Epoxy Side Groups Research Articles

Impact of Reactive Amphiphilic Copolymers on Mechanical Properties and Cell Responses of Fibrin‐Based Hydrogels

AbstractMechanical properties of hydrogels can be modified by the variation of structure and concentration of reactive building blocks. One promising biological source for the synthesis of biocompatible hydrogels is fibrinogen. Fibrinogen is a glycoprotein in blood, which can be transformed enzymatically to fibrin playing an important role in wound healing and clot formation. In the present work, it is demonstrated that hybrid hydrogels with their improved mechanical properties, tunable internal structure, and enhanced resistance to degradation can be synthesized by a combination of fibrinogen and reactive amphiphilic copolymers. Water‐soluble amphiphilic copolymers with tunable molecular weight and controlled amounts of reactive epoxy side groups are used as reactive crosslinkers to reinforce fibrin hydrogels. In the present work, copolymers that can influence the mechanical properties of fibrin‐based hydrogels are used. The reactive copolymers increase the storage modulus of the hydrogels from 600 Pa to 30 kPa. The thickness of fibrin fibers is regulated by the copolymer concentration. It could be demonstrated that the fibrin‐based hydrogels are biocompatible and support cell proliferation. Their degradation rate is considerably slower than that of native fibrin gels. In conclusion, fibrin‐based hydrogels with tunable elasticity and fiber thickness useful to direct cell responses like proliferation and differentiation are produced.

Highly sensitive impedimetric immunosensor for determination of interleukin 6 as a cancer biomarker by using conjugated polymer containing epoxy side groups modified disposable ITO electrode

A novel impedimetric immunosensor based on a conjugated polypyrrole polymer containing epoxy active side groups (PPCE) modified indium tin oxide (ITO) electrode was developed for detection of interleukin 6 (IL 6), a prostate cancer biomarker. IL 6 receptor was used as a biorecognition molecule and successfully immobilized by covalent linkage on the modified ITO electrode. Pyrrole monomer containing epoxy active side group was electropolymerized on the disposable ITO electrode for the first time and used as an immobilization matrix for IL 6 receptor. The designed biosensor fabrication stages were analyzed by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. For the quantification of IL 6 biomarker, EIS technique was utilized. In addition, the specific immuno-interaction between IL 6 receptor and IL 6 antigen was followed by single frequency impedance (SFI) technique. The resulting biosensor exhibited a linear calibration curve over the 0.02–16 pg/mL IL 6 concentration range, a limit of detection (LOD) of 6.0 fg/mL and a good selectivity against other interference biomarkers. Additionally, an excellent reproducibility, a long storage stability and an acceptable repeatability were found. The proposed impedimetric immunosensor was applied successfully to quantify for the IL 6 biomarker in human serum and it displayed a remarkable response in the real sample analysis with serum samples. In comparison with the commercial ELISA kit, the immunosensor provided a lower LOD and a lower analysis cost. In conclusion, the proposed impedimetric immunosensor could be clinically useful in the early diagnosis of the prostate cancer by detection of the serum samples after only simple dilution with phosphate buffer.

Properties and mechanism of EVM–GMA terpolymer elastomer cross-linked by epoxy–anhydride reaction

In this paper, ethylene–vinyl acetate–glycidyl methacrylate terpolymer elastomer (EVM–GMA) was vulcanized by methyltetrahydrophthalic anhydride (MTHPA) and cross-linked by dicumyl peroxide (DCP) as a reference. Mechanical properties and hot-air aging properties were investigated. The cross-linking mechanism of EVM–GMA reacting with MTHPA was proposed, and a “model vulcanization reaction’ was designed to prove its rationality. The reaction products were characterized by GPC, FT-IR, GC–MS, 1H-NMR and so on. The results indicated that the cured torque MH − ML and cross-link density of EVM–GMA increased first and then decreased with the increase in amount of MTHPA. An optimum of curing, mechanical properties and aging resistance were found at a molar ratio of anhydride to GMA of 1:2. The MTHPA curing reaction catalyzed by tetrabutylammonium bromide was faster compared to the selected DCP cure system, and the mechanical properties, compression set and hot-air aging performance were superior as well. The “model vulcanization reaction” indicated that one molecule of MTHPA successfully reacted with two molecules of the mono-epoxy compound of glycidyl–versatic ester (E10P) to form a hydroxyl-terminated epoxy–anhydride–epoxy polyester structure. Therefore, one molecule of MTHPA can “bridge” two epoxy side groups (provided by GMA) on the adjacent molecular chain of EVM–GMA to realize rubber cross-linking, which proved that the cross-linking mechanism based on epoxy–anhydride reaction for EVM–GMA elastomer proposed in this paper was reasonable.

An ultrasensitive immunosensor based on tri-armed star poly(glycidyl methacrylate) polymer-coated ITO-PET electrode for detection of neuron-specific enolase in human serum

ABSTRACTIn the present study, an ultrasensitive and simple impedimetric biosensor was fabricated for the determination of neuron-specific enolase (NSE) cancer biomarker. Anti-NSE antibody was covalently immobilised on the indium tin oxide-polyethylene terephthalate (ITO-PET) electrode surface coated with polymer Str(PGMA)3. The star poly(glycidyl methacrylate) polymer Str(PGMA)3 had epoxy side groups and these epoxy groups provided a lot of immobilisation points for antibodies. The process of immunosensor fabrication and successful immobilisation of the antibodies and antigens on the ITO-PET electrode was followed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. In addition, EIS technique was utilised for the NSE antigen quantification under optimal experimental conditions. NSE concentration was determined in the range from 0.03 pg/mL to 6 pg/mL with an ultralow detection limit of 9.1 fg/mL. Moreover, the surface topology of the modified surfaces was characterised by scanning electron microscopy (SEM) and atomic force microscopy (AFM) imaging. A low detection limit, a good reproducibility, an excellent storage stability and a good selectivity were obtained. This designed biosensor was employed for the determination of NSE antigen level in human serum samples. The obtained results illustrated that this modification procedure could be applied to determine other biomarkers in human serum samples.

A disposable immunosensor using ITO based electrode modified by a star-shaped polymer for analysis of tumor suppressor protein p53 in human serum

Label-free immunosensor based on tetra armed star-shaped poly(glycidylmethacrylate) (StarPGMA) modified disposable ITO electrode was developed for detection of p53 protein, an important colorectal cancer biomarker. This disposable biosensor was fabricated by spin-coating technique using star-shaped StarPGMA with epoxy side groups. After formation of a stable film with epoxy ends, anti-p53 antibodies were bound to these groups covalently. Stepwise modification of the electrode was followed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) studies. The electrochemical performance of the immunosensor was studied by EIS. Furthermore, the antibody and antigen coupling was monitored by single frequency impedance (SFI) technique. The immunosensor showed a low limit of detection (7 fg/mL) and a linear detection range between 0.02 pg/mL and 4 pg/mL. Additionally, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were utilized for monitoring of immunosensor surface at different stages of fabrication. The antibody coupling on the electrode surface was proved by Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy. Furthermore, the proposed immunosensor had good reproducibility and repeatability.

Elastic polyesters improved by ATRP as reactive epoxy-modifiers of PLA

Block copolymers comprising poly(1,4-butylene adipate) or poly(1,4-butylene adipate-co-terephthalate) middle elastic segment and poly(glycidyl methacrylate-co-n-butyl methacrylate) side chains were obtained using the ARGET ATRP method. These copolymers were characterized by various average molar masses, compositions, numbers of epoxy groups per chain and epoxy equivalent weights and were utilized as reactive modifiers of polylactide (PLA) in extrusion type melt processing at 175 or 190 °C. Contrary to neat PLA processing, when modifiers of lower molar masses were applied then an increase in relative melt viscosity was observed in systems throughout the test run due to reactions of PLA-COOH with epoxy side groups in modifiers. The high molar mass modifiers were not as effective in compensation of the PLA degradation effect. Tensile strength properties of all the obtained compositions extruded in the form of thin strands were measured. Most of the obtained modifiers were able to enhance PLA in elasticity or/and strength. An aliphatic modifier acted as a reactive-internal plasticizer, therefore just slightly worsened the tensile strength but improved the elastic modulus and boosted elongation at break (it was up to 120 times higher than that of PLA). Although aliphatic-aromatic modifiers did not change elongation at break significantly, one of them reinforced and elasticized the PLA based system at once.

Synthesis, film morphology, and performance on cotton substrates of dodecyl/piperazine functional polysiloxane

ABSTRACTA novel polysiloxane bearing dodecyl and epoxy side groups (DESO) was synthesized as an intermediate through hydrosilylation of polymethylhydrosiloxane with allyl glycidyl ether and 1‐dodecene. Then, dodecyl/piperazine functional polysiloxane (DPSO) was prepared through the reaction of N‐aminoethylpiperazine with DESO. The chemical structure of DPSO was characterized with FTIR and 1H‐NMR spectroscopy and its application performance on cotton fabrics was studied. DPSO with dodecyl side groups gifted the treated fabrics with good wettability and whiteness compared with piperazine functional polysiloxane, while with a slightly reduced softness as well as thickening handle. Film morphology, orientation, and performance on cotton substrates of DPSO were investigated by scanning electron microscope, atomic force microscopy, X‐ray photoelectron microscope, and so on. Affected by the dodecyl side groups, DPSO formed relatively hydrophilic, macroscopically smooth but actually uneven films with many dodecyl side chain pillars on the treated substrate surfaces. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40186.

Effect of acrylic copolymer dispersants bearing epoxy groups on rheological and dielectric properties of carbon black‐filled epoxy system

AbstractIn this article, the use of copolymeric dispersants with an acrylic backbone and epoxy side groups for formulating carbon black (CB)‐epoxy composites are described. Six epoxy‐containing acrylic copolymer dispersants were prepared from hexyl methacrylate (HMA), poly(ethylene glycol) ethyl ether methacrylate (PEGMA), and glycidyl methacrylate via a group transfer polymerization technique. The epoxy‐containing acrylic copolymer of the highest concentration of PEGMA showed a desirable passivation effect on CB, and was found to lower the viscosity of the CB‐epoxy paste, leading to the well‐cured composite after heat treatment. The thick composite film prepared by employing the [CB/acrylic dispersant/epoxy] paste was built up on a Cu plate by a screen printing process followed by thermal curing. The dielectric properties of the 3.1 vol % CB‐filled epoxy film showed us high dielectric constant (Dk 4900) and rather low dissipation factor (Df 29%) at 1 MHz. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Silicon-Organic Polyepoxides with Epoxy Side Groups Modified with Chelates

New silicon-organic polyepoxides containing epoxy side groups attached to their main chains have been synthesised by hydride addition (hydrosilylation) of dihydrosiloxanes with the diallyl ether of an epoxidised glycerol group situated at the tertiary carbon atom. General features of the reaction were studied and its kinetic rate constants and reaction order determined. The relative reactivities of various dihydridesiloxanes in the hydrosilylation reaction were determined. The modification of the polyepoxides introduced chelates containing Cu, Ni, Mn and Co atoms into the main chain. The composition and structure of the synthesised polymers were established from elemental, IR and NMR spectral analyses and from DSC, DTA and TGA data. It was established that the glass transition temperature (Tg) and thermo-oxidative stability of the chelate-containing polymers considerably exceeded those of the unmodified polyepoxides.

Precise Synthesis of Poly(silphenylenesiloxane)s with Epoxy Side Functional Groups by Tris(pentafluorophenyl)borane as a Catalyst

1,ω-Dimethylhydroxysilyl, -dimethylhydrosilyl, -dimethylmethoxysilyl -terminated tetramethylsilphenylenesiloxane prepolymers were prepared by sequential palladium-catalyzed dehydrocoupling polymerization of 1,4-bis(dimethylsilyl)benzene with water, reduction with lithium aluminium hydride, and palladium-catalyzed methanolysis. 1,4-Bis[(glycidyl- or cyclohexene oxide-functionalized alkyl)methylhydrosilyl]benzene and methyldimethoxysilanes with the same epoxy groups were synthesized by hydrosilylation of 1,4-bis(methyldihydrosilyl)benzene and methyldimethoxysilane with (terminal olefin-functionalized alkyl) substituted epoxides in the presence of platinum catalyst. 1,4-Bis[(glycidyl- or cyclohexene oxide-functionalized alkyl)methyl(hydroxy or methoxy)silyl]benzenes were obtained by hydrolysis and methanolysis of the hydrosilyl derivatives. Poly(silphenylenesiloxane)s with epoxy side groups were synthesized by hetero-polycondensation of the hydrosilane, hydroxysilane and methoxysilane functional groups in the prepolymer and 1,4-bis[(epoxy-functionalized alkyl)methylsilyl]benzene, or 1,1-dimethoxy(epoxy-functionalized alkyl)methylsilane in the presence of a catalyst. Tris(pentafluorophenyl)borane was found to be an excellent catalyst for the polymerization. Cross-linking a polymer with 1,4-diaminobenzene gave stretchable polymer film by solution cast method.

