Organotin polymers: 6. Copolymerization parameters for tri-n-butyltin maleate, acrylate and methacrylate with some vinyl monomers

The monomer reactivity ratios for the copolymerization of methyl methacrylate (M₁), styrene (M₁), butyl acrylate (M₁) and acrylamide (M₁) with tri-n-butyltin maleate (M₂) have been found to be r₁ = 15.40, r₂ = 0.01; r₁ = 6.70, r₂ = 0.05; r₁ = 9.39, r₂ = 0.11; and r₁ = 122.44, r₂ = 0.06, respectively. Also, the copolymerization parameters of acrylamide (M₁) with tri-n-butyltin acrylate (M₂) or methacrylate (M₂) were as follows: r₁ = 0.11, r₂ = 0.82; and r₁ = 1.46, r₂ = 0.85, respectively. The Q and e values for the organotin monomers (tri-n-butyltin maleate, acrylate and methacrylate) were calculated from the monomer reactivity ratios determined in the present and previous studies. Copolymerization reactions were carried out in solution at 70°C using 1 mol% AIBN, and the copolymer compositions were determined by tin analysis. The structure of the tri-n-butyltin maleate and the prepared copolymers was investigated by i.r. spectroscopy.     

Grafting. III. Copolymerization of methyl methacrylate and methacrylic acid

The method of graft copolymerization of methyl methacrylate on halogen-containing polymer has been utilized for grafting of methyl methacrylate–methacrylic acid monomer pair onto poly(vinyl chloride) and chlorinated rubber. Substantial grafting could be obtained by using the method reported earlier. However, the compositions of the grafted chains are found to deviate appreciably from the compositions calculated from r₁ and r₂ values reported in literature. The reactivity ratios for this pair of monomers have been therefore evaluated using azobisisobutyronitrile and n-butane thiol–dimethyl sulfoxide as initiators. The anomalies of the grafted chain compositions have been discussed and an explanation presented on preferential solvation.     

Organotin polymers. IX. Copolymerization parameters of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate

Copolymerization reactions of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate were carried out in solution at 70°C using 1 mol% azobisisobutyronitrile as a free radical initiator. The copolymer compositions were determined by chemical analysis as well as from ¹H-NMR data. The monomer reactivity ratios for copolymerizations of di-(tri-n-butyltin) itaconate with styrene and methyl methacrylate have been found to be r₁ = 0.228, r₂ = 0.677, and r₁ = 0.220, r₂ = 1.635, respectively. The sequence distribution of the triad fractions were calculated from reactivity ratios and compared with those obtained from ¹H-NMR data.     

Copolymerization of styrene. IV. Copolymerization with esters of benzylidenecyanoacetic acid

Styrene was copolymerized in bulk with a number of esters of benzylidenecyanoacetic acid. The kinetic scheme of all pairs fitted the improved scheme of copolymerization, taking into account the effect of the penultimate unit. The Alfrey-Price Q and e values were calculated. Using the modified Taft equation, log (1/r₁) = ρ^*σ^* + δE_s, it was found that the relative reactivities of the ester monomers toward the polystyryl radical were correlated by the polar substituent constants σ^* of the ester alkyl groups (ρ^* = 0.14) and not by their steric substituent constants E_s (δ = 0.008).     

酸烯酯化合成甲基丙烯酸叔丁酯工艺研究

以甲基丙烯酸、异丁烯为原料,叔丁醇为烯烃阻聚剂,采用固定床反应器进行酸烯酯化合成甲基丙烯酸叔丁酯。探讨了酸烯投料比、反应温度、反应压力及进料空速对酸烯酯化反应的影响。结果表明,最佳反应条件为:酸烯摩尔比为3,反应温度40℃,反应压力0.5 MPa,进料空速为4 h-1。在此条件下,甲基丙烯酸转化率53.4%,异丁烯转化率80.6%,甲基丙烯酸叔丁酯选择性达96.5%。     

Organotin polymers. XV. Azeotropy in terpolymerization reactions of tributyltin acrylate or methacrylate with itaconic acid or dimethylitaconate and acrylonitrile

Ternary copolymerization of tri-n-butyltin acrylate (TBTA) or methylacrylate (TBTMA) with itaconic acid (IA) or dimethyl itaconate (DMI) and acrylonitrile (AN) were carried out in solution at 70°C in the presence of a free radical initiator. Experimental terpolymerization data agreed well with calculations based on the Alfrey-Goldfinger equation. Ternary azeotropic compositions for TBTA-IA-AN, TBTMA-IA-IA, and TBTMA-DMI-AN systems were 39.0 : 26.1 : 34.9, 51.7 : 10.5 :37.8, and 00.3 : 66.3 : 33.4 mol %, respectively. Also, “pseudo-azeotropic” regions were indentified where the deviation between feed and polymer compositions is very small.     

