Free-radical Crosslinking Polymerization Research Articles

Judd-Ofelt analysis and temperature sensing properties of polyethylmethacrylate (PEMA) networks doped with CdNb2O6: Er3+/Yb3+ phosphors

Research on the sensitivity of temperature measurements and optical thermometry involving rare earth ions has been an area of interest in the field of photonics and materials science. Introducing polymer networks as a new host material has an important role due to their properties including a versatile and stable environment for rare earth ions and rapid response in temperature detection. In this work, linear and crosslinked polyethylmethacrylate (PEMA) networks doped with Er3+/Yb3+ (1.5 mol % Er3+, 2 mol% Yb3+) synthesized by free-radical crosslinking polymerization with 0.1 EMA (weight %) at 60 °C were used to investigate direct and indirect optical bandgap energies and Urbach energy from UV–Visible spectra. The Judd-Ofelt (JO) approach was employed to analyze parameters Ωt (t = 2,4,6), spontaneous transition probabilities (Α), branching ratios (β) and radiative lifetimes (τ) as a function of linear and crosslinked PEMA doped nano-crystalline CdNb2O6: Er3+/Yb3+. The stimulated emission cross-sections of the transitions 2H11/2⟶4I15/2, 2S3/2⟶4I15/2 and 2F9/2⟶4I15/2 of Er3+/Yb3+ were calculated by two different methods; Fuchtbauer-Ladenburg formula and modified theory, respectively. The gain bandwidth cross-section product for the 2H11/2⟶4I15/2 was found to be 162.06. 10−28cm3, 260.94. 10−28cm3 and 461.20. 10−28cm3 of Er3+/Yb3+ embedded in linear, low and high crosslinked PEMA samples, respectively. JO parameters and stimulated emission cross-sections increased; therefore, radiative lifetimes decreased by increasing crosslinking content. In addition, the temperature dependence of upconversion (UC) luminescence was monitored under 975 nm excitation. The fluorescence intensity ratio (FIR) method examined the temperature sensing under two thermally coupled levels at 525 and 548 nm. The maximum sensitivities obtained from the FIR technique within the 300–650 K temperature range shifted to lower temperatures with increasing crosslinker content. Hence, linear and crosslinked polymer hosts doped rare-earth ions can be candidates for remote temperature sensors across various fields.

Dual-responsive, highly bacteriostatic and swellable chitosan-based hydrogels loaded with 5-fluorouracil for sustainable release

In this work, a dual-responsive hydrogel for sustainable release of drug was prepared using chitosan grafted with PBA as substrate to form semi-interpenetrating polymer networks (S-IPN) via free-radical crosslinking polymerization of acrylic acid in the presence of MBAA as a crosslinker and KPS as an initiator as well as Fe3+.ions introduced. The results from comprehensive characterization indicated that the as-prepared hydrogel possesses cavity structure with the pores of varying sizes, thus facilitating the accommodation of 5-fluorouracil as a model drug. In addition, the swelling behavior of the hydrogels in different pH buffers and glucose solutions was also investigated. As expected, the prepared hydrogels are pH and glucose responsive due to PAA and phenylboronic acid incorporated into the hydrogel, which enables the slow or sustainable release of drug. Moreover, the release processes were fitted with various kinetic models whereas the release was better described by Korsmeyer-Peppas model or the drug release is mainly governed by the release mechanism of the hydrogel is primarily driven by Fickian diffusion from a mechanical point of view. Hydrogel loaded with drug was found to have good antibacterial effects against E. coli and S. aureus, leading to the potential for various medical-related applications.

Decoding Elasticity Build-Up and Network Topology in Free-Radical Cross-Linking Polymerization: A Combined Experimental and Atomistic Approach

Decoding Elasticity Build-Up and Network Topology in Free-Radical Cross-Linking Polymerization: A Combined Experimental and Atomistic Approach

A REVIEW OF NANOGELS AS NOVEL DRUG DELIVERY SYSTEMS

The term “nanogel” refers to highly cross-linked hydrogels with a size between 20 and 200 nm. Due to their tiny size, they have higher penetration and greater drug-loading capacity. They release the medication using mechanisms such as photochemical internalization, volume transition, pH responsiveness, thermo sensitive, and photo isomerization. They can be categorized according to whether they respond to stimuli or not as well as the kind of links that are present in the gel structure’s network chains. Using photolithography, modified pollutants, and emulsions, one can create nanogel. Reverse microemulsion polymerization, inverse mini-emulsion polymerization, and the free radical cross-linking polymerization method are all examples of polymerization. Cancer, diabetes, inflammation, and bone regeneration are just a few conditions that can be treated with nanogels. The cutting-edge medication delivery technology for both hydrophilic and hydrophobic drugs is nanogels. This article focuses on the historical data regarding herbal nanogels, which have high patient compliance, delivery rate, and efficacy when used to treat various illnesses. The topic of stimulus-responsive nanogels, including pH-and temperature-responsive systems, is also covered.

