Trimethylol Melamine Research Articles

Trisurfactantomethylol melamines: Synthesis, structural characterization and physicochemical properties of aqueous systems

Trimethylol melamine (TMM) trifunctional core was prepared to synthesize TSMM (Trisurfactantomethylol melamine) with cationic (CTAB {Hexadecyltrimethylammonium bromide}, CPC {Hexadecylpyridinium chloride}) and nonionic (polysorbate-40 and 60) surfactants as branching material. Melamine (Me), Formaldehyde (F), Surfactant (S) in 1:3:3 ratios were used for TSMMs synthesis via condensation reaction through nucleophilic addition. TSMMs were characterized with FTIR, FT-NMR, FT-RAMAN, and TGA to depict -CH2-CH- covalent bond formation between methylol of TMM and α-C of surfactants on releasing H2O molecule. The 1001 cm−1 stretching frequency with CTAB and CPC both, and 996, 992 cm−1 stretching frequencies with polysorbates-40 and 60 for Me-NH-CH2–CH-S bond are supported by 1023 cm−1 Raman frequency and 16–27% weight loss on TGA from 190 to 405 °C. TCTMM (TriCTABmethylol melamine), TCPMM (TriCPCmethylol melamine), TP4MM (Tripolysorbate-40methylol melamine) and TP6MM (Tripolysorbate-60methylol melamine), a series of TSMMs varied with an alkyl chain (AC) of C-15 to 17 with variable head groups to attain adequate hydrophobicity and hydrophilicity. Thereby, their hydrophobic and hydrophilic interactions in aqueous solutions at 298.15 K have illustrated the structural activities of their head groups and AC with their physicochemical properties. Structural constituents of TSMMs with adequate tentropy on account of their several localized electronic sites have acted as interacting coordinates for encapsulating/conjugating activities to explore a host and guest chemistry.

A trimethylol melamine functionalized polyvinyl alcohol network for high performance nano-silicon anodes

Cross-linking between TMM and PVA chains contributes to good mechanics of the binder and high Li diffusion coefficient, thus a Si anode with high rate capability and excellent cycling stability is obtained.

Reverse mapping method for complex polymer systems.

We present a comprehensive approach for reverse mapping of complex polymer systems in which the connectivity is created by the simulation of chemical reactions at the coarse-grained scale. Within the work, we use a recently developed generic adaptive reverse mapping procedure that we adapt to handle the varying connectivity structure resulting from the chemical reactions. The method is independent of the coarse-grained and fine-grained force-fields by design and relies only on a single control parameter. We employ the approach to reverse map four different systems: a three-component epoxy network, a trimethylol melamine network, a hyperbranched polymer, and a polyethylene terephthalate. In the case of the epoxy network, we use two fine-scale representations: fully atomistic and united-atom. Whereas the trimethylol melamine network the hyperbranched polymer and the polyethylene terephthalate are reverse mapped to the fully atomistic description. After the reverse mapping, we examine the fine-grained structure by comparing the radial distribution functions with respect to the control parameter. Moreover, in the case of the epoxy we perform tensile-test experiments and examine the resulting Young's modulus. In all cases, we show how the properties of the reverse mapped systems depend on the control parameters. In general, we see that the results are relatively insensitive to the control parameter and the resulting atomistic systems are stable. Only for the trimethylol melamine network, we notice chemically incorrect conformations when the reverse mapping is performed too fast. We provide a remedy for this issue. © 2017 Wiley Periodicals, Inc.

PROCESS OPTIMIZATION OF ECO-FRIENDLY FLAME RETARDANT FINISH FOR COTTON FABRIC: A RESPONSE SURFACE METHODOLOGY APPROACH

The [Formula: see text]-methylol dimethyl phosphono propionamide (MDPA) flame retardant compounds are predominantly used for cotton fabric treatments with trimethylol melamine (TMM) to obtain better crosslinking and enhanced flame retardant properties. Nevertheless, such treatments are associated with a toxic issue of cancer-causing formaldehyde release. An eco-friendly finishing was used to get formaldehyde-free fixation of flame retardant to the cotton fabric. Citric acid as a crosslinking agent along with the sodium hypophosphite as a catalyst in the treatment was utilized. The process parameters of the treatment were enhanced for optimized flame retardant properties, in addition, low mechanical loss to the fabric by response surface methodology using Box–Behnken statistical design experiment methodology was achieved. The effects of concentrations on the fabric’s properties (flame retardancy and mechanical properties) were evaluated. The regression equations for the prediction of concentrations and mechanical properties of the fabric were also obtained for the eco-friendly treatment. The R-squared values of all the responses were above 0.95 for the reagents used, indicating the degree of relationship between the predicted values by the Box–Behnken design and the actual experimental results. It was also found that the concentration parameters (crosslinking reagents and catalysts) in the treatment formulation have a prime role in the overall performance of flame retardant cotton fabrics.

Degradation Kinetics of Organophosphorus Flame Retardant from Cotton Fabric

The organophosphorus compound N-methylol dimethyl phosphonopropionamide (MDPA) is extensively used for durable flame retardant (FR) treatments for cotton fabrics. For optimum finishing treatment, MDPA is used with the Trimethylol melamine (TMM) or dimethylol dihydroxyethylene urea (DMDHEU) for cotton fabric treatments. The amino resins TMM known to pose severe toxic problems such as; breathing problems, headache and most importantly, cancer. In the production, consumption and eventually in the disposal phase of FR with TMM treated cotton fabrics, the release of TMM and toxic emissions cannot be ignored. In this study, mineralization and degradation of the organophosphorus FR compound from the cotton fabric using Advanced Oxidation Process (AOP) was successfully employed. The kinetics of degradation of FR substance from the cotton fabric was studied. The rate of degradation of the FR substance from the cotton fabrics was observed with chemical oxygen demand (COD). The kinetic rate constant equations and characterization of the mineralization and degradation of the FR substance by the AOP reaction was developed with the COD values. The organophosphorus FR on the fabric found to follow the first-order of kinetics of degradation from the cotton fabric.

Carboxymethyl cellulose reinforced poly(vinyl alcohol) with trimethylol melamine as a chemical crosslinker

ABSTRACTIn this investigation, carboxymethyl cellulose (CMC)‐reinforced poly(vinyl alcohol) (PVA) were prepared with trimethylol melamine as a chemical crosslinker. The structure and property of hydrogels were measured by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), texture analysis, and rheometry. The FTIR spectra demonstrated that the etherification reaction successfully occurred in the PVA–CMC hydrogels, and the SEM figures exhibited the homogeneous porous structure of the CMC–PVA hydrogels. The compression strength of the PVA–CMC hydrogels was 15 times higher than that of the PVA hydrogels. Moreover, the PVA–CMC hydrogels exhibited a higher storage modulus than that of the PVA hydrogels; this illustrated better elasticity for the PVA–CMC hydrogels. As a result, CMC‐modified PVA hydrogels with high mechanical behavior will broaden the potential applications of hydrogels, such as in wound dressings, facial masks, and skin‐protection layers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44590.

Generic Adaptive Resolution Method for Reverse Mapping of Polymers from Coarse-Grained to Atomistic Descriptions.

In this paper, we propose a new generic approach for reverse mapping from coarse-grained to atomistic scale based on the adaptive resolution scheme (AdResS). In AdResS simulation, two spatial domains, modeled at two different scales, are brought together in a concurrent simulation by defining a hybrid region where particles can switch representation from one model to another. We use AdResS as a central part of a reverse mapping algorithm from a different perspective by treating the whole simulation box as a hybrid region and changing the resolution as a function of time during the course of a molecular dynamics simulation. The proposed method depends only on a single parameter that controls the reverse mapping process and it is independent of atomistic and coarse-grained force-fields. We performed a reverse mapping of three different systems, simple molecules (dodecane), polymer chains (polyethylene) and ring molecules (trimethylol melamine) with a degree of coarse-graining ranging from two to ten heavy atoms. The conformational and dynamical properties of the reconstructed systems are in excellent agreement with the reference atomistic simulation.

