Triallyl Cyanurate Research Articles

Crosslinking of polyamide-6 initiated by proton beam irradiation

Initiation of crosslinking of polyamide-6 (PA6) by proton beam irradiation was investigated for a virgin material as well as for PA6 containing up to 5wt% of triallyl cyanurate (TAC) as a crosslinking coagent. The gel point was found to be 144 and 40kGy for virgin PA6 and for PA6 with 1wt% of TAC, while for higher TAC content gel content was determined to be around zero absorbed dose. The ratio between crosslinking and scission of macroradicals formed by irradiation was found to be around 0.65 regardless on presence or absence of TAC and its concentration. The more detailed discussion on chemical processes as well as on final structure formation after irradiation is based on data from differential scanning calorimetry, detecting a decrease of both lamellar thickness and crystalline portion, but an increase of glass transition temperature.

Influence of triallyl cyanurate as co-agent on gamma irradiation cured high density polyethylene/reclaimed tire rubber blend

Utilization of waste from tire industry as reclaimed tire rubber (RTR) by formation of blends with high density polyethylene (HDPE) is great area to be focused. Enhancement of properties by the addition of triallyl cyanurate (TAC) as a co-agent with 1%, 3% and 5% to blend of HDPE 50wt% and RTR 50wt% in presence of gamma irradiation curing were investigated. Specifically, mechanical and thermal properties were studied as a function of amount of TAC and gamma irradiation dose in range of 50–200 kGy. The resultant blends were evaluated for the values of impact strength, gel content, thermal stability, tensile properties, rheological properties and morphological properties with increasing irradiation dosage and TAC loading. The mechanical properties tensile strength, hardness, impact strength of blend containing 3% of TAC were substantially increased with increasing irradiation dosage up to 150 KGy. Rheological analysis has shown increase in viscosity with increase in TAC loading up to 3% and 150 KGy irradiation dosages. 3% loading of TAC lead to better set of properties with150 KGy gamma irradiation dosage.

Cure Characteristics of Foaming EVA Compounds: Influence of EVA Types and Cure Systems

Influence of poly(ethylene-co-vinyl acetate) (EVA) types and cure systems on cure characteristics of foaming EVA compounds were investigated. Three kind EVAs with different VA contents were employed. Influence of triallyl cyanurate (TAC) and dicumylperoxide (DCP) content on the cure characteristics were examined. The minimum torque (T min ) and delta torque (ΔT) decreased as the VA content increased. The ΔT was increased by adding TAC and by increasing the DCP content. For the foaming EVA compounds without TAC, the cure times such as the minimum cure time (t min ), scorch time (t₂), and optimal cure time (t ) did not show a specific trend according to the DCP contents. For the foaming EVA compounds containing TAC, the cure times decreased as the DCP content increased. From the experimental results, it was found that efficienct DCP/TAC ratio for improvement of the crosslink density was 1.1~2.0.

Crosslinked composite membrane by radiation grafting of 4-vinylpyridine/triallyl-cyanurate mixtures onto poly(ethylene-co-tetrafluoroethylene) and phosphoric acid doping

New crosslinked composite membranes containing doped phosphoric acid (PA) were prepared by radiation induced grafting of 4-vinylpyridine (4-VP) and triallyl cyanurate (TAC) mixtures at various concentrations onto poly(ethylene-co-tetrafluoroethylene) (ETFE) films followed by acid doping. The effect of grafting parameters such as TAC concentration, absorbed dose and monomer concentration on the degree of grafting was investigated. The properties of the obtained membranes such as chemical composition, thermal stability and mechanical properties were evaluated using Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA) and universal mechanical tester, respectively. The proton conductivity of the membranes was investigated in correlation with TAC content and temperature using the impedance spectroscopy. Of all samples, the crosslinked membrane obtained from grafting a mixture of 4-VP with 5 vol% TAC having a DG of 65% exhibited proton conductivity as high as 39 mS/cm under dry condition at 120 °C. The mechanical properties of the crosslinked membranes were significantly improved compared to the non-crosslinked counterpart. The presence of an interesting combination of properties in PA doped crosslinked membrane suggests a potential for application in medium temperature proton exchange membrane fuel cell.

