A PHYSICAL ADHESIVE FACTOR BETWEEN POLYMER AND FILLER WHICH AFFECTS TENSILE-STRENGTH OF FIBER REINFORCED COMPOSITE-MATERIALS

The effects of shrinkage in injection molding on the tensile strength of fiber reinforced composite plastics have been investigated. Tetrafluoroethylene copolymer (ETFE) and polyethylene (PE) etc. were reinforced by glass fibers, and polyamid (PA12) and polyethylene (PE) were renforced with glass fibers and aramid fibers, respectively. The ratio of tensile strength of fiber reinforced composite materials to that of matrix polymer tends to become higher with increasing mold shrinkage in spite of the small adhesion difference between filler and polymer. The physical adhesion of the matrix materials to fibers is improved with increasing mold shrinkage of base polymer. These results show that the mold shrinkage is one of the factors which affect the tensile strength of filler reinforced injection moldings.