Cellulose Graft Copolymers Research Articles

Oral delivery of Sunitinib malate using carboxymethyl cellulose/poly(acrylic acid-itaconic acid)/Cloisite 30B nanocomposite hydrogel as a pH-responsive carrier.

This work aimed to fabricate a Cloisite 30B-incorporated carboxymethyl cellulose graft copolymer of acrylic acid and itaconic acid hydrogel (Hyd) via a free radical polymerization method for controlled release of Sunitinib malate anticancer drug. The synthesized samples were characterized by FTIR, XRD, TEM, and SEM-dot mapping analyses. The encapsulation efficiency of Hyd and Hyd/Cloisite 30B (6 wt%) was 81 and 93%, respectively, showing the effectiveness of Cloisite 30B in drug loading. An in vitro drug release study showed that drug release from all samples in a buffer solution with pH 7.4 was higher than in a buffer solution with pH 5.5. During 240min, the cumulative drug release from Hyd/Cloisite 30B (94.97% at pH 7.4) is lower than Hyd (53.71% at pH 7.4). Also, drug-loaded Hyd/Cloisite 30B (6 wt%) demonstrated better antibacterial activity towards S. Aureus bacteria and E. Coli. High anticancer activity of Hyd/Cloisite 30B against MCF-7 human breast cancer cells was shown by the MTT assay, with a MCF-7 cell viability of 23.82 ± 1.23% after 72-hour incubation. Our results suggest that Hyd/Cloisite 30B could be used as a pH-controlled carrier to deliver anticancer Sunitinib malate.

Graft Copolymers of Carboxymethyl Cellulose and Poly(N-vinylimidazole) as Promising Carriers for Metronidazole

Graft Copolymers of Carboxymethyl Cellulose and Poly(N-vinylimidazole) as Promising Carriers for Metronidazole

Photoinduced Metal-Free Atom Transfer Radical Polymerization for the Modification of Cellulose with Poly(N-isopropylacrylamide) to Create Thermo-Responsive Injectable Hydrogels.

Photoinduced metal-free ATRP has been successfully applied to fabricate thermo-responsive cellulose graft copolymer (PNIPAM-g-Cell) using 2-bromoisobuturyl bromide-modified cellulose as the macroinitiator. The polymerization of N-isopropylacrylamide (NIPAM) from cellulose was efficiently activated and deactivated with UV irradiation in the presence of an organic-based photo-redox catalyst. Both FTIR and 13C NMR analysis confirmed the structural similarity between the obtained PNIPAM-g-Cell and that synthesized via traditional ATRP methods. When the concentration of the PNIPAM-g-Cell is over 5% in water, it forms an injectable thermos-responsive hydrogel composed of micelles at 37 °C. Since organic photocatalysis is a metal-free ATRP, it overcomes the challenge of transition-metal catalysts remaining in polymer products, making this cellulose-based graft copolymer suitable for biomedical applications. In vitro release studies demonstrated that the hydrogel can continuously release DOX for up to 10 days, and its cytotoxicity indicates that it is highly biocompatible. Based on these findings, this cellulose-based injectable, thermo-responsive drug-loaded hydrogel is suitable for intelligent drug delivery systems.

Ammonium salts of microcrystalline cellulose-g-poly (acrylonitrile): toxicity, antioxidant and anti-inflammatory properties

Cellulose is an excellent starting material for the construction of bioactive polymers. In the present work, we have synthesized quaternized graft copolymers of cellulose and tested their biological properties. Cellulose was grafted with acrylonitrile in a cerium ion catalyzed reaction. High yield of the grafting reaction, 89%, was achieved. Next, the poly (acrylonitrile) chains were aminated using three different amines and finally, the amino functions were quaternized using methyl iodide. In addition to chemical and physical characterization of the polymers, several tests on their bioactive properties have been conducted. The polymers turned out to have good antioxidant properties, as assessed studying how they scavenge ABTS radicals. Anti-inflammatory properties were investigated by a membrane stabilization method. The results showed that the quaternized polymers had anti-inflammatory effects and the one aminated with tris(2-aminoethyl)amine was the most significant compared with indomethacin. The cytotoxicity was evaluated in vitro against HepG2 and WI-38 cell lines. All quaternized polymers showed moderate effects against the cancerous cell line HEPG2. On the other hand, their effect against normal fibroblast WI-38 was weak. The acute toxicity in vivo was evaluated for one of the polymers, for which the LD50 was 6606 mg/kg. The high LD50 indicates the polymer is relatively non-toxic, and will be considered in future for in vivo studies.Graphical abstract

Green synthesis of cellulose graft copolymers for anion exchange water purification

