of the AC-PABS peak on the drying cotton and A is the sum of the area of the peaks of different compounds on the cotton sample treated by the steaming process.

Results and discussion

Stability of the acrylamide group in the alkaline condition

In order to develop crosslinking agents suitable for the alkaline condition with a similar structure to FAP, our first task is to investigate the stability of the acrylamide group in the alkaline condition. Therefore, we synthesized model compound AC-PABS. Figure 3 shows the changing content of AC-PABS in different alkaline solutions. It was clear that AC-PABS was very stable in sodium bicarbonate solution and the content of AC-PABS decreased at different levels in sodium carbonate solution and sodium hydroxide solution, which could be ascribed to the different alkalinity of sodium carbonate and sodium hydroxide.

Figure 3.

Acrylamide-containing para-acrylamidebenzenesulfonic acid (AC-PABS) content under different alkaline conditions.

HPLC analysis of AC-PABS under the alkaline condition revealed that AC-PABS (retention time 8.37 min) was hydrolyzed to PABS (retention time 5.66 min) and compound AC-PABSOH (retention time 5.31 min, the structure is shown in Figure 10). In Figure 4, the changing percentage of AC-PABS, PABS and AC-PABSOH in alkaline solution is shown. It is clear that the concentration change of compounds in sodium hydroxide solution is more drastic than in sodium carbonate solution and the rate of generating compound AC-PABSOH is faster than making PABS in both sodium hydroxide and sodium carbonate media.

Figure 4.

Variation of acrylamide-containing para-acrylamidebenzenesulfonic acid (AC-PABS), p-aminobenzenesulfonic acid (PABS) and compound AC-PABSOH concentration in sodium carbonate (a) and sodium hydroxide (b) in the hydrolysis process.

Based on the analysis above, to avoid hydrolyzing of the acrylamide group, we choose sodium carbonate as the alkaline in our study.

Efficiency of durable press finishing by the steaming and curing process

In this study, the efficiency of durable press finishing by the steaming and curing process was compared and the results are shown in Table 1. The fabric was impregnated with 80 g/L of AC-DABS1 and 20 g/L of sodium carbonate solution, then dried at 80℃ for 3 min. The steaming process was carried out at 110℃ with 75% relative humidity for 5 min; the curing process was carried out at 160℃ for 3 min.

Table 1.

Comparison of the steaming process with the curing process

Method	WRA/°	TSR/%	Whiteness index
Untreated fabric	153	100	121.6
Steaming	227	87.6	106.9
Curing	192	70.2	86.3

WRA: wrinkle recovery angle; TSR: tearing strength retention.

It can be seen from Table 1 that the WRA, TSR and whiteness of fabric treated with the steaming process was better than that of the curing process. In addition to the good performance of the cotton fabric, the steaming process is an energy-efficient process. So, we choose steaming process as the research object.

Factors influencing the performance of cotton fabric treated with AC-DABS1

To investigate the utilization of AC-DABS1 as a durable press finishing agent for cotton fabric under the alkaline condition, we explored the factors influencing the performance of cotton fabric treated with AC-DABS1, such as AC-DABS1 concentration, sodium carbonate concentration, steaming temperature, steaming humidity and steaming time.

The influence of AC-DABS1 concentration on the performance of the cotton fabric under the steaming process was investigated. The results are shown in Table 2. It can be seen from Table 2 that the WRA increased naturally after AC-DABS1 treatment. The WRA increased as the concentration of the crosslinking agent increasing. When the concentration increased to 80 g/L, the WRA was increased to its maximum value and further increasing the AC-DABS1 concentration had little effect on the WRA. The possible reason for this is that more crosslinking reactions may occur when the high AC-DABS1 concentration was used. However, the WRA will not increase as the crosslinking increases all the time. On increasing the AC-DABS1 concentration, both the whiteness and TSR of cotton fabric decreased to some extent. Taking the above into consideration, we chose 80 g/L as the concentration in the later experiment.

Table 2.

