Trifunctional Monomer Research Articles

Effect of Chemical Structure and Degree of Branching on the Stability of Proton Exchange Membranes Based on Sulfonated Polynaphthylimides.

Hydrolytic stability and oxidative stability are the core properties of sulfonated polynaphthylimides (SPIs) as proton exchange membranes. The chemical structure of SPIs directly influences the performance. Herein, three different series of branched SPIs were designed and prepared using 1,3,5-tris (2-trifluoromethyl-4-aminophenoxy) benzene as a trifunctional monomer and three non-sulfonated diamine monomers, such as 4,4′-oxydianiline (ODA), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (6FODA), and 4,4′-(9-fluorenylidene)dianiline (BFDA). The effect of the chemical structure and degree of branching on SPIs properties is discussed. The results showed that by controlling the chemical structure and degree of branching, the chemical stability of SPIs changed significantly. SPI-6FODA with two ether linkages and a hydrophobic CF3 group has higher hydrolytic stability than SPI-ODA with only one ether linkage. In addition, with the increase of the introduced B3 monomer, the oxidation stability of SPI-6FODA has been greatly improved. We successfully synthesized SPIs with a high hydrolytic stability and oxidative stability.

The Introduction of the Radical Cascade Reaction into Polymer Chemistry: A One-Step Strategy for Synchronized Polymerization and Modification.

SummaryPolymerization and modification play central roles in polymer chemistry and are generally implemented in two steps, which suffer from the time-consuming two-step strategy and present considerable challenge for complete modification. By introducing the radical cascade reaction (RCR) into polymer chemistry, a one-step strategy is demonstrated to achieve synchronized polymerization and complete modification in situ. Attributed to the cascade feature of iron-catalyzed three-component alkene carboazidation RCR exhibiting carbon-carbon bond formation and carbon-azide bond formation with extremely high efficiency and selectivity in one step, radical cascade polymerization therefore enables the in situ synchronized polymerization through continuous carbon-carbon bond formation and complete modification through carbon-azide bond formation simultaneously. This results in a series of α, β, and γ poly(amino acid) precursors. This result not only expands the methodology library of polymerization, but also the possibility for polymer science to achieve functional polymers with tailored chemical functionality from in situ polymerization.

Novel Bio-Based Epoxy Thermosets Based on Triglycidyl Phloroglucinol Prepared by Thiol-Epoxy Reaction.

The pure trifunctional glycidyl monomer from phloroglucinol (3EPO-Ph) was synthesized and used as feedstock in the preparation of novel bio-based thermosets by thiol-epoxy curing. The monomer was crosslinked with different commercially available thiols: tetrafunctional thiol (PETMP), trifunctional thiol (TTMP) and an aromatic dithiol (TBBT) as curing agents in the presence of a base. As catalyst, two different commercial catalysts: LC-80 and 4-(N,N-dimethylamino) pyridine (DMAP) and a synthetic catalyst, imidazolium tetraphenylborate (base generator, BG) were employed. The curing of the reactive mixtures was studied by using DSC and the obtained materials by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The results revealed that only the formulations catalyzed by BG showed a latent character. Already prepared thermosetting materials showed excellent thermal, thermomechanical and mechanical properties, with a high transparency. In addition to that, when compared with the diglycidyl ether of bisphenol A (DGEBA)/PETMP material, the thermosets prepared from the triglycidyl derivative of phloroglucinol have better final characteristics and therefore this derivative can be considered as a partial or total renewable substitute of DGEBA in technological applications.

