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Synthesis of cellulose acetate using as raw material textile wastes
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Synthesis of cellulose acetate using as raw material textile wastes Natália Cândido Homem a,b,⇑, Maria Teresa Pessoa Amorim a a b
2C2T – Centro de Ciência e Tecnologia Têxtil, Universidade do Minho, Guimarães 4800-019, Portugal Department of Chemical Engineering, State University of Maringá, Maringá, 87020-900, Brazil
a r t i c l e
i n f o
Article history: Received 4 June 2019 Received in revised form 23 January 2020 Accepted 27 January 2020 Available online xxxx Keywords: Biopolymer Cellulose derivatives Cotton Natural polymers Textile reuse
a b s t r a c t Several tons of textiles are wasted annually in world, mainly composed of fibers or cotton, which are currently disposed of in landfills or incinerated. These textile wastes are a valuable resource, for being rich in cellulose, which through chemical processes can become value-added products. Considering the importance of reducing the environmental impact that these industries cause, it is necessary to investigate solutions to reuse of these materials. In this scenario, the production of cellulose derivatives has been extremely important. The cellulose can be esterified to obtain cellulose acetate (CA), which is one of the most important commercial cellulose derivatives due to its wide industrial applications. Thus, this study aimed to evaluate the use of textile wastes provided by a textile industry of Portugal, in the synthesis of CA. The CA was produced through the homogeneous acetylation method and characterized by Fourier transform infrared spectroscopy (FTIR) and degree of substitution (DS). The CA produced presented an average DS of 2.69. The FTIR spectra showed the appearance of new bands which proved that acetylation occurred. These results showed that is possible to obtain CA, without any previous purification steps, by a simple method. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 4th International Conference on Natural Fibers – Smart Sustainable Materials.
1. Introduction Cellulose is a natural polymer which is considered the most abundant natural polymer on earth. It is a polysaccharide, coming from the junction of glucose molecules, which presents linear structure and high molecular weight [1,2]. The cellulose is of great importance worldwide, mainly because of its abundance in nature, its biodegradability and its lower environmental impact in comparison with polymers obtained from fossil sources [3]. Industrially, the cellulose of the wood (pines, eucalyptus, etc) is used in the production of paper and due to its fibrous structure, the natural cellulose fibers of cotton are used on the manufacturing of textiles. It is known that the textile industries are among the most pollutant in the world, generating vast amounts of residues. It is estimated that around 10 million tons of textiles are wasted annually in Europe and America, corresponding 7.5 million tons to preconsumer or industrial waste. These wastes, mainly composed of
⇑ Corresponding author at: 2C2T – Centro de Ciência e Tecnologia Têxtil, Universidade do Minho, Guimarães 4800-019, Portugal. E-mail address: [email protected] (N.C. Homem).
fibers or cotton, are currently disposed of in landfills or incinerated [4]. Each repeated unit of cellulose possesses three hydroxyl groups, and various derivative compounds can be synthesized by replacing these free OH groups for other chemical groups, such as methyl, acetyl, carboxymethyl, etc. When the cellulose molecule is esterified with acetic anhydride, cellulose acetates are obtained [2,5]. The CA is considered one of the most important cellulose derivatives due to its several industrial applications, such as plastic films, textile fibers, filtration membranes, paints, cigarette filters, coats, dialyzers, drugs and biomedical utilities [3,6–8]. Considering the importance of generating a circular economy, it is possible to verify the existence of a knowledge gap regarding the reuse of these materials, in order to reduce the environmental impact that these industries cause. The textile wastes are a valuable resource, for being rich in cellulose, which through chemical processes can become value-added products. Some studies reported the efforts to synthesize CA from natural sources. Candido et al. (2016, 2017) presented a method for the synthesis and characterization of CA from sugarcane bagasse and sugarcane straw [2,9]. Cheng et al. (2010) studied the use of cottonseed hull and cotton burr in the synthesis of CA by an alternative process [7],
https://doi.org/10.1016/j.matpr.2020.01.494 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 4th International Conference on Natural Fibers – Smart Sustainable Materials.
Please cite this article as: N. C. Homem and M. T. P. Amorim, Synthesis of cellulose acetate using as raw material textile wastes, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.494
2
N.C. Homem, M.T.P. Amorim / Materials Today: Proceedings xxx (xxxx) xxx
and Das et al. (2014) used rice husk as raw material in the synthesis of CA [3]. However, in our best knowledge, none attempt was made to investigate the use of textile wastes in this aim. Thus, the goal of this study was to evaluate the application of textile wastes (100% cotton samples) provided by a textile industry of Portugal, in the synthesis of CA through the homogeneous acetylation method.
molarity (M), Va is the volume of HCl added to the system, la is the hydrochloric acid molarity (M), M is the molar weight of acetyl group (g mol1) and mCA is the weight of the CA sample (g). From the degree of acetylation it is possible to determine the degree of substitution of the sample [10].
2. Experimental section
3.1. FTIr
2.1. Materials
FTIR analysis of CA synthesized and a sample of CA commercial were performed, for comparison. The obtained spectra are presented at Fig. 1. As can be observed in Fig. 1, the spectrum for the CA synthesized in this study is very similar to the spectrum of the commercial CA. It can be observed the presence of a sharp band at 1748 cm1, which can be attributed to the stretching of ester carbonyl and is a characteristic of the acetyl groups. According to the literature, the appearance of this peak is one of the main indications that the cellulose was acetylated [3]. It is also possible to observe a band between 1300 and 1200 (1238 cm1), which is attributed to the C-O stretch of acetate. Furthermore, the band in 1376 cm1, which corresponds to the vibration of C–H bond, is also a band characteristic of the acetyl groups. Thus, the FTIR spectra suggests that the acetylation of the cellulose molecule was successfully performed [11].
Glacial acetic acid (CH3COOH, Pronalab), acetic anhydride ((CH3CO)2O, Sigma-Aldrich) and sulfuric acid (H2SO4, 98%, Sigma-Aldrich) were used in the synthesis of CA. Sodium hydroxide (NaOH, JMGS), sodium hydroxide solution (NaOH, 0.25 M, Merck), ethanol (CH3CH2OH, Merck) and hydrochloric acid (HCl, Merck) were used in the determination of the degree of substitution of CA. All chemicals were of analytical grade and used without any further purification. The textile wastes used as raw materials were composed by non-dyed 100% cotton samples. 2.2. CA synthesis The synthesis of the CA was carried out according to the conventional method, i.e. homogeneous acetylation of cellulose. In detail, the process is started by the addition of 40 mL of glacial acetic acid to 2.0 g of the cotton fabric previously cut into thin strips. This mixture was stirred for 30 min. Subsequently, a solution containing sulfuric acid and glacial acetic acid (0.3 mL and 17.5 mL, respectively) was added, and the mixture was stirred for another 15 min at room temperature. To this mixture, 20 mL of acetic anhydride was added, and the solution was stirred for another 30 min. Then, the solution was left to stand for 24 h, and after that 100 mL of distilled water was slowly added to the reaction medium, and the magnetic stirring was continued for 1 h. Finally, the CA was vacuum filtered, and washed with distilled water until pH 7 was reached. The material was oven dried overnight at 50 °C and stored in a desiccator for further characterization. All steps of the synthesis were performed at room temperature.
3. Results and discussion
3.2. Degree of substitution According Puleo et al. (1989), from the degree of acetylation (% GA) it is possible to determine the degree of substitution of the sample, since it is known that a degree of substitution 2.88 corresponds to a degree of acetylation of 43.5% [10]. Thus, the DS of the samples was calculated, and the results are presented at Table 1.
2.3. Characterization of CA The surface chemistry and chemical composition of the CA synthesized were analyzed by Fourier transform infrared spectroscopy (FTIR). The spectra were obtained in a Thermo Nicolet Avatar 360 FTIR equipment, at a wavenumber range of 400–4000 cm1, in a velocity scan of 32 scans min1 and resolution of 4 cm1. 2.4. Determination of the degree of substitution of CA The degree of acetylation was determined by acid-base titration. Initially, 5.0 mL of sodium hydroxide (0.25 mol L1) and 5.0 mL of ethanol were added to 0.10 g of CA and the mixture was allowed to stand for 24 h. After this period, 10 mL of hydrochloric acid (0.25 mol L1) was added and the mixture was allowed to stand for 30 min. The solution was then titrated with a standard NaOH solution using phenolphthalein as indicator. This test was performed in triplicate. The percentage of acetyl groups (% AG) was obtained by the following equation:
%GA ¼
Fig. 1. FTIR spectra of the initial sample and the CA synthesized.
Table 1 Degree of acetylation and degree of substitution for CA synthesized.
