Reptation Time, Temperature, and Cosurfactant Effects on the Molecular Interdiffusion Rate during Polystyrene Latex Film Formation

Abstract

The interdiffusion of polymer chains during film formation from direct mini-emulsified deuterated and protonated polystyrenes (DPS = mol wt 150 000 and 185 000; HPS = mol wt 150 000 and 200 000) was characterized by small-angle neutron scattering (SANS) and tensile strength measurements. Films containing 6 mol % deuterated particles were annealed at several temperatures above Tg for various periods of time. The average interpenetration depth of deuterated polystyrene chains depended on the one-fourth power of the annealing time up to the reptation time, r, shifting to the one-half power after the reptation time. The center of mass diffusion coefficients from the SANS data were 2.4 X 10-16 cm2/s for Mn = 150 000 and 1.5 X 10-16 cm2/s for Mn = 185 000 at an annealing temperature of 135 °C. The diffusion activation energies of the present system were 52 ± 4 kcal/mol for the temperature range 125 < T < 155 °C. Full tensile strength was achieved at a penetration depth of 90-100 A, which is comparable to 0.81 times the radius of gyration of the whole polystyrene chain (86 A for Af" = 150 000) predicted theoretically. Finally, latex samples containing 1.5 wt % cosurfactants showed a faster interdiffusion rate especially at t > r and a smaller activation energy than the corresponding pure latex sample.

Fracture energy–fracture stress relationship for weak polymer–polymer interfaces

“…T bulk g are independent of M w and polydispersity ( [17,18], this work). These values of E a (s) are close to the values of Values of E a calculated from the experiments on lateral force microscopy [23,24], secondary ion mass spectroscopy [21], small-angle neutron scattering [20], modified n.m.r. field-gradient technique [19], lap-shear joint method [17,18,25], lap-shear joint and double cantilever beam methods [26].…”

“…In Table 1 are compared the values of E a (G) and E a (s) calculated above with the values of E a for several PSs available in the literature [17][18][19][20][21][22][23][24][25][26]. These E a values were calculated from the mechanical properties (s, G, lateral force F lat ) or from the diffusion coefficient D. For their calculation, three kinds of plots were employed: (i) the Arrhenius plot lnðs; G or DÞK 1=T, (ii) ln a T ðs or F lat Þ K1=T given by the classical principle of time-temperature superposition [Eq.…”

The kinetics of crystallization of poly(ε-caprolactone) measured by FTIR spectroscopy

“…Two diffusion mechanisms and the time dependence of segmental mobility are important in the reptation theory [17,18] and have been observed in self-diffusion studies using deuterated polymers [19,20] and computer modelling of polymer chains diffusing [21]; these are a dependence of diffusion distance on time, i.e., t and on the square root of time, i.e., t 1/2 . In diffusion over distances greater than the tube diameter, the displacement of the segments is constrained by entanglements and the process is that of large number of segments reptating.…”

Crosslinking of isocyanate functional acrylic latex with telechelic polybutadiene. III. Application of a diffusion model

“…The self-diffusion coeffiweight ratio or ¢ 3.0 mole ratio) were the PMBT cients of polystyrene at several temperatures have particles fully covered by the PBD-NH 2 . Thus, in been compared, 5 as shown in Table VI. Similar rethe present PSBT160/PBD-NH 2 system, only the sults were found for the deuterated polystyrene/ curve where NH 2 /TMI equals 2.78 is close to full protonated polystyrene system.…”