Methacrylate Groups Research Articles

A novel multifunctional soft robotic transducer made with poly (ethylene-co-methacrylic acid) ionomer metal nanocomposite

Reported is realization of a novel ionic electro-active biomimetic soft robotic polymer metal nanocomposite known as poly (ethylene-co-methacrylic acid) metal composite (called EMAMC in this paper) capable of functioning as soft robotic biomimetic actuators, energy harvesters and sensors. By soft robotic it is meant that these materials are easily deformable soft plastics like an elephant trunk. Further reported is the manufacturing methodology of the novel multi-functional electroactive polymer metal nanocomposite EMAMC. The electro-less chemical plating is performed by a chemical REDOX operation on poly (ethylene-co-methacrylic acid) or (PEMAA) ionomer with a metal. PEMAA is a commercially available ionomer commercially known as Surlyn® by DuPont and used for manufacturing golf balls. Surlyn® is a copolymer of ethylene and methacrylic acid groups and is partially neutralized with Na+ ions. To increase the ion exchange capability of Surlyn® the polymer is subjected to a chemical hydrolysis in potassium and sodium hydroxides (KOH, NaOH) and dimethyl sulfoxide (DMSO). This procedure is followed by a chemical REDOX procedure in which PEMAA is first oxidized in a metallic salt solution followed and then reduced in a lithium and sodium borohydride solutions to deposit metallic nanoparticles near boundaries and on the surfaces of hydrolyzed Surlyn®. This REDOX operation creates highly conductive electrodes on and near boundary surfaces. It is then observed that application of a low voltage across the EMAMC causes it to deform softly (actuation mode) with a significant force density and soft bending and deforming the EMAMC will generate electricity (energy harvesting and sensing modes). The preliminary results of actuation and sensing of the EMAMC are reported in this paper.

Preliminary Study on Degree of Conversion of UV Curable Maleinated Acrylated Epoxidised Palm Oil Pressure Sensitive Adhesives Synthesised with Isobornyl Methacrylate Monomer via FTIR-ATR Analysis

UV curable PSA of maleinated acrylated epoxidised palm oil (MAEPO) from palm oil via UV LED lamp has been introduced with the existence of Chivacure 300 as photoinitiator. By involving the isobornyl methacrylate (ISBMA) as a monomer in the PSA formulation, the degree of conversion recorded low percentage of conversion, which was below 50 % although the loading of photoinitiator has been raised to 5 parts per hundred (phr). The ISBMA has affected to the slow curing speed on the maleinated PSA and restricted the conversion of C=C to more than 50 % even though the curing time and photoinitiator loading has been increased up to 300 min and 5 phr. It is expected that the double bonds are still present in the synthesised of PSA which indicated that most molecules were bonded at one end of another in methacrylate group. In the present study, real-time FTIR-ATR spectroscopy was used to follow the crosslinking process of the adhesive and the adhesive properties of the cured coatings.

Bond strength of stainless steel orthodontic brackets bonded to prefabricated acrylic teeth.

The purpose of this in-vitro study was to evaluate the force to debond stainless steel orthodontic brackets bonded to acrylic teeth using different combinations of adhesive and surface treatments. One hundred prefabricated upper lateral incisor acrylic teeth were divided into 4 equal groups: Transbond XT® adhesive only (Group 1, control), Transbond XT® adhesive with sandblasting (Group 2), Transbond XT® adhesive with abrasion / + methyl methacrylate (MMA) (Group 3) and Triad® Gel only (Group 4). The force in Newtons (N) to debond the brackets was measured. One-way analysis of variance (ANOVA) and pairwise multi-comparison of means (Šidak's adjustment) were undertaken. The highest force to debond was recorded for Group 2 (275.7 N; SD 89.0) followed by Group 3 (241.9 N; SD 76.0), Group 1 (142.7 N; SD 36.7) and Group 4 (67.9 N; SD 21.1). Significant differences in bond strength measurements between the experimental groups were detected. Mean force values for the groups revealed no significant differences between Group 2 and Group 3 (p>0.05). Both sandblasting and surface abrasion/+ application of methyl methacrylate (MMA) in combination with Transbond XT® adhesive are recommended for bonding stainless orthodontic brackets to acrylic teeth.