ðVbi þ Vbt Þ:lb Va :la :M:100 mCA
where Vbi is the volume of NaOH added to the system (L), Vbt is the volume of NaOH spent in titration (L), lb is the sodium hydroxide
*
Sample
%GA
DS
CA CArep1 CArep2 Average
40.69 41.26 40.12 40.69 ± 0.22*
2.69 2.73 2.65 2.69 ± 0.03*
Standard deviation.
Please cite this article as: N. C. Homem and M. T. P. Amorim, Synthesis of cellulose acetate using as raw material textile wastes, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.494
N.C. Homem, M.T.P. Amorim / Materials Today: Proceedings xxx (xxxx) xxx
As can be observed, the CA synthesized presented an average degree of substitution of 2.69, with a percentage of acetyl groups of 40.69%. These results indicate that, through the acetylation reaction, the hydroxyl groups were partially replaced by acetyl groups, and thus it was possible to obtain CA. 4. Conclusions This study showed that it is possible to obtain CA using preconsumption textile wastes which normally would be discarded, without any previous purification steps. Further tests should be performed in order to investigate applications for the CA synthesized, such as its use on the preparation of filtration membranes for the treatment of textile wastewater. It is important to emphasize the importance of results such as those obtained in the present study, once that it is becoming increasingly necessary to investigate technologies which can both add value to a material that is discarded every day in large quantities, as also contribute to the reduction of the environmental impact caused by the textile industries. CRediT authorship contribution statement Natália Cândido Homem: Conceptualization, Methodology, Validation, Investigation, Writing - original draft, Writing - review & editing, Visualization. Maria Teresa Pessoa Amorim: Conceptualization, Resources, Supervision, Funding acquisition, Project administration. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
3
Acknowledgements The authors gratefully acknowledge the Project UID/ CTM/00264/2019 of 2C2T – Centro de Ciência e Tecnologia Têxtil, funded by National Founds through FCT/MCTES and the Project TSSiPRO – Technologies for Sustainable and Smart Innovative Products (NORTE-01-0145-FEDER-000015), supported by FEDER funding on the Programa Operacional Regional do Norte (NORTE2020). References [1] M.S. Buckeridge, G.H. Goldman, Routes to cellulosic ethanol, Routes Cellular Ethanol. (2011) 1–266. [2] R.G. Candido, G.G. Godoy, A. Gonçalves, Characterization and application of cellulose acetate synthesized from sugarcane bagasse, Carbohydr. Polym. 167 (2017) 280–289. [3] A.M. Das, A.A. Ali, M.P. Hazarika, Synthesis and characterization of cellulose acetate from rice husk: eco-friendly condition, Carbohydr. Polym. 112 (2014) 342–349. [4] H.M. Silva, F.M. Bártolo, et al., Challenges for Technology Innovation: An Agenda for the Future, CRC Press, 2017. [5] L. Bottenbruch, Engineering thermoplastics: Polycarbonates, polyacetals, polyesters and cellulose esters, Chem. Eng. World 25 (1996) 497. [6] D.-G. Yu, J.-H. Yu, L. Chen, G.R. Williams, X. Wang, Modified coaxial electrospinning for the preparation of high-quality ketoprofen-loaded cellulose acetate nanofibers, Carbohydr. Polym. 90 (2012) 1016–1023. [7] H.N. Cheng, M.K. Dowd, G.W. Selling, A. Biswas, Synthesis of cellulose acetate from cotton byproducts, Carbohydr. Polym. 80 (2010) 450–453. [8] D.-G. Yu, X.-Y. Li, X. Wang, W. Chian, Y.-Z. Liao, Y. Li, Zero-order drug release cellulose acetate nanofibers prepared using coaxial electrospinning, Cellulose 20 (2013) 379–389, https://doi.org/10.1007/s10570-012-9824-z. [9] R.G. Candido, A.R. Gonçalves, Synthesis of cellulose acetate and carboxymethylcellulose from sugarcane straw, Carbohydr. Polym. 152 (2016) 679–686. [10] A.C. Puleo, D.R. Paul, S.S. Kelley, The effect of degree of acetylation on gas sorption and transport behavior in cellulose acetate, J. Memb. Sci. 47 (1989) 301–332. [11] J. Chen, J. Xu, K. Wang, X. Cao, R. Sun, Cellulose acetate fibers prepared from different raw materials with rapid synthesis method, Carbohydr. Polym. 137 (2016) 685–692.