Electropolymerized Porous Polymer Films on Flexible Indium Tin Oxide Using Trifunctional Furan Substituted Benzene Conjugated Monomer for Biosensing

In recent years, conducting polymers are playing a significant role in the field of display devices, transistors, solar cells, sensors, and electrochromic windows due to their outstanding optoelectronic and semiconducting properties due to their conjugated backbone. One potential application that is not as widely explored using these materials is biosensing, where advantage is taken of the porosity that can be generated by the polymerization of a three-dimensional network. There are various approaches for producing conjugated microporous polymers using trifunctional or multifunctional monomers synthesized via chemical or electrochemical methods. In this work, we have used electropolymerization to synthesize conjugated polymer films on a working electrode of flexible indium tin oxide (FITO) using a trifunctional conjugated monomer 1,3,5-tri(furan-2-yl)benzene (TFB). There are several parameters that influence the formation of a porous polymer film, and the most critical ones are substrate conductivity, roughness, method of electropolymerization, and choice of an electrolyte. These porous electropolymerized films were characterized using UV–vis spectroscopy (UV–vis), X-ray photoelectron spectroscopy (XPS), surface profilometry, four-point probe conductivity measurements, and scanning electron microscopy (SEM). The polymer films that were electropolymerized using chronoamperometry rather than repetitive potential cycling demonstrated a more suitable morphology to trap DNA/RNA analytes for biosensing applications.

Model of hyperbranched polymers prepared via polymerization of AB2 and core C3 monomers in a continuous-stirred tank reactor

The formation of hyperbranched polymers (HBPs) generated by the stepwise polymerization of AB2 monomers with the addition of trifunctional core monomers in a continuous-stirred tank reactor, CSTR, was investigated by a kinetic model. The dependency of the degree of polymerization (DP), the degree of branching (DB), and conversion on the Damköhler number (Da) were calculated by a generating function method. When using the polymerization system without the core monomers, the process could be halted due to the production of larger molecules at the conversion of group A, α(A), of approximately 0.44. The addition of core monomers with high reactivity in the CSTR could retard the growth of polymers. Consequently, the reduced weight-average DP and DB could reach 1000 and 0.51, respectively, at a high α(A) of 0.91. Moreover, the amount of unreacted monomers remaining in the flow exiting the CSTR was much less than that without the addition of the core monomers.

Polyglycerol Hyperbranched Polyesters: Synthesis, Properties and Pharmaceutical and Biomedical Applications.

In a century when environmental pollution is a major issue, polymers issued from bio-based monomers have gained important interest, as they are expected to be environment-friendly, and biocompatible, with non-toxic degradation products. In parallel, hyperbranched polymers have emerged as an easily accessible alternative to dendrimers with numerous potential applications. Glycerol (Gly) is a natural, low-cost, trifunctional monomer, with a production expected to grow significantly, and thus an excellent candidate for the synthesis of hyperbranched polyesters for pharmaceutical and biomedical applications. In the present article, we review the synthesis, properties, and applications of glycerol polyesters of aliphatic dicarboxylic acids (from succinic to sebacic acids) as well as the copolymers of glycerol or hyperbranched polyglycerol with poly(lactic acid) and poly(ε-caprolactone). Emphasis was given to summarize the synthetic procedures (monomer molar ratio, used catalysts, temperatures, etc.,) and their effect on the molecular weight, solubility, and thermal and mechanical properties of the prepared hyperbranched polymers. Their applications in pharmaceutical technology as drug carries and in biomedical applications focusing on regenerative medicine are highlighted.

Preparation and Deep Characterization of Composite/Hybrid Multi-Scale and Multi-Domain Polymeric Microparticles.

Polymeric microparticles were produced following a three-step procedure involving (i) the production of an aqueous nanoemulsion of tri and monofunctional acrylate-based monomers droplets by an elongational-flow microemulsifier, (ii) the production of a nanosuspension upon the continuous-flow UV-initiated miniemulsion polymerization of the above nanoemulsion and (iii) the production of core-shell polymeric microparticles by means of a microfluidic capillaries-based double droplets generator; the core phase was composed of the above nanosuspension admixed with a water-soluble monomer and gold salt, the shell phase comprised a trifunctional monomer, diethylene glycol and a silver salt; both phases were photopolymerized on-the-fly upon droplet formation. Resulting microparticles were extensively analyzed by energy dispersive X-rays spectrometry and scanning electron microscopy to reveal the core-shell morphology, the presence of silver nanoparticles in the shell, organic nanoparticles in the core but failed to reveal the presence of the gold nanoparticles in the core presumably due to their too small size (c.a. 2.5 nm). Nevertheless, the reddish appearance of the as such prepared polymer microparticles emphasized that this three-step procedure allowed the easy elaboration of composite/hybrid multi-scale and multi-domain polymeric microparticles.

