摘要:

AbstractThe paper describes the synthesis ofN‐2/4‐toluyl methacrylatoethyl carbamates using 2/4‐toluyl isocyanate and 2‐hydroxyethyl methacrylate. Homopolymerisation and copolymerisation of these novel monomers with methyl methacrylate was carried out using benzoyl peroxide as an initiator and tetrahydrofuran as solvent. Photopolymerisation ofN‐4‐toluyl methacrylatoethyl carbamate could be carried out without the use of photosensitiser. Structural characterisation of copolymers was done using1H‐NMR. Thermal stability of copolymers was evaluated in a nitrogen atmosphere by dynamic the

ISSN:0959-8103    

DOI:10.1002/pi.4990290202

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe micellar polymerisation of ionic surfactants such as allyldodecyl‐dimethylammonium bromide and 3‐dodecyl‐1‐vinyl imidazolium iodide has been studied by conductimetry in aqueous solution. The polymerisation was carried out using two different sources of γ rays directed into solutions of surfactant above the critical micellar concentration. Conductimetry is shown to be a very good physicochemical method for analysis of these solutions. The results showed different behaviour for the two surfactants, which has highlighted a change in the structure of their aggregates which led to the assumption of an interaction between the polymers of high mass and different products of the polymerisation (oligomers, products of degradation, monomers etc.). Ultrafiltration experiments coupled with1H‐NMR and conductivity analysis confirm these a

ISSN:0959-8103    

DOI:10.1002/pi.4990290203

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractElectron beam irradiation of ethylene‐vinyl acetate copolymer (EVA) film results in a marked depression of sorption of flavour compounds. This effect is presumed to be brought about by radical reactions, following changes in the structure. The crosslinking density and gel fraction increased with irradiation dose, and the maximum percent gel reached 70% for 20 Mrad‐50g kg−1EVA film, 35% for 20 Mrad‐95g kg−1EVA film and 50% for 10 Mrad‐150g kg−1EVA film.In calculating the ratio of scission to crosslinking events, it was found that EVA film is a polymer of the scission type. The degree of crystallinity,Xcdecreased significantly with increasing irradiation dose in all irradiated films. For unirradiated films,Xcdecreased with increase in vinyl acetate content, which suggests that crystalline regions of EVA film are primarily composed of ethylene units. Therefore, the scission reaction may predominantly take place in the crystalline region, resulting in the formation of methyl or end vinyl groups. This was supported by measuring the film density, peak melting temperature and st

ISSN:0959-8103    

DOI:10.1002/pi.4990290204

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe crosslinked structure of irradiated ethylene‐vinyl acetate copolymer (EVA) film was examined by means of ESR, IR and pyrolysis‐gas chromatography. The ESR spectrum of 35 Mrad irradiated EVA film with 95g kg−1vinyl acetate content consisted of a three‐line component with an intensity ratio of 1:2:1, a hyperfine structure coupling of 22.4 G andgfactor of 2.0049. Therefore, the spectrum was assigned to the methylene radical with two α protons on the same plane; this radical is formed by loss of a hydrogen atom from the acetoxymethyl group.In pyrolysing EVA films at 500°C, the yield of acetic acid from 10 Mrad‐150 g kg−1film significantly decreased compared with that of unirradiated film, and it decreased with increasing crosslinking density.By measuring the IR spectra of methanolysed EVA films, the following results were obtained: the absorbances at 1740, 1250 and 1050cm−1, attributed to the CO, OCOR and COC groups, respectively, had a marked decrease, whereas the three peaks for 20Mrad film were much stronger than those of unirradiated film. On the basis of these findings, it is suggested that the crosslinking reaction in electron beam irradiated EVA film with lower doses takes place between the acetoxy

ISSN:0959-8103    

DOI:10.1002/pi.4990290205

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe curing of tetraglycidyl‐4,4′‐diaminodiphenylmethane (TGDDM) cured with hexahydrophthalic anhydride, tetrahydrophthalic anhydride and nadic methyl anhydride was studied using static rheological techniques under isothermal conditions in different temperature ranges for each system. 1:1 and 1:0.5 stoichiometric ratios were used in all three TGDDM/anhydride systems analysed. From the gelation times of each system at the different conditions employed activation energies were calculated. Flexural mechanical properties, such as elastic modulus, strength and strain to break, were also investigated for all the three TGDDM/anhydride systems employed for different anhydride weight contents which ranged from 0.5 to 1.34 parts of the anhydride weight corresponding to the stoichiometric composition. Possible reasons to explain the mechanical behaviour shown are disc

