Multifunctional Resin Research Articles

Fluorescent zinc acrylate resins containing coumarin structures with enhanced antifouling performance

The demand for non-toxic antifouling coatings has led to the development of multifunctional antifouling coatings. In this work, a series of coumarin acids with fluorescence were first prepared via the Knoevenagel condensation reaction. Then, multifunctional zinc acrylate resins were produced successfully by employing an acrylic acid monomer, ZnO, and coumarin acids by free radical polymerization and polycondensation processes. The self-polishing and antifouling properties of the resins were investigated by dynamic simulation experiments, E. coli growth inhibition experiments, algae adhesion inhibition experiments, and marine environment antifouling experiments. The results show that the zinc acrylate resins containing the coumarin structures not only have good self-polishing performance but also have better antifouling performances than the zinc acrylate resin containing benzoic acid. This work not only reveals the antifouling mechanism of the multifunctional resins, but also provides a new strategy for the development of environmentally friendly antifouling coatings.

An Integrated Multi-Functional Thermal Conductive and Flame Retardant Epoxy Composite with Functionalized Carbon Nitride Nanosheets.

In miniaturized and integrated electronic devices, thermal potential and fire hazards caused by heat diffusion require an efficient thermal management system with versatile electronic packaging equipment. The flame retardancy was endowed on the surface of carbon nitride after thermal etching (CNNS) containing piperazine pyrophosphate (PPAP) by hydrogen bonding, and the obtained nanosheet was defined as PPAP-CNNS. During solution blending and program-controlled curing, PPAP-CNNS was used as a multifunctional filler to fabricate highly thermoconductive and fire retardant epoxy resin (EP) composites. In line with expectations, the resultant EP composites containing 7 wt% PPAP-CNNS had an exceptional thermal conductivity (TC) of 1.1 W·m-1K-1, which was 4.8 times higher than pure EP. Simultaneously, there was a sharp drop in the heat release rate (HRR), total heat release (THR), smoke production rate (SPR), and total smoke production (TSP) compared to pure EP. These reductions were, respectively, 63.7%, 54.2%, 17.9%, and 57.2%. The addition of PPAP-CNNS increased the specific surface area, which increased the heat conduction routes, and also the shape of the compact and solid char layer during burning, protecting the underlying polymer. These improvements to dispersion and surface functionalization were made possible by the compound. These results indicate that the preparation of integrated multi-functional resin described in this study has a wide application.

Multifunctional dental resin composite with antibacterial and remineralization properties containing nMgO-BAG

The inherent characteristics of resin composite can lead to micro-leakage after polymerization shrinkage. The bacteria invasion through edge micro-leakage and attachment onto the material surface can cause secondary caries, reducing the service life of resin composites. In this study, magnesium oxide nanoparticles (nMgO) as an inorganic antimicrobial agent and bioactive glass (BAG) as a remineralization agent were simultaneously incorporated into the resin composite. With the addition of both nMgO and BAG, the resin composite showed an excellent antimicrobial effect compared to the resin composite with nMgO or BAG only. The remineralization capacity of demineralized dentin increased with the increasing content of BAG. Vickers hardness, compressive strength, and flexural strength of the resin composite with nMgO-BAG were not significantly affected compared to the ones with the same total filler amount but with BAG only. The depth of cure and water sorption values of the resin composite showed an increasing trend with the increasing total amount of nMgO and BAG fillers. This developed multifunctional resin composite is expected to reduce bacterial invasion and promote remineralization of early caries damage.

Novel antibacterial dental resin containing silanized hydroxyapatite nanofibers with remineralization capability.