Copolymerization via zwitterion of methacrylic acid and ethyleneimine

Summary The copolymerization without initiator of methacrylic acid (MA) as nucleophilic monomer with ethyleneimine (EI) as electrophilic monomer in solution at 35°C was investigated. Copolymers are insoluble in water and in common organic solvents as CHCl₃, DMF, MeOH and they were characterized by IR spectroscopy and elemental analyses. Six copolymers were examined as resins with retention properties for copper(II), iron (III) and uranium (VI).     

Synthesis,and NMR and thermogravimetric characterisation of block polymers of methyl methacrylate and methacrylic acid

Block polymers of methyl methacrylate and methacrylic acid have been prepared using the technique of enolate-initiated anionic polymerisation, employing trimethylsilyl methacrylate as a precursor for the methacrylic acid component. The structure of the product has been characterised by infra-red and NMR spectroscopy, and by thermogravimetric analysis.     

Chemical transformations of polymers,XXI. Imidazole containing polymers from crosslinked macroporous poly(methacrylic acid esters) with reactive sulfoester groups

New imidazole containing polymers were synthesized by nucleophilic substitution reactions of poly(ethylene methacrylate arylsulfonates) with imidazole, benzimidazole and some of their derivatives. The reaction time and the solvents used had varying effects on the binding rates. The conversion was best reproducible at high reaction speed in ethanol.     

Study of ternary component polymer complexes of poly(methacrylic acid) and poly(acrylic acid) with complementary polymers

Ternary component polymer complexes have been prepared from poly(acrylic acid) and poly(methacrylic acid) with complementary polymers, such as poly(vinylpyrrolidone) and poly(ethylene oxide). The formation of ternary complexes, selective complexation, and mutual compatibility of the complementary polymers attached to the same polycarboxylic acid chain, have been studied by several techniques, such as viscometry, turbidimetry, potentiometry, conductometry, and IR spectra.     

Organotin polymers XIV. Synthesis and copolymerization reactions of p-acryloyloxy-tri-n-butyltin benzoate with some vinyl monomers

p-Acryloyloxy-tri-n-butyltin benzoate (ABTB) was prepared by the reaction of p-hydroxy-tri-n-butyltin benzoate and acrylic acid in the presence of dicyclohexylcarbodiimide. The monomer reactivity ratios for the copolymerizations of ABTB (M₁) with methyl acrylate (M₂), ethyl acrylate (M₂), n-butyl acrylate (M₂), methyl methacrylate (M₂), styrene (M₂) and acrylonitrile (M₂) have been found to be r₁ = 0.080, r₂ = 1.046; r₁ = 0.039, r₂ = 1.585; r₁ = 0.019, r₂ = 2.076; r₁ = 0.150, r₂ = 1.710; r₁ = 0.113, r₂ = 1.339 and r₁ = 0.007, r₂ = 2.853, respectively. The Q and e values for the prepared organotin monomer were calculated. Copolymerization reactions were carried out in solution at 70°C using 1 mol-% azobisisobutyronitrile. The structure of the ABTB monomer and the prepared copolymers was investigated by IR and ¹H-NMR spectroscopy.     

Organotin polymers. IV. Binary and ternary copolymerizations of tributyltin acrylate and methacrylate with styrene,allyl methacrylate,butyl methacrylate,butyl acrylate,and acrylonitrile

The monomer reactivity ratios for the copolymerization of tributyltin acrylate with styrene and allyl methacrylate have been found to be r₁ = 0.213, r₂ = 1.910 and r₁ = 0.195, r₂ = 2.257, respectively. Also, the copolymerization parameters of tributyltin methacrylate with styrene and allyl methacrylate were as follows: r₁ = 0.256, r₂ = 1.104 and r₁ = 2.306, r₂ = 1.013. Copolymerization reactions were carried out in solution at 70°C using 1 mole % AIBN, and the copolymer compositions were determined by tin analysis. Ternary copolymerization of the three systems butyl methacrylate–tributyltin methacrylate–acrylonitrile, butyl acrylate–tributyltin methacrylate–acrylonitrile, and styrene–tributyltin acrylate–acrylonitrile have been studied, and the terpolymer composition of each system was determined through tin and nitrogen analyses. The variation of instantaneous and average terpolymer composition with conversion fit satisfactorily the experimental results over a wide range of conversion.     

