Methacrylate Groups Research Articles

A water-soluble cyclometalated iridium(III) complex with fluorescent sensing capability for hypochlorite

Herein, a novel cyclometalated iridium (III) complex (Ir-1) with good water-solubility was designed and synthesized to sensitively detect hypochlorite (ClO−) in aqueous buffer solution. The sensor Ir-1 was prepared by incorporating a methacrylate group into cyclometalated ligands, which was a specific response site toward ClO− through an oxidation process. Ir-1 displayed strong emission at 615 nm, while significant fluorescence quenching was observed upon addition of ClO− with a low detection limit of 0.41 μM. Moreover, probe Ir-1 exhibited a rapid response (<30 s) for ClO− with high selectivity over potentially competing species. The sensing process was evidenced by NMR and MS characterization. Further application in bioimaging of ClO− was successfully performed in living HepG2 cells.

Expanding the chemistry of single‐ion conducting poly(ionic liquid)s with polyhedral boron anions

AbstractThe synthesis of a new family of single‐ion conducting random copolymers bearing polyhedral boron anions is reported. For this purpose two novel ionic monomers, namely [B12H11(OCH2CH2)2OC(O)C(CH3)CH2]2−[(C4H9)4N+]2 and [8‐(OCH2CH2)2OC(O)C(CH3)CH2‐3,3′‐Co(1,2‐C2B9H10)(1′,2′‐C2B9H11)]−K+, having methacrylate function, diethylene glycol bridge and closo‐dodecaborate or cobalt bis(1,2‐dicarbollide) anions were designed. Such monomers differ from previously reported ones by (i) chemically attached highly delocalized boron anions, by (ii) valency of the anion (divalent anion and monovalent one) and by (iii) the presence of oxyethylene flexible spacer between the methacrylate group and bonded anion. Their free radical copolymerization with poly(ethylene glycol) methyl ether methacrylate and subsequent ion exchange provided lithium‐ion conducting polyelectrolytes showing low glass transition temperature (−53 to −49 °C), ionic conductivity up to 9.1 × 10−7 S cm−1, lithium transference number up to 0.61 (70 °C) and electrochemical stability up to 4.1 V versus Li+/Li (70 °C). The incorporation of propylene carbonate (20–40 wt%) into the copolymers resulted in the enhancement of their ionic conductivity by one order of magnitude and significantly increased their electrochemical stability up to 4.7 V versus Li+/Li (70 °C). © 2019 Society of Chemical Industry

Ductile and biodegradable poly (lactic acid) matrix film with layered structure

Polylactide (PLA), as a biodegradable packing material, has attracted plenty of attention. However, some problems still limit the application of PLA in packing industry such as the inherent brittleness and low crack propagation resistance. In order to overcome these challenges, we blended PLA with a reactive toughening agent (Ethylene-Acrylic ester-Glycidyl methacrylate terpolymer) during extrusion and film processing. The glycidyl methacrylate groups in toughening agent offered some sites to react with COOH and OH groups of PLA thus leaded to a great interfacial compatibility. The proper compatibility was the premise of adjusting the phase structure of blend and film based on different processing methods. The blend had a sea-island structure after melting extrusion and heat pressed technologies while film formed annular layer structure after film blowing. The structure determined properties. Both the toughness and melt strength of blends had been improved. Moreover, it was interesting to found that tear strength of film with 10% toughening agent dramatically increased to 197.8 KN/m and 137.7 KN/m in the transverse direction (TD) and in the machine direction (MD), respectively. Besides, the elongation at break of film could reach 242.2% in MD. This work exhibited that phase morphology was significant for mechanical performances.

Development and characterization of a photocurable alginate bioink for three-dimensional bioprinting.

Alginate is a biocompatible material suitable for biomedical applications, which can be processed under mild conditions on irradiation. This paper investigates the preparation and the rheological behavior of different pre-polymerized and polymerized alginate methacrylate systems for three-dimensional photopolymerization bioprinting. The effect of the functionalization time on the mechanical, morphological, swelling, and degradation characteristics of cross-linked alginate hydrogel is also discussed. Alginate was chemically-modified with methacrylate groups and different reaction times considered. Photocurable alginate systems were prepared by dissolving functionalized alginate with 0.5- 1.5% w/v photoinitiator solutions and cross-linked by ultraviolet light (8 mW/cm2 for 8 minutes).

