Synthesis of ultrafine poly(styrene‐maleic anhydride) and polystyrene fibers by electrospinning

Fiber formation from atactic polystyrene (aPS) and alternating poly(styrene‐maleic anhydride) (PSMA) synthesized by free radical polymerization (AIBN, 90°C, 4 h) were investigated by electrospinning from various solutions. aPS was soluble in dimethylformamide (DMF), tetrahydrofuran (THF), toluene, styrene, and benzene, whereas PSMA was soluble in acetone, DMF, THF, dimethylsulfoxide (DMSO), ethyl acetate, and methanol. aPS fibers could be electrospun from 15 to 20% DMF and 20% THF solutions, but not from styrene nor toluene. PSMA, on the other hand, could be efficiently electrospun into fibers from DMF and DMSO at 20 and 25%, respectively. Few PSMA fibers were, however, produced from acetone, THF, or ethyl acetate solutions. Results showed that solvent properties and polymer–solvent miscibility strongly influenced the fiber formation from electrospinning. The addition of solvents, such as THF, generally improved the fiber uniformity and reduced fiber sizes for both polymers. The nonsolvents, however, had opposing effects on the two polymers, i.e., significantly reducing PSMA fiber diameters to 200 to 300 nm, creating larger and irregularly shaped aPS fibers. The ability to incorporate the styrene monomer and divinylbenzene crosslinker in aPS fibers as well as to hydrolyze PSMA fibers with diluted NaOH solutions demonstrated potential for post‐electrospinning reactions and modification of these ultrafine fibers for reactive support materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of poly(styrene‐co‐maleic anhydride) imidization on the miscibility and phase‐separation temperatures of poly(styrene‐co‐maleic anhydride)/poly(vinyl methyl ether) and poly(styrene‐co‐maleic anhydride)/ poly(methyl methacrylate) blends

The objective of this work was to study the miscibility and phase‐separation temperatures of poly(styrene‐co‐maleic anhydride) (SMA)/poly(vinyl methyl ether) (PVME) and SMA/poly(methyl methacrylate) (PMMA) blends with differential scanning calorimetry and small‐angle light scattering techniques. We focused on the effect of SMA partial imidization with aniline on the miscibility and phase‐separation temperatures of these blends. The SMA imidization reaction led to a partially imidized styrene N‐phenyl succinimide copolymer (SMI) with a degree of conversion of 49% and a decomposition temperature higher than that of SMA by about 20°C. We observed that both SMI/PVME and SMI/PMMA blends had lower critical solution temperature behavior. The imidization of SMA increased the phase‐separation temperature of the SMA/PVME blend and decreased that of the SMA/PMMA blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Fabrication and characterization of double‐network agarose/polyacrylamide nanofibers by electrospinning

This study focused on the preparation of electrospun cross‐linked double‐network (DN) of agarose/polyacrylamide (PAAm) nanofibers. The agarose formed the first‐network that was physical‐linked by the agar helix bundles. After UV‐irradiation, the chemically crosslinked PAAm was formed as the second network. The resulting cross‐linked DN agarose/PAAm nanofibers were characterized by scanning electron microscopy (SEM), contact angle, attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FT‐IR), thermogravimetric analysis (TGA), and tensile test. SEM analysis shows the agarose/PAAM nanofibers present with the thickness of 187 nm. Agarose/PAAm nanofibers were showing FT‐IR spectral peaks at ～1660, 1590, and 1070 cm^?1 indicating the presence of both agarose and polyacrylamide in the crosslinked DN Agarose/PAAm nanofiber sheet, it suggests the strong interaction and good compatibility between the two components. Agarose/PAAm nanofiber sheet was showing thermal stability close to the pure polyacrylamide. From the tensile test study, agarose/PAAm strength improved by 66.66% compared to the pure agarose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42914.     