Poly[(mercaptopropyl)methylsiloxane] (PMMS)-based antibacterial polymer coatings prepared by a two-step sequential thiol–ene click chemistry

Poly[(mercaptopropyl)methylsiloxane] (PMMS)-based antibacterial polymer coatings have been prepared through a two-step sequential thiol–ene click chemistry utilizing 1-allyl-3-decylimidazolium bromide (ADIm) as antibacterial monomer and triallyl cyanurate (TAC) as the crosslinker. These films with different content of ADIm were characterized by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and pencil hardness. It was found that the mechanical and thermal properties of these films were largely influenced by the content of ADIm in the films. Films with imidazolium bromide groups displayed excellent antimicrobial activity against Staphylococcus aureus with 100% killing efficiency.

Tensile, flexural and morphological properties of electron beam-crosslinked LDPE–EPDM blends

The effect of electron beam (EB) irradiation on the tensile, flexural and morphological properties of low-density polyethylene (LDPE)/ethylene-propylene diene elastomer (EPDM) blends had been studied in the absence and presence of crosslink promoters, such as trimethylolpropane triacrylate (TMPTA) and triallyl cyanurate (TAC). Blends were prepared by melt mixing of LDPE and EPDM followed by EB irradiation at various doses. The gel fraction (%) of irradiated blends was increased with an increase in EPDM content as well as EB irradiation dose and consequently the tensile and flexural properties of the blends increased. The incorporation of crosslinking promoters accelerated the gel formation and improved the properties upon irradiation more efficiently. The phase morphology of fractured surface displayed immiscibility with a rough appearance before irradiation. But after irradiation, the surface became fine, smooth and uniform, which went on increasing upon irradiation, supporting the steady increase in mechanical properties. Surface appeared even smoother in the presence of TMPTA and TAC.

The effect of multifunctional monomers/oligomers Additives on electron beam radiation crosslinking of poly (styrene-block-isoprene/butadiene-block-styrene) (SIBS)

Abstract The effect of multifunctional monomers or oligomers (MFM/O) additives on electron beam (E-beam) radiation induced crosslinking of poly (styrene- block -isoprene/butadiene- block -styrene) (SIBS) was studied. Ten types of MFM/O were investigated, including trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane triacrylate (TMPTA), triallyl cyanurate (TAC), polybutadiene diacrylate (PB-diacrylate), ethylene glycol dimethylacrylate (EGDMA), butylene glycol dimethacrylate (BGDMA), 1,2-polybutadiene. The effects of MFM/O concentration and E-beam radiation dose on properties of SIBS were studied including tensile strength, elongation-at-break, modulus, gel content, equilibrium swelling and crosslink density. TMPTA significantly improved the tensile modulus and crosslink density of SIBS. SIBS with TMPTMA and TMTPMA with inhibitor showed a 50% increase in tensile strength. The solubility of MFM/O in SIBS was also investigated by a selective swelling method. The MFM/O were found to be soluble in both phases of SIBS. The viscosity of SIBS with methacrylate type MFM/O was stable at 200 °C.

Heat resistant polymeric coatings based on triallylcyanurate

The possibility electro-copolymerization of triallyl cyanurate with vinyl acetate, acrylic acid, and 1-vinylimidazole in the presence of zinc chloride was considered. It was found that the complexed monomer was reduced at an electrode easier than free. On the basis of these monomers dense, uniform polymeric films were formed on the electrode surface.

The effect of electron-beam irradiation and halogen-free flame retardants on properties of poly butylene terephthalate

Abstract Engineering plastics like Poly (butylene terephthalate) due to their desirable properties have various industrial applications. Neat PBT is highly combustible, so it is necessary to improve significantly its fire retardancy to meet the fire safety requirements. The combustion performance of PBT can be improved by addition of appropriate flame retardant additives. In this study we have investigated the effect of halogen free flame retardants, i.e. melamine and aluminum phosphate, and instantaneously electron beam radiation-induced crosslinking in the presence of Triallyl cyanurate on various properties of PBT. The results of gel content showed that a dose range of 200–400 kGy leads to high cross linked structure in this polymer. Also mechanical experiments showed that its structure became rigid and fragile due to irradiation. Radiation crosslinking of this polymer made its dielectric loss coefficient ten times lower than non-irradiated polymer, but had no effect on its dielectric constant. Moreover the addition of the fire retardant additives as impurity decreased the dielectric loss coefficient. TGA analysis in nitrogen exhibited that irradiation increases char formation and use of the fire retardant additives leads to reduction of onset temperature and formation of higher char quantity than pure PBT. According to the results of UL-94, irradiated samples burned with lower speed and less dripping in vertical and horizontal positions than pure polymer. Finally irradiation of the polymers containing fire retardant additives with a dose of 400 kGy led to self-extinguishing and non-dripping and reach to V-0 level in the UL-94 V.

Proving Reliability and Reproducibility of the Technology for Grafting and Crosslinking Blends Based on Ethylene Vinyl Acetate Copolymer and Triallyl Cyanurate by Electron Beam Irradiation, Using Statistical Analysis of Experimental Data Obtained

Proving Reliability and Reproducibility of the Technology for Grafting and Crosslinking Blends Based on Ethylene Vinyl Acetate Copolymer and Triallyl Cyanurate by Electron Beam Irradiation, Using Statistical Analysis of Experimental Data Obtained

ROLE OF COAGENTS IN PEROXIDE VULCANIZATION OF NATURAL RUBBER

ABSTRACTThe drawbacks of peroxide vulcanization can largely be overcome by introducing suitable co-curing agents (coagents) in the formulation. The role of various coagents, such as zinc diacrylate (ZDA), trimethylolpropane trimethacrylate (TMPTMA), and triallyl cyanurate (TAC) in the peroxide vulcanization of natural rubber (NR) was studied by Fourier transform infrared spectroscopy. Cross-link density was measured by the equilibrium–swelling technique. Cross-linking mechanism of peroxide in NR was interpreted by comparing the spectra of cured and uncured vulcanizates. The predominance of hydrogen abstraction over the radical addition was established (at 160 °C). Coagent ZDA produces ionic as well as covalent cross-links in the vulcanizate. Ionic cross-links have the ability to slip along the hydrocarbon chains and thus resemble polysulfidic cross-links. Hence, ZDA can be chosen for applications where good mechanical properties are required. Coagent TMPTMA produces covalent cross-links between polymer chains and is suitable for high-modulus applications. TAC, although it bridges through covalent cross-links, is not a suitable coagent for highly unsaturated rubbers like NR.

Radiation vulcanization of natural rubber with polyfunctional monomers

This study presents the effect of the polyfunctional monomers (PFMs) triallylcyanurate (TAC), triallylisocyanurate (TAIC), trimethylolpropane trimethacrylate (TMPT), ethylene glycol dimethacrylate (EDMA) and zinc diacrylate (ZDA) on the mechanical properties of natural rubber (NR) crosslinked by electron beam (EB) processing. Dependence of mechanical properties and crosslink density on irradiation dose was determined from a dose range of 50 to 200 kGy. The control blends, obtained with benzoyl peroxide as curing agent, were prepared by blending on a laboratory roller and the control sample curing was accomplished on hydraulic press at 160 °C. The results showed an increase in mechanical properties and crosslink density due to the introduction of PFMs. Also, based on the comparison between EB irradiation and dibenzoyl peroxide vulcanization efficiency, the experimental results show that EB irradiation gave the best results.