Post-modification of Cellulose Nanocrystal Aerogels with Thiol-Ene Click Chemistry.

The functionalization of cellulose nanocrystal (CNC) aerogels was achieved through a two-step synthetic procedure. CNC aerogels were prepared under hydrothermal conditions, followed by solvent exchange and critical point drying. The CNC aerogels were functionalized with a methacrylate group and then underwent thiol-ene click chemistry to impart a range of functionalities onto the surface of the CNC aerogel. The use of the functionalized aerogels as oil absorbents was then investigated, with the most hydrophobic CNC aerogel, 1 H,1 H,2 H,2 H-perfluorodecanethiol-functionalized CNC aerogel, exhibiting the highest absorption of xylenes at 2.9 mL g-1.

OBTAINING SOME THERMOD AINING SOME THERMODYNAMIC PARAMETERS CONTAINING ME AINING METACRYLATE AND ALL TE AND ALLYL GROUPS CON YL GROUPS CONTAINING IN COMPOSITION

The article discusses the preparation of some thermodynamic parameters characterizing the final product of complex radical polymerization of amino alkyl acrylate derivatives containing both methacrylate and alkyl groups of low molecular weight compounds with electron acceptors - polymerization initiators at temperatures that exclude thermal decomposition of the initiators themselves. The equilibrium constant of the complication reaction and the molar extinction coefficient of the complex were determined by graphically solving the Bеneshe-Hildebrand equation, the heats of complex formation, entropy, Gibbs energy were found, and the elemental composition of low molecular weight and high molecular weight substances was determined. As can be seen from the studies, the molar extinction coefficient of the complex practically does not depend on temperature, and the equilibrium constant of the complexation reaction even in a narrow temperature range (283–293 K) increases with increasing temperature. The structure and composition of the synthesized monomeric and polymer salt were also considered in the work, and confirmed by IR-spectroscopy and analysis of elemental composition, the obtained spectroscopic data showed that the unit of the formed polymer corresponds in composition and structure to the monomeric quaternary salt, and the allyl bond in the polymers is preserved. It can be seen from the studies that, with an increase in the concentration of both the monomer and the initiator, the reaction rate naturally increases.

A Vinylic Rotaxane Cross‐Linker Containing Crown Ether for Hydrophilic and Hard Rotaxane‐Networked Polymers

Rotaxane‐cross‐linked polymers (RCP), which have rotaxane structures at the cross‐link points, show unique physical properties originating from the movable cross‐link points. Herein, poly(N,N‐dimethylacrylamide) (PDMAAm) and poly(N‐isopropylacrylamide) (PNIPAm) which are well known as hydrophilic polymers and whose glass transition temperatures are much higher than room temperature, were applied as matrix polymers for RCPs. These RCPs are easily and successfully synthesized by radical polymerization of vinyl monomers in the presence of small amounts of [2]rotaxane cross‐linker (RC) comprising one wheel and one axle component with a methacrylate group on each component. As the result, PDMAAm‐based RCP without any solvents and PNIPAm‐based RCP swelled with water were much tougher than corresponding covalently cross‐linked polymers. It is confirmed that RC endows both of the hard polymer networks and soft hydrogels with toughness.

Preparation of polymerizable thermal initiator and its application in photo-induced thermal frontal polymerization

Photo-induced frontal polymerization has been growing interesting in the recent decades. However, the conflict among the frontal starting temperature, the storage stability and the high leachability remain problems to be solved. A new polymerizable methacrylate functionalized aliphatic peroxide thermal initiator (named as IEM-HDHP) through modifying methacrylate group into the 2,5-dihydroperoxy-2,5-dimethylhexane (HDHP) was successfully prepared. In the photo-induced frontal polymerization investigated, IEM-HDHP showed medium photo-induced frontal polymerization starting temperature, frontal velocity and best storage stability compared with two commercial thermal initiators (benzoyl peroxide (BPO) and 1-(2-hydroperoxypropan-2-yl) benzene) (CHP). What’s more, the lowest amount of small molecular leachability makes it outstanding from the two competitors. At the same time, IEM-HDHP is the only one to lead to the sample stick with complete and smooth appearance in this work.