Effect of trifunctional planar monomer on the structure and properties of polyamide membranes

Pararosaniline (PAR) was successfully introduced into polyamide network aiming to optimize the structure and properties of polyamide nanofilms. The synthesis of the free-standing polyamide nanofilms was performed on agarose hydrogel supports by interfacial polymerization using 1,3-phenylenediamine (MPD) and PAR as aqueous-phase monomers. The structure and properties of the resultant polyamide nanofilms were systematically analyzed. Atomic force microscopy analysis indicated that PAR can greatly improve the mechanical strength of the polyamide nanofilms. Young’s modulus of the polyamide (PA) nanofilms increases about 1.5 times with the introduction of PAR units in the polyamide network. Strikingly, scratching resistance of the composite membranes was obviously improved through incorporating the polyamide nanofilms containing PAR units. The loss in salt rejection of the composite membranes after scratching is approximately three times lower than that of the membranes without using PAR. Both of the nanofilm thickness and contact angle increase with the increase of PAR, while the effect of PAR on the surface roughness behaves opposite. Using porous polysulfone (PS) membranes as supports, composite membranes comprising the polyamide nanofilms prepared from 0.015 wt% PAR shows higher water flux and salt rejection as compared to that of the nanofilms without PAR.

Tri-functional phthalonitrile monomer as stiffness increasing additive for easy processable high performance resins

A new tri-functional phthalonitrile monomer tris(3-(3,4-dicyanophenoxy)phenyl) phosphate (TPP) was first synthesized and characterized with the intent of increasing the cross-linking rate of phthalonitrile resins. By combining TTP and di-functional phthalonitrile with aromatic diamine easy-processable formulations (η < 200 mPa·s at 150 °C) were developed. Thermosets were derived from the formulations by curing at 330 and 375 °C. The polymers that were post-cured at 375 °C demonstrated Young's moduli up to 7.2 GPa — which is the highest value reported for phthalonitriles. Thermal stability of these materials was on the high level featured to phthalonitriles (Tg > 450 °C, T5% > 500 °C, TOS5% > 500 °C, Yc at 900 °C > 80%). TPP, the introduced monomer, can be used as a stiffness increasing additive with common di-functional phthalonitriles, and easy-processable formulations for cost-effective techniques of composites manufacturing.

Synthesis of Hydrophilic Polyamide Copolymers Based on Nylon 6 and Nylon 46

Hydrophilic polyamide copolymers were successfully synthesized based on Nylon 6 and Nylon 46. This study aims to synthesize hydrophilic polyamides with moisture regain ability comparable to that of cotton. Random copolymers of nylon 6 and nylon 46 did not exhibit moisture regain rates higher than 6 %. A limited introduction of trifunctional monomer, diethylenetriamine (TA) produced the polyamides with higher mechanical strengths but failed to enhance the moisture regain. The incorporation of poly(ethylene oxide) oligomer with amine end groups increased the moisture regain but resulted in poor hydro-thermal and mechanical strength. A synergic effect was observed for copolymers which contain both nylon 46 units and PEO oligomer in regards to moisture regain capacity. Furthermore, the poor hydro-thermal and mechanical strength of Nylon/PEO segmented polyamides were drastically improved by the introduction of diethylenetriamine (TA). This study demonstrated that the polyamide copolymers comprising both PEO oligomer and TA unit record tensile moduli over 3 GPa and moisture regain rates of 8–10 wt%.

