Showing papers in "British Polymer Journal in 1984"
TL;DR: In this article, the authors present a list of applications of PVP and derives: resines quaternisees dans les reactions triphases, adsorption d'ions metalliques, elimination de contaminants organiques des eaux usees, polymeres reactifs a base de PVP.
Abstract: Applications choisies des PVP et de leurs derives: resines quaternisees dans les reactions triphases, adsorption d'ions metalliques, elimination de contaminants organiques des eaux usees, polymeres reactifs a base de PVP, reactifs d'halogenation, agents d'oxydation, agents reducteurs, applications diverses comme reactifs ou supports, catalyseurs a base de PVP, materiaux resists a base de PVP, diverses autres applications
66 citations
TL;DR: In this article, a statistical analysis of the sequence distribution of the epoxide groups, based on a random epoxidation, showed that there was a good correlation between the value obtained by chemical analysis and the number of epoxide blocks rather than the total number of groups.
Abstract: During the development of chemical methods for determining the epoxide content of epoxidised natural rubber (ENR) two methods were found to give results which were identical but which showed a progressive divergence from values obtained by absolute instrumental methods as the level of epoxidation increased.
Statistical analysis of the sequence distribution of the epoxide groups, based on a random epoxidation, showed a good correlation between the value obtained by chemical analysis and the number of epoxide blocks rather than the number of epoxide groups.
Two further instrumental methods for measuring the total epoxide content, using infra red spectroscopy and differential scanning calorimetry, were developed. Analytical procedures and calibration data are supplied.
A combination of one chemical and one instrumental method can thus provide the absolute level of epoxidation and indicate whether the reaction has proceeded randomly or not, a point of crucial importance in the large scale manufacture of this material.
61 citations
TL;DR: Effet du support polymere sur la cinetique et l'efficacite de couplage des condensations d'aminoacides. as discussed by the authors.
Abstract: Effet du support polymere sur la cinetique et l'efficacite de couplage des condensations d'aminoacides. Changements du taux de gonflement du reseau support au cours de la synthese peptidique. Isolement des sites en relation avec la flexibilite de la chaine de polystyrene
48 citations
TL;DR: Synthese d'ethers halomethylalkyles a chaine longue sans bis-chloromethylether and leur application comme agents d'halometHylation.
Abstract: Synthese d'ethers halomethylalkyles a chaine longue sans bis-chloromethylether et leur application comme agents d'halomethylation
48 citations
TL;DR: In this paper, the composition and microstructure of a blend of bisphenol-A polycarbonate (PC) and poly (butylene terephthalate) (PBT) have been established by a variety of physical methods.
Abstract: The composition and microstructure of a blend of bisphenol-A polycarbonate (PC) and poly (butylene terephthalate) (PBT) have been established by a variety of physical methods. The composition was established by solvent extraction and infra-red spectrophotometry, while the microstructure was determined by these and the additional methods of differential scanning calorimetry and dynamic mechanical thermal analysis. The PBT retained its crystallinity in the commercial blend, (Xenoy CL-100), but blending reduced the main glass-rubber transition of the PC from 147°C to approximately 100°C. Conditioning of the blend at high temperatures resulted in progressive transesterification: 3 minutes at 240°C gave a small but significant effect, while 30 minutes at 270°C yielded large changes in the structure. These findings are important in respect of processing the material, and the limitations which might be incurred in plant recycling of scrap.
43 citations
TL;DR: The 13C n.m. spectra of the title polymers have been completely assigned for a comprehensive range of cis contents (σc = 0−1) and head-tail bias (HT/(HH + TT) = 1 −∞) as discussed by the authors.
Abstract: The 13C n.m.r. spectra of the title polymers have been completely assigned for a comprehensive range of cis contents (σc = 0–1) and head-tail bias (HT/(HH + TT) = 1 −∞). In the unsaturated polymers (II), cis HH dyads are never found, so that all-cis polymers are also all-Ht, but cis TT dyads are formed in cis-trans polymers, equal to the difference between trans HH and trans TT. The olefinic region consists of seven triplets; two each from cis HT and trans HT, and one each from cis TT, trans TT and trans HH. In the case of trans each triplet consists of a main centre peak due to ttt and ctc sequences and two wing peaks due to ttc and ctt sequences, as defined in the text. The upfield peaks also show cc/ct or tt/tc splittings as well as HH/HT or TT/TH splittings in most cases. In the saturated polymers C6 is sensitive to m/r ring dyad sequences. A corrected assignment is given for the hydrogenated polymer of norbornene.
41 citations
TL;DR: In this paper, the amount of cationic soluble polymer fixed by cellulose fibres, whose specific surface area is increased by beating, was determined by a colloidal titration method.
Abstract: The amount of cationic soluble polymer fixed by cellulose fibres, whose specific surface area is increased by beating, was determined by a colloidal titration method. A linear relationship between the polymer uptake and the surface density of carboxyl groups was obtained up to a beating degree of 54°SR. For higher values, the uptake was found to be independent of surface carboxyl groups. These results are interpreted in terms of two mechanisms: a fixation of polycations through an ion-exchange mechanism and an adsorption of polymer by Van der Waals interactions and/or hydrogenbonding.
37 citations
TL;DR: In this article, the polymetric cation poly(hexamethylene biguandinium chloride) [PHMBH+Cl−] was used for quantitative analysis of alginates.
Abstract: A rapid method for the quantitative assay of alginate in solution over a wide concentration range (0.01–0.5 percent) has been developed using the polymetric cation poly(hexamethylenebiguandinium chloride) [PHMBH+Cl−]. The procedure consists of the addition of a known excess amount of PHMBH+Cl− to alginate solutions to precipitate the sample quantitatively and therafter measuring the u.v. absorption of residual PHMBH+C1− in the supernatant. The working range of the assay can be altered by simply adjusting the excess quantity of PHMBH+Cl− which is added during the assay. Assay response is easily reproducible and insensitive to variation in salt concentration (up to 2.5 per cent), pH (5.5–7.6) and temperature (10–60°C). The PHMBH+Cl− method shows good agreement with another recognised method for the assay of alginate solutions. The simplicity of this new method and the short time required to perform it, enhances its suitability as a quick analytical procedure for alginates. Preliminary evidence suggests that assay response is independent of the D-mannuronic acid/L-guluronic acid ratio of alginate.
29 citations
TL;DR: In this paper, the synthesis of acrylate and methacrylate based amphiphiles is described and the critical micelle concentration of each has been determined from conductance and dye absorption data, and the values compare satisfactorily with literature data on similar nonpolymerisable molecules.
Abstract: The syntheses of a number of acrylate and methacrylate based amphiphiles are described. One group consists essentially of quaternary ammonium salts and the other of potassium carboxylates. Two non-ionic species based on oligoethylene oxides are also described. The critical micelle concentration of each has been determined from conductance and dye absorption data, and the values compare satisfactorily with literature data on similar non-polymerisable molecules. The compounds readily oligomerised in bulk, and in the micellar state the dye absorption data also indicated oligomerisation initiated by a free radical source.
22 citations
TL;DR: In this paper, living anionic polydienes are reacted with α, ω-alkylene-chloroamines to generate polymers possessing terminal tertiary amine groups.
Abstract: Methods are described by which living anionic polydienes are reacted with α, ω-alkylene-chloroamines to generate polymers possessing terminal tertiary amine groups. Subsequent reaction with alkyl halides yields materials with quaternary ammonium terminal ligands. Evidence is presented to show that both reaction steps proceed with high efficiency, so that overall conversion is virtually quantitative.
The ionically terminated polydienes exhibit two phase morphology, and the difunctional materials have thermoplastic elastomeric properties.
21 citations
TL;DR: The authors haute resolution and a polarisation croisee/rotation de l'angle magique du polystyrene reticule et de reactifs et catalyseurs supportes sur polystyrenes reticules and gel de silice.
Abstract: Revue de la spectroscopie RMN haute resolution et a polarisation croisee/rotation de l'angle magique du polystyrene reticule et de reactifs et catalyseurs supportes sur polystyrene reticule et gel de silice
TL;DR: In this paper, the thermodynamics of micelle formation by polystyrene-b-polyisoprene block copolymer in N,N′-dimethylacetamide, which is a selectively bad solvent for poly isoprene, has been investigated.