Polyhedral oligomeric silsesquioxane grafted silica-based core-shell microspheres for reversed-phase high-performance liquid chromatography.

Polyhedral oligomeric silsesquioxane (POSS) was used to modify spherical silica to fabricate core-shell POSS@SiO2 microspheres. The material was characterized by Fourier transform infrared experiments, scanning electron microscopy, thermogravimetric analysis and elemental analysis. The material was also used as astationary phase for HPLC separation. The POSS@SiO2 column exhibits areverse-phase liquid chromatography (RPLC) retention mechanism. The column efficiency of alkylbenzenes reaches 67,200 plates·m-1. The POSS@SiO2 column was also utilized for separation of basic anilines and polycyclic aromatic hydrocarbons. Compared with the commercial C8 column, the POSS@SiO2 column exhibits enhanced separation selectivity. The column was also used for the separation of synthetic cytokinins 6-benzylaminopurine and 6-furfurylaminopurine in bean sprout after extraction. In addition, the methacrylate groups on the surface of the POSS@SiO2 microsphere were further functionalized so as to facilitate the fabrication of versatile stationary phases with various separation mechanisms. Graphical abstract Schematic presentation of the two-stepfabrication of polyhedral oligomeric silsesquioxane grafted silica-based (POSS@SiO2) core-shell microspheresfor use in HPLC.

Self-Assembled Injectable Nanocomposite Hydrogels Coordinated by in Situ Generated CaP Nanoparticles for Bone Regeneration.

Due to the great similarity to the natural extracellular matrix and minimally invasive surgeries, injectable hydrogels are appealing biomaterials in cartilage and bone tissue engineering. Nevertheless, undesirable mechanical properties and bioactivity greatly hamper their availability in clinic applications. Here, we developed an injectable nanocomposite hydrogel by in situ growth of CaP nanoparticles (ICPNs) during the free-radical polymerization of dimethylaminoethyl methacrylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) matrix (PDH) for bone regeneration. The ICPNs are self-assembled by incorporation of poly-l-glutamic acid (PGA) with abundant carboxyl functional groups during the formation of carboxyl-Ca2+ coordination and further CaP precipitation. Furthermore, the carboxyl groups of PGA could interact with the tertiary amines of DMAEMA fragments and thus improve the mechanical strength of hydrogels. Upon mixing solutions of DMAEMA and HEMA bearing PGA, Ca2+, and PO43-, this effective and dynamic coordination led to the rapid self-assembly of CaP NPs and PDH nanocomposite hydrogels (PDH/mICPN). The obtained optimal nanocomposite hydrogels exhibited suitable injectable time, an enhanced tensile strength of 321.1 kPa, and a fracture energy of 29.0 kJ/m2 and dramatically facilitated cell adhesion and upregulated osteodifferentiation compared to hydrogels prepared by blending ex situ prefabricated CaP NPs. In vivo experiments confirmed the promoted osteogenesis, which shows a striking contrast to pure PDH hydrogels. Additionally, the methacrylate groups on the monomers could easily be functionalized with aptamers and thereby facilitate recognition and capturing of bone marrow stromal cells both in vitro and in vivo and strengthen the bone regeneration. We believe that our conducted research about in situ self-assembled CaP nanoparticle-coordinated hydrogels will open a new avenue for bone regeneration in the future endeavors.