Molecular branching as a simple approach to improving polymer electrolyte membranes

A series of branched, sulfonated, phenylated poly(phenylene)s were synthesized by introduction of varying molar ratios of trifunctional monomer into the polymerization mixture. The branched polymers, containing between 0.25 and 2.00 mol% molecular branching, were cast into membranes and comprehensively characterized as polymer electrolyte membranes. Comparison to a linear, unbranched polymer analogue showed universally improved membrane properties as a result of branching. Branched membranes possessed greater tensile strength in the dry state and minor reductions in elongation at break. In the wet state, branched membranes showed improvements in both tensile strength and elongation at break, up to 47 and 43%, respectively. Water sorption decreased with increasing branching content, from 119% water uptake and 145% dimensional swelling, to as low as 45 and 61%, respectively. Notable increases in both thermal and chemical stability were observed. When assessed electrochemically, these trends were further highlighted: ex-situ proton conductivity showed a stepwise increase in membrane performance with increasing degrees of branching, up to 212 mS cm−1 at 80 °C and 95% RH. Finally, in-situ characterizations of membranes integrated into hydrogen fuel cells showed state-of-the-art hydrocarbon membrane performance, comparing favorably to the archetypal Nafion 211 under H2/O2 at both 100% and 50% RH, and outperforming it by as much as 18% in maximum power density under H2/Air at 100% RH.

IPN structured UV-induced peelable adhesive tape prepared by isocyanate terminated urethane oligomer crosslinked acrylic copolymer and photo-crosslinkable trifunctional acrylic monomer

In this paper, a linear isocyanate terminated urethane oligomer, polyethylene glycol modified isophorone diisocyanate oligomer (PEG-IPDI), was prepared by the reaction of polyethylene glycol and isophorone diisocyanate. It is mixed as a cross-linking agent with an acrylic copolymer composed of 2-ethylhexyl acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate and acrylic acid to form a network pressure sensitive adhesive (PSA) through the reaction of isocyanate groups in PEG-IPDI with hydroxyl and carboxyl groups in acrylic copolymer chains. By blending this network PSA with a photo-initiator and a trifunctional acrylic monomer in a certain ratio, the UV-curable PSA was obtained. After uniformly coating it on the treated polyethylene terephthalate film, a UV-induced peelable PSA tape for a silicon wafer dicing process was prepared. The PSA network formed before UV irradiation was held together with another network produced by UV irradiation of the trifunctional acrylate monomer to give an interpenetrating network (IPN) structure. The results showed that this novel UV-curable PSA tape with IPN structure had strong peel strength before UV irradiation, and could meet the fixed requirements of silicon wafer cutting process. After UV curing, the peel strength was remarkably lowered due to the formation of IPN structure. Compared to those semi-IPN structured PSA tapes prepared with traditional multi-functional urethane acrylate oligomers, the adhesion performances of IPN structured UV peelable PSA tape prepared in this work were similar, but the remaining adhesive on the wafer after the release of the UV cured tape was greatly reduced.

Improvement of thermal stability of EPDM by radiation cross-linking for space applications

The investigation of radiation effects on ethylene–propylene–diene terpolymer (EPDM) loaded with trifunctional monomer (trimethylolpropane triacrylate, TMPTA) at three concentrations (0, 2.5 and 5 phr) was accomplished by isothermal and nonisothermal chemiluminescence spectroscopies, thermal analysis, mechanical testing and scanning electron microscopy. All these investigations indicate the contribution of monomer to the improvement of degradation strength and the possible extension of improved material over the space and nuclear ranges. The monomer loading of 2.5 phr and 50 kGy exposure dose is the optimal conditions for the improvement in thermal strength of polymer. The radiation effect is related to the cross-linking, but the contribution of radiolysis on the thermal stability at 100 kGy must not be discarded. The modified EPDM presents satisfactory functional features related to the material durability. The oxidative degradation and cross-linking, the main ways to high material performances, are the competitive processes through which EPDM is qualified for special operation purposes.