Zastosowanie pochodnych tris(trimetylosililo)metylowych (trisilowych) w chemii polimerow

Several directions of application of title derivatives, which because of unusual steric hindrance (Scheme A) show excellent thermal, chemical and hydrolytic stability, were presented. Linear liquid crystalline polymers containing trisyl fragments (Scheme B, Table 1) have been discussed as well as the polymers showing dendrimeric structures (Schemes C-E) and modified (cured) polysiloxanes (Fig. 1, Table 2). The syntheses of acid amplifiers (Schemes H-J) used e.g. for curing of polysiloxanes with epoxy side groups were discussed.

Determination of the composition of styrene–glycidyl methacrylate copolymers by FTIR and titration

This paper details a simple method using Fourier transform infrared spectroscopy (FTIR) for determination of the composition of styrene–glycidyl methacrylate copolymers. An FTIR calibration curve based on prepared mixtures of styrene and glycidyl methacrylate monomers at known compositions was obtained. Composition determination of synthesized styrene–glycidyl methacrylate copolymers was performed based on the FTIR calibration curve. The FTIR results were validated and are in good agreement with determination of epoxy side groups in the glycidyl methacrylate monomer by a modified titration method.

Chemical modification of glycidyl methacrylate polymers with 4-hydroxy-4′-methoxybiphenyl groups

Glycidyl methacrylate (GMA), poly(GMA) and a GMA–methyl methacrylate (50–50 mol.%) random copolymer have been modified with 4-hydroxy-4’methoxy biphenyl (4H4MB) moieties through the ring opening reaction of the epoxy group with the aim of demonstrating that the occurrence of limitation of the reaction is due to a steric effect. Chemical modification was determined by 1H NMR and infrared spectroscopy. In the case of the poly(GMA) modification, limitation in conversion has been observed and it was attributed to the steric hindering effect of the previously grafted moieties, which becomes critical at high conversions. In the modification of the GMA–MMA copolymer, all the epoxy side groups have been modified. In this case the epoxy groups are separated on average by one MMA monomer, which is less voluminous than the GMA and non-reactive, hence the approach of 4H4MB groups is much less perturbed. The fully modified polymer was obtained by polymerization of the modified monomer.

Synthesis, Modification, and Characterization of l-Lactide/2,2-[2-Pentene-1,5-diyl]trimethylene Carbonate Copolymers

This paper explores the copolymerization of l-lactide (l-LA) with 2,2-[2-pentene-1,5-diyl]trimethylene carbonate (cHTC). Since cHTC has a cyclohexene group, this provided a route for preparing poly(lactic acid), (PLA), based chains decorated with controlled quantities of CC substituents. Ring-opening copolymerizations of l-LA with cHTC were successfully conducted in bulk by using AlR3−H2O (R = ethyl, isobutyl), Al(OiPr)3, ZnEt2−H2O and Sn(Oct)2 as catalysts. Comparison of these copolymerizations showed that the Sn(Oct)2 catalyst system gave copolymers of relatively higher molecular weight. Increasing the reaction time of Sn(Oct)2 catalyzed copolymerizations from 6 to 24 h resulted in higher copolymer cHTC content and yield but lower copolymer molecular weight. Variation of the comonomer feed ratio was useful in regulating the content of cyclohexene pendant groups in the copolymer. However, regardless of the catalyst used, the mole percent of cHTC incorporated into the copolymer was lower than that used in the monomer feed. Determination of the comonomer reactivity ratios for Sn(Oct)2 catalyzed copolymerizations gave values of 8.8 and 0.52 for l-LA and cHTC, respectively. All gel permeation chromatography (GPC) traces showed unimodal molecular weight distributions. Determination by 13C-NMR of the copolymer sequence fractions HLL, LLL, LLH, HLH, HL, and LH (H = cHTC units, L = l-lactyl units) showed that they were close to those calculated by assuming a Bernoulli statistical propagation. On the basis of these results and the effects of reaction conditions on the copolymer sequence distribution, a mechanism which involves insertion of cHTC into the polymer chain was proposed. Studies by differential scanning calorimetry (DSC) showed that cHTC units in the copolymers disrupted ordering of the l-PLA crystalline phase. Furthermore, the glass transition temperatures (Tg) ranged from 60 (l-PLA) to 33 °C (P(cHTC)). Conversion of CC to epoxy side groups was successfully carried out by using 3-(chloroperoxy)benzoic acid at room temperature with only small decreases in copolymer molecular weight.