Green synthesis of cellulose graft copolymers for anion exchange water purification

The synthesis of multifunctional cellulose graft alternating copolymers of 3,4-dihydrocoumarin and epoxides in DBU/DMSO/CO2 solvent system

Cellulose graft copolymers having well-defined structures could incorporate the characteristics of both the cellulose skeleton and side chains, providing a new method for the preparation functionalised cellulose derivatives. Herein, a series of multifunctional cellulose grafted, alternating 3,4-dihydrocoumarin (DHC) and epoxide (EPO) copolymers (cell-g-P(DHC-alt-EPO)) were prepared in a metal-free DBU/DMSO/CO2 solvent system without adding additional catalyst. Four examples of cell-g-P(DHC-alt-EPO) with tunable thermal and optical properties were synthesized by copolymerization of DHC with styrene oxide (SO), propylene oxide (PO), cyclohexene oxide (CHO) or furfuryl glycidyl ether (FGE) onto cellulose. The nonconjugated cell-g-P(DHC-alt-EPO) showed UV absorption properties with the maximum absorption peak at 282 nm and 295 nm and photoluminescence performance. A clustering-triggered emission mechanism was confirmed and consistent with DFT theoretical calculations. In DMSO solution, the copolymer (DHCSO5) with DP of 11.64 showed ACQ behaviour as the concentration increased. In addition, DHCSO5 had good antioxidant capacity with an instantaneous radical scavenging activity of 2,2-diphenyl-1-picrylhydrazine (DPPH) up to 65 % at a concentration of 40 mg/ ml and increased to 100 % after 30 min. Thus, the multifunctional cell-g-P(DHC-alt-EPO) materials had a variety of potential applications in the fields of fluorescent printing, bio-imaging, UV- shielding and antioxidants.

The versatile world of cellulose-based materials in healthcare: From production to applications

Cellulose is the most abundant natural biopolymer that can be extracted directly from plants using various treatments (alkalis, acids, ultrasonic or enzymatic treatments) or produced by microbial fermentation. It is biodegradable, biocompatible, noncytotoxic, nongenotoxic, and easily amendable, making it the most desirable material for use in the biomedical and pharmaceutical industries. The thermal, surface, and mechanical properties can be improved by using surface modification or blending with other natural polymers like alginate, polylactic acid, gelatin, etc., or using metal-based nanoparticles. Such nanocomposites, cellulose graft co-polymers, and nanocrystals have been widely explored for applications in food, textile, wastewater, biomedical and pharmaceutical industries. Cellulose-derived materials have shown tremendous potential to be used as the backbone for developing wound dressings, face masks, fabrication of hydrogels, scaffolds for tissue engineering, biosensors, blood vessels, biomedicines, and drug delivery systems. The current review provides insights into cellulose production from different resources and its modification to produce high-value-added materials for biomedical applications.

Biomimetic ultra-strong, ultra-tough, degradable cellulose-based composites for multi-stimuli responsive shape memory

Fabrication of ultra-strong, ultra-tough, sustainable, and degradable bio-based composites is urgently needed but remains challenging. Here, a biomimetic sustainable, degradable, and multi-stimuli responsive cellulose/PCL/Fe3O4 composite with ultra-strong mechanical strength and ultra-high toughness was developed. To prepare the proposed composites, the soft poly(ε-caprolactone) (PCL) side chain was grafted onto the rigid cellulose backbone, then the cellulose graft copolymer (EC-g-PCL) reacted with rigid hexamethylenediamine modified Fe3O4 nanoparticle (Fe3O4-NH2) to construct the crosslinking network using MDI-50 as a crosslinker. Given by the construction of crosslinking network and the “hard” and “soft” interactive structure, the composites showed ultra-strong mechanical strength (25.7 MPa) and ultra-high toughness (107.0 MJ/m3), and the composite specimen could lift a weight of approximately 21,200 times its mass. The composites also exhibited rapid degradation ability with high degradation efficiency. In addition, the composites showed excellent thermal responsive shape memory property with a shape recovery ratio above 96 %. Most importantly, the Fe3O4 nanoparticles endowed the composites with photothermal conversion property, the composites exhibited superior NIR light-triggered shape memory capability. The EC-g-PCL/Fe3O4 composites with ultra-strong mechanical strength and ultra-high toughness have promising applications in heavy-lift, object transportation, and self-tightening knots.

