Synthesis and polymerisation of maleoyl-L-histidine monomers and addition of histidine to an ethylene-alt-maleic co-polymer

Kinetics of free radical polymerization of methyl methacrylate using potassium peroxomonosulfate as initiator in the presence of benzyltributylammonium chloride (BTBAC) as phase transfer catalyst was studied. The polymerization reactions were carried out under nitrogen atmosphere and unstirred conditions at a constant temperature of 60°C in ethyl acetate/water bi-phase system. The role of concentrations of monomer, initiator, catalyst, temperature, acid and ionic strength on the rate of polymerization (R_p) was ascertained. The orders with respect to monomer, initiator and phase transfer catalyst were found to be 1.5, 0.5 and 0.5 respectively. The rate of polymerization (R_p) is independent of ionic strength and pH. Based on the kinetic results, a suitable mechanism is proposed.     

Emulsion polymerisation of highly water-insoluble monomers

Contrary to an earlier report, monomers (e.g. p-tert-butylstyrene and octadecyl methacrylate) which are less soluble in water than styrene have been found to polymerise in emulsion using persulphate initiation. At 60°C, the order of the Interval II polymerisation rate of octadecyl methacrylate is 0.48 in persulphate concentration and 0.68 in sodium dodecyl sulphate concentration. The rate is increased by addition of methanol to the aqueous phase. Unlike styrene, p-tert-butylstyrene could not be polymerised in aqueous suspension by persulphate in the absence of emulsifier. High emulsifier-monomer ratios were used in these experiments so that it is possible that mini-emulsion droplets were a significant reaction locus.     

Radiation induced ionic polymerisation and grafting of vinyl monomers

Some special aspects of the radiation induced ionic polymerisation and grafting of vinyl monomers will be described. In particular the effects of solvents on the cationic polymerisation of the vinyl ethers will be discussed in detail. The unequivocal free ion nature of the polymerisation makes such information of considerable general interest. Estimates of the propagation rate constants with free cation polymerisation in solvents of different dietectric constants and solvation powers will be presented. Finally, some observations on the radiation induced graft polymerisation of ethyl vinyl ether to poly (vinyl chloride) and to polypropylene will be presented.     

An investigation into the effects of graft polymerisation of vinyl monomers to wool

The grafting of vinyl monomers to wool to confer shrink-resistance can have a number of side-effects, notably changes in dye uptake, tensile behaviour and handle. This work investigated these phenomena as a method of improving specific fibre properties. In addition, an attempt was made to develop a system of industrial, rather than purely scientific, significance. Several systems were examined, in particular a highly efficient and selective system using the redox couple potassium bromate and cobalt diacetate, with monomers such as methyl-, ethyl-and butyl-methacrylate. The effects of co-solvents such as acetone and diethyleneglycol monobutylether were also studied. It was found that both dye uptake and tensile strength could be significantly improved by relatively low levels of grafting without deleterious effects on handle. A novel ‘limiting volume’ model was developed to describe the various stages through which the grafting process proceeds, which explains the observed results, particularly at high levels of grafting where polymer growth is ‘forced’ onto the fibre surface.     

Half-sandwich ruthenium complexes for the controlled radical polymerisation of vinyl monomers

Ruthenium complexes of the type [RuX(Cp^#)(PPh₃)₂] (X=Cl and H; Cp^#=Cp, Cp*, indenyl, and carboranyl) catalyse the radical polymerisation of styrene and n-butyl acrylate, and both the catalyst activity and the degree of control of the polymerisation strongly depend on the Cp^# ligand and the monomer.     

Processing of cellular ceramics by foaming and in situ polymerisation of organic monomers

This paper describes studies on a new processing route for fabricating highly porous ceramics. The method is based on the generation of a foam from an aqueous suspension of ceramic powder and the subsequent stabilisation of the structure by in situ polymerisation of organic monomers. The influence of the slip viscosity on the foam volume and stability was determined using concentrated alumina suspensions containing dispersing agents and two commercial foaming agents. The in situ polymerisation of organic monomers led to fast solidification, resulting in strong, porous bodies which could withstand machining. The resulting ceramic foams consisted of a highly interconnected network of spherical cells with densities as low as 6% of theoretical. The distribution of cell size was dependent both on the density of the specimen produced and on the time for polymerisation onset. The size ranged from approximately 30 to 600 μm. Enlargement of cell size to achieve materials of higher permeability was possible through expansion of the foam via pressure reduction before polymerisation. The creation of highly densified struts between the cells led to flexural strengths as high as 26 MPa. ©     

Thermodynamics of addition polymerisation I. The system trioxane-polyoxymethylene

The thermodynamic functions of trioxane have been calculated at various temperatures in the range 0° to 1,000°k. These results have been used in conjunction with previously published data for trioxane and polyoxymethylene to calculate the enthalpy, entropy and free energy changes associated with the polymerisation of trioxane.     