Please cite this article as: N. C. Homem and M. T. P. Amorim, Synthesis of cellulose acetate using as raw material textile wastes, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.494
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Synthesis of cellulose acetate using as raw material textile wastes Natália Cândido Homem a,b,⇑, Maria Teresa Pessoa Amorim a a b
2C2T – Centro de Ciência e Tecnologia Têxtil, Universidade do Minho, Guimarães 4800-019, Portugal Department of Chemical Engineering, State University of Maringá, Maringá, 87020-900, Brazil
a r t i c l e
i n f o
Article history: Received 4 June 2019 Received in revised form 23 January 2020 Accepted 27 January 2020 Available online xxxx Keywords: Biopolymer Cellulose derivatives Cotton Natural polymers Textile reuse
a b s t r a c t Several tons of textiles are wasted annually in world, mainly composed of fibers or cotton, which are currently disposed of in landfills or incinerated. These textile wastes are a valuable resource, for being rich in cellulose, which through chemical processes can become value-added products. Considering the importance of reducing the environmental impact that these industries cause, it is necessary to investigate solutions to reuse of these materials. In this scenario, the production of cellulose derivatives has been extremely important. The cellulose can be esterified to obtain cellulose acetate (CA), which is one of the most important commercial cellulose derivatives due to its wide industrial applications. Thus, this study aimed to evaluate the use of textile wastes provided by a textile industry of Portugal, in the synthesis of CA. The CA was produced through the homogeneous acetylation method and characterized by Fourier transform infrared spectroscopy (FTIR) and degree of substitution (DS). The CA produced presented an average DS of 2.69. The FTIR spectra showed the appearance of new bands which proved that acetylation occurred. These results showed that is possible to obtain CA, without any previous purification steps, by a simple method. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 4th International Conference on Natural Fibers – Smart Sustainable Materials.
1. Introduction Cellulose is a natural polymer which is considered the most abundant natural polymer on earth. It is a polysaccharide, coming from the junction of glucose molecules, which presents linear structure and high molecular weight [1,2]. The cellulose is of great importance worldwide, mainly because of its abundance in nature, its biodegradability and its lower environmental impact in comparison with polymers obtained from fossil sources [3]. Industrially, the cellulose of the wood (pines, eucalyptus, etc) is used in the production of paper and due to its fibrous structure, the natural cellulose fibers of cotton are used on the manufacturing of textiles. It is known that the textile industries are among the most pollutant in the world, generating vast amounts of residues. It is estimated that around 10 million tons of textiles are wasted annually in Europe and America, corresponding 7.5 million tons to preconsumer or industrial waste. These wastes, mainly composed of
⇑ Corresponding author at: 2C2T – Centro de Ciência e Tecnologia Têxtil, Universidade do Minho, Guimarães 4800-019, Portugal. E-mail address: [email protected] (N.C. Homem).
fibers or cotton, are currently disposed of in landfills or incinerated [4]. Each repeated unit of cellulose possesses three hydroxyl groups, and various derivative compounds can be synthesized by replacing these free OH groups for other chemical groups, such as methyl, acetyl, carboxymethyl, etc. When the cellulose molecule is esterified with acetic anhydride, cellulose acetates are obtained [2,5]. The CA is considered one of the most important cellulose derivatives due to its several industrial applications, such as plastic films, textile fibers, filtration membranes, paints, cigarette filters, coats, dialyzers, drugs and biomedical utilities [3,6–8]. Considering the importance of generating a circular economy, it is possible to verify the existence of a knowledge gap regarding the reuse of these materials, in order to reduce the environmental impact that these industries cause. The textile wastes are a valuable resource, for being rich in cellulose, which through chemical processes can become value-added products. Some studies reported the efforts to synthesize CA from natural sources. Candido et al. (2016, 2017) presented a method for the synthesis and characterization of CA from sugarcane bagasse and sugarcane straw [2,9]. Cheng et al. (2010) studied the use of cottonseed hull and cotton burr in the synthesis of CA by an alternative process [7],
https://doi.org/10.1016/j.matpr.2020.01.494 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 4th International Conference on Natural Fibers – Smart Sustainable Materials.
