Improvement of pesticide adsorption capacity of cellulose fibre by high-energy irradiation-initiated grafting of glycidyl methacrylate

Cellulose as a renewable raw material was used for preparation of adsorbent of organic impurities in wastewater treatment. Hydrophobic surface of cellulose substrate was developed by grafting glycidyl methacrylate in simultaneous grafting using gamma irradiation initiation. Water uptake of cellulose significantly decreased while adsorption of phenol and a pesticide molecule (2,4-dichlorophenoxyacetic acid: 2,4-D) increased upon grafting. Adsorption equilibrium data fitted the Freundlich isotherm for both solutes.     

The accessibility of cellulose as determined by dye adsorption

The accessibility of cotton cellulose was determined after it had been mercerized both in the slack and tension states. Mercerized samples were either dried or retained in the undried state before dyeing to determine their accessibilities by the adsorption of Direct Blue 1. Samples were characterized also by techniques such as moisture adsorption, water retention value (WRV) and X-ray analysis. It appeared that the crystallinity of cotton mercerized under tension was slightly increased during dyeing. Dye adsorption increased in the order nonmercerized <tension-mercerized <slack-mercerized. Products mercerized and not dried adsorbed more dye than counterparts given the same swelling treatment but dried after mercerization. The presence of dye in a sample mercerized and undried before dyeing did not affect its crystallinity. From both the dye adsorption and WRV data it was concluded that structural collapse of the fibre is greater for the slack-mercerized product than its tension-mercerized counterpart after it is dried. It was also concluded from dye adsorption and water adsorption data that about 34% of the internal surface of cotton and mercerized cotton, available for water adsorption, is inaccessible to Direct Blue 1.     

Development of reactive methacrylates based on glycidyl methacrylate

Six methacrylate monomers have been synthesized for use as reactive diluents in dental composites and evaluated to investigate the relationship between molecular structure and monomer reactivity. Four were synthesized by reactions of glycidyl methacrylate (GMA) with various acids, 2‐(2‐methoxyethoxy)acetic acid ( 1 ), 2‐(2‐(2‐methoxyethoxy)ethoxy)acetic acid ( 2 ), cyanoacetic acid ( 3 ), and benzoic acid ( 4 ); others were synthesized by reactions of GMA with diethyl hydrogen phosphate ( 5 ) or methanol ( 6 ). Monomers 1 and 2 are novel, 3 seems to be novel, 4 and 6 were synthesized via a novel method, and the synthesis of 5 was described in the literature. The monomers showed high crosslinking tendencies during thermal bulk polymerizations. The photo‐, homo‐, and copolymerization behavior of the monomers with 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy)phenyl]propane (Bis‐GMA) were investigated. The maximum rate of polymerizations of monomers 2 – 6 was found to be greater than triethyleneglycol dimethacrylate, Bis‐GMA, 2‐hydroxyethyl methacrylate, and glycerol dimethacrylate. For the more reactive monomers ( 2 , 3 , and 4 ), the oxygen sensitivity of polymerization was found to be low due to a hydrogen abstraction/chain transfer reaction. The computationally calculated dipole moment and lowest unoccupied molecular orbital energies indicated that there seems to be a correlation between these quantities and reactivity for ester linked monomers ( 1 – 5 ), which was also supported by ¹³C NMR data. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3787–3796, 2010     

Surface characterization of macroporous glycidyl methacrylate based copolymers by inverse gas chromatography

Two samples of macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), PGME, with different porosity parameters were synthesized by suspension copolymerization and modified by ring-opening reaction of the pendant epoxy groups with ethylene diamine, EDA. Inverse gas chromatography at infinite dilution was used for the determination of adsorption properties of PGME, and copolymer modified with ethylene diamine, PGME-en. Thermodynamic parameters of adsorption, dispersive components of the surface free energies, and the acid/base constants for the copolymer samples were calculated. The calculated dispersive surface energy values, , for PGME and PGME-en are comparable with the literature data for nonconductive polymers.     

Ion exchangers based on homo-and copolymers of vinyloxyethylamine and glycidyl methacrylate

An efficient method is developed for synthesis of highly permeable ion-exchange resins through the reaction of glycidyl methacrylate with polyvinyloxyethylamine and its copolymers with nitrogen-containing monomers with preservation of the nitrogen functional groups in the latter monomers. The synthesis conditions are optimized, and physicochemical and sorption properties of the resulting polymers are examined.     