Processing of continuous poly(amide‐imide) nanofibers by electrospinning

Continuous poly(amide‐imide) nanofibers were fabricated using a novel electrospinning method with rotating and re‐collecting cylindrical collectors. The nanofilaments were modified using various post‐treatments, i.e. glycerol treatment and thermal imidization under tension, for possible application as high‐performance reinforcements. Morphological and mechanical properties of continuous poly(amide‐imide) nanofibers prepared by the electrospinning process and various post‐treatments were measured. Severe adhesion between individual nanofibers within fiber bundles was inhibited through surface treatment of the electrospun nanofiber bundles by spraying with glycerol. The morphological and mechanical properties of the continuous poly(amide‐imide) nanofibers and thermal stability were improved using thermal imidization at high temperature under tension. The morphological and mechanical properties of the continuous electrospun nanofibers were improved significantly by post‐treatments after electrospinning because uniform and complete thermal imidization occurred through the core region of the nanofibers. Copyright © 2009 Society of Chemical Industry     

Swelling and hydrolytic degradation behaviour of pH‐responsive hydrogels of poly[(N‐isopropylacrylamide)‐co‐(methacrylic acid)] crosslinked by biodegradable polycaprolactone chains

BACKGROUND: Stimuli‐responsive hydrogels are typically obtained from non‐biodegradable monomers. The use of biodegradable crosslinkers can overcome this limitation. In this context, the main aim of this work was to use modified polycaprolactone as a crosslinker in the preparation of pH‐responsive hydrogels based on N‐isopropylacrylamide and methacrylic acid to give poly[(N‐isopropylacrylamide)‐co‐(methacrylic acid)] (P(N‐iPAAm‐co‐MAA)). RESULTS: Poly(caprolactone) dimethacrylate macromonomer was synthesized and successfully employed as crosslinker with various ratios in the synthesis of well‐known pH‐responsive hydrogels of P(N‐iPAAm‐co‐MAA). The swelling properties of these degradable hydrogels were investigated. They practically do not swell at pH = 2, but exhibit a very high swelling capacity in distilled water and in solutions of pH = 7. In addition, degradation studies at pH = 12 showed that the hydrolysis of the ester groups in the polycaprolactone chains produces, after a relatively short time, the total solubilization of the polymer chains. CONCLUSION: The hydrogels under study have certain characteristics that could make them good candidates for use as matrices in controlled drug delivery. On the one hand, they do not swell in acid pH solution (stomach conditions) but they swell extensively at neutral pH. On the other hand, they became rapidly water soluble following degradation. Copyright © 2009 Society of Chemical Industry     

Liquid crystallization of poly(styrene‐co‐maleic anhydride) induced by intermolecular hydrogen bonds

The liquid crystallization of general polymer (GP) with maleic anhydride in the main chain has been realized through molecular recognition and self‐assembly based on intermolecular hydrogen bonds. Poly[styrene‐co‐(N‐4‐carboxylphenyl)maleimide] (SMIBA) was synthesized by imidization and dehydration of Poly(styrene‐co‐maleic anhydride) (SMA) with p‐aminobenzoic acid (ABA) for use as an H‐bonded donor polymer. 4‐Methoxy‐4′‐stilbazole (MSZ) and 4‐nitro‐4′‐stilbazole (SZNO₂) were prepared as an H‐bonded acceptor. SMIBA was complexed with MSZ or SZNO₂ by slow evaporation from pyridine solution to form a self‐assembly, which exhibits the mesophase, while neither of the individual components is mesogenic. The phase diagrams of a variety of mixtures between of SMIBA and stilbazoles have been established using DSC and POM. They show complete miscibility and high thermal stability of the liquid crystalline phase over the whole composition range. The tuning of liquid crystalline properties was achieved by changing the composition of the mixture and involving it with a mixture of SZNO₂ and MSZ. IR measurements strongly support the existence of an H‐bonded complex between the carboxylic acid of SMIBA and the pyridine group of stibazoles. Unlike conventional side‐chain liquid crystalline polymer (SLCP), supramolecular SLCP with a lower molecular weigh polymeric donor has higher thermal stability of the liquid crystalline phase due to the microphase separated in the hydrogen bonding case. Liquid crystallization of GP, such as SMA, induced by hydrogen bonds, offers a new route to prepare functional material with controlled molecular architecture from readily accessible and simpler precursors. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 97–105, 1999     

Silver nanoparticle incorporated poly(l‐lactide‐co‐glycolide) nanofibers: Evaluation of their biocompatibility and antibacterial properties

