摘要:

AbstractA new method of applying small (<3 percent) and uniform compressive strains to organic fibers by shrinkage of a surrounding polymer matrix is reported. The results of this matrix‐induced compression on the morphology and tensile properties of Kevlar fiber are examine

ISSN:0272-8397    

DOI:10.1002/pc.750030202

出版商:Society of Plastics Engineers, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractA study was undertaken to determine the feasibility of using dielectric analysis as a means of monitoring and controlling cure of large closures during autoclave molding. In dielectric analysis, the dissipation factor (DF) and capacitance (C) of the sample are continuously monitored as a function of time, temperature, and frequency. Dissipation factor profiles were established for the suppliers' recommended cure cycle and for modified cure cycles, Good reproducibility was obtained in dissipation factor profiles on subsequent scaling up to production size (7 ft · 20 ft) autoclaves. Good correlation was also observed during production runs of fullscale closures. The effects of cure variables on the dissipation factor profiles and on the mechanical properties of the prepared laminates were analyzed for extent of correlation. Results of this study show: (1) dielectric analysis can be used to monitor autoclave cure of composites, and (2) within limits, process control may be feasible

ISSN:0272-8397    

DOI:10.1002/pc.750030203

出版商:Society of Plastics Engineers, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe common degrading effect of glass beads on the static fracture energy and the fatigue crack propagation response in nylon 6 materials is examined by conducting fracture mechanics tests and by considering the progress of cracks through the composites. The scanning electron micrographs indicate that the cracks travel through regions of polymer matrix and also along the interfaces between polymer and glass beads. It is demonstrated that, although fracture of the polymer regions requires considerable energy, cracking of the interfaces usually absorbs very little. Thus, the crack propagation is preferably concentrated on these microstructural regions, which is the cause of the decrease in fracture energy and increase in fatigue crack growth rate with increasing amount of glass spheres in the composite. Partial properties of the matrix and the interface are introduced in order to describe the fracture behavior and to improve the understanding of the gross fracture processes. The combination of these partial properties with the volume fraction of filler and certain geometrical factors by a modified rule of mixture leads to critical values for the failure of the composites, which are in reasonable accord with the measured fatigue and fracture data.

ISSN:0272-8397    

DOI:10.1002/pc.750030204

出版商:Society of Plastics Engineers, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractA gripping system has been developed to test uniaxial, 0° orientation PMR 15/Celion 6000 composites at elevated temperatures. The method involves compression of grit‐blasted laminate between grit‐blasted metal to give a non‐slipping interface for load transfer. Tensile testing at both 316°C and room temperature indicated that deformation was elastic to fracture and that the variation in tensile properties for one laminate is the same as that for several panels. In addition, the tensile properties for uniaxial PMR 15/Celion 6000 are identical at 316°C and room temperature. For nominally 51 volume percent fiber, the elastic modulus is 119.6 GPa, the fracture stress is 1370 MPa, and the strain to fracture is about 1.15 percent. In addition, data are presented which indicate that the gripping system can be used for long term, elevated temperature testing of composite m

ISSN:0272-8397    

DOI:10.1002/pc.750030205

出版商:Society of Plastics Engineers, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractCeramic particles were sedimented in methyl methacrylate, which was then polymerized by exposre to γ‐rays. After annealing, specimens were cut and tested, and the ceramic content determined by ashing. Diamond indentation hardness was found to increase monotonically with increase in ceramic content. In contrast, both Young's modulus and, more markedly, flexural strength were found to give optimum (peak) values for a content of lithium aluminum silicate near 80 wt‐percent. The higher silicate contents were reached with use of a silane coupling agent and by centrifuging, prior to polymerization. Examination of fracture surfaces by scanning electron microscopy indicated that the decrease in mechanical properties was due to the presence of voids in the polymeric matrix. It is suggested that void formation becomes serious when ceramic particles are initially too close‐packed to respond to conraction, during polymerization, by shifting closer together. Consistent with this suggestion, both void formation and peaking in strength can be prevented by continuously centrifuging the composite throughout the polymerization re

ISSN:0272-8397    

DOI:10.1002/pc.750030206

出版商:Society of Plastics Engineers, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractPolypropylene reinforced with glass fiber (28 percent by weight) was injection molded under different processing conditions. The influence of injection‐molding parameters such as pressure, injection speed, and injection temperature on the morphology and mechanical properties was studied using standard techniques, viz. polarizing microscope, scanning electron microscope, and Instron Universal testing machine. The observed mechanical properties were explained in terms of skin‐core‐morphology, transcrystallinity, fiber orientation and void volume. This study attempts to correlate processing conditions with morphology and mechanical properties. Such a study would help in optimizing processing conditions to give composites with desired prope

ISSN:0272-8397    

DOI:10.1002/pc.750030207

出版商:Society of Plastics Engineers, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractA series of melt‐processible fluoropolymer compounds including ethylene‐tetrafluoroethylene (ETFE), poly(vinylidene fluoride) (PVF2), ethylene‐chlorotrifluoroethylene copolymer (ECTFE), perfluoroalkoxy modified tetrafluoroethylene (PFA), and fluorinated ethylene‐propylene copolymer (FEP) containing reinforcing glass fiber, milled glass fiber, carbon fiber, minerals, poly(tetrafluoroethylene) (PTFE) lubricant powder, graphite powder and MoS2were prepared and characterized. The mechanical, physical, thermal, and tribiological properties of these composites were compared and ranked for suitability in various applications. These composites represent the first comprehensive evaluation of reinforced and filled meltprocessible fluoropolymer com

ISSN:0272-8397    

DOI:10.1002/pc.750030208

出版商:Society of Plastics Engineers, Inc.    

年代:1982

数据来源: WILEY

ISSN:0272-8397    

DOI:10.1002/pc.750030201

出版商:Society of Plastics Engineers, Inc.    

年代:1982

数据来源: WILEY