Trifunctional cross‐linker trimethylol melamine enhancing adhesive force of PVA hydrogels

ABSTRACTAdhesive force is a critical feature in vitro for soft hydrogels as wound dressing. Here we employ trimethylol melamine as a tri‐functional cross‐linker to enhance the adhesive force of poly(vinyl alcohol) (PVA) hydrogels. First, trimethylol melamine was prepared using melamine and formaldehyde by a condensation reaction. Then PVA was cross‐linked in an aqueous medium to form hydrogels by using trimethylol melamine as a cross‐linker. It was found that trimethylol melamine cross‐linked PVA hydrogels (TMCPVA) exhibited a good adhesion property with a low degree of cross‐linking and no residue after the TMCPVA peeled from skins, indicating the TMCPVA were suitable for adhesive wound dressing. Moreover, their structures, morphology and adhesive forces were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and texture analyzer (TA). The results indicated that TMCPVA would be promising wound dressing materials with biocompatible and well‐adhesive properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43774.

Optimizing Organophosphorus Fire Resistant Finish for Cotton Fabric Using Box-Behnken Design

N-methylol dimethyl phosphonopropionamide (MDPA) is one of the most utilized fire resistant (FR) finishes for cotton fabrics, utilized as part of a formulation with trimethylol melamine (TMM) to acquire better crosslinking and enhanced FR properties. The system parameters of the finishing treatment were upgraded for better FR properties and low mechanical loss to the fabric by the response surface methodology utilizing Box-Behnken statistical designed experimental strategy. The impacts of concentration on the cotton fabric's properties (fire resistance and mechanical properties) were assessed with the regression equations. The optimum conditions by predicting the FR reagents focusing intact mechanical properties of the fabric were additionally studied. It was found that the parameters of crosslinking agents in the FR formulation have a prime role in the general FR properties of the cotton fabrics. The R-squared estimations of the considerable number of responses were above 92%, demonstrating the level of relationship between the predicted values by the Box-Behnken frameworks and the real test results.

In situ degradation of organophosphorus flame retardant on cellulosic fabric using advanced oxidation process: A study on degradation and characterization

N-methylol dimethyl phosphonopropionamide (MDPA) is one of the most effective organophosphorus flame retardants for cellulosic fabrics, used in combination with Trimethylol melamine (TMM) to obtain durable and improved flame retardant properties. While their use is responsible for severe health problems, there is a need today to study methods to eliminate or degrade the durable flame retardant products which stay on discarded flame retardant textiles. The final aim is to improve the reusability of discarded textiles and to increase their energetic yield during the incineration phase. In this work, the degradation and mineralization of the flame retardant MDPA on cellulosic fabric, was studied using an advanced oxidation process (AOP) based on Fenton reaction. The effect of varying concentrations of Fenton's reagents (H2O2 and Fe2+ in aqueous medium) on the degradation of the MDPA was studied. The degradation of MDPA in aqueous media was monitored by measuring chemical oxygen demand (COD) of the reaction mixture over time. The mechanical properties of the cellulosic fabric after Fenton's reaction were unaltered in both warp and weft directions. The flammability test and thermogravimetric (TGA and DTG) results confirmed the degradation of MDPA flame retardant from the fabric. Pyrolysis combustion flow calorimeter (PCFC) confirms that there is a higher heat release after Fenton's reaction degradation which makes the degraded flame retardant cotton interesting for energy production by incineration.