Enhanced permeability of cellulose acetate ultrafiltration membrane by incorporation of cellulose graft copolymer

Enhanced permeability of cellulose acetate ultrafiltration membrane by incorporation of cellulose graft copolymer

Cellulose-based thermosensitive supramolecular hydrogel for phenol removal from polluted water

Pollution of phenolic effluent from spice and plastics factories has become increasingly serious. Thus, developing a green and highly efficient adsorbent to remove phenolic compounds from wastewater is of urgent need. In this study, cellulose graft copolymer was synthesized through grafting 4-vinylpyridine monomer and polyethylene glycol methacrylate to a molecular skeleton of cellulose by free radical polymerization. The supramolecular hydrogel was successfully synthesized by physical cross-linking of cellulose graft copolymer and α-cyclodextrin. These supramolecular hydrogels were thoroughly characterized and the adsorption performance (adsorption isotherms and adsorption kinetics) of phenol on the supramolecular hydrogel were investigated in batch operation. The supramolecular hydrogel not only exhibited excellent adsorption of phenol, but also demonstrated increased mechanical strength due to the introduction of a modified cellulose base material. The adsorption kinetics of phenol on the supramolecular hydrogel followed a quasi-second-order reaction, with a correlation coefficient of 0.9909. The adsorption isotherm conformed to the Langmuir adsorption isotherm, and the maximum adsorption capacity of phenol can reach 80.71 mg g−1, which was 2–3 times higher than traditional carbon-based materials. The results demonstrate the great promise of the waste-derived supramolecular hydrogel to be used as an efficient adsorbent in wastewater treatment.

Long term antibacterial effect cellulose film was modified with polyhexamethylene biguanide (PHMB)

Cellulose products such as textile, paper, package and so on are apt to breed bacterial. In this study, AA-PHMB antibacterial agent was synthesized innovatively. It was grafted onto cellulose by the addition polymerization of carbon carbon double bonds and hydroxyl groups to prepare cellulose antibacterial film with excellent performance. The structures, elements, mechanical properties and antibacterial activities of films were studied. The results showed that CN absorption at 1631 cm−1 of guanidine and the amide group absorption peak at 1554 cm−1 appeared on cellulose graft copolymers; employing SEM-EDS, a great quantity of deposited materials, with the elements of C, O and N, were observed on the grafted cellulose. The graft percentage of cellulose-AA-PHMB was about 62%. Compared with unmodified cellulose films, the mechanical properties of PHMB-AA-cellulose film were lower, and the crystallinity of the PHMB-AA-cellulose film was lower than that of original cellulose film. The modified film as a raw material had a good inhibitory effect on Escherichia coli and Staphylococcus aureus was proved by bacteriostatic experiments. Under the condition of continuous culture for 15 days, it still had a good bacteriostatic effect on the above strains, and therefore the cellulose-AA-PHMB films were long term antibacterial effect materials.

Response Surface Method Based Modeling and Optimization of CMC-g Terpolymer Interpenetrating Network/Bentonite Superabsorbent Composite for Enhancing Water Retention.

Water shortages have become a serious issue, so the importance of developing innovative cellulose-based superabsorbent polymer (SAP) was experimentally assessed as an environmentally friendly alternative to acrylate-based SAPs for the optimization of water consumption. The development of a biodegradable superabsorbent hydrogel composite based on a graft copolymer of carboxymethyl cellulose (CMC) and mixtures of different comonomers such as an acrylamide-co-acrylic acid-co-2-acrylamido-2-methylpropanesulfonic acid (Am-co-AA-co-AMPS) CMC-g-TerPoly interpenetrating network was characterized by infrared spectroscopy (FT-IR), scan electron microscopy (SEM), atomic force microscope (AFM), thermal gravimetric analysis (TGA), and swelling capacity in different aqueous media. The optimized CMC-g-(TerPoly) composite showing outstanding superabsorbance with high water retention, the ratio of constituents, temperature, and pH effect on equilibrium swelling have been optimized by using multistage response surface methodology (RSM). In distilled water (d-water), the equilibrium water absorption capacity (EW) of the synthesized composite hydrogels (SAP-IPN1) is 1200 g (d-water/1g hydrogel) which is superior to any other commercial polyacrylate SAP hydrogels, while in saline water the EW is 650 g (s-water/1g hydrogel). The performance of the SAP-IPN for water retention was evaluated by studying several swelling/deswelling cycle measurements. The prepared SAP-IPN hydrogels were found to show pH and salt solution dependence on the swelling behavior. The new SAP-IPN can work with commercial SAP, which is recommended for application as a water reservoir in arid land for irrigation for agriculture purposes.