Please cite this article as: N. C. Homem and M. T. P. Amorim, Synthesis of cellulose acetate using as raw material textile wastes, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.494
2
N.C. Homem, M.T.P. Amorim / Materials Today: Proceedings xxx (xxxx) xxx
and Das et al. (2014) used rice husk as raw material in the synthesis of CA [3]. However, in our best knowledge, none attempt was made to investigate the use of textile wastes in this aim. Thus, the goal of this study was to evaluate the application of textile wastes (100% cotton samples) provided by a textile industry of Portugal, in the synthesis of CA through the homogeneous acetylation method.
molarity (M), Va is the volume of HCl added to the system, la is the hydrochloric acid molarity (M), M is the molar weight of acetyl group (g mol1) and mCA is the weight of the CA sample (g). From the degree of acetylation it is possible to determine the degree of substitution of the sample [10].
2. Experimental section
3.1. FTIr
2.1. Materials
FTIR analysis of CA synthesized and a sample of CA commercial were performed, for comparison. The obtained spectra are presented at Fig. 1. As can be observed in Fig. 1, the spectrum for the CA synthesized in this study is very similar to the spectrum of the commercial CA. It can be observed the presence of a sharp band at 1748 cm1, which can be attributed to the stretching of ester carbonyl and is a characteristic of the acetyl groups. According to the literature, the appearance of this peak is one of the main indications that the cellulose was acetylated [3]. It is also possible to observe a band between 1300 and 1200 (1238 cm1), which is attributed to the C-O stretch of acetate. Furthermore, the band in 1376 cm1, which corresponds to the vibration of C–H bond, is also a band characteristic of the acetyl groups. Thus, the FTIR spectra suggests that the acetylation of the cellulose molecule was successfully performed [11].
Glacial acetic acid (CH3COOH, Pronalab), acetic anhydride ((CH3CO)2O, Sigma-Aldrich) and sulfuric acid (H2SO4, 98%, Sigma-Aldrich) were used in the synthesis of CA. Sodium hydroxide (NaOH, JMGS), sodium hydroxide solution (NaOH, 0.25 M, Merck), ethanol (CH3CH2OH, Merck) and hydrochloric acid (HCl, Merck) were used in the determination of the degree of substitution of CA. All chemicals were of analytical grade and used without any further purification. The textile wastes used as raw materials were composed by non-dyed 100% cotton samples. 2.2. CA synthesis The synthesis of the CA was carried out according to the conventional method, i.e. homogeneous acetylation of cellulose. In detail, the process is started by the addition of 40 mL of glacial acetic acid to 2.0 g of the cotton fabric previously cut into thin strips. This mixture was stirred for 30 min. Subsequently, a solution containing sulfuric acid and glacial acetic acid (0.3 mL and 17.5 mL, respectively) was added, and the mixture was stirred for another 15 min at room temperature. To this mixture, 20 mL of acetic anhydride was added, and the solution was stirred for another 30 min. Then, the solution was left to stand for 24 h, and after that 100 mL of distilled water was slowly added to the reaction medium, and the magnetic stirring was continued for 1 h. Finally, the CA was vacuum filtered, and washed with distilled water until pH 7 was reached. The material was oven dried overnight at 50 °C and stored in a desiccator for further characterization. All steps of the synthesis were performed at room temperature.
3. Results and discussion
3.2. Degree of substitution According Puleo et al. (1989), from the degree of acetylation (% GA) it is possible to determine the degree of substitution of the sample, since it is known that a degree of substitution 2.88 corresponds to a degree of acetylation of 43.5% [10]. Thus, the DS of the samples was calculated, and the results are presented at Table 1.
2.3. Characterization of CA The surface chemistry and chemical composition of the CA synthesized were analyzed by Fourier transform infrared spectroscopy (FTIR). The spectra were obtained in a Thermo Nicolet Avatar 360 FTIR equipment, at a wavenumber range of 400–4000 cm1, in a velocity scan of 32 scans min1 and resolution of 4 cm1. 2.4. Determination of the degree of substitution of CA The degree of acetylation was determined by acid-base titration. Initially, 5.0 mL of sodium hydroxide (0.25 mol L1) and 5.0 mL of ethanol were added to 0.10 g of CA and the mixture was allowed to stand for 24 h. After this period, 10 mL of hydrochloric acid (0.25 mol L1) was added and the mixture was allowed to stand for 30 min. The solution was then titrated with a standard NaOH solution using phenolphthalein as indicator. This test was performed in triplicate. The percentage of acetyl groups (% AG) was obtained by the following equation:
%GA ¼
Fig. 1. FTIR spectra of the initial sample and the CA synthesized.
Table 1 Degree of acetylation and degree of substitution for CA synthesized.