Effect of benzalkonium chloride on dentin bond strength and endogenous enzymatic activity

Objective: This in vitro study evaluated at baseline (T0) and over time (T12 months), the effect of a multi-mode universal adhesive compared with two experimental formulations blended with different concentrations of benzalkonium chloride (BAC), on bond strength and endogenous enzymatic activity.Methods and materials: Specimens were assigned to the following groups according to the adhesive protocol: G1) All-Bond Universal (ABU) self-etch (SE); G2) ABU + 0.5% BAC SE; G3) ABU + 1% methacrylate BAC SE; G4) ABU etch-and-rinse (E&R); G5) ABU + 0.5% BAC E&R; G6) ABU + 1% methacrylate BAC E&R. Gelatin zymography was performed on dentin powder obtained from eight human third molars. Endogenous enzymatic activity within the hybrid layer was examined using in situ zymography after 24 h (T0) or 1-year storage in artificial saliva (T12). Forty intact molars were prepared for microtensile bond strength test at T0 and T12. Results were statistically analyzed with three-way ANOVA (α = 0.05).Results: Gelatin zymography assay and in situ zymography quantification analyses indicated that all the BAC-containing formulations decreased matrix metalloproteinase expression. However, in situ zymography showed a general trend of enzymatic activity increase after aging. Microtensile bond-strength testing showed decrease in bond strength over time in all the tested groups; performances of the 1% methacrylate BAC experimental groups were worse than the control.Conclusions: BAC-containing adhesives reduce endogenous enzymatic activity both immediately and over time. However, independently from the adhesive employed, increase in the gelatinolytic activity over time and decrease in bond strength was found (especially in the BAC + 1% methacrylate groups), probably due to impaired polymerization properties.Clinical significance: Adhesives containing protease inhibitors are practical and efficient tools in clinical practice for enhancement of the longevity of dental restorations. However, extensive investigation of the mechanical and adhesive properties of the material is necessary prior to their clinical use.

Phase equilibria and cloud-point behavior for the poly(2-phenylethyl methacrylate) in supercritical CO2 with monomers as co-solvent

This work focuses on the non-ideal phase equilibrium of methacrylate and acetate groups with weak polar. Phase behavior measurements were performed using a synthetic method by observing the bubble-point and cloud-point in a variable volume high-pressure view cell. The cloud-point and vapor-liquid experimental data at various temperatures and several pressures are obtained for two-component and three-component mixtures of supercritical CO2 + P(2-PEMA) [poly(2-phenylethyl methacrylate)] + co-solvents [2-phenylethyl methacrylate (2-PEMA), phenyl acetate (PAe), and 2-phenylethyl acetate (2-PEAe)] and CO2 + monomers (2-PEMA, PAe, and 2-PEAe) systems. The product data for the P(2-PEMA) + co-solvents mixture under supercritical CO2 are measured at up to 474.8 K and up to 200.86 MPa. The product sources for the CO2 + P(2-PEMA) + x wt.% 2-PEMA solutions were reported in changes of the p–T (pressure vs temperature) diagram, and with 2-PEMA weight fractions of (29.7, 35.1, 39.1, 44.5, and 52.2) wt.%. To obtain a two (vapor + liquid) region and three (liquid1 + liquid2 + vapor) region, the CO2 + P(2-PEMA) + 56.0 wt.% 2-PEMA, CO2 + P(2-PEMA) + 58.2 wt.% PAe, and CO2 + P(2-PEMA) + 57.6 wt.% 2-PEAe phase segregation curve bisects a supercritical liquid region → (liquid + vapor) region at ∼410 K and ∼23 MPa (2-PEMA), ∼365 K and ∼14 MPa (PAe), and ∼385 K and 18 MPa (2-PEAe), respectively.The equilibria data for the 2-PEMA, PAe, and 2-PEAe in CO2 are a significant in determining their suitability as organic solvent in various chemical processes. The equilibrium curves of the two-component solution for 2-PEMA, PAe, and 2-PEAe in compressed CO2 are examined using a synthetic method at (313.2 ≤ T ≤ 393.2) K and pressure of p ≤ 26.66 MPa. The three CO2 + 2-PEMA, CO2 + PAe, and CO2 + 2-PEAe two-component systems have mixture-critical loci that show the highest in the (p–T) space between the Tc of CO2 and 2-PEMA, PAe, or 2-PEAe. The CO2 + 2-PEMA, CO2 + PAe and CO2 + 2-PEAe mixtures display type-I curves. The product data for the CO2 + 2-PEMA, CO2 + PAe, and CO2 + 2-PEAe binary mixtures are correlated with the Peng–Robinson equation of state by a mixing rule with adjustable parameters of kij, and ηij.