Effect of acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid concentration on the performance of fabric

Concentration	WRA (°)			Whiteness	TSR/%
Concentration	Warp	Weft	Warp+Weft	Whiteness	TSR/%
Untreated fabric	75	78	153	121.6	100
60	104	107	211	109.1	91.4
70	109	110	219	108.5	88.5
80	112	115	227	107.5	87.6
90	113	116	229	106.9	84.9
100	114	116	230	106.7	84.3

Note: condition: 20 g/L of sodium carbonate, steaming temperature at 110℃ with 75% relative humidity for 5 min.

WRA: wrinkle recovery angle; TSR: tearing strength retention.

It can be seen from Table 3 that alkaline played an essential role in the crosslinking finishing process. Sodium carbonate can accelerate the hydroxyl of cellulose to become an anionic state, which promotes the crosslinking reaction rate. The WRA could increase from 155° to 223° after adding 5 g/L of sodium carbonate in the finishing formulation. Sodium carbonate concentration higher than 10 g/L had little contribution to the WRA, which might be because 10 g/L of alkaline could provide enough alkalinity for making the crosslinking reaction happen. Both the whiteness and TSR decreased slightly on increasing the alkaline concentration. Here, we chose 10 g/L sodium carbonate for the experiment.

Table 3.

Effect of sodium carbonate concentration on the performance of fabric

Alkaline concentration/L	WRA (°)			Whiteness	TSR/%
Alkaline concentration/L	Warp	Weft	Warp+Weft	Whiteness	TSR/%
untreated	75	78	153	121.6	100
0	76	79	155	117.4	96
5	109	114	223	110.8	88.3
10	112	114	226	108.4	86.7
15	113	114	227	107.5	84.7
20	112	115	227	106.9	84.6
25	112	112	224	104.1	83.6

Note: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid 80 g/L, steaming at 110℃ with 75% humidity for 5 min.

WRA: wrinkle recovery angle; TSR: tearing strength retention.

The effect of steaming temperature on the performance of fabric is shown in Table 4. As shown in Table 4, steaming at 90℃ can improve the WRA from 153° to 204°, which means the crosslinking reaction could occur at a low temperature. On increasing the steaming temperature, the WRA increased prominently. At the temperature of 110℃, the WRA value reached its peak. Further increasing the steaming temperature had little effect on the WRA, which could be because the crosslinking reaction completed at 110℃. Both the whiteness and TSR decreased on increasing steaming temperature. Taking this into consideration, we chose 110℃ as the steaming temperature for further study.

Table 4.

Effect of steaming temperature on the performance of fabric

Temperature/℃	WRA (°)			Whiteness	TSR/%
Temperature/℃	Warp	Weft	Warp+Weft	Whiteness	TSR/%
Untreated	75	78	153	121.6	100
90	102	102	204	114.5	92.2
100	105	109	216	112.2	90.8
110	112	115	227	106.9	87.6
120	111	114	225	101.1	84.3
130	105	106	211	92.5	81.1

Note: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid 80 g/L, alkaline 20 g/L, steaming at specified temperature with 75% humidity for 5 min.

WRA: wrinkle recovery angle; TSR: tearing strength retention.

Steaming humidity is an important factor affecting the performance of the treated fabric. It can be seen from Table 5 that the WRA increased as the humidity increased from 55% to 75%; the WRA would not increase if the humidity were higher than 75%. The possible reason for this is that the alkaline cannot ionize efficiently in low humidity, while humidity that is too high accelerates the hydrolysis of the crosslinking agent. Increasing humidity can deteriorate both whiteness and tearing strength. Therefore, 75% humidity is a proper condition.

Table 5.

Effect of steaming humidity on the performance of the fabric

Humidity/%	WRA (°)			Whiteness	TSR/%
Humidity/%	Warp	Weft	Warp+Weft	Whiteness	TSR/%
Untreated	75	78	153	121.6	100
55	101	100	201	107.8	87.8
66	107	109	216	109.4	84.4
75	112	115	227	106.9	87.6
85	105	105	210	107.4	83.2
95	98	99	197	104.9	85.1

Note: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid 80 g/L, sodium carbonate 20 g/L, steaming at 110℃ for 5 min.

