Abstract
Studies were conducted on the effects of shear rate, viscosity ratio and liquid crystalline polymer (LCP) content on the morphological and mechanical properties of polycarbonate (PC) and LCP blends. The LCP (LC5000) used was a thermotropic liquid crystalline polymer consisting of 80/20 of parahydroxybenzoic acid and poly(ethylene terephthalate) (PHB/PET). The viscosity ratio (viscosity of LCP: viscosity of matrix) was varied by using two processing temperature. Due to the different sensitivity of materials to temperature, variation in the processing temperature will lead to varying viscosity of the components in the blends. Based on this principle, the processing temperature could be manipulated to provide a favourable viscosity ratio of below unity for fibre formation. To study the effect of shear rate, the flow rate of the blend and the mould thickness were varied. The shear rate has a significant effect on the fibrillation of the LCP phase. The effect was more prominent when the viscosity ratio was low and the matrix viscosity was high. At 5 wt% LCP, fibrillation did not occur even at low viscosity ratios and high shear rates. It was also observed that the LCP content must be sufficiently high to allow coalescence of the dispersed phase for subsequent fibrillation to occur.
| Original language | English |
|---|---|
| Pages (from-to) | 398-405 |
| Number of pages | 8 |
| Journal | Polymer International |
| Volume | 51 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - May 2002 |
| Externally published | Yes |
ASJC Scopus Subject Areas
- Polymers and Plastics
- Organic Chemistry
- Materials Chemistry
Keywords
- LCP content
- Liquid crystalline polymer
- Shear rate
- Viscosity ratio