Transcrystallized interphase in thermoplastic composites

Optimization of the crystallinity of polypropylene/submicronic-talc composites: The role of filler ratio and cooling rate

“…In the case of composites with lamellar fillers, this phenomenon is enhanced by to the so-called shear-amplification effect [58]. The shear-induced nucleation can compete with filler-induced nucleation [59] and may even prevail on it [33]. In the present study, the thermal treatment of the samples at T = 210°C for 5 min prior to the DSC crystallization experiments was carried out in order to erase any shear-induced chain orientation due to processing.…”

Future requirements in the characterization of continuous fiber-reinforced polymeric composites (IUPAC Technical Report)

“…In contrast to transcrystallinity in quiescent crystallization, the application of stress at the interface between a fiber and polymer melt results in the crystallization on rownuclei around the fiber. This effect is caused by strain-induced nucleation via some self-nucleation mechanism and is independent of the type of fiber and less dependent on the temperature of crystallization [20,21]. Axial stresses arise also during cooling of two materials with large differences in thermal expansion coefficients.…”

The influence of chain defects on the crystallisation behaviour of isotactic polypropylene

“…However, its contribution to the temperature dependence of G is negligible relative to that of the transport term {U * /[R(T -.T 0 )]} and the nucleation free energy term {K g /(T·/T)}, respectively [42]. The expression for the secondary nucleation constant is the following Equation (16): (16) In this equation " u and " e are the interfacial lateral free energy and the interfacial surface free energy, respectively. The interfacial free energies defined Meer et al -eXPRESS Polymer Letters Vol.9, No.3 (2015) here are related to nucleation (like all other terms) and cannot a priori be identified with characteristics of the mature crystallites that subsequently develop.…”

“…The mechanical load can be introduced by pulling a fibre through an undercooled melt at a certain temperature T pull . The shear stress generated by fibre pulling produces row nuclei consisting of the !-phase that induce the growth of a cylindritic growth front [13][14][15][16][17][18][19]37]. These row nuclei surround the fibre in a cylindritic fashion thus the growth front is cylindrical and proceeds in the radial direction.…”

“…Shear stress generated for example by pulling a fibre through an undercooled melt produces row nuclei consisting of the !-phase, inducing the growth of a cylindrical growth front consisting of the "-phase. Several studies [14][15][16][17][18][19] were dealing with parameters that influence the formation of such "-cylindrites, like the temperature of pulling (T pull ), crystallization temperature (T c ), time of pulling (t pull ), speed of fibre pull (v pull ), etc. The conclusion from these studies was that samples rich in "-phase are formed when T !"…”