Abstract: The thermodynamics of micelle formation by a polystyrene-b-polyisoprene block copolymer in N,N′-dimethylacetamide, which is a selectively bad solvent for polyisoprene, has been investigated. The micelles have a very narrow size distribution enabling the association process to be treated as a single-stage equilibrium. The temperature dependence of the critical micelle concentration was determined from measurements of scattering intensity against temperature carried out at six concentrations within the range 2.3 × 10−7 to 1.2 × 10−4 mol dm−3. A plot of 1n (c.m.c.) against T−1 gave a value for the standard enthalpy of micellisation (per mole of copolymer chains in the micelle) of − 153 ± 6 kJ mol−1. The standard entropy contribution (-TΔSΘ) to the standard free energy of micellisation was found to be positive. These results are in strong contrast to those reported for synthetic surfactants in aqueous media for which a favourable standard entropy change is the factor mainly responsible for micelle formation.
TL;DR: In this article, the present state of polymer-supported acid catalysis is considered and models describing the catalytic action of gel-like and macroporous resin catalysts are presented.
Abstract: The present state of polymer-supported acid catalysis is considered. Models describing the catalytic action of gel-like and macroporous resin catalysts are presented. By chemical modification of poly (styrene-co-divinylbenzene) matrices, e.g. different ways of sulphonation, nitration, chlorination, fluorination and sulphoalkylation, the activity/selectivity and thermal stability of sulphonic acid resin catalysts can be improved. The synthesis of polymer-supported Lewis acids is described. By comparison to AlCl3 higher catalytic activities are obtained with the use of AlBr3.
TL;DR: Preparation en masse de reseaux enchevetres polyacrylate de butyle/polystene par polymerisation photochimique as discussed by the authors, et al.
Abstract: Preparation en masse de reseaux enchevetres polyacrylate de butyle/polystene par polymerisation photochimique
TL;DR: Carbomethoxylation des olefines as discussed by the authors is a well-known method for the synthesis of aromatiques, and it can be found in many recipes.
Abstract: Carbomethoxylation des olefines. Alkylation des composes aromatiques. Carbonylation oxydante du toluene en acide p-toluique
TL;DR: In this paper, the originine des impuretes photosensibilisantes dans les polymeres is described, and the photostabilisation controlee dans le temps is discussed.
Abstract: L'origine des impuretes photosensibilisantes dans les polymeres. Photostabilisation des polymeres. Stabilisation controlee dans le temps
TL;DR: Catalyse asymetrique par des copolymeres acrylonitrile-alcaloides de quinquina dans des reactions de type Michael.
Abstract: Catalyse asymetrique par des copolymeres acrylonitrile-alcaloides de quinquina dans des reactions de type Michael
TL;DR: In this article, the authors describe an exchange d'halogenure dans les hydrocarbures active par un sel phosphonium revetu de zeolites and polyethyleneglycol.
Abstract: Catalyse de transfert de phase gaz-liquide. Synthese de malonate activee par le carbonate de K revetu de polyethyleneglycol. Echange d'halogenure dans les hydrocarbures active par un sel phosphonium revetu de zeolites
TL;DR: In this paper, it is shown that controlled oxidation processing of polymers in the presence of sulphur-containing compounds can provide a highly effective antioxidant system, which can be used further to promote desirable polymer-antioxidant reactions.
Abstract: The in-service performance of polymers is greatly affected by processing. Mechanooxidation reactions are responsible for the early failure of processed polymers. During processing, the initial formation of macroalkyl and peroxyl radicals is followed by the formation of hydroperoxides which are chiefly responsible for further radical-generating and polymer degradative reactions. Therefore adequate stabilisation is essential for plastics products. Under normal processing conditions, most sulphur-containing antioxidants are partially converted to oxidation products at elevated temperatures. In most cases these reaction products are more effective antioxidants than the compound added initially. It is shown here that controlled oxidation processing of polymers in the presence of sulphur-containing compounds can provide a highly effective antioxidant system. This approach to processing can be used further to promote desirable polymer-antioxidant reactions.
TL;DR: In this paper, theoretical modeling of the electron beam lithographic process and establishing criteria which need to be satisfied for a polymer to behave as a good positive resist are discussed. But they are not considered in this paper.