Optical fiber temperature sensor based on Fabry-Perot interferometer with photopolymer material

We propose and demonstrate a new method for fabricating a Fabry-Perot interferometer sensor. This work uses photopolymerizable materials to construct Fabry-Perot interference structures, making the fabrication process more straightforward and less expensive than other methods. We put a 532 nm laser into the single-mode fiber (SMF) to fabricate photopolymer probes on the face of the fiber. The end face of the probe and the end face of the SMF will form a Fabry-Perot interferometer (FPI). At the same time, to demonstrate its ability to be easily fabricated for sensing various parameters, we incorporated PDMS into the photopolymer material and conducted temperature sensing experiments. The relationship between the concentration of the PDMS and the temperature sensitivity is studied. The experimental results show that the higher the concentration of PDMS, the higher the temperature sensitivity. In the case of ensuring other capabilities, the sensitivity has reached − 1.18 nm/°C in the temperature range of 20–110 °C. We propose and demonstrate a new method for fabricating a Fabry-Perot interferometer sensor. This work uses photopolymerizable materials to construct Fabry-Perot interference structures, making the fabrication process more straightforward and less expensive than other methods. We put a 532 nm laser into the single-mode fiber (SMF) to fabricate photopolymer probes on the face of the fiber. The end face of the probe and the end face of the SMF will form a Fabry-Perot interferometer (FPI). At the same time, to demonstrate its ability to be easily fabricated for sensing various parameters, we incorporated PDMS into the photopolymer material and conducted temperature sensing experiments. The relationship between the concentration of the PDMS and the testing sensitivity is studied. The experimental results show that the higher the concentration of PDMS, the higher the testing sensitivity. In the case of ensuring other capabilities, the sensitivity has reached − 1.20507 nm/°C in the temperature range of 20–80 °C. • This work uses a free-radical photopolymerizable formulation is sensitive between 450 and 550 nm and converted through a free-radical cross-linking polymerization under green light irradiation, which can easily fabricate waveguide structure on the fiber end face. • This photopolymeriazble formulation allows us to add different sensitive materials for the purpose of making different sensors. • We add PDMS into the photopolymeriazble formulation to measure the temperature. In the temperature range of 20–80 °C, the sensitivity reached − 1.20507 nm/°C and demonstrates good stability.

The effect of crosslinker contents on the up-conversion luminescence properties of CdNb2O6: Er3+ powders embedded in the polyethylmethacrylate (PEMA) networks

In this work, CdNb2O6:Er2O3(1.5 mol% Er3+) powders doped with Er3+ were embedded in bulk linear polyethylmethacrylate (PEMA) and also as a novelty embedded in bulk PEMA crosslinked networks (gels) with four different crosslinker contents by free-radical crosslinking polymerization with 0.1 EMA (weight %) at 60 °C. The Er3+ ions structures embedded in bulk linear PEMA and PEMA gels were investigated by the X-ray diffraction (XRD) technique. The crystalline particle size was found using Pielazsek particle distribution and the Scherrer equation. The average of the crystalline particle sizes was found to be decreasing from 75 nm to 12.50 nm by increasing the crosslinker contents therefore, it was shown that the distribution became more uniform. The morphology of CdNb2O6: Er3+ embedded in PEMA gel samples was monitored by scanning electron microscopy (SEM). The functional groups on linear PEMA and PEMA gels samples were monitored by Fourier transform infrared (FT-IR) spectra, and the results were consistent with XRD results. The optical properties of polymer samples were investigated by measuring luminescence spectra at room temperature. The doped Er3+ ion excited with a 975 nm diode laser achieved the up-conversion (UC) emissions by involving two or three-photon absorptions in the visible region. The effects of crosslinker contents on the UC emission, color tuning, and color quality parameters were observed. As the crosslinker contents increased, the UC emission intensities increased due to increasing the distance between Er3+- Er3+ ions. The change in color coordinates was also observed by increasing crosslinker content. The chromaticity diagram over the increasing power of the excitation source visualized the tunability of the emitted color. The improvement of the color purity was observed as a function of crosslinker concentration.

Polydopamine-heparin complex reinforced antithrombotic and antimicrobial activities of heparinized hydrogels for biomedical applications

Large-scale fabrication of heparinized hydrogel could be accomplished by free-radical crosslinking polymerization (FRCP), whilst its bioactivity is often partially lost. Heparinized hydrogel based implantable medical devices, therefore, frequently encounter the compelling problems of thrombosis and microbial infection. In this study, a facile FRCP approach was proposed to fabricate heparinized hydrogels by preforming polydopamine-heparin (PDA-HEP) complex, which bypassed the steps of heparin functionalization and effectively preserved the function of heparin in the meantime. Compared with heparin mixed hydrogels, heparin in PDA-HEP complex composite hydrogels augmented the antimicrobial activity of PDA by enhancing the combined bactericidal action of cations and reactive oxygen species (ROS), while still maintaining its anticoagulant function. Since its integration of extremely low hemolysis rate, remarkable anticoagulation property and efficient bactericidal performance, we believe that this universal method of preparing heparinized hydrogels based on PDA-HEP complex will speed up the versatile application of hydrogel implants in clinical medicine.

Sulfasalazine/Nimesulide dual-loaded halloysite based poly (sulfobetaine methacrylate) hydrogels: Development and drug release characteristics

Co-administration of two or more drugs has recently become a viable option for treating a variety of diseases, including rheumatoid arthritis (RA). A simple method was used to encapsulate drugs with different solubilities in the same matrix. The internal space of halloysite nano tubes was increased by acid treatment prior to drug loading. Nimesulide (NIMS, an NSAID) and sulfasalazine (SLZ, a DMARD) were loaded into the halloysite lumen either individually or in combination. The halloysite-drug conjugates were then incorporated with poly [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (PSBMA) matrix during free radical crosslinking polymerization. Different kinetic models (zero-order, first-order, Higuchi, and Korsmeyer-Peppas) were studied to fit single and combined drug release kinetics. When compared to its sole drug formulation, the combined drug release kinetics demonstrated different release mechanisms. Both drugs were released more slowly as pH decreased, owing to their decreasing solubility. Cell culture tests revealed that the composite hydrogel was not cytotoxic.

Colloidal dispersion gels for in-depth permeability modification

In this study, we describe the synthesis, characterization and evaluation of colloidal dispersion gels (CDGs) to be used as in-situ fluid diversion. The chemical stability of CDGs was improved by modifying the polymer mixture. The CDGs were synthesized by free radical crosslinking polymerization using 2-acrylamido-2-methylpropane sulfonic acid (AMPS), Acrylic acid (AAc), partially hydrolyzed polyacrylamide (HPAM) and chromium triacetate crosslinker. The effect of crosslinker/polymer concentration, salinity, gelation time, rheological behavior, particle size distribution of CDGs, also their thermo-chemical stabilities and resistance/residual resistance factor (RRF) were investigated.

Unusual swelling of acrylate based crosslinked polymer networks in linear primary alcohols: Experimental and modeling aspects

The present investigation focuses on analysis of swelling behavior of systems composed of linear primary alcohols and photo-chemically crosslinked poly (butyl prop-2-enoate) (PABu). For this purpose, reactive blends composed of monofunctional (n-ABu) and difunctional (1-prop-2-enoyloxyhexyl prop-2-enoate) monomers as well as a standard photoinitiator were exposed to ultraviolet-visible (UV–vis) irradiation to induce free radical crosslinking polymerization. Experimental swelling studies of the obtained optically transparent PABu networks in methanol, ethanol, propan-1-ol, butan-1-ol, pentan-1-ol, hexan-1-ol and heptan-1-ol were performed by gravimetric sorption measurements. Among the various models available to rationalize the swelling kinetics of these PABu-alcohol systems, the second order approach was found to agree well with the experimental data.In particular it was observed that swelling properties strongly depend on the length of the linear alkyl chain of the primary alcohols. Swelling of PABu network at equilibrium increases from methanol to butan-1-ol where it reaches a maximum and subsequently decreases from butan-1-ol to heptan-1-ol. To understand this unusual behavior, polymer-solvent solubility parameters were considered, which could not account for the swelling maximum detected in the case of butan-1-ol. Molecular simulations performed on model systems composed of a linear primary alcohol molecule set and a reproduced PABu network revealed that their mutual interaction energy times the molar mass of the alcohol show a trend very similar to that of the observed swelling behavior.

Mechanical Properties and Moisture Transport Behavior of Acid-Sensitive Hydrogels

Thin hydrogel films containing the acid sensitive cross-linker 2,5-dimethyl-2,5-hexanediol dimethacrylate (DHDMA) were synthesized as part of a larger project to create protective layers against chemical and biological (CB) threats. In order to operate efficiently as fabric coatings, the mechanical and moisture vapor transport properties of these materials must be understood. The hydrogels were composed primarily of poly(ethylene glycol) dimethacrylate (PEGDMA) and 2-hydroxyethyl methacrylate (HEMA) and were prepared by free radical cross-linking polymerization. The influence of different compositions of DHDMA, PEGDMA, and HEMA on the moisture vapor transmission rate (MVTR), mechanical properties, and swelling properties of PEGDMA/DHDMA/HEMA copolymer hydrogels has been investigated. The characterization by Fourier transform infrared (FTIR) spectroscopy confirmed the presence of all monomers used in the gel structure. The hydrogels showed high MVTR, which are comparable to the widely accepted breathable m...

Removal of Heavy Metal Water Pollutants (Co2+ and Ni2+) Using Polyacrylamide/Sodium Montmorillonite (PAM/Na-MMT) Nanocomposites

Nanocomposites composed of polyacrylamide and nanoclay were synthesized via free-radical cross-linking polymerization and used to adsorb Co2+ and Ni2+ ions from water. The polyacrylamide (PAM)/sodium montmorillonite (Na-MMT) nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy to confirm the interaction between montmorillonite and the polymer matrix. The effects of pH and heavy metal ion concentration on the adsorption capacity of PAM/Na-MMT were evaluated to determine suitable operating conditions for further experiments. Batch adsorption experimental data were fitted to Langmuir and Freundlich models, which provided information about the adsorption mechanism and the adsorbent surface. The highest Ni2+ removal yield was found to be 99.3% using the 2:1 (w/w) nanocomposite at pH 6 in 100 ppm of Ni2+ solution. The Co2+ removal yield was 98.7% at pH 6 in 60 ppm of Co2+ solution using the 4:1 (w/w) nanocomposite. These results were higher than those obtained by polyacrylamide and nanoclay under the same conditions (removal yield between 87.40 and 94.50%), indicating that PAM/Na-MMT nanocomposites remove heavy metal water pollutants more efficiently and can be used as a novel adsorbent for further industrial applications.

Impact of the Mechanical Properties of a Functionalized Cross-Linked Binder on the Longevity of Li-S Batteries.

One of the very challenging aspects of Li-S battery development is the fabrication of a sulfur electrode with high areal loading using conventional Li-ion binders. Herein, we report a new multifunctional polymeric binder, synthesized by the free-radical cross-linking polymerization of [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETMAC) and ethylene glycol diacrylate (EGDA) to form poly(AETMAC- co-EGDA), that not only helps to confine the soluble polysulfide species but also has the desired mechanical properties to allow stable cycling of high-sulfur loading cathodes. Through a combination of spectroscopic and electrochemical studies, we elucidate the chemical interactions that inhibit polysulfide shuttling. We also show that extensive cross-linkage enables this polymeric binder to exhibit a low degree of swelling as well as high tensile modulus and toughness. These attributes are essential to maintain the architectural integrity of the sulfur cathode during extended cycling. Using this material, Li-S cells with a high-sulfur loading (6.0 mg cm-2) and a low-intermediate electrolyte/sulfur ratio (7 μL:1 mg) achieve an areal capacity of 5.4 mA h cm-2 and can be (dis)charged for 300 cycles with stable reversible redox behavior after the initial cycles.

Development, characterization, swelling, and network parameters of amino acid grafted guar gum based pH responsive polymeric hydrogels

This study includes the synthesis of graft copolymer (GG-g-PAPA) from N-Acryloyl-L-phenylalanine (APA) and guar gum through free radical polymerization. Then, the novel pH sensitive GG-g-PAPA-cl-(PHEA-co-PAMPS) [GGAH] polymeric hydrogels were synthesized by employing free radical cross-linking polymerization using graft copolymer, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and 2-hydroxy ethyl acrylate (HEA). The GGAH hydrogels were characterized using FTIR and SEM. Swelling studies of GGAH hydrogels were performed in distilled water, pH 1.2, and pH 7.4 solutions. The network and swelling kinetic parameters of GGAH hydrogels are also calculated.

A phenomenological approach for structure-property relationship of polybasic cryogels based on n-alkyl methacrylate esters: Anion-specific effect on swelling kinetics and elasticity

Stimuli-responsive weakly cationic cryogels and hydrogels of poly(N,N-dimethylaminoethyl methacrylate) PDMAEMA with diethyleneglycol dimethacrylate (DEGDMA) as crosslinking agent have been synthesized at various gel-preparation concentrations as new alternative ion-responsive networks via free radical crosslinking (cryo)polymerization conducted at different temperatures. The influence of the reaction parameters; the gel-preparation concentration and the polymerization temperature on the equilibrium swelling degree, swelling kinetic parameters and basic structural properties of PDMAEMA cryogels (Cgs) and hydrogels (Hgs) were investigated. The specific-anion response of prepared PDMAEMA gels to a range of potassium salt solutions; KCl, KBr and KI was evaluated in the range of ionic-strength between 10−5 M and 1.0 M. To determine the associative interactions between PDMAEMA network-surfactant species and the optimum conditions necessary to induce surfactant binding, the extent of swelling in aqueous medium was studied in the presence of different types of surfactants; CTAC, CTAB and SDS. The oscillating swelling processes of both PDMAEMA Cgs and Hgs followed the Schott second order dynamic equation. The water diffusion followed by non-Fickian mechanism with anomalous behavior was alternatively viewed as the probe to understand the influence of the gel composition and the gel-preparation concentration on the microstructure of homopolymeric polybasic gels. The specific ion-responsivity and ability of binding surfactant species give these intelligent PDMAEMA Cgs and Hgs wide potential in bio-sensing applications.

Preparation and characterization of vinylimidazole-based polymer monolithic stationary phases for reversed-phase and hydrophilic interaction capillary liquid chromatography

In this study, we applied 1-vinylimidazole (VIM) as the functional monomer to prepare a series of VIM-based monolithic stationary phases for both reversed-phase and hydrophilic interaction capillary liquid chromatography (LC) using various dimethacrylates (EDMA: ethylene dimethacrylate; HDDMA: 1,6-hexanediol dimethacrylate; DDDMA: 1,10-decanediol dimethacrylate) as cross-linkers. With a simple thermally initiated free-radical cross-linking polymerization process, VIM-based monolithic stationary phases have been successfully prepared. The porosity, permeability, and column efficiency of synthesized VIM-based monolithic stationary phases were characterized. With similar total porosity (85–90%), the VIM-HDDMA monoliths showed the lowest permeability among the three sets of VIM-based stationary phases. Various sets of non-polar (alkyl benzenes and polycyclic aromatic hydrocarbons) and polar analytes (phenol derivatives and amphenicol antibiotics) were applied as model compounds to further investigate the retention behavior of the VIM-based monolithic stationary phases for reversed-phase capillary LC analysis using selected VIM-based monolithic columns. While a mixture of organic acids was employed to perform HILIC analysis using the selected VIM-based monolithic columns. The separation selectivity and retention behavior of the VIM-based monolithic stationary phases were compared to those obtained using three previously prepared alkyl methacrylate-based monolithic columns. Strong retention and good resolution of polar analytes (such as phenol derivatives, amphenicol antibiotics, and organic acids) were observed using the selected VIM-based monolithic columns. The strong retention and good resolution might be attributed to the additional hydrogen-bonding between the hydrogen-donating analytes and the hydrogen-accepting imidazolium functionality on the VIM-based stationary phase. The applicability for both reversed-phase and HILIC capillary LC analysis has also been demonstrated using the selected VIM-based monolithic columns.

Nanocellulose/Poly(2-(dimethylamino)ethyl methacrylate)Interpenetrating polymer network hydrogels for removal of Pb(II) and Cu(II) ions

Interpenetrating network (IPN) hydrogels based on nanofibrillated cellulose (NFC) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA)were prepared via crosslinking free radical polymerization. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA) confirmed the formation hybrid network of NFC and PDMAEMA. The IPN hydrogels possess uniform pore structure and high porosity (>97%). The specific surface area and compressive strength were higher than 82m2g−1 and 1.26kPa, respectively. Water swelling experiments showed that the IPN hydrogels were both pH-sensitive and temperature-sensitive. The swelling of hydrogels was limited at high temperature and in neutral medium. There was an increase in the swelling ratio as the NFC content increased. Adsorption kinetic and thermodynamics studies of Cu(II) and Pb(II) explained pseudo-second-order equation and Langmuir model (R2>0.99) as the best fit. The maximum adsorption capacities of Cu(II) and Pb(II) according to Langmuir model were 217.39mg/g and 81.96mg/g, respectively. The good adsorption performance can be attributed to the chelation of tertiary amine groups and the ion-exchange of carboxyl groups.

