Graft Copolymerization of Methyl Methacrylate onto Nylon 6 Using Thallium(III) Ions as Initiator

Abstract

Graft copolymerization of methyl methacrylate onto nylon 6 was investigated in aqueous perchloric acid medium using thallium(III) ions as initiator. The rate of grafting was evaluated by varying the concentrations of monomer, initiator, acid, and temperature. The rate of grafting was found to increase with an increase of both monomer and initiator concentrations. The graft yield was found to increase with an increase in the acid concentration up to 0.49 mL^?1, and beyond this concentration of perchloric acid the graft yield was found to decrease. It also increased with an increase of temperature. From the Arrhenius plot the overall activation energy was found to be 3.9 kcal/mol. The effects of inhibitors, various solvents, inorganic salts, and swelling agents on graft yield were studied. A suitable kinetic scheme has been proposed and a rate equation has been derived.     

Grafting onto Starch. IV. Graft Copolymerization of Methyl Methacrylate by Use of AIBN as Radical Initiator

Grafting of poly(methyl methacrylate) onto starch has been investigated in aqueous medium by using AIBN as radical initiator. Starch-g-PMMA has been characterized by determination of starch in the graft copolymer. Percentage of grafting has been determined as functions of concentration of monomer, concentration of initiator, reaction time, and temperature. From scanning electron microscopic studies, evidence for grafting of PMMA onto starch has been presented.     

Graft Copolymerization of Methyl Methacrylate onto Chitosan Initiated by Potassium Ditelluratocuprate(III)

A novel redox system, potassium ditelluratocuprate(III) (DTC)–chitosan, was employed to initiate the graft copolymerization of methyl methacrylate (MMA) onto chitosan in alkali medium. The effects of reaction variables, such as the initiator concentration, ratio of monomer to chitosan, the pH value, as well as reaction temperature and time were investigated, and the grafting conditions were optimized. Graft copolymers with both high grafting efficiency (>90%) and percentage of grafting were obtained, and the rate of polymerization is higher, which indicated that the DTC–chitosan redox system is an efficient initiator for this graft copolymerization. The structures and the thermal property of chitosan and chitosan–g–PMMA were characterized by infrared spectroscopy (IR), X‐ray diffraction and thermogravimetric analysis (TGA). A mechanism is proposed to explain the generation of radicals and the initiation. The graft copolymer was used as the compatibilizer in blends of terpolyamide and chitosan. The scanning electron microscope (SEM) photographs indicated that the graft copolymer improved the compatibility of the blend.     

Graft Copolymerization of Methyl Methacrylate onto Poly(Ethylene Terephthalate) Fibers Using Benzoyl Peroxide

Abstract

The graft copolymerization of methyl methacrylate onto poly(ethylene terephthalate) fibers has been studied using benzoyl peroxide as initiator. The grafting reactions were carried out within the 70 to 90°C temperature range, and the variations of graft yield with monomer and initiator concentrations were also investigated. The overall activation energy for grafting was calculated as 34.1 kcal/mol. The results of dyeability with the disperse dye suggested that diffusion into the fiber structure was moderately difficult when the graft yield reached 14?15%. The maximum graft yield was obtained at a benzoyl peroxide concentration of 4.00 × 10^?3 M. The decomposition temperature values obtained from thermogravimetric analysis show that the thermal stability of poly(ethylene terephthalate) fibers decreased as a result of grafting. Further, such change in the properties of methyl methacrylate grafted fibers as density, diameter, and moisture regain were also determined.     

Photograft Copolymerization of Methyl Methacrylate and Natural Rubber Using Quinoline-Bromine C.T. Complex as Photoinitiator in Benzene Solution

Photografting of poly(methyl methacrylate), PMMA chains on natural rubber (NR) chain backbones was studied in benzene solution using quinoline-bromine (Q-Br₂) charge transfer complex as photoinitiator and MMA as monomer at 35°C in visible light. Analysis of overall products for determination of grafting efficiencies was done following a method of selective extraction of only the free rubber fraction by benzene-petroleum ether mixtures followed by separation of the NR-PMMA graft copolymer from free PMMA in the residue (taken in benzene solution) by fractional precipitation with methanol. High grafting efficiencies in the range of 75–95% were easily and generally obtained. Effects of variation of concentrations of initiator, rubber, and monomer on grafting efficiencies were examined and reported. Prior photodegradation of the rubber resulted in substantial lowering in grafting efficiencies. Overall mechanism of graft copolymerization has been discussed.     