A Dual-Bonded Approach for Improving Hydrogel Implant Stability in Cartilage Defects.

Integration and stability of hydrogels and surrounding cartilage/bone tissue is crucial for both immediate functionality and long-term performance of the tissue. In this work, chondroitin sulphate (CS) a polysaccharide found in cartilage and other tissues was used to synthesize a tough hydrogel that was chemically functionalized with methacrylate and aldehyde groups, bonding to surrounding tissue via a dual-bonded approach. The hydrogel can not only chemically anchor onto implanted titanium at the subchondral bone, but also on cartilage tissue via the Schiff-base reaction. In vitro experiments confirmed that the strategy improved hydrogel implant stability with cartilage tissue, was favorable for chondrocyte attachment, and has the potential to quickly and effectively repair cartilage defects and maintain joint functionality for a long time.

A bioactive hyaluronic acid–based hydrogel cross-linked by Diels–Alder reaction for promoting neurite outgrowth of PC12 cells

In order to improve neurite outgrowth on the in situ formed hyaluronic acid–based hydrogel, furan and methacrylate groups were grafted on hyaluronic acid successively. Furthermore, a laminin-derived peptide CQAASIKVAV was covalently immobilized via the Michael addition. The furan- and peptide-modified hyaluronic acid was then cross-linked in situ by mixing with bismaleimide poly(ethylene glycol) at 37 °C to obtain a bioactive hyaluronic acid–based hydrogel. The hyaluronic acid derivatives were characterized by 1H NMR and Fourier transform infrared spectroscopy. The gelation, swelling, and mechanical property of the hydrogels were analyzed. The modulus of the hydrogel could be tuned by changing furan substitution degree, while the peptide concentration could be changed by the ratio of furan- and peptide-modified hyaluronic acid with hyaluronic acid–furan. In vitro culture of PC12 cells showed that the longest neurite outgrowth appeared on the hyaluronic acid–poly(ethylene glycol) hydrogel with the highest peptide content (the substitution degree of peptide in furan- and peptide-modified hyaluronic acid was 23 %) and a lower threshold modulus of 4.5 kPa. The furan and methacrylate-functionalized hyaluronic acid provides a versatile platform for diverse functionalization and can be used for modulation of other cell behaviors as well.

Effect of nanoclay addition on physical, chemical, optical and biological properties of experimental dental resin composites

ObjectiveTo prepare organically modified montmorillonite (OM MMT) and assess mechanical, physical, chemical and biological effects of its introduction into resin-composites. MethodsNatural MMT clay was modified by a methacrylate functionalized quaternary ammonium intercalating agent. Interlayer distance was measured by X-ray diffraction. Dental composites were then prepared with x=0, 1, 2.5, 5 or 7.5wt.% of OM MMT, (75−x) wt.% of silanated barium glass and 25wt.% of methacrylate based matrix). Relative weight loss was measured and the effect of the substitution on mechanical properties was studied by dynamic mechanical analysis and hardness tests. Properties of resin composites were evaluated in terms of water sorption, light transmittance, biological tests and by high-performance liquid chromatography (HPLC). ResultsResin based composites with well-dispersed organically modified MMT were successfully prepared. There were no significant weight loss differences shown by TGA within all samples. The DMA analysis showed that the introduction of clays have a beneficial effect in increasing the storage and elastic modulus of composites. Clay presence was shown to interfere with the blue light transmittance, affecting Vickers hardness and water sorption levels. The amount of released monomers measured from extracts was below expected levels for this type of materials and biological tests show satisfactory cell compatibility. SignificanceThis paper reports the successful functionalization of MMT by a methacrylate group and further incorporation in experimental dental composites. Physical and biological results show a potential interest to the application of nanoclays into dental resin composites.