Optimization and characterization of high-viscosity ZrO2 ceramic nanocomposite resins for supportless stereolithography

UV-curable high-viscosity ZrO2 ceramic nanocomposite resins were prepared for use in supportless stereolithography 3D printing. To improve their dispersion stability and photo-curing properties, the mixing ratio of nano- and micro-particles of ZrO2 was optimized to 70:30 by volume, and the surfaces of the mixed particles were functionalized with acrylate groups through hydrolysis and condensation of a silane coupling agent (APTMS, 3-acryloxypropyl trimethoxysilane). APTMS-coated ZrO2 ceramic particles were dispersed in mixtures of di- and tri-functional acrylate monomers with non-reactive diluents, based on interpenetrating networks. Rheological, dispersion, and photo-curing characteristics of APTMS-coated ZrO2 ceramic nanocomposite resins with 50 vol% of ceramic particles and with a high viscosity of over 20,000 cps were investigated using a rheometer, relaxation NMR, stability analyzer and photo-differential scanning calorimeter. The green bodies of the 3D-printed objects with different cross-linking densities were sintered at 1450 °C, and the cross-linking degree of the photopolymers in the sintered 3D-printed objects was optimized by analysis of the volume shrinkage, surface morphology, and density. This work widens the possibility of ceramic composite materials for supportless 3D printing, enabling fabrication of customized zirconia dental implant restorations, as an alternative to computer-aided design and computer-aided manufacturing.

Computer Simulation of Anisotropic Polymeric Materials Using Polymerization-Induced Phase Separation under Combined Temperature and Concentration Gradients.

In this study, the self-condensation polymerization of a tri-functional monomer in a monomer-solvent mixture and the phase separation of the system were simultaneously modeled and simulated. Nonlinear Cahn–Hilliard and Flory–Huggins free energy theories incorporated with the kinetics of the polymerization reaction were utilized to develop the model. Linear temperature and concentration gradients singly and in combination were applied to the system. Eight cases which faced different ranges of initial concentration and/or temperature gradients in different directions, were studied. Various anisotropic structural morphologies were achieved. The numerical results were in good agreement with published data. The size analysis and structural characterization of the phase-separated system were also carried out using digital imaging software. The results showed that the phase separation occurred earlier in the section with a higher initial concentration and/or temperature, and, at a given time, the average equivalent diameter of the droplets <dave> was larger in this region. While smaller droplets formed later in the lower concentration/temperature regions, at the higher concentration/temperature side, the droplets went through phase separation longer, allowing them to reach the late stage of the phase separation where particles coarsened. In the intermediate stage of phase separation, <dave> was found proportional to , where was in the range between and for the cases studied and was consistent with published results.

Photoinitiated Copper(I) Catalyzed Azide-Alkyne Cycloaddition Reaction for Ion Conductive Networks.

The photoinitiated copper(I) catalyzed azide-alkyne cycloaddition (photo-CuAAC) is a 'click' reaction that enables spatially and temporally controlled polymerizations. The solvent-less photopolymerization of multi-functional azide and cationic alkyne monomers results in the rapid formation of a charged polymer network. Full conversion of these monomers is achieved within 30 minutes under mild, blue-light irradiation conditions (470 nm light at 30 mW/cm2). The modulus of the material is readily tuned by controlling the ratio of di- and tri-functional alkyne monomers. Facile exchange of the hydrophobic bistriflimide counterion for a hydroxide anion yields an ion conductive polymer network with photopatternable charged regions. The spatiotemporal nature of the ionic photo-CuAAC reaction coupled with the chemical stability and mechanical flexibility suggests this chemistry is a facile and novel approach for ion-containing material synthesis (e.g., alkaline fuel cells components).

Superhydrophobic Coatings Prepared by the in Situ Growth of Silicone Nanofilaments on Alkali-Activated Geopolymers Surface.

As a highly hydrophobic and good environmental durable material, silicone nanofilaments have shown great advantages in the construction of superhydrophobic coatings. However, the synthesis of these materials has always been limited to the application of trifunctional organosilane monomers under the action of acidic catalysts. For the first time, long-chain polymeric hydrogenated siloxane-poly(methyl-hydrosiloxane) (PMHS) was used to synthesize rapidly silicone nanofilaments in situ under alkaline conditions. A dense silicone nanofilament coating was obtained by PMHS + geopolymer layer on a smooth iron sheet, and achieved by one-step brushing of PMHS on the surface of a just-solidified alkali-activated metakaolin-based geopolymer coating at 120 °C for an hour of sealed curing. This composite coating was followed by a superhydrophobic composite coating with a contact angle of approximately 161° and a rolling angle of 2°. Consistent with this, laser scanning confocal microscopy and field-emission scanning electron microscopy images show the presence of micro- and nanoscale features that enable the entrapment of air when exposed to water and endow excellent superhydrophobic properties. Because geopolymer material has good adhesion ability with metal, ceramic, or other materials, the composite superhydrophobic coating is expected to be widely used.