WRA: wrinkle recovery angle; TSR: tearing strength retention.

The performance of the treated fabric could be affected by steaming time (shown in Table 6). Obviously, a long steaming time can make the crosslinking reaction more efficient. However, steaming for more than 5 min has little effect on the WRA. Both whiteness and tearing strength decreased with increasing steaming time. Therefore, steaming for 5 min is suitable for this study.

Table 6.

Effect of steaming time on the performance of the fabric

Steaming time/min	WRA (°)			Whiteness	TSR/%
Steaming time/min	Warp	Weft	Warp+Weft	Whiteness	TSR/%
Untreated	75	78	153	121.6	100
2	97	99	196	113.5	93.2
3	101	103	204	111.6	90.3
4	106	110	216	109.7	88.4
5	112	115	227	106.9	87.6
6	114	114	228	104.5	85.9
7	114	113	227	103.1	83.6

Note: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid 80 g/L, sodium carbonate 20 g/L, steaming at 110℃ with 75% humidity.

WRA: wrinkle recovery angle; TSR: tearing strength retention.

Comparison of the performance of cotton fabric treated by AC-DABS2 and AC-DABS1

Similar investigations were carried out with AC-DABS2 as the finishing agent. Here the effect of the concentration of the finishing agent, steaming temperature, steaming time and washing cycle on the WRA and TSR were compared with cotton fabric treated with AC-DABS1 (shown in Figures 5 –7). It has been shown that both AC-DABS1 and AC-DABS2 have a similar effect on the WRA and TSR, where low TSR usually accompanies higher WRA. The performance of fabric treated with AC-DABS2 presented a higher WRA than that treated with AC-DABS1, which might be ascribed to the fact that it is easier for cellulose to react with AC-DABS2 than with AC-DABS1 due to the steric hindrance effect. What is more, we tested washing durability after nine washing cycles (Figure 8). It can be seen from Figure 8 that the WRA decreased with increasing washing cycles because the crosslinking was damaged during washing. The WRA sharply reduced after one washing cycle, which might be associated with “chemical deposition”. The washing process removed the chemicals not reacting with cotton, resulting in a sharp decrease in the WRA. The DP rating was 3.0 after one washing cycle and decreased with washing more cycles. In general, the DP rating was in the range of 3.0–2.5 with increasing numbers of washing cycles from one to nine.

Figure 5.

Effect of crosslinking agent concentration on the wrinkle recovery angle (WRA) and tearing strength retention (TSR) (20 g/L sodium carbonate, steaming at 110℃ with 75% humidity for 5 min). AC-DABS1: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid; AC-DABS2: acrylamide-containing 2,5-diacrylamidebenzenesulfonic acid.

Figure 6.

Effect of steaming temperature on the wrinkle recovery angle (WRA) and tearing strength retention (TSR) (80 g/L crosslinking agents, steaming at 75% humidity for 5 min). AC-DABS1: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid; AC-DABS2: acrylamide-containing 2,5-diacrylamidebenzenesulfonic acid.

Figure 7.

Effect of steaming time on the wrinkle recovery angle (WRA) and tearing strength retention (TSR) (80 g/L crosslinking agents, steaming at 110℃ with 75% humidity). AC-DABS1: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid; AC-DABS2: acrylamide-containing 2,5-diacrylamidebenzenesulfonic acid.

Figure 8.

Washing durability (80 g/L crosslinking agents, steaming at 110℃ with 75% humidity). AC-DABS1: acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid; AC-DABS2: acrylamide-containing 2,5-diacrylamidebenzenesulfonic acid.

Comparing the crosslinking efficiency of FAP and acrylamide-containing crosslinking agents for cotton fabric

In order to compare the effectiveness of the two synthesized compounds with that of FAP, the factors affecting the performance of FAP-treated fabric were investigated and are shown in Table 7. It was seen that alkaline concentration, steaming temperature, steaming humidity and steaming time could affect the performance of the treated fabric. By analyzing the results, we can conclude that the optimum conditions of the FAP finishing process are sodium carbonate concentration of more than 5 g/L and steaming at 120℃ with 65% humidity for 4 min.