The objective of this work is the fabrication of poly(l ‐lactide‐co‐glycolide) or PLGA (with LA/GA ratios of 50/50 and 75/25) nanofibers containing silver nanoparticles (AgNPs) by the method of electrospinning. The incorporation of AgNPs in PLGA was carried out in three different concentrations (1, 3, 6 w/w %).The electrospun nanofibers were evaluated for their morphology by scanning electron microscopy and their fiber diameters ranged between 487 and 781 nm. Integration of AgNPs within the fibers was verified by spectroscopy studies, while the mechanical properties of the developed fibers were found comparable to the mechanical properties of the human skin. Proliferation of human dermal fibroblasts (HDF) demonstrated minimal cytotoxicity on fibers containing 1 wt % and 3 wt % of AgNPs, while 6 wt % of AgNPs inhibited cell proliferation. Antimicrobial activity was studied using three different strains of Gram‐positive and Gram‐negative bacteria. Results of the HDF proliferation and antimicrobial studies showed that the electrospun PLGA75/25 containing 3 wt % AgNP can function as a suitable substrate for wound dressing, compared to the other scaffolds of this study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42686.     

Direct polymer reaction of poly(styrene‐co‐maleic anhydride): Polymeric imidization

Using direct polymer reaction of poly(styrene‐co‐maleic anhydride) (SMA), a synthesis of copolymer of styrene and N‐aryl succinimide (SMI) has been investigated. SMI copolymers were synthesized from SMA copolymers by a concerted two‐step reaction, which consisted of the condensation reaction (step 1) of SMA with aromatic amine to prepare a precursor, succinamic acid, for imide formation and the cyclodehydration reaction (step 2) of succinamic acid. In this article, the application of Searle's preparation method of N‐aryl or N‐alkyl maleimide to the direct polymer reaction for SMI was attempted. Compared with synthesis of monomeric imides, the imide formation in polymeric condition appeared to be a little more sensitive to the reaction condition. The optimum condition for maximum conversion was examined in terms of time, temperature, and the amount of reactants. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1187–1196, 1999     

Synthesis and superswelling behavior of carboxymethylcellulose–poly(sodium acrylate‐co‐acrylamide) hydrogel

In this paper, attention is paid to synthesis and swelling behavior of a superabsorbent hydrogel based carboxymethylcellulose (CMC) and polyacrylonitrile (PAN). The physical mixture of CMC and PAN was hydrolyzed in NaOH solution to yield hydrogel, CMC–poly(NaAA‐co‐AAm). During alkaline hydrolysis, the nitrile groups of PAN were completely converted to a mixture of hydrophilic carboxamide and carboxylate groups followed by in situ crosslinking of the grafted PAN chains. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR spectroscopy. The reaction variables affecting the swelling capacity of the hydrogel were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. Swelling measurements of the synthesized hydrogels in various chloride salt solutions indicated a swelling‐loss with increase in the ionic strength of the salt solutions. The pH of the various solutions also affected the swelling of the superabsorbent. Furthermore, the present hydrogels showed a pH‐reversible property. Finally, the swelling kinetics of synthesized hydrogels with various absorbent particle sizes was briefly examined. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of poly(styrene‐co‐hexylacrylate)/cellulose whiskers nanocomposites via miniemulsion polymerization

A stable aqueous nanocomposite dispersion containing cellulose whiskers and a poly(styrene‐co‐hexylacrylate) matrix was prepared via miniemulsion polymerization. We were able to prepare a stable dispersion with a 20 wt % solid content and a cellulose whiskers content ranging from 1 up to 5 wt % based on polymer content. To avoid particle agglomeration leading to coagulum formation, the addition of a low amount of reactive silane, i.e., methacryloxypropyl triethoxysilane revealed to efficiently stabilize the dispersion. The nanocomposite dispersion was characterized using dynamic light scattering, transmission electron microscopy, and atomic force microscopy. Films obtained by casting followed by water evaporation and particle coalescence were analyzed by differential scanning calorimetry, dynamic mechanical analysis, and tensile testing. At 5 wt % whiskers loading, an enhancement by 500% of the storage modulus above the glass transition was determined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Plasmon‐enhanced,two‐photon absorption in Schiff‐base‐modified poly(styrene‐co‐maleic anhydride)–gold nanocomposites

Poly(styrene‐co‐maleic anhydride) (SMA) is a synthetic copolymer with interesting thermal and membrane properties. Schiff bases are one of the most widely used organic compounds with chelating ligands having N, S, and O as donor atoms. A Schiff‐base‐modified SMA was synthesized by the reaction of the copolymer with salicylaldehyde thiosemicarbazone. Gold (Au) nanoparticles (NPs), synthesized by a citrate reduction method were used to prepare the polymer–Au nanocomposites. In this research, we explored and investigated the effects on the linear and nonlinear optical properties of the Schiff‐base‐modified SMA copolymer with the incorporation of Au NPs. Open‐aperture Z‐scan measurements were recorded for the polymer, modified polymer, and polymer–Au nanocomposites at 532 nm with an Nd:YAG laser with a repetition rate of 10 Hz and a pulse width of 5 ns. The results indicate that the addition of the Au NPs effectively enhanced the two‐photon absorption coefficients of the polymer and, thereby, provided a platform for the development of nonlinear optical devices with good optical‐limiting properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45377.     

High‐efficiency recovery of rare earth ions by hydrolyzed poly(styrene‐co‐maleic anhydride)

Hydrolyzed poly(styrene‐co‐maleic anhydride) (PSMA) as a high‐efficiency adsorbent is used for recovering La³⁺, Eu³⁺, Tb³⁺, and Yb³⁺ from the simulate wastewater of bastnaesite leach liquor. The pseudo‐first‐order and pseudo‐second‐order models are used to fit adsorption data in the kinetic studies and the results show good correlation with the pseudo‐second‐order model. The Langmuir model is found to fit for the isotherm data of all the rare earth ions (RE³⁺) and the maximum adsorption capacity of hydrolyzed PSMA is 285.79, 301.92, 305.46, and 336.65 mg g^?1 at 298 K for La³⁺, Eu³⁺, Tb³⁺, and Yb³⁺, respectively. The adsorption could be conducted in at pH 6.0 and the equilibrium is fast established in 30 min. Competition from coexisting ions (Ca²⁺, Mg²⁺) was proved to be insignificant. Moreover, the spent adsorbent could be well regenerated and kept above 80% of adsorption efficiency at the end of the fifth cycle. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43676.     

Preparation and characterization of graphene oxide/poly(vinyl alcohol) composite nanofibers via electrospinning

Graphene oxide (GO) was well dispersed in poly(vinyl alcohol) (PVA) diluted aqueous solution, and then the mixture was electrospun into GO/PVA composite nanofibers. Electron microscopy and Raman spectroscopy on the as‐prepared and calcined samples confirm the uniform distribution of GO sheets in the nanofibers. The thermal and mechanical properties of the nanofibers vary considerably with different GO filler contents. The decomposition temperatures of the GO/PVA composite nanofiber dropped by 38–50°C compared with pure PVA. A very small loading of 0.02 wt % GO increases the tensile strength of the nanofibers by 42 times. A porous 3D structure was realized by postcalcining nanofibers in H₂. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and properties of a novel superabsorbent polymer composite from microwave irradiated waste material cultured Auricularia auricula and poly (acrylic acid‐co‐acrylamide)

A novel superabsorbent polymer composite was successfully synthesized from waste material cultured Auricularia auricula (WMCAA) and poly (acrylic acid‐co‐acrylamide) (P(AA‐co‐AM)) using microwave irradiation. Optimal synthesis conditions were determined by investigating the water absorbency of the superabsorbent composite. The effects associated with weight ratios of WMCAA, acrylamide (AM) monomers, initiators, and acrylic acid (AA) crosslinkers, as well as the degree of neutralization of AA were examined. The maximum water absorbencies were found to be 1548 g/g (distilled water) and 72 g/g (0.9% NaCl solution). Fourier transform infrared spectroscopy (FTIR) was applied to determine the molecular structure of the superabsorbent composite, and scanning electron microscopy (SEM) was used to demonstrate the characteristic compact and porous structure of the material. Further studies conducted via transmission electron microscopy (TEM) revealed the formation of a novel interpenetrating polymer network structure. Thermogravimetry/differential thermal (TG/DTG) analysis demonstrated improved thermal stability in the composite material compared with WMCAA. Additionally, high water absorption rates observed in the polymer during the swelling process indicated first‐order kinetics. The water absorption and adsorption of the superabsorbent composite were studied in a variety of fertilizer solutions, revealing an indirect relationship between water absorbing ability and fertilizer concentration. Conversely, a direct relationship was observed between absorbed fertilizer and fertilizer concentration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3674–3681, 2013     

Covalent immobilization of β‐galactosidase onto electrospun nanofibers of poly (AN‐co‐MMA) copolymer

Immobilization of β‐galactosidase in poly (acrylonitrile‐co‐methyl methacrylate) poly (AN‐co‐MMA) Nanofibers was studied by electrospinning, and a spacer‐arm i.e., (Polyethyleneimine (PEI)) was covalently attached by the reaction of carbonyl groups of Poly (AN‐co‐MMA) nanofibers. β‐galactosidase was then covalently immobilized through the spacer‐arm of the Poly (AN‐co‐MMA) nanofibers by using glutaraldehyde (GA) as a coupling agent. Nanofibers mode of interaction was proven by FTIR and thermal gravimetric analysis and supported by morphological changes recognized through SEM examination. Factors affecting the modification process such as PEI concentration, reaction time, and reaction temperature have been studied. Its influence on the amount of coupled PEI was consequently correlated to the changes of the catalytic activity and the retained activity of immobilized enzyme, the main parameters judging the success of the immobilization process. Evidences of Poly (AN‐co‐MMA) nanofibers modification were extracted from morphological changes recognized through SEM examination. The maximum activity (V_max) and michaelis constant (K_m) of immobilized enzyme were found to be 8.8 μmole/min mg protein and 236.7 mM, respectively. Stabilities of the immobilized β‐galactosidase were obviously improved. The optimum temperature for β‐galactosidase immobilized on the spacer‐arm attached nanofiber was 5°C higher than that of the free enzyme and was also significantly broader. The immobilized β‐galactosidase had better resistance to temperature inactivation than did the free form. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of blending on the molecular dynamics of highly interacting binary polymer blends of poly(methyl methacrylate) and poly[styrene‐co‐(maleic anhydride)]

The molecular dynamics and miscibility of highly interacting binary polymer blends of poly(methyl methacrylate) (PMMA) and poly[styrene‐co‐(maleic anhydride)] random copolymer with 8 wt% maleic anhydride content (SMA) were investigated as a function of composition over a wide range of frequency (10^?2–10⁶ Hz) at different constant temperatures (30–160 °C). Only one common glass relaxation process (α‐process) was detected for all measured blends, and its dynamics and broadness were found to be composition dependent. The existence of only one common α‐relaxation process located at a temperature range between those of the pure polymer components indicated the miscibility of the two polymer components over the entire range of composition. The miscibility was also confirmed by measuring the glass transition temperatures of the blends, T_g, using differential scanning calorimetry. The composition dependence of T_g of the blends showed a positive deviation from the linear mixing rule and well described by the Gordon–Taylor–Kwei equation. The relaxation spectrum of the blends was resolved into α‐ and β‐relaxation processes using the Havriliake–Negami (HN) equation and ionic conductivity. The dielectric relaxation parameters obtained from HN analysis, such as broadness of relaxation processes, maximum frequency, f_max, and dielectric strength, Δ? (for the α‐ and β‐relaxation processes), were found to be blend composition dependent. The kinetics of the α‐relaxation process of the blends were well described by the Meander model, while an Arrhenius‐type equation was used to evaluate the molecular dynamics of the β‐relaxation process. Blending of PMMA and SMA was found to have a considerable effect on the kinetics and broadness of the β‐relaxation process of PMMA, indicating that the strong interaction and miscibility between the two polymer components could effectively change the local environment of each component in the blend. © 2013 Society of Chemical Industry     

Kinetics and simulation of the imidization of poly(styrene‐co‐maleic anhydride) with amines

The imidization of poly(styrene‐co‐maleic anhydride) with amines may improve some of its end‐use properties. The objective of this study was to examine the mechanism and kinetics with aniline (ANL) as an amine of the preparation of poly(styrene‐co‐N‐phenyl maleimide). The reaction was carried out in a tetrahydrofuran solution at 25–55°C and in an ethylbenzene solution at 85–120°C. The extent of the reaction was determined by conductance titration, a new and simple method. Two consecutive reactions were involved in the imidization: ring opening to produce an acido‐amide group and ring closing to form a corresponding imide group. The imidization rate was greatly influenced by the reaction temperature and the molar ratio of ANL to the anhydride. A model for the imidization kinetics over a wide range of reaction temperatures and concentration ranges was developed and validated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2744–2749, 2006     

Nonlinear phase‐separation behavior of poly(methyl methacrylate)/poly(styrene‐co‐maleic anhydride) blends

The nonlinear phase‐separation behavior of poly(methyl methacrylate)/poly(styrene‐co‐maleic anhydride) (PMMA/SMA) blends over wide appropriate temperature and heating rate ranges was studied using time‐resolved small‐angle laser light scattering. During the non‐isothermal process, a quantitative logarithm function was established to describe the relationship between cloud point (T_c) and heating rate (k) as given by T_c = Alnk + T₀, in which the parameter A, reflecting the heating rate dependence, is much different for different compositions due to phase‐separation rate and activation energy difference. For the isothermal phase‐separation process, an Arrhenius‐like equation was successfully applied to describe the temperature dependence of the apparent diffusion coefficient (D_app) and the relaxation time (τ) of the early stage as well as the late stage of spinodal decomposition (SD) of PMMA/SMA blends. Based on the successful application of the Arrhenius‐like equation, the related activation energies could be obtained from D_app and τ of the early and late stages of SD, respectively. In addition, these results indicate that it is possible to predict the temperature dependence of the phase‐separation behavior of binary polymer mixtures during isothermal annealing over a range of 100 °C above the glass transition temperature using the Arrhenius‐like equation. © 2012 Society of Chemical Industry     

Controlled DNA interpolyelectrolyte complex formation or dissociation via stimuli‐responsive poly(vinylamine‐co‐N‐vinylisobutylamide)

Poly(vinylamine‐co‐N‐vinylisobutylamide) or poly(VAm‐co‐NVIBA) was evaluated for its ability to stabilize double‐stranded DNA (dsDNA) with the controlled formation or dissociation of polyion complexes. The poly(VAm‐co‐NVIBA) copolymer consists of the cationic poly(vinylamine) (VAm) that electrostatically binds to the anionic DNA and the thermally responsive poly(N‐isobutylamide) (NVIBA) that helps limit the strength of the electrostatic interaction and prevents the alteration of the DNA helical structure. Agarose gel electrophoresis showed the successful complexation between dsDNA and poly(VAm‐co‐NVIBA). Moreover, DNA was released from the complex at 65 °C, but not at 25 °C. Thus, the NVIBA component in the copolymer played an important role in controlling the process of complex formation or dissociation according to the pH and temperature. The results showed that the molecular design of polycations with a thermoresponsive part is a potential strategy to allow the controllable formation and dissociation of the copolymer/dsDNA complex while avoiding changes to the DNA helical structure. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43852.     

Characterization and mechanical properties of ultraviolet stimuli‐responsive functionalized cellulose nanocrystal alginate composites

The poor mechanical properties of alginate when exposed to aqueous solution have been a problem plaguing researchers within the biomedical field. In order to be able to improve the mechanical properties in a systematic manner functionalized cellulose nanocrystals (CNCs) were added to alginate and UV‐induced crosslinked following an azo‐initiated free radical polymerization. CNCs were functionalized with 4‐pentenoic acid (PA‐g‐CNCs) using a simple, environmentally friendly solvent‐free esterification. The dimensional and crystallinity properties of PA‐g‐CNCs remained unchanged following esterification. Thermogravimetric analysis, Fourier transform infrared spectroscopy, and ¹³C nuclear magnetic resonance indicated that 4‐pentenoic acid was present on the surface of CNCs through bulk analysis. These PA‐g‐CNCs were then used in the creation of composites with an azo‐initiator to induce UV‐dependent crosslinking for the improvement of the mechanical properties of alginate. It was shown that the properties of alginate can be enhanced with the addition of functionalized CNCs to nanocomposites in mechanical testing in wet and dry conditions. These results suggest that the addition of PA‐g‐CNCs and crosslinking by UV‐dependent free radical polymerization improves the performance of alginate when tested in dry conditions, but without any apparent dependence to azo‐initiated crosslinking when exposed to water in regards to mechanical properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45857.