Studies on the Graft Copolymerization of Methyl Acrylate and Ethyl Acrylate onto Corn Starch Using Potassium Persulfate-Sodium Thiosulphatc as Initiation System

Grafting copolymerizations of methyl acrylate(MA) and ethyl acrylate(EA) onto corn starch, respectively, initiated by potassium persulfate-sodium thiosulphate (KPS-STS) redox system, were studied. The structures of poly(MA)-g-starch and poly(EA)-g-starch were characterized by IR, SEM and X-ray diffraction. Experimental results show that KPS-STS is an efficient initiation system for grafting of MA and EA onto corn starch. The maximum percent grafting was obtained at [KPS] of 6.0× 10~3 mol/L, [STS] of 1.8× 10 5 mol/L, [M] of 6. 0× 101 mol/L, S:L=4:100 at 40℃ for 6 h. The reactivity order is MA>EA.     

Potassium thiocyanate argentates: K3[Ag(SCN)4], K4[Ag2(SCN)6] and K[Ag(SCN)2]

The anions of the title compounds contain [Ag(SCN)₄] units, with the S atoms coordinating to Ag⁺ in a tetrahedral arrangement. Whereas in the isolated anions of tripotassium tetra­thio­cyanatoargentate(I), K₃[Ag(SCN)₄], (I), all SCN^? groups are bonded as terminal ligands, in tetrapotassium di‐μ‐thio­cyanato‐S:S‐bis­[dithio­cyanato­argentate(I)], K₄[Ag₂(SCN)₆], (II), two AgS₄ tetrahedra share one common edge. In poly[potassium [argentate(I)‐di‐μ‐thio­cyanato‐S:S]], K[Ag(SCN)₂], (III), edge‐ and vertex‐sharing of AgS₄ tetrahedra results in infinite [Ag(SCN)₂]^? layers.     

配合物[Cu2(C4H2O6)(Phen)2(H2O)]·8H2O的合成、晶体结构和抗菌活性

在pH≈10的乙醇-水溶液中以硫酸铜、酒石酸和邻菲咯啉反应合成了分子式为[Cu₂(C₄H₂O₆)(Phen)₂(H₂O)]·8H₂O的配合物单晶。用X-射线单晶衍射测定了晶体结构，并研究了配合物对大肠杆菌、金黄色葡萄球菌、枯草杆菌的抗菌活性。晶体属单斜晶系，空间群P2₁。标题化合物为双核铜配合物，2个铜原子配位数不同。Cu(1)是五配位的，具有扭曲的四方锥结构，5个配位原子分别是酒石酸的去质子的羟基氧和羧基氧、邻菲咯啉的2个氮原子及1个水分子的氧原子。Cu(2)为四配位的，配位原子分别是酒石酸的去质子的羟基氧和羧基氧和邻菲咯啉的2个氮原子。分子中Cu(1)…Cu(2)间的距离为0.354 8 nm。存在分子内邻菲咯啉-邻菲咯啉的面—面π-π相互作用，面间距为0.381 3 nm。配合物对大肠杆菌、金黄色葡萄球菌、枯草杆菌具有较强的抗菌活性。     

A Gadolinium Diphenate Coordination Polymer, [Gd2(H2O)2(C14H8O4)3], with One‐dimensional Structure

A hydrothermal reaction of Gd(NO₃)₃ and 2, 2′‐diphenic acid give rise to a new coordination compound equation/tex2gif-stack-2.gif[Gd₂(H₂O)₂(C₁₄H₈O₄)₃] with one‐dimensional structure. Single crystal X‐ray studies shows that the compound has infinite O‐Gd‐O one‐dimensional chains resulting from a bonding between Gd³⁺ cations and diphenate anions. The Gd³⁺ ions are distorted dodecahedra with respect to oxygen atoms. Magnetic investigations show no ordering up to 4K and the compound exhibit photoluminescence at room temperature.     