Table 7.

Factors affecting the performance of 1,3,5-triacroylaminohexahydro-s-triazine-treated cotton fabric

Sample no.	Alkaline concentration/(g/L)	Steaming temperature/℃	Steaming humidity/%	Steaming time/min	WRA/°	TSR/%	Whiteness
Untreated					153	100	121.6
A1	0	120	65	4	185	86.2	110.4
A2	5	120	65	4	243	74.3	108.3
A3	10	120	65	4	248	73.5	107.4
A4	15	120	65	4	245	72.8	106.9
A5	20	120	65	4	252	73.6	105.7
A6	25	120	65	4	246	73.0	103.2
B1	20	100	65	4	221	83.4	109.7
B2	20	110	65	4	234	78.9	105.8
B3	20	120	65	4	252	73.6	105.7
B4	20	130	65	4	231	70.2	101.3
B5	20	140	65	4	219	65.3	97.1
C1	20	120	45	4	222	81.1	107.5
C2	20	120	55	4	237	78.6	108.6
C3	20	120	65	4	252	73.6	105.7
C4	20	120	75	4	239	73.6	108.2
C5	20	120	85	4	224	75.1	105.9
D1	20	120	65	2	198	91.6	114.2
D2	20	120	65	3	237	78.4	107.3
D3	20	120	65	4	252	73.6	105.7
D4	20	120	65	5	254	70.3	100.3
D5	20	120	65	6	255	67.8	99.5

WRA: wrinkle recovery angle; TSR: tearing strength retention.

Figure 9 shows the WRA of fabric treated with FAP, AC-DABS1 and AC-DABS2. It was clear that FAP-treated fabric presented better WRA performance than that of AC-DABS1 or AC-DABS2.

Figure 9.

Wrinkle recovery angle (WRA) of fabric treated with 1,3,5-triacroylaminohexahydro-s-triazine (FAP), acrylamide- containing 2,4-diacrylamidebenzenesulfonic acid (AC-DABS1) and acrylamide-containing 2,5-diacrylamidebenzenesulfonic acid (AC-DABS2).

To illustrate this difference, AC-PABS was used to research the reactivity of the acrylamide group with cotton fabric by the HPLC method, as described in the Investigating the reactivity of the acrylamide group with cellulose section.

In the Stability of the acrylamide group in the alkaline condition section we observed that AC-PABS was converted to PABS and AC-PABSOH (structure shown in Figure 10) in alkaline conditions. It was found that PABS and PABSOH were also observed in HPLC analysis of the cotton sample treated with AC-PABS by the steaming process. We confirmed that three reactions (reactions i, ii, iii) occurred on the AC-PABS-treated cotton (Figure 10).

Figure 10.

Reactions occurring on acrylamide-containing para-acrylamidebenzenesulfonic acid (AC-PABS)-treated cotton during the steaming process.

Thus, the reactions that occurred on AC-DABS1-treated cotton were as shown in Figure 11. There are three types of reaction, namely a reaction with cellulose through the mechanism of nucleophilic addition (reaction R1), the hydrolysis of the carbon–carbon double bond (reaction R2) and the hydrolysis of the amido bond (reaction R3).

Figure 11.

Reactions that occurred on acrylamide-containing 2,4-diacrylamidebenzenesulfonic acid (AC-DABS1)-treated cotton.

Obviously, only reaction R1 contributes to crosslinking. We introduced the “grafting ratio” to estimate the crosslinking capability of AC-DABS1 indirectly. The results of the grafting ratio are shown in Table 8. It can be seen from Table 8 that the steaming time had a more prominent effect on the grafting ratio than the steaming temperature. The grafting ratio is only 58.8% after steaming at 110℃ for 6 min, which means 41.2% of the acrylamide group cannot react with cotton cellulose. Therefore, the different performance of AC-DABS1-treated fabric with FAP-treated fabric could be accounted for by the number of acrylamide groups in the structure. Because of the three acrylamide groups in FAP, the crosslinking reaction probability is higher than that for AC-DABS1, which has only two acrylamide groups.