Shrinkage studies in electron beam curable polyurethane pressure-sensitive adhesive

Polyurethane (PU)-based pressure-sensitive adhesive (PSA) has been manufactured by electron beam (e-beam) irradiation using urethane-acrylate. The effect of variation of e-beam dose and crosslinkers viz. triallyl cyanurate (TAC), triallyl isocyanurate, polymeric methylene diphenyl diisocyanate, carbodiimide-modified methylene diphenyl di-isocyanate, methylene diphenyl di-isocyanate, and isophorone di-isocyanate (IPDI) has been studied concerning the shrinkage, adhesion properties, and gel content of the PU-PSA. It was found that with increasing e-beam dose the shrinkage is increased up to 25 kGy, but remained constant thereafter with further increasing the dose up to 60 kGy. Similarly, with increasing concentration of crosslinkers from 2 to 6%, shrinkage is increased but beyond that there is no appreciable change. A comparative study of the effect of different crosslinkers on shrinkage, adhesion properties, and gel content of PU-PSA was carried out, and it was found that TAC leads to the maximum, while IPDI to the lowest shrinkage. However, the opposite was observed for the adhesion properties, i.e. the use of IPDI ensures the maximum and of TAC, the minimum adhesive performance characteristics.

Effects of electron-beam irradiation crosslinking on PA6 fibers

Irradiation crosslinking of PA6 fibers with and without the presence of triallyl cyanurate (TAC) was investigated. The dose for incipient gel formation was 500 kGy for pristine PA6 fibers and it decreased to 12 kGy when 5 % TAC was incorporated. Changes in structure and properties of irradiated PA6 fibers were analyzed by X-ray diffraction, infrared spectroscopy and thermal gravimetric analysis. Irradiation crosslinking improved the anti-dripping properties of PA6 fibers effectively. Irradiated samples showed an increase of the breaking strength and then a decrease at further doses due to radiolysis effect, the elongation at break decreased during the irradiation process. Irradiation crosslinking had not changed the crystal form and crystallinity decreased first and then increased to some extent. DSC measurement reported that the melting temperature decreased with increasing the dose. The thermal stability decreased after irradiation whereas the amount of nonvolatile residue at 600 °C increased as the irradiation dosage increased. The infrared spectra of irradiated samples were identical with the unirradiated, no new bands were observed.XPS analysis showed that the number of C-C band increased after irradiation which proves that branching and crosslinking has occurred.

Design of a super‐ductile polypropylene/polycarbonate blend with high heat resistance by using reactive plasticizer

AbstractHigh‐performance blend of polypropylene (PP) and polycarbonate (PC) has not been explored. The difficulty is caused by the big differences in melt viscosity (PP: low viscosity vs. PC: high viscosity) and polarity (PP: nonpolar vs. PC: polar). We put forth a new approach using a reactive plasticizer which is preferentially soluble with PC and polymerizable by organic peroxide. As the plasticizer, diallyl phthalate and triallyl cyanurate (TAC) were used. By reactive extrusion of PP/PC/plasticizer/dicumyl peroxide (e.g., 80/14/6/0.12 wt. ratio), reaction‐induced phase decomposition took place in the dispersed PC particles to develop a regularly phase‐separated nanostructure and the graft copolymer of PP and polymerized plasticizer was in situ generated at the interface. The extruded blend showed an excellent ductile behavior with about 500%‐elongation at break. TAC was very effective to elevate the heat resistance. Then, a super‐ductile PP/PC blend with high heat resistance was successfully developed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Method for Simultaneously Improving the Thermal Stability and Mechanical Properties of Poly(lactic acid): Effect of High-Energy Electrons on the Morphological, Mechanical, and Thermal Properties of PLA/MMT Nanocomposites

Nanocomposites derived from poly(lactic acid) (PLA) and organically modified montmorillonite (oMMT) have been cross-linked by high-energy electrons in the presence of triallyl cyanurate (TAC). The morphology of untreated and cross-linked PLA/MMT nanocomposites was characterized by wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM). This treatment can improve both the thermal stability and the glass-transition temperatures of the PLA nanocomposites (e.g., PLA-MMT-TAC 30kGy, 50kGy, and 70kGy) because of the formation of cross-linking structures in the nanocomposites that will considerably reduce the mobility of polymers. Interestingly, at relatively low irradiation doses (e.g., 30 and 50 kGy) a good balance between tensile strength and elongation at break for the PLA nanocomposites could be achieved. These mechanical properties are superior to those of pure PLA. Therefore, combining nanotechnology and electron beam cross-linking is a promising new method of simultaneously improving the mechanical properties (toughness and tensile strength) and thermal stability of PLA.

Thermo‐sensitive electrospun fibers prepared by a sequential thiol‐ene click chemistry approach

AbstractThis manuscript describes a straightforward method to prepare stimuli‐responsive fibers by the combined technology of electrospinning and two facile thiol‐ene click chemistry processes: photo‐initialized thiol‐ene radical addition and thiol‐Michael nucleophilic addition. By controlling the molar ratio of poly((3‐mercaptopropyl)methylsiloxane) (PMMS) and the cross‐linker, triallyl cyanurate, PMMS‐based fibers can be partially photo‐crosslinked via UV illumination during electrospinning, to grant them the solvent‐resistant property, meanwhile leaving unreacted free mercapto groups on the surfaces, which could be further functionalized with stimuli‐responsive polymer brushes. To demonstrate the feasibility of this approach, a facile thiol‐Michael addition protocol between PMMS fibers with free thiol groups on the surfaces and maleimide‐terminated PNIPAM has been developed, which allows for the preparation of polysiloxane fibers with thermo‐responsive PNIPAM brushes on the surfaces. PMMS‐g‐PNIPAM fibers show thermo‐sensitive behavior to the environment, having a hydrophilic surface at 20°C (water contact angle ∼28°) and a hydrophobic surface at 45°C (water contact angle ∼132°). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012.

Enhancement of flame retardancy and mechanical properties of HDPE/EPM based radiation shielding composites by electron beam irradiation

Radiation shielding materials based on polymer or its composites require higher material properties to endure the harsh radiation environments. In this investigation, electron beam (E-beam) irradiation and/or cross-linking agent triallyl cyanurate (TAC) were applied into the composites of a high density polyethylene (HDPE)/ethylene propylene monomer (EPM) blend containing B2O3 and/or PbO. The tensile strength increased as much as twice while the elongation enhanced more than 5times by irradiation of 150kGy with 10MeV E-beam. Further enhancement of the tensile and elongation properties was achieved by applying both 1wt.% TAC and E-beam irradiation, while use of 1wt.% TAC alone decreased the mechanical properties. Flame retardancy of the polymer composites by mean of limit oxygen index (LOI) also achieved to higher than 21 without using any flame retardant additive.

Effect of Gamma Irradiation Crosslinking on PA6 Fibers

Gamma irradiation crosslinking of nylon6 fibers with and without the presence of triallyl cyanurate(TAC) was studied, XRD、DSC、IR and TG were used to analyze the effects of irradiation crosslinking on structure and properties of PA6 fibers. The melt-drip performance of PA6 fibers was improved after irradiation crosslinking. The breaking strength increased first then decreased as a function of absorbed dose, while elongation at break decreased. The melting temperature and crystallinity decreased with increasing the dose. Besides, the onset temperature of degradation fell slightly and the amount of non-volatile residue at 600oC increased as the irradiation dosage increased.

Synthesis of Novel Hexathiolated Squalene and Its Thiol-Ene Photopolymerization with Unsaturated Monomers

In this work is described the synthesis of a multifunctional thiolated squalene. Thiol-ene coupling reactions were employed to functionalize the six double bonds of squalene, using thiolacetic acid. Hydrolysis of the resulting thioacetates, rendered the corresponding hexathiolated squalene SQ6SH. This compound was further photopolymerized separately with triallyl cyanurate, pentaerythritol triacrylate and diethyleneglycol divinyl ether. Real Time FTIR kinetics revealed that homopolymerization of the ene monomers took place in addition to the thiol-ene photopolymerization. Flexible films were obtained when SQ6SH was photopolymerized in bulk with the above mentioned unsaturated monomers.