Abstract: Polymers are widely used as resists in electron beam lithography. This paper is concerned with theoretical modelling of the electron beam lithographic process and establishing criteria which need to be satisfied for a polymer to behave as a good positive resist. The effects of molecular weight, tacticity, solvent selection and sequence structure are discussed. Criteria are presented upon which the design of a new resist material may be based.
TL;DR: In this article, the effect of number-average molecular weight (Mn) and molecular weight distribution (MWD) on the following properties of the polyesters after crosslinking with styrene: (i) water absorption, (ii) initial mechanical properties and (iii) property retention after immersion
Abstract: Unsaturated polyesters have been synthesised and modified to determine the effect of number-average molecular weight (Mn) and molecular weight distribution (MWD) on the following properties of the polyesters after crosslinking with styrene: (i) water absorption, (ii) initial mechanical properties and (iii) property retention after immersion The most important factor was found to be the very low molecular weight ‘tail’ which adversely affected behaviour in several respects. Above a certain Mn, initial mechanical properties were insensitive to the variables mentioned, but mechanical property retention after immersion closely reflected the water absorption behaviour by its dependence on the average chain length and the low molecular weight constituents. The importance of removing such constituents is apparent.
TL;DR: In this paper, the authors describe the preparation of supports par polymerisation en suspension, and the installation of supports in resine and greffage, as well as the modification of supports.
Abstract: Preparation de supports par polymerisation en suspension. Parametres de reaction et du reacteur. Structure des supports en resine. Autres supports. Incorporation d'autres especes. Modification chimique des supports. Modification par greffage. Developpements futurs
TL;DR: Combustion avec flamme des polymeres organiques as discussed by the authors : L'inhibition de la combustion de la polymere organique, a.k.a.
Abstract: Combustion avec flamme des polymeres organiques. L'inhibition de la combustion des polymeres
TL;DR: The formulation d'un stabilisant est habituellement choisie sur la base de considerations cout-efficacite et toxicologiques, mais des interactions possibles avec des auxiliaires lies au processus et au produit doivent aussi etre considerees.
Abstract: La formulation d'un stabilisant est habituellement choisie sur la base de considerations cout-efficacite et toxicologiques, mais des interactions possibles avec des auxiliaires lies au processus et au produit doivent aussi etre considerees. Etude du cas du PVC
TL;DR: In this paper, a comparative study of catalytique d'ethers-crown and cryptands fixes sur polystyrene reticule is presented, where the authors compare the catalytic catalytic activity of different types of reticules.
Abstract: Etude comparative de l'activite catalytique d'ethers-crown et de cryptands fixes sur du polystyrene reticule
TL;DR: Preparations par polymerisation du vinyl lineaires and reticules contenant des residus thienyle are described in this paper, where the substituant contenants du mercure est aisement remplace par des substituants iodo, borane ou acide boronique.
Abstract: Preparations par polymerisation du vinyl lineaires et reticules contenant des residus thienyle. Ces polymeres sont plus facilement mercuries que le polystyrene. Le substituant contenant du mercure est aisement remplace par des substituants iodo, borane ou acide boronique. Les polymeres contenant ce dernier substituant peuvent servir de groupes protecteurs pour les diols
TL;DR: A method for the quantitative determination of these groups on intact polymeric xanthan using an internal integration standard dissolved within the sample is described, which can be easily performed on a 60MHz spectrometer equipped with Fourier Transformation and variable temperature control, and simultaneously quantitates both O-acetate ester and pyruvic acid acetal with improved accuracy.
Abstract: Traditional methods for the quantitation of O-acetate ester and pyruvic acid acetal in xanthan gums require hydrolysis procedures followed by determination of acetic acid and pyruvic acid separately either by colorimetric, enzymic or chromatographic assays Some of these assays are time-consuming and involve many solvent extractions, and during the course of these procedures the xanthan sample is destroyed by hydrolysis The methyl protons of both O-acetate ester and pyruvic acid acetal can be detected by 1H nmr spectroscopy, and this paper describes a method for the quantitative determination of these groups on intact polymeric xanthan using an internal integration standard dissolved within the sample The method is non-destructive, can be easily performed on a 60MHz spectrometer equipped with Fourier Transformation and variable temperature control, and simultaneously quantitates both O-acetate ester and pyruvic acid acetal with improved accuracy