Oil-in-microgel strategy for enzymatic-triggered release of hydrophobic drugs

Polymer microgels have received considerable attention due to their great potential in the biomedical field as drug delivery systems. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan composed of N-acetyl-d-glucosamine and d-glucuronic acid. This polymer is biodegradable, nontoxic, and can be chemically modified. In this work, a co-flow microfluidic strategy for the preparation of biodegradable HA microgels encapsulating hydrophobic drugs is presented. The approach relies on: (i) generation of a primary oil-in-water (O/W) nanoemulsion by the ultrasonication method, (ii) formation of a double oil-in-water-in-oil emulsion (O/W/O) using microfluidics, and (iii) cross-linking of microgels by photopolymerization of HA precursors modified with methacrylate groups (HA-MA) present in the aqueous phase of the droplets. The procedure is used for the encapsulation and controlled release of progesterone. Degradability and encapsulation/release studies in PBS buffer at 37°C in presence of different concentrations of hyaluronidase are performed. It is demonstrated that enzymatic degradation can be used to trigger the release of progesterone from microgels. This method provides precise control of the release system and can be applied for the encapsulation and controlled release of different types of hydrophobic drugs.

Highly-branched cross-linked poly(ethylene oxide) with enhanced ionic conductivity

Polymers containing poly(ethylene oxide) (PEO) have been investigated for solid electrolytes for lithium-ion batteries, which are preferred to be amorphous and have flexible polymer chains to achieve high Li ion conductivity. This paper reports ionic conductivity in a series of cross-linked PEOs prepared from poly(ethylene glycol) methyl ether acrylate (PEGMEA, monomer) and poly(ethylene glycol) diacrylate (PEGDA, cross-linker) via photopolymerization. The resulting copolymers contain short PEO side chains and thus high content of amorphous PEO. While the cross-linking enhances mechanical strength for solid electrolytes, the introduction of PEGMEA with methoxyl chain end groups decreases Tg and increases ionic conductivity. The use of acrylate groups for polymerization, instead of methacrylate groups, also yields low Tg and thus high conductivity. The effect of PEGMEA content, salt content, and temperature on the ionic conductivity was thoroughly investigated, and it was satisfactorily described using the Vogel-Fulcher-Tammann (VFT) equation. The effectiveness of PEO-based polymers used for solid electrolytes in advanced lithium batteries was also elucidated based on the VFT equation.

New polymers containing BF2-benzoylacetonate groups. Synthesis, luminescence, excimer and exciplex formation

In the present study, a new synthetic method for the functionalization of polystyrene (PS) and (styrene-methyl methacrylate) copolymer has been developed. Using the new method, polymers containing BF2-benzoylacetonate groups have been obtained through double acylation by acetic anhydride with boron trifluoride. Luminescence of the produced polymers in solutions and films has been studied. Quantum yields of polymer solution luminescence are significantly higher than those of the low-molecular-weight analog – boron difluoride benzoylacetonate. For the polymer, in which styrene fragments are separated by methyl methacrylate groups, at low concentrations of the polymer in solution one observes the monomer luminescence of BF2-benzoylacetonate groups, while at high concentrations – the excimer luminescence. In case of PS-based polymers, in which BF2-benzoylacetonate groups and phenyl rings are not separated, in diluted solutions one observes the fluorescence of the intramolecular exciplexes, while at the concentration increase – the luminescence of intermolecular exciplexes. The ability of excimer formation is responsible for the increased photostability of the produced polymers.