Secondary caries is the primary issue that causes restoration failure. The objectives of this study were to: (1) synthesize silanized hydroxyapatite nanofibers loaded with erythromycin (s-HAFs@EM); (2) evaluate the mechanical property, antibacterial activity, and remineralization capability of the novel dental resin containing s-HAFs@EM. s-HAFs were prepared by the solvothermal approach and loaded with EM. Characterization and antibacterial activity were evaluated. Subsequently, s-HAFs@EM were incorporated into dental resin at different mass fractions (5 %, 10 %, 15 %, and 20 %), and then they were submitted to characterization, including mechanical property, antibacterial activity, remineralization capability, and cytotoxicity. s-HAFs@EM were successfully synthesized, and they exhibited excellent antibacterial activity. Resin containing 15 % s-HAFs@EM exhibited the best flexural strength (118.67±15.71MPa) and elastic modulus (2.02±0.30GPa) (P<0.05), which were increased by 65.43 % and 90.7 %, compared to those of neat resin, respectively. Resin with 15-20 % s-HAFs@EM showed high antibacterial rate (>85 %) when compared control group (P<0.05). Furthermore, resin also exhibited a definite remineralization capability and good biosafety in vitro. This novel multifunctional resin with improved mechanical property, desirable antibacterial activity and remineralization capability is promising to combat secondary caries.

Vibro-acoustic characteristics of multifunctional carbon fiber reinforced panel

This paper deals with the assessment of vibro-acoustic properties of a multifunctional carbon fiber reinforced panel manufactured by bulk infusion, a modified resin film infusion process. The components of the epoxy resin were chosen to contrast the electrical insulating property and poor flame resistance of the epoxy resins impregnating carbon woven fabric. To confer electrical conductivity to the resin a percentage of 0.5 wt% of Multi-Wall Carbon Nanotubes (MWCNTs) was dispersed in the resin, whereas to increase flame resistance a percentage of 5 wt% of Glycidil Polyhedral Oligomeric Silsesquioxanes (GPOSS) was solubilized in the epoxy mixture. Furthermore, as hardener agents, a mixture of 4,4’-DiaminoDiphenyl Sulfone (DDS) (53.4 wt%) and Bis(3-Aminophenyl) Methyl Phosphine Oxide (BAMPO) (46.7 wt%) was used. The values of the electrical conductivity were found satisfactory enough, being 4.02 × 10−2 S/m for the multifunctional resin and 1.39 × 104 S/m for the in-plane conductivity of the panel, whereas the Limiting Oxygen Index (LOI) value of the multifunctional resin was found to increase from 27% to 36%. Considering these promising results, an experimental assessment of the vibro-acoustic properties of the manufactured multifunctional panel was also performed. The panel was tested mainly to evaluate its low-frequency vibration damping and sound insulation characteristics. The manufactured panel demonstrated an improved efficiency if compared to a baseline configuration, presenting almost the double modal damping and a gain of 10 dB on the global noise reduction.

High-Performance Properties of an Aerospace Epoxy Resin Loaded with Carbon Nanofibers and Glycidyl Polyhedral Oligomeric Silsesquioxane

This paper proposes a new multifunctional flame retardant carbon nanofiber/glycidyl polyhedral oligomeric silsesquioxane (GPOSS) epoxy formulation specially designed for lightweight composite materials capable of fulfilling the ever-changing demands of the future aerospace industry. The multifunctional resin was designed to satisfy structural and functional requirements. In particular, this paper explores the advantages deriving from the combined use of GPOSS and CNFs (short carbon nanofibers) to obtain multifunctional resins. The multifunctional material was prepared by incorporating in the epoxy matrix heat-treated carbon nanofibers (CNFs) at the percentage of 0.5 wt% and GPOSS compound at 5 wt% in order to increase the mechanical performance, electrical conductivity, thermal stability and flame resistance property of the resulting nanocomposite. Dynamic mechanical analysis (DMA) shows that the values of the Storage Modulus (S.M.) of the resin alone and the resin containing solubilized GPOSS nanocages are almost similar in a wide range of temperatures (from 30 °C to 165 °C). The presence of CNFs, in the percentage of 0.5 wt%, determines an enhancement in the S.M. of 700 MPa from −30 °C to 180 °C with respect to the resin matrix and the resin/GPOSS systems. Hence, a value higher than 2700 MPa is detected from 30 °C to 110 °C. Furthermore, the electrical conductivity of the sample containing both GPOSS and CNFs reaches the value of 1.35 × 10−1 S/m, which is a very satisfying value to contrast the electrical insulating property of the epoxy systems. For the first time, TUNA tests have been performed on the formulation where the advantages of GPOSS and CNFs are combined. TUNA investigation highlights an electrically conductive network well distributed in the sample. The ignition time of the multifunctional nanocomposite is higher than that of the sample containing GPOSS alone of about 35%.