Comparison of Various Implant Provisional Resin Materials for Cytotoxicity and Attachment to Human Gingival Fibroblasts

The aim of this study was to evaluate the responses of human gingival fibroblast (HGF-1) in contact with provisional materials with various chemical compositions and fabricated using different methods. A total of 210 specimens in eight experimental groups were used. Groups were divided by chemical compositions (poly[ethyl methacrylate], poly[methyl methacrylate], bis-acryl, and hybrid ceramic) and fabricating methods (direct, indirect, and computer-aided design/computer-aided manufacturing [CAD/CAM]). To evaluate the surface characteristics of each group, roughness, water contact angle, and degree of conversion were measured. The responses of HGF-1 to provisional materials were evaluated with cytotoxicity and cell attachment assay. The roughness, surface energy, degree of conversion, level of cytotoxicity, and cell attachment were compared between groups using one-way analysis of variance (ANOVA) and Tukey's multiple comparison (α = .05). The poly(ethyl methacrylate)-direct/indirect and poly(methyl methacrylate)-direct/indirect groups showed higher roughness than the bis-acryl-direct/indirect, poly(methyl methacrylate)-CAD/CAM, and hybrid ceramic-CAD/CAM groups with statistical significance (P < .05). The poly(ethyl methacrylate)-direct group showed the significantly highest water contact angle, and the hybrid ceramic-CAD/CAM group showed the lowest water contact angle (P < .05). The groups that used indirect fabrication methods showed a higher degree of conversion than those that used direct fabrication methods, regardless of chemical composition (P < .05). The poly(ethyl methacrylate) groups showed significantly lower cell viability than the other groups regardless of fabricating methods (P < .05). The poly(ethyl methacrylate)-direct method group showed the lowest cell attachment, and the hybrid ceramic-CAD/CAM method group showed the highest cell attachment (P < .05). Poly(methyl methacrylate) and bis-acryl have lower cytotoxicity to HGF-1 than poly(ethyl methacrylate). Indirect fabrication and CAD/CAM are recommended to prevent residual monomer and achieve high cell attachment. To use direct fabrication methods, the auto-mix system is beneficial for the favorable cell response, as it derives a smooth surface.

UV-cross-linked poly(ethylene oxide carbonate) as free standing solid polymer electrolyte for lithium batteries

Aliphatic polycarbonates have emerged as promising polymer electrolytes due to their combination of moderate ionic conductivity and high lithium transference numbers. However, the mechanical properties of the aliphatic polycarbonates polymer electrolytes are usually weak due to the low molecular weight achieved and plasticization effect of the added lithium salt. In this article, we present a copolymer having poly(ethylene oxide) segments linked by carbonate groups with cross-linkable methacrylic pendant groups. Once the polymer and the lithium salt were mixed, the poly(ethylene oxide carbonate) was cross-linked by UV light producing a free standing solid polymer electrolyte (SPE). Different SPE formulations were designed by varying the LiTFSI concentration within the polymer matrix showing the highest ionic conductivity of 1.3·10−3 S cm−1 and a lithium transference number of 0.59 at 70 °C. 7Li solid-state NMR experiments were used to correlate the lithium cation environment and dynamics with ionic conductivity. At the same temperature the electrochemical stability window was analyzed, and a reasonable value of 4.9 V was achieved. The study was complemented by mechanical and thermal stability measurements. Finally, the optimized UV-cross-linked poly(ethylene oxide carbonate) was tested as electrolyte in lithium metal symmetric cell at 70 °C, showing low over-potential values and a stable solid electrolyte interphase layer.

A Near-Infrared Ratiometric Fluorescent Probe for Highly Selective Recognition and Bioimaging of Cysteine.

A benzothiazole-based near-infrared (NIR) ratiometric fluorescent probe (HBT-Cys) was developed for discriminating cysteine (Cys) from homocysteine (Hcy) and glutathione (GSH). The probe was designed by masking phenol group in the conjugated benzothiazole derivative with methacrylate group that could be selectively removed by Cys, and therefore an intramolecular charge transfer (ICT) fluorescence was switched on in the NIR region. In the absence of Cys, the probe exhibited a strong blue fluorescence emission at 431 nm, whereas a NIR fluorescence emission at 710 nm was significantly enhanced accompanied by a decrease of emission at 431 nm in the presence of Cys, allowing a ratiometric fluorescence detection of Cys. The fluorescence intensity ratio (I710nm/I431nm) showed a good linear relationship with Cys concentration of 1–40 μM with the detection limit of 0.5 μM. The sensing mechanism was explored based on MS experimental analysis and DFT theoretical calculation. Moreover, the fluorescent probe was successfully used for fluorescence bioimaging of Cys in living cells.

High modulus, enzyme-degradable poly(trimethylene carbonate)-peptide biohybrid networks formed from triblock prepolymers.

Biohybrid networks have the potential to have stiffnesses equivalent to that of native soft connective tissues as well as cell-mediated degradation behavior. Most strategies to generate such materials to date have utilized crosslinking of two separate and orthogonally functionalized polymers. Herein we describe a triblock prepolymer consisting of a central enzyme degradable peptide block flanked by two synthetic, hydrolysis resistant poly(trimethylene carbonate) blocks (PTMC) or poly(ethylene glycol)-PTMC blocks terminated in methacrylate groups. To form these prepolymers heterobifunctional PTMC and PEG-PTMC were prepared, possessing a vinyl sulfone terminus and a methacrylate terminus. These polymers were conjugated to a di-cysteine containing peptide through a Michael-type addition to form cross-linkable prepolymers. These prepolymers were then photo-cured to form enzyme degradable networks. The compressive moduli of the resulting water swollen networks was within the range of many soft connective tissues and was inversely proportional to the water solubility of the prepolymers. The prepolymer water solubility in turn could be tuned by adjusting PTMC molecular weight or by the addition of a PEG block. In vitro degradation only occurred in the presence of matrix metalloproteinases, and was fastest for networks prepared with prepolymers of higher water solubility.

Study of fourier transform infrared of adding metallic nanofillers on heat cure acrylic resin treated by microwave

Background: Polymethylmethacrylate (PMMA) has been the most popular material for the construction of denture bases since 1937. This is largely due to its favourable although not ideal characteristics. Aims of the study: To study the structural characterisation using Fourier transform infrared (FTIR) of adding aluminium oxide (Al2O3) and silver nanofillers on heat cure acrylic powder treated with microwave radiation and microwave-treated PMMA powder ground by micronizer. Materials and Methods: PMMA powder was treated with microwave radiation at a power level of 360 watt for ¾ h. The obtained PMMA powder was then grinded using a domestic blender group (V). The next step is particle size reduction of the microwave-treated PMMA powder using micronizer group (M). Two concentrations of Al2O3and Ag nanoparticles (NPs) were added separately into untreated PMMA powder group (P) and microwave-treated PMMA powder group (V and M) compared with the control group. The structural characterisations of all experimental groups are determined by FTIR. The samples were divided into 15 groups, one sample for each group. Results: The FTIR analysis has confirmed that the structural behaviour of both microwave and micronizer groups showed that there were no changes in the regions of the band locations for C=C and C=O when compared with the control one. The infrared spectra of all acrylic groups with (Al2O3and Ag) NPs additives showed all of the unique peaks attributed to the PMMA. These bands appeared in the same regions of the acrylic except the carbon double bond carbon (C=C) were absent in the infrared spectrometer chart. Conclusion: The FTIR test charts provide strong evidence that there are no chemical changes in all experimental groups. Except for the C=C band from the methacrylate group did not appear in samples containing NPs, which in turn indicates that the residual monomer of these groups is remarkably decreased.