Preparation and Characterization of Microencapsulated n-octadecane as Phase Change Materials

In this paper, a kind of microcapsule containing phase change material of n-octadecane was successfully synthesized based on in situ polymerization where trimethylol melamine and hexamethylol melamine were shell materials. We used difierent emulsiflcation time, reaction time and difierent treatment to improve the quality of the microcapsules. The microcapsule and coated fabric were characterized by the optical microscope, Scanning Electronic Microscope (SEM), laser diameter distribution machine and Difierential Scanning Calorimeter (DSC). The optical microscope and SEM pictures showed that this microcapsule has good surface conflguration. Particle size with laser diameter distribution machine displayed that grains of the microcapsule were distributed evenly. The DSC results revealed the phasechanging temperature and enthalpy of the microcapsule.

MgO-templated nitrogen-containing carbons derived from different organic compounds for capacitor electrodes

Carbons containing nitrogen (C–N composites) were derived from three commercial organic compounds, poly(vinylpyrrolidone) (PVP), polyacrylamide (PAA), and trimethylolmelamine (TMM) using the MgO template method. The C–N composites formed in nitrogen at 700–1000 °C had nitrogen content, W N, of 3–23 mass% and the specific surface area by N 2 adsorption, S BET, of 60–2000 m 2 g −1 without activation. Generally high nitrogen content of the starting compound led to larger W N, but W N was not proportional to the N/C mole ratio in the compounds. The value of S BET strongly depended on the compound: S BET (PVP) > S BET (PAA) ≫ S BET (TMM). There was a tendency for W N to decrease with increasing S BET. The capacitance measured in 1 mol dm −3 H 2SO 4 by cyclic voltammetry, C M in F g −1, suggested that both W N and S BET are influential in gaining large C M. For the composites with W N > 5 mass%, the capacitance normalized by S BET, C A = C M/ S BET, was 0.17–0.65 F m −2, which was larger than the electric double layer capacitance (0.05–0.15 F m −2), indicating that the pseudo-capacitance contributes significantly to C M. The value of C A increased with increasing W N, but a correlation between C A and particular nitrogen species on the surface measured by XPS was obscure. It was suggested that the large C A is not simply explained by redox reactions of the surface functional groups. The composite derived from PAA at 900 °C showed 234 F g −1 at 2 mV s −1 and 181 F g −1 at 100 mV s −1 with acceptable yield of the composite.

The bonding of a hydroxy-functional organophosphorus oligomer to nylon fabric using the formaldehyde derivatives of urea and melamine as the bonding agents

In this research, we studied the mechanism of bonding a hydroxy-functional organophosphorus oligomer (HFPO) to nylon 6.6 fabric using the formaldehyde derivatives of urea and melamine, including dimethyloldihydroxyethyleneurea (DMDHEU) and trimethylolmelamine (TMM), as the bonding agents. The nylon fabric treated with HFPO/DMDHEU or HFPO/TMM retained significant amount of phosphorus after multiple launderings. The laundering durability of the HFPO applied to nylon was probably attributed to the formation of a crosslinked polymeric network on the nylon fiber. The nylon fabric treated with HFPO/DMDHEU showed higher percent phosphorus retention than that treated with HFPO/TMM. The percent phosphorus retention of the treated nylon increased as the DMDHEU or TMM concentration was increased, and the nylon fabric's stiffness follows the same trend. The micro-scale combustion calorimetry and thermal analysis data indicate that the HFPO bound to nylon reduced peak heat release rate and heat release capacity of the nylon fabric, decreased decomposition temperature and promoted the char formation of the treated fabric. The nylon/cotton blend military fabric treated with HFPO/DMDHEO or HFPO/TMM demonstrated flame retardant performance after 10 laundering cycles.

