ISSN:0272-8397    

DOI:10.1002/pc.750070502

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThe physicomechanical properties of phenolic composites containing a large amount of mineral fillers were enhanced through a chemical modification of the basic resin. Various phenolic compounds were first introduced in the condensation mixture leading to modified novolaks, but the final properties of the resulting composites were only slightly improved. Better results were obtained using an optimum content of epoxy‐novolak or melamine in the last stage of processing as confirmed by static and dynamic mechanical analysis. The new procedure introduced recently by Halpin and Sendeckyj for fitting fatigue models was applied to our particle‐filled material. The results confirm the reinforcement of the composite through the co‐reactivity of phenolic resins with the introduced species in the final curing

ISSN:0272-8397    

DOI:10.1002/pc.750070503

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThere is a growing commercial and academic interest in polymeric composites filled with short fibers and/or glass or mica flakes. Here, the properties depend strongly on the flow induced morphology and on the distribution of residual stresses. To optimize processing and properties, it is important to know both the melt rheology and the orientation of the dispersed phase. The industrial formulations are notoriously very complex. However, it is possible to understand, and sometimes predict, their behavior by a systematic comparison with simpler, better known systems, i.e., suspensions. This review concentrates on two main aspects of flow of polymer melts containing anisometric particles, namely yield phenomena and orientation.

ISSN:0272-8397    

DOI:10.1002/pc.750070504

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractUtilization of cone‐and‐plate and rotational parallel plate rheometry to characterize the rheological behavior of fiber‐filled polymer melts at low shear rates was evaluated. The effect of flow geometry and dimensions on the viscoelastic and viscometric functions was considered. Stress growth functions were found to be dependent on the dimensions of the flow channel. However, viscometric functions were not affected by the dimensions or the geometry of the flow channel. The initial state of orientation was found to be an important factor in determining the flow found to be an important factor in determining the flow behavior. Oscillatory shear tests yielded highly strain‐dependent loss and storage moduli even at very small strain amplitudes. However, the stress response was found to be sinusoidal in most cases, although the properties were strain de

ISSN:0272-8397    

DOI:10.1002/pc.750070505

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThe dynamic mechanical responses of rutile‐filled, chlorinated polyethylene (CPE) were studied as a function of temperature, of filler loading, and of filler surface condition. An objective was to establish the influence of matrix‐filler interactions on mechanical properties. Necessary information on potential interactions between matrix and filler was obtained from inverse gas chromatographic data, in the form of an acid‐base interaction parameter, Ω. The damping peak in filled CPE compounds was depressed by the pigment, as called for by theoretical models. The magnitude of the effect exceeded expectations, however, and clearly depended on the strength of interfacial interactions. These were consistent with the acid‐base ranking of CPE and the various rutiles, as given by Ω. It has been postulated that in the presence of acid‐base interactions, an immobilized layer of polymer in the vicinity of solid particles increases the effective particle dimension, thereby accounting for the observed variations in relative damping. Additional effects of matrix‐filler interaction were noted in the variation of storage moduli with loading and temperature. Again, the effects tend to be more pronounced when significant specific interactions between matrix and solid are operative. These observations point to the inadequacy of existing models as interpretative bases for dynamic mechanical properties in systems with significant specifie interactions among the

ISSN:0272-8397    

DOI:10.1002/pc.750070506

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThe characteristics of compounds of acrylonitrile‐buta‐diene‐styrene and high impact polystyrene resins, filled with carbon fibers, steel fibers, carbon black, and aluminum flakes have been investigated with special emphasis on electrical conductivity and flow behavior in a capillary rheometer. Compression and injection molded compounds were found to be highly electrically anisotropic. The components of the electrical conductivity tensor,K11,K22andK33, were measured, GenerallyK11, the flow direction conductivity, has the highest value and the thickness direction, andK33has the lowest. The injection molded parts were usually electrically heterogeneous with the conduetivities highest at the greatest distances from the gate. The results were interpreted in terms of particle orientation and distribution. Shear viscosities were measurable for all but the aluminum flake compounds which exhibited fluctuating pressure drops. The flow of these compounds through dies was investigated. Examination of material from the die entrance indicated streamline flow without entrance vortices. Sometimes high entrance concentration of particulates were observed especially for the aluminum flakes. Extrudates were found to contain oriented part

ISSN:0272-8397    

DOI:10.1002/pc.750070507

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractA wide angle x‐ray diffraction technique has been used to determine the orientation of mica flakes in composites. The mica used was a fine grade Phlogopite, and the polymers were polystyrene, polycarbonate and poly(vinyl chloride). Composite samples of varying mica contents and orientations were prepared. The x‐ray method can give the orientation distribution function of mica flakes across and parallel to the surface of the sample. From this function, an average orientation parameter was calculated. The results show that there is no orientation of mica across the surface of the sample (the x‐ray beam is normal to the surface), but that there is a strong orientation in a direction parallel to this surface, the average orientation parameter being strongly dependent upon the particle size of mica and mode of prepar

ISSN:0272-8397    

DOI:10.1002/pc.750070508

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractShort glass fiber reinforced polypropylene was employed in a study to determine the effect of molding and mold design variables on the distrubution of fibers and their orientations, and consequently, on the distributions of mechanical properties in the molded article. In this paper, a variety of experimental techniques were employed to evaluate the distributions of fibers and their orientations. Moreover, techniques were developed to evaluate the orientation and crystallization of the matrix. The results yield significant information regarding the development and control of both the microstructure and the properties of short fiber reinforced composites.

ISSN:0272-8397    

DOI:10.1002/pc.750070509

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractThe physical and mechanical properties of epoxy‐amine matrices can be improved by the use of additives known as epoxy fortifiers. The tensile strength of a typical aminecured epoxy increased from 82 MPa to 123 MPa, the tensile modulus form 2.5 GPa to 4.1 GPa, and the tensile test specimens also failed in a ductile fashion. The improvements in matrix properties translated into improved performance for filament‐wound and cloth‐reinforced composites. For example, the transverse moduli and compression strengths of carbon fiber/epoxy filament‐wound tubes and plates increased at least 20 percent with the addition of fortifiers, while the compression strength of glass cloth/epoxy laminates increased by up to 41

ISSN:0272-8397    

DOI:10.1002/pc.750070510

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY

摘要:

AbstractHardwood fibers of aspen in the form of chemithermo‐mechanical pulp (CTMP) have been used as reinforcement in linear low density polyethylene (LLDPE). The effect of composite treatment (immersion in boiling water, heat exposure at 105°C for seven days or at a temperature of −40°C) on resulting mechanical properties were evaluated. The grafted aspen CTMP composites showed by far the best results with regard to secant modulus, tensile strength, energy, and strain when compared to those of wood flour, mica or glass–fiber filled LLDPE, as well as to virgin LLDPE. Finally, the dimensional stability of CTMP aspen‐filled LLDPE composites immersed for four hours in boiling water was better than that of mica or glass–fiber f

ISSN:0272-8397    

DOI:10.1002/pc.750070511

出版商:Society of Plastics Engineers    

年代:1986

数据来源: WILEY