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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Properties Enhancement of Short-Glass-Fiber Reinforced
Thermoplastics by Sandwich Injection Molding Technique) ผู้เขียน: สมเจตน์ พัชรพันธ์, G?nter Mennig สื่อสิ่งพิมพ์:pdf AbstractThis article demonstrates the possibility of using sandwich injection molding in order to improve
the mechanical properties of short-glass-fiber-reinforced thermoplastic by investigating the effect of fiber
orientation, compared with conventional injection molding. The effects of short-glass-fiber content
within skin and core materials, in the present case PP, varying from 0 to 40 wt % were studied. The results
showed an increase in the maximum tensile stress and impact strength as the concentration of the shortglass-
fiber was increased. The mechanical properties of sandwich moldings were observed to be slightly
higher than conventional injection moldings, which is attributed to the higher fiber orientation and lesser
voids within the core layer. The effect of different processing types on the phase distribution of shortglass-
fibers showed no significant phase separation effects between sandwich and conventional injection
molding processes, except when using of sandwich injection process with different materials. The results
obtained by analyzing the fiber attrition inside the skin and core regions in the longitude direction of
tensile specimens showed that the degree of fiber degradation inside the skin layers were higher than the
core layers and there are only minor differences in fiber length inside skin regions observed between
sandwich and conventional injection molding processes, whilst this effect being more pronounced in the
core regions and for the higher fiber volume fraction. The theoretically calculated values of the ultimate
tensile stress (UTS) were found to be considerably higher than the experimental values. However, a more
realistic estimation of UTS can be achieved by using measured values for fiber length within skin and core
layers. |