Eugenol-based thermally stable thermosets by Alder-ene reaction: From synthesis to thermal degradation

Performing thermostable materials such as phenolic or epoxy networks are classically obtained from petrobased and harmful monomers. In this study, alternative solutions based on renewable eugenol trifunctional monomer (TEP) are proposed. Thus, innovative biobased Alder-ene thermosets are prepared by reacting TEP with two different bismaleimides: N,N′-1,3-phenylene bismaleimide (PhBMI) and polydimethylsiloxane bismaleimide (SiBMI) leading to different crosslinked aromatic networks. These materials exhibit various mechanical properties with very different Tg values of −113 °C and 247 °C for SiBMI and PhBMI materials respectively. However, both thermosets exhibit excellent thermal properties with elevated degradation temperature and high char yield. The degradation behavior was studied using thermogravimetric analysis – Fourier transformed infrared spectroscopy (TGA-FTIR): only silicon compounds were observed for SiBMI, whereas phosphorus and carbonaceous products had specific signatures in degradation gases for PhBMI. Kinetic analysis of degradation confirmed those different behaviors. Our contribution with two original Alder-ene thermosets is an innovative way to develop sustainable versatile high-performant materials.

Combination of Ethylene, 1,3-Butadiene, and Carbon Dioxide into Ester-Functionalized Polyethylenes via Palladium-Catalyzed Coupling and Insertion Polymerization

The combination of ethylene (E), 1,3-butadiene (BD), and carbon dioxide (CO2), three extensively utilized feedstocks, into a polymer via the copolymerization pathway is of great interest in both academia and industry. However, copolymerization for even two of them (E/BD, E/CO2, BD/CO2) is highly challenging; thus, copolymerization for three of them (E/BD/CO2) together is more elusive and remains unexplored. In this contribution, by employing a two-step strategy of palladium-catalyzed coupling and subsequent insertion polymerization, the E/BD/CO2 copolymerization via an allyl acrylate-type intermediate was achieved for the first time. The palladium-catalyzed [Pd(acac)2/PCy3] C–C coupling reaction of BD and CO2 followed by ring cleavage and esterification first generated the desired trifunctional monomer methyl-2-ethylidene-5-hydroxyhept-6-enoate acrylate (II). Subsequent palladium-catalyzed [(P^O)PdMedmso] coordination–insertion copolymerization of E and II afforded ester-functionalized polyethylenes inclu...

The effect of acrylate functionality on frontal polymerization velocity and temperature

ABSTRACTFrontal polymerization is a method of converting monomer(s) to polymer via a localized reaction zone that propagates from the coupling of thermal diffusion with the Arrhenius kinetics of an exothermic reaction. Several factors affect front velocity and temperature with the role of monomer functionality being of particular interest in this study. Polymerizing a di and triacrylate of equal molecular weight per acrylate revealed that as the proportion of triacrylate was increased the velocity and temperature increased. This is attributed to increased crosslinking and autoacceleration. Comparing several different acrylate monomers, both neat and diluted with dimethyl sulfoxide (DMSO) so as to maintain constant acrylate group concentration, shows that velocity increases with increased functionality from mono to difunctional monomers. This trend breaks when applied to tri‐ and tetraacrylates, with fronts containing trifunctional monomer being the fastest. Acrylates containing hydroxyl functionality, as in the case of pentaerythritol‐based triacrylates, are slower than acrylates without. This is attributed to a chain‐transfer event and was tested using octanol and a hydroxyl‐free acrylate. It has also been shown that small amounts of water cause a lowering of front velocity due to energy lost via vaporization, which lowers the front temperature. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 982–988