Study on preparation of cationic flocculants by grafting binary monomer on cellulose substrate by γ-ray co-irradiation

Carboxymethyl cellulose (CMC) and wood flour cellulose (WFC) graft copolymers were prepared from acrylamide/dimethyl diallyl ammonium chloride (AM/DMDAAC) by γ-ray co-irradiation graft copolymerization method. CMC could obtain an excellent grafting effect at the absorbed dose of 6 kGy and CMC/AM/DMDAAC ratio of 0.2 g:2 g:1 ml, and the grafting rate, grafting efficiency, cationic degree and grafting efficiency of DMDAAC monomer were 790%, 46.01%, 20.17% and 64.56% respectively. Relatively, when the ratio of AM and DMDAAC was 3 g:1 ml and the absorbed dose was 8 kGy, the grafting effect of WFC was the optimum, and the more WFC added, the better graft copolymerization effect. The flocculation effect of the products and cationic polyacrylamide on kaolin wastewater was investigated, and the maximum turbidity removal rate of CMC graft copolymer on kaolin wastewater reached 86.0%, showing an excellent flocculation effect. The flocculation effect under different conditions was WFC graft copolymer＞CMC graft copolymer＞Cationic Polyacrylamide.

Poly(methacrylic Acid)-Cellulose Brushes as Anticancer Porphyrazine Carrier.

The prospective strategy for treatment of cancer is based on the application of nano-sized macromolecular carriers, which are able penetrate inside and can be accumulated within tumor tissue. In this work graft copolymers of cellulose and poly(methacrylic acid) has been prepared and tested as a nanocontainers for the delivery of drug to tumor. For this purpose, two derivatives of porphyrazine suitable for photodynamic cancer therapy were loaded into prepared polymer brush. Fluorescence imaging was applied for monitoring of accumulation of porphyrazine in the CT26 murine colon carcinoma. The selective accumulation of cellulose brush loaded with porphyrazine in tumor was demonstrated by fluorescence intensity contrast between the tumor area and normal tissues. The tumor growth rate after photodynamic therapy were assessed and inhibition of its growth was revealed.

Graft copolymer of sodium carboxymethyl cellulose and polyether polyol (CMC-g-TMN-450) improves the crosslinking degree of polyurethane for coated fertilizers with enhanced controlled release characteristics

Novel superhydrophobic sodium carboxymethyl cellulose (CMC) modified polyurethane (MPU) was developed as the membrane material for controlled-release fertilizer (CRF) by cross-linking polymerization of 4,4′-diphenylmethane diisocyanate (MDI) and CMC-based modified polyol (CMP) which was made by grafting CMC onto polyether polyol (TMN-450). The modified polyurethane coated fertilizer (MPUCF) was prepared by using MPU as the membrane material through a fluidized bed device. Analysis results of 13C NMR showed that the coatings of PUCF and MPUCF were prepared by connecting hydroxyl to isocyanate groups to form a carbamate. MPU had lower water absorption rates than PU, and MPUCF coating showed excellent hydrophobicity. Scanning electron microscope (SEM) revealed that MPUCF coating surface was much more smooth and flat than that of PUCF. Furthermore, the nitrogen (N) release longevity of MPUCF can increased to 140 days when the coating rate was 5%. It is concluded that MPU was an excellent superhydrophobic coating material for CRF.

Remarkable thermoplasticity of branched cellulose copolymers: Graft-chain-dependent structural transition and thermoplasticity

In this study, we designed novel methods to prepare a cellulose graft copolymer series (Cell-g-PDLs) with varied graft chain lengths, via direct ring-opening polymerization (ROP) of unmodified cellulose with alkyl-branched lactones. With increasing alkyl-branched graft chain length of the Cell-g-PDLs, the crystalline phase of cellulose became increasingly weakened, while the glass transition temperature significantly decreased. The latter was attributed to the extended free volume derived from the increased chain end-group concentrations of the branched graft chains. These results suggested that the incorporation of a highly alkyl-branched graft chain into unmodified cellulose is an effective way to improve its thermo-plasticity. Notably, the Cell-g-PDL with the longest graft chain (Cell-g-PDL9) was demonstrative of highly sufficient thermo-plasticity, owing to the enhanced molecular mobility resulting from the reduced frictional forces between the cellulose molecules.