Synthesis of Epoxy Methacrylate Resin and Coatings Preparation by Cationic and Radical Photocrosslinking.

This work involves the synthesis of hybrid oligomers based on the epoxy methacrylate resin. The EA resin was obtained by the modification of industrial-grade bisphenol A-based epoxy resin and methacrylic acid has been synthesized in order to develop multifunctional resins comprising both epoxide group and reactive, terminal unsaturation. Owing to the presence of both epoxy and double carbon–carbon pendant groups, the reaction product exhibits photocrosslinking via two distinct mechanisms: (i) cationic ring-opening polymerization and (ii) free radical polymerization. Monitoring of EA synthesis reactions over time using PAVs, MAAC and NV parameters, and the FT-IR method reveals that esterification reactions proceed faster at the start, exhibiting over 40% of conversion within the initial 60 min, which can be associated with a relatively high concentration of reactive sites and low viscosity of the reaction mixture at the initial reaction stage. With the further increase in the reaction time, the reaction rate tends to decrease. The control of the EA synthesis process can guide how to adjust reactions to obtain EAs with desired characteristics. Based on obtained values, one can state that the optimum synthesis time of about 4–5 h should be adopted to prepare EAs having both epoxy groups and unsaturated double bonds. The structure of the obtained EA was confirmed by FT-IR and NMR methods, as well as the determination of partial acid value and epoxy equivalent. Samples at various stages of synthesis were cured with UV radiation in order to study the kinetics of the process according to cationic and radical polymerization determined via photo-differential scanning calorimetry (photo-DSC) and real-time infrared spectroscopy (RT-IR) and then the properties of the cured coatings were tested. It turned out that the cationic polymerization was slower with a lower conversion of the photoreactive groups, as compared to the radical polymerization. All the obtained EA coatings were characterized by good properties of cured coatings and can be successfully used in the coating-forming sector.

Thermal conductivities and mechanical properties of epoxy resin as a function of the degree of cross-linking

Epoxy resins are widely used polymer matrices for numerous applications. Despite substantial advances, the molecular-level knowledge-base required to exploit these materials to their full potential remains limited. A deeper comprehension of structure/property relationships in epoxy resins at the molecular level is critical to progressing these efforts. It can be laborious, if not impractical, to elucidate these relationships based on experiments alone, particularly in aiding the search for new, multi-functional resins. Here, molecular dynamics simulations are used to calculate, compare, and elucidate connections between both thermal conductivities and mechanical properties of an exemplar epoxy resin, Bisphenol F cross-linked with Diethyl Toluene Diamine, as a function of degree of cross-linking. Both the elastic modulus and thermal transport of the resin show an increase with greater cross-linking. Specifically, decomposition of the thermal conductivity into different force contributions suggests that although the bonded term contributes to an increase in the heat flux as a function of cross-linking, the contributions from non-bonded interactions suggest a less predictable trend. These outcomes provide a foundation for designing customized epoxy resins with both desirable thermal and mechanical attributes.

Mechanically Robust and Reprocessable Acrylate Vitrimers with Hydrogen-Bond-Integrated Networks for Photo-3D Printing.

