Investigations On P-aramid Short Fiber/P-aramid Pulp Rubber Matrix Composite

In this article p-aramid pulp(KevlarRâ—‹Engineered Elastomer,EE is the abbreviation) SBR1502 matrix composite and p-aramid short fiber(Sulfron3000Râ—‹) SBR1502 matrix composite were made by dry mixing .The effect of short fiber and pulp on the processing property of pure SBR and on that of carbon black/silica reinforced SBR was investigated by testing the Mooney viscosity of these composites of which the fiber content was different. At the same time, the effect of the different amount of short fiber and pulp on the composites'physical property such as hardness, tensile strength, elongation at break, trouser tear strength and the amount of Akron abrasion was also studied. Then the dispersing form of short fiber and pulp in pure SBR matrix composite and in carbon black/silica reinforced SBR matrix composite was researched by using fluori-microscope , the difference and similarity of the dispersing form was compared. The effect of adding carbon black and silica on the dispersing form of aramid was studied simultaneously. The rupture section and brittle-rupture of the tensile rupture composite was investigated by using SEM (Scanning Electron Microsope). The results show: when the amount is no more than 10phr, the effect of EE,Sulfron3000 on the processing viscosity of the composites and on the impulse load of the processing equipment is negligible, and was equal to the blank sample by and large. After adding EE, sulfron 3000 into theses composites, the hardness, trouser tear strength ,the amount of Akron abrasion of the composites before and after aging was linearly increased ;while the tensile strength and elongation at break decreased as a whole. With the increase of the dosage of fiber, tensile strength and elongation at break changed as followed: at first ,they decreased ;then increased to a peak point and decreased again. The disperse and form of the pulp of which surface was fibrillated in matrix differed from that of the fiber of which surface was not fibrillated. The critical length to diameter ratio(L/D) of pulp was lower than that of short fiber when the composites were rupture-destroyed, while the pulp had better interface adhesion property with matrix than short fiber. The viscosity and shear stress of the compound increased by adding carbon black and silica into the composites. The short fiber, pulp was mixing more equably ;the orientation was higher ;the cleavage and rupture was increased and the (L/D) of aramid in the composites was lowered after carbon black and silica was added to the compound. The pre-dispersing short fiber and pulp made the dispersion of aramid easier; but when the dosage was higher, the auxiliary ingredients of pre-dispersing short fiber and pulp must be took into account when formula was designed.