Tunable elasticity and thermodynamic parameters of hydroxypropyl methacrylate‐based gels with varying extents of monomer concentration: Statistical mechanics treatments of physical observations

ABSTRACTThe present article reports the scaling laws relating the preparation conditions with the equilibrium swelling degree and the crosslinking density of a new family of hydroxyl functional hydrogels (Hgs) prepared by free radical crosslinking polymerization of hydroxypropyl methacrylate (HPMA) in aqueous solution with tetraethylene glycol dimethacrylate (TEGDMA) as crosslinker. For comparison of physical properties, chemical and mechanical stability, HPMA cryogels (Cgs) were also prepared using the cryotropic gelation technique by conducting the gelation reactions at subzero temperatures. The measurements of the equilibrium swelling degree and the elastic properties of poly(hydroxypropyl methacrylate) (PHPMA) gel samples having different initial monomer concentration were treated according to the scaling theory to explain the rubbery behavior of the resulting Hgs. The obtained scaling relation between the reduced modulus and the swelling degree indicated limiting chain extensibility which is neglected in the Flory–Rehner theory. The effective crosslink density and polymer–solvent interaction parameter of PHPMA Hgs were used to interpret the observed deviation. Results showed that the properties of PHPMA Hgs and Cgs can be controlled by varying the HPMA and TEGDMA content. Increase of total monomer concentrations causes a pronounced decrease in the equilibrium swelling degree, and an increase in the elastic response of PHPMA Hgs and Cgs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45889.

Hybrid double‐network hydrogel based on poly(aspartic acid) and poly(acryl amide) with improved mechanical properties

ABSTRACTHydrogels usually have a smaller mechanical strength and toughness than generic polymeric materials. Therefore, many studies report improvements for mechanical properties of hydrogels by preparing double‐network hydrogels, nanocomposite hydrogels, and nanostructured hydrogels. In this study, interpenetrating‐type dually‐crosslinked hydrogels were prepared via free radical crosslinking polymerization of acrylamide monomers in the presence of poly(aspartic acid) and subsequent immersion in a metal ion containing aqueous solution to induce extra physical crosslinking through ionic or coordination bonding. Using this approach, the mechanical properties of inherently weak and brittle homopolymer gels could be improved via interpenetrating the double network formed by both covalent bonding and metal coordination‐assisted reversible physical crosslinks. The preparation, swelling behavior, morphology, and mechanical properties of these hydrogels are presented. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45925.

Swelling behaviors of poly(dodecyl methacrylate-co-methyl eugenol) and poly(dodecyl methacrylate-co-methyl chavicol) gels in essential oil components

Poly(dodecylmethacrylate-co-methyleugenol) P(DDMA-co-Meu) and poly(dodecylmethacrylate-co-methylchavicol) P(DDMA-co-Mch) gels were synthesized in ethanol using free radical cross-linking polymerization method at 60 °C for 24 h in the presence of azobisisobutyronitrile (AIBN) and triethylene glycol dimethacrylate (TEGDMA) as initiator and cross-linker, respectively. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the gels. These gels were used to investigate swelling behaviors in linalool and methyl eugenol, in essential oil mixture of phenyl propanoid and terpenoid, and also in various solvents. While the equilibrium swelling values (ESV) of both gels were higher in linalool than in methyl eugenol, the result was vice versa in the case of essential oil mixture. ESVs of both gels were also obtained in various solvents with different functional groups and the highest ESV of both gels were obtained in toluene, and the lowest ESV of P(DDMA-co-Meu) and P(DDMA-co-Mch) was in methanol and in ethylene glycol, respectively. While P(DDMA-co-Meu) is sensitive to carbon number change in alcohol, P(DDMA-co-Mch) is less sensitive. In the case of esters, increase of carbon number in functional group causes a more significant change in ESV than an increase of carbon number in aliphatic chain. Experimental results were correlated by the first-order and second-order models. The second-order model was more suitable than the other. While P(DDMA-co-Meu) gel swelled in linalool exhibits a Fickian diffusion character, the diffusion mechanism of the gel in methyl eugenol is a non-Fickian one. In the case of P(DDMA-co-Mch), the result is vice versa.