ðVbi þ Vbt Þ:lb Va :la :M:100 mCA
where Vbi is the volume of NaOH added to the system (L), Vbt is the volume of NaOH spent in titration (L), lb is the sodium hydroxide
*
Sample
%GA
DS
CA CArep1 CArep2 Average
40.69 41.26 40.12 40.69 ± 0.22*
2.69 2.73 2.65 2.69 ± 0.03*
Standard deviation.
Please cite this article as: N. C. Homem and M. T. P. Amorim, Synthesis of cellulose acetate using as raw material textile wastes, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.494
N.C. Homem, M.T.P. Amorim / Materials Today: Proceedings xxx (xxxx) xxx
As can be observed, the CA synthesized presented an average degree of substitution of 2.69, with a percentage of acetyl groups of 40.69%. These results indicate that, through the acetylation reaction, the hydroxyl groups were partially replaced by acetyl groups, and thus it was possible to obtain CA. 4. Conclusions This study showed that it is possible to obtain CA using preconsumption textile wastes which normally would be discarded, without any previous purification steps. Further tests should be performed in order to investigate applications for the CA synthesized, such as its use on the preparation of filtration membranes for the treatment of textile wastewater. It is important to emphasize the importance of results such as those obtained in the present study, once that it is becoming increasingly necessary to investigate technologies which can both add value to a material that is discarded every day in large quantities, as also contribute to the reduction of the environmental impact caused by the textile industries. CRediT authorship contribution statement Natália Cândido Homem: Conceptualization, Methodology, Validation, Investigation, Writing - original draft, Writing - review & editing, Visualization. Maria Teresa Pessoa Amorim: Conceptualization, Resources, Supervision, Funding acquisition, Project administration. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
3
Acknowledgements The authors gratefully acknowledge the Project UID/ CTM/00264/2019 of 2C2T – Centro de Ciência e Tecnologia Têxtil, funded by National Founds through FCT/MCTES and the Project TSSiPRO – Technologies for Sustainable and Smart Innovative Products (NORTE-01-0145-FEDER-000015), supported by FEDER funding on the Programa Operacional Regional do Norte (NORTE2020). References [1] M.S. Buckeridge, G.H. Goldman, Routes to cellulosic ethanol, Routes Cellular Ethanol. (2011) 1–266. [2] R.G. Candido, G.G. Godoy, A. Gonçalves, Characterization and application of cellulose acetate synthesized from sugarcane bagasse, Carbohydr. Polym. 167 (2017) 280–289. [3] A.M. Das, A.A. Ali, M.P. Hazarika, Synthesis and characterization of cellulose acetate from rice husk: eco-friendly condition, Carbohydr. Polym. 112 (2014) 342–349. [4] H.M. Silva, F.M. Bártolo, et al., Challenges for Technology Innovation: An Agenda for the Future, CRC Press, 2017. [5] L. Bottenbruch, Engineering thermoplastics: Polycarbonates, polyacetals, polyesters and cellulose esters, Chem. Eng. World 25 (1996) 497. [6] D.-G. Yu, J.-H. Yu, L. Chen, G.R. Williams, X. Wang, Modified coaxial electrospinning for the preparation of high-quality ketoprofen-loaded cellulose acetate nanofibers, Carbohydr. Polym. 90 (2012) 1016–1023. [7] H.N. Cheng, M.K. Dowd, G.W. Selling, A. Biswas, Synthesis of cellulose acetate from cotton byproducts, Carbohydr. Polym. 80 (2010) 450–453. [8] D.-G. Yu, X.-Y. Li, X. Wang, W. Chian, Y.-Z. Liao, Y. Li, Zero-order drug release cellulose acetate nanofibers prepared using coaxial electrospinning, Cellulose 20 (2013) 379–389, https://doi.org/10.1007/s10570-012-9824-z. [9] R.G. Candido, A.R. Gonçalves, Synthesis of cellulose acetate and carboxymethylcellulose from sugarcane straw, Carbohydr. Polym. 152 (2016) 679–686. [10] A.C. Puleo, D.R. Paul, S.S. Kelley, The effect of degree of acetylation on gas sorption and transport behavior in cellulose acetate, J. Memb. Sci. 47 (1989) 301–332. [11] J. Chen, J. Xu, K. Wang, X. Cao, R. Sun, Cellulose acetate fibers prepared from different raw materials with rapid synthesis method, Carbohydr. Polym. 137 (2016) 685–692.
Please cite this article as: N. C. Homem and M. T. P. Amorim, Synthesis of cellulose acetate using as raw material textile wastes, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.01.494