Structural characterization of new fluorinated mesogens obtained through halogen-bond driven self-assembly

We describe the synthesis and characterization of new trimeric complexes obtained upon halogen-bond driven self-assembly of 1,4-diiodotetrafluorobenzene or α,ω– diiodoperfluoroalkanes, acting as XB-donors, with an alkoxystilbazole derivative functionalized with a methacrylate terminal group, acting as XB-acceptor. Despite the fact that the starting materials are not mesomorphic in nature, the obtained halogen-bonded complexes exhibit monotropic LC behaviour with smectic A phases possibly resulting from segregation between fluorocarbon and hydrocarbon chains. The obtained supramolecular mesogens possess reactive groups suitable for incorporation into liquid crystalline elastomeric actuators.

Photo-cross-linked perylene diimide derivative materials as efficient electron transporting layers in inverted polymer solar cells.

We present an efficient and stable interfacial material based on a water-soluble perylene diimide derivative functionalized with ionic and methacrylate groups (abbreviated as PDIM), which can be stabilized by the photo-polymerization of diacrylate groups at both ends of the side chain in the PDIM. The characteristics of the photo-cross-linked PDIM films were examined using absorption spectra, cyclic voltammetry, work function, and surface morphology. The feasibility of the photo-cross-linked PDIM films as a novel electron transporting layer (ETL) in polymer solar cells (PSCs) was also investigated. The PTB7-Th:PC71BM-based PSC using the PDIM as the ETL achieved the excellent power conversion efficiency of 9.44% similar to the conventional polyethylenimine ethoxylated (PEIE) and better than ZnO. Furthermore, the PSC with the PDIM films exhibited a similar lifetime to that of the PEIE-based device. This approach suggests that the photo-cross-linked PDIM film could be regarded as a promising interfacial material for fabricating highly efficient PSCs.

Synthesis and characterization of new functionalized polymer-Fe3O4 nanocomposite particles

In this study, Fe3O4 nanoparticles (NPs) were functionalized with copolymer or terpolymer bearing glycidyl methacrylate (GMA) moieties making them suitable for potential applications as drug delivery systems (DDS). For this pur- pose, the surface of magnetic nanoparticles was first coated with 3-(trimethoxysilyl) propyl methacrylate (MPS) by a silaniza- tion reaction to introduce reactive methacrylate groups onto the surface. Subsequently, monomers were grafted onto the sur- face of modified-MPS particles via two polymerization methods: seed emulsion (GMA, divinylbenzene, DVB, and styrene, S) and distillation - precipitation (GMA and DVB). The obtained nanocomposite particles were characterized by FTIR (Fourier transform infrared spectroscopy), DR UV-Vis (diffuse reflectance ultraviolet - visible spectroscopy), TEM (transmission electron microscopy) combined with EDS (energy dispersive X-ray spectroscopy) analysis and DLS (dynamic light scatter- ing). FTIR spectroscopy showed that indeed a polymer - Fe3O4@MPS composite was obtained. TEM and EDS analysis showed that the seed emulsion method resulted in nanosized, 100 nm Fe3O4@MPS core/polymer shell NPs, forming long chains. On the contrary, the distillation - precipitation method caused the formation of an inverted structure, i.e. polymer core coated by a Fe3O4@MPS shell, which exhibited a very coarse size distribution varying from several hundreds to over 2 µm.

A Bioinspired Bioactive Multi-component Polymerizable Material For Dental Restorative Applications; effects Of Calcium Content On Physico Mechanical Properties

Novel inorganic-organic hybrid resins [IOHRs] containing mixture of alkoxides of calcium/magnesium/zinc with polymerizable dimethacrylate groups were synthesised using a simple single-pot modified sol-gel method. Objective of the present study is to investigate the impact of calcium content over bioactivity, polymerization shrinkage, and physico mechanical properties of bioactive IOHR containing mixture of alkoxides of calcium/magnesium/zinc having polymerizable methacrylate groups, along with various fillers they can be used as a dental restorative material. Various formulations with varying concentration of inorganic content were used during the synthesis. The concentration of inorganic content was optimised as 0.1% by weight of with respect to the silane. This optimised formulation based photocured composite [CMZ2] showed better DTS (35-40 MPa), FS (65-70 MPa), VHN (140-146 kg/mm 2 ), possess low shrinkage, non-cytotoxic in nature, bioactive with good cell adhesion and cell proliferation properties. CMZ2 was found to be a potential novel dental composite.

