67,095 research outputs found
Methyl Methacrylate Oligomerically-Modified Clay and its Poly (Methyl Methacrylate) Nanocomposites
A methyl methacrylate oligomerically-modified clay was used to prepare poly(methyl methacrylate) clay nanocomposites by melt blending and the effect of the clay loading level on the modified clay and corresponding nanocomposite was studied. These nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and cone calorimetry. The results show a mixed intercalated/delaminated morphology with good nanodispersion. The compatibility between the methylacrylate-subsituted clay and poly(methyl methacrylate) (PMMA) are greatly improved compared to other oligomerically-modified clays
ABA triblock copolymers: from controlled synthesis to controlled function
The ABA amphiphilic block copolymers, poly(hydroxyethyl methacrylate-hlock-methylphenylsilane-block-hydroxyethyl methacrylate) (PHEMA-PMPS-PHEMA) and poly[oligo(ethylene glycol) methyl ether methacrylate-block-methylphenylsilane-block-oligo(ethylene glycol). methyl ether methacrylate] (POEGMA-PMPS-POEGMA) were successfully synthesised via atom transfer radical polymerisation (ATRP). Macroinitiators suitable for the ATRP of oligo(ethylene glycol) methyl ether methacrylate and 2-hydroxyethyl methacrylate were synthesised from the condensation reaction of alpha,omega-dihalopolymethylphenylsilane and 2'-hydroxyethyl 2-bromo-2-methylpropanoate. The copolymers were characterised using H-1 NMR and C-13 NMR spectroscopy and molecular weight characteristics were determined using size exclusion chromatography and H-1 NMR. The aggregation behaviour of some of the copolymers in water was studied using transmission and scanning electron microscopy and dynamic light scattering. These revealed the prevalent aggregate species to be micelles. Larger aggregates of 300-1000 nm diameter were also observed. The UV induced degradation of the aggregates was studied by UV-Vis spectroscopy. The thermal behaviour of selected copolymers was studied by differential scanning calorimetry and microphase separation of the two components was demonstrated
Polymerisable surfactants for polymethacrylates using catalytic chain transfer polymerisation (CCTP) combined with sulfur free-RAFT in emulsion polymerisation
Statistical copolymers of methacrylic acid and methyl methacrylate were synthesised via free radical catalytic chain transfer polymerisation (CCTP) in emulsion to form a hydrophilic emulsifier/surfactant. The vinyl-terminated oligomers were in turn utilised as chain transfer agents, with no further purification, for the formation of diblock copolymers with butyl and methyl methacrylate which constitutes the emulsifier via sulfur-free reversible additionâfragmentation chain transfer polymerisation (SF-RAFT). In turn these polymers were solubilized with various concentrations of ammonium hydroxide and utilised in the surfactant-free emulsion polymerization of butyl methacrylate using persulfate initiators, which also stabilized the polymer particles with observed no coagulation, with solid contents as high as 40%
Sequence distribution studies of dichloroprotoanemonin-methyl methacrylate copolymers
Chloride elimination and ultraviolet bands in dichloroprotoanemonin/methyl methacrylate copolymer
A Strategy for the Design of Flame Retardants: Cross-linking Processes
Cross-linking is identified as an effective means for flame retardation of polymers and schemes for the cross-linking of poly(ethylene terephthalate) and poly(methyl methacrylate) are presented. For poly(ethylene terephthalate) the scheme involves polymerization of the initially produced vinyl ester. This is followed by chain-stripping, producing a polyene, and cyclization of this polyene. For poly(methyl methacrylate) the scheme entails the formation of anhydride linkages between adjacent polymer strands. Evidence is presented to show the efficacy of these processes and information is produced to aid in the identification of new flame retardants
Prarancangan Pabrik Metil Metakrilat dari Aseton Sianohidrin Kapasitas 63.000 Ton/Tahun
Methyl methacrylate is a chemical in the industry are derived from ester derivative and one form of acrylic resin monomer. Methyl methacrylate is widely used in the industries of paint, resin, household appliances, cosmetics, and polymers. Needs methyl methacrylate in Indonesian is still imported from abroad (imports) and tended to increase each year. Therefore, the establishment of methyl methacrylate plant in Indonesian is very important to reduce imports. Factory methyl methacrylate is expected to meet domestic demand and the possibility to be exported.
The process manufacture of methyl methacrylate by the hydrolysis reaction of acetone cyanohydrin and sulfuric acid into metakrilamid sulfate. Then metakrilamid sulfate esterification with methanol to produce methyl methacrylate with byproduct ammonium bisulfate. Both of these processes is reacted in the continuous flow stirred tank reactor (CSTR) and reacted in the liquid phase conditions. The hydrolysis reaction is set at a temperature of 130ÂșC and a pressure of 1 atm, while the esterification reaction is set at a temperature of 150ÂșC and a pressure of 7 atm. Methyl methacrylate product purification using distillation and decantation process, so that the resulting product with a purity of 99.8%.
Factory methyl methacrylate is designed with a capacity of 63,000 tons/year in operation for 330 days/year. The factory employed about 160 workers, require raw materials acetone cyanohydrin as much as 61,177.32 tons/year, as much sulfuric acid 67,073.05 tons/year, and methanol as much as 21,645.35 tons/year. Unit utility as supporting the production process requires as much water 47,779.68 kg/hour supplied from the Bengawan Solo river, saturated steam as much as 51,599,901.73 kJ/hour supplied from fuel boiler with fuel oil as much as 640.49 liters/hour, needs 750 kW electric power is supplied from PLN and generator set as a backup, and the compressed air requirement of 91.37.m3/hour.
Based on economic analysis, methyl methacrylate plant requires a fixed capital of Rp. 768,667,006,796.33 and working capital of Rp.522,362,960,248.84. Profits earned before tax of Rp. 532,161,308,204.95 annually. Profits after tax of Rp. 334,193,727,030.00 annually. The results of the feasibility analysis states that the percent return on investment (ROI) before tax amounted to 62.11% and after tax of 43.48%. Pay out time (POT) before taxes of 1.4 years, while after tax of 1.9 years. Break even point (BEP) amounted to 58.61% of capacity, and shut down point (SDP) amounted to 31.89% of capacity. Discounted cash flow (DCF) of 38.06%. Based on the analysis with these parameters, so the factory methyl methacrylate can be declared eligible to set up in Indonesian
TGA/FTIR: An Extremely Useful Technique for Studying Polymer Degradation
Thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, TGA/FTIR, has been used to probe the degradation of several polymeric systems. These include poly(methyl methacrylate) in the presence of various additives, graft copolymers of acrylonitrile-butadiene-styrene and styrene-butadiene with sodium methacrylate and styrene with acrylonitrile, blends of styrene-butadiene block copolymers with poly(vinylphosphonic acid) and poly(vinylsulfonic acid), and cross-linked polystyrenes. Additives may interact with poly(methyl methacrylate) by coordination to the carbonyl oxygen to a Lewis acid and the subsequent transfer of an electron from the polymer chain to the metal atom or by the formation of a radical which can trap the degrading radicals before they can undergo further degradation. When an inorganic char-former is graft copolymerized onto a polymer, there is a good correlation between TGA behavior in an inert atmosphere and thermal stability in air, but this is not true when the char is largely carbonific
A library of thermoresponsive PEG-based methacrylate homopolymers: How do the molar mass and number of ethylene glycol groups affect the cloud point?
In this study, a novel library of thermoresponsive homopolymers based on poly (ethylene glycol) (EG) (m)ethyl ether methacrylate monomers is presented. Twentyâseven EG based homopolymers were synthesized and three parameters, the molar mass (MM), the number of the ethylene glycol groups in the monomer, and the chemistry of the functional side group were varied to investigate how these affect their thermoresponsive behavior. The targeted MMs of these polymers are varied from 2560, 5000, 8200 to 12,000âgâmolâ1. Seven PEGâbased monomers were investigated: ethylene glycol methyl ether methacrylate (MEGMA), ethylene glycol ethyl ether methacrylate (EEGMA), di(ethylene glycol) methyl ether methacrylate (DEGMA), tri(ethylene glycol) methyl ether methacrylate (TEGMA), tri(ethylene glycol) ethyl ether methacrylate (TEGEMA), penta(ethylene glycol) methyl ether methacrylate (PEGMA), nona(ethylene glycol) methyl ether methacrylate (NEGMA). Homopolymers of 2â(dimethylamino) ethyl methacrylate (DMAEMA) were also synthesized for comparison. The cloud points of these homopolymers were tested in different solvents and it was observed that it decreases as the number of EG group was decreased or the MM increased. Interestingly, the end functional group (methoxy or ethoxy) of the side group has an effect as well and is even more dominant than the number of EG groups
Relationship between enhanced positronium formation and enhanced positron trapping in polymers at low temperature
Positron annihilation lifetime spectroscopy is used for investigation of low-density polyethylene and ethylene-methyl methacrylate copolymers of 1.45, 3.0, and 5.4 mole% of methyl methacrylate. The lifetime spectra are
collected at 30 K, one by one, as a function of elapsed time. In the computer analysis a new theoretical model is de eloped, which enables separating the annihilation from positron free state, its trapped state and bound state in
positronium. The positron trapping rate Âč and the enhanced positronium formation rate · are determined. The calculated values of Âč and · turned out to be linearly correlated. This correlation presumably originates from
an in°uence of trapped electrons on the trapping of positrons. The dependences of · on measurement time are determined for low-density polyethylene and ethylene-methyl methacrylate of different methyl methacrylate content. A theoretical model describing quantitatively the dependences is proposed.
The model considers the processes of electron{ion recombination, electron trapping, and electron scavenging by dipolar carbonyl groups supplied by methyl methacrylate additives
Understanding the role of MAM molecular weight in the production of PMMA/MAM nanocellular polymers
Nanostructured polymer blends with CO2-philic domains can be used to produce nanocellular materials with controlled nucleation. It is well known that this nanostructuration can be induced by the addition of a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM) to a poly(methyl methacrylate) (PMMA) matrix. However, the effect of the block copolymer molecular weight on the production of nanocellular materials is still unknown. In this work, this effect is analysed by using three types of MAM triblock copolymers with different molecular weights, and a fixed blend ratio of 90âŻwt% PMMA and 10âŻwt% of MAM. Blends were produced by extrusion. As a result of the extrusion process, a non-equilibrium nanostructuration takes place in the blends, and the micelle density increases as MAM molecular weight increases. Micelle formation is proposed to occur as result of two mechanisms: dispersion, controlled by the extrusion parameters and the relative viscosities of the polymers, and self-assembly of MAM molecules in the dispersed domains. On the other hand, in the nanocellular materials produced with these blends, cell size decreases from 200 to 120âŻnm as MAM molecular weight increases. Cell growth is suggested to be controlled by the intermicelle distance and limited by the cell wall thickness. Furthermore, a theoretical explanation of the mechanisms underlying the limited expansion of PMMA/MAM systems is proposed and discussed
- âŠ