Synthesis and characterization of poly(butadiene- b-sulphone) by block-copolycondensation—II. Synthesis from α,ω-dicarboxylic oligobutadienes and α,ω-diepoxy oligosulphones

The synthesis of poly(butadiene- b-sulphone) by two methods was described in part I ( Eur. Polym. J. 20, 305 [1]). The results obtained by reaction of α,ω-dicarboxylic oligobutadiene with α,ω-diepoxy oligosulphones are reported here. The kinetics of the reaction are studied on models: reaction orders, rate constants, activation parameters are determined. Their values fit Madec's kinetic pattern [2] and are close to those obtained by Crépeau [6] for the grafting of hydroxybenzoic acid onto a copolymer bearing epoxy side-groups. Contribution of the side-reaction [2] is quantified. Block-copolycondensation of the reactive oligomers are carried out both in solution and in the melt. Contribution of the side-reaction is higher in the melt than in solution, but in both cases block-copolymers are obtained and characterized by GPC.

Studies of methyl methacrylate–glycidyl methacrylate copolymers: Copolymerization to low molecular weights and modification by ring‐opening reaction of epoxy side groups

AbstractThe copolymerization of methyl methacrylate (MMA) with glycidyl methacrylate (GMA) at 60°C with 2,2′‐azobisisobutyronitrile (AIBN) as radical initiator and in the presence of thiophenol (TP) as chain‐transfer agent has been investigated. Monomer reactivity ratios for MMA and GMA are found to be r1 (MMA) = 0.80 ± 0.015 and r2 (GMA) = 0.70 ± 0.015, from which Q and e values are calculated to be 0.68 and −0.36 for GMA. The initial rate of copolymerization Rp at 60°C with AIBN (0.02 mole/l.) and TP (0.1, 0.01 mole/l.) were found to increase nonlinearly with increasing GMA concentration in the monomer feed. Homopolymerizations of MMA and GMA monomers were studied in the presence and in the absence of thiophenol. The values of δ (= kt1/2/kp) for MMA and GMA were determined to be 10.25 and 3.00 (mole‐sec/l.)1/2, respectively. Using the values r1 (MMA), r2 (GMA), δ1 (MMA), δ2 (GMA), and Rp, the cross‐termination constants ϕ for MMA–GMA monomers were determined (average value ϕ = 0.42). The increase in Rp values with increasing GMA content has been attributed to the cross‐termination of MMA–GMA radicals. The transfer constant of TP has also been determined for GMA and found to be 1.00. A MMA–GMA copolymer of low molecular weight, containing 2.01% of oxirane oxygen, was modified by opening of the oxirane ring of GMA by reaction with diethanolamine (DEA). The reaction was carried out at 70 ± 1°C, the copolymer content of epoxy groups and the amine being assumed to be in the molar ratio of 1:4. Addition of a hydrogen‐bond acceptor like nitrobenzene decreases, while addition of a hydrogen‐bond donor like phenol increases the rate of epoxy ring opening with DEA. This indicates that a hydrogen‐bonded intermediate is involved in this reaction and that it weakens the epoxy ring and enhances the rate of its opening with DEA. From the studies of the conversion rates, existence of a “nonspecific” side reaction has been shown which involves the reaction of the terminal epoxy groups of the copolymer and the hydroxyl groups of DEA or formed in the reaction with DEA (involves a chain coupling). DEA can be trifunctional in this reaction. This has been further confirmed from the increase of number‐average molecular weights M̄n of the copolymers resulting from this coupling and the nitrogen content in the copolymers after modification with DEA.

Determination of epoxy side groups in polymers. Infrared analysis of methyl methacrylate-glycidyl methacrylate copolymers

Determination of epoxy side groups in polymers. Infrared analysis of methyl methacrylate-glycidyl methacrylate copolymers