Table 8.

Grafting ratio of the acrylamide group under different conditions (unit: %)

Steaming temperature	2 min	4 min	6 min
100℃	21.8	41.1	51.9
110℃	27.1	45.3	58.8
120℃	26.3	43.0	55.9
130℃	26.3	43.0	52.1

Note: the steaming humidity was 75%.

Conclusion

In this study, we concluded that the newly synthesized compounds, AC-DABS1 and AC-DABS2, are effective durable press finishing agents under the alkaline condition, and can impart satisfactory fabric WRA and high TSR. The steaming process is better than the curing process and sodium carbonate is the proper alkaline for the crosslinking agents. The optimum durable press finishing process of AC-DABS1 and AC-DABS2 for cotton fabric is 80 g/L, sodium carbonate above 10 g/L and steaming at 110℃ with 75% humidity for 5 min. The WRA of cotton treated with AC-DABS1 and AC-DABS2 is not much better than that of FAP, which can be ascribed to the fact that there are three acrylamide groups in FAP, while there are only two acrylamide groups in the two newly synthesized compounds. More importantly, AC-DABS1 and AC-DABS2 are more soluble in water and more easily synthesized, which is of vital importance to durable press finishing in the textile industry.

Footnotes

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

Funding

The authors received no financial support for the research, authorship and/or publication of this article.

References

Schindler WD and Hauser P. Easy-care and durable press finishes of cellulosics. In: Chemical finishing of textiles. Cambridge: Woodhead, 2004, pp.51-72.

Ameri Dehabadi

Buschmann

H-J

Gutmann

. Durable press finishing of cotton fabrics: an overview. Text Res J 2013; 83: 1974–1995.

Harifi

Montazer

. Past, present and future prospects of cotton cross-linking: new insight into nano particles. Carbohydr Polym 2012; 88: 1125–1140.

Petersen

. The chemistry of crease-resist crosslinking agents. Rev Progr Coloration Relat Topic 1987; 17: 7–22.

Yang

. FTIR spectroscopy study of ester crosslinking of cotton cellulose catalyzed by sodium hypophosphite. Text Res J 2001; 71: 201–206.

Cogliano

Grosse

Baan

et al.

Advice on formaldehyde and glycol ethers. Lancet Oncol 2004; 5: 528–528.

Bosetti

McLaughlin

Tarone

et al.

Formaldehyde and cancer risk: a quantitative review of cohort studies through 2006. Ann Oncol 2008; 19: 29–43.

Peng

Yang

Wang

. Nonformaldehyde durable press finishing of cotton fabrics using the combination of maleic acid and sodium hypophosphite. Carbohydr Polym 2012; 87: 491–499.

Yang

. Effect of pH on nonformaldehyde durable press finishing of cotton fabric: FT-IR spectroscopy study: Part I: ester crosslinking. Text Res J 1993; 63: 420–430.

10.

Hebeish

Nassar

Ibrahim

et al.

Studies of some basic aspects in easy-care cotton finishing, IV. Effect of acid scavengers on free formaldehyde in and strength of crosslinked cotton. Angew Makromol Chem 1979; 82: 27–37.

11.

Lewis

Zhao

Tapley

. A new agent for cotton durable press finishing under alkaline conditions. AATCC Rev 2002; 2: 38–41.

12.

Welch

. tetracarboxylic acids as formaldehyde-free durable press reagents for cotton. Abstr Pap Am Chem S 1987; 194: 72–Cell.

13.

Hou

Sun

. Multifunctional finishing of cotton fabrics with 3,3',4,4'-benzophenone tetracarboxylic dianhydride: reaction mechanism. Carbohydr Polym 2013; 95: 768–772.

14.

Dehabadi

Buschmann

H-J

Gutmann

. Durable press finishing of cotton fabrics with polyamino carboxylic acids. Carbohydr Polym 2012; 89: 558–563.

15.

Huang

et al.