Syntheses and characterizations of allyl cellulose and glycidyl cellulose

Allyl cellulose was synthesized by reacting cellulose with allyl bromide in homogeneous LiCl/DMAc solution containing NaOH powder. The degree of substitution (DS) per anhydroglucose (AHG) unit was determined by titrating the allyl cellulose with bromine in chloroform solution, and an allyl DS of 2.80 was found. Glycidyl cellulose was then prepared by reacting this allyl cellulose with peracetic acid in methylene chloride at ambient temperature for 6 days. The measured reaction rate constant was 1.33 × 10^?3 min^?1. The glycidyl cellulose thus obtained with a glycidyl DS of 2.58 was determined by titrating the product with perchloric acid in conjunction with tetrabutylammonium iodide. The 2.58 of glycidyl DS was also confirmed by ¹H-NMR integration. Both allyl cellulose and glycidyl cellulose were analyzed and characterized with FTIR, ¹H-NMR, ¹³C-NMR, TGA, and GPC. During epoxidation of allyl cellulose, possible side reaction leading to ester formation was evidenced from the continuous increase of v_{C? O} at 1735 cm^?1 in FTIR analyses. In addition, a bimodal distribution and a decreased molecular weight for glycidyl cellulose were found from GPC data, which might suggest a possible chain scission at the cellulosic ether linkage. © 1992 John Wiley & Sons, Inc.     

Preparation and performance analysis of monodisperse glycidyl methacrylate modified restricted access media-imprinted materials

Using monodisperse poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as the matrix, and pefloxacin template molecules, a novel restricted-access medium molecularly imprinted polymers with Bovine serum albumin crosslinked on its surface was prepared through reversible addition–fragmentation chain-transfer polymerization. Then, the obtained material was employed in dispersive solid-phase extraction to analyze the fluoroquinolones in untreated egg samples by high-performance liquid chromatography–ultraviolet detection. Adsorption performance revealed a good binding amount (40.72 mg/g), fast binding kinetics (25 min), satisfactory selectivity, and good ability to eliminate matrix interference. The reusability experiments indicated the materials have good reusable performance after repetition. Under the optimized conditions, restricted access media-molecularly imprinted polymers-dispersive solid-phase extraction was combined with high-performance liquid chromatography–ultraviolet to enrich fluoroquinolones in untreated eggs, good limit of detection (1.31–3.15 μg/L) and high recovery (89.5–96.8%) were obtained. The results showed that the prepared restricted-access material is promising for the direct detection of antibiotics in complex samples.     

Preparation of methyl methacrylate and glycidyl methacrylate copolymerized nonporous particles

Particles of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) copolymer having narrow size distributions were prepared by the method of dispersion polymerization. Results from the analysis of particle porosity and the correlation of specific surface area with the reciprocal of particle diameter suggest that the prepared particles were nonporous. The particle size was found to decrease from 4.2 to 2.1 μm with increasing the mass ratio of GMA/MMA from 0.1 to 0.75. Polymer particles having an average diameter falling in this range are suitable for being employed as the stationary phase in protein chromatography. The decrease in particle size when GMA was present could be due to the increase in adsorption rate of poly(vinyl pyrrolidone). The oligomer chains that were rich in GMA were more active for adsorbing and grafting PVP, compared with the moiety of MMA. An increase in the GMA/MMA ratio also leaded to a decrease in epoxy‐group density on the particle surface, since the reactivity of GMA was greater than that of MMA. Results of this work suggest that the influence of GMA/MMA mass ratio on the particle size and surface functionality of the nonporous particles was very significant. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1457–1463, 1999     

Preparation of cellulose nanocrystals and carboxylated cellulose nanocrystals from borer powder of bamboo

Carboxylated cellulose nanocrystals (CCN) and cellulose nanocrystals (CNC) were prepared from borer powder of bamboo by two different kinds of procedures: one-step approach with ammonium persulfate for CCN and two-step approach with sulfuric acid for CNC. The obtained samples were characterizated by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. The results show that the particles of CCN and CNC present spherical shape with diameters of 20–50 and 20–70 nm, respectively. The crystallinity of CCN and CNC is significantly improved after a series of chemical treatment, which is up to 62.75 and 69.84 %, respectively. The research indicates that the borer powder from bamboo could be an excellent raw material for manufacturing CNC in a low-cost and environmental-friendly way. Rational and sustainable utilization of the bamboo borer powder to develop new bioproducts holds great potential value for industry and offers many benefits and opportunities.     