Copolymerization of Fullerene (C60) and Methyl Methacrylate (MMA) using Triphenylbismuthonium Ylide as a Novel Initiator and Characterization of the Copolymers (C60-MMA)

Copolymerization of fullerene (C₆₀) with methyl methacrylate (MMA) was carried out using triphenylbismuthonium ylide (abbreviated as Ylide) as a novel initiator in dioxan at 60°C for 4 h in a dilatometer under a nitrogen atmosphere. The reaction follows ideal kinetics: R_p∝ [Ylide]^0.5[C₆₀]^?1.0[MMA]^1.0. The rate of polymerization increases with an increase in concentration of initiator and MMA. However, it decreases with increasing concentration of fullerene due to the radical scavenging effect of fullerene. The overall activation energy of copolymerization was estimated to be 57 KJ mol^?1. The fullerene-MMA copolymers (C₆₀-MMA) were characterized by FTIR, UV–Vis, NMR and GPC analyses.     

Grafting Vinyl Monomers onto Cellulose. IX. Graft Copolymerization of Methyl Methacrylate onto Cellulose Using Peroxydiphosphate-Fe(ll) and Mn(ll) Redox Systems

The vacuum or inert-atmosphere condensation of diphenyl isophthalate and 2,2′,3,3′-tetraaminobiphenyl to poly-2,2′-(m-phenylene)-5,5′-bibenzimidazole has been investigated. Evidence from polymer and model compound (diphenylbibenzimidazole) spectral studies, elemental analysis, and analysis of volatile effluent indicates that the prepolymer formed at 260 to 300°C contains both benzimidazole and hydroxybenzimidazoline but is essentially free from phenoxybenzimidazole structures. A mechanism involving loss of phenol initially, followed by evolution of water to give benzimidazole structures, is established from experimental evidence. Polymerization in vacuum to 400°C gives the polybenzimidazole.     

A chiral mixed carboxylate, [Nd4(H2O)2(OOC(CH2)3COO)4(C2O4)2], exhibiting NLO properties

Reaction of a mixture of neodymium carbonate, HCl, oxamic acid and glutaric acid under hydrothermal conditions gives rise to a new mixed carboxylate of neodymium, [Nd₄(H₂O)₂(OOC(CH₂)₃COO)₄(C₂O₄)₂], I. The structure, determined using single crystal X-ray diffraction, comprises a helical column formed by the grafting of the oxalate unit on to helical NdO₉ chains, cross-linked by the glutarate anions. It is noteworthy that the pitch of the helix is equivalent to the length of the oxalate unit. Furthermore, I shows about 1.1 times the SHG activity of urea.     

Novel K/Mn phosphate hydrates,K2Mn3(H2O)2[P2O7]2 and KMn(H2O)2[Al2(PO4)3]: hydrothermal synthesis and crystal chemistry

Two novel K/Mn phosphate hydrates, namely, dipotassium trimanganese dipyrophosphate dihydrate, K₂Mn₃(H₂O)₂[P₂O₇]₂, (I), and potassium manganese dialuminium triphosphate dihydrate, KMn(H₂O)₂[Al₂(PO₄)₃], (II), were obtained in the form of single crystals during a single hydrothermal synthesis experiment. Their crystal structures were studied by X‐ray diffraction. Both new compounds are members of the morphotropic series of phosphates with the following formulae: A₂M₃(H₂O)₂[P₂O₇]₂, where A = K, NH₄, Rb or Na and M = Mn, Fe, Co or Ni, and AM²⁺(H₂O)₂[M³⁺₂(PO₄)₃], where A = Cs, Rb, K, NH₄ or (H₃O); M²⁺ = Mn, Fe, Co or Ni; and M³⁺ = Al, Ga or Fe. A detailed crystal chemical analysis revealed correlations between the unit‐cell parameters of the members of the series, their structural features and the sizes of the cations. It has been shown that a mixed type anionic framework is formed in (II) by aluminophosphate [(AlO₂)₂(PO₄)₂]_∞ layers, with a cationic topology similar to the Si/Al‐topology of the crystal structures of feldspars. A study of the magnetic susceptibility of (II) demonstrates a paramagnetic behaviour of the compound.     

Grafting onto Wool. XV. Graft Copolymerization of MA and MM A by Use of Mn(acac)3 as Initiator

Graft copolymerization of acceptor monomers MA and MMA onto Himachali wool fiber in an aqueous medium was studied by using Mn(acac)s as initiator. Nitric acid was found to catalyze the graft copolymerization. Percentage of grafting and percent efficiency have been determined as functions of the concentration of chelate, nitric acid, monomer, time, and temperature, Under optimum conditions, MMA produced a maximum grafting of 82.5% while MA afforded maximum grafting to the extent of 27.5%. Relative reactivities of MA and MMA toward grafting have been compared with those of EA, BA, and VAc reported earlier from this laboratory. Different vinyl monomers were found to follow the following reactivity order toward grafting onto wool fiber in the presence of Mn(acac)₃: MMA > EA > BA > MA > VAc. An attempt has been made to explain the observed reactivity pattern shown by different vinyl monomers in graft copolymerization reactions.     

Zur solvensfreien Darstellung von Tetramethylammoniumsalzen: Synthese und Charakterisierung von [N(CH3)4]2[C2O4], [N(CH3)4][CO3(CH3)], [N(CH3)4][NO2], [N(CH3)4][CO2H] und [N(CH3)4][O2C(CH2)2CO2(CH3)]

Solvent-free Synthesis of Tetramethylammonium Salts: Synthesis and Characterization of [N(CH₃)₄]₂[C₂O₄], [N(CH₃)₄][CO₃CH₃], [N(CH₃)₄][NO₂], [N(CH₃)₄][CO₂H], and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] A general procedure to synthesize tetramethylammonium salts is presented. Several tetramethylammonium salts were prepared in a crystalline state by solvent-free reaction of trimethylamine and different methyl compounds at mild conditions: [N(CH₃)₄]₂[C₂O₄] (cubic; a = 1 114.8(3) pm), [N(CH₃)₄][CO₃CH₃] (P2₁/n; a = 813.64(3), b = 953.36(3), c = 1 131.3(4) pm, β = 90.03(1)°), [N(CH₃)₄][NO₂] (Pmmn; a = 821.2(4), b = 746.5(3), c = 551.5(2) pm), [N(CH₃)₄][CO₂H] (Pmmn; a = 792.8(7), b = 791.7(3), c = 563.3(4) pm) and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] (P2₁; a = 731.1(2), b = 826.4(3), c = 1 025.2(3) pm, β = 110.1(1)°). The tetramethylammonium salts were characterized by IR-spectroscopy and X-ray diffraction. The crystal structures of the methylcarbonate and the nitrite are described.     

Low Temperature Synthesis of Mn3O4 Nanoparticles Using Starch as Capping Agent

In this communication, manganese oxide (Mn₃O₄) nanoparticles were prepared by a facile solution method using starch as capping agent. The nanoparticles were characterized by means of X‐ray diffraction (XRD) and AFM. The results showed that the Mn₃O₄ nanoparticles were single phase, spherical, and uniformly dispersive. The average particle size was evaluated to be approximately 35 nm.     

Kristallstruktur von Kaliumtriflat‐Butyrolacton, [K3(O3SCF3)3(O2C4H6)2]

Crystal Structure of Potassium Triflate‐butyrolactone, [K₃(O₃SCF₃)₃(O₂C₄H₆)₂] Single Crystals of [K₃(O₃SCF₃)₃(O₂C₄H₆)₂] ( 1 ) have been obtained as a by‐product from the reaction of KNPPh₃ with Yb(O₃SCF₃)₃ in THF with subsequent addition of butyrolactone. The structure of 1 consists of three symmetry‐independent potassium ions which are linked by the oxygen atoms of the triflate ions and the butyrolactone molecules to give a supramolecular structure with layers normal to the crystallographic b‐axis. The carbonyl oxygen atoms of both butyrolactone molecules show a μ₃‐bridging function between three K⁺ ions, one of them is, in addition, coordinated by the ring O‐atom in a chelate manner. 1 : Space group P2₁/c, Z = 4, lattice dimensions at 193 K: a = 1155.0(1), b = 1537.2(1), c = 1531.1(1) pm, β = 100.623(7)°, R = 0.0484.