Anti-crease finishing of cotton fabrics based on crosslinking of cellulose with acryloyl malic acid. Carbohydr Polym 2016; 135: 86–93.

16.

Hashem

Refaie

Goli

et al.

Enhancement of wrinkle free properties of carboxymethylated cotton fabric via ionic crosslinking with poly(vinylpyrrolidone). J Ind Text 2009; 39: 57–80.

17.

Fahmy

. Utilization of poly(N-vinyl-2-pyrrolidone) in easy care finishing of cotton fabrics to improve their performance properties and antibacterial activities. J Ind Text 2009; 39: 109–122.

18.

Hashem

Elshakankery

El-Aziz

SMA

et al.

Improving easy care properties of cotton fabric via dual effect of ester and ionic crosslinking. Carbohydr Polym 2011; 86: 1692–1698.

19.

Fahmy

. Enhancing some performance properties of ester crosslinked cotton fabric by pre-quaternization. Egypt J Chem 2004; 47: 627–639.

20.

Welch

. Tetracarboxylic acids as formaldehyde-free durable press finishing agents: Part I: catalyst, additive, and durability studies 1. Text Res J 1988; 58: 480–486.

21.

Yang

Lan

Shiqi

et al.

Nonformaldehyde durable press finishing of cotton fabrics by combining citric acid with polymers of maleic acid. Text Res J 1998; 68: 457–464.

22.

Yang

Chen

Guan

et al.

Cross-linking cotton cellulose by the combination of maleic acid and sodium hypophosphite. 1. Fabric wrinkle resistance. Ind Eng Chem Res 2010; 49: 8325–8332.

23.

Ibrahim

Abo-Shosha

Elnagdy

et al.

Eco-friendly durable press finishing of cellulose-containing fabrics. J Appl Polym Sci 2002; 84: 2243–2253.

24.

Hashem

Ibrahim

El-Shafei

et al.

An eco-friendly – novel approach for attaining wrinkle – free/soft-hand cotton fabric. Carbohydr Polym 2009; 78: 690–703.

25.

Kang

Yang

Weishu

et al.

Mechanical strength of durable press finished cotton fabrics: Part I: effects of acid degradation and crosslinking of cellulose by polycarboxylic acids. Text Res J 1998; 68: 865–870.

26.

Yang

Wei

Lickfield

. Mechanical strength of durable press finished cotton fabric - Part III: change in cellulose molecular weight. Text Res J 2000; 70: 910–915.

27.

Frick

Andrews

BAK

Reid

. Effects of cross-linkage in wrinkle-resistant cotton fabrics. Text Res J 1960; 30: 495–504.

28.

. Cotton fabric strength loss from treatment with polycarboxylic acids for durable press performance. Text Res J 2000; 70: 957–961.

29.

Bates

Maudru

Phillips

DAS

et al.

Cross-linking agents for the protection of lyocell against fibrillation: synthesis, application and technical assessment of 2,4-diacrylamidobenzenesulphonic acid. Color Technol 2004; 120: 293–300.

Synthesis and application of an alkaline crosslinking agent containing acrylamide as the durable press finishing agent on cotton fabric

Abstract

Keywords

Experimental details

Materials and chemicals

Synthesis

Synthesis of AC-DABS1

Synthesis of AC-DABS2

Synthesis of AC-PABS

Durable press finishing of cotton fabric

Characterization and measurement

HPLC

1HNMR

Measurements of WRA, tearing strength retention and WI

Investigating the stability of the acrylamide group in the alkaline condition

Investigating the reactivity of the acrylamide group with cellulose

Results and discussion

Stability of the acrylamide group in the alkaline condition

Efficiency of durable press finishing by the steaming and curing process

Factors influencing the performance of cotton fabric treated with AC-DABS1

Comparison of the performance of cotton fabric treated by AC-DABS2 and AC-DABS1

Comparing the crosslinking efficiency of FAP and acrylamide-containing crosslinking agents for cotton fabric

Conclusion

Footnotes

Declaration of conflicting interests

Funding

References

¹HNMR