ISSN:0959-8103    

DOI:10.1002/pi.4990290206

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA number of copolymers were synthesised by condensing the 2,4‐dinitrophenylhydrazone of resacetophenone with substituted benzoic acids/ phenols and formaldehyde in the presence of sodium hydroxide or hydrochloric acid. The decomposition temperature, solubility and viscosity of the polymers have been determined. The ion‐exchange properties have been studied by using a batch equilibrium method. The distribution of a number of metal ions between an aqueous solution and the resin have been measured. A wide range of pH and variable ionic strengths have been investiga

ISSN:0959-8103    

DOI:10.1002/pi.4990290207

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe thermomechanical and the mechanical properties of a recent series of copolyamides of octanelactam (OL) and laurolactam (LL) (nylon‐8/nylon‐12) were studied. The glass transition temperature (Tg) and melting point (Tm) were determined with dynamic mechanical thermal analyser, and compared to those obtained with differential scanning calorimetry and the activation energy for glass transition was calculated. The copolyamides showed a minimum for tensile strength, yield stress, stress at 100% and modulus and a maximum for elongation at break at the composition 60/40 (OL/LL) which has the lowest crystallinity. Young's modulus against % elongation showed the classification of copolyamides in two groups (rich in OL or LL, respective

ISSN:0959-8103    

DOI:10.1002/pi.4990290208

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe miscibility behaviours of thermoplastic polyurethane elastomers (TPUs) with chlorine‐containing polymers were studied. Four kinds of TPUs containing 20, 40, 60 and 80wt% of poly(caprolactone) (PCL) diol as a soft segment were used for blending. Poly(vinylidene chloride‐co‐vinyl chloride) (P(VDC‐VC)) with a chlorine content of 70%, poly(vinyl chloride) (PVC) and chlorinated polyethylene (CPE) with a chlorine content of 40% were blended with TPUs to study miscibility. The results of optical clarity observation and thermal characterisation suggest that P(VDC‐VC) was miscible with all the TPUs investigated. PVC was only miscible with TPUs containing 40, 60, 80wt% PCL segment, whereas CPE was immiscible with all the TPUs studied. Tensile measurements showed that all the TPU with 60wt% of PCL segment/chlorine‐containing polymer blends were mechanically

ISSN:0959-8103    

DOI:10.1002/pi.4990290209

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractWith a view to study and compare the properties of poly(phenyienc sulfide)s containing carbonyl and sulfonyl backbone units, 1,4‐bis(phenylthio)‐benzene, and bis(4‐phenylthio)diphenyl sulfone, were prepared and subjected to Fricdel‐Crafts type polycondensation with various aromatic diacid chlorides. The resulting polymers had inherent viscosities in the range 0.101—0.141 dl/g. These polymers were not soluble in common organic solvents and exhibited good thermal st

ISSN:0959-8103    

DOI:10.1002/pi.4990290210

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractN‐Aryl methacrylatoethyl carbamate monomers were prepared by reacting phenyl isocyanate/4‐chlorophenyl‐isocyanate and 2‐hydroxyethyl methacrylat, Homopolymerisation and copolymerisation with methyl methacrylate in a tetrahydrofuran solution was carried out using azobisisobutyronitrile/benzoyl peroxide as an initiator at 60°C. Molecular characterisation of polymers was done by intrinsic viscosity determination at 30°C in chloroform and molecular weight determination by gas permeation chromatography using poly(methyl methacrylate) standards. Molecular weight distribution ranged from 1.5 to 2.63. Copolymer composition was determined by using1H‐NMR. Thermal behaviour of the polymers in a nitrogen atmosphere was evaluated using dynamic thermo

ISSN:0959-8103    

DOI:10.1002/pi.4990290211

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY