Reaction of α-oxide groups in graft copolymers of polycaproamide and polyglycidyl methacrylate with thiourea

The effect of a composite of graft copolymers of polycaproamide and polyglycidyl methacrylate on the reaction rate of α-oxide groups with thiourea was determined. A supermolecular effect in the heterophase macromolecular reaction of transformation of α-oxide groups with thiourea was revealed. It was found that the degree of polymer-analog transformations of α-oxide groups into thiirane groups in PCA-PGMA graft copolymers is on the level of 55–70%. Translated from Khimicheskie Volokna, No. 5, pp. 13–16, September–October, 1997.     

Kinetics of graft polymerization to the surface of oriented polycaproamide

Graft polymerization of methyl methacrylate and glycidyl methacrylate initiated from the surface of polycaproamide fibre with a constant rate to a high degree of conversion was demonstrated. The effect of graft polymerization on the character of the change in the relief of the polymer matrix was established. __________ Translated from Khimicheskie Volokna, No. 5, pp. 21–24, September–October, 2006.     

Reaction scheme of graft polymerization of hydroxyethyl methacrylate on polycaproamide using a heat-treated solution of the monomer

A heat-treated solution of hydroxyethyl methacrylate (HEMA) was investigated by the bromide—bromate method, gas-liquid chromatography, and NMR spectroscopy. A scheme of thermal polymerization of HEMA was proposed. Hypothese were advanced concerning the mechanism of graft polymerization of HEMA oligomers to polycaproamide. Volgograd State Technical University. Translated fromKhimicheskie Volokna, No. 5, pp. 13–15, September–October, 1999.     

Fabrication of metal-containing carbon fibre based on modified polycarproamide fibre

Fabrication of elementary carbon fibre materials based on graft copolymers of polycaproamide and poly(dimethylaminoethyl methacrylate) was investigated. The possibility of complexation of the graft polymer with Cu²⁺ and VO²⁺ ions was demonstrated and the catalytic activity of the metal complexes obtained in thermooxidation and carbonization of modified PCA was established. It was found that thermooxidation of modified PCA fibre in the presence of copper- and vanadium-containing compounds results in a nonthermoplastic polymer in softer conditions (with respect to the duration of heat treatment) in comparison to the same process without the corresponding treatment of the fibre. The effect of copper- and vanadium-containing compounds on thermooxidation and carbonization of PCA-PDMAEMA graft copolymers results in a nonbrittle, elementary carbon fibre material with a yield of up to 24–28 wt. %, a 72–80 wt. % concentration of carbon, and 14–16% concentration of the metal. Moscow State Textile Academy. Translated fromKhimicheskie Volokna, No. 1, pp. 3–7, January–February, 1999.     

Synthesis and characterization of side-chain poly(methacrylate)s bearing new azo-moieties

New side-chain poly(methacrylate)s with azo moieties were prepared by free radical copolymerization, starting from methyl methacrylate (MMA) and some original azo-monomers. The chromophore content was evaluated from ¹H-NMR spectroscopy and elemental analyses; all structures exhibited a high content of azobenzene units. UV–Vis measurements have also supported this fact. Reactivity ratios for the methacrylate systems and their corresponding Q–e values were calculated based on several initial feed compositions (MMA and the newly synthesized azo-monomers) using an integral method with its appropriate software. The polymers were also characterized by FTIR, SEC and DSC-TGA techniques. The coloured poly(methacrylate)s exhibited glass transition temperatures between 141 and 168 °C and thermal stabilities up to 306 °C.     

Sorption-Active Modified Chemical Fibres

The effect of topochemistry on polymer-analog transformations of graft copolymers of polycaproamide, hydrated cellulose, and polyvinyl alcohol with polyglycidyl methacrylate under the effect of different amines was established. The amine-containing sorption-active fibres exhibit high activity with respect to heavy metals and platinum-group metals. Moscow State Textile University. Translated fromKhimicheskie Voloka, No. 6, pp. 18–21, November–December, 2000.     

Graft polymerization of hydroxyethyl methacrylate to polycaproamide using a heat-treated solution of monomer

A method of modifying the polycaproamide fibre Megalon is proposed; it consists of introducing a stage of preliminary heat treatment of a solution of the monomer in the graft polymerization process. The basic characteristics of the kinetics of graft polymerization of heat-treated hydroxyethyl methacrylate to PCA were investigated. The induction period decreased to 15 min, the reaction rate increased by 2-2.5 times, and the activation energy decreased by 1.6 times. It was found that the modified PCA fibre prepared by the new method has satisfactory strength and hygienic properties. Volgograd State Technical University. Translated fromKhimicheskie Volokna, No. 6, pp. 11–13, November–December, 1999.     

Poly(methylphenylphosphazene)–Graft–Poly(methyl Methacrylate) Copolymers Via Atom Transfer Radical Polymerization

Atom transfer radical polymerization (ATRP) was used to graft poly(methyl methacrylate), PMMA, onto poly(methylphenylphosphazene), [(Me)(Ph)PN] _n , PMPP. A two-step process was used to convert a portion of the methyl substituents on [(Me)(Ph)PN] _n to –CH₂C(CH₃)₂OH groups and then to bromoalkyl groups, –CH₂C(CH₃)₂OC(=O)C(CH₃)₂Br, the latter of which served as initiation sites for ATRP of methyl methacrylate (MMA) in the presence of CuCl/bipyridine. Variations in the length of the grafted chains were investigated and the graft copolymers were compared to the parent polymer and blends of similar composition. The new bromoalkyl derivatives of [(Me)(Ph)PN] _n and the PMPP–graft–PMMA copolymers were characterized by elemental analysis, ¹H and ³¹P NMR spectroscopy, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC). We dedicate this paper to Professor Harry R. Allcock for consistently maintaining the highest standards in his creative, pioneering work in inorganic rings and polymers.     

Grafting. IV. Graft tercopolymers as antifouling resin

A graft tercopolymer CLR-g-(MMA–TBTMA) based on chlorinated rubber as the backbone and binary copolymer of methyl methacrylate and tributyltin methacrylate as grafted chains has been synthesized. This graft copolymer has been used for the formulation of controlled-release antifouling paints, and leaching rate behavior of toxin from such paints has been studied. The data have been compared with those obtained using controlled-release antifouling paint based on linear chain copolymer of methyl methacrylate and tributyltin methacrylate. The paint based on grafted copolymer is characterized by having a lower leaching rate and reduced time for attainment of steady-state leaching. Raft exposure studies indicate longer antifouling life compared to that of linear chain copolymer-based paint both having the same dry paint film thickness.     

Chemisorption fibres based on graft copolymers: Fabrication and properties. A review

Scientific concepts concerning the characteristics of graft polymerization to oriented polymeric materials and polymer-analog transformations of the graft polymer were elaborated based on systematic studies. The principles of fabrication of sorption-active fibre materials of different types based on graft copolymers and the most important directions of their use were formulated. Moscow State Textile Academy. Translated fromKhimicheskie Volokna, No. 4, pp. 8–16, July–August, 1999.     

Production of carboxyl-containing derivatives of polymethyl methacrylate and polycaproamide graft copolymer

In studying heterophase alkaline hydrolysis of ester groups in graft PMMA chains, the role of the structure of the polymer in the macromolecular reaction in the solid phase was revealed. A decrease in the degree of conversion of graft PMMA with an increase in its content in PCA—PMMA graft copolymer, caused by a change in the packing density of the graft chains, was established. The highest degree of saponification was attained in using graft copolymers containing 25–35% graft PMMA. Chemisorption, carboxyl-containing polycaproamide fibre with a SEC for NaOH of 1.3 mmole/g was obtained as a result of saponification of PCA—PMMA graft copolymers. Translated from Khimicheskie Volokna, No. 5, pp. 22–25, September–October, 2008.     

Fabrication of chemisorption fibres from graft copolymers of polyvinyl alcohol and polyglycidyl methacrylate

Mathematical modeling and optimization of fabrication of PVA-PGMA graft copolymers were conducted. The optimum parameters of graft polymerization which allow obtaining a graft copolymer with a high concentration of graft polymer were established. It was found that fluctuation of the temperature in the range of ±2‡C did not significantly affect graft polymerization. A chemisorption fibre with SEC for HCl of 3.5 mmole/g was fabricated from PVA-PGMA graft copolymers; it exhibits sorption activity with respect to copper ions, and the degree of extraction from dilute solutions is 90–97%. Translated from Khimicheskie Volokna, No. 3, pp. 13–16, May–June, 1998.     

Heterogeneous emulsion graft polymerization of glycidyl methacrylate on a wood matrix

The studies allowed developing an accessible method of synthesis of a highly permeable α-oxide copolymer of wood by emulsion graft copolymerization with the reactive monomer glycidyl methacrylate and establishing the optimum conditions for conducting the process. In modification of a natural polymer with GMA with a concentration of 10% for 60 min at 80 °C in the presence of the Fe²⁺—H₂O₂ initiating redox system with a 2.52 mg/g iron ion content of 0.017%, almost quantitative conversion of the monomer and a high degree of grafting efficacy was attained. The mass fraction of PGMA in the fibre phase is 88–90% and the EN is 19–21%. Translated from Khimicheskie Volokna, No. 5, pp. 18–22, September–October, 2008.     

Manganese(IV)-initiated graft polymerization of vinyl monomers on polyamide fibers

The feasibility of potassium permanganate to induce graft polymerization of vinyl monomers onto nylon 6 was investigated. The graft yield is greatly enhanced by increasing the monomer concentration, reaction time, and temperature. The addition of metallic ions as promoters to the grafting medium accelerates the graft polymerization. A mechanism for grafting was proposed. The activation energy of initiation E_i for methyl methacrylate was calculated and found to be 5 kcal/mole. The overall rate of graft polymerization R_p depends on the monomer concentration.     

Use of new fluorine-containing copolymers for fabrication of fibres with low wettability

The effectiveness of using new fluorine-containing copolymers of different molar and molecular composition for decreasing the wettability of fibres was investigated. It was shown that copolymers of 1,1′-dihydroperfluoroheptyl acrylate and 1,1′, 5-trihydroperfluoroamyl acrylate, 1,1′-dihydroperfluoroamyl methacrylate, and 1,1′, 5-trihydroperfluoroamyl acrylate containing 30–35 wt. % of the second component, which is less expensive and more available, can be used instead of the expensive polymer modifier polyperfluoroheptyl acrylate to decrease the wettability of viscose and polyester fibres and materials based on them, and to give them oil- and acid-repellent properties. Translated from Khimicheskie Volokna, No. 2, pp. 35–37, March–April, 1997.     

Graft copolymers of poly(methyl methacrylate) and polyamide-6 via in situ anionic polymerization of ε-caprolactam and their properties

Graft copolymers of poly(methyl methacrylate) and polyamide-6 (PMMA-g–PA6) were investigated via in situ anionic polymerization of ε-caprolactam, using PMMA precursors with N-carbamated caprolactam pendants (PMMA–CCL) as macroactivators and sodium caprolactamate as catalyst. Three grades of PMMA–CCLs obtained by free radical copolymerization were used for synthesizing the PMMA-g–PA6 copolymers with different PMMA content. The resulting graft copolymer was characterized by Fourier-transform infrared spectroscopy and selective extraction. Scanning electron microscopy is used to clarify the phase morphology of obtained polymer by fracture surface. The thermal property, crystallinity and dimensional stability of graft copolymer were studied using differential scanning calorimetry, X-ray diffraction and water absorption measurement. The results show the T_g of graft copolymer is higher than that of neat PA6, but the onset and peak points of graft copolymer melting point are shifted to lower temperature. The percentage crystallinity and water absorption of PMMA-g–PA6 copolymer decrease with increasing PMMA content, but the crystal structure of PA6 is scarcely affected by the presence of PMMA. Graft copolymers have improved dimensional stabilities relative to neat PA6. Upon the incorporation of 19.9 wt% PMMA into PA6, the water absorption of PMMA-g–PA6 copolymer has been reduced from 4.8 for neat PA6 to 2.1%.     

Supercritical Fischer-Tropsch synthesis: The effect of nonideality of the reaction mixture on the reaction rate

A kinetic model is derived from experimental data for the Fischer-Tropsch reaction on a precipitated iron catalyst. In this model, the effect of nonideality of the reaction medium on the reaction rate is taken into account by introducing fugacity coefficients derived from a modified Redlich-Kwong-Soave equation of state. Coefficients of the Schulz-Flory distribution for saturated and unsaturated hydrocarbon products were calculated as functions of CO and H₂ fugacities in the reaction mixture. The proposed kinetic model is applicable atT= 523–623 K andP = 6–100 atm. A method based on the calculated critical parameters of the reaction mixture is proposed for the selection of suitable supercritical solvent and for the optimization of its concentration. The reaction rate and the total yield of C_nH_2n (n ≥ 2) olefins (including the desired fraction C₅–C₁₁) under supercritical conditions were demonstrated to be essentially higher than those for the reference process carried out in the absence of solvent.     

Adhesion studies of tyre cords with rubber. I. Synthesis and characterization of natural rubber graft copolymers

Glycidyl methacrylate and N-vinyl pyrrolidone have been grafted onto natural rubber at 32°C using the simultaneous cobalt-60 irradiation technique. The natural rubber samples were swollen in the monomers for 24 h and thereafter subjected to gamma irradiation. The homopolymers formed in the graft copolymerization reactions and unreacted monomer were removed by solvent extraction using acetone and methanol for glycidyl methacrylate and N-vinyl pyrrolidone monomer, respectively. The influence of total dose and monomer concentration on the graft parameters was investigated. The dependence of the rate of grafting on the monomer concentration was found to be 0.93 and 0.80 for glycidyl methacrylate and N-vinyl pyrrolidone, respectively. DSC and TGA studies of the polymers were undertaken. Grafted copolymers based on glycidyl methacrylate were relatively less thermally stable compared with ungrafted natural rubber.     

Properties of optically transparent materials under quasi-entropic compression

Variation in the refractive index in polymethyl methacrylate and lithium fluoride under quasi-entropic loading was studied experimentally. The values of the refractive index and the correction coefficient in the formula for the mass velocity were determined. The results obtained for quasi-entropic loading are compared with available data for shock-wave compression of the materials studied. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 3, pp. 116–120, May–June, 2006.     

Microwave-assisted synthesis and characterization of polyacrylamide grafted co-polymers of <Emphasis Type="Italic">Mimosa</Emphasis> mucilage

Response surface methodology was applied to optimize the microwave-assisted graft co-polymerization of acrylamide on Mimosa pudica seed mucilage. The effect of variables, microwave power and time of exposure, concentrations of acrylamide, mucilage and ammonium persulfate on grafting efficiency of graft co-polymerization was screened using Plackett–Burman experimental design. The results revealed that the concentration of acrylamide and mucilage are the most significant variables, which were further optimized using, a central composite design. A second-order polynomial equation fitted to the data was used to predict the response in the optimal region. The optimal grafting parameters provided graft co-polymer with grafting efficiency close to the predicted values. The proposed mathematical model is found to be robust and accurate for graft co-polymerization of acrylamide and Mimosa mucilage consistent with goals of maximizing grafting efficiency. The results of FT-IR, DSC, XRD, and SEM studies confirmed the formation of graft co-polymer of acrylamide and Mimosa mucilage.