General expressions of average molecular weights in condensation polymerisation of polyfunctional monomers

A new method, using the propagation expectation defined by Case, is presented to compute directly and simply the general expressions of average molecular weights for condensation polymerisation of polyfunctional monomers. In particular, the weight average molecular weight in systems composed of monomers endowed with both A and B coreactive functional groups is derived.     

Synthesis and electrostatic assembly of an optically active derivative of poly(ethylene-alt-maleic anhydride) with l-phenylalanine as a chiral material

The layer-by-layer (LbL) assembly of polyelectrolytes is an excellent method for the fabrication of functional ultra-thin multilayers. The functional properties of the film depend on the nature of the polyelectrolyte. Thus, to develop new applications for LbL multilayer films, it is first necessary to synthesize new functional polyelectrolytes. We have prepared a novel, optically active polyelectrolyte, an l-phenylalanine derivative of poly(ethylene-alt-maleic anhydride) (PEMA-l-Phe), via ring-opening of the succinic anhydride unit. We have characterized this polyelectrolyte by FTIR, UV–Vis spectroscopy, ¹H NMR, and polarimetric analysis. The specific rotatory power, [α]_D, of the chiral polymer was ?101.3°, greater than that of l-phenylalanine (?35.1°). We fabricated an ultra-thin film of (PEMA-l-Phe)/poly(allylamine hydrochloride) (PAH) with the electrostatic LbL self-assembly method. The assembly of this ultra-thin film was monitored with a UV–Vis spectrophotometer. The results indicate that the absorbance of the multilayer at 210 nm grows exponentially with the number of bilayers, and that the mass of each bilayer is 1.263 times that of the previous bilayer. This multilayer has potential applications in chiral identification and separation.     

Synthesis and polymerisation of new multifunctional urethane methacrylates

New multifunctional urethane methacrylates were synthesised by addition of methacrylates containing a hydroxy group, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate or glycerol dimethacrylate, to α,α,α′,α′-tetramethyl-m-xylylene diisocyanate. The structure of the new monomers was confirmed by IR, ¹H NMR and ¹³C NMR spectroscopy. The photopolymerisation of the crosslinking monomers in bulk using camphorquinone as photoinitiator results in transparent, crosslinked polymers.     

Electroinitiated emulsion polymerisation of vinyl monomers. III. Homopolymerisation and copolymerisation with vinyl acetate

Of the monomers studied, vinyl acetate and vinyl n-caproate are the only ones capable of electroinitiated homopolymerisation in aqueous acidic emulsion. Water solubility does not appear to be the overriding consideration. Activity of the radical would seem to be most important. Copolymerisation with monomers not undergoing homopolymerisation in this system produces good yields of copolymers low in vinyl acetate concentration.     

Synthesis and properties of brominate bismaleimide monomers

Brominated bismaleimides were prepared by reacting 3(4)‐maleimidobenzoylchloride with various bisphenols, using chloroform as solvent and triethylamine as acid acceptor. These monomers were characterized by elemental analysis, infrared (IR), and proton nuclear resonance (¹H‐NMR) spectroscopy. Thermal properties of monomers were accomplished by differential scanning calorimetry (DSC) and dynamic thermogravimetric analysis (ATG). The properties of these compounds were compared with those of monomers derived from bisphenol A and bisphenol A chlorinated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3881–3885, 2006     

Synthesis and characterization of melt-polymerizable aminophthalocyanine monomers

The strategy, synthesis, and characterization of a soluble amine-functionalized phthalocyanine monomer and two examples of its polymerization into optically transparent glasses are reported. A simple, fast, and versatile method for incorporating metal ions into the metal-free phthalocyanine is demonstrated. Measurements of the nonlinear optical properties associated with a lead-substituted phthalocyanine/urethane copolymer are also reported. © 1995 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Synthesis and ring opening metathesis polymerisation of isoxazolino- and isoxazolidino-norbornenes

Isoxazolino- and isoxazolidino-norbornenes, prepared by cycloaddition to norbornadiene of nitrile oxides and nitrones, respectively, undergo ring opening metathesis polymerisation (ROMP) initiated by the Grubbs ruthenium alkylidenes 1 and 2. The structures of the resulting polymeric isoxazolines were established from their NMR spectra by comparison to polynorbornene and to model isoxazolines prepared by nitrile oxide cycloaddition to cyclopentene. The average degree of polymerisation was regulated using an acyclic chain transfer agent (hex-1-ene) affording products with av DP=4-157, and with narrow molecular weight distributions (PDI=1.45-1.65). Oligomeric analogues (n=4,16) with saturated backbones were prepared by reduction with p-toluenesulfonyl hydrazide.     