Formation of hairy cellulose nanocrystals by cryogrinding

Cellulose - From a green chemistry perspective, cryogrinding of cellulose fibers conducted under mild conditions is introduced as a rapid, facile, and scalable methodology for the mechanochemical...     

Histidine-epoxy-activated sepharose beads embedded poly (2-hydroxyethyl methacrylate) cryogels for pseudobiospecific adsorption of human immunoglobulin G

The use of highly purified immunoglobulin became among the most powerful adopted strategies in therapeutic trials nowadays. Their role as immunomodulatory and anti-inflammatory agents has widened their scope of use. A novel continuous supermacroporous monolithic cryogels embedded with histidine-epoxy-activated-sepharose beads were synthetized as a new monolithic adsorbents for the separation of immunoglobulin G from human serum. The histidine-epoxy-activated-sepharose beads were embedded into the 2-hydroxyethyl methacrylate (HEMA) cryogels present in frozen aqueous solution inside a plastic syringe. The microstructure morphology of the cryogels was characterized by swelling measurement and scanning electron microscopy. The adsorption of human IgG on the histidine-epoxy-activated-sepharose beads pHEMA cryogels appeared to follow the Langmuir–Freundlich adsorption isotherm model. The maximum IgG adsorption was observed at 4°C and pH 7.4 and was found to be 26.95 mg/g of cryogel which is close to that obtained experimentally (24.49 mg/g). The cryogels were used for several adsorption-desorption cycles without any negligible decrease in their adsorption capacity.     

Synthesis,characterization and metal ion sorption studies of graft copolymers of cellulose with glycidyl methacrylate and some comonomers

To develop low-cost and environmentally friendly polymeric materials for enrichment, separation and remediation of metal ions from water, novel reactive graft copolymers based on cellulose extracted from pine needles were synthesized by grafting of poly(glycidyl methacrylate) alone and with comonomers acrylic acid, acrylamide and acrylonitrile by benzoyl peroxide initiation. Structural aspects of graft copolymers have been characterized by elemental analysis, FTIR, and solvent uptake behaviour. An attempt has been made to study sorption of Fe²⁺, Cu²⁺ and Cr⁶⁺ ions on candidate graft copolymers by an equilibration method and to investigate the structural aspects of graft copolymers and establish a relationship between the structural aspects of graft copolymers and metal ion uptake efficiency and selectivity.     

High performance poly (vinyl alcohol)/cellulose nanocrystals nanocomposites manufactured by injection molding

Polyvinyl alcohol (PVA)/cellulose nanocrystals (CNCs) compounds were successfully melt-processed by injection molding. During the processing, water was involved in the system as both the dispersion medium for CNCs and the plasticizer for PVA. Meanwhile, formamide was added to prevent the evaporation of water and to co-plasticize PVA. Thermal gravimetric analysis and differential scanning calorimetry indicated the melt processing window of PVA was expanded by 40 °C. Tensile tests showed that the mechanical properties of injection-molded samples were significantly improved with the addition of CNCs. The tensile strength of the composites increased from 32 to 58 MPa, and modulus increased from 175 to 1,252 MPa when 7 wt% CNCs was added. Moreover, the volume shrinkage of PVA nanocomposites upon drying as well as their water leaching rate could be remarkably reduced in the presence of CNCs.     

RAFT of sulfobetaine for modifying poly(glycidyl methacrylate) microspheres to reduce nonspecific protein adsorption

The minimization of nonspecific protein adsorption is a crucial step in the development of bioseparation processes, immunoassays, and affinity diagnostics. Among the numerous biomaterials, polyzwitterions are known to effectively suppress protein and cell adhesion. This article describes the formation of monodisperse polymer microspheres coated with polysulfobetaine with the aim to limit nonspecific adsorption of bovine serum albumin (BSA) as a model protein. In this process, 2‐μm poly(glycidyl methacrylate) (PGMA) microspheres were prepared by dispersion polymerization. To render the microspheres hydrophilic and biocompatible, [3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide (MPDSAH) was grafted from the surface by reversible addition‐fragmentation chain transfer (RAFT) polymerization. Elemental analysis of the modified microspheres revealed up to 20 wt % of poly{[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonimum hydroxide} (PMPDSAH). The microspheres were characterized in terms of particle size, morphology, and zeta potential. The amount of BSA nonspecifically adsorbed on the PMPDSAH‐modified microspheres decreased to half of that captured on the unmodified PGMA microspheres. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2273–2284     

Click chemistry-induced selective adsorption of cationic and anionic dyes using functionalized cellulose methacrylate hydrogels

Cellulose - In the preparation of hydrogels for removing dye pollutants from wastewaters, cellulose, a natural polymer, has become a popular raw material of late. In an effort to develop adsorbents...     

