The effects of molecular weight (MW) and MW distribution on the maximum tensile properties of polyethylene (PE), achieved by the uniaxial drawing of solution-grown crystal (SGC) mats, were studied. The linear-PE samples used had wide ranges of weight-average (M-w = 1.5-65 x 10(5)) and number-average MWs (M-n = 2.0-100 x 10(4)), and MW distribution (M-w/M-n 2.3-14). The SGC mats of these samples were drawn by a two-stage draw technique, which consists of a first-stage solid-state coextrusion followed by a second-stage tensile drawing, under controlled conditions. The optimum temperature for the second-stage draw and the resulting maximum-achieved total draw ratio (DRt) increased with the MW. For a given PE, both the tensile modulus and strength increased steadily with the DRt and reached constant values that are characteristic for the sample MW The tensile modulus at a given DRt was not significantly affected by the MW in the lower DRt range (DRt < 50). However, both the maximum achieved tensile modulus (80-225 GPa) and strength (1.0-5.6 GPa), as well as those at higher DR(t)s > 50, were significantly higher for a higher MW Although the maximum modulus reached 225 +/- 5 for M-n >= 4 x 10(5), the maximum strength continued to increase with M-n even for M-n > 4 x 10(5), showing that strength is more strongly dependent on the M-n, even at higher Mo. Furthermore, it was found that each of the maximum tensile modulus and strength achieved could be expressed by a unique function of the Mn, independently of the wide variations of the sample MW and MW distribution. These results provide an experimental evidence that the M-n has a crucial effect on the tensile properties of extremely drawn and chain-extended PE fibers, because the structural continuity along the fiber axis increases with the chain length, and hence with the M-n. (c) 2005 Wiley Periodicals, Inc.