A Study of Fiber Breakage during Compounding in a Buss Kneader

Abstract

International audienceThis paper is devoted to the study of fiber breakage during compounding with a polyamide matrix in a Buss kneader. Results showed a drastic decrease of glass fiber length during compounding, typically from 3500 to 350 mu m. Fiber breakage depended on processing conditions: it increased with screw speed, but the effect of feed rate was less clear. Fiber breakage increased also with the severity of the screw profile. Characterizations of fiber length evolution along the screw profile have also been performed after dead-stop experiments. Generally speaking, fiber length evolution can be described using a modified Shon-Liu-White model, in which either the number of turns or the specific energy is considered

Influence of Extrusion Conditions on Fiber Breakage along the Screw Profile during Twin Screw Compounding of Glass Fiber-reinforced PA

“…The materials are the same as in the previous studies (Inceoglu et al, 2011;Ville et al, 2012). The matrix is a Polyamide-12 (PA12), kindly supplied by Arkema (France).…”

“…In this so-called modified model, either the number of turns or the specific energy is taken into account, even though specific energy seems to be more appropriate to calculate fiber breakage. The results predicted from the model highlight the effect of mixing conditions (screw speed and feed rate) and of the screw profile on fiber length distribution (Inceoglu et al, 2011;Ville et al, 2012).…”

“…These properties strongly depend on fiber properties (mainly tensile strength), on adhesion between fiber and matrix (Lee and Jang, 1997) and on fibers macrostructure i. e. the fiber orientation and size distribution induced during processing (Fu et al, 1999). Although high aspect ratios (long fibers) would be necessary to achieve good mechanical properties (Gupta et al, 1989), severe fiber breakage often occurs in compounding processes such as internal mixers (Fisa, 1985;Shimizu et al, 1997), twin screw extruders (Von Turkovich and Erwin, 1983;Gupta et al, 1989;Wall, 1989;Inceoglu et al, 2011) or Buss co-kneaders (Shon andWhite, 1999, Shon et al 2005;Ville et al, 2012). In the literature, many studies were devoted to the investigation of the extent of fiber breakage and the effect of processing parameters on fiber length after compounding processes.…”

“…The effect of processing parameters on fiber breakage was recently investigated for glass fiber reinforced Polyamide 12 compounded using an internal mixer, two different twin screw extruders (Inceoglu et al, 2011) and a Buss co-kneader (Ville et al, 2012). Results have shown a substantial fiber breakage that occurred at the early stage of mixing for all these compounding processes.…”

Relationship between screw structure and properties of recycled glass fiber reinforced flame retardant nylon 46

“…When a ber reinforced composite was prepared by a different processing machine, the bers suffered because of the varied breakage caused by those machines. Ville et al 17 studied ber breakage during compounding with a polyamide matrix in a Buss kneader. They found that the composite mixed with a Buss kneader had shorter average ber length than that one mixed with a twin screw extruder.…”