Reprocessable acrylate vitrimer needs to enhance its strength to expand the application in photo-three-dimensional (photo-3D) printing. However, the methods for improving mechanical properties by the addition of nanofillers or a multifunctional resin into acrylate vitrimers are inappropriate for photo-3D printing due to the low curing speed of photopolymerization induced by weakening light transmittance or reduction of dimensional accuracy caused by large shrinkage. At present, we demonstrate a new strategy for developing a kind of mechanically robust and reprocessable 3D printing thermosets by combining hydrogen bonds and exchangeable β-hydroxyl esters into acrylate vitrimers. To realize this purpose, diacrylate prepolymer containing β-hydroxyl esters was first synthesized from glycidyl methacrylate and suberic acid. Then, the resin formulations for 3D printing comprising the synthesized diacrylate prepolymer together with acrylamide generate exchanged β-hydroxyl ester and pendent amide in cross-linked networks. Here, hydrogen bonds resulting from the amide group as sacrificial bonds dissipate vast mechanical energy under an external load. With the inclusion of 20 wt % acrylamide, the average tensile strength and Young's modulus are up to 40.1 and 871 MPa, which increased by about 4.4 and 3.85 times, respectively. The network rearrangement of cross-linked vitrimers can be achieved through the dynamic ester exchange reactions with gradual disappearance of hydrogen bonds at elevated temperatures, imparting reprocessability into the printed structures. Various photo-3D printing or UV irradiation shapes were successfully produced, and these dissolved in ethylene glycol could be remolded again.

Design of Multifunctional Composites: New Strategy to Save Energy and Improve Mechanical Performance.

In this paper, an alternative curing strategy, based on the application of an electric field, is proposed to harden nano-filled multifunctional resins. The resin is obtained through the dispersion of carbon nanotubes, which act as nanometric heater elements in the epoxy matrix. The electro-curing is activated by applying an external electric voltage, which allows tunable cross-linking within the epoxy matrix entrapped between the nanotubes. The electro-curing method allows reaching higher curing degrees with respect to the conventional ones and, consequently, higher glass transition temperatures. This is a direct consequence of the fact that the curing reactions start directly in the regions at the interphase between carbon nanotubes, acting as heater nano-filaments, and the polymeric matrix. The proposed method is able to give composites better properties, making the curing process fast and energy-saving.

Lignocellulosic Natural Fiber Reinforced Bisphenol F Epoxy Based Bio-composites: Characterization of Mechanical Electrical Performance

ABSTRACT The current research deals with bio-composites developed by using four different types of lignocellulosic natural fibers, e.g., jute, sisal, coconut/coir, and sugarcane (bagasse) for reinforcement. A multifunctional resin derived from phosphoric acid modified Diglycidylether of bisphenol-F (DGEBF) was used as a matrix. Mechanical properties, e.g., impact strength, flexural strength, tensile strength, and modulus etc. were evaluated and analyzed. Among all the different types of samples developed, sisal and jute fiber-based composites exhibit superior tensile, impact, and flexural properties as compared to other fiber types investigated. Bagasse composites exhibit the highest specific bending performance due to lowest density. Coir and bagasse-reinforced composites show higher electrical resistivity due to lower fiber density and lower crystallinity of fibers. Relatively higher resistivity suggests application in small switches, insulation rods, mobile/laptop, and computer covers etc. The results from the developed samples demonstrate that lignocellulosic fiber-reinforced epoxy composites could open new opportunities for their applications in different electrical goods and as an environmentally friendly alternative.

Study on the preparation and properties of new environmentally friendly antifouling acrylic metal salt resins containing indole derivative group

An indole derivative containing a carbon-carbon double bond was purposefully synthesized by the Friedel-Crafts reaction based on 6-chlorine-1H-indole and characterized by IR, 1H NMR and 13C NMR. Antibacterial and inhibiting algae attachment experiments were carried out on the indole derivative. The indole derivative was indicated to have good antibacterial and algae inhibiting properties, then, was introduced into acrylic metal salt resin. Multifunctional acrylic metal salt resins were synthesized via free radical polymerization and polycondensation reactions using acrylic monomers, the indole derivative, metal salts and naphthenic acid. The synthesized resins were characterized by IR and 1H NMR, and the results showed that these target products were successfully synthesized. The self-polishing and antifouling properties of the multifunctional resins were investigated through inhibiting algae attachment experiment, dynamic simulation experiment, anti-protein adsorption experiment and antifouling test in marine environment. Acrylic metal salt resins containing the indole derivative were proven to have not only self-polishing properties but also better antifouling performance than pure acrylic metal salt resins.

Differential adsorption of zwitterionic PPCPs by multifunctional resins: The influence of the hydrophobicity and electrostatic potential of PPCPs.

Zwitterionic pharmaceuticals and personal care products can interact with adsorbents in different ways due to their various properties. In this work, the effects of hydrophobicity and electrostatic potential were explored through the adsorption of ciprofloxacin (CPX) and tetracycline (TC) onto multifunctional resins. Nonionic surface interaction was dominant for the adsorption on high-surface-area resin GMA10. Thereinto, hydrophobic and π-π interaction dominant for hydrophobic CPX and hydrophilic TC, respectively. Electrostatic interaction played an important role for high-anion-exchange-capacity resin GMA90. Upon their adsorption onto GMA50 resin, the relatively separated positive and negative electrostatic potentials of CPX+- due to the greater distance (∼12.33 Å) between the anionic and cationic groups led to electrostatic attraction and interaction (Ea = 8.64 ± 0.31 kJ/mol) and the vertical orientation of molecule on the surface. However, TC+-0 displayed nonionic surface interaction (Ea = 7.96 ± 0.14 kJ/mol) due to its relatively neutral electrostatic potential arising from the adjacent functional groups. Hence, the surface of GMA50 was covered with TC+-0 molecules adsorbed parallel to the surface, thereby restricting TC+-0 adsorption. Coexisted with monovalent salts, CPX adsorption was facilitated due to the salting-out effect. By contrast, the salting-out effect for TC was extremely weak, and TC adsorption was restrained due to the competitive adsorption of salts.

Multi-functional Resin Coated Sand Proppants: Examination using Microscopy and Energy Dispersive X-ray Spectroscopy

Multi-functional Resin Coated Sand Proppants: Examination using Microscopy and Energy Dispersive X-ray Spectroscopy

Novel Protein-Repellent and Antibacterial Resins and Cements to Inhibit Lesions and Protect Teeth

Orthodontic treatment is increasingly popular as people worldwide seek esthetics and better quality of life. In orthodontic treatment, complex appliances and retainers are placed in the patients’ mouths for at least one year, which often lead to biofilm plaque accumulation. This in turn increases the caries-inducing bacteria, decreases the pH of the retained plaque on an enamel surface, and causes white spot lesions (WSLs) in enamel. This article reviews the cutting-edge research on a new class of bioactive and therapeutic dental resins, cements, and adhesives that can inhibit biofilms and protect tooth structures. The novel approaches include the use of protein-repellent and anticaries polymeric dental cements containing 2-methacryloyloxyethyl phosphorylcholine (MPC) and dimethylaminododecyl methacrylate (DMAHDM); multifunctional resins that can inhibit enamel demineralization; protein-repellent and self-etching adhesives to greatly reduce oral biofilm growth; and novel polymethyl methacrylate resins to suppress oral biofilms and acid production. These new materials could reduce biofilm attachment, raise local biofilm pH, and facilitate the remineralization to protect the teeth. This novel class of dental resin with dual benefits of antibacterial and protein-repellent capabilities has the potential for a wide range of dental and biomedical applications to inhibit bacterial infection and protect the tissues.

Fabrication of UV curable adhesive for narrow bezel liquid crystal device using multi-functional cross-linkable resin

Liquid crystal (LC) devices used in 3D or tile displays require a narrow bezel design to provide seamless characteristics. Adhesives for these devices require excellent mechanical properties and low LC pollution level. Reactive resins are significant components of adhesives used in LC display and play a key role in inducing adhesion. In this study, a new UV curable adhesive for a narrow bezel LC device was fabricated by introducing a multi-functional cross-linkable resin. The proposed adhesive was found to provide excellent mechanical properties and low levels of LC contamination by forming a dense cross-linked structure.

