摘要:

AbstractThe effect of deformation history on the morphology and properties of liquid crystalline polymers (LCP) blended with polycarbonate resin was assessed. The addition of an immiscible LCP phase was found to improve the melt processability of the host thermoplastic polymer. In addition, by employing a suitable deformation history, the LCP phase may be elongated and oriented such that a microfibrillar morphology can be retained in the solid state.

ISSN:0032-3888    

DOI:10.1002/pen.760290902

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractPoly(vinyl chloride), PVC, is shown to be miscible with an α‐methyl styrene/acrylonitrile copolymer, αMSAN, containing 30 percent AN by weight using differential scanning calorimetry for blends prepared by several methods. Melt blending gave singleTgmixtures; whereas, solution techniques gave results that depended on the solvent choice and the manner in which it was removed. These blends do not phase separate on heating prior to significant PVC decomposition (∼250°C) in contrast to PVC/SAN blends which have much lower cloud points. Repulsion between α‐methyl styrene and acrylonitrile units in the copolymer is the principal cause for miscibility of this system as shown by an analysis based on a binary interaction model using calorimetry data for low molecular weight liquid analog

ISSN:0032-3888    

DOI:10.1002/pen.760290903

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractWe investigated the miscibility of polybutadienes with butadiene‐styrene copolymers of varying styrene content. The methods of optical microscopy, differential scanning calorimetry, and small angle light scattering (SALS) were used. All polymers/copolymers used in this study have equivalent butadiene microstructures. Copolymers with high styrene levels are immiscible with polybutadiene. The tendency to miscibility increases with decreasing styrene content. An upper critical solution temperature is observed with the 23 percent styrene copolyme

ISSN:0032-3888    

DOI:10.1002/pen.760290904

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractThe deformation of purely elastic spheres in steady and unsteady elongational flow has been studied. Experiments were carried out in a four roller apparatus (steady elongational flow) and in the time dependent elongational flow of a converging channel. The existing theory which gives a first order approximation of the deformation of elastic spheres is extended to the non‐steady elongational flow in the cone. Both in steady and unsteady elongational flow, the theory describes the deformation of the spheres satisfactorily and under certain conditions even for higher deformations than expecte

ISSN:0032-3888    

DOI:10.1002/pen.760290905

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractMechanical and rheological properties of blends of a thermotropic liquid crystalline polyester with a polycarbonate have been investigated. The blends are fibrillar in character and exhibit great hardness and toughness due to high degree of molecular orientation which develops during the melt blending and processing steps. Increases of the Young modulus by 100 percent are observed for blends containing only 10 percent of liquid crystalline polymer, LCP. Time‐dependent behavior of the blends was investigated by performing solid state relaxation measurements and the relaxation modulus was also found to increase by the addition of LCP. The effect is relatively small in the glassy zone of viscoelastic response, but increases through the transition and viscous flow regions. The melt viscosity of the polycarbonate is slightly shear thinning whereas that of the unblended LCP increases rapidly with decreasing shear rate at low shear rate. This suggests the presence of yield stresses as confirmed by measurements on the Rheometics RSR in the stress sweep mode. The melt viscosity of the blends was found to be similar to that of the unblended polycarbonate, but more shear‐thinning and less viscous. Preliminary results of scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) are also presen

ISSN:0032-3888    

DOI:10.1002/pen.760290906

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractA linear equation is proposed to quantify the glass transition behavior of miscible polymer blends in terms of the polymer‐polymer interaction density parameter whose values are obtainable from the melting point depression method. This practical model is successfully applied to four series of binary polyblends containing poly(hydroxy ether) of biphenol A, poly(vinyl chloride), poly(vinylidene fluoride), and poly(2,4‐dimethyl‐1,4‐phenylene oxide) as the common components. Each of these groups of polymer systems exhibits a distinct type of intermolecular interaction that can be characterized by the two coefficients of the model equation. In connection with the present analysis, three novel expressions are introduced for describing the glass transition temperature—composition relations of the polymer systems of

ISSN:0032-3888    

DOI:10.1002/pen.760290907

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760290901

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY