Trifunctional Monomer Research Articles

Corrosion Protection of Tinplated Steel by Silica-Methacrylate Hybrid Coatings via Sol–Gel Process

In this work we present the development of two organic–inorganic hybrid coatings with interpenetrating network for corrosion protection of tinplated steel. The hybrid coatings were obtained from the hydrolytic condensation of tetraethoxysilane and 3-methacryloxypropyltrimethoxysilane, which has a free-radical polymerizable C˭C double bond. The tri-functional monomers, triallyl isocyanurate and trimethylolpropane triacrylate (TMPTMA) with three C˭C double bonds, were used to develop a highly cross-linked organic network attached to the inorganic moieties through covalent Si–C bonds, respectively. Both were characterized by Fourier transformed infrared spectroscopy and thermogravimetric analysis. The corrosion resistance performance was evaluated by potentiodynamic polarization, electrochemical impedance spectroscopy, and salt spray test. The results indicated that the Sol-TMPTMA hybrid coating exhibited excellent anti-corrosion ability by forming a physical barrier between tinplated steel substrate and its external environment.

Highly stretchable thermoset fibers and nonwovens using thiol-ene photopolymerization.

In this report, we describe the preparation and characterization of a new class of thermoset fibers with high elongation and elastic recovery. Integrating UV-activated thiol-ene photopolymerization and electrospinning, we demonstrate an environmentally friendly single step approach to convert small monomeric precursor molecules into highly elastic fibers and nonwoven mats. The fibers were derived by in situ photopolymerization of a trifunctional vinyl ether monomer and a tetrafunctional thiol. Although thermosets often offer good chemical and thermal stability, these fibers also have a high average elongation at break of 62%. The elastomeric nature of these vinyl-ether based fibers can be partly attributed to their subambient Tg and partly to the cross-link density, monomer structure, and resulting network homogeneity. Nonwoven mats of these fibers were also stretchable and exhibited a much higher elongation at break of about 85%. These thermoset stretchable fibers could have potential applications as textile, biomedical, hot chemical filtration, and composite materials.

Curing behaviour and mechanical properties of pigmented UV-curable epoxy acrylate coatings

Purpose – The purpose of this work was to study the effect of chemical structure of reactive diluents on the curing behaviour and physical–mechanical properties of a titanium dioxide pigmented UV-curable epoxy acrylate system. Design/methodology/approach – Two different tri-functional and two different tetra-functional acrylate monomers were used as reactive diluents in the formulations. The curing behaviour of the formulations was studied by using photo-differential scanning calorimetry analysis. The rate of curing, conversion at the maximum rate and ultimate conversion for different formulations were calculated. In addition, the physical and mechanical characteristics of the cured films, including glass transition temperature and modulus, were measured by using a dynamic mechanical analysis technique. Findings – The results showed that the ultimate conversion for non-pigmented pentaerythritol triacrylate (PETA) and trimethylol propane triacrylate (TMPTA) formulations were almost similar, but the interference effect of titanium dioxide particles on the curing of the PETA formulations was found to be more considerable in comparison to the TMPTA formulations. The extent of reaction for tetra-functional acrylate monomers was considerably less than those for tri-functional acrylate monomers. The Tg and storage modulus of non-pigmented PETA, TMPTA and pentaerythritol tetraacrylate (PE4TA) formulations were almost the same and higher than that for ditrimethylol propane tetraacrylate (DiTMP4TA) formulations. However, Tg and storage modulus of pigmented tetra-functional acrylate monomer formulations were higher than those for tri-acrylate monomer formulations. Research limitations/implications – The curing conditions (temperature and UV intensity) can affect the network formation and consequently will affect on the properties of the cured films. Practical implications – The pigmented UV-curable coatings are interested for many industries such as wood and automotive industries. The reported data can be used by the formulators working in the R&D departments. In addition, the results obtained can be used by the researchers who are active in the field of structure–property relationship for UV-curable coatings. Social implications – UV-curing systems are considered as one of the most environment-friendly coatings system. Therefore, the developing of its knowledge can help to extend its usage to different applications. Originality/value – The photopolymerisation of pigmented coatings is a great challenge and is hardly investigated in the literature. Therefore, in this research, the effect of chemical structure and functionality of different multifunctional acrylate monomers on the curing behaviour of pigmented formulations was investigated.

TBCPMA: a new trifunctional acrylic monomer for convenient synthesis of a well-defined amphiphilic graft copolymer by successive RDRP

A series of well-defined amphiphilic graft copolymers, consisting of a hydrophobic poly(tert-butyl acrylate) backbone and hydrophilic poly(N-isopropylacrylamide) side chains, were synthesized by successive reversible addition–fragmentation chain transfer (RAFT) polymerization and supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) in the presence of Cu(0). A new Cl-containing acrylate monomer, tert-butyl 2-((2-chloropropanoyloxy)methyl)acrylate, was first RAFT homopolymerized in a controlled way to give a well-defined homopolymer with a narrow molecular weight distribution (Mw/Mn = 1.10). This homopolymer directly initiated SARA ATRP of N-isopropylacrylamide to afford well-defined poly(tert-butyl acrylate)-g-poly(N-isopropylacrylamide) (PtBA-g-PNIPAM) graft copolymers (Mw/Mn ≤ 1.30) via the grafting—from a strategy without polymeric functionality transformation to introduce the initiating group. Finally, the hydrophobic PtBA backbone was selectively hydrolyzed in an acidic environment without affecting PNIPAM side chains to provide poly(acrylic acid)-g-poly(N-isopropylacrylamide) (PAA-g-PNIPAM) graft copolymers. The influences of the length of PNIPAM side chains and the salinity on the critical micelle concentration of the PtBA-g-PNIPAM amphiphilic graft copolymer were examined by fluorescence spectroscopy. Furthermore, thermo-responsive behaviors of the copolymers were investigated by UV-vis spectroscopy, dynamic light scattering, and transmission electron microscopy.

Properties of Polystyrene/Acrylic Acid Membranes After Sulphonation Reactions

Sulphonation reaction in styrenic membranes is a common method used to graft ionic groups needed to enhance proton conductivity in polymeric electrolytes (PEM). A synthesized copolymer of styrene and acrylic acid (94/6 % mol) was partially crosslinked using a trifunctional monomer, trimethylolpropane trimethacrylate (TMPTMA) (0.01% mol), like a crosslinking agent. The obtained material was subjected to different sulphonation reactions in order to prepare several PEM membranes. The sulphonation reactions used sulphuric acid (H2SO4, 98%) at 50, 75 and 100 %molar ratio considering amount of styrene rings, during 1 and 2 hours of reaction time. Fouriertransformed infrared spectroscopy (FTIR) spectra were obtained to identify specific chemical groups in these materials. Thermogravimetric analysis (TGA) and Dynamic Mechanical Analysis (DMA) were used to evaluate the thermal stability and mechanical effects after sulphonation reactions. Water absorption and its effect on proton conductivity by means of Electrochemical Impedance Spectroscopy (EIS) were also evaluated. FTIR spectra show characteristic bands corresponding to sulphone groups within macromolecular structure. Sulphonating agent concentration and/or sulphonation time induce higher glass transition temperatures and no changes in thermal stability when comparing with the no sulphonated material. Latter condition also allows higher water absorption and an enhancement in proton conductivity.

Preparation and Characterization of High-Melt-Strength Polylactide with Long-Chain Branched Structure through γ-Radiation-Induced Chemical Reactions

An easy procedure was applied to prepare high-melt-strength polylactide (PLA) that involves γ-radiation-induced free-radical reactions to introduce a long-chain branched structure onto a linear PLA precursor with addition of a trifunctional monomer, trimethylolpropane triacrylate (TMPTA). The results from size-exclusion chromatography coupled with multiangle laser light scattering (SEC-MALLS) detection indicate that the resultant long-chain branched PLA (LCB PLA) samples have an increased molecular mass and an elevated branching degree with increasing amount of TMPTA incorporated during the irradiation process. Various rheological plots including viscosity, storage modulus, loss tangent, Cole–Cole plots, and weighted relaxation spectra were used to distinguish the improved melt strength for LCB PLA samples. The effect of LCB structure on elongational rheological properties was further investigated. The LCB PLA samples exhibited an enhancement of strain-hardening under elongational flow. The enhanced melt ...

Morphology Analysis for Effect of the Polymer Cluster Produced from Adamantyl-bearing Trifunctional Monomer on the Stability of Liquid Crystal Alignment

Abstract Effect on stability of liquid crystal (LC) alignment due to formation of polymer clusters on alignment films produced from the copolymer of 1,3,5-triacryloyloxyadamantane and 4,4′-diacryloyloxybiphenyl was investigated with morphology analysis. Experimental results revealed that the stability of the LC alignment was increased because the polymer clusters effectively held the LC molecules adjacent to the polymer clusters.

Mussel-inspired hyperbranched poly(amino ester) polymer as strong wet tissue adhesive

Current medical adhesives based on cyanoacrylates typically exhibit cellular toxicity. In contrast, fibrin adhesives are non-toxic but have poor adhesive properties. To overcome these drawbacks we designed a simple and scalable adhesive precursor inspired by marine mussel adhesion that functioned with strong adhesion in wet conditions and with low cytotoxicity. Dopamine, an-amine derivative of an amino acid abundantly present in mussel adhesive proteins, was co-polymerised with a tri-functional vinyl monomer, to form a hyperbranched poly(β-amino ester) polymer termed poly(dopamine-co-acrylate) (PDA). A variety of molecular weights and crosslinking methods were analysed using an ex vivo porcine skin model and an almost 4 fold increase in wet adhesion strength was observed compared to TISSEEL® fibrin sealant. With a fast curing time, degradable properties and low cytotoxicity, PDA is highly attractive for medical purposes and could have a broad impact on surgeries where surgical tissue adhesives, sealants, and haemostatic agents are used.

Molecularly Imprinted Polymer Microspheres Containing Photoswitchable Spiropyran-Based Binding Sites

A versatile approach for the preparation of photoswitchable molecularly imprinted polymers (MIPs) is proposed where the selective recognition and the photoresponsive function are assumed by two different monomers. As a proof of concept, MIP microspheres were synthesized by precipitation polymerization for recognizing terbutylazine, a triazine-type herbicide. Formation of the selective binding sites was based upon H-bonding interactions between the template and the functional monomer methacrylic acid, whereas a polymerizable spiropyran unit was incorporated into the polymer matrix to provide light-controllable characteristics. A trifunctional monomer, trimethylolpropane trimethacrylate, was used as a cross-linker. The imprinted particles exhibited considerable morphological differences compared to their nonimprinted counterparts as observed by scanning electron microscopy. The imprinting effect was confirmed by equilibrium rebinding studies. The photoresponsiveness of the polymer particles was visualized by fluorescence microscopy and further characterized by spectroscopy. The template binding behavior could be regulated by alternating UV and visible light illumination when analyte release and uptake was observed, respectively. Binding isotherms fitted by the Freundlich model revealed the photomodulation of the number of binding sites and their average affinity. This facile synthetic approach may give an attractive starting point to endow currently existing highly selective MIPs with photoswitchable properties, thereby extending the scope of spiropyran-based photoresponsive smart materials.

Use of a TrI-functional Crosslinking Agent in Styrene/Acrylic Acid Copolymers to Enhance Mechanical Properties for use as Membranes in Fuel Cells

Alternative copolymers to the well-known Nafion membranes are the styrene/acrylic acid PS/AA) copolymers, which have advantages in cost and availability of raw materials. Previous attempts to improve their mechanical properties involved crosslinking with divinyl benzene, but in this case the use of the tri-functional monomer TMPTMA (trimethylol propane trimethacrylate) is examined. Copolymers with a PS/AA molar ratio of 94/6 were prepared by a free radical polymerization reaction, including TMPTMA at 0.1, 0.01 and 0.001 % mol concentrations. Reactions were followed by percentage yield (gravimetry), Infrared spectroscopy (FTIR) and extent of crosslinking by gel percentage evaluation (soxhlet extraction) with three different solvents (water, tetrahydrofuran and dichloromethane). Thermal transitions were followed by calorimetry (DSC), stability by thermogravimetry (TGA) and mechanical properties by dynamic mechanical analysis (DMA). FTIR spectra show typical bands from the copolymer while the corresponding bands associated with crosslinking are overlapped; however, gel percentage evaluations show a higher level of crosslinking for the 0.1% TMPTMA copolymer and lack of solubility in water. DSC thermograms indicate an increment in the glass transition (Tg) and TGA exhibits a small increment in thermal stability for the crosslinked copolymers. Elastic moduli suggests a rubbery material for TMPTMA crosslinked copolymers while loss modulus confirms a Tg enhancement as observed by DSC. A 0.1 % TMPTMA copolymer does not form a membrane due to its insolubility and infusibility.

Molecularly imprinted polymers for corticosteroids: impact of polymer format on recognition behaviour

A comparative study was performed on different polymeric formats for targeting corticosteroids, focusing on the use of bulk monolith and precipitation polymerisation strategies. Hydrocortisone-17-butyrate was selected as the template and methacrylic acid as the functional monomer, following 1H NMR investigation of the pre-polymerisation mixture. Three different cross-linkers were tested, ranging from moderate to highly hydrophobic. The synthesised bulk and precipitated imprinted polymers were physically characterised by nitrogen sorption and evaluated by means of HPLC and frontal chromatography against a range of template analogues. While some degree of selectivity for the template was achieved for all tested polymers, the ones based on the tri-functional cross-linking monomer trimethylolpropane trimethacrylate exhibited the longest retention for all corticosteroids, especially in the precipitated format, which suggested broader group selectivity.

Synthesis of novel hyperbranched polymers featuring oxazoline linear units and their application in fast‐drying solvent‐borne coating formulations

ABSTRACTNovel acid‐terminated hyperbranched polymers (HBPs) containing adipic acid and oxazoline monomers derived from oleic and linoleic acid have been synthesized via a bulk polymerization procedure. Branching was achieved as a consequence of an acid‐catalyzed opening of the oxazoline ring to produce a trifunctional monomer in situ which delivered branching levels of >45% as determined by 1H and 13C NMR spectroscopy. The HBPs were soluble in common solvents, such as CHCl3, acetone, tetrahydrofuran, dimethylformamide, and dimethyl sulfoxide and were further functionalized by addition of citronellol to afford white‐spirit soluble materials that could be used in coating formulations. During end group modification, a reduction in branching levels of the HBPs (down to 12–24%) was observed, predominantly on account of oxazoline ring reformation and trans‐esterification processes under the reaction conditions used. In comparison to commercial alkyd resin paint coatings, formulations of the citronellol‐functionalized hyperbranched materials blended with a commercial alkyd resin exhibited dramatic decreases of the blend viscosity when the HBP content was increased. The curing characteristics of the HBP/alkyd blend formulations were studied by dynamic mechanical analysis which revealed that the new coatings cured more quickly and produced tougher materials than otherwise identical coatings prepared from only the commercial alkyd resins. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3964–3974

Optical properties and UV-curing behaviors of optically clear PSA-TiO2 nano-composites

Optically clear PSAs-TiO2 nano-composites were investigated for the purpose of display. TiO2 nano-particles can be directly incorporated into the polymer matrix to form high refractive index PSAs-nanocomposites films. Moreover, this study also employed semi-interpenetrated structured polymer network through the process of UV-curing with high refractive trifunctional acrylic monomer. The optical properties of PSAs-TiO2 nano-composites were examined by using UV-visible spectroscopy and a prism coupler. Viscoelastic properties were obtained by ARES and adhesion performance was measured by the peel strength, probe tack and shear adhesion failure temperature. Furthermore, curing behaviors of the PSAs-TiO2 nano-composites were investigated by using FTIR-ATR and gel content.

A highly branched polythiourethane acrylate used for UV-curable high antireflection coatings

A series of highly branched polythiourethane acrylates (BPTUAs) were prepared through the double thiol-ene click reaction of thiol-endcapped difunctional thiourethane as an oligomer A2 (Oligo-TU) with trimethylolpropane tri(thioglycolate ethylene glycol acrylate) (TMPTTA) as a trifunctional monomer B3 in different ratios. The Oligo-TU was synthesized via the addition reactions of 2,4-toulene diisocyanate with 1,4-butanediol, and further with 4,4′-thiobisbenzenethiol. The TMPTTA was synthesized by the thiol-ene click reaction of trimethylolpropane tri(thioglycolate) (TMPTT) with an excess of ethylene glycol diacrylate. For comparison, a tetrafunctional thiourethane acrylate (TUA) was also synthesized. Finally, the obtained BPTUA and TUA were further modified with 2-mercaptobenzothiazole, 2-mercaptothiazoline and mercapto-5-methyl-thiadiazole, respectively, to form highly branched polyfunctional thiazole-based acrylates BPTUA-TAs and TUA-TAs. The molecular structures were confirmed by FT-IR and 1H NMR analyses. The number average molecular weights and their polydispersity were determined by GPC spectroscopy. The UV irradiation using a medium pressure mercury lamp was applied to prepare the optical films in the presence of a photoinitiator. The refractive indices of UV-cured films were measured using a He-Ne laser at 632.8nm. The results showed that both BPTUA and TUA films possess the similar refractive indices in the range of 1.592–1.604. However, the higher refractive indices in the range of 1.603–1.620 with BPTUA-TA films than 1.601–1.609 of TUA-TA films were obtained. All samples showed the high pencil hardness and impact resistance, as well good flexibility.

The role of PB-1 on the long chain branching of PP by electron beam irradiation in solid state and melt viscoelastic behavior

In this study, a long-chain branched polypropylene (LCB PP) was prepared by electron beam irradiation in the presence of polybutene-1 (PB-1) and a trifunctional monomer, trimethylolpropane trimethacrylate (TMPTMA). The effect of PB-1 on branching is evaluated by measuring the viscoelastic behavior in shear and extensional mode of deformation. Long-chain branched structure showed prominent higher zero-shear viscosity (η0) and storage modulus (G′), longer relaxation time and pronounced strain-hardening behaviors. It is found that 10wt% of PB-1 resin in PP matrix increase the efficiency of branching process which can be due to the effect of PB-1 resin in facilitating the mobility of macro-radicals generated during irradiation. At higher percentages, due to the high tendency of PB-1 resin to β-scission, the degradation reaction is more pronounced than its mobilizing effect in branching process.

Thermoreversible nonlinear diels‐alder polymerization of furan/plant oil monomers

AbstractNovel trifunctional monomers based on renewable resources were prepared and subsequently polymerized via the Diels‐Alder (DA) polycondensation between furan and maleimide complementary moieties. Three basic approaches were considered for these nonlinear DA polycondensations, namely the use of (i) a bisfuran monomer in combination with a trismaleimide (A2 + B3 system) and (ii) a trisfuran monomer in conjunction with a bismaleimide (A3 + B2 system) leading to branched or crosslinked materials, and (iii) the use of monomers incorporating both furan and maleimide end groups (A2B or AB2 systems), which lead to hyperbranched structures. The application of the retro‐DA reaction to the ensuing polymers confirmed their thermoreversible character. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Preparation and characterization of dual curable adhesives containing epoxy and acrylate functionalities

Bisphenol A type methacrylate, glycidyl methacrylate, acrylic acid and a trifunctional monomer were cured using both ultraviolet (UV) and thermal methods. The UV and thermal curing behavior of these components was evaluated using photo-differential scanning calorimetry (Photo-DSC) and Fourier Transform infrared spectroscopy (FT-IR) analyses, as well as gel fraction and pendulum hardness measurements. The reaction rate was fast, and an increasing amount of CC double bond character was observed by FT-IR, demonstrating an effective reaction in the presence of both UV irradiation and heat. The gel fraction analysis also confirmed the formation of crosslinks in the structure after the curing process. The pendulum hardness test revealed the nature of the curing process at different UV doses after UV and thermal curing. The adhesion strength was also evaluated as a function of epoxy group concentration, demonstrating that adhesion increased with increasing epoxy group content. The thermal degradation characteristics were monitored by thermal gravimetric analysis (TGA). The bonding between the epoxy and carboxyl groups resulted in a delayed degradation of the cured adhesive.

UV硬化型インキの組成が及ぼす各種基材への接着特性(第1報)

UV硬化型インキの組成が及ぼす各種基材への接着特性(第1報)

TBHBMA: a novel trifunctional acrylic monomer for the convenient synthesis of PAA-g-PCL well-defined amphiphilic graft copolymer

A series of well-defined amphiphilic graft copolymers, consisting of a hydrophilic poly(acrylic acid) (PAA) backbone and hydrophobic poly(ε-caprolactone) (PCL) side chains, was synthesized by the combination of reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening polymerization (ROP). A new acrylate monomer containing a ROP initiation group, tert-butyl(2-((4-hydroxybutanoyloxy)methyl)acrylate), was first prepared using tert-butyl acrylate as the starting material, and it was homopolymerized by RAFT in a controlled way to give a well-defined homopolymer bearing ROP initiation group in every repeating unit. This homopolymer directly initiated ROP of ε-caprolactone to provide well-defined poly(tert-butyl acrylate)-g-poly(ε-caprolactone) graft copolymers via the grafting-from strategy without post-polymerization functionality transformation. Finally, the hydrophobic poly(tert-butyl acrylate) backbone was selectively hydrolyzed in an acidic environment without affecting the PCL side chains to afford poly(acrylic acid)-g-poly(ε-caprolactone) amphiphilic graft copolymers possessing the hydrophilic PAA backbone and equally distributed hydrophobic PCL side chains. The self-assembly behavior of the obtained amphiphilic graft copolymers and pH-sensitivity of the resultant micelles were investigated by fluorescence spectroscopy, DLS, and TEM. DSC and XRD analysis showed the crystallization behavior of poly(acrylic acid)-g-poly(ε-caprolactone) graft copolymers.

アダマンチル基を有する三官能モノマーを用いた高分子クラスター形成による液晶配向安定化

アダマンチル基を有する三官能モノマーを用いた高分子クラスター形成による液晶配向安定化