Transcrystallization of poly(l-lactic acid) on the surface of reduced graphene oxide fibers

Transcrystalline layer could form between rGOF and PLLA. The good nucleating ability of rGOF could be quantitatively characterized based on the theories of heterogeneous nucleation and crystal growth rate.

The Effect of Transcrystalline Interface on the Mechanical Properties of Polyethylene / Polyethylene Composites

The effect of the transcrystalline layer on the longitudinal properties of unidirectional polyethylene/polyethylene (PE/PE) composites was studied. Two sets of PE/PE composites were prepared by quenching and by isothermal crystallisation, respectively, using a wide range of fibre volume fractions. Quenching and isothermal crystallisation were expected, respectively, to prevent or to induce generation of a highly ordered transcrystalline layer. The experimental results showed that isothermal crystallisation produced a substantial positive effect on both the longitudinal strength and modulus, which was attributed to transcrystallinity.

Interphase with Lamellar Interlocking and Amorphous Adherent – a Model to Explain Effects of Transcrystallinity

An interphase model emphasising the lamellar architecture and the role of the amorphous phase is proposed to explain possible effects of the transcrystalline layer in composites consisting of semicrystalline polymer and fibres acting heterogeneous nucleants therein. Based on this model biased findings reported on the effects of transcrystallinity can be rationalised.

Thermal Expansion of Transcrystalline Strips

The results of a direct measurement of the longitudinal thermal expansion coefficient of an isolated transcrystalline layer are reported below for a nylon 66 transcrystalline strip grown on a Kevlar 29 aramid fibre. It is shown that the expansivity of the transcrystalline layer is more than an order of magnitude smaller than that of the bulk crystallized matrix. It is hypothesized that the transcrystalline layer relieves thermal stresses in composite materials by matching the expansivities of the constituents.

Effects of Glass and Carbon Fiber on Nylon 6,6 Crystallization

ABSTRACTThe effects of addition of glass fiber and HMS4 carbon fiber on the crystallization of nylon 6,6 has been investigated using DSC and polarized optical Microscopy (POM). DSC observations indicate that HMS4 fiber lowers the supercooling required to initiate crystallization. A transcrystalline layer is also observed in the near-fiber region of carbon fiber-reinforced composites after DSC. The presence of transcrystallinity and the earlier onset of crystallization for this composite are due to heterogeneous nucleation on carbon fiber surfaces. DSC Measurements of nylon 6,6 with glass fibers show supercoolings similar to those of neat nylon 6,6. Transcrystallinity is also absent in the glass-reinforced composites. These glass fibers appear to be weak nucleation catalysts. Different transcrystalline layer thickness is found to be influenced by thermal processing condition. In addition to transcrystallinity, the HMS4 carbon fiber also influences the bulk morphology of the nylon 6,6.