Enhancing the Antibacterial Properties of Cotton Fabric

Attempts were made to enhance the antibacterial properties of the cotton fabrics via pre-crosslinking with trimethylol melamine followed by subsequent treatment with iodine ( NH and NI) solution to create new active sites. The treated fabric shows the ability to inhibit as well as to arrest the growth of both of the bacillus subtilis and Escherichia coli. The antibacterial activity is determined by the degree of modification, the extent of iodine retention, as well as the ease of iodine liberation. Repeated laundering—recharging cycle could fully bring back the antibacterial functions of the finished cotton fabrics.

Comparison of different reactive organophosphorus flame retardant agents for cotton. Part II: Fabric flame resistant performance and physical properties

N-Methylol dimethylphosphonopropionamide (MDPA) is one of the most commonly used durable flame retardant agents for cotton. In our previous research, we developed a new flame retardant finishing system based on a hydroxy-functional organophosphorus oligomer (HFPO) and bonding agents, such as dimethyloldihydroxyethyleneurea (DMDHEU) and trimethylolmelamine (TMM). In this research, we compared the flame resistant performance as well as physical properties of the cotton fabric treated with these two flame retardant finishing systems. The cotton fabric treated with MDPA/TMM has a higher initial limiting oxygen index (LOI) than that of the fabric treated with HFPO/TMM due to higher nitrogen content in the system. The LOI of the cotton fabric treated with the HFPO and MDPA systems becomes identical when the treated fabric contains equal amount of phosphorus and nitrogen. The MDPA/TMM shows higher laundering durability on cotton than HFPO/TMM system. The fabric treated with HFPO/TMM and MDPA/TMM has low wrinkle resistance and low strength loss whereas the fabric stiffness significantly increases when the TMM concentration is increased.

Comparison of different reactive organophosphorus flame retardant agents for cotton: Part I. The bonding of the flame retardant agents to cotton

N-Methylol dimethylphosphonopropionamide (MDPA), known as “Pyrovatex CP” and “Pyrovatex CP New” commercially, has been one of the most commonly used durable flame retardant agents for cotton for many years. In our previous research, we developed a flame retardant finishing system for cotton based on a hydroxy-functional organophosphorus oligomer (HFPO) in combination with a bonding agent such as trimethylolmelamine (TMM) and dimethyloldihydroxyethyleneurea (DMDHEU). In this research, we investigated the bonding of these two flame retardant finishing agents to cotton. We found that the majority of MDPA is bound to cotton by its N-methylol group and that the use of TMM as a co-reactant modestly increases the fixation of MDPA onto cotton. For HFPO, however, the use of a bonding agent is necessary to form a covalent linkage between HFPO and cotton. Both the fixation of HFPO on cotton and its laundering durability are influenced by the effectiveness and concentration of the bonding agent. The commercial product of HFPO contains approximately 33% more phosphorus than that of MDPA and the percent fixation of HFPO on cotton is also moderately higher than that of MDPA. The bonding between MDPA and cotton is significantly more resistant to hydrolysis during multiple launderings than that between HFPO and cotton. The selection of catalyst also plays a significant role in influencing the bonding of the flame retardant agents to cotton.

NLO polymers based on cellulose diacetate and a cationic chromophore

An attempt has been made to prepare second-order nonlinear optic (NLO) materials based on cellulose diacetate and melamine derivatives. The NLO cationic chromophore, composed of 1,3-dimethyl-2-(4′-N,N-dimethylaminophenyl)-azo-imidazole chloride and small amounts of 1,3-dimethyl-2-(4′-N,N-dimethylaminophenyl)-azo-imidazole methylsulfate, was incorporated into a crosslink network formed from the reaction of cellulose diacetate with trimethylol melamine or hexamethylol melamine. The poled and cured NLO materials exhibited an electro-optic coefficient (r 13) of 1.03 or 1.42 pm/V, respectively, at the laser wavelength 1550 nm and a modulation frequency of 12.7 kHz; the r 13 values decreased to 97% or 86.6%, respectively, of the initial values after 4 days. The laser transmission loss was 0.58 or 0.6 dB, respectively. The crosslinked materials showed better temporal stability than the material of the host/guest system with a doped cationic chromophore. The results of Fourier transform infrared spectroscopy, dielectric relaxation and thermogravimetry analyses proved the formation of a crosslink structure, and the degree of dielectric relaxation was shown to became higher if a crosslinker of too high functionality was used.

Durable flame retardant finishing of the nylon/cotton blend fabric using a hydroxyl-functional organophosphorus oligomer

Cotton/nylon blends have been commonly used as the material for protective clothing, but those blend fabrics are not flame retardant finished because of the unavailability of effective flame retardant finishing systems. Previously, we investigated the use of a hydroxyl-functional flame retardant organophosphorus oligomer (FR) in combination with the mixture of dimethyloldihydroxyethyleneurea (DMDHEU) and trimethylolmelamine (TMM) as the binders for flame retardant finishing of cotton. In this study, we investigated the application of FR to the 50/50 cotton/nylon fabric. When the FR/DMDHEU/TMM system is applied to the fabrics of nylon-6,6 and nylon-6, approximately 40% of the FR applied is permanently bound to the nylon fabrics. FR is bound to the nylon fabrics mainly through the formation of a FR/TMM crosslinked polymeric network, thus becoming durable to multiple launderings. The cotton/nylon blend treated with FR shows high levels of flame retardant performance and excellent laundering durability. The treated fabric passes the vertical flammability test even after 50 home laundering cycles. The fabric stiffness as a result of the finishing process is still an obstacle to be overcome for practical use of this finishing system.

The combination of a hydroxy-functional organophosphorus oligomer and melamine-formaldehyde as a flame retarding finishing system for cotton

In previous research, it was found that melamine-formaldehyde resin can be used as a binder for a hydroxy-functional organophosphorus flame retarding agent (FR) on cotton. The role that trimethylol melamine (TMM) plays in this flame retarding system was studied. When TMM is applied to cotton, it forms crosslinks between cellulose molecules. When TMM is applied to cotton in the presence of FR, it reacts with FR to form a crosslinked polymeric network in addition to reacting with cotton. The formation of the crosslinked network improves the laundering durability of FR and also increases the fabric stiffness. The number of crosslinks among cotton cellulose formed by TMM decreases as the FR concentration in the system is increased. TMM also functions as a nitrogen provider to enhance the flame retarding performance of FR due to phosphorus-nitrogen synergism. Therefore, the amount of TMM used in a FR/TMM formula plays the most critical role in determining the effectiveness of this flame retarding system. The finish bath pH also plays a significant role in influencing the performance of the flame retarding system on cotton. The optimum pH was found to be around 4.

Microencapsulation of higher hydrocarbon phase change materials by in situ polymerization

Three higher hydrocarbon phase change materials (PCMs) with melting points of 25, 40 and 50°C were microencapsulated by in situ polymerization of amino-aldehyde resins. Trimethylolmelamine (TMM) and hexamethoxymethylolmelamine (HMMM) were studied as amino-aldehyde pre-polymers for microcapsule wall formation, in combination with emulsifying/modifying agents based on styrene-malein anhydride copolymers (SMA) of different molecular weights and different styrene-maleic acid anhydride ratios. Microcapsule sizes, size distribution and wall permeability were analysed. A mathematical model was developed for comparing the mechanical resistance of different batches of microcapsules, produced at different TMM-SMA ratios. Larger microcapsules with thicker walls and larger pores (MLAR) expressed lower resistance to breakage than slightly smaller microcapsules with thinner walls and finer pore structure (MSMA). Mathematical data were confirmed by a smudging colouration test. Laboratory microencapsulation process parameters were optimized to obtain impermeable microcapsules with improved mechanical stability. The process was transferred into a 10 l pilot reactor for two PCMs with melting points of 25 and 40°C. Dry powder of microencapsulated PCMs was obtained by spray drying of aqueous microcapsule suspensions.