The effect of reactive diluent on mechanical properties and microstructure of epoxy resins

The effects of an aliphatic reactive diluent on the viscosity, gel time, chemical resistance, mechanical properties, fracture toughness, microstructure and relaxations of two different epoxy resins, i.e., a bifunctional and a multifunctional epoxy, were investigated. The gel time was not significantly affected by the diluent. The modulus and ultimate strength gradually declined, while the ductility steadily increased as the diluent content was increased. The failure mode of epoxy samples under flexural test changed from brittle to much more ductile upon the progressive incorporation of diluent into the epoxy resins. The strain at break of bifunctional resin improved by 75%, while that of multifunctional resin enhanced by more than 24%. The dynamic mechanical thermal analysis (DMTA) showed that the introduction of reactive diluent into different epoxy resins reduced the storage modulus at the glassy region and significantly broadened the glass transition region of the epoxy matrices with approximately no change in the glass transition temperature. The DMTA results also indicated increased microstructural heterogeneities upon the addition of diluent to the epoxy resins as evidenced by atomic force microscopy. The fracture toughness of epoxy resins enhanced with diluent content, about 20% and 29% increase for bifunctional and multifunctional resins, respectively. This was attributed to the improved material’s ductility and activation of plastic deformation in the epoxy resins upon the addition of reactive diluent.

Development of self-healing multifunctional materials

Abstract Reversible hydrogen bonds determined by interaction between epoxy resin and nanocages of polyhedral oligomeric silsesquioxane (POSS) compound have been employed to activate self-healing mechanisms integrated in thermosetting multifunctional materials. The phase composition of the multifunctional resin containing embedded multiwalled carbon nanotubes (MWCNT) can be advantageously exploited to enhance the healing efficiency up to 400%. The presence of MWCNT is responsible of a greater mobility of chains belonging to domains finely interpenetrated in the matrix where the reversible hydrogen bonds can provide enhanced healing efficiency.

Effect of humic acid on ciprofloxacin removal by magnetic multifunctional resins

Background organic matter significantly influences the removal of emerging contaminants in natural water. In this work, the adsorption of ciprofloxacin (CPX) onto a series of magnetic multifunctional resins (GMA10-GMA90) in the presence and absence of humic acid (HA) was conducted to demonstrate the effect of HA. Both hydrophobic and ion exchange interactions contributed to CPX adsorption. Negative charge-assisted hydrogen bonds also participated in the adsorption process, resulting in the high adsorption amount of anionic CPX onto the negatively charged GMA30 under basic solutions. HA could impact CPX adsorption not only as a competitive adsorbate but also as an additional adsorbent. At pH 5.6, the additional adsorption sites provided by adsorbed HA molecules on the resins dominated and thus facilitated the adsorption process. While at pH 10, HA inhibited the adsorption of CPX by directly competing for ion exchange sites and coexisting with CPX in the solution. The ratio of the amount of CPX adsorbed by dissolved HA to that by the resin reached as high as 1.61 for GMA90. The adsorbed HA molecules onto the resins could provide additional adsorption sites for CPX as proven by the enhanced CPX adsorption in HA-preloading systems at pH 5.6.

Nanopore-based electrical and label-free sensing of enzyme activity in blood serum.

A generic strategy to expand the analytical scope of electrical nanopore sensing is presented. We specifically and electrically detect the activity of a diagnostically relevant hydrolytic enzyme and remove the analytically harmful interference from the biochemically complex sample matrix of blood serum. Our strategy is demonstrated at the example of the renin protease which is involved in regulation of blood pressure. The analysis scheme exploits a new approach to reduce sample complexity while generating a specific read-out signal. Within a single spin-column (i), the protease cleaves a resin-tethered peptide substrate (ii) which is affinity-purified using the same multifunctional resin to remove interfering blood serum components, followed by (iii) detecting the peptide via electrical nanopore recordings. Our approach is beneficial in several ways. First, by eliminating serum components, we overcome limitations of nanopore sensing when challenging samples lead to membrane instability and a poor signal-to-noise ratio. Second, the label-free sensing avoids drawbacks of currently used radiolabel-immunoassays for renin. Finally, the strategy of simultaneous generation and purification of a signal peptide within a multifunctional resin can very likely be expanded to other hydrolytic enzymes dissolved in any analyte matrix and exploited for analytical read-out methods other than nanopore sensing.