The grafting of methyl methacrylate onto cotton by tri-n-butylborane

Methyl Methacrylate was grafted onto cotton by tri-n-butylborane in the presence of water. No graft was obtained in organic solvents, i.e., in the absence of water. The percentage of grafting increased with increases in reaction time, cotton amount, and initiator concentration. Pretreatment of cotton with pyridine also enhanced the percentage of grafting. Glycidyl methacrylate and ethyl acrylate were grafted onto cotton by tri-n-butylborane, while no grafting occurred when vinyl acetate and 4-vinyl pyridine were used. Usual radical initiators, such as azobisisobutyronitrile and benzoyl peroxide/dimethyl-p-toluidine, were not effective under the same conditions.     

Polymerization of methyl methacrylate in the presence of graphite

The polymerization of methyl methacrylate was carried out in the presence of graphite powder in water medium containing sulfur dioxide. The polymerization was initiated by a redox reaction between ash in graphite and HSO₃^?. Graphite powder encapusulated with polymethyl methacrylate was obtained in high yield. The mechanism of the polymerization and the capusulation are discussed.     

Grafting of methyl methacrylate onto silk fibers initiated by tri-n-butylborane

Structural characteristics of the methyl methacrylate (MMA)-grafted silk fibers using tri-n-butylborane as an initiator were analyzed by infrared spectroscopy and differential scanning calorimetry (DSC), and their refractive index and tensile properties were measured. Graft polymerization was promoted by FeCl₃ pretreatment of the silk. The graft yield reached a maximum by the immersion in 4% FeCl₃ solution for 1 min at 25°C. The infrared spectrum of poly(MMA)-grafted silk fibers showed overlapped absorption bands of silk fibroin with the β structure and of the grafted MMA polymer. A grafted silk fiber with graft yield of more than 140% exhibited two endothermic peaks at 321°C and 396°C on the DSC curve, attributed to the thermal decomposition of silk fibroin and grafted poly(MMA) chain, respectively. Refractive index measurements suggested that the molecular orientation and the crystallinity of the silk fiber decreased with increasing graft yield. Electron photomicrographs showed that silk was coated by grafted PMMA. The tensile strength of the grafted silk decreased rapidly by the grafting even at a lower level.     

Polymerization of methyl methacrylate by metallocenes

Attempts at polymerizing methacrylate using metallocenes are reported. Polymerization is successful using ferrocene in a ketone solution, but not in benzene or without a solvent. Ketones are effective in the order: methyl ethyl ketone < cyclohexanone < cycloheptanone. Carbon tetrachloride has an accelerative effect on the polymerization in benzene and methyl ethyl ketone solutions, but no effect in cyclohexanone solution. Some binary systems, which consist of ferrocene and higher valence compounds such as cobalt trisacetylacetonate, are effective redox initiators. Cobaltocene polymerizes methyl methacrylate in the presence of carbon tetrachloride; zirconocene dichloride induces polymerization of methyl methacrylate in a cyclohexanone solution; whereas neither nickelocene nor titanocene dichloride are effective. Styrene and acrylonitrile were not polymerized by the metallocenes examined.     

Polymerization of caprolactam in the presence of acid esters of phosphoric acid

Conclusions Experimental data are given which indicate that the cationic initiation of caprolactam, which is initiated by acid esters of H₃PO₄ with lower alcohols, is analogous to the reaction in the presence of hydrogen halide acids, and not to that in the presence of acidic polyethylene glycol phosphates.The catalytic activity of the low-molecular-weight phosphates decreases with increase in the size of the alcoholic radical.Translated from Khimicheskie Volokna, No. 2, pp. 27–29, March–April, 1984.     

Polymerization of methyl methacrylate and acrylonitrile in the presence of copper BIAN complex

A novel type of copper-based regulating agents was first applied in radical polymerization of methyl methacrylate and acrylonitrile. It was shown that systems based on copper complex with redox-active bis(acetonaphthene) ligand (dpp-BIAN?CuCl)₂, carbon tetrachloride and different activating agents such as ascorbic acid or amines (tert-butylamine, diethylamine, triethylamine and pyridine) were capable to initiate polymerization of the above monomers in wide temperature range from 25 to 110 °C. The amine structure and basicity were found to make great impact on polymerization and molecular weight parameters of the obtained products. The systems developed are capable of conducting polymerization up to high monomer conversions in a wide temperature range leading to polymers with rather low molecular weight and moderate polydispersity. The most efficient system in terms of controlling the molecular weight characteristics of poly(methyl methacrylate) among others is the system based on (dpp-BIAN?CuCl)₂ and diethylamine, which makes it possible to obtain polymer with a polydispersity index of 1.36–1.60. In case of acrylonitrile polymerization, the highest polymer yield is achieved using a copper complex and triethylamine. The results of MALDI TOF mass spectroscopy measurements showed the presence of chlorine atoms at the chain ends of macromolecules. The formation of “living” chains during polymerization of methyl methacrylate was confirmed by the synthesis of block-copolymers with styrene.     

Polymerization of methyl methacrylate initiated by the redox system Mn3+/thioglycollic acid

The kinetics of aqueous polymerization of methyl methacrylate initiated by the redox system Mn³⁺–thioglycollic acid was studied in sulfuric acid in the temperature range of 35–50°C, and the rates of polymerization R_p and Mn³⁺ disappearance, etc., were measured. The effect of certain water-miscible organic solvents, neutral electrolytes, and complexing agents on the rates of polymerization has been investigated. A mechanism involving the formation of a complex between Mn³⁺ and thioglycollic acid whose decomposition yields the initiating free radical with the polymerization being terminated by the metal ion has been suggested.     

Polymerization of methyl methacrylate by copper-chelate of polyacrylic hydrazide

Copper-chelate of polyacrylic hydrazide was prepared, and its structure and properties were investigated. It was found that the chelate-polymer initiates radical polymerization of methyl methacrylate in aqueous dioxane at room temperature. The rate of polymerization initiated by the chelate-polymer was much higher than that by monomeric model-chelate of such as acethydrazide. The catalytic activity found in the copper-chelate of polyacrylic hydrazide is perhaps caused by the polyelectrolyte-behaviour of the polymer. The influences of the concentration of copper ion, molecular weight of polymer-ligand, ionic strength, hydrogen ion concentration and composition of solvent on the polymerization were investigated. It was considered that the polymerization is affected not only by stability but also by conformation of the chelate-polymer. The tacticity of the polymethyl methacrylate obtained is also discussed.     

Reaction catalyzed by montmorillonite: Polymerization of methyl methacrylate

The polymerization of methyl methacrylate (MMA) was carried out in aqueous media having various concentrations of potassium persulfate as initiator in the presence or the absence of montmorillonite (Texas) at various temperatures. The rate of polymerization increased with increasing initiator concentration. Thermal stabilities of the resulting composite materials were studied and the activation energies of polymerization and degradation were determined. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 367–372, 1997     

Polymerization of methyl methacrylate in the presence of molecular oxygen — a kinetic study

Methyl methacrylate was polymerized in aqueous medium initiated by a copper(II)-ascorbic acidoxygen system at 40°C and a kinetic study of the reaction is presented. The rate of polymerization, R_p showed an increase, constancy and then a decrease with increase in the [Cu²⁺]. The order with respect to [Cu²⁺] was 0.5 in the rate increase region. The order in monomer concentration changed gradually from 1.0 to 2.0 with increase in [Cu²⁺]. R_p became independent of ascorbic acid (AA) concentration and oxygen concentration at high concentrations. These results indicate that termination by mutual interaction of chain radicals predominates at low [Cu²⁺] while termination was exclusively by metal ions at high [Cu²⁺]. R_p was also observed to increase with temperature and ionic strength and to K_p/K_t^1/2 value was calculated and compared with literature values. Chain lengths were determined by viscometry for the polymers obtained under various experimental conditions.     

Polymerization of methyl methacrylate in water in presence of some egyptian sands and quartz pegmatite

The polymerization of methyl methacrylate was carried out in water in presence of some Egyptian sands and quartz pegmatite using sodium bisulphite as initiator. The polymerization was performed at 30, 40, 50 and 60°C using initiator concentrations varying from 0.05 to 0.3 mol/l. The overall rates of polymerization increased from 2.0 × 10^?5 mol/l·s to 4.8 × 10^?5 mol/l·s in presence of quartz pegmatite, to 5 × 10^?5 mol/l·s when Natron sand was used and to 6.4 × 10^?5 mol/l·s in the presence of Ahram sand, as the concentration of each was varied from 0 to 30 g/l. The effect of change of temperature, initiator and monomer concentration on the overall rate of polymerization was studied. The molecular weights were determined viscosimetrically. It was found that the average molecular weights of the obtained polymers increase with the increase of both monomer and initiator concentrations and decrease with rise of temperature. Ahram sand leads to a higher polymer yield and a lower average molecular weight than in case of Natron sand. The stereoregularity of the obtained polymers was determined with a 60 MHz NMR spectrometer.     

甲基丙烯酸甲酯/丙烯酸/水反相无皂微乳液体系的聚合

采用滴定法描绘了甲基丙烯酸甲酯（MMA）/丙烯酸（AA）/H₂O无皂微乳液体系的三元相图,用电导率法对单相微乳液区域进行了类型划分.在相图研究的基础上,考察了引发剂（AIBN）用量、体系AA含量和水含量对MMA/AA/H₂O反相无皂微乳液体系聚合速率的影响.结果表明,聚合速率随引发剂用量和AA含量的增加逐步加快,随体系水含量的提高出现极大值.得到动力学关系,表明AA的乳化促进作用显著,聚合在连续相进行的同时亦在分散相液滴内进行.此外,环境扫描电镜的测试结果表明,所得聚合产物具有明显的孔穴结构.     

Polymerization of methyl methacrylate with Ziegler-Natta catalysts

The polymerization of methyl methacrylate with Ziegler-Natta catalyst, anionic catalyst and gamma radiation has been shown possible at temperatures below 0°C. A free radical mechanism is suggested in the case of Ziegler-Natta catalyst which is known for a coordinate anionic polymerization mechanism. In view of this, the Ziegler-Natta catalysts based on vanadium compounds were investigated for the polymerization of methyl methacrylate. They were found effective for polymerization of methyl methacrylate at, and around, room temperature. The structure of the polymer was stereoblock. This apparently leads to the conclusion that the mechanism of polymerization of methyl methacrylate was not free radical but coordinate anionic. Similarly, the catalyst system of chromium acetyl acetonate and aluminium triethyl polymerized methyl methacrylate at and around room temperature into an highly stereoblock structure containing high isotacticity.     

Vinyl polymerization, 399. Polymerization of methyl methacrylate with sodium polystyrenesulfonate in presence of polyethyleneglycol

The effect of polyethyleneglycol on the radical polymerization of methyl methacrylate initiated with an aqueous solution of sodium polystyrenesulfonate was studied. Under the definite condition, the conversion of methyl methacrylate raised from 6.6 to 100% by the addition of polyethyleneglycol. It was concluded that polyethyleneglycol acted only as a host of Na⁺, but not as a phase transfer catalyst.     

AGET ATRP of methyl methacrylate catalyzed by FeCl3/iminodiacetic acid in the presence of air

The recently developed living free-radical polymerization system, atom transfer radical polymerization using activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP), was used for methyl methacrylate (MMA) polymerization in the presence of a limited amount of air, using a novel catalyst system based on iron (FeCl₃) complexes with iminodiacetic acid (IDA) and using ascorbic acid (VC) as a reducing agent. The kinetics of AGET ATRPs of MMA with different amounts of VC in the presence of air was investigated. The results of the polymerizations demonstrated the features of “living”/controlled free-radical polymerization such as the number-average molecular weights increasing linearly with monomer conversion and narrow molecular weight distributions (M_w/M_n = 1.31–1.44).     

Polymerization of methyl methacrylate in water in presence of the metal oxides TiO2 and Cu2O

Rates of sodium bisulfite-initiated polymerization of methyl methacrylate in water were determined in absence and in presence of the metal oxides TiO₂ and Cu₂O at 30°, 40°, 50°, and 60°C. Cuprous oxide and titanium dioxide enhanced the rate of polymerization and reduced the molecular weight as compared with the figures obtained in absence of oxide, the effect of the former being more pronounced than the latter. With TiO₂, the rate was increased from 2.3 to 3.2 × 10^?5, while with Cu₂O, it was increased to 8.6 × 10^?5 mole/l./sec, both at concentrations of 9 g/l. water. The apparent energy of activation for the polymerization of methyl methacrylate between 40°C and 50°C was found to be 15.6 kcal/mole in absence of the metal oxides, and 7.6 kcal/mole and 2.8 kcal/mole in presence of titanium dioxide and cuprous oxide, respectively. The number-average molecular weight was found to decrease slightly with the addition of TiO₂ but to decrease greatly when Cu₂O was added.     

Photopolymerization of methyl methacrylate in the presence of saccharide

Photopolymerization of methyl methacrylate (MMA) in aqueous solution of saccharide was investigated. Glucose, cellobiose, maltose, and fructose accelerated the photopolymerization in the hard glass system, but α-methyl-d-glucoside was inactive. On the other hand, on remarkable effect of saccharide except fructose was observed in the quartz glass system. A conversion in the hard glass system increased with irradiation time and with concentration of saccharide, which showed the effect in the order of ketose > aldose > nonreducing saccharide. Scission of glucosidic bonds and decomposition of reducing groups of saccharide molecule took place in the quartz glass system, but there was no reduction in the reducing power of saccharide in the hard glass system. By studying the ESR of the photoirradiated system containing saccharide, MMA, and water, no radical of saccharide was found in hard glass systems, but an increase in growing radical of MMA was clearly observed in systems with the coexistence of ketose and aldose, while α-methyl-d-glucoside was inactive. It is believed, therefore, that both ketose and aldose contribute effectively to initiate the photopolymerization without any change in their own structures. On the other hand, reducing groups of saccharide play a very important role in the sensitizing action of the initiation.     

Radical polymerization of methyl methacrylate in the presence of magnesium bromide as the Lewis acid

We carried out the radical polymerization of methyl methacrylate (MMA) at 0–80°C in the presence of magnesium bromide. The polymerization rate and the molecular weight of the resulting polymers increased according to the amount of the added magnesium bromide as the Lewis acid. It was revealed that the microtacticity of the polymer depended on the amount of magnesium bromide. The effects of the solid surface of magnesium bromide, which is partly soluble in the polymerization systems, were also investigated. The results obtained in this work were compared with the results reported for the polymerization systems in the presence of the other Lewis acids. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 290–296, 1999