ISSN:0007-1641    

DOI:10.1002/pi.4980090402

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractCationic derivatives of the title copolymers are water‐soluble, materials which adsorb onto fabrics when applied from aqueous solution and render the substrate oleophobic and hence more resistant to staining by oily soils. The effects of the polymer finish on soil‐removal and redeposition during washing are discus

ISSN:0007-1641    

DOI:10.1002/pi.4980090403

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractSome data related to the preparation of carbon fibre composites is summarised.A limited investigation concerned with presenting markedly different fibre surfaces to the resin by coating with metals and stearic acid is also described.There are carbon fibre surface treatments which lead to improved shear strength, but it is not clear how they are affecting the fibre surface. It also seems likely that some facets of the processing technique can have a large effect on composite quality as indicated by shear strength measurements.The difficulties in interpreting results and identifying sources of variability points to the advisability of statistically planned experiments to assess the significance of changes when investigating possible materials and processing improvements.

ISSN:0007-1641    

DOI:10.1002/pi.4980090404

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractViscosity and density data have been obtained for aqueous solutions of a monodisperse sample of 90% hydrolysed poly (vinylalcohol) PvOH and for solutions of PvOH in short chain alcohol/water mixtures. The results are interpreted in terms of a ‘dynamic’ flowing volume and a ‘static’ partial molar volume for the macromolecule. Changes in the size of the dynamic and static volumes of the polymer in alcohol/water solvent mixtures are shown to correlate closely with reported changes in the degree of solvent structure. A tentative explanation of the role of solvent structure in the solution behaviour of the polymer is p

ISSN:0007-1641    

DOI:10.1002/pi.4980090405

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractAn enzyme digestion technique for obtaining the scatter from pectin molecules in solution is described and evaluated. Weight average molecular weights,w, calculated from the pectin scatter, are considerably higher than literature values obtained via sedimentation equilibrium experiments, but the present results are preferred. Limited comparison with a number average value,n, obtained osmometrically, suggests that pectins can be extremely poly disperse withw/n= 11, for example. The relationship of intrinsic viscosity to molecular weight is a complex function of composition.

ISSN:0007-1641    

DOI:10.1002/pi.4980090406

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe crystallisation kinetics of high molecular weight fractions of polyethylene oxide have been measured dilatometrically and also with a polarising light microscope. In general, marked deviations from the Avrami equation with exponent of 3.0 are observed which cannot alone be accounted for either in terms of rejection of low molecular weight molecules or secondary crystallisation by which crystal perfection occurs. Anomalies in nucleation, and the presence of induction periods, are present, which can account for the apparent low values of the Avrami exponent, i.e. 2.0.

ISSN:0007-1641    

DOI:10.1002/pi.4980090407

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractThe technological applications and the associated molecular mechanisms of various levels of orientation in polyester fibres are discussed. The inherent birefringence of these fibres is high and therefore the orientation is easily measurable, while their behaviour is very sensitive to small changes in orientation. In particular, practical properties such as strength, productivity and ease of bulking are very dependent on the spun yarn orientation before the drawing operation takes place, but for completely different reasons. Polyester fibres can be pretreated in terms of orientation in such a way that an extremely high spontaneous extension can be obtained, a property which can be used for bulking. It is shown that variations in low levels of orientation can have profound industrial implications.

ISSN:0007-1641    

DOI:10.1002/pi.4980090408

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractStudies have been made on gelatine gels containing inorganic salts and ionic surfactants, with the aim of learning about factors that influence the structural make‐up of hydrogels. Gel‐sol transition temperature,Tm, was studied by a micro capillary‐visco‐meter, gel‐elasticity,E, by applying unidirectional compression and gel‐hardness (rigidity),H, by using Röths micro penetrometer. An attempt was made to describe the results quantitatively. The equationlg Tm=k c+bwas found to fit the data on gelation and analogous equations proved to be valid for both theEvs.cand theHvs.crelations. This is true for the different chlorides in the whole concentration‐range studied, but for sulphates over a limited concentration range only. The specific effect of the latter reveals itself mostly in the changes ofTmandH. As ΔH was not altered significantly by the cosolutes used it is concluded that ΔS plays the essential role in the d

ISSN:0007-1641    

DOI:10.1002/pi.4980090409

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980090410

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY

摘要:

AbstractResults are given for the effects of four hydrocarbon diluents (benzene, toluene, ethylbenzene and cyclohexane) upon the rate of emulsion polymerisation of styrene at 50°C, upon the particle size of the resultant latex, and upon the intrinsic viscosity of the polymer produced. The aromatic diluents were found to have a much greater effect in reducing the rate of polymerisation than can be accounted for by mere dilution of the monomer. For these diluents, the rate of polymerisation is approximately third order in initial concentration of monomer in the oil phase as a whole. Cyclohexane is far less effective as a retarder of polymerisation, the rate being approximately first order in monomer concentration in the oil phase. Particle size determinations indicate that the reductions in rate are due primarily to a reduction in the rate of polymerisation at each locus, rather than to a reduction in the number of reaction loci. The intrinsic viscosity of the polymer produced tends to fall with the rate of polymerisation. These observations are consistent with the view that aromatic diluents cause severe retardation of polymerisation because they diminish the Trommsdorff ‘gel’ effect at the reaction loci. This view is in turn shown to be consistent with a reaction mechanism in which, in the case of styrene‐rich systems at least, the growing polymer particles do not attain equilibrium with the monomer dr

ISSN:0007-1641    

DOI:10.1002/pi.4980090411

出版商:John Wiley&Sons, Ltd    

年代:1977

数据来源: WILEY