Synthesis and properties of polyester-based TPUs prepared by solution polymerisation

Abstract

The polyester based thermoplastic polyurethane elastomers (TPUs) were prepared by one-step solution polymerisation to obtain a product with completely linear molecular structure and with excellent solubility. The synthesis technique was determined by investigation of the influence of solvent and catalyst on the viscosity of the reaction system and the mechanical properties of the resulting product. The effects of the molecular structure on the mechanical, damping and crystallisation properties of TPUs were studied in terms of the type of diisocyanate, mass fraction of hard segment, type and molecular weight of soft segment, and type of chain extender. The structure and morphology of TPUs were characterised by FTIR, GPC and AFM analysis. There was microphase separation in the molecules of TPU, in which the hard-segment phase was dispersed in the soft-segment phase.     

Synthesis,characterization and polymerization of waxy monomers

Waxy monomers and crosslinkers, respectively, were synthesized from commercially available waxes by esterification with 2-hydroxyethyl methacrylate, glycerol dimethacrylate, or glycidyl methacrylate or by functionalization with 2-isocyanatoethyl methacrylate. The resulting opaque methacrylates with melting points between 45 and 80°C were polymerized in bulk and in toluene solution in presence of free radical initiators. The obtained polymers were characterized by a broad molecular weight distribution. Opposite to the bulk polymerization, the double bond conversion in solution polymerization is nearly quantitative. The observed volume shrinkage during polymerization is very low due to the high molecular weight of the monomers. Polymerizates containing crosslinking comonomers exhibit improved mechanical stability.     

Synthesis of new metal-containing side-chain monomers and polymers

New metal-containing vinyl monomers, hexyl-6-oxy-{4-[4-(4-carboxy cyclopentadienyl manganese tricarbonyl phenyl)phenyl]benzoyloxy}methacrylate and hexyl-6-oxy-{4-[4-(4-ferrocenoyl phenyl)phenyl]benzoyloxy}methacrylate, and the corresponding homopolymers and random copolymers with hydroxy monomer hexyl-6-oxy-{4-[4-(4-hydroxyphenyl)phenyl]benzoyloxy}methacrylate were synthesized. The compounds were characterized by¹H NMR; their thermal behavior was investigated by means of differential scanning calorimetry. Monomers and polymers containing the ferrocene unit melt at lower temperatures than those derived from the cyclopentadienyl managanese tricarbonyl moiety. The melting temperatures of the monomers and polymers ranged from 399 to about 515 K, Both monomers and polymers failed to exhibit mesogenic behavior. Values ofM _n,M _w,M _w/M _n, and degree of polymerization were obtained by gel permeation chromatography. TheM _n ranged from 16,500 for the copolymer containing hexyl-6-oxy-{4-[4-(4-ferrocenoyl phenyl)phenyl] benzoyloxy}methacrylate and hydroxy monomer hexyl-6-oxy-{4-[4-(4-hydroxyphenyl)phenyl]benzoyloxy}methacrylate at a 1:3 ratio to 26,000 for the copolymer containing hexyl-6-oxy-{4-[4-(4-carboxy cyclopentadienyl manganese tricarbonyl phenyl)phenyl]benzoyloxy}methacrylate and hydroxy monomer hexyl-6-oxy-{4-[4-(4-hydroxyphenyl)phenyl]benzoyloxy}methacrylate at a 1:3 ratio.M _w/M _n ranged from 1.6 in the case of the copolymer containing hexyl-6-oxy-{4-[4-(4-carboxy cyclopentadienyl manganese tricarbonyl phenyl)phenyl]benzoyloxy}methacrylate and hydroxy monomer hexyl-6-oxy-{4-[4-(4-hydroxyphenyl)phenyl]benzoyloxy}methacrylate at a 1:3 ratio to 2.2 in the case of poly(hexyl-6-oxy{4-[4-(4-carboxy cyclopentadienyl manganese tricarbonyl phenyl)phenyl]benzoyloxy}methacrylate).     

AB型聚对苯二甲酰对苯二胺(PPTA)单体的合成与应用

针对传统的聚对苯二甲酰对苯二胺(PPTA)聚合工艺中二单体等当比难以控制而使纤维相对分子质量小造成无法达到最佳力学性能的问题,创新研究AB型PPTA新单体4-(4-氨基苯胺羰基)苯甲酸(APBA)的合成工艺。APBA可用于制备酰氯化物或直接聚合成PPTA。结果表明:以对甲氧羰基苯甲酰氯(MBC)和对硝基苯胺为原料,经缩合、水解、还原制得APBA,总收率为88.4%,纯度为97.6%。APBA再经均缩聚制得PPTA,其特性黏数达0.9 dL/g。