Investigation into the mechanism of tack of rubbers

Abstract

The tack of cis‐polybutadiene was measured by means of a Skewis tackmeter, and the results, which showed considerable variability, could be represented by a double exponential cumulative distribution function of Gumbel. It was concluded that there exists a linear relationship between the applied forces (contact and break) and the time that these forces are applied in the tack test. The mechanism of tack is considered in terms of two distinct processes: (a) the development of a bond and (b) the strength of the bond thus formed. The latter is rationalized by applying Eyring's absolute rate theory. A simple equation is derived which predicts an inverse linear relation between the breaking time and breaking force, which is in agreement with the experiment. The theory also suggests that the area of actual interpenetration of polymer interfaces depends largely on the contact pressure, whereas the depth of penetration appears to depend to a similar degree on both contact pressure and contact time.

The Effects of Processing on Interply Bond Strength of Thermoplastic Composites

“…The mechanism governing the formation of interply bonds has been established as autohesion or self-diffusion [2]. The theories and destructive mechanical tests characterizing autohesive bond development in thermoplastic resins are well developed [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. However, few studies were focused on the interply strength development during formation of a fiber-reinforced thermoplastic laminate.…”

The effect of simple shear flow on the helix-coil transition of poly-L-lysine

“…15 Following the methodology of Coleman 16 and Bauer, 17 we let f(t) represent the average shear stress experienced by a PLL molecule. Since our system is dilute and Newtonian, the latter would be given by the product of the solution viscosity and the shear rate.…”