Antibacterial and thermomechanical properties of experimental dental resins containing quaternary ammonium monomers with two or four methacrylate groups

Resins with strong antibacterial and thermomechanical properties are critical for application in oral cavities. In this study, we first evaluated the antibacterial effect of an unfilled resin incorporating 1, 4, and 7 mass% of quaternary ammonium salt (QAS) monomers containing two methacrylate groups (MAE-DB) and four methacrylate groups (TMH-DB) against Streptococcus mutans, and tested the cytotoxicity and thermomechanical properties of the 4 mass% MAE-DB and TMH-DB modified resin materials. A neat resin without a QAS monomer served as the control. As the concentration of both QAS monomers increases, the formation of a Streptococcus mutans biofilm on the experimental material is increasingly inhibited. The results of colony forming unit counts and the metabolic activity showed that both the MAE-DB and TMH-DB modified resins have a strong bactericidal effect on the bacteria in a biofilm, but no bactericidal effect on the bacteria in a solution. The viability-staining and morphology results also demonstrate that the bacteria deform, lyse, shrink, and die on the surface of the two QAS-modified resins. Cytotoxicity results show that the addition of TMH-DB can reduce the cytotoxicity of the resin, while the addition of MAE-DB increases the cytotoxicity of the resin. DMA results show that a TMH-DB modified resin has a higher storage modulus than a MAE-DB modified resin owing to its better crosslink density. The two groups of experimental resins showed a similar glass transition temperature. These data indicate that the two QAS monomers can impart similar antibacterial properties upon contact with a dental resin, whereas TMH-DB can endow the resin with a higher crosslink density and storage modulus than MAE-DB because it has more polymerizable groups.

Evaluation and comparison of the effect of different chemical surface treatments (monomethyl methacrylate monomer, dichloromethane, and 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer solvent) on the shear bond strength of acrylic resin teeth to the heat cure denture base resin

Background: Prefabricated acrylic resin teeth for dentures were started in use from 1940. About 26%–33% of denture repairs are the result of debonded teeth which cause distress and increased cost for patients. Taking into consideration the importance of properly bonded teeth to denture bases, this in-vitro study was designed to evaluate and compare the effects of three different chemicals on shear bond strength of cross-linked acrylic resin teeth with heat cure denture base resin. Methodology: This study was carried out in Government Dental College and Hospital, Mumbai, in collaboration with the Indian Institute of Technology, Powai. For the purpose of the study, 100 maxillary right central incisors, made up of heat cure cross-linked acrylic resin (MAARC) were collected. The wax samples were randomly divided according to systematic random sampling and coded into four groups of 25 samples each. The four groups were the control group, the monomethyl methacrylate group, the dichlormethane group and trichloroethane+ monomethyl methacrylate group. Results: The control group had lowest value for shear bond strength ranging from 117 N to 181 N with a mean of 147.8 N, whereas 1:1 mixture of v/v of 30% trichloromethane and monomethyl methacrylate had the highest value ranged from 145 N to 310 N with the mean value of 224.88 N. Among the chemical solvents used, monomethyl methacrylate had the lowest shear bond strength ranging from 120 N to 256 N with the mean value 187.32 N. Conclusion: The study concluded that chemical surface treatment of cross-linked acrylic teeth with 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer gave the highest strength.

In situ photocrosslinkable hyaluronic acid‐based surgical glue with tunable mechanical properties and high adhesive strength

ABSTRACTHyaluronic acid (HA), a naturally occurring linear polysaccharide, has been widely used as a key biomaterial in a range of cosmetic and therapeutic applications. Its excellent biocompatibility and bio‐functions related to tissue regeneration encourage the development of HA‐based hydrogels to expand its applications. This study details an in situ forming surgical glue based on photocrosslinkable HA, providing tunable mechanical properties and firm tissue adhesion under wet and dynamic conditions. Depending on the degree of photocrosslinkable methacrylate groups in HA polymer chains, the mechanical properties of hyaluronate methacrylate (HAMA) hydrogels prepared by UV photocrosslinking was improved. Ex vivo adhesion tests revealed that HAMA hydrogels exhibited 3‐fold higher shear adhesive strength compared to gelatin methacryloyl hydrogels and achieved firm adherence to the porcine skin tissue for several weeks. The high adhesive strength of HAMA hydrogels, under dry and wet conditions, suggests that it may have great promise as a tissue adhesive. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 522–530