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Injection molding higher performance reinforced plastic composites
Author(s) -
Rosato D. V.
Publication year - 1996
Publication title -
journal of vinyl and additive technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 1083-5601
DOI - 10.1002/vnl.10128
Subject(s) - materials science , composite material , polypropylene , molding (decorative) , glass fiber , compression molding , mold , composite number , fiber , creep , thermal stability , physics , quantum mechanics
Conventional screw plasticizing injection molding machines (IMM) have been used to mold over 50 wt% of all reinforced plastics (RP) composite processed (1–9). Principal reinforcement used is E‐glass of short glass fibers (SGF) with thermoplastics (TP) such as nylon (PA) and polypropylene (PP) (each over 25 wt% of total). Fiber lengths are usually limited to being milled to 1 mm (0.04 in); average length in molded parts are 0.3 mm (0.01 in) to 0.5mm (0.02 in); Long glass fibers (LGF) would be more desirable in obtaining better performances such as higher strength, stiffness, creep resistance, fatigue resistance and improvements in dimensional stability and thermal properties. However, fibers will degrade in length during conventional molding resulting in less efficient use of reinforcements. LGFs can start at 10 mm (0.4 in) and after IM can be in the order of at least 5 mm (0.2 in); longer fibers are also used. Special fiber impregnation techniques will permit successfully molding LGFs (1–21).