乙炔羰基合成丙烯酸及酯的催化剂研究进展

综述了乙炔羰基化法合成丙烯酸及酯的镍基、钯基、金属原子簇及其负载化合物等催化体系的特点和最新研究进展,介绍了该工艺路线在阻聚及防结炭等方面的最新研究成果,认为开发新型催化剂是该工艺路线的核心技术。     

Thickening of butyl acrylate/styrene/2-hydroxyethyl methacrylate/acrylic acid lattices with dispersion of crosslinked ethyl acrylate/methacrylic acid copolymer

Thickening of lattices of styrene–acrylic copolymers containing a small amount of acrylic acid and various amounts of 2-hydroxyethyl methacrylate (HEMA) with alkali-swellable dispersion of crosslinked ethyl acrylate/methacrylic acid copolymer has been studied using capillary viscometry and dynamic and steady shear measurements. The higher the amount of HEMA incorporated into the latex copolymers, the stronger the thickening effect is. A comparison of flow behavior of thickened systems with those of neat lattices confirmed a significant influence of the effective volume fraction of alkalinized swollen latex particles on the thickening process. Under these conditions, to obtain the same rheological properties, the necessary amount of thickener was lower for the latex copolymers with higher amounts of HEMA because a part of the thickener volume fraction was replaced by an increased volume fraction of swollen latex particles. These findings indicate weakly interacting dispersion systems without strong compression of particle domains.     

用甲基丙烯酸改善PMMA光纤芯材的耐热性

用甲基丙烯酸(MAA)改性PMMA,使其维卡软化点提高了20~23℃,透光率未降低。     

Specific enthalpies of combustion of some acrylic polymers

Specific enthalpies of combustion of six acrylic polymers and polystyrene were measured by bomb calorimetry. The negative specific enthalpy of combustion (calorific value) was found to increase linearly with the net reducing valencies of the polymer.     

Kinetics and mechanism of reaction between acrylic acid or methacrylic acid and some oxiranes in the presence of N,N-dimethylaniline catalyst

The reactions of acrylic and methacrylic acids in ethylene oxide, propylene oxide, or glycerin epichlorohydrin were carried out in DMF in the presence of N, N-dimethylaniline catalyst. The kinetic equations describing these equations have been devised and activation parameters ΔH^#, ΔS^#, and ΔG^# calculated. The mechanism of the reaction has been proposed and verified by using kinetic and instrumental methods © 1998 SCI     

Preparation and characterization of polyelectrolyte copolymers containing methyl methacrylate and 2-hydroxyethyl methacrylate. I. Polymers based on methacrylic acid

Acidic polyelectrolyte copolymers containing 2-hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), and methacrylic acid (MAA) were prepared by free radical polymerization to high conversion in solution. Copolymer yields were obtained by gravimetry (all in the 30–50% range), relative molecular weights estimated by intrinsic viscosity measurements (all in the 50–70 cc/g range), tacticity by ¹³C nuclear magnetic resonance (NMR) spectroscopy (all polymers predominantly syndiotactic with some atactic content), and composition by acid/base titrations in conjunction with ¹H-NMR spectroscopy (all close to the monomer charge ratios). Acid strengths or apparent pKa's were examined as a function of extent of ionization. Measurements performed in water indicated that the compact/extended coil transformation in predominantly syndiotactic polymethacrylic acid occurs also in copolymers of similar tacticity containing moderate to high concentrations of MAA. The apparent pKa of such polymers containing only small amounts of MAA did not vary with extent of ionization, indicating a low degree of interaction between the acid groups. In copolymer pairs containing similar amounts of MAA but differing HEMA and MMA contents, the polymer containing more HEMA appeared the stronger acid, presumably due to a better solvation of that polymer which would increase the net spatial charge–charge separation and decrease cooperative effects that lead to suppressed ionization.     

Copolymerization of 2-acrylamido-2-methylpropane sulfonic acid with 2-hydropropyl methacrylate

Summary Copolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS, monomer 1) with 2-hydropropyl methacrylate (monomer 2) was conducted in pure water at 80°C. The reactivity ratios estimated from the compositional data of the copolymers at low conversion are r₁=0.04±0.04 and r₂=6.30±0.48, and values of Q₁ and e₁ are 0.16 and 1.37, respectively. Copolymer microstructure predicted by statistical calculation shows mean sequence length of M_I shorter than 2. These results can be attributed to the strong repulsion between the ionized chain radical and charged monomer of AMPS.