The role of hydrogen bonding in non-ionic polymer adsorption to cellulose nanocrystals and silica colloids

A piqued interest in nanocellulose has recently arisen due to the growing need to use sustainable and renewable materials in place of those that are derived from petrochemical resources. Although current commercial uses of nanocellulose remain limited, research over the past two decades demonstrates numerous applications including reinforcing agents in polymer and cement composites, coatings, foams, gels, tissue scaffolds, and rheological modifiers, amongst others. Because of the hydrophilic nature of nanocellulose many of the potential uses will likely be in water-based formulations or employ water-based processing methods. Thus understanding the interactions between nanocellulose and water-soluble polymers is critical. Although polyelectrolyte adsorption to cellulose is well understood, adsorption of non-ionic polymers is less clear, with hydrogen bonding often cited as a governing factor. Recent work suggests that in fact hydrogen bonding does not play a significant role in nanocellulose systems, and that non-ionic polymer adsorption is largely entropically driven. Herein we review current literature that investigates non-ionic polymer adsorption to cellulose nanocrystals (CNCs) and draw upon previous papermaking research to better understand the mechanisms involved. Additionally we analyze recent work that compares the adsorption of polyethylene glycol (PEG) to CNCs and fumed silica that provides further insight into this phenomenon. Our findings, along with current literature, suggest that hydrogen bonding does not significantly impact polymer adsorption in aqueous media despite reports to the contrary.     

Liquid crystalline thermosets based on anisotropic phases of cellulose nanocrystals

A new class of liquid crystalline thermosets (LCTs) was successfully produced containing lyotropic cellulose nanocrystals (CNCs) as the primary mesogenic component (up to 72 wt%) by the addition of non-mesogenic epoxy monomers. Cellulose-based LCTs were produced by totally aqueous processing methods and ultimately cured at elevated temperatures to produce ordered networks of ‘frozen’ liquid crystalline (LC) phases. Various degrees of birefringence were obtained via self-assembly of CNCs into oriented phases as observed by polarized optical microscopy and transmission electron microscopy. X-ray diffraction measurements highlighted the effects of texture of CNCs within LCT films compared to lyophilized CNCs. Cellulose-based LCT films uniquely exhibited thermo-mechanical properties of both traditional LCTs and LC elastomers, such as high elastic modulus (~1 GPa) under ambient conditions and low glass transition temperature (~?25 °C), respectively. The development of LCTs based on CNCs and aqueous processing methods provides a renewable pathway for designing high performance composites with ordered network structures and unique optical properties.     

All-cellulose nanocomposite fibers produced by melt spinning cellulose acetate butyrate and cellulose nanocrystals

Bio-based continuous fibers were prepared by melt spinning cellulose acetate butyrate (CAB), cellulose nanocrystals (CNC) and triethyl citrate. A CNC organo-gel dispersion technique was used and the prepared materials (2 and 10 wt% CNC) were melt spun using a twin-screw micro-compounder and drawn to a ratio of 1.5. The microscopy studies showed that the addition of CNC in CAB resulted in defect-free and smooth fiber surfaces. An addition of 10 wt% CNC enhanced the storage modulus and increased the tensile strength and Young’s modulus. Fiber drawing improved the mechanical properties further. In addition, a micromechanical model of the composite material was used to estimate the stiffness and showed that theoretical values were exceeded for the lower concentration of CNC but not reached for the higher concentration. In conclusion, this dispersion technique combined with melt spinning can be used to produce all-cellulose nanocomposites fibers and that both the increase in CNC volume fraction and the fiber drawing increased the mechanical performance.     

High performance liquid chromatographic determination of n-butyl glycidyl ether

A novel high-performance liquid chromatographic (HPLC) technique for the determination of n-butyl glycidyl ether (n-BGE) at concentrations down to 1 ppb (1 μg/liter) has been developed. This HPLC procedure is simple, highly sensitive, and rapid within the limits described.