Injectable photo crosslinked enhanced double-network hydrogels from modified sodium alginate and gelatin

Recently, photocrosslinked hydrogels have attracted more and more attention in biomedical applications. In this study, a serials of injectable hydrogels were fabricated from aldehyde methacrylate sodium alginate and amino gelatin (AMSA/AG) using a two-step process. Here, sodium alginate, a kind of natural polysaccharide, was modified by oxidizer to form aldehyde sodium alginate (ASA), and methacrylate groups were further grafted on the main chain of ASA. Gelatin, the denatured form of collagen, was modified with ethylenediamine (ED) to graft more amino groups. When AMSA and AG aqueous solutions were mixed, the Schiff base reaction occurred quickly to form the primary network between aldehyde groups in AMSA and amino groups in AG, and then a 365nm ultraviolet (UV) light was used to initiate the radical reaction of methacrylate groups in AMSA to produce the secondary network. The structures and properties of AMSA/AG hydrogels were evaluated by Fourier Transforms Infrared spectroscopy (FTIR) and 1HNMR analysis. The swelling ratio confirmed the density of crosslinked networks, and the mechanical performance demonstrated that the UV initiated the double crosslinking network hydrogels have an improved mechanical properties compared to the single Schiff base networks hydrogels. The results showed that the photocrosslinked double network hydrogels have enhanced mechanical properties, good biocompatibility and controllable degradation rate. So, this hydrogels may have great potential utilized in regenerative medicine as therapeutic materials.

Biobased Thermosets Prepared from Rigid Isosorbide and Flexible Soybean Oil Derivatives

A rigid monomer, isosorbide-methacrylate (IM), was synthesized from isosorbide with methacrylate anhydride (MAA) via a solvent-free, ultrasonic-assisted method and then was used to copolymerize with acrylated epoxidized soybean oil (AESO) to formulate a biobased thermosetting resin (IM-AESO). The synthesis of IM was monitored by attenuated total reflectance Fourier transform infrared (ATR-FTIR) by tracking the changes in the functional groups of the reaction system. The AESO was further modified with MAA to replace the hydroxyl groups of AESO with methacrylate groups, generating a resin (IM-MAESO) with an improved degree of unsaturation. The chemical structure of IM and modification of AESO with MAA were characterized using 1H NMR, 13C NMR, and ATR-FTIR analyses. The miscibility of IM with AESO was predicted according to Hansen’s solubility theory and evaluated experimentally. The formulated IM-AESO and IM-MAESO resins were compared with the pure AESO and IM resins in terms of their rheological behaviors,...

Thermodynamic properties of three-dimensional radical polymerization of dimethacrylates and their relation to the structure and properties of network polymers

For the polymerization of dimethacrylates, thermodynamic properties related to effect of the formed network polymer on the reaction between pendant methacrylate groups and free radicals have been studied. The polymer matrix creates steric hindrances for this reaction and impedes the shrinkage process accompanying the opening of С=С bonds. As a result, internal stresses develop in the polymer, the heat of polymerization of methacrylate groups decreases compared with the polymerization of methyl methacrylate, and the full conversion of double bonds is prevented. The relaxation of internal stresses and of excess free volume leads to the spontaneous cracking of network polymers and causes formation of regular adhesive-shrinkage patterns. The process of superslow relaxation of internal stresses in polymer films has been ascertained, and the mechanochemical model of this process has been advanced. The effect of internal stresses on the physicomechanical properties of polydimethacrylates has been discussed.

Synthesis and properties of carboxy derivative of Epidian 6 monomethacrylate

We present the synthesis of an oligomer with carboxy and methacrylic groups based on Epidian 6. The effect of the catalyst nature and amount, solvent nature and process temperature on the rate of the reaction between Epidian6 monomethacrylate and adipic acid was examined at 313, 323 and 333 K in the presence of 4-dimethylaminopyridine, 1,4-diazobicyclo[2.2.2]octane, and benzyltriammonium chloride. The synthesized oligomer was characterized using chemical and IR-spectroscopic analyses. We suggest the use of the synthesized product as an active additive to epoxy-oligoesteric blends based on Epidian 5. The chemistry of the film forming process has been determined using IR-spectroscopy.

Easily Accessible Thermotropic Hydrogen-Bonded Columnar Discotic Liquid Crystals from Fatty Acid- Tris-Benzoimidazolyl Benzene Complexes.

We report the formation of easily accessible hydrogen‐bonded columnar discotic liquid crystals (LCs) based on tris‐benzoimidazolyl benzene (TBIB) and commercially available fatty acids. By increasing the length of the fatty acid, the temperature range of liquid crystallinity was tuned. Introducing double bonds in octadecanoic acid lowered the crystallization temperature and increased the temperature range of the mesophase. Surprisingly, dimerized linoleic acid also forms an LC phase. When using branched aliphatic acids with the branching point close to the acid moiety, the mesophase was lost, whereas phosphonic acid or benzenesulfonic acid derivatives did have a mesophase, showing that the generality of this approach extends beyond carboxylic acids as the hydrogen‐bond donor. Furthermore, a polymerizable LC phase was obtained from mixtures of TBIB with a methacrylate‐bearing fatty acid, providing an approach for the fabrication of nanoporous polymer films if the methacrylate groups are polymerized. Finally, the higher solubility of methyl‐TBIB was used to suppress phase separation in stoichiometric mixtures of the template molecule with fatty acids.

Temperature responsive chemical crosslinkable UV pretreated hydrogel for application to injectable tissue regeneration system via differentiations of encapsulated hMSCs

An injectable hydrogel showing temperature-dependent chemical crosslinking was developed to combine injectabilities of physical hydrogels with dense structures of chemical hydrogels for applications in stem cell delivery-mediated tissue regeneration systems showing easy administration and maintenance of well-dispersed cells within the hydrogel. Hydrophobic methacryl groups were applied to thermosensitive poly(organophosphazenes) to induce temperature mediated hydrophobic interaction and chemical crosslinking. UV pretreated polymer solution showed chemical crosslinking not before injection only after injection into the body even it was already exposed to UV. As this injectable hydrogel showed small pore-sizes, it was guessed cell holding without any adhesive moieties were available and showed the potentials for a cell scaffold. In this study, temperature dependent chemical crosslinking and proliferation and differentiation of the encapsulated hMSCs into various tissues were observed in the hydrogels after injection.

Gel Polymer Electrolytes Containing Anion-Trapping Boron Moieties for Lithium-Ion Battery Applications.

Gel polymer electrolytes (GPEs) based on semi-interpenetrating polymer network (IPN) structure for lithium-ion batteries were prepared by mixing boron-containing cross-linker (BC) composed of ethylene oxide (EO) chains, cross-linkable methacrylate group, and anion-trapping boron moiety with poly(vinylidene fluoride) (PVDF) followed by ultraviolet light-induced curing process. Various physical and electrochemical properties of the GPEs were systematically investigated by varying the EO chain length and boron content. Dimensional stability at high temperature without thermal shrinkage, if any, was observed due to the presence of thermally stable PVDF in the GPEs. GPE having 80 wt % of BC and 20 wt % of PVDF exhibited an ionic conductivity of 4.2 mS cm-1 at 30 °C which is 1 order of magnitude larger than that of the liquid electrolyte system containing the commercial Celgard separator (0.4 mS cm-1) owing to the facile electrolyte uptake ability of EO chain and anion-trapping ability of the boron moiety. As a result, the lithium-ion battery cell prepared using the GPE with BC showed an excellent cycle performance at 1.0 C maintaining 87% of capacity during 100 cycles.