A Study in Sorption of Cu+2 , Fe+2 and I2 onto Graft copolymers of Cellulose with N-Vinyl Pyrrolidone and Butyl Acrylate, and Their Functionalized Derivatives

Cellulose is of special interest due to its abundance in nature and it provides excellent materials for membranes both in native and derivatized forms. Graft copolymers of cellulose when used in separation and enrichment technologies have advantages over the conventional ones, due to chemical resistance, radiation stability and low cost of preparation. Cellulose based graft copolymers and hydrogels offer large hydrophilic area despite being insoluble in water and enrich or separate metal ion by binding, adsorption, chelation and ion exchange processes. Potential of cellulose as sorbent can be improved by radiation and chemical grafting, crosslinking and polymer analogous reactions on some graft copolymers. Grafting of suitable monomers with hydrophobic and hydrophilic/ionic moieties combine high degree of selectivity, permeability and longer stability, and enables complexation with low molecular weight species. Incorporation of functional groups like nitrile, hydrazino, hydroxamic acid and phosphate by derivatization and post polymer reactions enhances metal ion sorption capacity of Cellulosics. In present study an attempt has been made to study the sorption of Fe+2, Cu+2 and I2 on select graft copolymers of cellulose with N-Vinylpyrrolidone (1-Vinyl-2-prrolidone, N-VP) and Butyl Acrylate(BuAc) on to cellulose and some of their functionalized derivatives, on the basis of lowest to highest percent grafting (Pg). An attempt has also been made to investigate selectivity in metal ion sorption and effects of structural aspects of functionalized graft copolymers to find their end-uses as cost effective and eco-friendly polymeric materials for waste water management technologies.

Synthesis of graft copolymers of carboxymethyl cellulose and N,N-dimethylaminoethyl methacrylate and their study as Paclitaxel carriers

The double-sensitive graft copolymers of sodium salt of carboxymethyl cellulose (Na-CMC) and N,N-dimethylaminoethyl methacrylate (DMAEMA) with different content are successfully synthesized by radical polymerization applying a redox initiator. Aqueous solution of the synthesized copolymers has a lower critical solution temperature (LCST) in the range of 37–44 °C, and the sizes of copolymer particles being multichain spherical negative-charged aggregates are in a 118–133 nm range. Na-CMC-g-PDMAEMA copolymer particles are stable in a 0.15 N NaCl aqueous solution and in the physiological pH range, which allows to apply them as vectors for targeted drug delivery. Conjugation between Paclitaxel (Ptx) and Na-CMC-g-PDMAEMA copolymer is due to hydrophobic and electrostatic interaction between functional groups of each component; copolymers are characterized by relatively high values of loading and encapsulation efficiencies of Ptx. In vitro release kinetics was also researched in acidic and neutral media at 38 °C. The release process of Ptx from a copolymer conjugate is described by Korsmeyer–Peppas kinetic model and limited by molecular diffusion.

Integration of metal-free ATRP and Diels-Alder reaction toward sustainable and recyclable cellulose-based thermoset elastomers

Well-defined sustainable and recyclable thermoset elastomers derived from cellulose, fatty acid and furfural were successfully prepared via photoinduced metal-free ATRP and Diels-Alder (DA) reaction. Firstly, metal free ATRP was applied to prepare a range of thermoplastic cellulose graft copolymers with furfural groups. Then, a modified epoxidized soybean oil bearing 6-maleimidohexanoic group (ESOM) as a crosslinker was employed to perform DA reaction with furfural groups in these cellulose graft copolymers, by which the copolymer formed the dynamic crosslinked network and achieved the thermoset elastomers. The dynamic crosslinked network formed by DA reaction not only could increase the chain entanglement that was associated with the improved flexibility and could contribute to enhancing the mechanical strength up to 166 %, but also endowed these thermoset elastomers with recyclability, excellent shape memory and self-healing property. These thermoset elastomers can be used as self-healing strain sensor and wearable sensing devices after compounding them with carbon nanotubes.

Helical poly(phenyl isocyanide)s grafted selectively on C-6 of cellulose for improved chiral recognition ability

Cellulose graft copolymers are an effective way to endow new properties to cellulose substrate, as well the rigidity, regularity, and helicity of the cellulose backbone could induce the self-assembly of supramolecular structures. In this work, right-handed helical poly(phenyl isocyanide)s (PPIn) were grafted selectively onto C-6-cellulose. Alkyne-terminated PPIn was synthesized by living polymerization of right-handed phenyl isocyanide monomer using an alkyne-terminated palladium(II) complex as an initiator/catalyst, and were grafted onto the C-6 of the cellulose backbone (Cell-6-g-PPIn) at various chain lengths using copper-catalyzed alkyne-azide cycloaddition (CuAAC) “click” chemistry. We confirmed the successful grafting by liquid 1H NMR and 13C NMR, as well as solid 13C NMR, FTIR, and GPC. After grafting onto cellulose, the right-handed chirality of PPIn was significantly increased by 111.2%. Additionally, the Cell-6-g-PPIn exhibited better chiral recognition of L-Phe-DNSP than PPIn alone. Therefore, the helical cellulose backbone has enhanced effect on preferred helix of PPIn.