摘要:

AbstractWe discuss some theoretical aspects of interfacial and emulsifying activity of block copolymers A‐B in incompatible blends of homopolymers A and B. We predict the reduction in interfacial tension due to equilibrium adsorption of copolymers at the interface. It is shown that for an appropriate choice of block copolymer composition and molecular weight a very low interfacial tension can be achieved. This suggests a possible existence of a thermodynamically controlled stable droplet phase in which minority homopolymer particles protected by an interfacial film are suspended in a majority homopolymer matrix. The size distribution of the droplets depends on the rigidity and spontaneous radius of curvature of the interfacial film which, as we show, can be controlled by molecular parameters of copolymer

ISSN:0258-0322    

DOI:10.1002/masy.19880160103

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractWe investigate the mechanics of formation of polymer blends both from the view of (i) the technology and flow characteristics in batch and continuous compounding machinery as well as from (ii) the mechanistic perspective of the formation and evolution of dispersed phases. Special attention is given to internal mixers and to intermeshing co‐rotating twin screw extruders. The role of interfacial tension and viscosity ratio in affecting phase morphology is described. We also discuss the development of polymer chain orientation in the different components of an immiscible polymer blend during processin

ISSN:0258-0322    

DOI:10.1002/masy.19880160104

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractIt will be shown how a combination of techniques allows to gain a rather precise idea of the (un)miscibility situation in polymer blends at different size scales (i.e. from ca.20 A up to lμ); typical examples include simultaneous use of TEM, SEM, NRET and ss. NMR.On these bases, interesting blends have been studied and tailored, in which both morphology and interfacial adhesion have been controlled (in particular by the use of diblock copolymers) to provide for a better spectrum of properties. A number of situations will be described, implying commodity and engineering polymers, but also different types of fillers; their optimization has led to interesting applications in the field of better emulsion dispersions, very high impact resins, economical engineering plastics, controlled migration, filled materials,

ISSN:0258-0322    

DOI:10.1002/masy.19880160105

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractTechnical and economic considerations have given polymer blends a major share in the increasing sales of plastics. This applies both to general‐purpose and to the higher value‐added materials. Thus it is scarcely surprising that almost all polymer manufacturers have now developed comprehensive ranges of blends having particular property profiles. The principal types of blends currently available are described.The variety of products already developed should not be allowed to obscure the fact that certain conceivable and highly attractive property combinations have not so far been realized. If progress is to be made in this area, interdisciplinary cooperation between chemists and physicists in the fields of polymer chemistry, polymer physics and materials science is essent

ISSN:0258-0322    

DOI:10.1002/masy.19880160106

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractApplication of digital image analysis (DIA) to polymer blends morphology is discussed with examples. Various operations in DIA including two‐dimensional Fourier transformation (2DFT), intensity distribution, recursive region extraction, etc. are applied to morphology of polymer blends due to spinodal decomposition (SD), nucleation 6 growth (NG), and eutectic solidification (ES). Merits and drawbacks of DIA to study polymer blends morphology are discussed and the possibility of future development is presente

ISSN:0258-0322    

DOI:10.1002/masy.19880160107

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractBinary interaction parameters, Xijhave been determined for the monomer pairs, styrene‐acrylonitrile and methyl methacrylate‐acrylonitrile from phase separation measurements in homopolymer‐copolymer blends. These have been used to predict regions of miscibility in different blends of statistical copolymers where the components were (a) poly(styrene‐co‐acrylonitrile), (b) poly(styrene‐co‐methylmethacrylate) and (c) poly(methylmethacrylate‐co‐acrylonitrile). Agreement between prediction and experiment was good in all cases. Extensive miscibility ranges were obtained for blends of (a) with (b), and (a) with (c), but combinations of (b) with (

ISSN:0258-0322    

DOI:10.1002/masy.19880160108

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractVarious morphologies can be realized via processing of incompatible polymer blends such as droplets or fibers in a matrix and stratified or cocontinuous structures as is shown for the model system polyethylene/polystyrene The structures induced are usually intrinsically unstable. Modelling of extrusion processes and continuous mixers yields expressions for the shear rate and shear stress but also for the limited residence time and the number of reorientations. These results could be combined with detailed knowledge of respectively distributive and dispersive mixing processes to predict the development of various morphologies as a function of time. Control of morphology is of utmost importance. In the case of droplets in a matrix, usually encountered in toughening of glassy polymers, the use of compatibilizers and/or reactions at the interphases is utilized. However, in designing specific morphologies i.e. structured polymer blends, fixation of intermediate morphologies before final processing is a prerequisite. Some preliminary results will be presented.

ISSN:0258-0322    

DOI:10.1002/masy.19880160109

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA key to the success of plastics in the automotive industry is the use of alloying technology which, relatively quickly leads to tailor‐made materials at interesting cost‐performance ratios. In this paper an overview of the various criteria used in the laboratory in testing alloys for auto parts is given and an attempt is made to point out the most significant determinations. The results obtained comparing the materials indicate how inadequate the standard methods are in describing the real behaviour of the items under operating conditions. Nonetheless, just making some modifications in test geometry leads to a sufficiently realistic correspondance between laboratory test data and item performa

ISSN:0258-0322    

DOI:10.1002/masy.19880160110

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractResults of an investigation on the morphology, structure, isothermal crystallization, thermal behaviour and miscibility of poly(ethylene oxide) (PEO) based binary blends are reported. In particular poly(vinyl acetate)(PVAc), poly(methyl methacrylate) (PMMA) at different tacticity and poly(ethyl methacrylate) (PEMA) were added to PEO.It was found that with the only exception of isotactic poly(methyl methacrylate) (IPMMA), the addition of the above cited components causes a depression in both the spherulite growth rate and the overall kinetic rate constant. The experimental G and Kn were analyzed by means of the latest kinetic theory in order to determine the influence of composition on the process of surface secondary nucleation. The optical microscopy of thin films of the sample revealed that the blends crystallized with volume filling crystals at least up to 50/50 blend composition. The small angle X‐ray scattering curves were analyzed using a recently developed methodology. The structural properties of the blends were attributed to the presence of the non crystallizable material in the interlamellar or interfibrillar regions of PEO. From the glass transition temperature it has been deduced that an homogeneous amorphous phase is present for all the blends except for the PEO/IPMMA amorphous system. For the system PEO/atactic poly(methyl methacrylate) (APMMA) the miscibility was also predicted by theoretical approache

ISSN:0258-0322    

DOI:10.1002/masy.19880160111

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe properties of polymer alloys are strongly dependent on their phase morphologies. Usually, the phase dispersion and domain sizes are affected by the process and can be influenced and stabilized only “extrinsically” by dispersants and emulsifiers. But, there are some examples of alloys with phase morphologies which are “intrinsically” determined and thus independently of the processing conditions. This aspect of phase determining factors is discussed using four principally different examples of polymer

ISSN:0258-0322    

DOI:10.1002/masy.19880160112

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY