Elastomeric polyurethanes reinforced with aramid fibers

Abstract

SynopsisThermoplastic polyurethane is a relatively new development in the elastomers field, combining elastomeric behavior with thermoplastic processing characteristics. Thus, high production rates and reduced scrap can be achieved but, increased versatility for the incorporation of additives is also possible. In this work, thermoplastic polyurethane matrices were prepared and Kevlar pulp w a s dispersed as a reinforcing agent. Since good dispersion and appropriate filler volume fraction are critical factors for a reinforcing effect, special attention was paid to the optimization of these parameters. Thermoplastic polyurethanes were prepared by mixing a low melting polyol with a low melting diisocyanate and the subsequent addition of small amounts of a chain extender, namely, a low molecular weight diol such as 1,4 butanediol. The Kevlar pulp was added under stimng either in the polyol or the diisocyanate melt. This incorporation technique allows the dispersion of small fiber percentages. Thus, calendering of the materials prepared was also performed and additional fibers were incorporated. Changes in the properties of the specimens prepared as a function of the filler volume fraction and the dispersion technique were determined, taking into consideration the possibilities of chemical interaction between fibers and matrix.

Tensile Properties of Polymerization-Filled Kevlar Pulp/Polyethylene Composites

“…Moduli of short fiber composites are affected by fiber aspect ratio 31-37,54-55 , fiber-matrix interface adhesion [15][16][17][18][19]56 , fiber concentration 31-37,54-55 and many more 30,[35][36][37][40][41] . With a limited number of data collected, we do not explore the relationship between these factors.…”

“…Kevlar fiber is widely used in the aeronautical industry as thermoset composites 14 . As far as thermoplastic composites are concerned, the application of Kevlar fiber is limited, mainly due to the poor adhesion of these fibers with most thermoplastic resins [15][16][17] . Saikrasun et al 18 studied Kevlar reinforced polyolefinbased thermoplastic elastomers.…”

Polyethylene-Kevlar Composite Foams I: Morphology

“…Kevlar fibers are widely used in the aeronautical industry as epoxy composites (10) . As far as thermoplastic composites are concerned, the application of Kevlar fibers is limited due to poor adhesion between these fibers and polymers (11)(12)(13)(14) . Wang et al (15,16) adopted the PFC technique for fiber composites, similarly as Howard (2,3) and others did for inorganic filler composites, to improve fiber-matrix interaction in polyolefin composites.…”

Mechanical properties of epoxies reinforced with chloride-treated aramid fibers

“…In a subsequent stage, postcuring took mation about the interactions between the chloplace at 150ЊC for 1 h. ride-treated aramid fibers and the epoxy resin and, more specifically, to compare the behavior of the epoxy matrix composites with those composed Treatment and Characterization of Reinforcement of unsaturated polyester, polyethylene, and polyMethacryloyl chloride (Purum, Fluka AG) and urethane matrix, which were studied in the carbon tetrachloride (CCl 4 , chemically pure, Malpast. [22][23][24] linckrodt Chemical Works) were used. The acid chloride was dissolved in CCl 4 (10/90 v/v solu-EXPERIMENTAL tion) in order to prepare a less reactive means for treatment of the aramid fibers.…”