Chemically modified cellulose nanocrystals as polyanion for preparation of polyelectrolyte complex
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Bacterial cellulose nanocrystals (BCNCs) have hydrophilic surfaces due to hydroxyl groups but are water-insoluble. The carboxymethylation improves the solubility of cellulose in polar media through the insertion of carboxymethyl groups. This study aims to evaluate the use of two different alcoholic solvents in the carboxymethylation reaction of BCNCs: ethanol and isopropanol. BCNCs were obtained under two hydrolysis conditions: sulfuric acid (BCNC-S) and combination of sulfuric and hydrochloric acids (BCNC-S/Cl). Two techniques (NMR and titration) were used to determine the degree of substitution (DS) values. Carboxymethylation of BCNC-S/Cl led to high DS compared to BCNC-S and the use of isopropanol promoted an even greater DS. The thermal properties were not affected after the chemical modification. However, functionalization provided an increase in the negative charge density at the surface of nanostructures and a change in the crystal structure (cellulose type Iα for amorphous), making this material a potential polyanion for the synthesis of polyelectrolyte complexes (PECs). The micrographs showed that the nanocrystals became soluble after carboxymethylation. Carboxymethylated bacterial cellulose nanocrystals hydrolyzed through the mixture of inorganic acids and modified using isopropanol (CBCNC-S/Cl-IPA) was a suitable polyanion to produce PECs with chitosan. The PECs produced had particle size ranging from 276 to 588 nm and zeta potential ranging from − 24.3 to + 39.0 mV.
KeywordsBacterial cellulose Hydrolysis Nanocrystals Carboxymethylation Chitosan Polyelectrolytic complexes
The authors wish to acknowledge the financial support provided by the Coordination for the Improvement of Higher Education Personnel (CAPES, Brazil), the National Council of Technological and Scientific Development (CNPq, Brazil), the Foundation for Science and Technology (FCT, Portugal), the Institute for Biotechnology and Bioengineering (IBB, University of Minho, Portugal), Instituto Nacional de Ciência e Tecnologia em Materiais Complexos Funcionais (INOMAT, Brazil), and the Embrapa Agroindústria Tropical. This research was also supported by the international collaboration program FCT/CAPES (No. 99999.008530/2014-09). The authors would like to thank the Fundação Oswaldo Cruz (FIOCRUZ – Instituto Aggeu Magalhães) and the Laboratório de Raios-X (LRX – UFC) for supporting the analysis of TEM and XRD, respectively.
- Ambjörnsson HA, Schenzel K, Germgard U (2013) Carboxymethyl cellulose produced at different mercerization conditions and characterized by NIR FT Raman spectroscopy in combination with multivariate analytical methods. BioResources 8(2):1918–1932Google Scholar
- Bigucci F, Abruzzo A, Vitali B, Saladini B, Cerchiara T, Gallucci MC, Luppi B (2015) Vaginal inserts based on chitosan and carboxymethylcellulose complexes for local delivery of chlorhexidine: preparation, characterization and antimicrobial activity. Int J Pharm 478:456–463. https://doi.org/10.1016/j.ijpharm.2014.12.008 CrossRefPubMedGoogle Scholar
- Chawla PR, Bajaj IB, Survase SA, Singhal RS (2009) Microbial cellulose: fermentative production and applications. Food Technol Biotechnol 47:107–124Google Scholar
- Gama M, Gatenholm P, Klemm D (eds) (2012) Bacterial nanocellulose: a sophisticated multifunctional material (chapter 2). CRC Press, Boca RatonGoogle Scholar
- McMurry J (2013) Organic chemistry (chapter 2), 7th edn. Cengage Lernaning, São PauloGoogle Scholar
- Mukarakate C, Mittal A, Ciesielski PN, Budhi S, Thompson L, Iisa K, Nimlos MR, Donohoe BS (2016) Influence of crystal allomorph and crystallinity on the products and behavior of cellulose during fast pyrolysis. ACS Sustain Chem Eng 4(9):4662–4674. https://doi.org/10.1021/acssuschemeng.6b00812 CrossRefGoogle Scholar
- Pecoraro E, Manzani D, Messaddeq Y, Ribeiro SJ (2008) Monomers, polymers and composites from renewable resources. Bacterial cellulose from Glucanacetobacter xylinus: preparation, properties and applications, 1st edn. Elsevier, Oxford, pp 369–384Google Scholar
- Pereira ALS, Nascimento DMD, de Souza Filho M, Sá M, Morais JPS, Vasconcelos NF, Feitosa JPA, de Rosa MF (2014) Improvement of polyvinyl alcohol properties by adding nanocrystalline cellulose isolated from banana pseudostems. Carbohydr Polym 112:165–172. https://doi.org/10.1016/j.carbpol.2014.05.090 CrossRefPubMedGoogle Scholar
- Qi H, Liebert T, Meister F, Heinze T (2009) Homogenous carboxymethylation of cellulose in the NaOH/urea aqueous solution. React Funct Polym 69:779–784. https://doi.org/10.1016/j.reactfunctpolym.2009.06.007 CrossRefGoogle Scholar
- Scherrer P (1918) Bestimmung der Größe und der inneren Struktur von Kolloidteilchen mittels Röntgenstrahlen. Nachrichten von der Gesellschaft der Wissenschaften zu Göttingen, Mathematisch-Physikalische Klasse, pp 98–100. http://resolver.sub.uni-goettingen.de/purl?PPN252457811_1918. Accessed 5 Dec 2018.
- Vasconcelos NF, Feitosa JPA, Gama FMP, Morais JPS, Andrade FK, Souza MSM, Rosa MF (2017) Bacterial cellulose nanocrystals produced under different hydrolysis conditions: properties and morphological features. Carbohydr Polym 155:425–431. https://doi.org/10.1016/j.carbpol.2016.08.090 CrossRefPubMedGoogle Scholar